fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include "compat.h"
  29 #include "ctree.h"
  30 #include "extent_map.h"
  31 #include "disk-io.h"
  32 #include "transaction.h"
  33 #include "print-tree.h"
  34 #include "volumes.h"
  35 #include "async-thread.h"
  36 #include "check-integrity.h"
  37 #include "rcu-string.h"
  38 #include "math.h"
  39 #include "dev-replace.h"
  40
  41 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  42                                 struct btrfs_root *root,
  43                                 struct btrfs_device *device);
  44 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  45 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  46 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  47
  48 static DEFINE_MUTEX(uuid_mutex);
  49 static LIST_HEAD(fs_uuids);
  50
  51 static void lock_chunks(struct btrfs_root *root)
  52 {
  53         mutex_lock(&root->fs_info->chunk_mutex);
  54 }
  55
  56 static void unlock_chunks(struct btrfs_root *root)
  57 {
  58         mutex_unlock(&root->fs_info->chunk_mutex);
  59 }
  60
  61 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  62 {
  63         struct btrfs_device *device;
  64         WARN_ON(fs_devices->opened);
  65         while (!list_empty(&fs_devices->devices)) {
  66                 device = list_entry(fs_devices->devices.next,
  67                                     struct btrfs_device, dev_list);
  68                 list_del(&device->dev_list);
  69                 rcu_string_free(device->name);
  70                 kfree(device);
  71         }
  72         kfree(fs_devices);
  73 }
  74
  75 static void btrfs_kobject_uevent(struct block_device *bdev,
  76                                  enum kobject_action action)
  77 {
  78         int ret;
  79
  80         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
  81         if (ret)
  82                 pr_warn("Sending event '%d' to kobject: '%s' (%p): failed\n",
  83                         action,
  84                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
  85                         &disk_to_dev(bdev->bd_disk)->kobj);
  86 }
  87
  88 void btrfs_cleanup_fs_uuids(void)
  89 {
  90         struct btrfs_fs_devices *fs_devices;
  91
  92         while (!list_empty(&fs_uuids)) {
  93                 fs_devices = list_entry(fs_uuids.next,
  94                                         struct btrfs_fs_devices, list);
  95                 list_del(&fs_devices->list);
  96                 free_fs_devices(fs_devices);
  97         }
  98 }
  99
 100 static noinline struct btrfs_device *__find_device(struct list_head *head,
 101                                                    u64 devid, u8 *uuid)
 102 {
 103         struct btrfs_device *dev;
 104
 105         list_for_each_entry(dev, head, dev_list) {
 106                 if (dev->devid == devid &&
 107                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 108                         return dev;
 109                 }
 110         }
 111         return NULL;
 112 }
 113
 114 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 115 {
 116         struct btrfs_fs_devices *fs_devices;
 117
 118         list_for_each_entry(fs_devices, &fs_uuids, list) {
 119                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 120                         return fs_devices;
 121         }
 122         return NULL;
 123 }
 124
 125 static int
 126 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 127                       int flush, struct block_device **bdev,
 128                       struct buffer_head **bh)
 129 {
 130         int ret;
 131
 132         *bdev = blkdev_get_by_path(device_path, flags, holder);
 133
 134         if (IS_ERR(*bdev)) {
 135                 ret = PTR_ERR(*bdev);
 136                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
 137                 goto error;
 138         }
 139
 140         if (flush)
 141                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 142         ret = set_blocksize(*bdev, 4096);
 143         if (ret) {
 144                 blkdev_put(*bdev, flags);
 145                 goto error;
 146         }
 147         invalidate_bdev(*bdev);
 148         *bh = btrfs_read_dev_super(*bdev);
 149         if (!*bh) {
 150                 ret = -EINVAL;
 151                 blkdev_put(*bdev, flags);
 152                 goto error;
 153         }
 154
 155         return 0;
 156
 157 error:
 158         *bdev = NULL;
 159         *bh = NULL;
 160         return ret;
 161 }
 162
 163 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 164                         struct bio *head, struct bio *tail)
 165 {
 166
 167         struct bio *old_head;
 168
 169         old_head = pending_bios->head;
 170         pending_bios->head = head;
 171         if (pending_bios->tail)
 172                 tail->bi_next = old_head;
 173         else
 174                 pending_bios->tail = tail;
 175 }
 176
 177 /*
 178  * we try to collect pending bios for a device so we don't get a large
 179  * number of procs sending bios down to the same device.  This greatly
 180  * improves the schedulers ability to collect and merge the bios.
 181  *
 182  * But, it also turns into a long list of bios to process and that is sure
 183  * to eventually make the worker thread block.  The solution here is to
 184  * make some progress and then put this work struct back at the end of
 185  * the list if the block device is congested.  This way, multiple devices
 186  * can make progress from a single worker thread.
 187  */
 188 static noinline void run_scheduled_bios(struct btrfs_device *device)
 189 {
 190         struct bio *pending;
 191         struct backing_dev_info *bdi;
 192         struct btrfs_fs_info *fs_info;
 193         struct btrfs_pending_bios *pending_bios;
 194         struct bio *tail;
 195         struct bio *cur;
 196         int again = 0;
 197         unsigned long num_run;
 198         unsigned long batch_run = 0;
 199         unsigned long limit;
 200         unsigned long last_waited = 0;
 201         int force_reg = 0;
 202         int sync_pending = 0;
 203         struct blk_plug plug;
 204
 205         /*
 206          * this function runs all the bios we've collected for
 207          * a particular device.  We don't want to wander off to
 208          * another device without first sending all of these down.
 209          * So, setup a plug here and finish it off before we return
 210          */
 211         blk_start_plug(&plug);
 212
 213         bdi = blk_get_backing_dev_info(device->bdev);
 214         fs_info = device->dev_root->fs_info;
 215         limit = btrfs_async_submit_limit(fs_info);
 216         limit = limit * 2 / 3;
 217
 218 loop:
 219         spin_lock(&device->io_lock);
 220
 221 loop_lock:
 222         num_run = 0;
 223
 224         /* take all the bios off the list at once and process them
 225          * later on (without the lock held).  But, remember the
 226          * tail and other pointers so the bios can be properly reinserted
 227          * into the list if we hit congestion
 228          */
 229         if (!force_reg && device->pending_sync_bios.head) {
 230                 pending_bios = &device->pending_sync_bios;
 231                 force_reg = 1;
 232         } else {
 233                 pending_bios = &device->pending_bios;
 234                 force_reg = 0;
 235         }
 236
 237         pending = pending_bios->head;
 238         tail = pending_bios->tail;
 239         WARN_ON(pending && !tail);
 240
 241         /*
 242          * if pending was null this time around, no bios need processing
 243          * at all and we can stop.  Otherwise it'll loop back up again
 244          * and do an additional check so no bios are missed.
 245          *
 246          * device->running_pending is used to synchronize with the
 247          * schedule_bio code.
 248          */
 249         if (device->pending_sync_bios.head == NULL &&
 250             device->pending_bios.head == NULL) {
 251                 again = 0;
 252                 device->running_pending = 0;
 253         } else {
 254                 again = 1;
 255                 device->running_pending = 1;
 256         }
 257
 258         pending_bios->head = NULL;
 259         pending_bios->tail = NULL;
 260
 261         spin_unlock(&device->io_lock);
 262
 263         while (pending) {
 264
 265                 rmb();
 266                 /* we want to work on both lists, but do more bios on the
 267                  * sync list than the regular list
 268                  */
 269                 if ((num_run > 32 &&
 270                     pending_bios != &device->pending_sync_bios &&
 271                     device->pending_sync_bios.head) ||
 272                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 273                     device->pending_bios.head)) {
 274                         spin_lock(&device->io_lock);
 275                         requeue_list(pending_bios, pending, tail);
 276                         goto loop_lock;
 277                 }
 278
 279                 cur = pending;
 280                 pending = pending->bi_next;
 281                 cur->bi_next = NULL;
 282
 283                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 284                     waitqueue_active(&fs_info->async_submit_wait))
 285                         wake_up(&fs_info->async_submit_wait);
 286
 287                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 288
 289                 /*
 290                  * if we're doing the sync list, record that our
 291                  * plug has some sync requests on it
 292                  *
 293                  * If we're doing the regular list and there are
 294                  * sync requests sitting around, unplug before
 295                  * we add more
 296                  */
 297                 if (pending_bios == &device->pending_sync_bios) {
 298                         sync_pending = 1;
 299                 } else if (sync_pending) {
 300                         blk_finish_plug(&plug);
 301                         blk_start_plug(&plug);
 302                         sync_pending = 0;
 303                 }
 304
 305                 btrfsic_submit_bio(cur->bi_rw, cur);
 306                 num_run++;
 307                 batch_run++;
 308                 if (need_resched())
 309                         cond_resched();
 310
 311                 /*
 312                  * we made progress, there is more work to do and the bdi
 313                  * is now congested.  Back off and let other work structs
 314                  * run instead
 315                  */
 316                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 317                     fs_info->fs_devices->open_devices > 1) {
 318                         struct io_context *ioc;
 319
 320                         ioc = current->io_context;
 321
 322                         /*
 323                          * the main goal here is that we don't want to
 324                          * block if we're going to be able to submit
 325                          * more requests without blocking.
 326                          *
 327                          * This code does two great things, it pokes into
 328                          * the elevator code from a filesystem _and_
 329                          * it makes assumptions about how batching works.
 330                          */
 331                         if (ioc && ioc->nr_batch_requests > 0 &&
 332                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 333                             (last_waited == 0 ||
 334                              ioc->last_waited == last_waited)) {
 335                                 /*
 336                                  * we want to go through our batch of
 337                                  * requests and stop.  So, we copy out
 338                                  * the ioc->last_waited time and test
 339                                  * against it before looping
 340                                  */
 341                                 last_waited = ioc->last_waited;
 342                                 if (need_resched())
 343                                         cond_resched();
 344                                 continue;
 345                         }
 346                         spin_lock(&device->io_lock);
 347                         requeue_list(pending_bios, pending, tail);
 348                         device->running_pending = 1;
 349
 350                         spin_unlock(&device->io_lock);
 351                         btrfs_requeue_work(&device->work);
 352                         goto done;
 353                 }
 354                 /* unplug every 64 requests just for good measure */
 355                 if (batch_run % 64 == 0) {
 356                         blk_finish_plug(&plug);
 357                         blk_start_plug(&plug);
 358                         sync_pending = 0;
 359                 }
 360         }
 361
 362         cond_resched();
 363         if (again)
 364                 goto loop;
 365
 366         spin_lock(&device->io_lock);
 367         if (device->pending_bios.head || device->pending_sync_bios.head)
 368                 goto loop_lock;
 369         spin_unlock(&device->io_lock);
 370
 371 done:
 372         blk_finish_plug(&plug);
 373 }
 374
 375 static void pending_bios_fn(struct btrfs_work *work)
 376 {
 377         struct btrfs_device *device;
 378
 379         device = container_of(work, struct btrfs_device, work);
 380         run_scheduled_bios(device);
 381 }
 382
 383 static noinline int device_list_add(const char *path,
 384                            struct btrfs_super_block *disk_super,
 385                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 386 {
 387         struct btrfs_device *device;
 388         struct btrfs_fs_devices *fs_devices;
 389         struct rcu_string *name;
 390         u64 found_transid = btrfs_super_generation(disk_super);
 391
 392         fs_devices = find_fsid(disk_super->fsid);
 393         if (!fs_devices) {
 394                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 395                 if (!fs_devices)
 396                         return -ENOMEM;
 397                 INIT_LIST_HEAD(&fs_devices->devices);
 398                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 399                 list_add(&fs_devices->list, &fs_uuids);
 400                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 401                 fs_devices->latest_devid = devid;
 402                 fs_devices->latest_trans = found_transid;
 403                 mutex_init(&fs_devices->device_list_mutex);
 404                 device = NULL;
 405         } else {
 406                 device = __find_device(&fs_devices->devices, devid,
 407                                        disk_super->dev_item.uuid);
 408         }
 409         if (!device) {
 410                 if (fs_devices->opened)
 411                         return -EBUSY;
 412
 413                 device = kzalloc(sizeof(*device), GFP_NOFS);
 414                 if (!device) {
 415                         /* we can safely leave the fs_devices entry around */
 416                         return -ENOMEM;
 417                 }
 418                 device->devid = devid;
 419                 device->dev_stats_valid = 0;
 420                 device->work.func = pending_bios_fn;
 421                 memcpy(device->uuid, disk_super->dev_item.uuid,
 422                        BTRFS_UUID_SIZE);
 423                 spin_lock_init(&device->io_lock);
 424
 425                 name = rcu_string_strdup(path, GFP_NOFS);
 426                 if (!name) {
 427                         kfree(device);
 428                         return -ENOMEM;
 429                 }
 430                 rcu_assign_pointer(device->name, name);
 431                 INIT_LIST_HEAD(&device->dev_alloc_list);
 432
 433                 /* init readahead state */
 434                 spin_lock_init(&device->reada_lock);
 435                 device->reada_curr_zone = NULL;
 436                 atomic_set(&device->reada_in_flight, 0);
 437                 device->reada_next = 0;
 438                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 439                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 440
 441                 mutex_lock(&fs_devices->device_list_mutex);
 442                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 443                 mutex_unlock(&fs_devices->device_list_mutex);
 444
 445                 device->fs_devices = fs_devices;
 446                 fs_devices->num_devices++;
 447         } else if (!device->name || strcmp(device->name->str, path)) {
 448                 name = rcu_string_strdup(path, GFP_NOFS);
 449                 if (!name)
 450                         return -ENOMEM;
 451                 rcu_string_free(device->name);
 452                 rcu_assign_pointer(device->name, name);
 453                 if (device->missing) {
 454                         fs_devices->missing_devices--;
 455                         device->missing = 0;
 456                 }
 457         }
 458
 459         if (found_transid > fs_devices->latest_trans) {
 460                 fs_devices->latest_devid = devid;
 461                 fs_devices->latest_trans = found_transid;
 462         }
 463         *fs_devices_ret = fs_devices;
 464         return 0;
 465 }
 466
 467 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 468 {
 469         struct btrfs_fs_devices *fs_devices;
 470         struct btrfs_device *device;
 471         struct btrfs_device *orig_dev;
 472
 473         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 474         if (!fs_devices)
 475                 return ERR_PTR(-ENOMEM);
 476
 477         INIT_LIST_HEAD(&fs_devices->devices);
 478         INIT_LIST_HEAD(&fs_devices->alloc_list);
 479         INIT_LIST_HEAD(&fs_devices->list);
 480         mutex_init(&fs_devices->device_list_mutex);
 481         fs_devices->latest_devid = orig->latest_devid;
 482         fs_devices->latest_trans = orig->latest_trans;
 483         fs_devices->total_devices = orig->total_devices;
 484         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 485
 486         /* We have held the volume lock, it is safe to get the devices. */
 487         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 488                 struct rcu_string *name;
 489
 490                 device = kzalloc(sizeof(*device), GFP_NOFS);
 491                 if (!device)
 492                         goto error;
 493
 494                 /*
 495                  * This is ok to do without rcu read locked because we hold the
 496                  * uuid mutex so nothing we touch in here is going to disappear.
 497                  */
 498                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 499                 if (!name) {
 500                         kfree(device);
 501                         goto error;
 502                 }
 503                 rcu_assign_pointer(device->name, name);
 504
 505                 device->devid = orig_dev->devid;
 506                 device->work.func = pending_bios_fn;
 507                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 508                 spin_lock_init(&device->io_lock);
 509                 INIT_LIST_HEAD(&device->dev_list);
 510                 INIT_LIST_HEAD(&device->dev_alloc_list);
 511
 512                 list_add(&device->dev_list, &fs_devices->devices);
 513                 device->fs_devices = fs_devices;
 514                 fs_devices->num_devices++;
 515         }
 516         return fs_devices;
 517 error:
 518         free_fs_devices(fs_devices);
 519         return ERR_PTR(-ENOMEM);
 520 }
 521
 522 void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
 523                                struct btrfs_fs_devices *fs_devices, int step)
 524 {
 525         struct btrfs_device *device, *next;
 526
 527         struct block_device *latest_bdev = NULL;
 528         u64 latest_devid = 0;
 529         u64 latest_transid = 0;
 530
 531         mutex_lock(&uuid_mutex);
 532 again:
 533         /* This is the initialized path, it is safe to release the devices. */
 534         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 535                 if (device->in_fs_metadata) {
 536                         if (!device->is_tgtdev_for_dev_replace &&
 537                             (!latest_transid ||
 538                              device->generation > latest_transid)) {
 539                                 latest_devid = device->devid;
 540                                 latest_transid = device->generation;
 541                                 latest_bdev = device->bdev;
 542                         }
 543                         continue;
 544                 }
 545
 546                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 547                         /*
 548                          * In the first step, keep the device which has
 549                          * the correct fsid and the devid that is used
 550                          * for the dev_replace procedure.
 551                          * In the second step, the dev_replace state is
 552                          * read from the device tree and it is known
 553                          * whether the procedure is really active or
 554                          * not, which means whether this device is
 555                          * used or whether it should be removed.
