block/fops.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 1991, 1992  Linus Torvalds
   4  * Copyright (C) 2001  Andrea Arcangeli <andrea@suse.de> SuSE
   5  * Copyright (C) 2016 - 2020 Christoph Hellwig
   6  */
   7 #include <linux/init.h>
   8 #include <linux/mm.h>
   9 #include <linux/blkdev.h>
  10 #include <linux/buffer_head.h>
  11 #include <linux/mpage.h>
  12 #include <linux/uio.h>
  13 #include <linux/namei.h>
  14 #include <linux/task_io_accounting_ops.h>
  15 #include <linux/falloc.h>
  16 #include <linux/suspend.h>
  17 #include <linux/fs.h>
  18 #include <linux/module.h>
  19 #include "blk.h"
  20
  21 static inline struct inode *bdev_file_inode(struct file *file)
  22 {
  23         return file->f_mapping->host;
  24 }
  25
  26 static int blkdev_get_block(struct inode *inode, sector_t iblock,
  27                 struct buffer_head *bh, int create)
  28 {
  29         bh->b_bdev = I_BDEV(inode);
  30         bh->b_blocknr = iblock;
  31         set_buffer_mapped(bh);
  32         return 0;
  33 }
  34
  35 static unsigned int dio_bio_write_op(struct kiocb *iocb)
  36 {
  37         unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
  38
  39         /* avoid the need for a I/O completion work item */
  40         if (iocb->ki_flags & IOCB_DSYNC)
  41                 op |= REQ_FUA;
  42         return op;
  43 }
  44
  45 #define DIO_INLINE_BIO_VECS 4
  46
  47 static void blkdev_bio_end_io_simple(struct bio *bio)
  48 {
  49         struct task_struct *waiter = bio->bi_private;
  50
  51         WRITE_ONCE(bio->bi_private, NULL);
  52         blk_wake_io_task(waiter);
  53 }
  54
  55 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
  56                 struct iov_iter *iter, unsigned int nr_pages)
  57 {
  58         struct block_device *bdev = iocb->ki_filp->private_data;
  59         struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
  60         loff_t pos = iocb->ki_pos;
  61         bool should_dirty = false;
  62         struct bio bio;
  63         ssize_t ret;
  64
  65         if ((pos | iov_iter_alignment(iter)) &
  66             (bdev_logical_block_size(bdev) - 1))
  67                 return -EINVAL;
  68
  69         if (nr_pages <= DIO_INLINE_BIO_VECS)
  70                 vecs = inline_vecs;
  71         else {
  72                 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),
  73                                      GFP_KERNEL);
  74                 if (!vecs)
  75                         return -ENOMEM;
  76         }
  77
  78         if (iov_iter_rw(iter) == READ) {
  79                 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
  80                 if (iter_is_iovec(iter))
  81                         should_dirty = true;
  82         } else {
  83                 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
  84         }
  85         bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
  86         bio.bi_private = current;
  87         bio.bi_end_io = blkdev_bio_end_io_simple;
  88         bio.bi_ioprio = iocb->ki_ioprio;
  89
  90         ret = bio_iov_iter_get_pages(&bio, iter);
  91         if (unlikely(ret))
  92                 goto out;
  93         ret = bio.bi_iter.bi_size;
  94
  95         if (iov_iter_rw(iter) == WRITE)
  96                 task_io_account_write(ret);
  97
  98         if (iocb->ki_flags & IOCB_NOWAIT)
  99                 bio.bi_opf |= REQ_NOWAIT;
 100         if (iocb->ki_flags & IOCB_HIPRI)
 101                 bio_set_polled(&bio, iocb);
 102
 103         submit_bio(&bio);
 104         for (;;) {
 105                 set_current_state(TASK_UNINTERRUPTIBLE);
