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