 556                          */
 557                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 558                                 continue;
 559                         }
 560                 }
 561                 if (device->bdev) {
 562                         blkdev_put(device->bdev, device->mode);
 563                         device->bdev = NULL;
 564                         fs_devices->open_devices--;
 565                 }
 566                 if (device->writeable) {
 567                         list_del_init(&device->dev_alloc_list);
 568                         device->writeable = 0;
 569                         if (!device->is_tgtdev_for_dev_replace)
 570                                 fs_devices->rw_devices--;
 571                 }
 572                 list_del_init(&device->dev_list);
 573                 fs_devices->num_devices--;
 574                 rcu_string_free(device->name);
 575                 kfree(device);
 576         }
 577
 578         if (fs_devices->seed) {
 579                 fs_devices = fs_devices->seed;
 580                 goto again;
 581         }
 582
 583         fs_devices->latest_bdev = latest_bdev;
 584         fs_devices->latest_devid = latest_devid;
 585         fs_devices->latest_trans = latest_transid;
 586
 587         mutex_unlock(&uuid_mutex);
 588 }
 589
 590 static void __free_device(struct work_struct *work)
 591 {
 592         struct btrfs_device *device;
 593
 594         device = container_of(work, struct btrfs_device, rcu_work);
 595
 596         if (device->bdev)
 597                 blkdev_put(device->bdev, device->mode);
 598
 599         rcu_string_free(device->name);
 600         kfree(device);
 601 }
 602
 603 static void free_device(struct rcu_head *head)
 604 {
 605         struct btrfs_device *device;
 606
 607         device = container_of(head, struct btrfs_device, rcu);
 608
 609         INIT_WORK(&device->rcu_work, __free_device);
 610         schedule_work(&device->rcu_work);
 611 }
 612
 613 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 614 {
 615         struct btrfs_device *device;
 616
 617         if (--fs_devices->opened > 0)
 618                 return 0;
 619
 620         mutex_lock(&fs_devices->device_list_mutex);
 621         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 622                 struct btrfs_device *new_device;
 623                 struct rcu_string *name;
 624
 625                 if (device->bdev)
 626                         fs_devices->open_devices--;
 627
 628                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 629                         list_del_init(&device->dev_alloc_list);
 630                         fs_devices->rw_devices--;
 631                 }
 632
 633                 if (device->can_discard)
 634                         fs_devices->num_can_discard--;
 635
 636                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 637                 BUG_ON(!new_device); /* -ENOMEM */
 638                 memcpy(new_device, device, sizeof(*new_device));
 639
 640                 /* Safe because we are under uuid_mutex */
 641                 if (device->name) {
 642                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
 643                         BUG_ON(device->name && !name); /* -ENOMEM */
 644                         rcu_assign_pointer(new_device->name, name);
 645                 }
 646                 new_device->bdev = NULL;
 647                 new_device->writeable = 0;
 648                 new_device->in_fs_metadata = 0;
 649                 new_device->can_discard = 0;
 650                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 651
 652                 call_rcu(&device->rcu, free_device);
 653         }
 654         mutex_unlock(&fs_devices->device_list_mutex);
 655
 656         WARN_ON(fs_devices->open_devices);
 657         WARN_ON(fs_devices->rw_devices);
 658         fs_devices->opened = 0;
 659         fs_devices->seeding = 0;
 660
 661         return 0;
 662 }
 663
 664 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 665 {
 666         struct btrfs_fs_devices *seed_devices = NULL;
 667         int ret;
 668
 669         mutex_lock(&uuid_mutex);
 670         ret = __btrfs_close_devices(fs_devices);
 671         if (!fs_devices->opened) {
 672                 seed_devices = fs_devices->seed;
 673                 fs_devices->seed = NULL;
 674         }
 675         mutex_unlock(&uuid_mutex);
 676
 677         while (seed_devices) {
 678                 fs_devices = seed_devices;
 679                 seed_devices = fs_devices->seed;
 680                 __btrfs_close_devices(fs_devices);
 681                 free_fs_devices(fs_devices);
 682         }
 683         return ret;
 684 }
 685
 686 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 687                                 fmode_t flags, void *holder)
 688 {
 689         struct request_queue *q;
 690         struct block_device *bdev;
 691         struct list_head *head = &fs_devices->devices;
 692         struct btrfs_device *device;
 693         struct block_device *latest_bdev = NULL;
 694         struct buffer_head *bh;
 695         struct btrfs_super_block *disk_super;
 696         u64 latest_devid = 0;
 697         u64 latest_transid = 0;
 698         u64 devid;
 699         int seeding = 1;
 700         int ret = 0;
 701
 702         flags |= FMODE_EXCL;
 703
 704         list_for_each_entry(device, head, dev_list) {
 705                 if (device->bdev)
 706                         continue;
 707                 if (!device->name)
 708                         continue;
 709
 710                 ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 711                                             &bdev, &bh);
 712                 if (ret)
 713                         continue;
 714
 715                 disk_super = (struct btrfs_super_block *)bh->b_data;
 716                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 717                 if (devid != device->devid)
 718                         goto error_brelse;
 719
 720                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 721                            BTRFS_UUID_SIZE))
 722                         goto error_brelse;
 723
 724                 device->generation = btrfs_super_generation(disk_super);
 725                 if (!latest_transid || device->generation > latest_transid) {
 726                         latest_devid = devid;
 727                         latest_transid = device->generation;
 728                         latest_bdev = bdev;
 729                 }
 730
 731                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 732                         device->writeable = 0;
 733                 } else {
 734                         device->writeable = !bdev_read_only(bdev);
 735                         seeding = 0;
 736                 }
 737
 738                 q = bdev_get_queue(bdev);
 739                 if (blk_queue_discard(q)) {
 740                         device->can_discard = 1;
 741                         fs_devices->num_can_discard++;
 742                 }
 743
 744                 device->bdev = bdev;
 745                 device->in_fs_metadata = 0;
 746                 device->mode = flags;
 747
 748                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 749                         fs_devices->rotating = 1;
 750
 751                 fs_devices->open_devices++;
 752                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 753                         fs_devices->rw_devices++;
 754                         list_add(&device->dev_alloc_list,
 755                                  &fs_devices->alloc_list);
 756                 }
 757                 brelse(bh);
 758                 continue;
 759
 760 error_brelse:
 761                 brelse(bh);
 762                 blkdev_put(bdev, flags);
 763                 continue;
 764         }
 765         if (fs_devices->open_devices == 0) {
 766                 ret = -EINVAL;
 767                 goto out;
 768         }
 769         fs_devices->seeding = seeding;
 770         fs_devices->opened = 1;
 771         fs_devices->latest_bdev = latest_bdev;
 772         fs_devices->latest_devid = latest_devid;
 773         fs_devices->latest_trans = latest_transid;
 774         fs_devices->total_rw_bytes = 0;
 775 out:
 776         return ret;
 777 }
 778
 779 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 780                        fmode_t flags, void *holder)
 781 {
 782         int ret;
 783
 784         mutex_lock(&uuid_mutex);
 785         if (fs_devices->opened) {
 786                 fs_devices->opened++;
 787                 ret = 0;
 788         } else {
 789                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 790         }
 791         mutex_unlock(&uuid_mutex);
 792         return ret;
 793 }
 794
 795 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 796                           struct btrfs_fs_devices **fs_devices_ret)
 797 {
 798         struct btrfs_super_block *disk_super;
 799         struct block_device *bdev;
 800         struct buffer_head *bh;
 801         int ret;
 802         u64 devid;
 803         u64 transid;
 804         u64 total_devices;
 805
 806         flags |= FMODE_EXCL;
 807         mutex_lock(&uuid_mutex);
 808         ret = btrfs_get_bdev_and_sb(path, flags, holder, 0, &bdev, &bh);
 809         if (ret)
 810                 goto error;
 811         disk_super = (struct btrfs_super_block *)bh->b_data;
 812         devid = btrfs_stack_device_id(&disk_super->dev_item);
 813         transid = btrfs_super_generation(disk_super);
 814         total_devices = btrfs_super_num_devices(disk_super);
 815         if (disk_super->label[0]) {
 816                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
 817                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
 818                 printk(KERN_INFO "device label %s ", disk_super->label);
 819         } else {
 820                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 821         }
 822         printk(KERN_CONT "devid %llu transid %llu %s\n",
 823                (unsigned long long)devid, (unsigned long long)transid, path);
 824         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 825         if (!ret && fs_devices_ret)
 826                 (*fs_devices_ret)->total_devices = total_devices;
 827         brelse(bh);
 828         blkdev_put(bdev, flags);
 829 error:
 830         mutex_unlock(&uuid_mutex);
 831         return ret;
 832 }
 833
 834 /* helper to account the used device space in the range */
 835 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 836                                    u64 end, u64 *length)
 837 {
 838         struct btrfs_key key;
 839         struct btrfs_root *root = device->dev_root;
 840         struct btrfs_dev_extent *dev_extent;
 841         struct btrfs_path *path;
 842         u64 extent_end;
 843         int ret;
 844         int slot;
 845         struct extent_buffer *l;
 846
 847         *length = 0;
 848
 849         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
 850                 return 0;
 851
 852         path = btrfs_alloc_path();
 853         if (!path)
 854                 return -ENOMEM;
 855         path->reada = 2;
 856
 857         key.objectid = device->devid;
 858         key.offset = start;
 859         key.type = BTRFS_DEV_EXTENT_KEY;
 860
 861         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 862         if (ret < 0)
 863                 goto out;
 864         if (ret > 0) {
 865                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 866                 if (ret < 0)
 867                         goto out;
 868         }
 869
 870         while (1) {
 871                 l = path->nodes[0];
 872                 slot = path->slots[0];
 873                 if (slot >= btrfs_header_nritems(l)) {
 874                         ret = btrfs_next_leaf(root, path);
 875                         if (ret == 0)
 876                                 continue;
 877                         if (ret < 0)
 878                                 goto out;
 879
 880                         break;
 881                 }
 882                 btrfs_item_key_to_cpu(l, &key, slot);
 883
 884                 if (key.objectid < device->devid)
 885                         goto next;
 886
 887                 if (key.objectid > device->devid)
 888                         break;
 889
 890                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 891                         goto next;
 892
 893                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 894                 extent_end = key.offset + btrfs_dev_extent_length(l,
 895                                                                   dev_extent);
 896                 if (key.offset <= start && extent_end > end) {
 897                         *length = end - start + 1;
 898                         break;
 899                 } else if (key.offset <= start && extent_end > start)
 900                         *length += extent_end - start;
 901                 else if (key.offset > start && extent_end <= end)
 902                         *length += extent_end - key.offset;
 903                 else if (key.offset > start && key.offset <= end) {
 904                         *length += end - key.offset + 1;
 905                         break;
 906                 } else if (key.offset > end)
 907                         break;
 908
 909 next:
 910                 path->slots[0]++;
 911         }
 912         ret = 0;
 913 out:
 914         btrfs_free_path(path);
 915         return ret;
 916 }
 917
 918 /*
 919  * find_free_dev_extent - find free space in the specified device
 920  * @device:     the device which we search the free space in
 921  * @num_bytes:  the size of the free space that we need
 922  * @start:      store the start of the free space.
 923  * @len:        the size of the free space. that we find, or the size of the max
 924  *              free space if we don't find suitable free space
 925  *
 926  * this uses a pretty simple search, the expectation is that it is
 927  * called very infrequently and that a given device has a small number
 928  * of extents
 929  *
 930  * @start is used to store the start of the free space if we find. But if we
 931  * don't find suitable free space, it will be used to store the start position
 932  * of the max free space.
 933  *
 934  * @len is used to store the size of the free space that we find.
 935  * But if we don't find suitable free space, it is used to store the size of
 936  * the max free space.
 937  */
 938 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 939                          u64 *start, u64 *len)
 940 {
 941         struct btrfs_key key;
 942         struct btrfs_root *root = device->dev_root;
 943         struct btrfs_dev_extent *dev_extent;
 944         struct btrfs_path *path;
 945         u64 hole_size;
 946         u64 max_hole_start;
 947         u64 max_hole_size;
 948         u64 extent_end;
 949         u64 search_start;
 950         u64 search_end = device->total_bytes;
 951         int ret;
 952         int slot;
 953         struct extent_buffer *l;
 954
 955         /* FIXME use last free of some kind */
 956
 957         /* we don't want to overwrite the superblock on the drive,
 958          * so we make sure to start at an offset of at least 1MB
 959          */
 960         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 961
 962         max_hole_start = search_start;
 963         max_hole_size = 0;
 964         hole_size = 0;
 965
 966         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
 967                 ret = -ENOSPC;
 968                 goto error;
 969         }
 970
 971         path = btrfs_alloc_path();
 972         if (!path) {
 973                 ret = -ENOMEM;
 974                 goto error;
 975         }
 976         path->reada = 2;
 977
 978         key.objectid = device->devid;
 979         key.offset = search_start;
 980         key.type = BTRFS_DEV_EXTENT_KEY;
 981
 982         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 983         if (ret < 0)
 984                 goto out;
 985         if (ret > 0) {
 986                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 987                 if (ret < 0)
 988                         goto out;
 989         }
 990
 991         while (1) {
 992                 l = path->nodes[0];
 993                 slot = path->slots[0];
 994                 if (slot >= btrfs_header_nritems(l)) {
 995                         ret = btrfs_next_leaf(root, path);
 996                         if (ret == 0)
 997                                 continue;
 998                         if (ret < 0)
 999                                 goto out;
1000
1001                         break;
1002                 }
1003                 btrfs_item_key_to_cpu(l, &key, slot);
1004
1005                 if (key.objectid < device->devid)
1006                         goto next;
1007
1008                 if (key.objectid > device->devid)
1009                         break;
1010
1011                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1012                         goto next;
1013
1014                 if (key.offset > search_start) {
1015                         hole_size = key.offset - search_start;
1016
1017                         if (hole_size > max_hole_size) {
1018                                 max_hole_start = search_start;
1019                                 max_hole_size = hole_size;
1020                         }
1021
1022                         /*
1023                          * If this free space is greater than which we need,
1024                          * it must be the max free space that we have found
1025                          * until now, so max_hole_start must point to the start
1026                          * of this free space and the length of this free space
1027                          * is stored in max_hole_size. Thus, we return
1028                          * max_hole_start and max_hole_size and go back to the
1029                          * caller.
1030                          */
1031                         if (hole_size >= num_bytes) {
1032                                 ret = 0;
1033                                 goto out;
1034                         }
1035                 }
1036
1037                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1038                 extent_end = key.offset + btrfs_dev_extent_length(l,
1039                                                                   dev_extent);
1040                 if (extent_end > search_start)
1041                         search_start = extent_end;
1042 next:
1043                 path->slots[0]++;
1044                 cond_resched();
1045         }
1046
1047         /*
1048          * At this point, search_start should be the end of
1049          * allocated dev extents, and when shrinking the device,
1050          * search_end may be smaller than search_start.
1051          */
1052         if (search_end > search_start)
1053                 hole_size = search_end - search_start;
1054
1055         if (hole_size > max_hole_size) {
1056                 max_hole_start = search_start;
1057                 max_hole_size = hole_size;
1058         }
1059
1060         /* See above. */
1061         if (hole_size < num_bytes)
1062                 ret = -ENOSPC;
1063         else
1064                 ret = 0;
1065
1066 out:
1067         btrfs_free_path(path);
1068 error:
1069         *start = max_hole_start;
1070         if (len)
1071                 *len = max_hole_size;
1072         return ret;
1073 }
1074
1075 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1076                           struct btrfs_device *device,
1077                           u64 start)
1078 {
1079         int ret;
1080         struct btrfs_path *path;
1081         struct btrfs_root *root = device->dev_root;
1082         struct btrfs_key key;
1083         struct btrfs_key found_key;
1084         struct extent_buffer *leaf = NULL;
1085         struct btrfs_dev_extent *extent = NULL;
1086
1087         path = btrfs_alloc_path();
1088         if (!path)
1089                 return -ENOMEM;
1090
1091         key.objectid = device->devid;
1092         key.offset = start;
1093         key.type = BTRFS_DEV_EXTENT_KEY;
1094 again:
1095         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1096         if (ret > 0) {
1097                 ret = btrfs_previous_item(root, path, key.objectid,
1098                                           BTRFS_DEV_EXTENT_KEY);
1099                 if (ret)
1100                         goto out;
1101                 leaf = path->nodes[0];
1102                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1103                 extent = btrfs_item_ptr(leaf, path->slots[0],
1104                                         struct btrfs_dev_extent);
1105                 BUG_ON(found_key.offset > start || found_key.offset +
1106                        btrfs_dev_extent_length(leaf, extent) < start);
1107                 key = found_key;
1108                 btrfs_release_path(path);
1109                 goto again;
1110         } else if (ret == 0) {
1111                 leaf = path->nodes[0];
1112                 extent = btrfs_item_ptr(leaf, path->slots[0],
1113                                         struct btrfs_dev_extent);
1114         } else {
1115                 btrfs_error(root->fs_info, ret, "Slot search failed");
1116                 goto out;
1117         }
1118
1119         if (device->bytes_used > 0) {
1120                 u64 len = btrfs_dev_extent_length(leaf, extent);
1121                 device->bytes_used -= len;
1122                 spin_lock(&root->fs_info->free_chunk_lock);
1123                 root->fs_info->free_chunk_space += len;
1124                 spin_unlock(&root->fs_info->free_chunk_lock);
1125         }
1126         ret = btrfs_del_item(trans, root, path);
1127         if (ret) {
1128                 btrfs_error(root->fs_info, ret,
1129                             "Failed to remove dev extent item");
1130         }
1131 out:
1132         btrfs_free_path(path);
1133         return ret;
1134 }
1135
1136 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1137                            struct btrfs_device *device,
1138                            u64 chunk_tree, u64 chunk_objectid,
1139                            u64 chunk_offset, u64 start, u64 num_bytes)
1140 {
1141         int ret;
1142         struct btrfs_path *path;
1143         struct btrfs_root *root = device->dev_root;
1144         struct btrfs_dev_extent *extent;
1145         struct extent_buffer *leaf;
1146         struct btrfs_key key;
1147
1148         WARN_ON(!device->in_fs_metadata);
1149         WARN_ON(device->is_tgtdev_for_dev_replace);
1150         path = btrfs_alloc_path();
1151         if (!path)
1152                 return -ENOMEM;
1153
1154         key.objectid = device->devid;
1155         key.offset = start;
1156         key.type = BTRFS_DEV_EXTENT_KEY;
1157         ret = btrfs_insert_empty_item(trans, root, path, &key,
1158                                       sizeof(*extent));
1159         if (ret)
1160                 goto out;
1161
1162         leaf = path->nodes[0];
1163         extent = btrfs_item_ptr(leaf, path->slots[0],
1164                                 struct btrfs_dev_extent);
1165         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1166         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1167         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1168
1169         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1170                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1171                     BTRFS_UUID_SIZE);
1172
1173         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1174         btrfs_mark_buffer_dirty(leaf);
1175 out:
1176         btrfs_free_path(path);
1177         return ret;
1178 }
1179
1180 static noinline int find_next_chunk(struct btrfs_root *root,
1181                                     u64 objectid, u64 *offset)
1182 {
1183         struct btrfs_path *path;
1184         int ret;
1185         struct btrfs_key key;
1186         struct btrfs_chunk *chunk;
1187         struct btrfs_key found_key;
1188
1189         path = btrfs_alloc_path();
1190         if (!path)
1191                 return -ENOMEM;
1192
1193         key.objectid = objectid;
1194         key.offset = (u64)-1;
1195         key.type = BTRFS_CHUNK_ITEM_KEY;
1196
1197         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1198         if (ret < 0)
1199                 goto error;
1200
1201         BUG_ON(ret == 0); /* Corruption */
1202
1203         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1204         if (ret) {
1205                 *offset = 0;
1206         } else {
1207                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1208                                       path->slots[0]);
1209                 if (found_key.objectid != objectid)
1210                         *offset = 0;
1211                 else {
1212                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1213                                                struct btrfs_chunk);
1214                         *offset = found_key.offset +
1215                                 btrfs_chunk_length(path->nodes[0], chunk);
1216                 }
1217         }
1218         ret = 0;
1219 error:
1220         btrfs_free_path(path);
1221         return ret;
1222 }
1223
1224 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1225 {
1226         int ret;
1227         struct btrfs_key key;
1228         struct btrfs_key found_key;
1229         struct btrfs_path *path;
1230
1231         root = root->fs_info->chunk_root;
1232
1233         path = btrfs_alloc_path();
1234         if (!path)
1235                 return -ENOMEM;
1236
1237         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1238         key.type = BTRFS_DEV_ITEM_KEY;
1239         key.offset = (u64)-1;
1240
1241         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1242         if (ret < 0)
1243                 goto error;
1244
1245         BUG_ON(ret == 0); /* Corruption */
1246
1247         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1248                                   BTRFS_DEV_ITEM_KEY);
1249         if (ret) {
1250                 *objectid = 1;
1251         } else {
1252                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1253                                       path->slots[0]);
1254                 *objectid = found_key.offset + 1;
1255         }
1256         ret = 0;
1257 error:
1258         btrfs_free_path(path);
1259         return ret;
1260 }
1261
1262 /*
1263  * the device information is stored in the chunk root
1264  * the btrfs_device struct should be fully filled in
1265  */
1266 int btrfs_add_device(struct btrfs_trans_handle *trans,
1267                      struct btrfs_root *root,
1268                      struct btrfs_device *device)
1269 {
1270         int ret;
1271         struct btrfs_path *path;
1272         struct btrfs_dev_item *dev_item;
1273         struct extent_buffer *leaf;
1274         struct btrfs_key key;
1275         unsigned long ptr;
1276
1277         root = root->fs_info->chunk_root;
1278
1279         path = btrfs_alloc_path();
1280         if (!path)
1281                 return -ENOMEM;
1282
1283         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1284         key.type = BTRFS_DEV_ITEM_KEY;
1285         key.offset = device->devid;
1286
1287         ret = btrfs_insert_empty_item(trans, root, path, &key,
1288                                       sizeof(*dev_item));
1289         if (ret)
1290                 goto out;
1291
1292         leaf = path->nodes[0];
1293         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1294
1295         btrfs_set_device_id(leaf, dev_item, device->devid);
1296         btrfs_set_device_generation(leaf, dev_item, 0);
1297         btrfs_set_device_type(leaf, dev_item, device->type);
1298         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1299         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1300         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1301         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1302         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1303         btrfs_set_device_group(leaf, dev_item, 0);
1304         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1305         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1306         btrfs_set_device_start_offset(leaf, dev_item, 0);
1307
1308         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1309         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1310         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1311         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1312         btrfs_mark_buffer_dirty(leaf);
1313
1314         ret = 0;
1315 out:
1316         btrfs_free_path(path);
1317         return ret;
1318 }
1319
1320 static int btrfs_rm_dev_item(struct btrfs_root *root,
1321                              struct btrfs_device *device)
1322 {
1323         int ret;
1324         struct btrfs_path *path;
1325         struct btrfs_key key;
1326         struct btrfs_trans_handle *trans;
1327
1328         root = root->fs_info->chunk_root;
1329
1330         path = btrfs_alloc_path();
1331         if (!path)
1332                 return -ENOMEM;
1333
1334         trans = btrfs_start_transaction(root, 0);
1335         if (IS_ERR(trans)) {
1336                 btrfs_free_path(path);
1337                 return PTR_ERR(trans);
1338         }
1339         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1340         key.type = BTRFS_DEV_ITEM_KEY;
1341         key.offset = device->devid;
1342         lock_chunks(root);
1343
1344         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1345         if (ret < 0)
1346                 goto out;
1347
1348         if (ret > 0) {
1349                 ret = -ENOENT;
1350                 goto out;
1351         }
1352
1353         ret = btrfs_del_item(trans, root, path);
1354         if (ret)
1355                 goto out;
1356 out:
1357         btrfs_free_path(path);
1358         unlock_chunks(root);
1359         btrfs_commit_transaction(trans, root);
1360         return ret;
1361 }
1362
1363 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1364 {
1365         struct btrfs_device *device;
1366         struct btrfs_device *next_device;
1367         struct block_device *bdev;
1368         struct buffer_head *bh = NULL;
1369         struct btrfs_super_block *disk_super;
1370         struct btrfs_fs_devices *cur_devices;
1371         u64 all_avail;
1372         u64 devid;
1373         u64 num_devices;
1374         u8 *dev_uuid;
1375         int ret = 0;
1376         bool clear_super = false;
1377
1378         mutex_lock(&uuid_mutex);
1379
1380         all_avail = root->fs_info->avail_data_alloc_bits |
1381                 root->fs_info->avail_system_alloc_bits |
1382                 root->fs_info->avail_metadata_alloc_bits;
1383
1384         num_devices = root->fs_info->fs_devices->num_devices;
1385         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1386         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1387                 WARN_ON(num_devices < 1);
1388                 num_devices--;
1389         }
1390         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1391
1392         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1393                 printk(KERN_ERR "btrfs: unable to go below four devices "
1394                        "on raid10\n");
1395                 ret = -EINVAL;
1396                 goto out;
1397         }
1398
1399         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1400                 printk(KERN_ERR "btrfs: unable to go below two "
1401                        "devices on raid1\n");
1402                 ret = -EINVAL;
1403                 goto out;
1404         }
1405
1406         if (strcmp(device_path, "missing") == 0) {
1407                 struct list_head *devices;
1408                 struct btrfs_device *tmp;
1409
1410                 device = NULL;
1411                 devices = &root->fs_info->fs_devices->devices;
1412                 /*
1413                  * It is safe to read the devices since the volume_mutex
1414                  * is held.
