fs/btrfs/check-integrity.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) STRATO AG 2011.  All rights reserved.
   4  */
   5
   6 /*
   7  * This module can be used to catch cases when the btrfs kernel
   8  * code executes write requests to the disk that bring the file
   9  * system in an inconsistent state. In such a state, a power-loss
  10  * or kernel panic event would cause that the data on disk is
  11  * lost or at least damaged.
  12  *
  13  * Code is added that examines all block write requests during
  14  * runtime (including writes of the super block). Three rules
  15  * are verified and an error is printed on violation of the
  16  * rules:
  17  * 1. It is not allowed to write a disk block which is
  18  *    currently referenced by the super block (either directly
  19  *    or indirectly).
  20  * 2. When a super block is written, it is verified that all
  21  *    referenced (directly or indirectly) blocks fulfill the
  22  *    following requirements:
  23  *    2a. All referenced blocks have either been present when
  24  *        the file system was mounted, (i.e., they have been
  25  *        referenced by the super block) or they have been
  26  *        written since then and the write completion callback
  27  *        was called and no write error was indicated and a
  28  *        FLUSH request to the device where these blocks are
  29  *        located was received and completed.
  30  *    2b. All referenced blocks need to have a generation
  31  *        number which is equal to the parent's number.
  32  *
  33  * One issue that was found using this module was that the log
  34  * tree on disk became temporarily corrupted because disk blocks
  35  * that had been in use for the log tree had been freed and
  36  * reused too early, while being referenced by the written super
  37  * block.
  38  *
  39  * The search term in the kernel log that can be used to filter
  40  * on the existence of detected integrity issues is
  41  * "btrfs: attempt".
  42  *
  43  * The integrity check is enabled via mount options. These
  44  * mount options are only supported if the integrity check
  45  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  46  *
  47  * Example #1, apply integrity checks to all metadata:
  48  * mount /dev/sdb1 /mnt -o check_int
  49  *
  50  * Example #2, apply integrity checks to all metadata and
  51  * to data extents:
  52  * mount /dev/sdb1 /mnt -o check_int_data
  53  *
  54  * Example #3, apply integrity checks to all metadata and dump
  55  * the tree that the super block references to kernel messages
  56  * each time after a super block was written:
  57  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  58  *
  59  * If the integrity check tool is included and activated in
  60  * the mount options, plenty of kernel memory is used, and
  61  * plenty of additional CPU cycles are spent. Enabling this
  62  * functionality is not intended for normal use. In most
  63  * cases, unless you are a btrfs developer who needs to verify
  64  * the integrity of (super)-block write requests, do not
  65  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  66  * include and compile the integrity check tool.
  67  *
  68  * Expect millions of lines of information in the kernel log with an
  69  * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
  70  * kernel config to at least 26 (which is 64MB). Usually the value is
  71  * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
  72  * changed like this before LOG_BUF_SHIFT can be set to a high value:
  73  * config LOG_BUF_SHIFT
  74  *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  75  *       range 12 30
  76  */
  77
  78 #include <linux/sched.h>
  79 #include <linux/slab.h>
  80 #include <linux/mutex.h>
  81 #include <linux/blkdev.h>
  82 #include <linux/mm.h>
  83 #include <linux/string.h>
  84 #include <crypto/hash.h>
  85 #include "ctree.h"
  86 #include "disk-io.h"
  87 #include "transaction.h"
  88 #include "extent_io.h"
  89 #include "volumes.h"
  90 #include "print-tree.h"
  91 #include "locking.h"
  92 #include "check-integrity.h"
  93 #include "rcu-string.h"
  94 #include "compression.h"
  95
  96 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
  97 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
  98 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
  99 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 100 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 101 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 102 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 103 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 104                                                          * excluding " [...]" */
 105 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 106
 107 /*
 108  * The definition of the bitmask fields for the print_mask.
 109  * They are specified with the mount option check_integrity_print_mask.
 110  */
 111 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 112 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 113 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 114 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 115 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 116 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 117 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 118 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 119 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 120 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 121 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 122 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 123 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 124 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
 125
 126 struct btrfsic_dev_state;
 127 struct btrfsic_state;
 128
 129 struct btrfsic_block {
 130         u32 magic_num;          /* only used for debug purposes */
 131         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 132         unsigned int is_superblock:1;   /* if it is one of the superblocks */
 133         unsigned int is_iodone:1;       /* if is done by lower subsystem */
 134         unsigned int iodone_w_error:1;  /* error was indicated to endio */
 135         unsigned int never_written:1;   /* block was added because it was
 136                                          * referenced, not because it was
 137                                          * written */
 138         unsigned int mirror_num;        /* large enough to hold
 139                                          * BTRFS_SUPER_MIRROR_MAX */
 140         struct btrfsic_dev_state *dev_state;
 141         u64 dev_bytenr;         /* key, physical byte num on disk */
 142         u64 logical_bytenr;     /* logical byte num on disk */
 143         u64 generation;
 144         struct btrfs_disk_key disk_key; /* extra info to print in case of
 145                                          * issues, will not always be correct */
 146         struct list_head collision_resolving_node;      /* list node */
 147         struct list_head all_blocks_node;       /* list node */
 148
 149         /* the following two lists contain block_link items */
 150         struct list_head ref_to_list;   /* list */
 151         struct list_head ref_from_list; /* list */
 152         struct btrfsic_block *next_in_same_bio;
 153         void *orig_bio_private;
 154         bio_end_io_t *orig_bio_end_io;
 155         int submit_bio_bh_rw;
 156         u64 flush_gen; /* only valid if !never_written */
 157 };
 158
 159 /*
 160  * Elements of this type are allocated dynamically and required because
 161  * each block object can refer to and can be ref from multiple blocks.
 162  * The key to lookup them in the hashtable is the dev_bytenr of
 163  * the block ref to plus the one from the block referred from.
 164  * The fact that they are searchable via a hashtable and that a
 165  * ref_cnt is maintained is not required for the btrfs integrity
 166  * check algorithm itself, it is only used to make the output more
 167  * beautiful in case that an error is detected (an error is defined
 168  * as a write operation to a block while that block is still referenced).
 169  */
 170 struct btrfsic_block_link {
 171         u32 magic_num;          /* only used for debug purposes */
 172         u32 ref_cnt;
 173         struct list_head node_ref_to;   /* list node */
 174         struct list_head node_ref_from; /* list node */
 175         struct list_head collision_resolving_node;      /* list node */
 176         struct btrfsic_block *block_ref_to;
 177         struct btrfsic_block *block_ref_from;
 178         u64 parent_generation;
 179 };
 180
 181 struct btrfsic_dev_state {
 182         u32 magic_num;          /* only used for debug purposes */
 183         struct block_device *bdev;
 184         struct btrfsic_state *state;
 185         struct list_head collision_resolving_node;      /* list node */
 186         struct btrfsic_block dummy_block_for_bio_bh_flush;
 187         u64 last_flush_gen;
 188 };
 189
 190 struct btrfsic_block_hashtable {
 191         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 192 };
 193
 194 struct btrfsic_block_link_hashtable {
 195         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 196 };
 197
 198 struct btrfsic_dev_state_hashtable {
 199         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 200 };
 201
 202 struct btrfsic_block_data_ctx {
 203         u64 start;              /* virtual bytenr */
 204         u64 dev_bytenr;         /* physical bytenr on device */
 205         u32 len;
 206         struct btrfsic_dev_state *dev;
 207         char **datav;
 208         struct page **pagev;
 209         void *mem_to_free;
 210 };
 211
 212 /* This structure is used to implement recursion without occupying
 213  * any stack space, refer to btrfsic_process_metablock() */
 214 struct btrfsic_stack_frame {
 215         u32 magic;
 216         u32 nr;
 217         int error;
 218         int i;
 219         int limit_nesting;
 220         int num_copies;
 221         int mirror_num;
 222         struct btrfsic_block *block;
 223         struct btrfsic_block_data_ctx *block_ctx;
 224         struct btrfsic_block *next_block;
 225         struct btrfsic_block_data_ctx next_block_ctx;
 226         struct btrfs_header *hdr;
 227         struct btrfsic_stack_frame *prev;
 228 };
 229
 230 /* Some state per mounted filesystem */
 231 struct btrfsic_state {
 232         u32 print_mask;
 233         int include_extent_data;
 234         struct list_head all_blocks_list;
 235         struct btrfsic_block_hashtable block_hashtable;
 236         struct btrfsic_block_link_hashtable block_link_hashtable;
 237         struct btrfs_fs_info *fs_info;
 238         u64 max_superblock_generation;
 239         struct btrfsic_block *latest_superblock;
 240         u32 metablock_size;
 241         u32 datablock_size;
 242 };
 243
 244 static int btrfsic_process_metablock(struct btrfsic_state *state,
 245                                      struct btrfsic_block *block,
 246                                      struct btrfsic_block_data_ctx *block_ctx,
 247                                      int limit_nesting, int force_iodone_flag);
 248 static void btrfsic_read_from_block_data(
 249         struct btrfsic_block_data_ctx *block_ctx,
 250         void *dst, u32 offset, size_t len);
 251 static int btrfsic_create_link_to_next_block(
 252                 struct btrfsic_state *state,
 253                 struct btrfsic_block *block,
 254                 struct btrfsic_block_data_ctx
 255                 *block_ctx, u64 next_bytenr,
 256                 int limit_nesting,
 257                 struct btrfsic_block_data_ctx *next_block_ctx,
 258                 struct btrfsic_block **next_blockp,
 259                 int force_iodone_flag,
 260                 int *num_copiesp, int *mirror_nump,
 261                 struct btrfs_disk_key *disk_key,
 262                 u64 parent_generation);
 263 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 264                                       struct btrfsic_block *block,
 265                                       struct btrfsic_block_data_ctx *block_ctx,
 266                                       u32 item_offset, int force_iodone_flag);
 267 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 268                              struct btrfsic_block_data_ctx *block_ctx_out,
 269                              int mirror_num);
 270 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 271 static int btrfsic_read_block(struct btrfsic_state *state,
 272                               struct btrfsic_block_data_ctx *block_ctx);
 273 static int btrfsic_process_written_superblock(
 274                 struct btrfsic_state *state,
 275                 struct btrfsic_block *const block,
 276                 struct btrfs_super_block *const super_hdr);
 277 static void btrfsic_bio_end_io(struct bio *bp);
 278 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 279                                               const struct btrfsic_block *block,
 280                                               int recursion_level);
 281 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 282                                         struct btrfsic_block *const block,
 283                                         int recursion_level);
 284 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 285                                    const struct btrfsic_block_link *l);
 286 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 287                                    const struct btrfsic_block_link *l);
 288 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 289                                    const struct btrfsic_block *block);
 290 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 291 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 292                                   const struct btrfsic_block *block,
 293                                   int indent_level);
 294 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 295                 struct btrfsic_state *state,
 296                 struct btrfsic_block_data_ctx *next_block_ctx,
 297                 struct btrfsic_block *next_block,
 298                 struct btrfsic_block *from_block,
 299                 u64 parent_generation);
 300 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 301                 struct btrfsic_state *state,
 302                 struct btrfsic_block_data_ctx *block_ctx,
 303                 const char *additional_string,
 304                 int is_metadata,
 305                 int is_iodone,
 306                 int never_written,
 307                 int mirror_num,
 308                 int *was_created);
 309 static int btrfsic_process_superblock_dev_mirror(
 310                 struct btrfsic_state *state,
 311                 struct btrfsic_dev_state *dev_state,
 312                 struct btrfs_device *device,
 313                 int superblock_mirror_num,
 314                 struct btrfsic_dev_state **selected_dev_state,
 315                 struct btrfs_super_block *selected_super);
 316 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
 317 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 318                                            u64 bytenr,
 319                                            struct btrfsic_dev_state *dev_state,
 320                                            u64 dev_bytenr);
 321
 322 static struct mutex btrfsic_mutex;
 323 static int btrfsic_is_initialized;
 324 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 325
 326
 327 static void btrfsic_block_init(struct btrfsic_block *b)
 328 {
 329         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 330         b->dev_state = NULL;
 331         b->dev_bytenr = 0;
 332         b->logical_bytenr = 0;
 333         b->generation = BTRFSIC_GENERATION_UNKNOWN;
 334         b->disk_key.objectid = 0;
 335         b->disk_key.type = 0;
 336         b->disk_key.offset = 0;
 337         b->is_metadata = 0;
 338         b->is_superblock = 0;
 339         b->is_iodone = 0;
 340         b->iodone_w_error = 0;
 341         b->never_written = 0;
 342         b->mirror_num = 0;
 343         b->next_in_same_bio = NULL;
 344         b->orig_bio_private = NULL;
 345         b->orig_bio_end_io = NULL;
 346         INIT_LIST_HEAD(&b->collision_resolving_node);
 347         INIT_LIST_HEAD(&b->all_blocks_node);
 348         INIT_LIST_HEAD(&b->ref_to_list);
 349         INIT_LIST_HEAD(&b->ref_from_list);
 350         b->submit_bio_bh_rw = 0;
 351         b->flush_gen = 0;
 352 }
 353
 354 static struct btrfsic_block *btrfsic_block_alloc(void)
 355 {
 356         struct btrfsic_block *b;
 357
 358         b = kzalloc(sizeof(*b), GFP_NOFS);
 359         if (NULL != b)
 360                 btrfsic_block_init(b);
 361
 362         return b;
 363 }
 364
 365 static void btrfsic_block_free(struct btrfsic_block *b)
 366 {
 367         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 368         kfree(b);
 369 }
 370
 371 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 372 {
 373         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 374         l->ref_cnt = 1;
 375         INIT_LIST_HEAD(&l->node_ref_to);
 376         INIT_LIST_HEAD(&l->node_ref_from);
