linux.git/block/fops.c, branch v6.1.168 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git block: fix race between set_blocksize and read paths 2025-12-06T21:12:14+00:00 Darrick J. Wong djwong@kernel.org 2025-10-21T07:03:42+00:00 311427c9384d93ce01f6375a83f93c1c18f7cabe commit c0e473a0d226479e8e925d5ba93f751d8df628e9 upstream. With the new large sector size support, it's now the case that set_blocksize can change i_blksize and the folio order in a manner that conflicts with a concurrent reader and causes a kernel crash. Specifically, let's say that udev-worker calls libblkid to detect the labels on a block device. The read call can create an order-0 folio to read the first 4096 bytes from the disk. But then udev is preempted. Next, someone tries to mount an 8k-sectorsize filesystem from the same block device. The filesystem calls set_blksize, which sets i_blksize to 8192 and the minimum folio order to 1. Now udev resumes, still holding the order-0 folio it allocated. It then tries to schedule a read bio and do_mpage_readahead tries to create bufferheads for the folio. Unfortunately, blocks_per_folio == 0 because the page size is 4096 but the blocksize is 8192 so no bufferheads are attached and the bh walk never sets bdev. We then submit the bio with a NULL block device and crash. Therefore, truncate the page cache after flushing but before updating i_blksize. However, that's not enough -- we also need to lock out file IO and page faults during the update. Take both the i_rwsem and the invalidate_lock in exclusive mode for invalidations, and in shared mode for read/write operations. I don't know if this is the correct fix, but xfs/259 found it. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Link: https://lore.kernel.org/r/174543795699.4139148.2086129139322431423.stgit@frogsfrogsfrogs Signed-off-by: Jens Axboe <axboe@kernel.dk> [use bdev->bd_inode instead & fix small contextual changes] Signed-off-by: Mahmoud Adam <mngyadam@amazon.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c0e473a0d226479e8e925d5ba93f751d8df628e9 upstream.

With the new large sector size support, it's now the case that
set_blocksize can change i_blksize and the folio order in a manner that
conflicts with a concurrent reader and causes a kernel crash.

Specifically, let's say that udev-worker calls libblkid to detect the
labels on a block device.  The read call can create an order-0 folio to
read the first 4096 bytes from the disk.  But then udev is preempted.

Next, someone tries to mount an 8k-sectorsize filesystem from the same
block device.  The filesystem calls set_blksize, which sets i_blksize to
8192 and the minimum folio order to 1.

Now udev resumes, still holding the order-0 folio it allocated.  It then
tries to schedule a read bio and do_mpage_readahead tries to create
bufferheads for the folio.  Unfortunately, blocks_per_folio == 0 because
the page size is 4096 but the blocksize is 8192 so no bufferheads are
attached and the bh walk never sets bdev.  We then submit the bio with a
NULL block device and crash.

Therefore, truncate the page cache after flushing but before updating
i_blksize.  However, that's not enough -- we also need to lock out file
IO and page faults during the update.  Take both the i_rwsem and the
invalidate_lock in exclusive mode for invalidations, and in shared mode
for read/write operations.

I don't know if this is the correct fix, but xfs/259 found it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/174543795699.4139148.2086129139322431423.stgit@frogsfrogsfrogs
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[use bdev->bd_inode instead & fix small contextual changes]
Signed-off-by: Mahmoud Adam <mngyadam@amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: open code __generic_file_write_iter for blkdev writes 2025-12-06T21:12:14+00:00 Christoph Hellwig hch@lst.de 2025-10-21T07:03:41+00:00 c21a9e0e4ef45b6e2ed7c967d3c1855bdbdbc2b7 commit 727cfe976758b79f8d2f8051c75a5ccb14539a56 upstream. Open code __generic_file_write_iter to remove the indirect call into ->direct_IO and to prepare using the iomap based write code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20230801172201.1923299-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> [fix contextual changes] Signed-off-by: Mahmoud Adam <mngyadam@amazon.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 727cfe976758b79f8d2f8051c75a5ccb14539a56 upstream.