1415                  */
1416                 list_for_each_entry(tmp, devices, dev_list) {
1417                         if (tmp->in_fs_metadata &&
1418                             !tmp->is_tgtdev_for_dev_replace &&
1419                             !tmp->bdev) {
1420                                 device = tmp;
1421                                 break;
1422                         }
1423                 }
1424                 bdev = NULL;
1425                 bh = NULL;
1426                 disk_super = NULL;
1427                 if (!device) {
1428                         printk(KERN_ERR "btrfs: no missing devices found to "
1429                                "remove\n");
1430                         goto out;
1431                 }
1432         } else {
1433                 ret = btrfs_get_bdev_and_sb(device_path,
1434                                             FMODE_READ | FMODE_EXCL,
1435                                             root->fs_info->bdev_holder, 0,
1436                                             &bdev, &bh);
1437                 if (ret)
1438                         goto out;
1439                 disk_super = (struct btrfs_super_block *)bh->b_data;
1440                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1441                 dev_uuid = disk_super->dev_item.uuid;
1442                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1443                                            disk_super->fsid);
1444                 if (!device) {
1445                         ret = -ENOENT;
1446                         goto error_brelse;
1447                 }
1448         }
1449
1450         if (device->is_tgtdev_for_dev_replace) {
1451                 pr_err("btrfs: unable to remove the dev_replace target dev\n");
1452                 ret = -EINVAL;
1453                 goto error_brelse;
1454         }
1455
1456         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1457                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1458                        "device\n");
1459                 ret = -EINVAL;
1460                 goto error_brelse;
1461         }
1462
1463         if (device->writeable) {
1464                 lock_chunks(root);
1465                 list_del_init(&device->dev_alloc_list);
1466                 unlock_chunks(root);
1467                 root->fs_info->fs_devices->rw_devices--;
1468                 clear_super = true;
1469         }
1470
1471         ret = btrfs_shrink_device(device, 0);
1472         if (ret)
1473                 goto error_undo;
1474
1475         /*
1476          * TODO: the superblock still includes this device in its num_devices
1477          * counter although write_all_supers() is not locked out. This
1478          * could give a filesystem state which requires a degraded mount.
1479          */
1480         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1481         if (ret)
1482                 goto error_undo;
1483
1484         spin_lock(&root->fs_info->free_chunk_lock);
1485         root->fs_info->free_chunk_space = device->total_bytes -
1486                 device->bytes_used;
1487         spin_unlock(&root->fs_info->free_chunk_lock);
1488
1489         device->in_fs_metadata = 0;
1490         btrfs_scrub_cancel_dev(root->fs_info, device);
1491
1492         /*
1493          * the device list mutex makes sure that we don't change
1494          * the device list while someone else is writing out all
1495          * the device supers.
1496          */
1497
1498         cur_devices = device->fs_devices;
1499         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1500         list_del_rcu(&device->dev_list);
1501
1502         device->fs_devices->num_devices--;
1503         device->fs_devices->total_devices--;
1504
1505         if (device->missing)
1506                 root->fs_info->fs_devices->missing_devices--;
1507
1508         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1509                                  struct btrfs_device, dev_list);
1510         if (device->bdev == root->fs_info->sb->s_bdev)
1511                 root->fs_info->sb->s_bdev = next_device->bdev;
1512         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1513                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1514
1515         if (device->bdev)
1516                 device->fs_devices->open_devices--;
1517
1518         call_rcu(&device->rcu, free_device);
1519         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1520
1521         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1522         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1523
1524         if (cur_devices->open_devices == 0) {
1525                 struct btrfs_fs_devices *fs_devices;
1526                 fs_devices = root->fs_info->fs_devices;
1527                 while (fs_devices) {
1528                         if (fs_devices->seed == cur_devices)
1529                                 break;
1530                         fs_devices = fs_devices->seed;
1531                 }
1532                 fs_devices->seed = cur_devices->seed;
1533                 cur_devices->seed = NULL;
1534                 lock_chunks(root);
1535                 __btrfs_close_devices(cur_devices);
1536                 unlock_chunks(root);
1537                 free_fs_devices(cur_devices);
1538         }
1539
1540         root->fs_info->num_tolerated_disk_barrier_failures =
1541                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1542
1543         /*
1544          * at this point, the device is zero sized.  We want to
1545          * remove it from the devices list and zero out the old super
1546          */
1547         if (clear_super && disk_super) {
1548                 /* make sure this device isn't detected as part of
1549                  * the FS anymore
1550                  */
1551                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1552                 set_buffer_dirty(bh);
1553                 sync_dirty_buffer(bh);
1554         }
1555
1556         ret = 0;
1557
1558         /* Notify udev that device has changed */
1559         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1560
1561 error_brelse:
1562         brelse(bh);
1563         if (bdev)
1564                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1565 out:
1566         mutex_unlock(&uuid_mutex);
1567         return ret;
1568 error_undo:
1569         if (device->writeable) {
1570                 lock_chunks(root);
1571                 list_add(&device->dev_alloc_list,
1572                          &root->fs_info->fs_devices->alloc_list);
1573                 unlock_chunks(root);
1574                 root->fs_info->fs_devices->rw_devices++;
1575         }
1576         goto error_brelse;
1577 }
1578
1579 void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
1580                                  struct btrfs_device *srcdev)
1581 {
1582         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1583         list_del_rcu(&srcdev->dev_list);
1584         list_del_rcu(&srcdev->dev_alloc_list);
1585         fs_info->fs_devices->num_devices--;
1586         if (srcdev->missing) {
1587                 fs_info->fs_devices->missing_devices--;
1588                 fs_info->fs_devices->rw_devices++;
1589         }
1590         if (srcdev->can_discard)
1591                 fs_info->fs_devices->num_can_discard--;
1592         if (srcdev->bdev)
1593                 fs_info->fs_devices->open_devices--;
1594
1595         call_rcu(&srcdev->rcu, free_device);
1596 }
1597
1598 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
1599                                       struct btrfs_device *tgtdev)
1600 {
1601         struct btrfs_device *next_device;
1602
1603         WARN_ON(!tgtdev);
1604         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1605         if (tgtdev->bdev) {
1606                 btrfs_scratch_superblock(tgtdev);
1607                 fs_info->fs_devices->open_devices--;
1608         }
1609         fs_info->fs_devices->num_devices--;
1610         if (tgtdev->can_discard)
1611                 fs_info->fs_devices->num_can_discard++;
1612
1613         next_device = list_entry(fs_info->fs_devices->devices.next,
1614                                  struct btrfs_device, dev_list);
1615         if (tgtdev->bdev == fs_info->sb->s_bdev)
1616                 fs_info->sb->s_bdev = next_device->bdev;
1617         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
1618                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1619         list_del_rcu(&tgtdev->dev_list);
1620
1621         call_rcu(&tgtdev->rcu, free_device);
1622
1623         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1624 }
1625
1626 int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1627                               struct btrfs_device **device)
1628 {
1629         int ret = 0;
1630         struct btrfs_super_block *disk_super;
1631         u64 devid;
1632         u8 *dev_uuid;
1633         struct block_device *bdev;
1634         struct buffer_head *bh;
1635
1636         *device = NULL;
1637         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1638                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1639         if (ret)
1640                 return ret;
1641         disk_super = (struct btrfs_super_block *)bh->b_data;
1642         devid = btrfs_stack_device_id(&disk_super->dev_item);
1643         dev_uuid = disk_super->dev_item.uuid;
1644         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1645                                     disk_super->fsid);
1646         brelse(bh);
1647         if (!*device)
1648                 ret = -ENOENT;
1649         blkdev_put(bdev, FMODE_READ);
1650         return ret;
1651 }
1652
1653 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1654                                          char *device_path,
1655                                          struct btrfs_device **device)
1656 {
1657         *device = NULL;
1658         if (strcmp(device_path, "missing") == 0) {
1659                 struct list_head *devices;
1660                 struct btrfs_device *tmp;
1661
1662                 devices = &root->fs_info->fs_devices->devices;
1663                 /*
1664                  * It is safe to read the devices since the volume_mutex
1665                  * is held by the caller.
1666                  */
1667                 list_for_each_entry(tmp, devices, dev_list) {
1668                         if (tmp->in_fs_metadata && !tmp->bdev) {
1669                                 *device = tmp;
1670                                 break;
1671                         }
1672                 }
1673
1674                 if (!*device) {
1675                         pr_err("btrfs: no missing device found\n");
1676                         return -ENOENT;
1677                 }
1678
1679                 return 0;
1680         } else {
1681                 return btrfs_find_device_by_path(root, device_path, device);
1682         }
1683 }
1684
1685 /*
1686  * does all the dirty work required for changing file system's UUID.
1687  */
1688 static int btrfs_prepare_sprout(struct btrfs_root *root)
1689 {
1690         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1691         struct btrfs_fs_devices *old_devices;
1692         struct btrfs_fs_devices *seed_devices;
1693         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1694         struct btrfs_device *device;
1695         u64 super_flags;
1696
1697         BUG_ON(!mutex_is_locked(&uuid_mutex));
1698         if (!fs_devices->seeding)
1699                 return -EINVAL;
1700
1701         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1702         if (!seed_devices)
1703                 return -ENOMEM;
1704
1705         old_devices = clone_fs_devices(fs_devices);
1706         if (IS_ERR(old_devices)) {
1707                 kfree(seed_devices);
1708                 return PTR_ERR(old_devices);
1709         }
1710
1711         list_add(&old_devices->list, &fs_uuids);
1712
1713         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1714         seed_devices->opened = 1;
1715         INIT_LIST_HEAD(&seed_devices->devices);
1716         INIT_LIST_HEAD(&seed_devices->alloc_list);
1717         mutex_init(&seed_devices->device_list_mutex);
1718
1719         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1720         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1721                               synchronize_rcu);
1722         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1723
1724         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1725         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1726                 device->fs_devices = seed_devices;
1727         }
1728
1729         fs_devices->seeding = 0;
1730         fs_devices->num_devices = 0;
1731         fs_devices->open_devices = 0;
1732         fs_devices->total_devices = 0;
1733         fs_devices->seed = seed_devices;
1734
1735         generate_random_uuid(fs_devices->fsid);
1736         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1737         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1738         super_flags = btrfs_super_flags(disk_super) &
1739                       ~BTRFS_SUPER_FLAG_SEEDING;
1740         btrfs_set_super_flags(disk_super, super_flags);
1741
1742         return 0;
1743 }
1744
1745 /*
1746  * strore the expected generation for seed devices in device items.
1747  */
1748 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1749                                struct btrfs_root *root)
1750 {
1751         struct btrfs_path *path;
1752         struct extent_buffer *leaf;
1753         struct btrfs_dev_item *dev_item;
1754         struct btrfs_device *device;
1755         struct btrfs_key key;
1756         u8 fs_uuid[BTRFS_UUID_SIZE];
1757         u8 dev_uuid[BTRFS_UUID_SIZE];
1758         u64 devid;
1759         int ret;
1760
1761         path = btrfs_alloc_path();
1762         if (!path)
1763                 return -ENOMEM;
1764
1765         root = root->fs_info->chunk_root;
1766         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1767         key.offset = 0;
1768         key.type = BTRFS_DEV_ITEM_KEY;
1769
1770         while (1) {
1771                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1772                 if (ret < 0)
1773                         goto error;
1774
1775                 leaf = path->nodes[0];
1776 next_slot:
1777                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1778                         ret = btrfs_next_leaf(root, path);
1779                         if (ret > 0)
1780                                 break;
1781                         if (ret < 0)
1782                                 goto error;
1783                         leaf = path->nodes[0];
1784                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1785                         btrfs_release_path(path);
1786                         continue;
1787                 }
1788
1789                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1790                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1791                     key.type != BTRFS_DEV_ITEM_KEY)
1792                         break;
1793
1794                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1795                                           struct btrfs_dev_item);
1796                 devid = btrfs_device_id(leaf, dev_item);
1797                 read_extent_buffer(leaf, dev_uuid,
1798                                    (unsigned long)btrfs_device_uuid(dev_item),
1799                                    BTRFS_UUID_SIZE);
1800                 read_extent_buffer(leaf, fs_uuid,
1801                                    (unsigned long)btrfs_device_fsid(dev_item),
1802                                    BTRFS_UUID_SIZE);
1803                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1804                                            fs_uuid);
1805                 BUG_ON(!device); /* Logic error */
1806
1807                 if (device->fs_devices->seeding) {
1808                         btrfs_set_device_generation(leaf, dev_item,
1809                                                     device->generation);
1810                         btrfs_mark_buffer_dirty(leaf);
1811                 }
1812
1813                 path->slots[0]++;
1814                 goto next_slot;
1815         }
1816         ret = 0;
1817 error:
1818         btrfs_free_path(path);
1819         return ret;
1820 }
1821
1822 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1823 {
1824         struct request_queue *q;
1825         struct btrfs_trans_handle *trans;
1826         struct btrfs_device *device;
1827         struct block_device *bdev;
1828         struct list_head *devices;
1829         struct super_block *sb = root->fs_info->sb;
1830         struct rcu_string *name;
1831         u64 total_bytes;
1832         int seeding_dev = 0;
1833         int ret = 0;
1834
1835         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1836                 return -EROFS;
1837
1838         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1839                                   root->fs_info->bdev_holder);
1840         if (IS_ERR(bdev))
1841                 return PTR_ERR(bdev);
1842
1843         if (root->fs_info->fs_devices->seeding) {
1844                 seeding_dev = 1;
1845                 down_write(&sb->s_umount);
1846                 mutex_lock(&uuid_mutex);
1847         }
1848
1849         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1850
1851         devices = &root->fs_info->fs_devices->devices;
1852
1853         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1854         list_for_each_entry(device, devices, dev_list) {
1855                 if (device->bdev == bdev) {
1856                         ret = -EEXIST;
1857                         mutex_unlock(
1858                                 &root->fs_info->fs_devices->device_list_mutex);
1859                         goto error;
1860                 }
1861         }
1862         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1863
1864         device = kzalloc(sizeof(*device), GFP_NOFS);
1865         if (!device) {
1866                 /* we can safely leave the fs_devices entry around */
1867                 ret = -ENOMEM;
1868                 goto error;
1869         }
1870
1871         name = rcu_string_strdup(device_path, GFP_NOFS);
1872         if (!name) {
1873                 kfree(device);
1874                 ret = -ENOMEM;
1875                 goto error;
1876         }
1877         rcu_assign_pointer(device->name, name);
1878
1879         ret = find_next_devid(root, &device->devid);
1880         if (ret) {
1881                 rcu_string_free(device->name);
1882                 kfree(device);
1883                 goto error;
1884         }
1885
1886         trans = btrfs_start_transaction(root, 0);
1887         if (IS_ERR(trans)) {
1888                 rcu_string_free(device->name);
1889                 kfree(device);
1890                 ret = PTR_ERR(trans);
1891                 goto error;
1892         }
1893
1894         lock_chunks(root);
1895
1896         q = bdev_get_queue(bdev);
1897         if (blk_queue_discard(q))
1898                 device->can_discard = 1;
1899         device->writeable = 1;
1900         device->work.func = pending_bios_fn;
1901         generate_random_uuid(device->uuid);
1902         spin_lock_init(&device->io_lock);
1903         device->generation = trans->transid;
1904         device->io_width = root->sectorsize;
1905         device->io_align = root->sectorsize;
1906         device->sector_size = root->sectorsize;
1907         device->total_bytes = i_size_read(bdev->bd_inode);
1908         device->disk_total_bytes = device->total_bytes;
1909         device->dev_root = root->fs_info->dev_root;
1910         device->bdev = bdev;
1911         device->in_fs_metadata = 1;
1912         device->is_tgtdev_for_dev_replace = 0;
1913         device->mode = FMODE_EXCL;
1914         set_blocksize(device->bdev, 4096);
1915
1916         if (seeding_dev) {
1917                 sb->s_flags &= ~MS_RDONLY;
1918                 ret = btrfs_prepare_sprout(root);
1919                 BUG_ON(ret); /* -ENOMEM */
1920         }
1921
1922         device->fs_devices = root->fs_info->fs_devices;
1923
1924         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1925         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1926         list_add(&device->dev_alloc_list,
1927                  &root->fs_info->fs_devices->alloc_list);
1928         root->fs_info->fs_devices->num_devices++;
1929         root->fs_info->fs_devices->open_devices++;
1930         root->fs_info->fs_devices->rw_devices++;
1931         root->fs_info->fs_devices->total_devices++;
1932         if (device->can_discard)
1933                 root->fs_info->fs_devices->num_can_discard++;
1934         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1935
1936         spin_lock(&root->fs_info->free_chunk_lock);
1937         root->fs_info->free_chunk_space += device->total_bytes;
1938         spin_unlock(&root->fs_info->free_chunk_lock);
1939
1940         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1941                 root->fs_info->fs_devices->rotating = 1;
1942
1943         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1944         btrfs_set_super_total_bytes(root->fs_info->super_copy,
1945                                     total_bytes + device->total_bytes);
1946
1947         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1948         btrfs_set_super_num_devices(root->fs_info->super_copy,
1949                                     total_bytes + 1);
1950         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1951
1952         if (seeding_dev) {
1953                 ret = init_first_rw_device(trans, root, device);
1954                 if (ret) {
1955                         btrfs_abort_transaction(trans, root, ret);
1956                         goto error_trans;
1957                 }
1958                 ret = btrfs_finish_sprout(trans, root);
1959                 if (ret) {
1960                         btrfs_abort_transaction(trans, root, ret);
1961                         goto error_trans;
1962                 }
1963         } else {
1964                 ret = btrfs_add_device(trans, root, device);
1965                 if (ret) {
1966                         btrfs_abort_transaction(trans, root, ret);
1967                         goto error_trans;
1968                 }
1969         }
1970
1971         /*
1972          * we've got more storage, clear any full flags on the space
1973          * infos
1974          */
1975         btrfs_clear_space_info_full(root->fs_info);
1976
1977         unlock_chunks(root);
1978         root->fs_info->num_tolerated_disk_barrier_failures =
1979                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1980         ret = btrfs_commit_transaction(trans, root);
1981
1982         if (seeding_dev) {
1983                 mutex_unlock(&uuid_mutex);
1984                 up_write(&sb->s_umount);
1985
1986                 if (ret) /* transaction commit */
1987                         return ret;
1988
1989                 ret = btrfs_relocate_sys_chunks(root);
1990                 if (ret < 0)
1991                         btrfs_error(root->fs_info, ret,
1992                                     "Failed to relocate sys chunks after "
1993                                     "device initialization. This can be fixed "
1994                                     "using the \"btrfs balance\" command.");
1995                 trans = btrfs_attach_transaction(root);
1996                 if (IS_ERR(trans)) {
1997                         if (PTR_ERR(trans) == -ENOENT)
1998                                 return 0;
1999                         return PTR_ERR(trans);
2000                 }
2001                 ret = btrfs_commit_transaction(trans, root);
2002         }
2003
2004         return ret;
2005
2006 error_trans:
2007         unlock_chunks(root);
2008         btrfs_end_transaction(trans, root);
2009         rcu_string_free(device->name);
2010         kfree(device);
2011 error:
2012         blkdev_put(bdev, FMODE_EXCL);
2013         if (seeding_dev) {
2014                 mutex_unlock(&uuid_mutex);
2015                 up_write(&sb->s_umount);
2016         }
2017         return ret;
2018 }
2019
2020 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2021                                   struct btrfs_device **device_out)
2022 {
2023         struct request_queue *q;
2024         struct btrfs_device *device;
2025         struct block_device *bdev;
2026         struct btrfs_fs_info *fs_info = root->fs_info;
2027         struct list_head *devices;
2028         struct rcu_string *name;
2029         int ret = 0;
2030
2031         *device_out = NULL;
2032         if (fs_info->fs_devices->seeding)
2033                 return -EINVAL;
2034
2035         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2036                                   fs_info->bdev_holder);
2037         if (IS_ERR(bdev))
2038                 return PTR_ERR(bdev);
2039
2040         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2041
2042         devices = &fs_info->fs_devices->devices;
2043         list_for_each_entry(device, devices, dev_list) {
2044                 if (device->bdev == bdev) {
2045                         ret = -EEXIST;
2046                         goto error;
2047                 }
2048         }
2049
2050         device = kzalloc(sizeof(*device), GFP_NOFS);
2051         if (!device) {
2052                 ret = -ENOMEM;
2053                 goto error;
2054         }
2055
2056         name = rcu_string_strdup(device_path, GFP_NOFS);
2057         if (!name) {
2058                 kfree(device);
2059                 ret = -ENOMEM;
2060                 goto error;
2061         }
2062         rcu_assign_pointer(device->name, name);
2063
2064         q = bdev_get_queue(bdev);
2065         if (blk_queue_discard(q))
2066                 device->can_discard = 1;
2067         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2068         device->writeable = 1;
2069         device->work.func = pending_bios_fn;
2070         generate_random_uuid(device->uuid);
2071         device->devid = BTRFS_DEV_REPLACE_DEVID;
2072         spin_lock_init(&device->io_lock);
2073         device->generation = 0;
2074         device->io_width = root->sectorsize;
2075         device->io_align = root->sectorsize;
2076         device->sector_size = root->sectorsize;
2077         device->total_bytes = i_size_read(bdev->bd_inode);
2078         device->disk_total_bytes = device->total_bytes;
2079         device->dev_root = fs_info->dev_root;
2080         device->bdev = bdev;
2081         device->in_fs_metadata = 1;
2082         device->is_tgtdev_for_dev_replace = 1;
2083         device->mode = FMODE_EXCL;
2084         set_blocksize(device->bdev, 4096);
2085         device->fs_devices = fs_info->fs_devices;
2086         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2087         fs_info->fs_devices->num_devices++;
2088         fs_info->fs_devices->open_devices++;
2089         if (device->can_discard)
2090                 fs_info->fs_devices->num_can_discard++;
2091         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2092
2093         *device_out = device;
2094         return ret;
2095
2096 error:
2097         blkdev_put(bdev, FMODE_EXCL);
2098         return ret;
2099 }
2100
2101 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2102                                               struct btrfs_device *tgtdev)
2103 {
2104         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2105         tgtdev->io_width = fs_info->dev_root->sectorsize;
2106         tgtdev->io_align = fs_info->dev_root->sectorsize;
2107         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2108         tgtdev->dev_root = fs_info->dev_root;
2109         tgtdev->in_fs_metadata = 1;
2110 }
2111
2112 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2113                                         struct btrfs_device *device)
2114 {
2115         int ret;
2116         struct btrfs_path *path;
2117         struct btrfs_root *root;
2118         struct btrfs_dev_item *dev_item;
2119         struct extent_buffer *leaf;
2120         struct btrfs_key key;
2121
2122         root = device->dev_root->fs_info->chunk_root;
2123
2124         path = btrfs_alloc_path();
2125         if (!path)
2126                 return -ENOMEM;
2127
2128         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2129         key.type = BTRFS_DEV_ITEM_KEY;
2130         key.offset = device->devid;
2131
2132         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2133         if (ret < 0)
2134                 goto out;
2135
2136         if (ret > 0) {
2137                 ret = -ENOENT;
2138                 goto out;
2139         }
2140
2141         leaf = path->nodes[0];
2142         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2143
2144         btrfs_set_device_id(leaf, dev_item, device->devid);
2145         btrfs_set_device_type(leaf, dev_item, device->type);
2146         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2147         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2148         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2149         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
2150         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
2151         btrfs_mark_buffer_dirty(leaf);
2152
2153 out:
2154         btrfs_free_path(path);
2155         return ret;
2156 }
2157
2158 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
2159                       struct btrfs_device *device, u64 new_size)
2160 {
2161         struct btrfs_super_block *super_copy =
2162                 device->dev_root->fs_info->super_copy;
2163         u64 old_total = btrfs_super_total_bytes(super_copy);
2164         u64 diff = new_size - device->total_bytes;
2165
2166         if (!device->writeable)
2167                 return -EACCES;
2168         if (new_size <= device->total_bytes ||
2169             device->is_tgtdev_for_dev_replace)
2170                 return -EINVAL;
2171