 377         INIT_LIST_HEAD(&l->collision_resolving_node);
 378         l->block_ref_to = NULL;
 379         l->block_ref_from = NULL;
 380 }
 381
 382 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 383 {
 384         struct btrfsic_block_link *l;
 385
 386         l = kzalloc(sizeof(*l), GFP_NOFS);
 387         if (NULL != l)
 388                 btrfsic_block_link_init(l);
 389
 390         return l;
 391 }
 392
 393 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 394 {
 395         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 396         kfree(l);
 397 }
 398
 399 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 400 {
 401         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 402         ds->bdev = NULL;
 403         ds->state = NULL;
 404         INIT_LIST_HEAD(&ds->collision_resolving_node);
 405         ds->last_flush_gen = 0;
 406         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 407         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 408         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 409 }
 410
 411 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 412 {
 413         struct btrfsic_dev_state *ds;
 414
 415         ds = kzalloc(sizeof(*ds), GFP_NOFS);
 416         if (NULL != ds)
 417                 btrfsic_dev_state_init(ds);
 418
 419         return ds;
 420 }
 421
 422 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 423 {
 424         BUG_ON(!(NULL == ds ||
 425                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 426         kfree(ds);
 427 }
 428
 429 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 430 {
 431         int i;
 432
 433         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 434                 INIT_LIST_HEAD(h->table + i);
 435 }
 436
 437 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 438                                         struct btrfsic_block_hashtable *h)
 439 {
 440         const unsigned int hashval =
 441             (((unsigned int)(b->dev_bytenr >> 16)) ^
 442              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 443              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 444
 445         list_add(&b->collision_resolving_node, h->table + hashval);
 446 }
 447
 448 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 449 {
 450         list_del(&b->collision_resolving_node);
 451 }
 452
 453 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 454                 struct block_device *bdev,
 455                 u64 dev_bytenr,
 456                 struct btrfsic_block_hashtable *h)
 457 {
 458         const unsigned int hashval =
 459             (((unsigned int)(dev_bytenr >> 16)) ^
 460              ((unsigned int)((uintptr_t)bdev))) &
 461              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 462         struct btrfsic_block *b;
 463
 464         list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
 465                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 466                         return b;
 467         }
 468
 469         return NULL;
 470 }
 471
 472 static void btrfsic_block_link_hashtable_init(
 473                 struct btrfsic_block_link_hashtable *h)
 474 {
 475         int i;
 476
 477         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 478                 INIT_LIST_HEAD(h->table + i);
 479 }
 480
 481 static void btrfsic_block_link_hashtable_add(
 482                 struct btrfsic_block_link *l,
 483                 struct btrfsic_block_link_hashtable *h)
 484 {
 485         const unsigned int hashval =
 486             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 487              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 488              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 489              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 490              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 491
 492         BUG_ON(NULL == l->block_ref_to);
 493         BUG_ON(NULL == l->block_ref_from);
 494         list_add(&l->collision_resolving_node, h->table + hashval);
 495 }
 496
 497 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 498 {
 499         list_del(&l->collision_resolving_node);
 500 }
 501
 502 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 503                 struct block_device *bdev_ref_to,
 504                 u64 dev_bytenr_ref_to,
 505                 struct block_device *bdev_ref_from,
 506                 u64 dev_bytenr_ref_from,
 507                 struct btrfsic_block_link_hashtable *h)
 508 {
 509         const unsigned int hashval =
 510             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 511              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 512              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 513              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 514              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 515         struct btrfsic_block_link *l;
 516
 517         list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
 518                 BUG_ON(NULL == l->block_ref_to);
 519                 BUG_ON(NULL == l->block_ref_from);
 520                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 521                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 522                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 523                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 524                         return l;
 525         }
 526
 527         return NULL;
 528 }
 529
 530 static void btrfsic_dev_state_hashtable_init(
 531                 struct btrfsic_dev_state_hashtable *h)
 532 {
 533         int i;
 534
 535         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 536                 INIT_LIST_HEAD(h->table + i);
 537 }
 538
 539 static void btrfsic_dev_state_hashtable_add(
 540                 struct btrfsic_dev_state *ds,
 541                 struct btrfsic_dev_state_hashtable *h)
 542 {
 543         const unsigned int hashval =
 544             (((unsigned int)((uintptr_t)ds->bdev->bd_dev)) &
 545              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 546
 547         list_add(&ds->collision_resolving_node, h->table + hashval);
 548 }
 549
 550 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 551 {
 552         list_del(&ds->collision_resolving_node);
 553 }
 554
 555 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 556                 struct btrfsic_dev_state_hashtable *h)
 557 {
 558         const unsigned int hashval =
 559                 dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
 560         struct btrfsic_dev_state *ds;
 561
 562         list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
 563                 if (ds->bdev->bd_dev == dev)
 564                         return ds;
 565         }
 566
 567         return NULL;
 568 }
 569
 570 static int btrfsic_process_superblock(struct btrfsic_state *state,
 571                                       struct btrfs_fs_devices *fs_devices)
 572 {
 573         struct btrfs_super_block *selected_super;
 574         struct list_head *dev_head = &fs_devices->devices;
 575         struct btrfs_device *device;
 576         struct btrfsic_dev_state *selected_dev_state = NULL;
 577         int ret = 0;
 578         int pass;
 579
 580         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 581         if (!selected_super)
 582                 return -ENOMEM;
 583
 584         list_for_each_entry(device, dev_head, dev_list) {
 585                 int i;
 586                 struct btrfsic_dev_state *dev_state;
 587
 588                 if (!device->bdev || !device->name)
 589                         continue;
 590
 591                 dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 592                 BUG_ON(NULL == dev_state);
 593                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 594                         ret = btrfsic_process_superblock_dev_mirror(
 595                                         state, dev_state, device, i,
 596                                         &selected_dev_state, selected_super);
 597                         if (0 != ret && 0 == i) {
 598                                 kfree(selected_super);
 599                                 return ret;
 600                         }
 601                 }
 602         }
 603
 604         if (NULL == state->latest_superblock) {
 605                 pr_info("btrfsic: no superblock found!\n");
 606                 kfree(selected_super);
 607                 return -1;
 608         }
 609
 610         for (pass = 0; pass < 3; pass++) {
 611                 int num_copies;
 612                 int mirror_num;
 613                 u64 next_bytenr;
 614
 615                 switch (pass) {
 616                 case 0:
 617                         next_bytenr = btrfs_super_root(selected_super);
 618                         if (state->print_mask &
 619                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 620                                 pr_info("root@%llu\n", next_bytenr);
 621                         break;
 622                 case 1:
 623                         next_bytenr = btrfs_super_chunk_root(selected_super);
 624                         if (state->print_mask &
 625                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 626                                 pr_info("chunk@%llu\n", next_bytenr);
 627                         break;
 628                 case 2:
 629                         next_bytenr = btrfs_super_log_root(selected_super);
 630                         if (0 == next_bytenr)
 631                                 continue;
 632                         if (state->print_mask &
 633                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 634                                 pr_info("log@%llu\n", next_bytenr);
 635                         break;
 636                 }
 637
 638                 num_copies = btrfs_num_copies(state->fs_info, next_bytenr,
 639                                               state->metablock_size);
 640                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 641                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 642                                next_bytenr, num_copies);
 643
 644                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 645                         struct btrfsic_block *next_block;
 646                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 647                         struct btrfsic_block_link *l;
 648
 649                         ret = btrfsic_map_block(state, next_bytenr,
 650                                                 state->metablock_size,
 651                                                 &tmp_next_block_ctx,
 652                                                 mirror_num);
 653                         if (ret) {
 654                                 pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
 655                                        next_bytenr, mirror_num);
 656                                 kfree(selected_super);
 657                                 return -1;
 658                         }
 659
 660                         next_block = btrfsic_block_hashtable_lookup(
 661                                         tmp_next_block_ctx.dev->bdev,
 662                                         tmp_next_block_ctx.dev_bytenr,
 663                                         &state->block_hashtable);
 664                         BUG_ON(NULL == next_block);
 665
 666                         l = btrfsic_block_link_hashtable_lookup(
 667                                         tmp_next_block_ctx.dev->bdev,
 668                                         tmp_next_block_ctx.dev_bytenr,
 669                                         state->latest_superblock->dev_state->
 670                                         bdev,
 671                                         state->latest_superblock->dev_bytenr,
 672                                         &state->block_link_hashtable);
 673                         BUG_ON(NULL == l);
 674
 675                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 676                         if (ret < (int)PAGE_SIZE) {
 677                                 pr_info("btrfsic: read @logical %llu failed!\n",
 678                                        tmp_next_block_ctx.start);
 679                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 680                                 kfree(selected_super);
 681                                 return -1;
 682                         }
 683
 684                         ret = btrfsic_process_metablock(state,
 685                                                         next_block,
 686                                                         &tmp_next_block_ctx,
 687                                                         BTRFS_MAX_LEVEL + 3, 1);
 688                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 689                 }
 690         }
 691
 692         kfree(selected_super);
 693         return ret;
 694 }
 695
 696 static int btrfsic_process_superblock_dev_mirror(
 697                 struct btrfsic_state *state,
 698                 struct btrfsic_dev_state *dev_state,
 699                 struct btrfs_device *device,
 700                 int superblock_mirror_num,
 701                 struct btrfsic_dev_state **selected_dev_state,
 702                 struct btrfs_super_block *selected_super)
 703 {
 704         struct btrfs_fs_info *fs_info = state->fs_info;
 705         struct btrfs_super_block *super_tmp;
 706         u64 dev_bytenr;
 707         struct btrfsic_block *superblock_tmp;
 708         int pass;
 709         struct block_device *const superblock_bdev = device->bdev;
 710         struct page *page;
 711         struct address_space *mapping = superblock_bdev->bd_inode->i_mapping;
 712         int ret = 0;
 713
 714         /* super block bytenr is always the unmapped device bytenr */
 715         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 716         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 717                 return -1;
 718
 719         page = read_cache_page_gfp(mapping, dev_bytenr >> PAGE_SHIFT, GFP_NOFS);
 720         if (IS_ERR(page))
 721                 return -1;
 722
 723         super_tmp = page_address(page);
 724
 725         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 726             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 727             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 728             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 729             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 730                 ret = 0;
 731                 goto out;
 732         }
 733
 734         superblock_tmp =
 735             btrfsic_block_hashtable_lookup(superblock_bdev,
 736                                            dev_bytenr,
 737                                            &state->block_hashtable);
 738         if (NULL == superblock_tmp) {
 739                 superblock_tmp = btrfsic_block_alloc();
 740                 if (NULL == superblock_tmp) {
 741                         ret = -1;
 742                         goto out;
 743                 }
 744                 /* for superblock, only the dev_bytenr makes sense */
 745                 superblock_tmp->dev_bytenr = dev_bytenr;
 746                 superblock_tmp->dev_state = dev_state;
 747                 superblock_tmp->logical_bytenr = dev_bytenr;
 748                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 749                 superblock_tmp->is_metadata = 1;
 750                 superblock_tmp->is_superblock = 1;
 751                 superblock_tmp->is_iodone = 1;
 752                 superblock_tmp->never_written = 0;
 753                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 754                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 755                         btrfs_info_in_rcu(fs_info,
 756                         "new initial S-block (bdev %p, %s) @%llu (%pg/%llu/%d)",
 757                                      superblock_bdev,
 758                                      rcu_str_deref(device->name), dev_bytenr,
 759                                      dev_state->bdev, dev_bytenr,
 760                                      superblock_mirror_num);
 761                 list_add(&superblock_tmp->all_blocks_node,
 762                          &state->all_blocks_list);
 763                 btrfsic_block_hashtable_add(superblock_tmp,
 764                                             &state->block_hashtable);
 765         }
 766
 767         /* select the one with the highest generation field */
 768         if (btrfs_super_generation(super_tmp) >
 769             state->max_superblock_generation ||
 770             0 == state->max_superblock_generation) {
 771                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 772                 *selected_dev_state = dev_state;
 773                 state->max_superblock_generation =
 774                     btrfs_super_generation(super_tmp);
 775                 state->latest_superblock = superblock_tmp;
 776         }
 777
 778         for (pass = 0; pass < 3; pass++) {
 779                 u64 next_bytenr;