Open code __generic_file_write_iter to remove the indirect call into
->direct_IO and to prepare using the iomap based write code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230801172201.1923299-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[fix contextual changes]
Signed-off-by: Mahmoud Adam <mngyadam@amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: don't revert iter for -EIOCBQUEUED 2025-02-21T12:49:45+00:00 Jens Axboe axboe@kernel.dk 2025-01-23T13:18:41+00:00 6c26619effb1b4cb7d20b4e666ab8f71f6a53ccb commit b13ee668e8280ca5b07f8ce2846b9957a8a10853 upstream. blkdev_read_iter() has a few odd checks, like gating the position and count adjustment on whether or not the result is bigger-than-or-equal to zero (where bigger than makes more sense), and not checking the return value of blkdev_direct_IO() before doing an iov_iter_revert(). The latter can lead to attempting to revert with a negative value, which when passed to iov_iter_revert() as an unsigned value will lead to throwing a WARN_ON() because unroll is bigger than MAX_RW_COUNT. Be sane and don't revert for -EIOCBQUEUED, like what is done in other spots. Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b13ee668e8280ca5b07f8ce2846b9957a8a10853 upstream.

blkdev_read_iter() has a few odd checks, like gating the position and
count adjustment on whether or not the result is bigger-than-or-equal to
zero (where bigger than makes more sense), and not checking the return
value of blkdev_direct_IO() before doing an iov_iter_revert(). The
latter can lead to attempting to revert with a negative value, which
when passed to iov_iter_revert() as an unsigned value will lead to
throwing a WARN_ON() because unroll is bigger than MAX_RW_COUNT.

Be sane and don't revert for -EIOCBQUEUED, like what is done in other
spots.

Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: Don't invalidate pagecache for invalid falloc modes 2024-01-10T16:10:20+00:00 Sarthak Kukreti sarthakkukreti@chromium.org 2023-10-11T20:12:30+00:00 9539e3b56e0d822de3807d56c90545ef650467ab commit 1364a3c391aedfeb32aa025303ead3d7c91cdf9d upstream. Only call truncate_bdev_range() if the fallocate mode is supported. This fixes a bug where data in the pagecache could be invalidated if the fallocate() was called on the block device with an invalid mode. Fixes: 25f4c41415e5 ("block: implement (some of) fallocate for block devices") Cc: stable@vger.kernel.org Reported-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Fixes: line? I've never seen those wrapped. Link: https://lore.kernel.org/r/20231011201230.750105-1-sarthakkukreti@chromium.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1364a3c391aedfeb32aa025303ead3d7c91cdf9d upstream.

Only call truncate_bdev_range() if the fallocate mode is supported. This
fixes a bug where data in the pagecache could be invalidated if the
fallocate() was called on the block device with an invalid mode.

Fixes: 25f4c41415e5 ("block: implement (some of) fallocate for block devices")
Cc: stable@vger.kernel.org
Reported-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Fixes: line?  I've never seen those wrapped.
Link: https://lore.kernel.org/r/20231011201230.750105-1-sarthakkukreti@chromium.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: Deny writable memory mapping if block is read-only 2023-06-09T08:34:17+00:00 Loic Poulain loic.poulain@linaro.org 2023-05-10T07:42:23+00:00 7df6008b872693b5aa7da2aa35a3935c175dbff6 [ Upstream commit 69baa3a623fd2e58624f24f2f23d46f87b817c93 ] User should not be able to write block device if it is read-only at block level (e.g force_ro attribute). This is ensured in the regular fops write operation (blkdev_write_iter) but not when writing via user mapping (mmap), allowing user to actually write a read-only block device via a PROT_WRITE mapping. Example: This can lead to integrity issue of eMMC boot partition (e.g mmcblk0boot0) which is read-only by default. To fix this issue, simply deny shared writable mapping if the block is readonly. Note: Block remains writable if switch to read-only is performed after the initial mapping, but this is expected behavior according to commit a32e236eb93e ("Partially revert "block: fail op_is_write() requests to read-only partitions"")'. Signed-off-by: Loic Poulain <loic.poulain@linaro.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230510074223.991297-1-loic.poulain@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 69baa3a623fd2e58624f24f2f23d46f87b817c93 ]