2172         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2173         device->fs_devices->total_rw_bytes += diff;
2174
2175         device->total_bytes = new_size;
2176         device->disk_total_bytes = new_size;
2177         btrfs_clear_space_info_full(device->dev_root->fs_info);
2178
2179         return btrfs_update_device(trans, device);
2180 }
2181
2182 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2183                       struct btrfs_device *device, u64 new_size)
2184 {
2185         int ret;
2186         lock_chunks(device->dev_root);
2187         ret = __btrfs_grow_device(trans, device, new_size);
2188         unlock_chunks(device->dev_root);
2189         return ret;
2190 }
2191
2192 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2193                             struct btrfs_root *root,
2194                             u64 chunk_tree, u64 chunk_objectid,
2195                             u64 chunk_offset)
2196 {
2197         int ret;
2198         struct btrfs_path *path;
2199         struct btrfs_key key;
2200
2201         root = root->fs_info->chunk_root;
2202         path = btrfs_alloc_path();
2203         if (!path)
2204                 return -ENOMEM;
2205
2206         key.objectid = chunk_objectid;
2207         key.offset = chunk_offset;
2208         key.type = BTRFS_CHUNK_ITEM_KEY;
2209
2210         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2211         if (ret < 0)
2212                 goto out;
2213         else if (ret > 0) { /* Logic error or corruption */
2214                 btrfs_error(root->fs_info, -ENOENT,
2215                             "Failed lookup while freeing chunk.");
2216                 ret = -ENOENT;
2217                 goto out;
2218         }
2219
2220         ret = btrfs_del_item(trans, root, path);
2221         if (ret < 0)
2222                 btrfs_error(root->fs_info, ret,
2223                             "Failed to delete chunk item.");
2224 out:
2225         btrfs_free_path(path);
2226         return ret;
2227 }
2228
2229 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2230                         chunk_offset)
2231 {
2232         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2233         struct btrfs_disk_key *disk_key;
2234         struct btrfs_chunk *chunk;
2235         u8 *ptr;
2236         int ret = 0;
2237         u32 num_stripes;
2238         u32 array_size;
2239         u32 len = 0;
2240         u32 cur;
2241         struct btrfs_key key;
2242
2243         array_size = btrfs_super_sys_array_size(super_copy);
2244
2245         ptr = super_copy->sys_chunk_array;
2246         cur = 0;
2247
2248         while (cur < array_size) {
2249                 disk_key = (struct btrfs_disk_key *)ptr;
2250                 btrfs_disk_key_to_cpu(&key, disk_key);
2251
2252                 len = sizeof(*disk_key);
2253
2254                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2255                         chunk = (struct btrfs_chunk *)(ptr + len);
2256                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2257                         len += btrfs_chunk_item_size(num_stripes);
2258                 } else {
2259                         ret = -EIO;
2260                         break;
2261                 }
2262                 if (key.objectid == chunk_objectid &&
2263                     key.offset == chunk_offset) {
2264                         memmove(ptr, ptr + len, array_size - (cur + len));
2265                         array_size -= len;
2266                         btrfs_set_super_sys_array_size(super_copy, array_size);
2267                 } else {
2268                         ptr += len;
2269                         cur += len;
2270                 }
2271         }
2272         return ret;
2273 }
2274
2275 static int btrfs_relocate_chunk(struct btrfs_root *root,
2276                          u64 chunk_tree, u64 chunk_objectid,
2277                          u64 chunk_offset)
2278 {
2279         struct extent_map_tree *em_tree;
2280         struct btrfs_root *extent_root;
2281         struct btrfs_trans_handle *trans;
2282         struct extent_map *em;
2283         struct map_lookup *map;
2284         int ret;
2285         int i;
2286
2287         root = root->fs_info->chunk_root;
2288         extent_root = root->fs_info->extent_root;
2289         em_tree = &root->fs_info->mapping_tree.map_tree;
2290
2291         ret = btrfs_can_relocate(extent_root, chunk_offset);
2292         if (ret)
2293                 return -ENOSPC;
2294
2295         /* step one, relocate all the extents inside this chunk */
2296         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2297         if (ret)
2298                 return ret;
2299
2300         trans = btrfs_start_transaction(root, 0);
2301         BUG_ON(IS_ERR(trans));
2302
2303         lock_chunks(root);
2304
2305         /*
2306          * step two, delete the device extents and the
2307          * chunk tree entries
2308          */
2309         read_lock(&em_tree->lock);
2310         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2311         read_unlock(&em_tree->lock);
2312
2313         BUG_ON(!em || em->start > chunk_offset ||
2314                em->start + em->len < chunk_offset);
2315         map = (struct map_lookup *)em->bdev;
2316
2317         for (i = 0; i < map->num_stripes; i++) {
2318                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2319                                             map->stripes[i].physical);
2320                 BUG_ON(ret);
2321
2322                 if (map->stripes[i].dev) {
2323                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2324                         BUG_ON(ret);
2325                 }
2326         }
2327         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2328                                chunk_offset);
2329
2330         BUG_ON(ret);
2331
2332         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2333
2334         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2335                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2336                 BUG_ON(ret);
2337         }
2338
2339         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2340         BUG_ON(ret);
2341
2342         write_lock(&em_tree->lock);
2343         remove_extent_mapping(em_tree, em);
2344         write_unlock(&em_tree->lock);
2345
2346         kfree(map);
2347         em->bdev = NULL;
2348
2349         /* once for the tree */
2350         free_extent_map(em);
2351         /* once for us */
2352         free_extent_map(em);
2353
2354         unlock_chunks(root);
2355         btrfs_end_transaction(trans, root);
2356         return 0;
2357 }
2358
2359 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2360 {
2361         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2362         struct btrfs_path *path;
2363         struct extent_buffer *leaf;
2364         struct btrfs_chunk *chunk;
2365         struct btrfs_key key;
2366         struct btrfs_key found_key;
2367         u64 chunk_tree = chunk_root->root_key.objectid;
2368         u64 chunk_type;
2369         bool retried = false;
2370         int failed = 0;
2371         int ret;
2372
2373         path = btrfs_alloc_path();
2374         if (!path)
2375                 return -ENOMEM;
2376
2377 again:
2378         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2379         key.offset = (u64)-1;
2380         key.type = BTRFS_CHUNK_ITEM_KEY;
2381
2382         while (1) {
2383                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2384                 if (ret < 0)
2385                         goto error;
2386                 BUG_ON(ret == 0); /* Corruption */
2387
2388                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2389                                           key.type);
2390                 if (ret < 0)
2391                         goto error;
2392                 if (ret > 0)
2393                         break;
2394
2395                 leaf = path->nodes[0];
2396                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2397
2398                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2399                                        struct btrfs_chunk);
2400                 chunk_type = btrfs_chunk_type(leaf, chunk);
2401                 btrfs_release_path(path);
2402
2403                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2404                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2405                                                    found_key.objectid,
2406                                                    found_key.offset);
2407                         if (ret == -ENOSPC)
2408                                 failed++;
2409                         else if (ret)
2410                                 BUG();
2411                 }
2412
2413                 if (found_key.offset == 0)
2414                         break;
2415                 key.offset = found_key.offset - 1;
2416         }
2417         ret = 0;
2418         if (failed && !retried) {
2419                 failed = 0;
2420                 retried = true;
2421                 goto again;
2422         } else if (failed && retried) {
2423                 WARN_ON(1);
2424                 ret = -ENOSPC;
2425         }
2426 error:
2427         btrfs_free_path(path);
2428         return ret;
2429 }
2430
2431 static int insert_balance_item(struct btrfs_root *root,
2432                                struct btrfs_balance_control *bctl)
2433 {
2434         struct btrfs_trans_handle *trans;
2435         struct btrfs_balance_item *item;
2436         struct btrfs_disk_balance_args disk_bargs;
2437         struct btrfs_path *path;
2438         struct extent_buffer *leaf;
2439         struct btrfs_key key;
2440         int ret, err;
2441
2442         path = btrfs_alloc_path();
2443         if (!path)
2444                 return -ENOMEM;
2445
2446         trans = btrfs_start_transaction(root, 0);
2447         if (IS_ERR(trans)) {
2448                 btrfs_free_path(path);
2449                 return PTR_ERR(trans);
2450         }
2451
2452         key.objectid = BTRFS_BALANCE_OBJECTID;
2453         key.type = BTRFS_BALANCE_ITEM_KEY;
2454         key.offset = 0;
2455
2456         ret = btrfs_insert_empty_item(trans, root, path, &key,
2457                                       sizeof(*item));
2458         if (ret)
2459                 goto out;
2460
2461         leaf = path->nodes[0];
2462         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2463
2464         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2465
2466         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2467         btrfs_set_balance_data(leaf, item, &disk_bargs);
2468         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2469         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2470         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2471         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2472
2473         btrfs_set_balance_flags(leaf, item, bctl->flags);
2474
2475         btrfs_mark_buffer_dirty(leaf);
2476 out:
2477         btrfs_free_path(path);
2478         err = btrfs_commit_transaction(trans, root);
2479         if (err && !ret)
2480                 ret = err;
2481         return ret;
2482 }
2483
2484 static int del_balance_item(struct btrfs_root *root)
2485 {
2486         struct btrfs_trans_handle *trans;
2487         struct btrfs_path *path;
2488         struct btrfs_key key;
2489         int ret, err;
2490
2491         path = btrfs_alloc_path();
2492         if (!path)
2493                 return -ENOMEM;
2494
2495         trans = btrfs_start_transaction(root, 0);
2496         if (IS_ERR(trans)) {
2497                 btrfs_free_path(path);
2498                 return PTR_ERR(trans);
2499         }
2500
2501         key.objectid = BTRFS_BALANCE_OBJECTID;
2502         key.type = BTRFS_BALANCE_ITEM_KEY;
2503         key.offset = 0;
2504
2505         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2506         if (ret < 0)
2507                 goto out;
2508         if (ret > 0) {
2509                 ret = -ENOENT;
2510                 goto out;
2511         }
2512
2513         ret = btrfs_del_item(trans, root, path);
2514 out:
2515         btrfs_free_path(path);
2516         err = btrfs_commit_transaction(trans, root);
2517         if (err && !ret)
2518                 ret = err;
2519         return ret;
2520 }
2521
2522 /*
2523  * This is a heuristic used to reduce the number of chunks balanced on
2524  * resume after balance was interrupted.
2525  */
2526 static void update_balance_args(struct btrfs_balance_control *bctl)
2527 {
2528         /*
2529          * Turn on soft mode for chunk types that were being converted.
2530          */
2531         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2532                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2533         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2534                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2535         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2536                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2537
2538         /*
2539          * Turn on usage filter if is not already used.  The idea is
2540          * that chunks that we have already balanced should be
2541          * reasonably full.  Don't do it for chunks that are being
2542          * converted - that will keep us from relocating unconverted
2543          * (albeit full) chunks.
2544          */
2545         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2546             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2547                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2548                 bctl->data.usage = 90;
2549         }
2550         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2551             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2552                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2553                 bctl->sys.usage = 90;
2554         }
2555         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2556             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2557                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2558                 bctl->meta.usage = 90;
2559         }
2560 }
2561
2562 /*
2563  * Should be called with both balance and volume mutexes held to
2564  * serialize other volume operations (add_dev/rm_dev/resize) with
2565  * restriper.  Same goes for unset_balance_control.
2566  */
2567 static void set_balance_control(struct btrfs_balance_control *bctl)
2568 {
2569         struct btrfs_fs_info *fs_info = bctl->fs_info;
2570
2571         BUG_ON(fs_info->balance_ctl);
2572
2573         spin_lock(&fs_info->balance_lock);
2574         fs_info->balance_ctl = bctl;
2575         spin_unlock(&fs_info->balance_lock);
2576 }
2577
2578 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2579 {
2580         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2581
2582         BUG_ON(!fs_info->balance_ctl);
2583
2584         spin_lock(&fs_info->balance_lock);
2585         fs_info->balance_ctl = NULL;
2586         spin_unlock(&fs_info->balance_lock);
2587
2588         kfree(bctl);
2589 }
2590
2591 /*
2592  * Balance filters.  Return 1 if chunk should be filtered out
2593  * (should not be balanced).
2594  */
2595 static int chunk_profiles_filter(u64 chunk_type,
2596                                  struct btrfs_balance_args *bargs)
2597 {
2598         chunk_type = chunk_to_extended(chunk_type) &
2599                                 BTRFS_EXTENDED_PROFILE_MASK;
2600
2601         if (bargs->profiles & chunk_type)
2602                 return 0;
2603
2604         return 1;
2605 }
2606
2607 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2608                               struct btrfs_balance_args *bargs)
2609 {
2610         struct btrfs_block_group_cache *cache;
2611         u64 chunk_used, user_thresh;
2612         int ret = 1;
2613
2614         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2615         chunk_used = btrfs_block_group_used(&cache->item);
2616
2617         user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
2618         if (chunk_used < user_thresh)
2619                 ret = 0;
2620
2621         btrfs_put_block_group(cache);
2622         return ret;
2623 }
2624
2625 static int chunk_devid_filter(struct extent_buffer *leaf,
2626                               struct btrfs_chunk *chunk,
2627                               struct btrfs_balance_args *bargs)
2628 {
2629         struct btrfs_stripe *stripe;
2630         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2631         int i;
2632
2633         for (i = 0; i < num_stripes; i++) {
2634                 stripe = btrfs_stripe_nr(chunk, i);
2635                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2636                         return 0;
2637         }
2638
2639         return 1;
2640 }
2641
2642 /* [pstart, pend) */
2643 static int chunk_drange_filter(struct extent_buffer *leaf,
2644                                struct btrfs_chunk *chunk,
2645                                u64 chunk_offset,
2646                                struct btrfs_balance_args *bargs)
2647 {
2648         struct btrfs_stripe *stripe;
2649         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2650         u64 stripe_offset;
2651         u64 stripe_length;
2652         int factor;
2653         int i;
2654
2655         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2656                 return 0;
2657
2658         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2659              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
2660                 factor = 2;
2661         else
2662                 factor = 1;
2663         factor = num_stripes / factor;
2664
2665         for (i = 0; i < num_stripes; i++) {
2666                 stripe = btrfs_stripe_nr(chunk, i);
2667                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2668                         continue;
2669
2670                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2671                 stripe_length = btrfs_chunk_length(leaf, chunk);
2672                 do_div(stripe_length, factor);
2673
2674                 if (stripe_offset < bargs->pend &&
2675                     stripe_offset + stripe_length > bargs->pstart)
2676                         return 0;
2677         }
2678
2679         return 1;
2680 }
2681
2682 /* [vstart, vend) */
2683 static int chunk_vrange_filter(struct extent_buffer *leaf,
2684                                struct btrfs_chunk *chunk,
2685                                u64 chunk_offset,
2686                                struct btrfs_balance_args *bargs)
2687 {
2688         if (chunk_offset < bargs->vend &&
2689             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2690                 /* at least part of the chunk is inside this vrange */
2691                 return 0;
2692
2693         return 1;
2694 }
2695
2696 static int chunk_soft_convert_filter(u64 chunk_type,
2697                                      struct btrfs_balance_args *bargs)
2698 {
2699         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2700                 return 0;
2701
2702         chunk_type = chunk_to_extended(chunk_type) &
2703                                 BTRFS_EXTENDED_PROFILE_MASK;
2704
2705         if (bargs->target == chunk_type)
2706                 return 1;
2707
2708         return 0;
2709 }
2710
2711 static int should_balance_chunk(struct btrfs_root *root,
2712                                 struct extent_buffer *leaf,
2713                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2714 {
2715         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2716         struct btrfs_balance_args *bargs = NULL;
2717         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2718
2719         /* type filter */
2720         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2721               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2722                 return 0;
2723         }
2724
2725         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2726                 bargs = &bctl->data;
2727         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2728                 bargs = &bctl->sys;
2729         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2730                 bargs = &bctl->meta;
2731
2732         /* profiles filter */
2733         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2734             chunk_profiles_filter(chunk_type, bargs)) {
2735                 return 0;
2736         }
2737
2738         /* usage filter */
2739         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2740             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2741                 return 0;
2742         }
2743
2744         /* devid filter */
2745         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2746             chunk_devid_filter(leaf, chunk, bargs)) {
2747                 return 0;
2748         }
2749
2750         /* drange filter, makes sense only with devid filter */
2751         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2752             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2753                 return 0;
2754         }
2755
2756         /* vrange filter */
2757         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2758             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2759                 return 0;
2760         }
2761
2762         /* soft profile changing mode */
2763         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2764             chunk_soft_convert_filter(chunk_type, bargs)) {
2765                 return 0;
2766         }
2767
2768         return 1;
2769 }
2770
2771 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2772 {
2773         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2774         struct btrfs_root *chunk_root = fs_info->chunk_root;
2775         struct btrfs_root *dev_root = fs_info->dev_root;
2776         struct list_head *devices;
2777         struct btrfs_device *device;
2778         u64 old_size;
2779         u64 size_to_free;
2780         struct btrfs_chunk *chunk;
2781         struct btrfs_path *path;
2782         struct btrfs_key key;
2783         struct btrfs_key found_key;
2784         struct btrfs_trans_handle *trans;
2785         struct extent_buffer *leaf;
2786         int slot;
2787         int ret;
2788         int enospc_errors = 0;
2789         bool counting = true;
2790
2791         /* step one make some room on all the devices */
2792         devices = &fs_info->fs_devices->devices;
2793         list_for_each_entry(device, devices, dev_list) {
2794                 old_size = device->total_bytes;
2795                 size_to_free = div_factor(old_size, 1);
2796                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2797                 if (!device->writeable ||
2798                     device->total_bytes - device->bytes_used > size_to_free ||
2799                     device->is_tgtdev_for_dev_replace)
2800                         continue;
2801
2802                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2803                 if (ret == -ENOSPC)
2804                         break;
2805                 BUG_ON(ret);
2806
2807                 trans = btrfs_start_transaction(dev_root, 0);
2808                 BUG_ON(IS_ERR(trans));
2809
2810                 ret = btrfs_grow_device(trans, device, old_size);
2811                 BUG_ON(ret);
2812
2813                 btrfs_end_transaction(trans, dev_root);
2814         }
2815
2816         /* step two, relocate all the chunks */
2817         path = btrfs_alloc_path();
2818         if (!path) {
2819                 ret = -ENOMEM;
2820                 goto error;
2821         }
2822
2823         /* zero out stat counters */
2824         spin_lock(&fs_info->balance_lock);
2825         memset(&bctl->stat, 0, sizeof(bctl->stat));
2826         spin_unlock(&fs_info->balance_lock);
2827 again:
2828         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2829         key.offset = (u64)-1;
2830         key.type = BTRFS_CHUNK_ITEM_KEY;
2831
2832         while (1) {
2833                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2834                     atomic_read(&fs_info->balance_cancel_req)) {
2835                         ret = -ECANCELED;
2836                         goto error;
2837                 }
2838
2839                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2840                 if (ret < 0)
2841                         goto error;
2842
2843                 /*
2844                  * this shouldn't happen, it means the last relocate
2845                  * failed
2846                  */
2847                 if (ret == 0)
2848                         BUG(); /* FIXME break ? */
2849
2850                 ret = btrfs_previous_item(chunk_root, path, 0,
2851                                           BTRFS_CHUNK_ITEM_KEY);
2852                 if (ret) {
2853                         ret = 0;
2854                         break;
2855                 }
2856
2857                 leaf = path->nodes[0];
2858                 slot = path->slots[0];
2859                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2860
2861                 if (found_key.objectid != key.objectid)
2862                         break;
2863
2864                 /* chunk zero is special */
2865                 if (found_key.offset == 0)
2866                         break;
2867
2868                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2869
2870                 if (!counting) {
2871                         spin_lock(&fs_info->balance_lock);
2872                         bctl->stat.considered++;
2873                         spin_unlock(&fs_info->balance_lock);
2874                 }
2875
2876                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2877                                            found_key.offset);
2878                 btrfs_release_path(path);
2879                 if (!ret)
2880                         goto loop;
2881
2882                 if (counting) {
2883                         spin_lock(&fs_info->balance_lock);
2884                         bctl->stat.expected++;
2885                         spin_unlock(&fs_info->balance_lock);
2886                         goto loop;
2887                 }
2888
2889                 ret = btrfs_relocate_chunk(chunk_root,
2890                                            chunk_root->root_key.objectid,
2891                                            found_key.objectid,
2892                                            found_key.offset);
2893                 if (ret && ret != -ENOSPC)
2894                         goto error;
2895                 if (ret == -ENOSPC) {
2896                         enospc_errors++;
2897                 } else {
2898                         spin_lock(&fs_info->balance_lock);
2899                         bctl->stat.completed++;
2900                         spin_unlock(&fs_info->balance_lock);
2901                 }
2902 loop:
2903                 key.offset = found_key.offset - 1;
2904         }
2905
2906         if (counting) {
2907                 btrfs_release_path(path);
2908                 counting = false;
2909                 goto again;
2910         }
2911 error:
2912         btrfs_free_path(path);
2913         if (enospc_errors) {
2914                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2915                        enospc_errors);
2916                 if (!ret)
2917                         ret = -ENOSPC;
2918         }
2919
2920         return ret;
2921 }
2922
2923 /**
2924  * alloc_profile_is_valid - see if a given profile is valid and reduced
2925  * @flags: profile to validate
2926  * @extended: if true @flags is treated as an extended profile
2927  */
2928 static int alloc_profile_is_valid(u64 flags, int extended)
2929 {
2930         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
2931                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
2932
2933         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
2934
2935         /* 1) check that all other bits are zeroed */
2936         if (flags & ~mask)
2937                 return 0;
2938
2939         /* 2) see if profile is reduced */
2940         if (flags == 0)
2941                 return !extended; /* "0" is valid for usual profiles */
2942
2943         /* true if exactly one bit set */
2944         return (flags & (flags - 1)) == 0;
2945 }
2946
2947 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
2948 {
2949         /* cancel requested || normal exit path */
2950         return atomic_read(&fs_info->balance_cancel_req) ||
2951                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
2952                  atomic_read(&fs_info->balance_cancel_req) == 0);
2953 }
2954
2955 static void __cancel_balance(struct btrfs_fs_info *fs_info)
2956 {
2957         int ret;
2958
2959         unset_balance_control(fs_info);
2960         ret = del_balance_item(fs_info->tree_root);
2961         BUG_ON(ret);
2962 }
2963
2964 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
2965                                struct btrfs_ioctl_balance_args *bargs);
2966
2967 /*
2968  * Should be called with both balance and volume mutexes held
2969  */
2970 int btrfs_balance(struct btrfs_balance_control *bctl,
2971                   struct btrfs_ioctl_balance_args *bargs)
2972 {
2973         struct btrfs_fs_info *fs_info = bctl->fs_info;
2974         u64 allowed;
2975         int mixed = 0;
2976         int ret;
2977         u64 num_devices;
2978
2979         if (btrfs_fs_closing(fs_info) ||
2980             atomic_read(&fs_info->balance_pause_req) ||
2981             atomic_read(&fs_info->balance_cancel_req)) {
2982                 ret = -EINVAL;
2983                 goto out;
2984         }
2985
2986         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2987         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
2988                 mixed = 1;
2989
2990         /*
2991          * In case of mixed groups both data and meta should be picked,
2992          * and identical options should be given for both of them.