 780                 int num_copies;
 781                 int mirror_num;
 782                 const char *additional_string = NULL;
 783                 struct btrfs_disk_key tmp_disk_key;
 784
 785                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 786                 tmp_disk_key.offset = 0;
 787                 switch (pass) {
 788                 case 0:
 789                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 790                                                     BTRFS_ROOT_TREE_OBJECTID);
 791                         additional_string = "initial root ";
 792                         next_bytenr = btrfs_super_root(super_tmp);
 793                         break;
 794                 case 1:
 795                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 796                                                     BTRFS_CHUNK_TREE_OBJECTID);
 797                         additional_string = "initial chunk ";
 798                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 799                         break;
 800                 case 2:
 801                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 802                                                     BTRFS_TREE_LOG_OBJECTID);
 803                         additional_string = "initial log ";
 804                         next_bytenr = btrfs_super_log_root(super_tmp);
 805                         if (0 == next_bytenr)
 806                                 continue;
 807                         break;
 808                 }
 809
 810                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
 811                                               state->metablock_size);
 812                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 813                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 814                                next_bytenr, num_copies);
 815                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 816                         struct btrfsic_block *next_block;
 817                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 818                         struct btrfsic_block_link *l;
 819
 820                         if (btrfsic_map_block(state, next_bytenr,
 821                                               state->metablock_size,
 822                                               &tmp_next_block_ctx,
 823                                               mirror_num)) {
 824                                 pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
 825                                        next_bytenr, mirror_num);
 826                                 ret = -1;
 827                                 goto out;
 828                         }
 829
 830                         next_block = btrfsic_block_lookup_or_add(
 831                                         state, &tmp_next_block_ctx,
 832                                         additional_string, 1, 1, 0,
 833                                         mirror_num, NULL);
 834                         if (NULL == next_block) {
 835                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 836                                 ret = -1;
 837                                 goto out;
 838                         }
 839
 840                         next_block->disk_key = tmp_disk_key;
 841                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 842                         l = btrfsic_block_link_lookup_or_add(
 843                                         state, &tmp_next_block_ctx,
 844                                         next_block, superblock_tmp,
 845                                         BTRFSIC_GENERATION_UNKNOWN);
 846                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 847                         if (NULL == l) {
 848                                 ret = -1;
 849                                 goto out;
 850                         }
 851                 }
 852         }
 853         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 854                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 855
 856 out:
 857         put_page(page);
 858         return ret;
 859 }
 860
 861 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 862 {
 863         struct btrfsic_stack_frame *sf;
 864
 865         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 866         if (sf)
 867                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 868         return sf;
 869 }
 870
 871 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 872 {
 873         BUG_ON(!(NULL == sf ||
 874                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 875         kfree(sf);
 876 }
 877
 878 static noinline_for_stack int btrfsic_process_metablock(
 879                 struct btrfsic_state *state,
 880                 struct btrfsic_block *const first_block,
 881                 struct btrfsic_block_data_ctx *const first_block_ctx,
 882                 int first_limit_nesting, int force_iodone_flag)
 883 {
 884         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 885         struct btrfsic_stack_frame *sf;
 886         struct btrfsic_stack_frame *next_stack;
 887         struct btrfs_header *const first_hdr =
 888                 (struct btrfs_header *)first_block_ctx->datav[0];
 889
 890         BUG_ON(!first_hdr);
 891         sf = &initial_stack_frame;
 892         sf->error = 0;
 893         sf->i = -1;
 894         sf->limit_nesting = first_limit_nesting;
 895         sf->block = first_block;
 896         sf->block_ctx = first_block_ctx;
 897         sf->next_block = NULL;
 898         sf->hdr = first_hdr;
 899         sf->prev = NULL;
 900
 901 continue_with_new_stack_frame:
 902         sf->block->generation = btrfs_stack_header_generation(sf->hdr);
 903         if (0 == sf->hdr->level) {
 904                 struct btrfs_leaf *const leafhdr =
 905                     (struct btrfs_leaf *)sf->hdr;
 906
 907                 if (-1 == sf->i) {
 908                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
 909
 910                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 911                                 pr_info("leaf %llu items %d generation %llu owner %llu\n",
 912                                        sf->block_ctx->start, sf->nr,
 913                                        btrfs_stack_header_generation(
 914                                                &leafhdr->header),
 915                                        btrfs_stack_header_owner(
 916                                                &leafhdr->header));
 917                 }
 918
 919 continue_with_current_leaf_stack_frame:
 920                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
 921                         sf->i++;
 922                         sf->num_copies = 0;
 923                 }
 924
 925                 if (sf->i < sf->nr) {
 926                         struct btrfs_item disk_item;
 927                         u32 disk_item_offset =
 928                                 (uintptr_t)(leafhdr->items + sf->i) -
 929                                 (uintptr_t)leafhdr;
 930                         struct btrfs_disk_key *disk_key;
 931                         u8 type;
 932                         u32 item_offset;
 933                         u32 item_size;
 934
 935                         if (disk_item_offset + sizeof(struct btrfs_item) >
 936                             sf->block_ctx->len) {
 937 leaf_item_out_of_bounce_error:
 938                                 pr_info(
 939                 "btrfsic: leaf item out of bounce at logical %llu, dev %pg\n",
 940                                        sf->block_ctx->start,
 941                                        sf->block_ctx->dev->bdev);
 942                                 goto one_stack_frame_backwards;
 943                         }
 944                         btrfsic_read_from_block_data(sf->block_ctx,
 945                                                      &disk_item,
 946                                                      disk_item_offset,
 947                                                      sizeof(struct btrfs_item));
 948                         item_offset = btrfs_stack_item_offset(&disk_item);
 949                         item_size = btrfs_stack_item_size(&disk_item);
 950                         disk_key = &disk_item.key;
 951                         type = btrfs_disk_key_type(disk_key);
 952
 953                         if (BTRFS_ROOT_ITEM_KEY == type) {
 954                                 struct btrfs_root_item root_item;
 955                                 u32 root_item_offset;
 956                                 u64 next_bytenr;
 957
 958                                 root_item_offset = item_offset +
 959                                         offsetof(struct btrfs_leaf, items);
 960                                 if (root_item_offset + item_size >
 961                                     sf->block_ctx->len)
 962                                         goto leaf_item_out_of_bounce_error;
 963                                 btrfsic_read_from_block_data(
 964                                         sf->block_ctx, &root_item,
 965                                         root_item_offset,
 966                                         item_size);
 967                                 next_bytenr = btrfs_root_bytenr(&root_item);
 968
 969                                 sf->error =
 970                                     btrfsic_create_link_to_next_block(
 971                                                 state,
 972                                                 sf->block,
 973                                                 sf->block_ctx,
 974                                                 next_bytenr,
 975                                                 sf->limit_nesting,
 976                                                 &sf->next_block_ctx,
 977                                                 &sf->next_block,
 978                                                 force_iodone_flag,
 979                                                 &sf->num_copies,
 980                                                 &sf->mirror_num,
 981                                                 disk_key,
 982                                                 btrfs_root_generation(
 983                                                 &root_item));
 984                                 if (sf->error)
 985                                         goto one_stack_frame_backwards;
 986
 987                                 if (NULL != sf->next_block) {
 988                                         struct btrfs_header *const next_hdr =
 989                                             (struct btrfs_header *)
 990                                             sf->next_block_ctx.datav[0];
 991
 992                                         next_stack =
 993                                             btrfsic_stack_frame_alloc();
 994                                         if (NULL == next_stack) {
 995                                                 sf->error = -1;
 996                                                 btrfsic_release_block_ctx(
 997                                                                 &sf->
 998                                                                 next_block_ctx);
 999                                                 goto one_stack_frame_backwards;
1000                                         }
1001
1002                                         next_stack->i = -1;
1003                                         next_stack->block = sf->next_block;
1004                                         next_stack->block_ctx =
1005                                             &sf->next_block_ctx;
1006                                         next_stack->next_block = NULL;
1007                                         next_stack->hdr = next_hdr;
1008                                         next_stack->limit_nesting =
1009                                             sf->limit_nesting - 1;
1010                                         next_stack->prev = sf;
1011                                         sf = next_stack;
1012                                         goto continue_with_new_stack_frame;
1013                                 }
1014                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1015                                    state->include_extent_data) {
1016                                 sf->error = btrfsic_handle_extent_data(
1017                                                 state,
1018                                                 sf->block,
1019                                                 sf->block_ctx,
1020                                                 item_offset,
1021                                                 force_iodone_flag);
1022                                 if (sf->error)
1023                                         goto one_stack_frame_backwards;
1024                         }
1025
1026                         goto continue_with_current_leaf_stack_frame;
1027                 }
1028         } else {
1029                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1030
1031                 if (-1 == sf->i) {
1032                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1033
1034                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1035                                 pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1036                                        sf->block_ctx->start,
1037                                        nodehdr->header.level, sf->nr,
1038                                        btrfs_stack_header_generation(
1039                                        &nodehdr->header),
1040                                        btrfs_stack_header_owner(
1041                                        &nodehdr->header));
1042                 }
1043
1044 continue_with_current_node_stack_frame:
1045                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1046                         sf->i++;
1047                         sf->num_copies = 0;
1048                 }
1049
1050                 if (sf->i < sf->nr) {
1051                         struct btrfs_key_ptr key_ptr;
1052                         u32 key_ptr_offset;
1053                         u64 next_bytenr;
1054
1055                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1056                                           (uintptr_t)nodehdr;
1057                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1058                             sf->block_ctx->len) {
1059                                 pr_info(
1060                 "btrfsic: node item out of bounce at logical %llu, dev %pg\n",
1061                                        sf->block_ctx->start,
1062                                        sf->block_ctx->dev->bdev);
1063                                 goto one_stack_frame_backwards;
1064                         }
1065                         btrfsic_read_from_block_data(
1066                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1067                                 sizeof(struct btrfs_key_ptr));
1068                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1069
1070                         sf->error = btrfsic_create_link_to_next_block(
1071                                         state,
1072                                         sf->block,
1073                                         sf->block_ctx,
1074                                         next_bytenr,
1075                                         sf->limit_nesting,
1076                                         &sf->next_block_ctx,
1077                                         &sf->next_block,
1078                                         force_iodone_flag,
1079                                         &sf->num_copies,
1080                                         &sf->mirror_num,
1081                                         &key_ptr.key,
1082                                         btrfs_stack_key_generation(&key_ptr));
1083                         if (sf->error)
1084                                 goto one_stack_frame_backwards;
1085
1086                         if (NULL != sf->next_block) {
1087                                 struct btrfs_header *const next_hdr =
1088                                     (struct btrfs_header *)
1089                                     sf->next_block_ctx.datav[0];
1090
1091                                 next_stack = btrfsic_stack_frame_alloc();
1092                                 if (NULL == next_stack) {
1093                                         sf->error = -1;
1094                                         goto one_stack_frame_backwards;
1095                                 }
1096
1097                                 next_stack->i = -1;
1098                                 next_stack->block = sf->next_block;
1099                                 next_stack->block_ctx = &sf->next_block_ctx;
1100                                 next_stack->next_block = NULL;
1101                                 next_stack->hdr = next_hdr;
1102                                 next_stack->limit_nesting =
1103                                     sf->limit_nesting - 1;