 106                 if (!READ_ONCE(bio.bi_private))
 107                         break;
 108                 if (!(iocb->ki_flags & IOCB_HIPRI) || !bio_poll(&bio, NULL, 0))
 109                         blk_io_schedule();
 110         }
 111         __set_current_state(TASK_RUNNING);
 112
 113         bio_release_pages(&bio, should_dirty);
 114         if (unlikely(bio.bi_status))
 115                 ret = blk_status_to_errno(bio.bi_status);
 116
 117 out:
 118         if (vecs != inline_vecs)
 119                 kfree(vecs);
 120
 121         bio_uninit(&bio);
 122
 123         return ret;
 124 }
 125
 126 enum {
 127         DIO_SHOULD_DIRTY        = 1,
 128         DIO_IS_SYNC             = 2,
 129 };
 130
 131 struct blkdev_dio {
 132         union {
 133                 struct kiocb            *iocb;
 134                 struct task_struct      *waiter;
 135         };
 136         size_t                  size;
 137         atomic_t                ref;
 138         unsigned int            flags;
 139         struct bio              bio ____cacheline_aligned_in_smp;
 140 };
 141
 142 static struct bio_set blkdev_dio_pool;
 143
 144 static void blkdev_bio_end_io(struct bio *bio)
 145 {
 146         struct blkdev_dio *dio = bio->bi_private;
 147         bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
 148
 149         if (bio->bi_status && !dio->bio.bi_status)
 150                 dio->bio.bi_status = bio->bi_status;
 151
 152         if (atomic_dec_and_test(&dio->ref)) {
 153                 if (!(dio->flags & DIO_IS_SYNC)) {
 154                         struct kiocb *iocb = dio->iocb;
 155                         ssize_t ret;
 156
 157                         WRITE_ONCE(iocb->private, NULL);
 158
 159                         if (likely(!dio->bio.bi_status)) {
 160                                 ret = dio->size;
 161                                 iocb->ki_pos += ret;
 162                         } else {
 163                                 ret = blk_status_to_errno(dio->bio.bi_status);
 164                         }
 165
 166                         dio->iocb->ki_complete(iocb, ret);
 167                         bio_put(&dio->bio);
 168                 } else {
 169                         struct task_struct *waiter = dio->waiter;
 170
 171                         WRITE_ONCE(dio->waiter, NULL);
 172                         blk_wake_io_task(waiter);
 173                 }
 174         }
 175
 176         if (should_dirty) {
 177                 bio_check_pages_dirty(bio);
 178         } else {
 179                 bio_release_pages(bio, false);
 180                 bio_put(bio);
 181         }
 182 }
 183
 184 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 185                 unsigned int nr_pages)
 186 {
 187         struct block_device *bdev = iocb->ki_filp->private_data;
 188         struct blk_plug plug;
 189         struct blkdev_dio *dio;
 190         struct bio *bio;
 191         bool is_read = (iov_iter_rw(iter) == READ), is_sync;
 192         unsigned int opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
 193         loff_t pos = iocb->ki_pos;
 194         int ret = 0;
 195
 196         if ((pos | iov_iter_alignment(iter)) &
 197             (bdev_logical_block_size(bdev) - 1))
 198                 return -EINVAL;
 199
 200         bio = bio_alloc_kiocb(iocb, bdev, nr_pages, opf, &blkdev_dio_pool);
 201
 202         dio = container_of(bio, struct blkdev_dio, bio);
 203         atomic_set(&dio->ref, 1);
 204         /*
 205          * Grab an extra reference to ensure the dio structure which is embedded
 206          * into the first bio stays around.