2993          */
2994         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
2995         if (mixed && (bctl->flags & allowed)) {
2996                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
2997                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
2998                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
2999                         printk(KERN_ERR "btrfs: with mixed groups data and "
3000                                "metadata balance options must be the same\n");
3001                         ret = -EINVAL;
3002                         goto out;
3003                 }
3004         }
3005
3006         num_devices = fs_info->fs_devices->num_devices;
3007         btrfs_dev_replace_lock(&fs_info->dev_replace);
3008         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3009                 BUG_ON(num_devices < 1);
3010                 num_devices--;
3011         }
3012         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3013         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3014         if (num_devices == 1)
3015                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3016         else if (num_devices < 4)
3017                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3018         else
3019                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
3020                                 BTRFS_BLOCK_GROUP_RAID10);
3021
3022         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3023             (!alloc_profile_is_valid(bctl->data.target, 1) ||
3024              (bctl->data.target & ~allowed))) {
3025                 printk(KERN_ERR "btrfs: unable to start balance with target "
3026                        "data profile %llu\n",
3027                        (unsigned long long)bctl->data.target);
3028                 ret = -EINVAL;
3029                 goto out;
3030         }
3031         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3032             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
3033              (bctl->meta.target & ~allowed))) {
3034                 printk(KERN_ERR "btrfs: unable to start balance with target "
3035                        "metadata profile %llu\n",
3036                        (unsigned long long)bctl->meta.target);
3037                 ret = -EINVAL;
3038                 goto out;
3039         }
3040         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3041             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
3042              (bctl->sys.target & ~allowed))) {
3043                 printk(KERN_ERR "btrfs: unable to start balance with target "
3044                        "system profile %llu\n",
3045                        (unsigned long long)bctl->sys.target);
3046                 ret = -EINVAL;
3047                 goto out;
3048         }
3049
3050         /* allow dup'ed data chunks only in mixed mode */
3051         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3052             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3053                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
3054                 ret = -EINVAL;
3055                 goto out;
3056         }
3057
3058         /* allow to reduce meta or sys integrity only if force set */
3059         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3060                         BTRFS_BLOCK_GROUP_RAID10;
3061         if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3062              (fs_info->avail_system_alloc_bits & allowed) &&
3063              !(bctl->sys.target & allowed)) ||
3064             ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3065              (fs_info->avail_metadata_alloc_bits & allowed) &&
3066              !(bctl->meta.target & allowed))) {
3067                 if (bctl->flags & BTRFS_BALANCE_FORCE) {
3068                         printk(KERN_INFO "btrfs: force reducing metadata "
3069                                "integrity\n");
3070                 } else {
3071                         printk(KERN_ERR "btrfs: balance will reduce metadata "
3072                                "integrity, use force if you want this\n");
3073                         ret = -EINVAL;
3074                         goto out;
3075                 }
3076         }
3077
3078         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3079                 int num_tolerated_disk_barrier_failures;
3080                 u64 target = bctl->sys.target;
3081
3082                 num_tolerated_disk_barrier_failures =
3083                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3084                 if (num_tolerated_disk_barrier_failures > 0 &&
3085                     (target &
3086                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3087                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
3088                         num_tolerated_disk_barrier_failures = 0;
3089                 else if (num_tolerated_disk_barrier_failures > 1 &&
3090                          (target &
3091                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
3092                         num_tolerated_disk_barrier_failures = 1;
3093
3094                 fs_info->num_tolerated_disk_barrier_failures =
3095                         num_tolerated_disk_barrier_failures;
3096         }
3097
3098         ret = insert_balance_item(fs_info->tree_root, bctl);
3099         if (ret && ret != -EEXIST)
3100                 goto out;
3101
3102         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3103                 BUG_ON(ret == -EEXIST);
3104                 set_balance_control(bctl);
3105         } else {
3106                 BUG_ON(ret != -EEXIST);
3107                 spin_lock(&fs_info->balance_lock);
3108                 update_balance_args(bctl);
3109                 spin_unlock(&fs_info->balance_lock);
3110         }
3111
3112         atomic_inc(&fs_info->balance_running);
3113         mutex_unlock(&fs_info->balance_mutex);
3114
3115         ret = __btrfs_balance(fs_info);
3116
3117         mutex_lock(&fs_info->balance_mutex);
3118         atomic_dec(&fs_info->balance_running);
3119
3120         if (bargs) {
3121                 memset(bargs, 0, sizeof(*bargs));
3122                 update_ioctl_balance_args(fs_info, 0, bargs);
3123         }
3124
3125         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3126             balance_need_close(fs_info)) {
3127                 __cancel_balance(fs_info);
3128         }
3129
3130         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3131                 fs_info->num_tolerated_disk_barrier_failures =
3132                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3133         }
3134
3135         wake_up(&fs_info->balance_wait_q);
3136
3137         return ret;
3138 out:
3139         if (bctl->flags & BTRFS_BALANCE_RESUME)
3140                 __cancel_balance(fs_info);
3141         else
3142                 kfree(bctl);
3143         return ret;
3144 }
3145
3146 static int balance_kthread(void *data)
3147 {
3148         struct btrfs_fs_info *fs_info = data;
3149         int ret = 0;
3150
3151         mutex_lock(&fs_info->volume_mutex);
3152         mutex_lock(&fs_info->balance_mutex);
3153
3154         if (fs_info->balance_ctl) {
3155                 printk(KERN_INFO "btrfs: continuing balance\n");
3156                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3157         }
3158
3159         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3160         mutex_unlock(&fs_info->balance_mutex);
3161         mutex_unlock(&fs_info->volume_mutex);
3162
3163         return ret;
3164 }
3165
3166 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3167 {
3168         struct task_struct *tsk;
3169
3170         spin_lock(&fs_info->balance_lock);
3171         if (!fs_info->balance_ctl) {
3172                 spin_unlock(&fs_info->balance_lock);
3173                 return 0;
3174         }
3175         spin_unlock(&fs_info->balance_lock);
3176
3177         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3178                 printk(KERN_INFO "btrfs: force skipping balance\n");
3179                 return 0;
3180         }
3181
3182         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3183         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3184         if (IS_ERR(tsk))
3185                 return PTR_ERR(tsk);
3186
3187         return 0;
3188 }
3189
3190 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3191 {
3192         struct btrfs_balance_control *bctl;
3193         struct btrfs_balance_item *item;
3194         struct btrfs_disk_balance_args disk_bargs;
3195         struct btrfs_path *path;
3196         struct extent_buffer *leaf;
3197         struct btrfs_key key;
3198         int ret;
3199
3200         path = btrfs_alloc_path();
3201         if (!path)
3202                 return -ENOMEM;
3203
3204         key.objectid = BTRFS_BALANCE_OBJECTID;
3205         key.type = BTRFS_BALANCE_ITEM_KEY;
3206         key.offset = 0;
3207
3208         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3209         if (ret < 0)
3210                 goto out;
3211         if (ret > 0) { /* ret = -ENOENT; */
3212                 ret = 0;
3213                 goto out;
3214         }
3215
3216         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3217         if (!bctl) {
3218                 ret = -ENOMEM;
3219                 goto out;
3220         }
3221
3222         leaf = path->nodes[0];
3223         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3224
3225         bctl->fs_info = fs_info;
3226         bctl->flags = btrfs_balance_flags(leaf, item);
3227         bctl->flags |= BTRFS_BALANCE_RESUME;
3228
3229         btrfs_balance_data(leaf, item, &disk_bargs);
3230         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3231         btrfs_balance_meta(leaf, item, &disk_bargs);
3232         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3233         btrfs_balance_sys(leaf, item, &disk_bargs);
3234         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3235
3236         mutex_lock(&fs_info->volume_mutex);
3237         mutex_lock(&fs_info->balance_mutex);
3238
3239         set_balance_control(bctl);
3240
3241         mutex_unlock(&fs_info->balance_mutex);
3242         mutex_unlock(&fs_info->volume_mutex);
3243 out:
3244         btrfs_free_path(path);
3245         return ret;
3246 }
3247
3248 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3249 {
3250         int ret = 0;
3251
3252         mutex_lock(&fs_info->balance_mutex);
3253         if (!fs_info->balance_ctl) {
3254                 mutex_unlock(&fs_info->balance_mutex);
3255                 return -ENOTCONN;
3256         }
3257
3258         if (atomic_read(&fs_info->balance_running)) {
3259                 atomic_inc(&fs_info->balance_pause_req);
3260                 mutex_unlock(&fs_info->balance_mutex);
3261
3262                 wait_event(fs_info->balance_wait_q,
3263                            atomic_read(&fs_info->balance_running) == 0);
3264
3265                 mutex_lock(&fs_info->balance_mutex);
3266                 /* we are good with balance_ctl ripped off from under us */
3267                 BUG_ON(atomic_read(&fs_info->balance_running));
3268                 atomic_dec(&fs_info->balance_pause_req);
3269         } else {
3270                 ret = -ENOTCONN;
3271         }
3272
3273         mutex_unlock(&fs_info->balance_mutex);
3274         return ret;
3275 }
3276
3277 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3278 {
3279         mutex_lock(&fs_info->balance_mutex);
3280         if (!fs_info->balance_ctl) {
3281                 mutex_unlock(&fs_info->balance_mutex);
3282                 return -ENOTCONN;
3283         }
3284
3285         atomic_inc(&fs_info->balance_cancel_req);
3286         /*
3287          * if we are running just wait and return, balance item is
3288          * deleted in btrfs_balance in this case
3289          */
3290         if (atomic_read(&fs_info->balance_running)) {
3291                 mutex_unlock(&fs_info->balance_mutex);
3292                 wait_event(fs_info->balance_wait_q,
3293                            atomic_read(&fs_info->balance_running) == 0);
3294                 mutex_lock(&fs_info->balance_mutex);
3295         } else {
3296                 /* __cancel_balance needs volume_mutex */
3297                 mutex_unlock(&fs_info->balance_mutex);
3298                 mutex_lock(&fs_info->volume_mutex);
3299                 mutex_lock(&fs_info->balance_mutex);
3300
3301                 if (fs_info->balance_ctl)
3302                         __cancel_balance(fs_info);
3303
3304                 mutex_unlock(&fs_info->volume_mutex);
3305         }
3306
3307         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3308         atomic_dec(&fs_info->balance_cancel_req);
3309         mutex_unlock(&fs_info->balance_mutex);
3310         return 0;
3311 }
3312
3313 /*
3314  * shrinking a device means finding all of the device extents past
3315  * the new size, and then following the back refs to the chunks.
3316  * The chunk relocation code actually frees the device extent
3317  */
3318 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3319 {
3320         struct btrfs_trans_handle *trans;
3321         struct btrfs_root *root = device->dev_root;
3322         struct btrfs_dev_extent *dev_extent = NULL;
3323         struct btrfs_path *path;
3324         u64 length;
3325         u64 chunk_tree;
3326         u64 chunk_objectid;
3327         u64 chunk_offset;
3328         int ret;
3329         int slot;
3330         int failed = 0;
3331         bool retried = false;
3332         struct extent_buffer *l;
3333         struct btrfs_key key;
3334         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3335         u64 old_total = btrfs_super_total_bytes(super_copy);
3336         u64 old_size = device->total_bytes;
3337         u64 diff = device->total_bytes - new_size;
3338
3339         if (device->is_tgtdev_for_dev_replace)
3340                 return -EINVAL;
3341
3342         path = btrfs_alloc_path();
3343         if (!path)
3344                 return -ENOMEM;
3345
3346         path->reada = 2;
3347
3348         lock_chunks(root);
3349
3350         device->total_bytes = new_size;
3351         if (device->writeable) {
3352                 device->fs_devices->total_rw_bytes -= diff;
3353                 spin_lock(&root->fs_info->free_chunk_lock);
3354                 root->fs_info->free_chunk_space -= diff;
3355                 spin_unlock(&root->fs_info->free_chunk_lock);
3356         }
3357         unlock_chunks(root);
3358
3359 again:
3360         key.objectid = device->devid;
3361         key.offset = (u64)-1;
3362         key.type = BTRFS_DEV_EXTENT_KEY;
3363
3364         do {
3365                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3366                 if (ret < 0)
3367                         goto done;
3368
3369                 ret = btrfs_previous_item(root, path, 0, key.type);
3370                 if (ret < 0)
3371                         goto done;
3372                 if (ret) {
3373                         ret = 0;
3374                         btrfs_release_path(path);
3375                         break;
3376                 }
3377
3378                 l = path->nodes[0];
3379                 slot = path->slots[0];
3380                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3381
3382                 if (key.objectid != device->devid) {
3383                         btrfs_release_path(path);
3384                         break;
3385                 }
3386
3387                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3388                 length = btrfs_dev_extent_length(l, dev_extent);
3389
3390                 if (key.offset + length <= new_size) {
3391                         btrfs_release_path(path);
3392                         break;
3393                 }
3394
3395                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3396                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3397                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3398                 btrfs_release_path(path);
3399
3400                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3401                                            chunk_offset);
3402                 if (ret && ret != -ENOSPC)
3403                         goto done;
3404                 if (ret == -ENOSPC)
3405                         failed++;
3406         } while (key.offset-- > 0);
3407
3408         if (failed && !retried) {
3409                 failed = 0;
3410                 retried = true;
3411                 goto again;
3412         } else if (failed && retried) {
3413                 ret = -ENOSPC;
3414                 lock_chunks(root);
3415
3416                 device->total_bytes = old_size;
3417                 if (device->writeable)
3418                         device->fs_devices->total_rw_bytes += diff;
3419                 spin_lock(&root->fs_info->free_chunk_lock);
3420                 root->fs_info->free_chunk_space += diff;
3421                 spin_unlock(&root->fs_info->free_chunk_lock);
3422                 unlock_chunks(root);
3423                 goto done;
3424         }
3425
3426         /* Shrinking succeeded, else we would be at "done". */
3427         trans = btrfs_start_transaction(root, 0);
3428         if (IS_ERR(trans)) {
3429                 ret = PTR_ERR(trans);
3430                 goto done;
3431         }
3432
3433         lock_chunks(root);
3434
3435         device->disk_total_bytes = new_size;
3436         /* Now btrfs_update_device() will change the on-disk size. */
3437         ret = btrfs_update_device(trans, device);
3438         if (ret) {
3439                 unlock_chunks(root);
3440                 btrfs_end_transaction(trans, root);
3441                 goto done;
3442         }
3443         WARN_ON(diff > old_total);
3444         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3445         unlock_chunks(root);
3446         btrfs_end_transaction(trans, root);
3447 done:
3448         btrfs_free_path(path);
3449         return ret;
3450 }
3451
3452 static int btrfs_add_system_chunk(struct btrfs_root *root,
3453                            struct btrfs_key *key,
3454                            struct btrfs_chunk *chunk, int item_size)
3455 {
3456         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3457         struct btrfs_disk_key disk_key;
3458         u32 array_size;
3459         u8 *ptr;
3460
3461         array_size = btrfs_super_sys_array_size(super_copy);
3462         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3463                 return -EFBIG;
3464
3465         ptr = super_copy->sys_chunk_array + array_size;
3466         btrfs_cpu_key_to_disk(&disk_key, key);
3467         memcpy(ptr, &disk_key, sizeof(disk_key));
3468         ptr += sizeof(disk_key);
3469         memcpy(ptr, chunk, item_size);
3470         item_size += sizeof(disk_key);
3471         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3472         return 0;
3473 }
3474
3475 /*
3476  * sort the devices in descending order by max_avail, total_avail
3477  */
3478 static int btrfs_cmp_device_info(const void *a, const void *b)
3479 {
3480         const struct btrfs_device_info *di_a = a;
3481         const struct btrfs_device_info *di_b = b;
3482
3483         if (di_a->max_avail > di_b->max_avail)
3484                 return -1;
3485         if (di_a->max_avail < di_b->max_avail)
3486                 return 1;
3487         if (di_a->total_avail > di_b->total_avail)
3488                 return -1;
3489         if (di_a->total_avail < di_b->total_avail)
3490                 return 1;
3491         return 0;
3492 }
3493
3494 struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
3495         { 2, 1, 0, 4, 2, 2 /* raid10 */ },
3496         { 1, 1, 2, 2, 2, 2 /* raid1 */ },
3497         { 1, 2, 1, 1, 1, 2 /* dup */ },
3498         { 1, 1, 0, 2, 1, 1 /* raid0 */ },
3499         { 1, 1, 0, 1, 1, 1 /* single */ },
3500 };
3501
3502 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3503                                struct btrfs_root *extent_root,
3504                                struct map_lookup **map_ret,
3505                                u64 *num_bytes_out, u64 *stripe_size_out,
3506                                u64 start, u64 type)
3507 {
3508         struct btrfs_fs_info *info = extent_root->fs_info;
3509         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3510         struct list_head *cur;
3511         struct map_lookup *map = NULL;
3512         struct extent_map_tree *em_tree;
3513         struct extent_map *em;
3514         struct btrfs_device_info *devices_info = NULL;
3515         u64 total_avail;
3516         int num_stripes;        /* total number of stripes to allocate */
3517         int sub_stripes;        /* sub_stripes info for map */
3518         int dev_stripes;        /* stripes per dev */
3519         int devs_max;           /* max devs to use */
3520         int devs_min;           /* min devs needed */
3521         int devs_increment;     /* ndevs has to be a multiple of this */
3522         int ncopies;            /* how many copies to data has */
3523         int ret;
3524         u64 max_stripe_size;
3525         u64 max_chunk_size;
3526         u64 stripe_size;
3527         u64 num_bytes;
3528         int ndevs;
3529         int i;
3530         int j;
3531         int index;
3532
3533         BUG_ON(!alloc_profile_is_valid(type, 0));
3534
3535         if (list_empty(&fs_devices->alloc_list))
3536                 return -ENOSPC;
3537
3538         index = __get_raid_index(type);
3539
3540         sub_stripes = btrfs_raid_array[index].sub_stripes;
3541         dev_stripes = btrfs_raid_array[index].dev_stripes;
3542         devs_max = btrfs_raid_array[index].devs_max;
3543         devs_min = btrfs_raid_array[index].devs_min;
3544         devs_increment = btrfs_raid_array[index].devs_increment;
3545         ncopies = btrfs_raid_array[index].ncopies;
3546
3547         if (type & BTRFS_BLOCK_GROUP_DATA) {
3548                 max_stripe_size = 1024 * 1024 * 1024;
3549                 max_chunk_size = 10 * max_stripe_size;
3550         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3551                 /* for larger filesystems, use larger metadata chunks */
3552                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3553                         max_stripe_size = 1024 * 1024 * 1024;
3554                 else
3555                         max_stripe_size = 256 * 1024 * 1024;
3556                 max_chunk_size = max_stripe_size;
3557         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3558                 max_stripe_size = 32 * 1024 * 1024;
3559                 max_chunk_size = 2 * max_stripe_size;
3560         } else {
3561                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3562                        type);
3563                 BUG_ON(1);
3564         }
3565
3566         /* we don't want a chunk larger than 10% of writeable space */
3567         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3568                              max_chunk_size);
3569
3570         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3571                                GFP_NOFS);
3572         if (!devices_info)
3573                 return -ENOMEM;
3574
3575         cur = fs_devices->alloc_list.next;
3576
3577         /*
3578          * in the first pass through the devices list, we gather information
3579          * about the available holes on each device.