1104                                 next_stack->prev = sf;
1105                                 sf = next_stack;
1106                                 goto continue_with_new_stack_frame;
1107                         }
1108
1109                         goto continue_with_current_node_stack_frame;
1110                 }
1111         }
1112
1113 one_stack_frame_backwards:
1114         if (NULL != sf->prev) {
1115                 struct btrfsic_stack_frame *const prev = sf->prev;
1116
1117                 /* the one for the initial block is freed in the caller */
1118                 btrfsic_release_block_ctx(sf->block_ctx);
1119
1120                 if (sf->error) {
1121                         prev->error = sf->error;
1122                         btrfsic_stack_frame_free(sf);
1123                         sf = prev;
1124                         goto one_stack_frame_backwards;
1125                 }
1126
1127                 btrfsic_stack_frame_free(sf);
1128                 sf = prev;
1129                 goto continue_with_new_stack_frame;
1130         } else {
1131                 BUG_ON(&initial_stack_frame != sf);
1132         }
1133
1134         return sf->error;
1135 }
1136
1137 static void btrfsic_read_from_block_data(
1138         struct btrfsic_block_data_ctx *block_ctx,
1139         void *dstv, u32 offset, size_t len)
1140 {
1141         size_t cur;
1142         size_t pgoff;
1143         char *kaddr;
1144         char *dst = (char *)dstv;
1145         size_t start_offset = offset_in_page(block_ctx->start);
1146         unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1147
1148         WARN_ON(offset + len > block_ctx->len);
1149         pgoff = offset_in_page(start_offset + offset);
1150
1151         while (len > 0) {
1152                 cur = min(len, ((size_t)PAGE_SIZE - pgoff));
1153                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1154                 kaddr = block_ctx->datav[i];
1155                 memcpy(dst, kaddr + pgoff, cur);
1156
1157                 dst += cur;
1158                 len -= cur;
1159                 pgoff = 0;
1160                 i++;
1161         }
1162 }
1163
1164 static int btrfsic_create_link_to_next_block(
1165                 struct btrfsic_state *state,
1166                 struct btrfsic_block *block,
1167                 struct btrfsic_block_data_ctx *block_ctx,
1168                 u64 next_bytenr,
1169                 int limit_nesting,
1170                 struct btrfsic_block_data_ctx *next_block_ctx,
1171                 struct btrfsic_block **next_blockp,
1172                 int force_iodone_flag,
1173                 int *num_copiesp, int *mirror_nump,
1174                 struct btrfs_disk_key *disk_key,
1175                 u64 parent_generation)
1176 {
1177         struct btrfs_fs_info *fs_info = state->fs_info;
1178         struct btrfsic_block *next_block = NULL;
1179         int ret;
1180         struct btrfsic_block_link *l;
1181         int did_alloc_block_link;
1182         int block_was_created;
1183
1184         *next_blockp = NULL;
1185         if (0 == *num_copiesp) {
1186                 *num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
1187                                                 state->metablock_size);
1188                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1189                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1190                                next_bytenr, *num_copiesp);
1191                 *mirror_nump = 1;
1192         }
1193
1194         if (*mirror_nump > *num_copiesp)
1195                 return 0;
1196
1197         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1198                 pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1199                        *mirror_nump);
1200         ret = btrfsic_map_block(state, next_bytenr,
1201                                 state->metablock_size,
1202                                 next_block_ctx, *mirror_nump);
1203         if (ret) {
1204                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1205                        next_bytenr, *mirror_nump);
1206                 btrfsic_release_block_ctx(next_block_ctx);
1207                 *next_blockp = NULL;
1208                 return -1;
1209         }
1210
1211         next_block = btrfsic_block_lookup_or_add(state,
1212                                                  next_block_ctx, "referenced ",
1213                                                  1, force_iodone_flag,
1214                                                  !force_iodone_flag,
1215                                                  *mirror_nump,
1216                                                  &block_was_created);
1217         if (NULL == next_block) {
1218                 btrfsic_release_block_ctx(next_block_ctx);
1219                 *next_blockp = NULL;
1220                 return -1;
1221         }
1222         if (block_was_created) {
1223                 l = NULL;
1224                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1225         } else {
1226                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1227                         if (next_block->logical_bytenr != next_bytenr &&
1228                             !(!next_block->is_metadata &&
1229                               0 == next_block->logical_bytenr))
1230                                 pr_info(
1231 "referenced block @%llu (%pg/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu)\n",
1232                                        next_bytenr, next_block_ctx->dev->bdev,
1233                                        next_block_ctx->dev_bytenr, *mirror_nump,
1234                                        btrfsic_get_block_type(state,
1235                                                               next_block),
1236                                        next_block->logical_bytenr);
1237                         else
1238                                 pr_info(
1239                 "referenced block @%llu (%pg/%llu/%d) found in hash table, %c\n",
1240                                        next_bytenr, next_block_ctx->dev->bdev,
1241                                        next_block_ctx->dev_bytenr, *mirror_nump,
1242                                        btrfsic_get_block_type(state,
1243                                                               next_block));
1244                 }
1245                 next_block->logical_bytenr = next_bytenr;
1246
1247                 next_block->mirror_num = *mirror_nump;
1248                 l = btrfsic_block_link_hashtable_lookup(
1249                                 next_block_ctx->dev->bdev,
1250                                 next_block_ctx->dev_bytenr,
1251                                 block_ctx->dev->bdev,
1252                                 block_ctx->dev_bytenr,
1253                                 &state->block_link_hashtable);
1254         }
1255
1256         next_block->disk_key = *disk_key;
1257         if (NULL == l) {
1258                 l = btrfsic_block_link_alloc();
1259                 if (NULL == l) {
1260                         btrfsic_release_block_ctx(next_block_ctx);
1261                         *next_blockp = NULL;
1262                         return -1;
1263                 }
1264
1265                 did_alloc_block_link = 1;
1266                 l->block_ref_to = next_block;
1267                 l->block_ref_from = block;
1268                 l->ref_cnt = 1;
1269                 l->parent_generation = parent_generation;
1270
1271                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1272                         btrfsic_print_add_link(state, l);
1273
1274                 list_add(&l->node_ref_to, &block->ref_to_list);
1275                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1276
1277                 btrfsic_block_link_hashtable_add(l,
1278                                                  &state->block_link_hashtable);
1279         } else {
1280                 did_alloc_block_link = 0;
1281                 if (0 == limit_nesting) {
1282                         l->ref_cnt++;
1283                         l->parent_generation = parent_generation;
1284                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1285                                 btrfsic_print_add_link(state, l);
1286                 }
1287         }
1288
1289         if (limit_nesting > 0 && did_alloc_block_link) {
1290                 ret = btrfsic_read_block(state, next_block_ctx);
1291                 if (ret < (int)next_block_ctx->len) {
1292                         pr_info("btrfsic: read block @logical %llu failed!\n",
1293                                next_bytenr);
1294                         btrfsic_release_block_ctx(next_block_ctx);
1295                         *next_blockp = NULL;
1296                         return -1;
1297                 }
1298
1299                 *next_blockp = next_block;
1300         } else {
1301                 *next_blockp = NULL;
1302         }
1303         (*mirror_nump)++;
1304
1305         return 0;
1306 }
1307
1308 static int btrfsic_handle_extent_data(
1309                 struct btrfsic_state *state,
1310                 struct btrfsic_block *block,
1311                 struct btrfsic_block_data_ctx *block_ctx,
1312                 u32 item_offset, int force_iodone_flag)
1313 {
1314         struct btrfs_fs_info *fs_info = state->fs_info;
1315         struct btrfs_file_extent_item file_extent_item;
1316         u64 file_extent_item_offset;
1317         u64 next_bytenr;
1318         u64 num_bytes;
1319         u64 generation;
1320         struct btrfsic_block_link *l;
1321         int ret;
1322
1323         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1324                                   item_offset;
1325         if (file_extent_item_offset +
1326             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1327             block_ctx->len) {
1328                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %pg\n",
1329                        block_ctx->start, block_ctx->dev->bdev);
1330                 return -1;
1331         }
1332
1333         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1334                 file_extent_item_offset,
1335                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1336         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1337             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1338                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1339                         pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1340                                file_extent_item.type,
1341                                btrfs_stack_file_extent_disk_bytenr(
1342                                &file_extent_item));
1343                 return 0;
1344         }
1345
1346         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1347             block_ctx->len) {
1348                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %pg\n",
1349                        block_ctx->start, block_ctx->dev->bdev);
1350                 return -1;
1351         }
1352         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1353                                      file_extent_item_offset,
1354                                      sizeof(struct btrfs_file_extent_item));
1355         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1356         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1357             BTRFS_COMPRESS_NONE) {
1358                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1359                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1360         } else {
1361                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1362         }
1363         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1364
1365         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1366                 pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1367                        file_extent_item.type,
1368                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1369                        btrfs_stack_file_extent_offset(&file_extent_item),
1370                        num_bytes);
1371         while (num_bytes > 0) {
1372                 u32 chunk_len;
1373                 int num_copies;
1374                 int mirror_num;
1375
1376                 if (num_bytes > state->datablock_size)
1377                         chunk_len = state->datablock_size;
1378                 else
1379                         chunk_len = num_bytes;
1380
1381                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
1382                                               state->datablock_size);
1383                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1384                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1385                                next_bytenr, num_copies);
1386                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1387                         struct btrfsic_block_data_ctx next_block_ctx;
1388                         struct btrfsic_block *next_block;
1389                         int block_was_created;
1390
1391                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1392                                 pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1393                                         mirror_num);
1394                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1395                                 pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1396                                        next_bytenr, chunk_len);
1397                         ret = btrfsic_map_block(state, next_bytenr,
1398                                                 chunk_len, &next_block_ctx,
1399                                                 mirror_num);
1400                         if (ret) {
1401                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1402                                        next_bytenr, mirror_num);
1403                                 return -1;
1404                         }
1405
1406                         next_block = btrfsic_block_lookup_or_add(
1407                                         state,
1408                                         &next_block_ctx,
1409                                         "referenced ",
1410                                         0,
1411                                         force_iodone_flag,
1412                                         !force_iodone_flag,
1413                                         mirror_num,
1414                                         &block_was_created);
1415                         if (NULL == next_block) {
1416                                 btrfsic_release_block_ctx(&next_block_ctx);
1417                                 return -1;
1418                         }
1419                         if (!block_was_created) {
1420                                 if ((state->print_mask &
1421                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1422                                     next_block->logical_bytenr != next_bytenr &&
1423                                     !(!next_block->is_metadata &&
1424                                       0 == next_block->logical_bytenr)) {
1425                                         pr_info(
1426 "referenced block @%llu (%pg/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu)\n",
1427                                                next_bytenr,
1428                                                next_block_ctx.dev->bdev,
1429                                                next_block_ctx.dev_bytenr,
1430                                                mirror_num,
1431                                                next_block->logical_bytenr);
1432                                 }
1433                                 next_block->logical_bytenr = next_bytenr;
1434                                 next_block->mirror_num = mirror_num;
1435                         }
1436
1437                         l = btrfsic_block_link_lookup_or_add(state,
1438                                                              &next_block_ctx,
1439                                                              next_block, block,
1440                                                              generation);
1441                         btrfsic_release_block_ctx(&next_block_ctx);
1442                         if (NULL == l)
1443                                 return -1;
1444                 }
1445
1446                 next_bytenr += chunk_len;
1447                 num_bytes -= chunk_len;
1448         }
1449
1450         return 0;
1451 }
1452
1453 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1454                              struct btrfsic_block_data_ctx *block_ctx_out,
1455                              int mirror_num)
1456 {
1457         struct btrfs_fs_info *fs_info = state->fs_info;
1458         int ret;
1459         u64 length;
1460         struct btrfs_io_context *multi = NULL;
1461         struct btrfs_device *device;
1462
1463         length = len;
1464         ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
1465                               bytenr, &length, &multi, mirror_num);
1466
1467         if (ret) {
1468                 block_ctx_out->start = 0;