 207          */
 208         bio_get(bio);
 209
 210         is_sync = is_sync_kiocb(iocb);
 211         if (is_sync) {
 212                 dio->flags = DIO_IS_SYNC;
 213                 dio->waiter = current;
 214         } else {
 215                 dio->flags = 0;
 216                 dio->iocb = iocb;
 217         }
 218
 219         dio->size = 0;
 220         if (is_read && iter_is_iovec(iter))
 221                 dio->flags |= DIO_SHOULD_DIRTY;
 222
 223         blk_start_plug(&plug);
 224
 225         for (;;) {
 226                 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
 227                 bio->bi_private = dio;
 228                 bio->bi_end_io = blkdev_bio_end_io;
 229                 bio->bi_ioprio = iocb->ki_ioprio;
 230
 231                 ret = bio_iov_iter_get_pages(bio, iter);
 232                 if (unlikely(ret)) {
 233                         bio->bi_status = BLK_STS_IOERR;
 234                         bio_endio(bio);
 235                         break;
 236                 }
 237
 238                 if (is_read) {
 239                         if (dio->flags & DIO_SHOULD_DIRTY)
 240                                 bio_set_pages_dirty(bio);
 241                 } else {
 242                         task_io_account_write(bio->bi_iter.bi_size);
 243                 }
 244                 if (iocb->ki_flags & IOCB_NOWAIT)
 245                         bio->bi_opf |= REQ_NOWAIT;
 246
 247                 dio->size += bio->bi_iter.bi_size;
 248                 pos += bio->bi_iter.bi_size;
 249
 250                 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
 251                 if (!nr_pages) {
 252                         submit_bio(bio);
 253                         break;
 254                 }
 255                 atomic_inc(&dio->ref);
 256                 submit_bio(bio);
 257                 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
 258         }
 259
 260         blk_finish_plug(&plug);
 261
 262         if (!is_sync)
 263                 return -EIOCBQUEUED;
 264
 265         for (;;) {
 266                 set_current_state(TASK_UNINTERRUPTIBLE);
 267                 if (!READ_ONCE(dio->waiter))
 268                         break;
 269                 blk_io_schedule();
 270         }
 271         __set_current_state(TASK_RUNNING);
 272
 273         if (!ret)
 274                 ret = blk_status_to_errno(dio->bio.bi_status);
 275         if (likely(!ret))
 276                 ret = dio->size;
 277
 278         bio_put(&dio->bio);
 279         return ret;
 280 }
 281
 282 static void blkdev_bio_end_io_async(struct bio *bio)
 283 {
 284         struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
 285         struct kiocb *iocb = dio->iocb;
 286         ssize_t ret;
 287
 288         WRITE_ONCE(iocb->private, NULL);
 289
 290         if (likely(!bio->bi_status)) {
 291                 ret = dio->size;
 292                 iocb->ki_pos += ret;
 293         } else {
 294                 ret = blk_status_to_errno(bio->bi_status);
 295         }
 296
 297         iocb->ki_complete(iocb, ret);
 298
 299         if (dio->flags & DIO_SHOULD_DIRTY) {
 300                 bio_check_pages_dirty(bio);
 301         } else {
 302                 bio_release_pages(bio, false);
 303                 bio_put(bio);
 304         }
 305 }
 306
 307 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
 308                                         struct iov_iter *iter,
 309                                         unsigned int nr_pages)
 310 {
 311         struct block_device *bdev = iocb->ki_filp->private_data;
 312         bool is_read = iov_iter_rw(iter) == READ;
 313         unsigned int opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
 314         struct blkdev_dio *dio;
 315         struct bio *bio;
 316         loff_t pos = iocb->ki_pos;
 317         int ret = 0;
 318
 319         if ((pos | iov_iter_alignment(iter)) &
 320             (bdev_logical_block_size(bdev) - 1))
 321                 return -EINVAL;
 322
 323         bio = bio_alloc_kiocb(iocb, bdev, nr_pages, opf, &blkdev_dio_pool);
 324         dio = container_of(bio, struct blkdev_dio, bio);
 325         dio->flags = 0;
 326         dio->iocb = iocb;
 327         bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
 328         bio->bi_end_io = blkdev_bio_end_io_async;
 329         bio->bi_ioprio = iocb->ki_ioprio;
 330
 331         if (iov_iter_is_bvec(iter)) {
 332                 /*
 333                  * Users don't rely on the iterator being in any particular
 334                  * state for async I/O returning -EIOCBQUEUED, hence we can
 335                  * avoid expensive iov_iter_advance(). Bypass
 336                  * bio_iov_iter_get_pages() and set the bvec directly.