3580          */
3581         ndevs = 0;
3582         while (cur != &fs_devices->alloc_list) {
3583                 struct btrfs_device *device;
3584                 u64 max_avail;
3585                 u64 dev_offset;
3586
3587                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3588
3589                 cur = cur->next;
3590
3591                 if (!device->writeable) {
3592                         WARN(1, KERN_ERR
3593                                "btrfs: read-only device in alloc_list\n");
3594                         continue;
3595                 }
3596
3597                 if (!device->in_fs_metadata ||
3598                     device->is_tgtdev_for_dev_replace)
3599                         continue;
3600
3601                 if (device->total_bytes > device->bytes_used)
3602                         total_avail = device->total_bytes - device->bytes_used;
3603                 else
3604                         total_avail = 0;
3605
3606                 /* If there is no space on this device, skip it. */
3607                 if (total_avail == 0)
3608                         continue;
3609
3610                 ret = find_free_dev_extent(device,
3611                                            max_stripe_size * dev_stripes,
3612                                            &dev_offset, &max_avail);
3613                 if (ret && ret != -ENOSPC)
3614                         goto error;
3615
3616                 if (ret == 0)
3617                         max_avail = max_stripe_size * dev_stripes;
3618
3619                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3620                         continue;
3621
3622                 devices_info[ndevs].dev_offset = dev_offset;
3623                 devices_info[ndevs].max_avail = max_avail;
3624                 devices_info[ndevs].total_avail = total_avail;
3625                 devices_info[ndevs].dev = device;
3626                 ++ndevs;
3627                 WARN_ON(ndevs > fs_devices->rw_devices);
3628         }
3629
3630         /*
3631          * now sort the devices by hole size / available space
3632          */
3633         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3634              btrfs_cmp_device_info, NULL);
3635
3636         /* round down to number of usable stripes */
3637         ndevs -= ndevs % devs_increment;
3638
3639         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3640                 ret = -ENOSPC;
3641                 goto error;
3642         }
3643
3644         if (devs_max && ndevs > devs_max)
3645                 ndevs = devs_max;
3646         /*
3647          * the primary goal is to maximize the number of stripes, so use as many
3648          * devices as possible, even if the stripes are not maximum sized.
3649          */
3650         stripe_size = devices_info[ndevs-1].max_avail;
3651         num_stripes = ndevs * dev_stripes;
3652
3653         if (stripe_size * ndevs > max_chunk_size * ncopies) {
3654                 stripe_size = max_chunk_size * ncopies;
3655                 do_div(stripe_size, ndevs);
3656         }
3657
3658         do_div(stripe_size, dev_stripes);
3659
3660         /* align to BTRFS_STRIPE_LEN */
3661         do_div(stripe_size, BTRFS_STRIPE_LEN);
3662         stripe_size *= BTRFS_STRIPE_LEN;
3663
3664         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3665         if (!map) {
3666                 ret = -ENOMEM;
3667                 goto error;
3668         }
3669         map->num_stripes = num_stripes;
3670
3671         for (i = 0; i < ndevs; ++i) {
3672                 for (j = 0; j < dev_stripes; ++j) {
3673                         int s = i * dev_stripes + j;
3674                         map->stripes[s].dev = devices_info[i].dev;
3675                         map->stripes[s].physical = devices_info[i].dev_offset +
3676                                                    j * stripe_size;
3677                 }
3678         }
3679         map->sector_size = extent_root->sectorsize;
3680         map->stripe_len = BTRFS_STRIPE_LEN;
3681         map->io_align = BTRFS_STRIPE_LEN;
3682         map->io_width = BTRFS_STRIPE_LEN;
3683         map->type = type;
3684         map->sub_stripes = sub_stripes;
3685
3686         *map_ret = map;
3687         num_bytes = stripe_size * (num_stripes / ncopies);
3688
3689         *stripe_size_out = stripe_size;
3690         *num_bytes_out = num_bytes;
3691
3692         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3693
3694         em = alloc_extent_map();
3695         if (!em) {
3696                 ret = -ENOMEM;
3697                 goto error;
3698         }
3699         em->bdev = (struct block_device *)map;
3700         em->start = start;
3701         em->len = num_bytes;
3702         em->block_start = 0;
3703         em->block_len = em->len;
3704
3705         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3706         write_lock(&em_tree->lock);
3707         ret = add_extent_mapping(em_tree, em);
3708         write_unlock(&em_tree->lock);
3709         free_extent_map(em);
3710         if (ret)
3711                 goto error;
3712
3713         ret = btrfs_make_block_group(trans, extent_root, 0, type,
3714                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3715                                      start, num_bytes);
3716         if (ret)
3717                 goto error;
3718
3719         for (i = 0; i < map->num_stripes; ++i) {
3720                 struct btrfs_device *device;
3721                 u64 dev_offset;
3722
3723                 device = map->stripes[i].dev;
3724                 dev_offset = map->stripes[i].physical;
3725
3726                 ret = btrfs_alloc_dev_extent(trans, device,
3727                                 info->chunk_root->root_key.objectid,
3728                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3729                                 start, dev_offset, stripe_size);
3730                 if (ret) {
3731                         btrfs_abort_transaction(trans, extent_root, ret);
3732                         goto error;
3733                 }
3734         }
3735
3736         kfree(devices_info);
3737         return 0;
3738
3739 error:
3740         kfree(map);
3741         kfree(devices_info);
3742         return ret;
3743 }
3744
3745 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3746                                 struct btrfs_root *extent_root,
3747                                 struct map_lookup *map, u64 chunk_offset,
3748                                 u64 chunk_size, u64 stripe_size)
3749 {
3750         u64 dev_offset;
3751         struct btrfs_key key;
3752         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3753         struct btrfs_device *device;
3754         struct btrfs_chunk *chunk;
3755         struct btrfs_stripe *stripe;
3756         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
3757         int index = 0;
3758         int ret;
3759
3760         chunk = kzalloc(item_size, GFP_NOFS);
3761         if (!chunk)
3762                 return -ENOMEM;
3763
3764         index = 0;
3765         while (index < map->num_stripes) {
3766                 device = map->stripes[index].dev;
3767                 device->bytes_used += stripe_size;
3768                 ret = btrfs_update_device(trans, device);
3769                 if (ret)
3770                         goto out_free;
3771                 index++;
3772         }
3773
3774         spin_lock(&extent_root->fs_info->free_chunk_lock);
3775         extent_root->fs_info->free_chunk_space -= (stripe_size *
3776                                                    map->num_stripes);
3777         spin_unlock(&extent_root->fs_info->free_chunk_lock);
3778
3779         index = 0;
3780         stripe = &chunk->stripe;
3781         while (index < map->num_stripes) {
3782                 device = map->stripes[index].dev;
3783                 dev_offset = map->stripes[index].physical;
3784
3785                 btrfs_set_stack_stripe_devid(stripe, device->devid);
3786                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
3787                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
3788                 stripe++;
3789                 index++;
3790         }
3791
3792         btrfs_set_stack_chunk_length(chunk, chunk_size);
3793         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
3794         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
3795         btrfs_set_stack_chunk_type(chunk, map->type);
3796         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
3797         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
3798         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
3799         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
3800         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
3801
3802         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3803         key.type = BTRFS_CHUNK_ITEM_KEY;
3804         key.offset = chunk_offset;
3805
3806         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
3807
3808         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
3809                 /*
3810                  * TODO: Cleanup of inserted chunk root in case of
3811                  * failure.
3812                  */
3813                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
3814                                              item_size);
3815         }
3816
3817 out_free:
3818         kfree(chunk);
3819         return ret;
3820 }
3821
3822 /*
3823  * Chunk allocation falls into two parts. The first part does works
3824  * that make the new allocated chunk useable, but not do any operation
3825  * that modifies the chunk tree. The second part does the works that
3826  * require modifying the chunk tree. This division is important for the
3827  * bootstrap process of adding storage to a seed btrfs.
3828  */
3829 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3830                       struct btrfs_root *extent_root, u64 type)
3831 {
3832         u64 chunk_offset;
3833         u64 chunk_size;
3834         u64 stripe_size;
3835         struct map_lookup *map;
3836         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3837         int ret;
3838
3839         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3840                               &chunk_offset);
3841         if (ret)
3842                 return ret;
3843
3844         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3845                                   &stripe_size, chunk_offset, type);
3846         if (ret)
3847                 return ret;
3848
3849         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3850                                    chunk_size, stripe_size);
3851         if (ret)
3852                 return ret;
3853         return 0;
3854 }
3855
3856 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
3857                                          struct btrfs_root *root,
3858                                          struct btrfs_device *device)
3859 {
3860         u64 chunk_offset;
3861         u64 sys_chunk_offset;
3862         u64 chunk_size;
3863         u64 sys_chunk_size;
3864         u64 stripe_size;
3865         u64 sys_stripe_size;
3866         u64 alloc_profile;
3867         struct map_lookup *map;
3868         struct map_lookup *sys_map;
3869         struct btrfs_fs_info *fs_info = root->fs_info;
3870         struct btrfs_root *extent_root = fs_info->extent_root;
3871         int ret;
3872
3873         ret = find_next_chunk(fs_info->chunk_root,
3874                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
3875         if (ret)
3876                 return ret;
3877
3878         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
3879                                 fs_info->avail_metadata_alloc_bits;
3880         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3881
3882         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3883                                   &stripe_size, chunk_offset, alloc_profile);
3884         if (ret)
3885                 return ret;
3886
3887         sys_chunk_offset = chunk_offset + chunk_size;
3888
3889         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
3890                                 fs_info->avail_system_alloc_bits;
3891         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3892
3893         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
3894                                   &sys_chunk_size, &sys_stripe_size,
3895                                   sys_chunk_offset, alloc_profile);
3896         if (ret) {
3897                 btrfs_abort_transaction(trans, root, ret);
3898                 goto out;
3899         }
3900
3901         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
3902         if (ret) {
3903                 btrfs_abort_transaction(trans, root, ret);
3904                 goto out;
3905         }
3906
3907         /*
3908          * Modifying chunk tree needs allocating new blocks from both
3909          * system block group and metadata block group. So we only can
3910          * do operations require modifying the chunk tree after both
3911          * block groups were created.
3912          */
3913         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3914                                    chunk_size, stripe_size);
3915         if (ret) {
3916                 btrfs_abort_transaction(trans, root, ret);
3917                 goto out;
3918         }
3919
3920         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
3921                                    sys_chunk_offset, sys_chunk_size,
3922                                    sys_stripe_size);
3923         if (ret)
3924                 btrfs_abort_transaction(trans, root, ret);
3925
3926 out:
3927
3928         return ret;
3929 }
3930
3931 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
3932 {
3933         struct extent_map *em;
3934         struct map_lookup *map;
3935         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3936         int readonly = 0;
3937         int i;
3938
3939         read_lock(&map_tree->map_tree.lock);
3940         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3941         read_unlock(&map_tree->map_tree.lock);
3942         if (!em)
3943                 return 1;
3944
3945         if (btrfs_test_opt(root, DEGRADED)) {
3946                 free_extent_map(em);
3947                 return 0;
3948         }
3949
3950         map = (struct map_lookup *)em->bdev;
3951         for (i = 0; i < map->num_stripes; i++) {
3952                 if (!map->stripes[i].dev->writeable) {
3953                         readonly = 1;
3954                         break;
3955                 }
3956         }
3957         free_extent_map(em);
3958         return readonly;
3959 }
3960
3961 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
3962 {
3963         extent_map_tree_init(&tree->map_tree);
3964 }
3965
3966 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
3967 {
3968         struct extent_map *em;
3969
3970         while (1) {
3971                 write_lock(&tree->map_tree.lock);
3972                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
3973                 if (em)
3974                         remove_extent_mapping(&tree->map_tree, em);
3975                 write_unlock(&tree->map_tree.lock);
3976                 if (!em)
3977                         break;
3978                 kfree(em->bdev);
3979                 /* once for us */
3980                 free_extent_map(em);
3981                 /* once for the tree */
3982                 free_extent_map(em);
3983         }
3984 }
3985
3986 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
3987 {
3988         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
3989         struct extent_map *em;
3990         struct map_lookup *map;
3991         struct extent_map_tree *em_tree = &map_tree->map_tree;
3992         int ret;
3993
3994         read_lock(&em_tree->lock);
3995         em = lookup_extent_mapping(em_tree, logical, len);
3996         read_unlock(&em_tree->lock);
3997         BUG_ON(!em);
3998
3999         BUG_ON(em->start > logical || em->start + em->len < logical);
4000         map = (struct map_lookup *)em->bdev;
4001         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
4002                 ret = map->num_stripes;
4003         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4004                 ret = map->sub_stripes;
4005         else
4006                 ret = 1;
4007         free_extent_map(em);
4008
4009         btrfs_dev_replace_lock(&fs_info->dev_replace);
4010         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
4011                 ret++;
4012         btrfs_dev_replace_unlock(&fs_info->dev_replace);
4013
4014         return ret;
4015 }
4016
4017 static int find_live_mirror(struct btrfs_fs_info *fs_info,
4018                             struct map_lookup *map, int first, int num,
4019                             int optimal, int dev_replace_is_ongoing)
4020 {
4021         int i;
4022         int tolerance;
4023         struct btrfs_device *srcdev;
4024
4025         if (dev_replace_is_ongoing &&
4026             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
4027              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
4028                 srcdev = fs_info->dev_replace.srcdev;
4029         else
4030                 srcdev = NULL;
4031
4032         /*
4033          * try to avoid the drive that is the source drive for a
4034          * dev-replace procedure, only choose it if no other non-missing
4035          * mirror is available
4036          */
4037         for (tolerance = 0; tolerance < 2; tolerance++) {
4038                 if (map->stripes[optimal].dev->bdev &&
4039                     (tolerance || map->stripes[optimal].dev != srcdev))
4040                         return optimal;
4041                 for (i = first; i < first + num; i++) {
4042                         if (map->stripes[i].dev->bdev &&
4043                             (tolerance || map->stripes[i].dev != srcdev))
4044                                 return i;
4045                 }
4046         }
4047
4048         /* we couldn't find one that doesn't fail.  Just return something
4049          * and the io error handling code will clean up eventually
4050          */
4051         return optimal;
4052 }
4053
4054 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4055                              u64 logical, u64 *length,
4056                              struct btrfs_bio **bbio_ret,
4057                              int mirror_num)
4058 {
4059         struct extent_map *em;
4060         struct map_lookup *map;
4061         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4062         struct extent_map_tree *em_tree = &map_tree->map_tree;
4063         u64 offset;
4064         u64 stripe_offset;
4065         u64 stripe_end_offset;
4066         u64 stripe_nr;
4067         u64 stripe_nr_orig;
4068         u64 stripe_nr_end;
4069         int stripe_index;
4070         int i;
4071         int ret = 0;
4072         int num_stripes;
4073         int max_errors = 0;
4074         struct btrfs_bio *bbio = NULL;
4075         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
4076         int dev_replace_is_ongoing = 0;
4077         int num_alloc_stripes;
4078         int patch_the_first_stripe_for_dev_replace = 0;
4079         u64 physical_to_patch_in_first_stripe = 0;
4080
4081         read_lock(&em_tree->lock);
4082         em = lookup_extent_mapping(em_tree, logical, *length);
4083         read_unlock(&em_tree->lock);
4084
4085         if (!em) {
4086                 printk(KERN_CRIT "btrfs: unable to find logical %llu len %llu\n",
4087                        (unsigned long long)logical,
4088                        (unsigned long long)*length);
4089                 BUG();
4090         }
4091
4092         BUG_ON(em->start > logical || em->start + em->len < logical);
4093         map = (struct map_lookup *)em->bdev;
4094         offset = logical - em->start;
4095
4096         stripe_nr = offset;
4097         /*
4098          * stripe_nr counts the total number of stripes we have to stride
4099          * to get to this block
4100          */
4101         do_div(stripe_nr, map->stripe_len);
4102
4103         stripe_offset = stripe_nr * map->stripe_len;
4104         BUG_ON(offset < stripe_offset);
4105
4106         /* stripe_offset is the offset of this block in its stripe*/
4107         stripe_offset = offset - stripe_offset;
4108
4109         if (rw & REQ_DISCARD)
4110                 *length = min_t(u64, em->len - offset, *length);
4111         else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
4112                 /* we limit the length of each bio to what fits in a stripe */
4113                 *length = min_t(u64, em->len - offset,
4114                                 map->stripe_len - stripe_offset);
4115         } else {
4116                 *length = em->len - offset;
4117         }
4118
4119         if (!bbio_ret)
4120                 goto out;
4121
4122         btrfs_dev_replace_lock(dev_replace);
4123         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
4124         if (!dev_replace_is_ongoing)
4125                 btrfs_dev_replace_unlock(dev_replace);
4126
4127         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
4128             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
4129             dev_replace->tgtdev != NULL) {
4130                 /*
4131                  * in dev-replace case, for repair case (that's the only
4132                  * case where the mirror is selected explicitly when
4133                  * calling btrfs_map_block), blocks left of the left cursor
4134                  * can also be read from the target drive.
4135                  * For REQ_GET_READ_MIRRORS, the target drive is added as
4136                  * the last one to the array of stripes. For READ, it also
4137                  * needs to be supported using the same mirror number.
4138                  * If the requested block is not left of the left cursor,
4139                  * EIO is returned. This can happen because btrfs_num_copies()
4140                  * returns one more in the dev-replace case.
4141                  */
4142                 u64 tmp_length = *length;
4143                 struct btrfs_bio *tmp_bbio = NULL;
4144                 int tmp_num_stripes;
4145                 u64 srcdev_devid = dev_replace->srcdev->devid;
4146                 int index_srcdev = 0;
4147                 int found = 0;
4148                 u64 physical_of_found = 0;
4149
4150                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
4151                              logical, &tmp_length, &tmp_bbio, 0);
4152                 if (ret) {
4153                         WARN_ON(tmp_bbio != NULL);
4154                         goto out;
4155                 }
4156
4157                 tmp_num_stripes = tmp_bbio->num_stripes;
4158                 if (mirror_num > tmp_num_stripes) {
4159                         /*
4160                          * REQ_GET_READ_MIRRORS does not contain this
4161                          * mirror, that means that the requested area
4162                          * is not left of the left cursor
4163                          */
4164                         ret = -EIO;
4165                         kfree(tmp_bbio);
4166                         goto out;
4167                 }
4168
4169                 /*
4170                  * process the rest of the function using the mirror_num
4171                  * of the source drive. Therefore look it up first.
4172                  * At the end, patch the device pointer to the one of the
4173                  * target drive.