1469                 block_ctx_out->dev_bytenr = 0;
1470                 block_ctx_out->len = 0;
1471                 block_ctx_out->dev = NULL;
1472                 block_ctx_out->datav = NULL;
1473                 block_ctx_out->pagev = NULL;
1474                 block_ctx_out->mem_to_free = NULL;
1475
1476                 return ret;
1477         }
1478
1479         device = multi->stripes[0].dev;
1480         if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) ||
1481             !device->bdev || !device->name)
1482                 block_ctx_out->dev = NULL;
1483         else
1484                 block_ctx_out->dev = btrfsic_dev_state_lookup(
1485                                                         device->bdev->bd_dev);
1486         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1487         block_ctx_out->start = bytenr;
1488         block_ctx_out->len = len;
1489         block_ctx_out->datav = NULL;
1490         block_ctx_out->pagev = NULL;
1491         block_ctx_out->mem_to_free = NULL;
1492
1493         kfree(multi);
1494         if (NULL == block_ctx_out->dev) {
1495                 ret = -ENXIO;
1496                 pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1497         }
1498
1499         return ret;
1500 }
1501
1502 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1503 {
1504         if (block_ctx->mem_to_free) {
1505                 unsigned int num_pages;
1506
1507                 BUG_ON(!block_ctx->datav);
1508                 BUG_ON(!block_ctx->pagev);
1509                 num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1510                             PAGE_SHIFT;
1511                 /* Pages must be unmapped in reverse order */
1512                 while (num_pages > 0) {
1513                         num_pages--;
1514                         if (block_ctx->datav[num_pages])
1515                                 block_ctx->datav[num_pages] = NULL;
1516                         if (block_ctx->pagev[num_pages]) {
1517                                 __free_page(block_ctx->pagev[num_pages]);
1518                                 block_ctx->pagev[num_pages] = NULL;
1519                         }
1520                 }
1521
1522                 kfree(block_ctx->mem_to_free);
1523                 block_ctx->mem_to_free = NULL;
1524                 block_ctx->pagev = NULL;
1525                 block_ctx->datav = NULL;
1526         }
1527 }
1528
1529 static int btrfsic_read_block(struct btrfsic_state *state,
1530                               struct btrfsic_block_data_ctx *block_ctx)
1531 {
1532         unsigned int num_pages;
1533         unsigned int i;
1534         size_t size;
1535         u64 dev_bytenr;
1536         int ret;
1537
1538         BUG_ON(block_ctx->datav);
1539         BUG_ON(block_ctx->pagev);
1540         BUG_ON(block_ctx->mem_to_free);
1541         if (!PAGE_ALIGNED(block_ctx->dev_bytenr)) {
1542                 pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1543                        block_ctx->dev_bytenr);
1544                 return -1;
1545         }
1546
1547         num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1548                     PAGE_SHIFT;
1549         size = sizeof(*block_ctx->datav) + sizeof(*block_ctx->pagev);
1550         block_ctx->mem_to_free = kcalloc(num_pages, size, GFP_NOFS);
1551         if (!block_ctx->mem_to_free)
1552                 return -ENOMEM;
1553         block_ctx->datav = block_ctx->mem_to_free;
1554         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1555         for (i = 0; i < num_pages; i++) {
1556                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1557                 if (!block_ctx->pagev[i])
1558                         return -1;
1559         }
1560
1561         dev_bytenr = block_ctx->dev_bytenr;
1562         for (i = 0; i < num_pages;) {
1563                 struct bio *bio;
1564                 unsigned int j;
1565
1566                 bio = btrfs_bio_alloc(num_pages - i);
1567                 bio_set_dev(bio, block_ctx->dev->bdev);
1568                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1569                 bio->bi_opf = REQ_OP_READ;
1570
1571                 for (j = i; j < num_pages; j++) {
1572                         ret = bio_add_page(bio, block_ctx->pagev[j],
1573                                            PAGE_SIZE, 0);
1574                         if (PAGE_SIZE != ret)
1575                                 break;
1576                 }
1577                 if (j == i) {
1578                         pr_info("btrfsic: error, failed to add a single page!\n");
1579                         return -1;
1580                 }
1581                 if (submit_bio_wait(bio)) {
1582                         pr_info("btrfsic: read error at logical %llu dev %pg!\n",
1583                                block_ctx->start, block_ctx->dev->bdev);
1584                         bio_put(bio);
1585                         return -1;
1586                 }
1587                 bio_put(bio);
1588                 dev_bytenr += (j - i) * PAGE_SIZE;
1589                 i = j;
1590         }
1591         for (i = 0; i < num_pages; i++)
1592                 block_ctx->datav[i] = page_address(block_ctx->pagev[i]);
1593
1594         return block_ctx->len;
1595 }
1596
1597 static void btrfsic_dump_database(struct btrfsic_state *state)
1598 {
1599         const struct btrfsic_block *b_all;
1600
1601         BUG_ON(NULL == state);
1602
1603         pr_info("all_blocks_list:\n");
1604         list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1605                 const struct btrfsic_block_link *l;
1606
1607                 pr_info("%c-block @%llu (%pg/%llu/%d)\n",
1608                        btrfsic_get_block_type(state, b_all),
1609                        b_all->logical_bytenr, b_all->dev_state->bdev,
1610                        b_all->dev_bytenr, b_all->mirror_num);
1611
1612                 list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1613                         pr_info(
1614                 " %c @%llu (%pg/%llu/%d) refers %u* to %c @%llu (%pg/%llu/%d)\n",
1615                                btrfsic_get_block_type(state, b_all),
1616                                b_all->logical_bytenr, b_all->dev_state->bdev,
1617                                b_all->dev_bytenr, b_all->mirror_num,
1618                                l->ref_cnt,
1619                                btrfsic_get_block_type(state, l->block_ref_to),
1620                                l->block_ref_to->logical_bytenr,
1621                                l->block_ref_to->dev_state->bdev,
1622                                l->block_ref_to->dev_bytenr,
1623                                l->block_ref_to->mirror_num);
1624                 }
1625
1626                 list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1627                         pr_info(
1628                 " %c @%llu (%pg/%llu/%d) is ref %u* from %c @%llu (%pg/%llu/%d)\n",
1629                                btrfsic_get_block_type(state, b_all),
1630                                b_all->logical_bytenr, b_all->dev_state->bdev,
1631                                b_all->dev_bytenr, b_all->mirror_num,
1632                                l->ref_cnt,
1633                                btrfsic_get_block_type(state, l->block_ref_from),
1634                                l->block_ref_from->logical_bytenr,
1635                                l->block_ref_from->dev_state->bdev,
1636                                l->block_ref_from->dev_bytenr,
1637                                l->block_ref_from->mirror_num);
1638                 }
1639
1640                 pr_info("\n");
1641         }
1642 }
1643
1644 /*
1645  * Test whether the disk block contains a tree block (leaf or node)
1646  * (note that this test fails for the super block)
1647  */
1648 static noinline_for_stack int btrfsic_test_for_metadata(
1649                 struct btrfsic_state *state,
1650                 char **datav, unsigned int num_pages)
1651 {
1652         struct btrfs_fs_info *fs_info = state->fs_info;
1653         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
1654         struct btrfs_header *h;
1655         u8 csum[BTRFS_CSUM_SIZE];
1656         unsigned int i;
1657
1658         if (num_pages * PAGE_SIZE < state->metablock_size)
1659                 return 1; /* not metadata */
1660         num_pages = state->metablock_size >> PAGE_SHIFT;
1661         h = (struct btrfs_header *)datav[0];
1662
1663         if (memcmp(h->fsid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE))
1664                 return 1;
1665
1666         shash->tfm = fs_info->csum_shash;
1667         crypto_shash_init(shash);
1668
1669         for (i = 0; i < num_pages; i++) {
1670                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1671                 size_t sublen = i ? PAGE_SIZE :
1672                                     (PAGE_SIZE - BTRFS_CSUM_SIZE);
1673
1674                 crypto_shash_update(shash, data, sublen);
1675         }
1676         crypto_shash_final(shash, csum);
1677         if (memcmp(csum, h->csum, fs_info->csum_size))
1678                 return 1;
1679
1680         return 0; /* is metadata */
1681 }
1682
1683 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1684                                           u64 dev_bytenr, char **mapped_datav,
1685                                           unsigned int num_pages,
1686                                           struct bio *bio, int *bio_is_patched,
1687                                           int submit_bio_bh_rw)
1688 {
1689         int is_metadata;
1690         struct btrfsic_block *block;
1691         struct btrfsic_block_data_ctx block_ctx;
1692         int ret;
1693         struct btrfsic_state *state = dev_state->state;
1694         struct block_device *bdev = dev_state->bdev;
1695         unsigned int processed_len;
1696
1697         if (NULL != bio_is_patched)
1698                 *bio_is_patched = 0;
1699
1700 again:
1701         if (num_pages == 0)
1702                 return;
1703
1704         processed_len = 0;
1705         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1706                                                       num_pages));
1707
1708         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1709                                                &state->block_hashtable);
1710         if (NULL != block) {
1711                 u64 bytenr = 0;
1712                 struct btrfsic_block_link *l, *tmp;
1713
1714                 if (block->is_superblock) {
1715                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1716                                                     mapped_datav[0]);
1717                         if (num_pages * PAGE_SIZE <
1718                             BTRFS_SUPER_INFO_SIZE) {
1719                                 pr_info("btrfsic: cannot work with too short bios!\n");
1720                                 return;
1721                         }
1722                         is_metadata = 1;
1723                         BUG_ON(!PAGE_ALIGNED(BTRFS_SUPER_INFO_SIZE));
1724                         processed_len = BTRFS_SUPER_INFO_SIZE;
1725                         if (state->print_mask &
1726                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1727                                 pr_info("[before new superblock is written]:\n");
1728                                 btrfsic_dump_tree_sub(state, block, 0);
1729                         }
1730                 }
1731                 if (is_metadata) {
1732                         if (!block->is_superblock) {
1733                                 if (num_pages * PAGE_SIZE <
1734                                     state->metablock_size) {
1735                                         pr_info("btrfsic: cannot work with too short bios!\n");
1736                                         return;
1737                                 }
1738                                 processed_len = state->metablock_size;
1739                                 bytenr = btrfs_stack_header_bytenr(
1740                                                 (struct btrfs_header *)
1741                                                 mapped_datav[0]);
1742                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1743                                                                dev_state,
1744                                                                dev_bytenr);
1745                         }
1746                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1747                                 if (block->logical_bytenr != bytenr &&
1748                                     !(!block->is_metadata &&
1749                                       block->logical_bytenr == 0))
1750                                         pr_info(
1751 "written block @%llu (%pg/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu)\n",
1752                                                bytenr, dev_state->bdev,
1753                                                dev_bytenr,
1754                                                block->mirror_num,
1755                                                btrfsic_get_block_type(state,
1756                                                                       block),
1757                                                block->logical_bytenr);
1758                                 else
1759                                         pr_info(
1760                 "written block @%llu (%pg/%llu/%d) found in hash table, %c\n",
1761                                                bytenr, dev_state->bdev,
1762                                                dev_bytenr, block->mirror_num,
1763                                                btrfsic_get_block_type(state,
1764                                                                       block));
1765                         }
1766                         block->logical_bytenr = bytenr;
1767                 } else {
1768                         if (num_pages * PAGE_SIZE <
1769                             state->datablock_size) {
1770                                 pr_info("btrfsic: cannot work with too short bios!\n");
1771                                 return;
1772                         }
1773                         processed_len = state->datablock_size;
1774                         bytenr = block->logical_bytenr;
1775                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1776                                 pr_info(
1777                 "written block @%llu (%pg/%llu/%d) found in hash table, %c\n",
1778                                        bytenr, dev_state->bdev, dev_bytenr,
1779                                        block->mirror_num,
1780                                        btrfsic_get_block_type(state, block));
1781                 }
1782
1783                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1784                         pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1785                                list_empty(&block->ref_to_list) ? ' ' : '!',
1786                                list_empty(&block->ref_from_list) ? ' ' : '!');
1787                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1788                         pr_info(
1789 "btrfs: attempt to overwrite %c-block @%llu (%pg/%llu/%d), old(gen=%llu, objectid=%llu, type=%d, offset=%llu), new(gen=%llu), which is referenced by most recent superblock (superblockgen=%llu)!\n",
1790                                btrfsic_get_block_type(state, block), bytenr,
1791                                dev_state->bdev, dev_bytenr, block->mirror_num,
1792                                block->generation,
1793                                btrfs_disk_key_objectid(&block->disk_key),
1794                                block->disk_key.type,
1795                                btrfs_disk_key_offset(&block->disk_key),
1796                                btrfs_stack_header_generation(
1797                                        (struct btrfs_header *) mapped_datav[0]),
1798                                state->max_superblock_generation);
1799                         btrfsic_dump_tree(state);
1800                 }
1801
1802                 if (!block->is_iodone && !block->never_written) {
1803                         pr_info(
1804 "btrfs: attempt to overwrite %c-block @%llu (%pg/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1805                                btrfsic_get_block_type(state, block), bytenr,
1806                                dev_state->bdev, dev_bytenr, block->mirror_num,
1807                                block->generation,
1808                                btrfs_stack_header_generation(
1809                                        (struct btrfs_header *)
1810                                        mapped_datav[0]));
1811                         /* it would not be safe to go on */
1812                         btrfsic_dump_tree(state);
1813                         goto continue_loop;
1814                 }
1815
1816                 /*
1817                  * Clear all references of this block. Do not free
1818                  * the block itself even if is not referenced anymore
1819                  * because it still carries valuable information
1820                  * like whether it was ever written and IO completed.