 337                  */
 338                 bio_iov_bvec_set(bio, iter);
 339         } else {
 340                 ret = bio_iov_iter_get_pages(bio, iter);
 341                 if (unlikely(ret)) {
 342                         bio_put(bio);
 343                         return ret;
 344                 }
 345         }
 346         dio->size = bio->bi_iter.bi_size;
 347
 348         if (is_read) {
 349                 if (iter_is_iovec(iter)) {
 350                         dio->flags |= DIO_SHOULD_DIRTY;
 351                         bio_set_pages_dirty(bio);
 352                 }
 353         } else {
 354                 task_io_account_write(bio->bi_iter.bi_size);
 355         }
 356
 357         if (iocb->ki_flags & IOCB_HIPRI) {
 358                 bio->bi_opf |= REQ_POLLED | REQ_NOWAIT;
 359                 submit_bio(bio);
 360                 WRITE_ONCE(iocb->private, bio);
 361         } else {
 362                 if (iocb->ki_flags & IOCB_NOWAIT)
 363                         bio->bi_opf |= REQ_NOWAIT;
 364                 submit_bio(bio);
 365         }
 366         return -EIOCBQUEUED;
 367 }
 368
 369 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 370 {
 371         unsigned int nr_pages;
 372
 373         if (!iov_iter_count(iter))
 374                 return 0;
 375
 376         nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
 377         if (likely(nr_pages <= BIO_MAX_VECS)) {
 378                 if (is_sync_kiocb(iocb))
 379                         return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
 380                 return __blkdev_direct_IO_async(iocb, iter, nr_pages);
 381         }
 382         return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
 383 }
 384
 385 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
 386 {
 387         return block_write_full_page(page, blkdev_get_block, wbc);
 388 }
 389
 390 static int blkdev_read_folio(struct file *file, struct folio *folio)
 391 {
 392         return block_read_full_folio(folio, blkdev_get_block);
 393 }
 394
 395 static void blkdev_readahead(struct readahead_control *rac)
 396 {
 397         mpage_readahead(rac, blkdev_get_block);
 398 }
 399
 400 static int blkdev_write_begin(struct file *file, struct address_space *mapping,
 401                 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
 402 {
 403         return block_write_begin(mapping, pos, len, pagep, blkdev_get_block);
 404 }
 405
 406 static int blkdev_write_end(struct file *file, struct address_space *mapping,
 407                 loff_t pos, unsigned len, unsigned copied, struct page *page,
 408                 void *fsdata)
 409 {
 410         int ret;
 411         ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
 412
 413         unlock_page(page);
 414         put_page(page);
 415
 416         return ret;
 417 }
 418
 419 static int blkdev_writepages(struct address_space *mapping,
 420                              struct writeback_control *wbc)
 421 {
 422         return generic_writepages(mapping, wbc);
 423 }
 424
 425 const struct address_space_operations def_blk_aops = {
 426         .dirty_folio    = block_dirty_folio,
 427         .invalidate_folio = block_invalidate_folio,
 428         .read_folio     = blkdev_read_folio,
 429         .readahead      = blkdev_readahead,
 430         .writepage      = blkdev_writepage,
 431         .write_begin    = blkdev_write_begin,
 432         .write_end      = blkdev_write_end,
 433         .writepages     = blkdev_writepages,
 434         .direct_IO      = blkdev_direct_IO,
 435         .migratepage    = buffer_migrate_page_norefs,
 436         .is_dirty_writeback = buffer_check_dirty_writeback,
 437 };
 438
 439 /*
 440  * for a block special file file_inode(file)->i_size is zero
 441  * so we compute the size by hand (just as in block_read/write above)
 442  */
 443 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
 444 {
 445         struct inode *bd_inode = bdev_file_inode(file);
 446         loff_t retval;
 447
 448         inode_lock(bd_inode);
 449         retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
 450         inode_unlock(bd_inode);
 451         return retval;
 452 }
 453
 454 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
 455                 int datasync)
 456 {
 457         struct block_device *bdev = filp->private_data;
 458         int error;
 459
 460         error = file_write_and_wait_range(filp, start, end);
 461         if (error)
 462                 return error;
 463
 464         /*
 465          * There is no need to serialise calls to blkdev_issue_flush with
 466          * i_mutex and doing so causes performance issues with concurrent
 467          * O_SYNC writers to a block device.