User should not be able to write block device if it is read-only at
block level (e.g force_ro attribute). This is ensured in the regular
fops write operation (blkdev_write_iter) but not when writing via
user mapping (mmap), allowing user to actually write a read-only
block device via a PROT_WRITE mapping.

Example: This can lead to integrity issue of eMMC boot partition
(e.g mmcblk0boot0) which is read-only by default.

To fix this issue, simply deny shared writable mapping if the block
is readonly.

Note: Block remains writable if switch to read-only is performed
after the initial mapping, but this is expected behavior according
to commit a32e236eb93e ("Partially revert "block: fail op_is_write()
requests to read-only partitions"")'.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230510074223.991297-1-loic.poulain@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block: don't allow multiple bios for IOCB_NOWAIT issue 2023-03-10T08:34:02+00:00 Jens Axboe axboe@kernel.dk 2023-01-16T15:55:53+00:00 1796bc1e4499cedb3ba61c1068130d19ebae0b44 commit 67d59247d4b52c917e373f05a807027756ab216f upstream. If we're doing a large IO request which needs to be split into multiple bios for issue, then we can run into the same situation as the below marked commit fixes - parts will complete just fine, one or more parts will fail to allocate a request. This will result in a partially completed read or write request, where the caller gets EAGAIN even though parts of the IO completed just fine. Do the same for large bios as we do for splits - fail a NOWAIT request with EAGAIN. This isn't technically fixing an issue in the below marked patch, but for stable purposes, we should have either none of them or both. This depends on: 613b14884b85 ("block: handle bio_split_to_limits() NULL return") Cc: stable@vger.kernel.org # 5.15+ Fixes: 9cea62b2cbab ("block: don't allow splitting of a REQ_NOWAIT bio") Link: https://github.com/axboe/liburing/issues/766 Reported-and-tested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 67d59247d4b52c917e373f05a807027756ab216f upstream.

If we're doing a large IO request which needs to be split into multiple
bios for issue, then we can run into the same situation as the below
marked commit fixes - parts will complete just fine, one or more parts
will fail to allocate a request. This will result in a partially
completed read or write request, where the caller gets EAGAIN even though
parts of the IO completed just fine.

Do the same for large bios as we do for splits - fail a NOWAIT request
with EAGAIN. This isn't technically fixing an issue in the below marked
patch, but for stable purposes, we should have either none of them or
both.

This depends on: 613b14884b85 ("block: handle bio_split_to_limits() NULL return")

Cc: stable@vger.kernel.org # 5.15+
Fixes: 9cea62b2cbab ("block: don't allow splitting of a REQ_NOWAIT bio")
Link: https://github.com/axboe/liburing/issues/766
Reported-and-tested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
new iov_iter flavour - ITER_UBUF 2022-08-09T02:37:15+00:00 Al Viro viro@zeniv.linux.org.uk 2022-05-22T18:59:25+00:00 fcb14cb1bdacec5b4374fe161e83fb8208164a85 Equivalent of single-segment iovec. Initialized by iov_iter_ubuf(), checked for by iter_is_ubuf(), otherwise behaves like ITER_IOVEC ones. We are going to expose the things like ->write_iter() et.al. to those in subsequent commits. New predicate (user_backed_iter()) that is true for ITER_IOVEC and ITER_UBUF; places like direct-IO handling should use that for checking that pages we modify after getting them from iov_iter_get_pages() would need to be dirtied. DO NOT assume that replacing iter_is_iovec() with user_backed_iter() will solve all problems - there's code that uses iter_is_iovec() to decide how to poke around in iov_iter guts and for that the predicate replacement obviously won't suffice. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
Equivalent of single-segment iovec.  Initialized by iov_iter_ubuf(),
checked for by iter_is_ubuf(), otherwise behaves like ITER_IOVEC
ones.