1821                  */
1822                 list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1823                                          node_ref_to) {
1824                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1825                                 btrfsic_print_rem_link(state, l);
1826                         l->ref_cnt--;
1827                         if (0 == l->ref_cnt) {
1828                                 list_del(&l->node_ref_to);
1829                                 list_del(&l->node_ref_from);
1830                                 btrfsic_block_link_hashtable_remove(l);
1831                                 btrfsic_block_link_free(l);
1832                         }
1833                 }
1834
1835                 block_ctx.dev = dev_state;
1836                 block_ctx.dev_bytenr = dev_bytenr;
1837                 block_ctx.start = bytenr;
1838                 block_ctx.len = processed_len;
1839                 block_ctx.pagev = NULL;
1840                 block_ctx.mem_to_free = NULL;
1841                 block_ctx.datav = mapped_datav;
1842
1843                 if (is_metadata || state->include_extent_data) {
1844                         block->never_written = 0;
1845                         block->iodone_w_error = 0;
1846                         if (NULL != bio) {
1847                                 block->is_iodone = 0;
1848                                 BUG_ON(NULL == bio_is_patched);
1849                                 if (!*bio_is_patched) {
1850                                         block->orig_bio_private =
1851                                             bio->bi_private;
1852                                         block->orig_bio_end_io =
1853                                             bio->bi_end_io;
1854                                         block->next_in_same_bio = NULL;
1855                                         bio->bi_private = block;
1856                                         bio->bi_end_io = btrfsic_bio_end_io;
1857                                         *bio_is_patched = 1;
1858                                 } else {
1859                                         struct btrfsic_block *chained_block =
1860                                             (struct btrfsic_block *)
1861                                             bio->bi_private;
1862
1863                                         BUG_ON(NULL == chained_block);
1864                                         block->orig_bio_private =
1865                                             chained_block->orig_bio_private;
1866                                         block->orig_bio_end_io =
1867                                             chained_block->orig_bio_end_io;
1868                                         block->next_in_same_bio = chained_block;
1869                                         bio->bi_private = block;
1870                                 }
1871                         } else {
1872                                 block->is_iodone = 1;
1873                                 block->orig_bio_private = NULL;
1874                                 block->orig_bio_end_io = NULL;
1875                                 block->next_in_same_bio = NULL;
1876                         }
1877                 }
1878
1879                 block->flush_gen = dev_state->last_flush_gen + 1;
1880                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1881                 if (is_metadata) {
1882                         block->logical_bytenr = bytenr;
1883                         block->is_metadata = 1;
1884                         if (block->is_superblock) {
1885                                 BUG_ON(PAGE_SIZE !=
1886                                        BTRFS_SUPER_INFO_SIZE);
1887                                 ret = btrfsic_process_written_superblock(
1888                                                 state,
1889                                                 block,
1890                                                 (struct btrfs_super_block *)
1891                                                 mapped_datav[0]);
1892                                 if (state->print_mask &
1893                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1894                                         pr_info("[after new superblock is written]:\n");
1895                                         btrfsic_dump_tree_sub(state, block, 0);
1896                                 }
1897                         } else {
1898                                 block->mirror_num = 0;  /* unknown */
1899                                 ret = btrfsic_process_metablock(
1900                                                 state,
1901                                                 block,
1902                                                 &block_ctx,
1903                                                 0, 0);
1904                         }
1905                         if (ret)
1906                                 pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1907                                        dev_bytenr);
1908                 } else {
1909                         block->is_metadata = 0;
1910                         block->mirror_num = 0;  /* unknown */
1911                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
1912                         if (!state->include_extent_data
1913                             && list_empty(&block->ref_from_list)) {
1914                                 /*
1915                                  * disk block is overwritten with extent
1916                                  * data (not meta data) and we are configured
1917                                  * to not include extent data: take the
1918                                  * chance and free the block's memory
1919                                  */
1920                                 btrfsic_block_hashtable_remove(block);
1921                                 list_del(&block->all_blocks_node);
1922                                 btrfsic_block_free(block);
1923                         }
1924                 }
1925                 btrfsic_release_block_ctx(&block_ctx);
1926         } else {
1927                 /* block has not been found in hash table */
1928                 u64 bytenr;
1929
1930                 if (!is_metadata) {
1931                         processed_len = state->datablock_size;
1932                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1933                                 pr_info(
1934                         "written block (%pg/%llu/?) !found in hash table, D\n",
1935                                        dev_state->bdev, dev_bytenr);
1936                         if (!state->include_extent_data) {
1937                                 /* ignore that written D block */
1938                                 goto continue_loop;
1939                         }
1940
1941                         /* this is getting ugly for the
1942                          * include_extent_data case... */
1943                         bytenr = 0;     /* unknown */
1944                 } else {
1945                         processed_len = state->metablock_size;
1946                         bytenr = btrfs_stack_header_bytenr(
1947                                         (struct btrfs_header *)
1948                                         mapped_datav[0]);
1949                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
1950                                                        dev_bytenr);
1951                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1952                                 pr_info(
1953                         "written block @%llu (%pg/%llu/?) !found in hash table, M\n",
1954                                        bytenr, dev_state->bdev, dev_bytenr);
1955                 }
1956
1957                 block_ctx.dev = dev_state;
1958                 block_ctx.dev_bytenr = dev_bytenr;
1959                 block_ctx.start = bytenr;
1960                 block_ctx.len = processed_len;
1961                 block_ctx.pagev = NULL;
1962                 block_ctx.mem_to_free = NULL;
1963                 block_ctx.datav = mapped_datav;
1964
1965                 block = btrfsic_block_alloc();
1966                 if (NULL == block) {
1967                         btrfsic_release_block_ctx(&block_ctx);
1968                         goto continue_loop;
1969                 }
1970                 block->dev_state = dev_state;
1971                 block->dev_bytenr = dev_bytenr;
1972                 block->logical_bytenr = bytenr;
1973                 block->is_metadata = is_metadata;
1974                 block->never_written = 0;
1975                 block->iodone_w_error = 0;
1976                 block->mirror_num = 0;  /* unknown */
1977                 block->flush_gen = dev_state->last_flush_gen + 1;
1978                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1979                 if (NULL != bio) {
1980                         block->is_iodone = 0;
1981                         BUG_ON(NULL == bio_is_patched);
1982                         if (!*bio_is_patched) {
1983                                 block->orig_bio_private = bio->bi_private;
1984                                 block->orig_bio_end_io = bio->bi_end_io;
1985                                 block->next_in_same_bio = NULL;
1986                                 bio->bi_private = block;
1987                                 bio->bi_end_io = btrfsic_bio_end_io;
1988                                 *bio_is_patched = 1;
1989                         } else {
1990                                 struct btrfsic_block *chained_block =
1991                                     (struct btrfsic_block *)
1992                                     bio->bi_private;
1993
1994                                 BUG_ON(NULL == chained_block);
1995                                 block->orig_bio_private =
1996                                     chained_block->orig_bio_private;
1997                                 block->orig_bio_end_io =
1998                                     chained_block->orig_bio_end_io;
1999                                 block->next_in_same_bio = chained_block;
2000                                 bio->bi_private = block;
2001                         }
2002                 } else {
2003                         block->is_iodone = 1;
2004                         block->orig_bio_private = NULL;
2005                         block->orig_bio_end_io = NULL;
2006                         block->next_in_same_bio = NULL;
2007                 }
2008                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2009                         pr_info("new written %c-block @%llu (%pg/%llu/%d)\n",
2010                                is_metadata ? 'M' : 'D',
2011                                block->logical_bytenr, block->dev_state->bdev,
2012                                block->dev_bytenr, block->mirror_num);
2013                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2014                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2015
2016                 if (is_metadata) {
2017                         ret = btrfsic_process_metablock(state, block,
2018                                                         &block_ctx, 0, 0);
2019                         if (ret)
2020                                 pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2021                                        dev_bytenr);
2022                 }
2023                 btrfsic_release_block_ctx(&block_ctx);
2024         }
2025
2026 continue_loop:
2027         BUG_ON(!processed_len);
2028         dev_bytenr += processed_len;
2029         mapped_datav += processed_len >> PAGE_SHIFT;
2030         num_pages -= processed_len >> PAGE_SHIFT;
2031         goto again;
2032 }
2033
2034 static void btrfsic_bio_end_io(struct bio *bp)
2035 {
2036         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2037         int iodone_w_error;
2038
2039         /* mutex is not held! This is not save if IO is not yet completed
2040          * on umount */
2041         iodone_w_error = 0;
2042         if (bp->bi_status)
2043                 iodone_w_error = 1;
2044
2045         BUG_ON(NULL == block);
2046         bp->bi_private = block->orig_bio_private;
2047         bp->bi_end_io = block->orig_bio_end_io;
2048
2049         do {
2050                 struct btrfsic_block *next_block;
2051                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2052
2053                 if ((dev_state->state->print_mask &
2054                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2055                         pr_info("bio_end_io(err=%d) for %c @%llu (%pg/%llu/%d)\n",
2056                                bp->bi_status,
2057                                btrfsic_get_block_type(dev_state->state, block),
2058                                block->logical_bytenr, dev_state->bdev,
2059                                block->dev_bytenr, block->mirror_num);
2060                 next_block = block->next_in_same_bio;
2061                 block->iodone_w_error = iodone_w_error;
2062                 if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2063                         dev_state->last_flush_gen++;
2064                         if ((dev_state->state->print_mask &
2065                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2066                                 pr_info("bio_end_io() new %pg flush_gen=%llu\n",
2067                                        dev_state->bdev,
2068                                        dev_state->last_flush_gen);
2069                 }
2070                 if (block->submit_bio_bh_rw & REQ_FUA)
2071                         block->flush_gen = 0; /* FUA completed means block is
2072                                                * on disk */
2073                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2074                 block = next_block;
2075         } while (NULL != block);
2076
2077         bp->bi_end_io(bp);
2078 }
2079
2080 static int btrfsic_process_written_superblock(
2081                 struct btrfsic_state *state,
2082                 struct btrfsic_block *const superblock,
2083                 struct btrfs_super_block *const super_hdr)
2084 {
2085         struct btrfs_fs_info *fs_info = state->fs_info;
2086         int pass;
2087
2088         superblock->generation = btrfs_super_generation(super_hdr);
2089         if (!(superblock->generation > state->max_superblock_generation ||
2090               0 == state->max_superblock_generation)) {
2091                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2092                         pr_info(
2093         "btrfsic: superblock @%llu (%pg/%llu/%d) with old gen %llu <= %llu\n",
2094                                superblock->logical_bytenr,
2095                                superblock->dev_state->bdev,
2096                                superblock->dev_bytenr, superblock->mirror_num,
2097                                btrfs_super_generation(super_hdr),
2098                                state->max_superblock_generation);
2099         } else {
2100                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2101                         pr_info(
2102         "btrfsic: got new superblock @%llu (%pg/%llu/%d) with new gen %llu > %llu\n",
2103                                superblock->logical_bytenr,
2104                                superblock->dev_state->bdev,
2105                                superblock->dev_bytenr, superblock->mirror_num,
2106                                btrfs_super_generation(super_hdr),
2107                                state->max_superblock_generation);
2108
2109                 state->max_superblock_generation =
2110                     btrfs_super_generation(super_hdr);
2111                 state->latest_superblock = superblock;
2112         }
2113
2114         for (pass = 0; pass < 3; pass++) {
2115                 int ret;
2116                 u64 next_bytenr;
2117                 struct btrfsic_block *next_block;
2118                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2119                 struct btrfsic_block_link *l;
2120                 int num_copies;
2121                 int mirror_num;
2122                 const char *additional_string = NULL;
2123                 struct btrfs_disk_key tmp_disk_key = {0};
2124
2125                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2126                                             BTRFS_ROOT_ITEM_KEY);
2127                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2128
2129                 switch (pass) {
2130                 case 0:
2131                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2132                                                     BTRFS_ROOT_TREE_OBJECTID);
2133                         additional_string = "root ";
2134                         next_bytenr = btrfs_super_root(super_hdr);
2135                         if (state->print_mask &
2136                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2137                                 pr_info("root@%llu\n", next_bytenr);
2138                         break;
2139                 case 1:
2140                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2141                                                     BTRFS_CHUNK_TREE_OBJECTID);
2142                         additional_string = "chunk ";
2143                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2144                         if (state->print_mask &
2145                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2146                                 pr_info("chunk@%llu\n", next_bytenr);
2147                         break;
2148                 case 2:
2149                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2150                                                     BTRFS_TREE_LOG_OBJECTID);
2151                         additional_string = "log ";
2152                         next_bytenr = btrfs_super_log_root(super_hdr);
2153                         if (0 == next_bytenr)
2154                                 continue;
2155                         if (state->print_mask &
2156                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2157                                 pr_info("log@%llu\n", next_bytenr);
2158                         break;
2159                 }
2160
2161                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
2162                                               BTRFS_SUPER_INFO_SIZE);
2163                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2164                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
2165                                next_bytenr, num_copies);
2166                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2167                         int was_created;
2168
2169                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2170                                 pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2171                         ret = btrfsic_map_block(state, next_bytenr,
2172                                                 BTRFS_SUPER_INFO_SIZE,
2173                                                 &tmp_next_block_ctx,
2174                                                 mirror_num);
2175                         if (ret) {
2176                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2177                                        next_bytenr, mirror_num);
2178                                 return -1;
2179                         }
2180
2181                         next_block = btrfsic_block_lookup_or_add(
2182                                         state,
2183                                         &tmp_next_block_ctx,
2184                                         additional_string,
2185                                         1, 0, 1,
2186                                         mirror_num,
2187                                         &was_created);
2188                         if (NULL == next_block) {
2189                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2190                                 return -1;
2191                         }
2192
2193                         next_block->disk_key = tmp_disk_key;
2194                         if (was_created)
2195                                 next_block->generation =
2196                                     BTRFSIC_GENERATION_UNKNOWN;
2197                         l = btrfsic_block_link_lookup_or_add(
2198                                         state,
2199                                         &tmp_next_block_ctx,
2200                                         next_block,
2201                                         superblock,
2202                                         BTRFSIC_GENERATION_UNKNOWN);
2203                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2204                         if (NULL == l)
2205                                 return -1;
2206                 }
2207         }
2208
2209         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2210                 btrfsic_dump_tree(state);
2211
2212         return 0;
2213 }
2214
2215 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2216                                         struct btrfsic_block *const block,
2217                                         int recursion_level)
2218 {
2219         const struct btrfsic_block_link *l;
2220         int ret = 0;
2221
2222         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2223                 /*
2224                  * Note that this situation can happen and does not
2225                  * indicate an error in regular cases. It happens
2226                  * when disk blocks are freed and later reused.