 468          */
 469         error = blkdev_issue_flush(bdev);
 470         if (error == -EOPNOTSUPP)
 471                 error = 0;
 472
 473         return error;
 474 }
 475
 476 static int blkdev_open(struct inode *inode, struct file *filp)
 477 {
 478         struct block_device *bdev;
 479
 480         /*
 481          * Preserve backwards compatibility and allow large file access
 482          * even if userspace doesn't ask for it explicitly. Some mkfs
 483          * binary needs it. We might want to drop this workaround
 484          * during an unstable branch.
 485          */
 486         filp->f_flags |= O_LARGEFILE;
 487         filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
 488
 489         if (filp->f_flags & O_NDELAY)
 490                 filp->f_mode |= FMODE_NDELAY;
 491         if (filp->f_flags & O_EXCL)
 492                 filp->f_mode |= FMODE_EXCL;
 493         if ((filp->f_flags & O_ACCMODE) == 3)
 494                 filp->f_mode |= FMODE_WRITE_IOCTL;
 495
 496         bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
 497         if (IS_ERR(bdev))
 498                 return PTR_ERR(bdev);
 499
 500         filp->private_data = bdev;
 501         filp->f_mapping = bdev->bd_inode->i_mapping;
 502         filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
 503         return 0;
 504 }
 505
 506 static int blkdev_close(struct inode *inode, struct file *filp)
 507 {
 508         struct block_device *bdev = filp->private_data;
 509
 510         blkdev_put(bdev, filp->f_mode);
 511         return 0;
 512 }
 513
 514 /*
 515  * Write data to the block device.  Only intended for the block device itself
 516  * and the raw driver which basically is a fake block device.
 517  *
 518  * Does not take i_mutex for the write and thus is not for general purpose
 519  * use.
 520  */
 521 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 522 {
 523         struct block_device *bdev = iocb->ki_filp->private_data;
 524         struct inode *bd_inode = bdev->bd_inode;
 525         loff_t size = bdev_nr_bytes(bdev);
 526         struct blk_plug plug;
 527         size_t shorted = 0;
 528         ssize_t ret;
 529
 530         if (bdev_read_only(bdev))
 531                 return -EPERM;
 532
 533         if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
 534                 return -ETXTBSY;
 535
 536         if (!iov_iter_count(from))
 537                 return 0;
 538
 539         if (iocb->ki_pos >= size)
 540                 return -ENOSPC;
 541
 542         if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
 543                 return -EOPNOTSUPP;
 544
 545         size -= iocb->ki_pos;
 546         if (iov_iter_count(from) > size) {
 547                 shorted = iov_iter_count(from) - size;
 548                 iov_iter_truncate(from, size);
 549         }
 550
 551         blk_start_plug(&plug);
 552         ret = __generic_file_write_iter(iocb, from);
 553         if (ret > 0)
 554                 ret = generic_write_sync(iocb, ret);
 555         iov_iter_reexpand(from, iov_iter_count(from) + shorted);
 556         blk_finish_plug(&plug);
 557         return ret;
 558 }
 559
 560 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 561 {
 562         struct block_device *bdev = iocb->ki_filp->private_data;
 563         loff_t size = bdev_nr_bytes(bdev);
 564         loff_t pos = iocb->ki_pos;
 565         size_t shorted = 0;
 566         ssize_t ret = 0;
 567         size_t count;
 568
 569         if (unlikely(pos + iov_iter_count(to) > size)) {
 570                 if (pos >= size)
 571                         return 0;
 572                 size -= pos;
 573                 shorted = iov_iter_count(to) - size;
 574                 iov_iter_truncate(to, size);
 575         }
 576
 577         count = iov_iter_count(to);
 578         if (!count)
 579                 goto reexpand; /* skip atime */
 580
 581         if (iocb->ki_flags & IOCB_DIRECT) {
 582                 struct address_space *mapping = iocb->ki_filp->f_mapping;
 583
 584                 if (iocb->ki_flags & IOCB_NOWAIT) {
 585                         if (filemap_range_needs_writeback(mapping, pos,
 586                                                           pos + count - 1)) {
 587                                 ret = -EAGAIN;
 588                                 goto reexpand;
 589                         }
 590                 } else {
 591                         ret = filemap_write_and_wait_range(mapping, pos,
 592                                                            pos + count - 1);
 593                         if (ret < 0)