We are going to expose the things like ->write_iter() et.al. to those
in subsequent commits.

New predicate (user_backed_iter()) that is true for ITER_IOVEC and
ITER_UBUF; places like direct-IO handling should use that for
checking that pages we modify after getting them from iov_iter_get_pages()
would need to be dirtied.

DO NOT assume that replacing iter_is_iovec() with user_backed_iter()
will solve all problems - there's code that uses iter_is_iovec() to
decide how to poke around in iov_iter guts and for that the predicate
replacement obviously won't suffice.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-08-03T20:50:22+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-08-03T20:50:22+00:00 5264406cdb66c7003eb3edf53c9773b1b20611b9 Pull vfs iov_iter updates from Al Viro: "Part 1 - isolated cleanups and optimizations. One of the goals is to reduce the overhead of using ->read_iter() and ->write_iter() instead of ->read()/->write(). new_sync_{read,write}() has a surprising amount of overhead, in particular inside iocb_flags(). That's the explanation for the beginning of the series is in this pile; it's not directly iov_iter-related, but it's a part of the same work..." * tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: first_iovec_segment(): just return address iov_iter: massage calling conventions for first_{iovec,bvec}_segment() iov_iter: first_{iovec,bvec}_segment() - simplify a bit iov_iter: lift dealing with maxpages out of first_{iovec,bvec}_segment() iov_iter_get_pages{,_alloc}(): cap the maxsize with MAX_RW_COUNT iov_iter_bvec_advance(): don't bother with bvec_iter copy_page_{to,from}_iter(): switch iovec variants to generic keep iocb_flags() result cached in struct file iocb: delay evaluation of IS_SYNC(...) until we want to check IOCB_DSYNC struct file: use anonymous union member for rcuhead and llist btrfs: use IOMAP_DIO_NOSYNC teach iomap_dio_rw() to suppress dsync No need of likely/unlikely on calls of check_copy_size() 
Pull vfs iov_iter updates from Al Viro:
 "Part 1 - isolated cleanups and optimizations.

  One of the goals is to reduce the overhead of using ->read_iter() and
  ->write_iter() instead of ->read()/->write().

  new_sync_{read,write}() has a surprising amount of overhead, in
  particular inside iocb_flags(). That's the explanation for the
  beginning of the series is in this pile; it's not directly
  iov_iter-related, but it's a part of the same work..."

* tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  first_iovec_segment(): just return address
  iov_iter: massage calling conventions for first_{iovec,bvec}_segment()
  iov_iter: first_{iovec,bvec}_segment() - simplify a bit
  iov_iter: lift dealing with maxpages out of first_{iovec,bvec}_segment()
  iov_iter_get_pages{,_alloc}(): cap the maxsize with MAX_RW_COUNT
  iov_iter_bvec_advance(): don't bother with bvec_iter
  copy_page_{to,from}_iter(): switch iovec variants to generic
  keep iocb_flags() result cached in struct file
  iocb: delay evaluation of IS_SYNC(...) until we want to check IOCB_DSYNC
  struct file: use anonymous union member for rcuhead and llist
  btrfs: use IOMAP_DIO_NOSYNC
  teach iomap_dio_rw() to suppress dsync
  No need of likely/unlikely on calls of check_copy_size()
Merge tag 'folio-6.0' of git://git.infradead.org/users/willy/pagecache 2022-08-03T17:35:43+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-08-03T17:35:43+00:00 f00654007fe1c154dafbdc1f5953c132e8c27c38 Pull folio updates from Matthew Wilcox: - Fix an accounting bug that made NR_FILE_DIRTY grow without limit when running xfstests - Convert more of mpage to use folios - Remove add_to_page_cache() and add_to_page_cache_locked() - Convert find_get_pages_range() to filemap_get_folios() - Improvements to the read_cache_page() family of functions - Remove a few unnecessary checks of PageError - Some straightforward filesystem conversions to use folios - Split PageMovable users out from address_space_operations into their own movable_operations - Convert aops->migratepage to aops->migrate_folio - Remove nobh support (Christoph Hellwig) * tag 'folio-6.0' of git://git.infradead.org/users/willy/pagecache: (78 commits) fs: remove the NULL get_block case in mpage_writepages fs: don't call ->writepage from __mpage_writepage fs: remove the nobh helpers jfs: stop using the nobh helper ext2: remove nobh support ntfs3: refactor ntfs_writepages mm/folio-compat: Remove migration compatibility functions fs: Remove aops->migratepage() secretmem: Convert to migrate_folio hugetlb: Convert to migrate_folio aio: Convert to migrate_folio f2fs: Convert to filemap_migrate_folio() ubifs: Convert to filemap_migrate_folio() btrfs: Convert btrfs_migratepage to migrate_folio mm/migrate: Add filemap_migrate_folio() mm/migrate: Convert migrate_page() to migrate_folio() nfs: Convert to migrate_folio btrfs: Convert btree_migratepage to migrate_folio mm/migrate: Convert expected_page_refs() to folio_expected_refs() mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio() ... 
Pull folio updates from Matthew Wilcox:

 - Fix an accounting bug that made NR_FILE_DIRTY grow without limit
   when running xfstests

 - Convert more of mpage to use folios

 - Remove add_to_page_cache() and add_to_page_cache_locked()

 - Convert find_get_pages_range() to filemap_get_folios()

 - Improvements to the read_cache_page() family of functions

 - Remove a few unnecessary checks of PageError

 - Some straightforward filesystem conversions to use folios

 - Split PageMovable users out from address_space_operations into
   their own movable_operations

 - Convert aops->migratepage to aops->migrate_folio

 - Remove nobh support (Christoph Hellwig)

* tag 'folio-6.0' of git://git.infradead.org/users/willy/pagecache: (78 commits)
  fs: remove the NULL get_block case in mpage_writepages
  fs: don't call ->writepage from __mpage_writepage
  fs: remove the nobh helpers
  jfs: stop using the nobh helper
  ext2: remove nobh support
  ntfs3: refactor ntfs_writepages
  mm/folio-compat: Remove migration compatibility functions
  fs: Remove aops->migratepage()
  secretmem: Convert to migrate_folio
  hugetlb: Convert to migrate_folio
  aio: Convert to migrate_folio
  f2fs: Convert to filemap_migrate_folio()
  ubifs: Convert to filemap_migrate_folio()
  btrfs: Convert btrfs_migratepage to migrate_folio
  mm/migrate: Add filemap_migrate_folio()
  mm/migrate: Convert migrate_page() to migrate_folio()
  nfs: Convert to migrate_folio
  btrfs: Convert btree_migratepage to migrate_folio
  mm/migrate: Convert expected_page_refs() to folio_expected_refs()
  mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio()
  ...
mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio() 2022-08-02T16:34:03+00:00 Matthew Wilcox (Oracle) willy@infradead.org 2022-06-06T14:20:31+00:00 67235182a41c1bd6b32806a1556a1d299b84212b Use a folio throughout __buffer_migrate_folio(), add kernel-doc for buffer_migrate_folio() and buffer_migrate_folio_norefs(), move their declarations to buffer.h and switch all filesystems that have wired them up. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> 
Use a folio throughout __buffer_migrate_folio(), add kernel-doc for
buffer_migrate_folio() and buffer_migrate_folio_norefs(), move their
declarations to buffer.h and switch all filesystems that have wired
them up.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>