2227                  * The check-integrity module is not aware of any
2228                  * block free operations, it just recognizes block
2229                  * write operations. Therefore it keeps the linkage
2230                  * information for a block until a block is
2231                  * rewritten. This can temporarily cause incorrect
2232                  * and even circular linkage information. This
2233                  * causes no harm unless such blocks are referenced
2234                  * by the most recent super block.
2235                  */
2236                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2237                         pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2238
2239                 return ret;
2240         }
2241
2242         /*
2243          * This algorithm is recursive because the amount of used stack
2244          * space is very small and the max recursion depth is limited.
2245          */
2246         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2247                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2248                         pr_info(
2249                 "rl=%d, %c @%llu (%pg/%llu/%d) %u* refers to %c @%llu (%pg/%llu/%d)\n",
2250                                recursion_level,
2251                                btrfsic_get_block_type(state, block),
2252                                block->logical_bytenr, block->dev_state->bdev,
2253                                block->dev_bytenr, block->mirror_num,
2254                                l->ref_cnt,
2255                                btrfsic_get_block_type(state, l->block_ref_to),
2256                                l->block_ref_to->logical_bytenr,
2257                                l->block_ref_to->dev_state->bdev,
2258                                l->block_ref_to->dev_bytenr,
2259                                l->block_ref_to->mirror_num);
2260                 if (l->block_ref_to->never_written) {
2261                         pr_info(
2262 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is never written!\n",
2263                                btrfsic_get_block_type(state, l->block_ref_to),
2264                                l->block_ref_to->logical_bytenr,
2265                                l->block_ref_to->dev_state->bdev,
2266                                l->block_ref_to->dev_bytenr,
2267                                l->block_ref_to->mirror_num);
2268                         ret = -1;
2269                 } else if (!l->block_ref_to->is_iodone) {
2270                         pr_info(
2271 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is not yet iodone!\n",
2272                                btrfsic_get_block_type(state, l->block_ref_to),
2273                                l->block_ref_to->logical_bytenr,
2274                                l->block_ref_to->dev_state->bdev,
2275                                l->block_ref_to->dev_bytenr,
2276                                l->block_ref_to->mirror_num);
2277                         ret = -1;
2278                 } else if (l->block_ref_to->iodone_w_error) {
2279                         pr_info(
2280 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which has write error!\n",
2281                                btrfsic_get_block_type(state, l->block_ref_to),
2282                                l->block_ref_to->logical_bytenr,
2283                                l->block_ref_to->dev_state->bdev,
2284                                l->block_ref_to->dev_bytenr,
2285                                l->block_ref_to->mirror_num);
2286                         ret = -1;
2287                 } else if (l->parent_generation !=
2288                            l->block_ref_to->generation &&
2289                            BTRFSIC_GENERATION_UNKNOWN !=
2290                            l->parent_generation &&
2291                            BTRFSIC_GENERATION_UNKNOWN !=
2292                            l->block_ref_to->generation) {
2293                         pr_info(
2294 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) with generation %llu != parent generation %llu!\n",
2295                                btrfsic_get_block_type(state, l->block_ref_to),
2296                                l->block_ref_to->logical_bytenr,
2297                                l->block_ref_to->dev_state->bdev,
2298                                l->block_ref_to->dev_bytenr,
2299                                l->block_ref_to->mirror_num,
2300                                l->block_ref_to->generation,
2301                                l->parent_generation);
2302                         ret = -1;
2303                 } else if (l->block_ref_to->flush_gen >
2304                            l->block_ref_to->dev_state->last_flush_gen) {
2305                         pr_info(
2306 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is not flushed out of disk's write cache (block flush_gen=%llu, dev->flush_gen=%llu)!\n",
2307                                btrfsic_get_block_type(state, l->block_ref_to),
2308                                l->block_ref_to->logical_bytenr,
2309                                l->block_ref_to->dev_state->bdev,
2310                                l->block_ref_to->dev_bytenr,
2311                                l->block_ref_to->mirror_num, block->flush_gen,
2312                                l->block_ref_to->dev_state->last_flush_gen);
2313                         ret = -1;
2314                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2315                                                               l->block_ref_to,
2316                                                               recursion_level +
2317                                                               1)) {
2318                         ret = -1;
2319                 }
2320         }
2321
2322         return ret;
2323 }
2324
2325 static int btrfsic_is_block_ref_by_superblock(
2326                 const struct btrfsic_state *state,
2327                 const struct btrfsic_block *block,
2328                 int recursion_level)
2329 {
2330         const struct btrfsic_block_link *l;
2331
2332         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2333                 /* refer to comment at "abort cyclic linkage (case 1)" */
2334                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2335                         pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2336
2337                 return 0;
2338         }
2339
2340         /*
2341          * This algorithm is recursive because the amount of used stack space
2342          * is very small and the max recursion depth is limited.
2343          */
2344         list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2345                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2346                         pr_info(
2347         "rl=%d, %c @%llu (%pg/%llu/%d) is ref %u* from %c @%llu (%pg/%llu/%d)\n",
2348                                recursion_level,
2349                                btrfsic_get_block_type(state, block),
2350                                block->logical_bytenr, block->dev_state->bdev,
2351                                block->dev_bytenr, block->mirror_num,
2352                                l->ref_cnt,
2353                                btrfsic_get_block_type(state, l->block_ref_from),
2354                                l->block_ref_from->logical_bytenr,
2355                                l->block_ref_from->dev_state->bdev,
2356                                l->block_ref_from->dev_bytenr,
2357                                l->block_ref_from->mirror_num);
2358                 if (l->block_ref_from->is_superblock &&
2359                     state->latest_superblock->dev_bytenr ==
2360                     l->block_ref_from->dev_bytenr &&
2361                     state->latest_superblock->dev_state->bdev ==
2362                     l->block_ref_from->dev_state->bdev)
2363                         return 1;
2364                 else if (btrfsic_is_block_ref_by_superblock(state,
2365                                                             l->block_ref_from,
2366                                                             recursion_level +
2367                                                             1))
2368                         return 1;
2369         }
2370
2371         return 0;
2372 }
2373
2374 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2375                                    const struct btrfsic_block_link *l)
2376 {
2377         pr_info("add %u* link from %c @%llu (%pg/%llu/%d) to %c @%llu (%pg/%llu/%d)\n",
2378                l->ref_cnt,
2379                btrfsic_get_block_type(state, l->block_ref_from),
2380                l->block_ref_from->logical_bytenr,
2381                l->block_ref_from->dev_state->bdev,
2382                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2383                btrfsic_get_block_type(state, l->block_ref_to),
2384                l->block_ref_to->logical_bytenr,
2385                l->block_ref_to->dev_state->bdev, l->block_ref_to->dev_bytenr,
2386                l->block_ref_to->mirror_num);
2387 }
2388
2389 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2390                                    const struct btrfsic_block_link *l)
2391 {
2392         pr_info("rem %u* link from %c @%llu (%pg/%llu/%d) to %c @%llu (%pg/%llu/%d)\n",
2393                l->ref_cnt,
2394                btrfsic_get_block_type(state, l->block_ref_from),
2395                l->block_ref_from->logical_bytenr,
2396                l->block_ref_from->dev_state->bdev,
2397                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2398                btrfsic_get_block_type(state, l->block_ref_to),
2399                l->block_ref_to->logical_bytenr,
2400                l->block_ref_to->dev_state->bdev, l->block_ref_to->dev_bytenr,
2401                l->block_ref_to->mirror_num);
2402 }
2403
2404 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2405                                    const struct btrfsic_block *block)
2406 {
2407         if (block->is_superblock &&
2408             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2409             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2410                 return 'S';
2411         else if (block->is_superblock)
2412                 return 's';
2413         else if (block->is_metadata)
2414                 return 'M';
2415         else
2416                 return 'D';
2417 }
2418
2419 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2420 {
2421         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2422 }
2423
2424 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2425                                   const struct btrfsic_block *block,
2426                                   int indent_level)
2427 {
2428         const struct btrfsic_block_link *l;
2429         int indent_add;
2430         static char buf[80];
2431         int cursor_position;
2432
2433         /*
2434          * Should better fill an on-stack buffer with a complete line and
2435          * dump it at once when it is time to print a newline character.
2436          */
2437
2438         /*
2439          * This algorithm is recursive because the amount of used stack space
2440          * is very small and the max recursion depth is limited.