 594                                 goto reexpand;
 595                 }
 596
 597                 file_accessed(iocb->ki_filp);
 598
 599                 ret = blkdev_direct_IO(iocb, to);
 600                 if (ret >= 0) {
 601                         iocb->ki_pos += ret;
 602                         count -= ret;
 603                 }
 604                 iov_iter_revert(to, count - iov_iter_count(to));
 605                 if (ret < 0 || !count)
 606                         goto reexpand;
 607         }
 608
 609         ret = filemap_read(iocb, to, ret);
 610
 611 reexpand:
 612         if (unlikely(shorted))
 613                 iov_iter_reexpand(to, iov_iter_count(to) + shorted);
 614         return ret;
 615 }
 616
 617 #define BLKDEV_FALLOC_FL_SUPPORTED                                      \
 618                 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |           \
 619                  FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
 620
 621 static long blkdev_fallocate(struct file *file, int mode, loff_t start,
 622                              loff_t len)
 623 {
 624         struct inode *inode = bdev_file_inode(file);
 625         struct block_device *bdev = I_BDEV(inode);
 626         loff_t end = start + len - 1;
 627         loff_t isize;
 628         int error;
 629
 630         /* Fail if we don't recognize the flags. */
 631         if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
 632                 return -EOPNOTSUPP;
 633
 634         /* Don't go off the end of the device. */
 635         isize = bdev_nr_bytes(bdev);
 636         if (start >= isize)
 637                 return -EINVAL;
 638         if (end >= isize) {
 639                 if (mode & FALLOC_FL_KEEP_SIZE) {
 640                         len = isize - start;
 641                         end = start + len - 1;
 642                 } else
 643                         return -EINVAL;
 644         }
 645
 646         /*
 647          * Don't allow IO that isn't aligned to logical block size.
 648          */
 649         if ((start | len) & (bdev_logical_block_size(bdev) - 1))
 650                 return -EINVAL;
 651
 652         filemap_invalidate_lock(inode->i_mapping);
 653
 654         /* Invalidate the page cache, including dirty pages. */
 655         error = truncate_bdev_range(bdev, file->f_mode, start, end);
 656         if (error)
 657                 goto fail;
 658
 659         switch (mode) {
 660         case FALLOC_FL_ZERO_RANGE:
 661         case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
 662                 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
 663                                              len >> SECTOR_SHIFT, GFP_KERNEL,
 664                                              BLKDEV_ZERO_NOUNMAP);
 665                 break;
 666         case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
 667                 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
 668                                              len >> SECTOR_SHIFT, GFP_KERNEL,
 669                                              BLKDEV_ZERO_NOFALLBACK);
 670                 break;
 671         case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE:
 672                 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
 673                                              len >> SECTOR_SHIFT, GFP_KERNEL, 0);
 674                 break;
 675         default:
 676                 error = -EOPNOTSUPP;
 677         }
 678
 679  fail:
 680         filemap_invalidate_unlock(inode->i_mapping);
 681         return error;
 682 }
 683
 684 const struct file_operations def_blk_fops = {
 685         .open           = blkdev_open,
 686         .release        = blkdev_close,
 687         .llseek         = blkdev_llseek,
 688         .read_iter      = blkdev_read_iter,
 689         .write_iter     = blkdev_write_iter,
 690         .iopoll         = iocb_bio_iopoll,
 691         .mmap           = generic_file_mmap,
 692         .fsync          = blkdev_fsync,
 693         .unlocked_ioctl = blkdev_ioctl,
 694 #ifdef CONFIG_COMPAT
 695         .compat_ioctl   = compat_blkdev_ioctl,
 696 #endif
 697         .splice_read    = generic_file_splice_read,
 698         .splice_write   = iter_file_splice_write,
 699         .fallocate      = blkdev_fallocate,
 700 };
 701
 702 static __init int blkdev_init(void)
 703 {
 704         return bioset_init(&blkdev_dio_pool, 4,
 705                                 offsetof(struct blkdev_dio, bio),
 706                                 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
 707 }
 708 module_init(blkdev_init);