4174                  */
4175                 for (i = 0; i < tmp_num_stripes; i++) {
4176                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
4177                                 /*
4178                                  * In case of DUP, in order to keep it
4179                                  * simple, only add the mirror with the
4180                                  * lowest physical address
4181                                  */
4182                                 if (found &&
4183                                     physical_of_found <=
4184                                      tmp_bbio->stripes[i].physical)
4185                                         continue;
4186                                 index_srcdev = i;
4187                                 found = 1;
4188                                 physical_of_found =
4189                                         tmp_bbio->stripes[i].physical;
4190                         }
4191                 }
4192
4193                 if (found) {
4194                         mirror_num = index_srcdev + 1;
4195                         patch_the_first_stripe_for_dev_replace = 1;
4196                         physical_to_patch_in_first_stripe = physical_of_found;
4197                 } else {
4198                         WARN_ON(1);
4199                         ret = -EIO;
4200                         kfree(tmp_bbio);
4201                         goto out;
4202                 }
4203
4204                 kfree(tmp_bbio);
4205         } else if (mirror_num > map->num_stripes) {
4206                 mirror_num = 0;
4207         }
4208
4209         num_stripes = 1;
4210         stripe_index = 0;
4211         stripe_nr_orig = stripe_nr;
4212         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
4213                         (~(map->stripe_len - 1));
4214         do_div(stripe_nr_end, map->stripe_len);
4215         stripe_end_offset = stripe_nr_end * map->stripe_len -
4216                             (offset + *length);
4217         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4218                 if (rw & REQ_DISCARD)
4219                         num_stripes = min_t(u64, map->num_stripes,
4220                                             stripe_nr_end - stripe_nr_orig);
4221                 stripe_index = do_div(stripe_nr, map->num_stripes);
4222         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
4223                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
4224                         num_stripes = map->num_stripes;
4225                 else if (mirror_num)
4226                         stripe_index = mirror_num - 1;
4227                 else {
4228                         stripe_index = find_live_mirror(fs_info, map, 0,
4229                                             map->num_stripes,
4230                                             current->pid % map->num_stripes,
4231                                             dev_replace_is_ongoing);
4232                         mirror_num = stripe_index + 1;
4233                 }
4234
4235         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
4236                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
4237                         num_stripes = map->num_stripes;
4238                 } else if (mirror_num) {
4239                         stripe_index = mirror_num - 1;
4240                 } else {
4241                         mirror_num = 1;
4242                 }
4243
4244         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4245                 int factor = map->num_stripes / map->sub_stripes;
4246
4247                 stripe_index = do_div(stripe_nr, factor);
4248                 stripe_index *= map->sub_stripes;
4249
4250                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
4251                         num_stripes = map->sub_stripes;
4252                 else if (rw & REQ_DISCARD)
4253                         num_stripes = min_t(u64, map->sub_stripes *
4254                                             (stripe_nr_end - stripe_nr_orig),
4255                                             map->num_stripes);
4256                 else if (mirror_num)
4257                         stripe_index += mirror_num - 1;
4258                 else {
4259                         int old_stripe_index = stripe_index;
4260                         stripe_index = find_live_mirror(fs_info, map,
4261                                               stripe_index,
4262                                               map->sub_stripes, stripe_index +
4263                                               current->pid % map->sub_stripes,
4264                                               dev_replace_is_ongoing);
4265                         mirror_num = stripe_index - old_stripe_index + 1;
4266                 }
4267         } else {
4268                 /*
4269                  * after this do_div call, stripe_nr is the number of stripes
4270                  * on this device we have to walk to find the data, and
4271                  * stripe_index is the number of our device in the stripe array
4272                  */
4273                 stripe_index = do_div(stripe_nr, map->num_stripes);
4274                 mirror_num = stripe_index + 1;
4275         }
4276         BUG_ON(stripe_index >= map->num_stripes);
4277
4278         num_alloc_stripes = num_stripes;
4279         if (dev_replace_is_ongoing) {
4280                 if (rw & (REQ_WRITE | REQ_DISCARD))
4281                         num_alloc_stripes <<= 1;
4282                 if (rw & REQ_GET_READ_MIRRORS)
4283                         num_alloc_stripes++;
4284         }
4285         bbio = kzalloc(btrfs_bio_size(num_alloc_stripes), GFP_NOFS);
4286         if (!bbio) {
4287                 ret = -ENOMEM;
4288                 goto out;
4289         }
4290         atomic_set(&bbio->error, 0);
4291
4292         if (rw & REQ_DISCARD) {
4293                 int factor = 0;
4294                 int sub_stripes = 0;
4295                 u64 stripes_per_dev = 0;
4296                 u32 remaining_stripes = 0;
4297                 u32 last_stripe = 0;
4298
4299                 if (map->type &
4300                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
4301                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4302                                 sub_stripes = 1;
4303                         else
4304                                 sub_stripes = map->sub_stripes;
4305
4306                         factor = map->num_stripes / sub_stripes;
4307                         stripes_per_dev = div_u64_rem(stripe_nr_end -
4308                                                       stripe_nr_orig,
4309                                                       factor,
4310                                                       &remaining_stripes);
4311                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
4312                         last_stripe *= sub_stripes;
4313                 }
4314
4315                 for (i = 0; i < num_stripes; i++) {
4316                         bbio->stripes[i].physical =
4317                                 map->stripes[stripe_index].physical +
4318                                 stripe_offset + stripe_nr * map->stripe_len;
4319                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
4320
4321                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
4322                                          BTRFS_BLOCK_GROUP_RAID10)) {
4323                                 bbio->stripes[i].length = stripes_per_dev *
4324                                                           map->stripe_len;
4325
4326                                 if (i / sub_stripes < remaining_stripes)
4327                                         bbio->stripes[i].length +=
4328                                                 map->stripe_len;
4329
4330                                 /*
4331                                  * Special for the first stripe and
4332                                  * the last stripe:
4333                                  *
4334                                  * |-------|...|-------|
4335                                  *     |----------|
4336                                  *    off     end_off
4337                                  */
4338                                 if (i < sub_stripes)
4339                                         bbio->stripes[i].length -=
4340                                                 stripe_offset;
4341
4342                                 if (stripe_index >= last_stripe &&
4343                                     stripe_index <= (last_stripe +
4344                                                      sub_stripes - 1))
4345                                         bbio->stripes[i].length -=
4346                                                 stripe_end_offset;
4347
4348                                 if (i == sub_stripes - 1)
4349                                         stripe_offset = 0;
4350                         } else
4351                                 bbio->stripes[i].length = *length;
4352
4353                         stripe_index++;
4354                         if (stripe_index == map->num_stripes) {
4355                                 /* This could only happen for RAID0/10 */
4356                                 stripe_index = 0;
4357                                 stripe_nr++;
4358                         }
4359                 }
4360         } else {
4361                 for (i = 0; i < num_stripes; i++) {
4362                         bbio->stripes[i].physical =
4363                                 map->stripes[stripe_index].physical +
4364                                 stripe_offset +
4365                                 stripe_nr * map->stripe_len;
4366                         bbio->stripes[i].dev =
4367                                 map->stripes[stripe_index].dev;
4368                         stripe_index++;
4369                 }
4370         }
4371
4372         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) {
4373                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4374                                  BTRFS_BLOCK_GROUP_RAID10 |
4375                                  BTRFS_BLOCK_GROUP_DUP)) {
4376                         max_errors = 1;
4377                 }
4378         }
4379
4380         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
4381             dev_replace->tgtdev != NULL) {
4382                 int index_where_to_add;
4383                 u64 srcdev_devid = dev_replace->srcdev->devid;
4384
4385                 /*
4386                  * duplicate the write operations while the dev replace
4387                  * procedure is running. Since the copying of the old disk
4388                  * to the new disk takes place at run time while the
4389                  * filesystem is mounted writable, the regular write
4390                  * operations to the old disk have to be duplicated to go
4391                  * to the new disk as well.
4392                  * Note that device->missing is handled by the caller, and
4393                  * that the write to the old disk is already set up in the
4394                  * stripes array.
4395                  */
4396                 index_where_to_add = num_stripes;
4397                 for (i = 0; i < num_stripes; i++) {
4398                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4399                                 /* write to new disk, too */
4400                                 struct btrfs_bio_stripe *new =
4401                                         bbio->stripes + index_where_to_add;
4402                                 struct btrfs_bio_stripe *old =
4403                                         bbio->stripes + i;
4404
4405                                 new->physical = old->physical;
4406                                 new->length = old->length;
4407                                 new->dev = dev_replace->tgtdev;
4408                                 index_where_to_add++;
4409                                 max_errors++;
4410                         }
4411                 }
4412                 num_stripes = index_where_to_add;
4413         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
4414                    dev_replace->tgtdev != NULL) {
4415                 u64 srcdev_devid = dev_replace->srcdev->devid;
4416                 int index_srcdev = 0;
4417                 int found = 0;
4418                 u64 physical_of_found = 0;
4419
4420                 /*
4421                  * During the dev-replace procedure, the target drive can
4422                  * also be used to read data in case it is needed to repair
4423                  * a corrupt block elsewhere. This is possible if the
4424                  * requested area is left of the left cursor. In this area,
4425                  * the target drive is a full copy of the source drive.
4426                  */
4427                 for (i = 0; i < num_stripes; i++) {
4428                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4429                                 /*
4430                                  * In case of DUP, in order to keep it
4431                                  * simple, only add the mirror with the
4432                                  * lowest physical address
4433                                  */
4434                                 if (found &&
4435                                     physical_of_found <=
4436                                      bbio->stripes[i].physical)
4437                                         continue;
4438                                 index_srcdev = i;
4439                                 found = 1;
4440                                 physical_of_found = bbio->stripes[i].physical;
4441                         }
4442                 }
4443                 if (found) {
4444                         u64 length = map->stripe_len;
4445
4446                         if (physical_of_found + length <=
4447                             dev_replace->cursor_left) {
4448                                 struct btrfs_bio_stripe *tgtdev_stripe =
4449                                         bbio->stripes + num_stripes;
4450
4451                                 tgtdev_stripe->physical = physical_of_found;
4452                                 tgtdev_stripe->length =
4453                                         bbio->stripes[index_srcdev].length;
4454                                 tgtdev_stripe->dev = dev_replace->tgtdev;
4455
4456                                 num_stripes++;
4457                         }
4458                 }
4459         }
4460
4461         *bbio_ret = bbio;
4462         bbio->num_stripes = num_stripes;
4463         bbio->max_errors = max_errors;
4464         bbio->mirror_num = mirror_num;
4465
4466         /*
4467          * this is the case that REQ_READ && dev_replace_is_ongoing &&
4468          * mirror_num == num_stripes + 1 && dev_replace target drive is
4469          * available as a mirror
4470          */
4471         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
4472                 WARN_ON(num_stripes > 1);
4473                 bbio->stripes[0].dev = dev_replace->tgtdev;
4474                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
4475                 bbio->mirror_num = map->num_stripes + 1;
4476         }
4477 out:
4478         if (dev_replace_is_ongoing)
4479                 btrfs_dev_replace_unlock(dev_replace);
4480         free_extent_map(em);
4481         return ret;
4482 }
4483
4484 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4485                       u64 logical, u64 *length,
4486                       struct btrfs_bio **bbio_ret, int mirror_num)
4487 {
4488         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
4489                                  mirror_num);
4490 }
4491
4492 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4493                      u64 chunk_start, u64 physical, u64 devid,
4494                      u64 **logical, int *naddrs, int *stripe_len)
4495 {
4496         struct extent_map_tree *em_tree = &map_tree->map_tree;
4497         struct extent_map *em;
4498         struct map_lookup *map;
4499         u64 *buf;
4500         u64 bytenr;
4501         u64 length;
4502         u64 stripe_nr;
4503         int i, j, nr = 0;
4504
4505         read_lock(&em_tree->lock);
4506         em = lookup_extent_mapping(em_tree, chunk_start, 1);
4507         read_unlock(&em_tree->lock);
4508
4509         BUG_ON(!em || em->start != chunk_start);
4510         map = (struct map_lookup *)em->bdev;
4511
4512         length = em->len;
4513         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4514                 do_div(length, map->num_stripes / map->sub_stripes);
4515         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4516                 do_div(length, map->num_stripes);
4517
4518         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4519         BUG_ON(!buf); /* -ENOMEM */
4520
4521         for (i = 0; i < map->num_stripes; i++) {
4522                 if (devid && map->stripes[i].dev->devid != devid)
4523                         continue;
4524                 if (map->stripes[i].physical > physical ||
4525                     map->stripes[i].physical + length <= physical)
4526                         continue;
4527
4528                 stripe_nr = physical - map->stripes[i].physical;
4529                 do_div(stripe_nr, map->stripe_len);
4530
4531                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4532                         stripe_nr = stripe_nr * map->num_stripes + i;
4533                         do_div(stripe_nr, map->sub_stripes);
4534                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4535                         stripe_nr = stripe_nr * map->num_stripes + i;
4536                 }
4537                 bytenr = chunk_start + stripe_nr * map->stripe_len;
4538                 WARN_ON(nr >= map->num_stripes);
4539                 for (j = 0; j < nr; j++) {
4540                         if (buf[j] == bytenr)
4541                                 break;
4542                 }
4543                 if (j == nr) {
4544                         WARN_ON(nr >= map->num_stripes);
4545                         buf[nr++] = bytenr;
4546                 }
4547         }
4548
4549         *logical = buf;
4550         *naddrs = nr;
4551         *stripe_len = map->stripe_len;
4552
4553         free_extent_map(em);
4554         return 0;
4555 }
4556
4557 static void *merge_stripe_index_into_bio_private(void *bi_private,
4558                                                  unsigned int stripe_index)
4559 {
4560         /*
4561          * with single, dup, RAID0, RAID1 and RAID10, stripe_index is
4562          * at most 1.
4563          * The alternative solution (instead of stealing bits from the
4564          * pointer) would be to allocate an intermediate structure
4565          * that contains the old private pointer plus the stripe_index.
4566          */
4567         BUG_ON((((uintptr_t)bi_private) & 3) != 0);
4568         BUG_ON(stripe_index > 3);
4569         return (void *)(((uintptr_t)bi_private) | stripe_index);
4570 }
4571
4572 static struct btrfs_bio *extract_bbio_from_bio_private(void *bi_private)
4573 {
4574         return (struct btrfs_bio *)(((uintptr_t)bi_private) & ~((uintptr_t)3));
4575 }
4576
4577 static unsigned int extract_stripe_index_from_bio_private(void *bi_private)
4578 {
4579         return (unsigned int)((uintptr_t)bi_private) & 3;
4580 }
4581
4582 static void btrfs_end_bio(struct bio *bio, int err)
4583 {
4584         struct btrfs_bio *bbio = extract_bbio_from_bio_private(bio->bi_private);
4585         int is_orig_bio = 0;
4586
4587         if (err) {
4588                 atomic_inc(&bbio->error);
4589                 if (err == -EIO || err == -EREMOTEIO) {
4590                         unsigned int stripe_index =
4591                                 extract_stripe_index_from_bio_private(
4592                                         bio->bi_private);
4593                         struct btrfs_device *dev;
4594
4595                         BUG_ON(stripe_index >= bbio->num_stripes);
4596                         dev = bbio->stripes[stripe_index].dev;
4597                         if (dev->bdev) {
4598                                 if (bio->bi_rw & WRITE)
4599                                         btrfs_dev_stat_inc(dev,
4600                                                 BTRFS_DEV_STAT_WRITE_ERRS);
4601                                 else
4602                                         btrfs_dev_stat_inc(dev,
4603                                                 BTRFS_DEV_STAT_READ_ERRS);
4604                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
4605                                         btrfs_dev_stat_inc(dev,
4606                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
4607                                 btrfs_dev_stat_print_on_error(dev);
4608                         }
4609                 }
4610         }
4611
4612         if (bio == bbio->orig_bio)
4613                 is_orig_bio = 1;
4614
4615         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4616                 if (!is_orig_bio) {
4617                         bio_put(bio);
4618                         bio = bbio->orig_bio;
4619                 }
4620                 bio->bi_private = bbio->private;
4621                 bio->bi_end_io = bbio->end_io;
4622                 bio->bi_bdev = (struct block_device *)
4623                                         (unsigned long)bbio->mirror_num;
4624                 /* only send an error to the higher layers if it is
4625                  * beyond the tolerance of the multi-bio
4626                  */
4627                 if (atomic_read(&bbio->error) > bbio->max_errors) {
4628                         err = -EIO;
4629                 } else {
4630                         /*
4631                          * this bio is actually up to date, we didn't
4632                          * go over the max number of errors
4633                          */
4634                         set_bit(BIO_UPTODATE, &bio->bi_flags);
4635                         err = 0;
4636                 }
4637                 kfree(bbio);
4638
4639                 bio_endio(bio, err);
4640         } else if (!is_orig_bio) {
4641                 bio_put(bio);
4642         }
4643 }
4644
4645 struct async_sched {
4646         struct bio *bio;
4647         int rw;
4648         struct btrfs_fs_info *info;
4649         struct btrfs_work work;
4650 };
4651
4652 /*
4653  * see run_scheduled_bios for a description of why bios are collected for
4654  * async submit.
4655  *
4656  * This will add one bio to the pending list for a device and make sure
4657  * the work struct is scheduled.
4658  */
4659 static noinline void schedule_bio(struct btrfs_root *root,
4660                                  struct btrfs_device *device,
4661                                  int rw, struct bio *bio)
4662 {
4663         int should_queue = 1;
4664         struct btrfs_pending_bios *pending_bios;
4665
4666         /* don't bother with additional async steps for reads, right now */
4667         if (!(rw & REQ_WRITE)) {
4668                 bio_get(bio);
4669                 btrfsic_submit_bio(rw, bio);
4670                 bio_put(bio);
4671                 return;
4672         }
4673
4674         /*
4675          * nr_async_bios allows us to reliably return congestion to the
4676          * higher layers.  Otherwise, the async bio makes it appear we have
4677          * made progress against dirty pages when we've really just put it
4678          * on a queue for later
4679          */
4680         atomic_inc(&root->fs_info->nr_async_bios);
4681         WARN_ON(bio->bi_next);
4682         bio->bi_next = NULL;
4683         bio->bi_rw |= rw;
4684
4685         spin_lock(&device->io_lock);
4686         if (bio->bi_rw & REQ_SYNC)
4687                 pending_bios = &device->pending_sync_bios;
4688         else
4689                 pending_bios = &device->pending_bios;
4690
4691         if (pending_bios->tail)
4692                 pending_bios->tail->bi_next = bio;
4693
4694         pending_bios->tail = bio;
4695         if (!pending_bios->head)
4696                 pending_bios->head = bio;
4697         if (device->running_pending)
4698                 should_queue = 0;
4699
4700         spin_unlock(&device->io_lock);
4701
4702         if (should_queue)
4703                 btrfs_queue_worker(&root->fs_info->submit_workers,
4704                                    &device->work);
4705 }
4706
4707 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
4708                        sector_t sector)
4709 {
4710         struct bio_vec *prev;
4711         struct request_queue *q = bdev_get_queue(bdev);
4712         unsigned short max_sectors = queue_max_sectors(q);
4713         struct bvec_merge_data bvm = {
4714                 .bi_bdev = bdev,
4715                 .bi_sector = sector,
4716                 .bi_rw = bio->bi_rw,
4717         };
4718
4719         if (bio->bi_vcnt == 0) {
4720                 WARN_ON(1);
4721                 return 1;
4722         }
4723
4724         prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
4725         if ((bio->bi_size >> 9) > max_sectors)
4726                 return 0;
4727
4728         if (!q->merge_bvec_fn)
4729                 return 1;
4730
4731         bvm.bi_size = bio->bi_size - prev->bv_len;
4732         if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
4733                 return 0;
4734         return 1;
4735 }
4736
4737 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4738                               struct bio *bio, u64 physical, int dev_nr,
4739                               int rw, int async)
4740 {
4741         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
4742
4743         bio->bi_private = bbio;
4744         bio->bi_private = merge_stripe_index_into_bio_private(
4745                         bio->bi_private, (unsigned int)dev_nr);
4746         bio->bi_end_io = btrfs_end_bio;
4747         bio->bi_sector = physical >> 9;
4748 #ifdef DEBUG
4749         {
4750                 struct rcu_string *name;
4751
4752                 rcu_read_lock();
4753                 name = rcu_dereference(dev->name);
4754                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
4755                          "(%s id %llu), size=%u\n", rw,
4756                          (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
4757                          name->str, dev->devid, bio->bi_size);
4758                 rcu_read_unlock();
4759         }
4760 #endif
4761         bio->bi_bdev = dev->bdev;
4762         if (async)
4763                 schedule_bio(root, dev, rw, bio);
4764         else
4765                 btrfsic_submit_bio(rw, bio);
4766 }
4767
4768 static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4769                               struct bio *first_bio, struct btrfs_device *dev,
4770                               int dev_nr, int rw, int async)
4771 {
4772         struct bio_vec *bvec = first_bio->bi_io_vec;
4773         struct bio *bio;
4774         int nr_vecs = bio_get_nr_vecs(dev->bdev);
4775         u64 physical = bbio->stripes[dev_nr].physical;
4776
4777 again:
4778         bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
4779         if (!bio)
4780                 return -ENOMEM;
4781
4782         while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
4783                 if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
4784                                  bvec->bv_offset) < bvec->bv_len) {
4785                         u64 len = bio->bi_size;
4786
4787                         atomic_inc(&bbio->stripes_pending);
4788                         submit_stripe_bio(root, bbio, bio, physical, dev_nr,
4789                                           rw, async);
4790                         physical += len;
4791                         goto again;
4792                 }
4793                 bvec++;
4794         }
4795
4796         submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
4797         return 0;
4798 }
4799
4800 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
4801 {
4802         atomic_inc(&bbio->error);
4803         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4804                 bio->bi_private = bbio->private;
4805                 bio->bi_end_io = bbio->end_io;
4806                 bio->bi_bdev = (struct block_device *)
4807                         (unsigned long)bbio->mirror_num;
4808                 bio->bi_sector = logical >> 9;
4809                 kfree(bbio);
4810                 bio_endio(bio, -EIO);
4811         }
4812 }
4813
4814 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
4815                   int mirror_num, int async_submit)
4816 {
4817         struct btrfs_device *dev;
4818         struct bio *first_bio = bio;
4819         u64 logical = (u64)bio->bi_sector << 9;
4820         u64 length = 0;
4821         u64 map_length;
4822         int ret;
4823         int dev_nr = 0;
4824         int total_devs = 1;
4825         struct btrfs_bio *bbio = NULL;
4826
4827         length = bio->bi_size;
4828         map_length = length;
4829
4830         ret = btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
4831                               mirror_num);
4832         if (ret)
4833                 return ret;
4834
4835         total_devs = bbio->num_stripes;
4836         if (map_length < length) {
4837                 printk(KERN_CRIT "btrfs: mapping failed logical %llu bio len %llu "
4838                        "len %llu\n", (unsigned long long)logical,
4839                        (unsigned long long)length,
4840                        (unsigned long long)map_length);
4841                 BUG();
4842         }
4843
4844         bbio->orig_bio = first_bio;
4845         bbio->private = first_bio->bi_private;
4846         bbio->end_io = first_bio->bi_end_io;
4847         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
4848
4849         while (dev_nr < total_devs) {
4850                 dev = bbio->stripes[dev_nr].dev;
4851                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
4852                         bbio_error(bbio, first_bio, logical);
4853                         dev_nr++;
4854                         continue;
4855                 }
4856
4857                 /*
4858                  * Check and see if we're ok with this bio based on it's size
4859                  * and offset with the given device.