2441          */
2442         indent_add = sprintf(buf, "%c-%llu(%pg/%llu/%u)",
2443                              btrfsic_get_block_type(state, block),
2444                              block->logical_bytenr, block->dev_state->bdev,
2445                              block->dev_bytenr, block->mirror_num);
2446         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2447                 printk("[...]\n");
2448                 return;
2449         }
2450         printk(buf);
2451         indent_level += indent_add;
2452         if (list_empty(&block->ref_to_list)) {
2453                 printk("\n");
2454                 return;
2455         }
2456         if (block->mirror_num > 1 &&
2457             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2458                 printk(" [...]\n");
2459                 return;
2460         }
2461
2462         cursor_position = indent_level;
2463         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2464                 while (cursor_position < indent_level) {
2465                         printk(" ");
2466                         cursor_position++;
2467                 }
2468                 if (l->ref_cnt > 1)
2469                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2470                 else
2471                         indent_add = sprintf(buf, " --> ");
2472                 if (indent_level + indent_add >
2473                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2474                         printk("[...]\n");
2475                         cursor_position = 0;
2476                         continue;
2477                 }
2478
2479                 printk(buf);
2480
2481                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2482                                       indent_level + indent_add);
2483                 cursor_position = 0;
2484         }
2485 }
2486
2487 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2488                 struct btrfsic_state *state,
2489                 struct btrfsic_block_data_ctx *next_block_ctx,
2490                 struct btrfsic_block *next_block,
2491                 struct btrfsic_block *from_block,
2492                 u64 parent_generation)
2493 {
2494         struct btrfsic_block_link *l;
2495
2496         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2497                                                 next_block_ctx->dev_bytenr,
2498                                                 from_block->dev_state->bdev,
2499                                                 from_block->dev_bytenr,
2500                                                 &state->block_link_hashtable);
2501         if (NULL == l) {
2502                 l = btrfsic_block_link_alloc();
2503                 if (!l)
2504                         return NULL;
2505
2506                 l->block_ref_to = next_block;
2507                 l->block_ref_from = from_block;
2508                 l->ref_cnt = 1;
2509                 l->parent_generation = parent_generation;
2510
2511                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2512                         btrfsic_print_add_link(state, l);
2513
2514                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2515                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2516
2517                 btrfsic_block_link_hashtable_add(l,
2518                                                  &state->block_link_hashtable);
2519         } else {
2520                 l->ref_cnt++;
2521                 l->parent_generation = parent_generation;
2522                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2523                         btrfsic_print_add_link(state, l);
2524         }
2525
2526         return l;
2527 }
2528
2529 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2530                 struct btrfsic_state *state,
2531                 struct btrfsic_block_data_ctx *block_ctx,
2532                 const char *additional_string,
2533                 int is_metadata,
2534                 int is_iodone,
2535                 int never_written,
2536                 int mirror_num,
2537                 int *was_created)
2538 {
2539         struct btrfsic_block *block;
2540
2541         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2542                                                block_ctx->dev_bytenr,
2543                                                &state->block_hashtable);
2544         if (NULL == block) {
2545                 struct btrfsic_dev_state *dev_state;
2546
2547                 block = btrfsic_block_alloc();
2548                 if (!block)
2549                         return NULL;
2550
2551                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
2552                 if (NULL == dev_state) {
2553                         pr_info("btrfsic: error, lookup dev_state failed!\n");
2554                         btrfsic_block_free(block);
2555                         return NULL;
2556                 }
2557                 block->dev_state = dev_state;
2558                 block->dev_bytenr = block_ctx->dev_bytenr;
2559                 block->logical_bytenr = block_ctx->start;
2560                 block->is_metadata = is_metadata;
2561                 block->is_iodone = is_iodone;
2562                 block->never_written = never_written;
2563                 block->mirror_num = mirror_num;
2564                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2565                         pr_info("New %s%c-block @%llu (%pg/%llu/%d)\n",
2566                                additional_string,
2567                                btrfsic_get_block_type(state, block),
2568                                block->logical_bytenr, dev_state->bdev,
2569                                block->dev_bytenr, mirror_num);
2570                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2571                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2572                 if (NULL != was_created)
2573                         *was_created = 1;
2574         } else {
2575                 if (NULL != was_created)
2576                         *was_created = 0;
2577         }
2578
2579         return block;
2580 }
2581
2582 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2583                                            u64 bytenr,
2584                                            struct btrfsic_dev_state *dev_state,
2585                                            u64 dev_bytenr)
2586 {
2587         struct btrfs_fs_info *fs_info = state->fs_info;
2588         struct btrfsic_block_data_ctx block_ctx;
2589         int num_copies;
2590         int mirror_num;
2591         int match = 0;
2592         int ret;
2593
2594         num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
2595
2596         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2597                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2598                                         &block_ctx, mirror_num);
2599                 if (ret) {
2600                         pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2601                                bytenr, mirror_num);
2602                         continue;
2603                 }
2604
2605                 if (dev_state->bdev == block_ctx.dev->bdev &&
2606                     dev_bytenr == block_ctx.dev_bytenr) {
2607                         match++;
2608                         btrfsic_release_block_ctx(&block_ctx);
2609                         break;
2610                 }
2611                 btrfsic_release_block_ctx(&block_ctx);
2612         }
2613
2614         if (WARN_ON(!match)) {
2615                 pr_info(
2616 "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio, buffer->log_bytenr=%llu, submit_bio(bdev=%pg, phys_bytenr=%llu)!\n",
2617                        bytenr, dev_state->bdev, dev_bytenr);
2618                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2619                         ret = btrfsic_map_block(state, bytenr,
2620                                                 state->metablock_size,
2621                                                 &block_ctx, mirror_num);
2622                         if (ret)
2623                                 continue;
2624
2625                         pr_info("read logical bytenr @%llu maps to (%pg/%llu/%d)\n",
2626                                bytenr, block_ctx.dev->bdev,
2627                                block_ctx.dev_bytenr, mirror_num);
2628                 }
2629         }
2630 }
2631
2632 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
2633 {
2634         return btrfsic_dev_state_hashtable_lookup(dev,
2635                                                   &btrfsic_dev_state_hashtable);
2636 }
2637
2638 static void __btrfsic_submit_bio(struct bio *bio)
2639 {
2640         struct btrfsic_dev_state *dev_state;
2641
2642         if (!btrfsic_is_initialized)
2643                 return;
2644
2645         mutex_lock(&btrfsic_mutex);
2646         /* since btrfsic_submit_bio() is also called before
2647          * btrfsic_mount(), this might return NULL */
2648         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev->bd_dev);
2649         if (NULL != dev_state &&
2650             (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
2651                 int i = 0;
2652                 u64 dev_bytenr;
2653                 u64 cur_bytenr;
2654                 struct bio_vec bvec;
2655                 struct bvec_iter iter;
2656                 int bio_is_patched;
2657                 char **mapped_datav;
2658                 unsigned int segs = bio_segments(bio);
2659
2660                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2661                 bio_is_patched = 0;
2662                 if (dev_state->state->print_mask &
2663                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2664                         pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
2665                                bio_op(bio), bio->bi_opf, segs,
2666                                bio->bi_iter.bi_sector, dev_bytenr, bio->bi_bdev);
2667
2668                 mapped_datav = kmalloc_array(segs,
2669                                              sizeof(*mapped_datav), GFP_NOFS);
2670                 if (!mapped_datav)
2671                         goto leave;
2672                 cur_bytenr = dev_bytenr;
2673
2674                 bio_for_each_segment(bvec, bio, iter) {
2675                         BUG_ON(bvec.bv_len != PAGE_SIZE);
2676                         mapped_datav[i] = page_address(bvec.bv_page);
2677                         i++;
2678
2679                         if (dev_state->state->print_mask &
2680                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2681                                 pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2682                                        i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
2683                         cur_bytenr += bvec.bv_len;
2684                 }
2685                 btrfsic_process_written_block(dev_state, dev_bytenr,
2686                                               mapped_datav, segs,
2687                                               bio, &bio_is_patched,
2688                                               bio->bi_opf);
2689                 kfree(mapped_datav);
2690         } else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
2691                 if (dev_state->state->print_mask &
2692                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2693                         pr_info("submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
2694                                bio_op(bio), bio->bi_opf, bio->bi_bdev);
2695                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2696                         if ((dev_state->state->print_mask &
2697                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2698                               BTRFSIC_PRINT_MASK_VERBOSE)))
2699                                 pr_info(
2700 "btrfsic_submit_bio(%pg) with FLUSH but dummy block already in use (ignored)!\n",
2701                                        dev_state->bdev);
2702                 } else {
2703                         struct btrfsic_block *const block =
2704                                 &dev_state->dummy_block_for_bio_bh_flush;
2705
2706                         block->is_iodone = 0;
2707                         block->never_written = 0;
2708                         block->iodone_w_error = 0;
2709                         block->flush_gen = dev_state->last_flush_gen + 1;
2710                         block->submit_bio_bh_rw = bio->bi_opf;
2711                         block->orig_bio_private = bio->bi_private;
2712                         block->orig_bio_end_io = bio->bi_end_io;
2713                         block->next_in_same_bio = NULL;
2714                         bio->bi_private = block;
2715                         bio->bi_end_io = btrfsic_bio_end_io;
2716                 }
2717         }
2718 leave:
2719         mutex_unlock(&btrfsic_mutex);
2720 }
2721
2722 void btrfsic_submit_bio(struct bio *bio)
2723 {
2724         __btrfsic_submit_bio(bio);
2725         submit_bio(bio);
2726 }
2727
2728 int btrfsic_submit_bio_wait(struct bio *bio)
2729 {
2730         __btrfsic_submit_bio(bio);
2731         return submit_bio_wait(bio);
2732 }
2733
2734 int btrfsic_mount(struct btrfs_fs_info *fs_info,
2735                   struct btrfs_fs_devices *fs_devices,
2736                   int including_extent_data, u32 print_mask)
2737 {
2738         int ret;
2739         struct btrfsic_state *state;
2740         struct list_head *dev_head = &fs_devices->devices;
2741         struct btrfs_device *device;
2742
2743         if (!PAGE_ALIGNED(fs_info->nodesize)) {
2744                 pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2745                        fs_info->nodesize, PAGE_SIZE);
2746                 return -1;
2747         }
2748         if (!PAGE_ALIGNED(fs_info->sectorsize)) {
2749                 pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2750                        fs_info->sectorsize, PAGE_SIZE);
2751                 return -1;
2752         }
2753         state = kvzalloc(sizeof(*state), GFP_KERNEL);
2754         if (!state)
2755                 return -ENOMEM;
2756
2757         if (!btrfsic_is_initialized) {
2758                 mutex_init(&btrfsic_mutex);
2759                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2760                 btrfsic_is_initialized = 1;
2761         }
2762         mutex_lock(&btrfsic_mutex);
2763         state->fs_info = fs_info;
2764         state->print_mask = print_mask;
2765         state->include_extent_data = including_extent_data;
2766         state->metablock_size = fs_info->nodesize;
2767         state->datablock_size = fs_info->sectorsize;
2768         INIT_LIST_HEAD(&state->all_blocks_list);
2769         btrfsic_block_hashtable_init(&state->block_hashtable);
2770         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2771         state->max_superblock_generation = 0;
2772         state->latest_superblock = NULL;
2773
2774         list_for_each_entry(device, dev_head, dev_list) {
2775                 struct btrfsic_dev_state *ds;
2776
2777                 if (!device->bdev || !device->name)
2778                         continue;
2779
2780                 ds = btrfsic_dev_state_alloc();
2781                 if (NULL == ds) {
2782                         mutex_unlock(&btrfsic_mutex);
2783                         return -ENOMEM;
2784                 }
2785                 ds->bdev = device->bdev;
2786                 ds->state = state;
2787                 btrfsic_dev_state_hashtable_add(ds,
2788                                                 &btrfsic_dev_state_hashtable);
2789         }
2790
2791         ret = btrfsic_process_superblock(state, fs_devices);
2792         if (0 != ret) {
2793                 mutex_unlock(&btrfsic_mutex);
2794                 btrfsic_unmount(fs_devices);
2795                 return ret;
2796         }
2797
2798         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2799                 btrfsic_dump_database(state);
2800         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2801                 btrfsic_dump_tree(state);
2802
2803         mutex_unlock(&btrfsic_mutex);
2804         return 0;
2805 }
2806
2807 void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
2808 {
2809         struct btrfsic_block *b_all, *tmp_all;
2810         struct btrfsic_state *state;
2811         struct list_head *dev_head = &fs_devices->devices;
2812         struct btrfs_device *device;
2813
2814         if (!btrfsic_is_initialized)
2815                 return;
2816
2817         mutex_lock(&btrfsic_mutex);
2818
2819         state = NULL;
2820         list_for_each_entry(device, dev_head, dev_list) {
2821                 struct btrfsic_dev_state *ds;
2822
2823                 if (!device->bdev || !device->name)
2824                         continue;
2825
2826                 ds = btrfsic_dev_state_hashtable_lookup(
2827                                 device->bdev->bd_dev,
2828                                 &btrfsic_dev_state_hashtable);
2829                 if (NULL != ds) {
2830                         state = ds->state;
2831                         btrfsic_dev_state_hashtable_remove(ds);
2832                         btrfsic_dev_state_free(ds);
2833                 }
2834         }
2835
2836         if (NULL == state) {
2837                 pr_info("btrfsic: error, cannot find state information on umount!\n");
2838                 mutex_unlock(&btrfsic_mutex);
2839                 return;
2840         }
2841
2842         /*
2843          * Don't care about keeping the lists' state up to date,
2844          * just free all memory that was allocated dynamically.
2845          * Free the blocks and the block_links.
2846          */
2847         list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
2848                                  all_blocks_node) {
2849                 struct btrfsic_block_link *l, *tmp;
2850
2851                 list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
2852                                          node_ref_to) {
2853                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2854                                 btrfsic_print_rem_link(state, l);
2855
2856                         l->ref_cnt--;
2857                         if (0 == l->ref_cnt)
2858                                 btrfsic_block_link_free(l);
2859                 }
2860
2861                 if (b_all->is_iodone || b_all->never_written)
2862                         btrfsic_block_free(b_all);
2863                 else
2864                         pr_info(
2865 "btrfs: attempt to free %c-block @%llu (%pg/%llu/%d) on umount which is not yet iodone!\n",
2866                                btrfsic_get_block_type(state, b_all),
2867                                b_all->logical_bytenr, b_all->dev_state->bdev,
2868                                b_all->dev_bytenr, b_all->mirror_num);
2869         }
2870
2871         mutex_unlock(&btrfsic_mutex);
2872
2873         kvfree(state);
2874 }