4860                  */
4861                 if (!bio_size_ok(dev->bdev, first_bio,
4862                                  bbio->stripes[dev_nr].physical >> 9)) {
4863                         ret = breakup_stripe_bio(root, bbio, first_bio, dev,
4864                                                  dev_nr, rw, async_submit);
4865                         BUG_ON(ret);
4866                         dev_nr++;
4867                         continue;
4868                 }
4869
4870                 if (dev_nr < total_devs - 1) {
4871                         bio = bio_clone(first_bio, GFP_NOFS);
4872                         BUG_ON(!bio); /* -ENOMEM */
4873                 } else {
4874                         bio = first_bio;
4875                 }
4876
4877                 submit_stripe_bio(root, bbio, bio,
4878                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
4879                                   async_submit);
4880                 dev_nr++;
4881         }
4882         return 0;
4883 }
4884
4885 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
4886                                        u8 *uuid, u8 *fsid)
4887 {
4888         struct btrfs_device *device;
4889         struct btrfs_fs_devices *cur_devices;
4890
4891         cur_devices = fs_info->fs_devices;
4892         while (cur_devices) {
4893                 if (!fsid ||
4894                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4895                         device = __find_device(&cur_devices->devices,
4896                                                devid, uuid);
4897                         if (device)
4898                                 return device;
4899                 }
4900                 cur_devices = cur_devices->seed;
4901         }
4902         return NULL;
4903 }
4904
4905 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
4906                                             u64 devid, u8 *dev_uuid)
4907 {
4908         struct btrfs_device *device;
4909         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4910
4911         device = kzalloc(sizeof(*device), GFP_NOFS);
4912         if (!device)
4913                 return NULL;
4914         list_add(&device->dev_list,
4915                  &fs_devices->devices);
4916         device->dev_root = root->fs_info->dev_root;
4917         device->devid = devid;
4918         device->work.func = pending_bios_fn;
4919         device->fs_devices = fs_devices;
4920         device->missing = 1;
4921         fs_devices->num_devices++;
4922         fs_devices->missing_devices++;
4923         spin_lock_init(&device->io_lock);
4924         INIT_LIST_HEAD(&device->dev_alloc_list);
4925         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
4926         return device;
4927 }
4928
4929 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
4930                           struct extent_buffer *leaf,
4931                           struct btrfs_chunk *chunk)
4932 {
4933         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4934         struct map_lookup *map;
4935         struct extent_map *em;
4936         u64 logical;
4937         u64 length;
4938         u64 devid;
4939         u8 uuid[BTRFS_UUID_SIZE];
4940         int num_stripes;
4941         int ret;
4942         int i;
4943
4944         logical = key->offset;
4945         length = btrfs_chunk_length(leaf, chunk);
4946
4947         read_lock(&map_tree->map_tree.lock);
4948         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
4949         read_unlock(&map_tree->map_tree.lock);
4950
4951         /* already mapped? */
4952         if (em && em->start <= logical && em->start + em->len > logical) {
4953                 free_extent_map(em);
4954                 return 0;
4955         } else if (em) {
4956                 free_extent_map(em);
4957         }
4958
4959         em = alloc_extent_map();
4960         if (!em)
4961                 return -ENOMEM;
4962         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
4963         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4964         if (!map) {
4965                 free_extent_map(em);
4966                 return -ENOMEM;
4967         }
4968
4969         em->bdev = (struct block_device *)map;
4970         em->start = logical;
4971         em->len = length;
4972         em->orig_start = 0;
4973         em->block_start = 0;
4974         em->block_len = em->len;
4975
4976         map->num_stripes = num_stripes;
4977         map->io_width = btrfs_chunk_io_width(leaf, chunk);
4978         map->io_align = btrfs_chunk_io_align(leaf, chunk);
4979         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
4980         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
4981         map->type = btrfs_chunk_type(leaf, chunk);
4982         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
4983         for (i = 0; i < num_stripes; i++) {
4984                 map->stripes[i].physical =
4985                         btrfs_stripe_offset_nr(leaf, chunk, i);
4986                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
4987                 read_extent_buffer(leaf, uuid, (unsigned long)
4988                                    btrfs_stripe_dev_uuid_nr(chunk, i),
4989                                    BTRFS_UUID_SIZE);
4990                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
4991                                                         uuid, NULL);
4992                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
4993                         kfree(map);
4994                         free_extent_map(em);
4995                         return -EIO;
4996                 }
4997                 if (!map->stripes[i].dev) {
4998                         map->stripes[i].dev =
4999                                 add_missing_dev(root, devid, uuid);
5000                         if (!map->stripes[i].dev) {
5001                                 kfree(map);
5002                                 free_extent_map(em);
5003                                 return -EIO;
5004                         }
5005                 }
5006                 map->stripes[i].dev->in_fs_metadata = 1;
5007         }
5008
5009         write_lock(&map_tree->map_tree.lock);
5010         ret = add_extent_mapping(&map_tree->map_tree, em);
5011         write_unlock(&map_tree->map_tree.lock);
5012         BUG_ON(ret); /* Tree corruption */
5013         free_extent_map(em);
5014
5015         return 0;
5016 }
5017
5018 static void fill_device_from_item(struct extent_buffer *leaf,
5019                                  struct btrfs_dev_item *dev_item,
5020                                  struct btrfs_device *device)
5021 {
5022         unsigned long ptr;
5023
5024         device->devid = btrfs_device_id(leaf, dev_item);
5025         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
5026         device->total_bytes = device->disk_total_bytes;
5027         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
5028         device->type = btrfs_device_type(leaf, dev_item);
5029         device->io_align = btrfs_device_io_align(leaf, dev_item);
5030         device->io_width = btrfs_device_io_width(leaf, dev_item);
5031         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
5032         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
5033         device->is_tgtdev_for_dev_replace = 0;
5034
5035         ptr = (unsigned long)btrfs_device_uuid(dev_item);
5036         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
5037 }
5038
5039 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
5040 {
5041         struct btrfs_fs_devices *fs_devices;
5042         int ret;
5043
5044         BUG_ON(!mutex_is_locked(&uuid_mutex));
5045
5046         fs_devices = root->fs_info->fs_devices->seed;
5047         while (fs_devices) {
5048                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5049                         ret = 0;
5050                         goto out;
5051                 }
5052                 fs_devices = fs_devices->seed;
5053         }
5054
5055         fs_devices = find_fsid(fsid);
5056         if (!fs_devices) {
5057                 ret = -ENOENT;
5058                 goto out;
5059         }
5060
5061         fs_devices = clone_fs_devices(fs_devices);
5062         if (IS_ERR(fs_devices)) {
5063                 ret = PTR_ERR(fs_devices);
5064                 goto out;
5065         }
5066
5067         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
5068                                    root->fs_info->bdev_holder);
5069         if (ret) {
5070                 free_fs_devices(fs_devices);
5071                 goto out;
5072         }
5073
5074         if (!fs_devices->seeding) {
5075                 __btrfs_close_devices(fs_devices);
5076                 free_fs_devices(fs_devices);
5077                 ret = -EINVAL;
5078                 goto out;
5079         }
5080
5081         fs_devices->seed = root->fs_info->fs_devices->seed;
5082         root->fs_info->fs_devices->seed = fs_devices;
5083 out:
5084         return ret;
5085 }
5086
5087 static int read_one_dev(struct btrfs_root *root,
5088                         struct extent_buffer *leaf,
5089                         struct btrfs_dev_item *dev_item)
5090 {
5091         struct btrfs_device *device;
5092         u64 devid;
5093         int ret;
5094         u8 fs_uuid[BTRFS_UUID_SIZE];
5095         u8 dev_uuid[BTRFS_UUID_SIZE];
5096
5097         devid = btrfs_device_id(leaf, dev_item);
5098         read_extent_buffer(leaf, dev_uuid,
5099                            (unsigned long)btrfs_device_uuid(dev_item),
5100                            BTRFS_UUID_SIZE);
5101         read_extent_buffer(leaf, fs_uuid,
5102                            (unsigned long)btrfs_device_fsid(dev_item),
5103                            BTRFS_UUID_SIZE);
5104
5105         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
5106                 ret = open_seed_devices(root, fs_uuid);
5107                 if (ret && !btrfs_test_opt(root, DEGRADED))
5108                         return ret;
5109         }
5110
5111         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
5112         if (!device || !device->bdev) {
5113                 if (!btrfs_test_opt(root, DEGRADED))
5114                         return -EIO;
5115
5116                 if (!device) {
5117                         printk(KERN_WARNING "warning devid %llu missing\n",
5118                                (unsigned long long)devid);
5119                         device = add_missing_dev(root, devid, dev_uuid);
5120                         if (!device)
5121                                 return -ENOMEM;
5122                 } else if (!device->missing) {
5123                         /*
5124                          * this happens when a device that was properly setup
5125                          * in the device info lists suddenly goes bad.
5126                          * device->bdev is NULL, and so we have to set
5127                          * device->missing to one here
5128                          */
5129                         root->fs_info->fs_devices->missing_devices++;
5130                         device->missing = 1;
5131                 }
5132         }
5133
5134         if (device->fs_devices != root->fs_info->fs_devices) {
5135                 BUG_ON(device->writeable);
5136                 if (device->generation !=
5137                     btrfs_device_generation(leaf, dev_item))
5138                         return -EINVAL;
5139         }
5140
5141         fill_device_from_item(leaf, dev_item, device);
5142         device->dev_root = root->fs_info->dev_root;
5143         device->in_fs_metadata = 1;
5144         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
5145                 device->fs_devices->total_rw_bytes += device->total_bytes;
5146                 spin_lock(&root->fs_info->free_chunk_lock);
5147                 root->fs_info->free_chunk_space += device->total_bytes -
5148                         device->bytes_used;
5149                 spin_unlock(&root->fs_info->free_chunk_lock);
5150         }
5151         ret = 0;
5152         return ret;
5153 }
5154
5155 int btrfs_read_sys_array(struct btrfs_root *root)
5156 {
5157         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
5158         struct extent_buffer *sb;
5159         struct btrfs_disk_key *disk_key;
5160         struct btrfs_chunk *chunk;
5161         u8 *ptr;
5162         unsigned long sb_ptr;
5163         int ret = 0;
5164         u32 num_stripes;
5165         u32 array_size;
5166         u32 len = 0;
5167         u32 cur;
5168         struct btrfs_key key;
5169
5170         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
5171                                           BTRFS_SUPER_INFO_SIZE);
5172         if (!sb)
5173                 return -ENOMEM;
5174         btrfs_set_buffer_uptodate(sb);
5175         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
5176         /*
5177          * The sb extent buffer is artifical and just used to read the system array.
5178          * btrfs_set_buffer_uptodate() call does not properly mark all it's
5179          * pages up-to-date when the page is larger: extent does not cover the
5180          * whole page and consequently check_page_uptodate does not find all
5181          * the page's extents up-to-date (the hole beyond sb),
5182          * write_extent_buffer then triggers a WARN_ON.
5183          *
5184          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
5185          * but sb spans only this function. Add an explicit SetPageUptodate call
5186          * to silence the warning eg. on PowerPC 64.
5187          */
5188         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
5189                 SetPageUptodate(sb->pages[0]);
5190
5191         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
5192         array_size = btrfs_super_sys_array_size(super_copy);
5193
5194         ptr = super_copy->sys_chunk_array;
5195         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
5196         cur = 0;
5197
5198         while (cur < array_size) {
5199                 disk_key = (struct btrfs_disk_key *)ptr;
5200                 btrfs_disk_key_to_cpu(&key, disk_key);
5201
5202                 len = sizeof(*disk_key); ptr += len;
5203                 sb_ptr += len;
5204                 cur += len;
5205
5206                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
5207                         chunk = (struct btrfs_chunk *)sb_ptr;
5208                         ret = read_one_chunk(root, &key, sb, chunk);
5209                         if (ret)
5210                                 break;
5211                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
5212                         len = btrfs_chunk_item_size(num_stripes);
5213                 } else {
5214                         ret = -EIO;
5215                         break;
5216                 }
5217                 ptr += len;
5218                 sb_ptr += len;
5219                 cur += len;
5220         }
5221         free_extent_buffer(sb);
5222         return ret;
5223 }
5224
5225 int btrfs_read_chunk_tree(struct btrfs_root *root)
5226 {
5227         struct btrfs_path *path;
5228         struct extent_buffer *leaf;
5229         struct btrfs_key key;
5230         struct btrfs_key found_key;
5231         int ret;
5232         int slot;
5233
5234         root = root->fs_info->chunk_root;
5235
5236         path = btrfs_alloc_path();
5237         if (!path)
5238                 return -ENOMEM;
5239
5240         mutex_lock(&uuid_mutex);
5241         lock_chunks(root);
5242
5243         /* first we search for all of the device items, and then we
5244          * read in all of the chunk items.  This way we can create chunk
5245          * mappings that reference all of the devices that are afound
5246          */
5247         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
5248         key.offset = 0;
5249         key.type = 0;
5250 again:
5251         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5252         if (ret < 0)
5253                 goto error;
5254         while (1) {
5255                 leaf = path->nodes[0];
5256                 slot = path->slots[0];
5257                 if (slot >= btrfs_header_nritems(leaf)) {
5258                         ret = btrfs_next_leaf(root, path);
5259                         if (ret == 0)
5260                                 continue;
5261                         if (ret < 0)
5262                                 goto error;
5263                         break;
5264                 }
5265                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5266                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5267                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
5268                                 break;
5269                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
5270                                 struct btrfs_dev_item *dev_item;
5271                                 dev_item = btrfs_item_ptr(leaf, slot,
5272                                                   struct btrfs_dev_item);
5273                                 ret = read_one_dev(root, leaf, dev_item);
5274                                 if (ret)
5275                                         goto error;
5276                         }
5277                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
5278                         struct btrfs_chunk *chunk;
5279                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
5280                         ret = read_one_chunk(root, &found_key, leaf, chunk);
5281                         if (ret)
5282                                 goto error;
5283                 }
5284                 path->slots[0]++;
5285         }
5286         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5287                 key.objectid = 0;
5288                 btrfs_release_path(path);
5289                 goto again;
5290         }
5291         ret = 0;
5292 error:
5293         unlock_chunks(root);
5294         mutex_unlock(&uuid_mutex);
5295
5296         btrfs_free_path(path);
5297         return ret;
5298 }
5299
5300 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
5301 {
5302         int i;
5303
5304         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5305                 btrfs_dev_stat_reset(dev, i);
5306 }
5307
5308 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
5309 {
5310         struct btrfs_key key;
5311         struct btrfs_key found_key;
5312         struct btrfs_root *dev_root = fs_info->dev_root;
5313         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5314         struct extent_buffer *eb;
5315         int slot;
5316         int ret = 0;
5317         struct btrfs_device *device;
5318         struct btrfs_path *path = NULL;
5319         int i;
5320
5321         path = btrfs_alloc_path();
5322         if (!path) {
5323                 ret = -ENOMEM;
5324                 goto out;
5325         }
5326
5327         mutex_lock(&fs_devices->device_list_mutex);
5328         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5329                 int item_size;
5330                 struct btrfs_dev_stats_item *ptr;
5331
5332                 key.objectid = 0;
5333                 key.type = BTRFS_DEV_STATS_KEY;
5334                 key.offset = device->devid;
5335                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
5336                 if (ret) {
5337                         __btrfs_reset_dev_stats(device);
5338                         device->dev_stats_valid = 1;
5339                         btrfs_release_path(path);
5340                         continue;
5341                 }
5342                 slot = path->slots[0];
5343                 eb = path->nodes[0];
5344                 btrfs_item_key_to_cpu(eb, &found_key, slot);
5345                 item_size = btrfs_item_size_nr(eb, slot);
5346
5347                 ptr = btrfs_item_ptr(eb, slot,
5348                                      struct btrfs_dev_stats_item);
5349
5350                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5351                         if (item_size >= (1 + i) * sizeof(__le64))
5352                                 btrfs_dev_stat_set(device, i,
5353                                         btrfs_dev_stats_value(eb, ptr, i));
5354                         else
5355                                 btrfs_dev_stat_reset(device, i);
5356                 }
5357
5358                 device->dev_stats_valid = 1;
5359                 btrfs_dev_stat_print_on_load(device);
5360                 btrfs_release_path(path);
5361         }
5362         mutex_unlock(&fs_devices->device_list_mutex);
5363
5364 out:
5365         btrfs_free_path(path);
5366         return ret < 0 ? ret : 0;
5367 }
5368
5369 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
5370                                 struct btrfs_root *dev_root,
5371                                 struct btrfs_device *device)
5372 {
5373         struct btrfs_path *path;
5374         struct btrfs_key key;
5375         struct extent_buffer *eb;
5376         struct btrfs_dev_stats_item *ptr;
5377         int ret;
5378         int i;
5379
5380         key.objectid = 0;
5381         key.type = BTRFS_DEV_STATS_KEY;
5382         key.offset = device->devid;
5383
5384         path = btrfs_alloc_path();
5385         BUG_ON(!path);
5386         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
5387         if (ret < 0) {
5388                 printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
5389                               ret, rcu_str_deref(device->name));
5390                 goto out;
5391         }
5392
5393         if (ret == 0 &&
5394             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
5395                 /* need to delete old one and insert a new one */
5396                 ret = btrfs_del_item(trans, dev_root, path);
5397                 if (ret != 0) {
5398                         printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
5399                                       rcu_str_deref(device->name), ret);
5400                         goto out;
5401                 }
5402                 ret = 1;
5403         }
5404
5405         if (ret == 1) {
5406                 /* need to insert a new item */
5407                 btrfs_release_path(path);
5408                 ret = btrfs_insert_empty_item(trans, dev_root, path,
5409                                               &key, sizeof(*ptr));
5410                 if (ret < 0) {
5411                         printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
5412                                       rcu_str_deref(device->name), ret);
5413                         goto out;
5414                 }
5415         }
5416
5417         eb = path->nodes[0];
5418         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
5419         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5420                 btrfs_set_dev_stats_value(eb, ptr, i,
5421                                           btrfs_dev_stat_read(device, i));
5422         btrfs_mark_buffer_dirty(eb);
5423
5424 out:
5425         btrfs_free_path(path);
5426         return ret;
5427 }
5428
5429 /*
5430  * called from commit_transaction. Writes all changed device stats to disk.
5431  */
5432 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
5433                         struct btrfs_fs_info *fs_info)
5434 {
5435         struct btrfs_root *dev_root = fs_info->dev_root;
5436         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5437         struct btrfs_device *device;
5438         int ret = 0;
5439
5440         mutex_lock(&fs_devices->device_list_mutex);
5441         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5442                 if (!device->dev_stats_valid || !device->dev_stats_dirty)
5443                         continue;
5444
5445                 ret = update_dev_stat_item(trans, dev_root, device);
5446                 if (!ret)
5447                         device->dev_stats_dirty = 0;
5448         }
5449         mutex_unlock(&fs_devices->device_list_mutex);
5450
5451         return ret;
5452 }
5453
5454 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
5455 {
5456         btrfs_dev_stat_inc(dev, index);
5457         btrfs_dev_stat_print_on_error(dev);
5458 }
5459
5460 void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
5461 {
5462         if (!dev->dev_stats_valid)
5463                 return;
5464         printk_ratelimited_in_rcu(KERN_ERR
5465                            "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5466                            rcu_str_deref(dev->name),
5467                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5468                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5469                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5470                            btrfs_dev_stat_read(dev,
5471                                                BTRFS_DEV_STAT_CORRUPTION_ERRS),
5472                            btrfs_dev_stat_read(dev,
5473                                                BTRFS_DEV_STAT_GENERATION_ERRS));
5474 }
5475
5476 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
5477 {
5478         int i;
5479
5480         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5481                 if (btrfs_dev_stat_read(dev, i) != 0)
5482                         break;
5483         if (i == BTRFS_DEV_STAT_VALUES_MAX)
5484                 return; /* all values == 0, suppress message */
5485
5486         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5487                rcu_str_deref(dev->name),
5488                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5489                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5490                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5491                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
5492                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
5493 }
5494
5495 int btrfs_get_dev_stats(struct btrfs_root *root,
5496                         struct btrfs_ioctl_get_dev_stats *stats)
5497 {
5498         struct btrfs_device *dev;
5499         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5500         int i;
5501
5502         mutex_lock(&fs_devices->device_list_mutex);
5503         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
5504         mutex_unlock(&fs_devices->device_list_mutex);
5505
5506         if (!dev) {
5507                 printk(KERN_WARNING
5508                        "btrfs: get dev_stats failed, device not found\n");
5509                 return -ENODEV;
5510         } else if (!dev->dev_stats_valid) {
5511                 printk(KERN_WARNING
5512                        "btrfs: get dev_stats failed, not yet valid\n");
5513                 return -ENODEV;
5514         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
5515                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5516                         if (stats->nr_items > i)
5517                                 stats->values[i] =
5518                                         btrfs_dev_stat_read_and_reset(dev, i);
5519                         else
5520                                 btrfs_dev_stat_reset(dev, i);
5521                 }
5522         } else {
5523                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5524                         if (stats->nr_items > i)
5525                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
5526         }
5527         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
5528                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
5529         return 0;
5530 }
5531
5532 int btrfs_scratch_superblock(struct btrfs_device *device)
5533 {
5534         struct buffer_head *bh;
5535         struct btrfs_super_block *disk_super;
5536
5537         bh = btrfs_read_dev_super(device->bdev);
5538         if (!bh)
5539                 return -EINVAL;
5540         disk_super = (struct btrfs_super_block *)bh->b_data;
5541
5542         memset(&disk_super->magic, 0, sizeof(disk_super->magic));
5543         set_buffer_dirty(bh);
5544         sync_dirty_buffer(bh);
5545         brelse(bh);
5546
5547         return 0;
5548 }