linux/block/ioctl.c

868 lines
21 KiB

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 17:04:11 +09:00
block/ioctl: prefer different overflow check Running syzkaller with the newly reintroduced signed integer overflow sanitizer shows this report: [ 62.982337] ------------[ cut here ]------------ [ 62.985692] cgroup: Invalid name [ 62.986211] UBSAN: signed-integer-overflow in ../block/ioctl.c:36:46 [ 62.989370] 9pnet_fd: p9_fd_create_tcp (7343): problem connecting socket to 127.0.0.1 [ 62.992992] 9223372036854775807 + 4095 cannot be represented in type 'long long' [ 62.997827] 9pnet_fd: p9_fd_create_tcp (7345): problem connecting socket to 127.0.0.1 [ 62.999369] random: crng reseeded on system resumption [ 63.000634] GUP no longer grows the stack in syz-executor.2 (7353): 20002000-20003000 (20001000) [ 63.000668] CPU: 0 PID: 7353 Comm: syz-executor.2 Not tainted 6.8.0-rc2-00035-gb3ef86b5a957 #1 [ 63.000677] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 63.000682] Call Trace: [ 63.000686] <TASK> [ 63.000731] dump_stack_lvl+0x93/0xd0 [ 63.000919] __get_user_pages+0x903/0xd30 [ 63.001030] __gup_longterm_locked+0x153e/0x1ba0 [ 63.001041] ? _raw_read_unlock_irqrestore+0x17/0x50 [ 63.001072] ? try_get_folio+0x29c/0x2d0 [ 63.001083] internal_get_user_pages_fast+0x1119/0x1530 [ 63.001109] iov_iter_extract_pages+0x23b/0x580 [ 63.001206] bio_iov_iter_get_pages+0x4de/0x1220 [ 63.001235] iomap_dio_bio_iter+0x9b6/0x1410 [ 63.001297] __iomap_dio_rw+0xab4/0x1810 [ 63.001316] iomap_dio_rw+0x45/0xa0 [ 63.001328] ext4_file_write_iter+0xdde/0x1390 [ 63.001372] vfs_write+0x599/0xbd0 [ 63.001394] ksys_write+0xc8/0x190 [ 63.001403] do_syscall_64+0xd4/0x1b0 [ 63.001421] ? arch_exit_to_user_mode_prepare+0x3a/0x60 [ 63.001479] entry_SYSCALL_64_after_hwframe+0x6f/0x77 [ 63.001535] RIP: 0033:0x7f7fd3ebf539 [ 63.001551] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 [ 63.001562] RSP: 002b:00007f7fd32570c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 63.001584] RAX: ffffffffffffffda RBX: 00007f7fd3ff3f80 RCX: 00007f7fd3ebf539 [ 63.001590] RDX: 4db6d1e4f7e43360 RSI: 0000000020000000 RDI: 0000000000000004 [ 63.001595] RBP: 00007f7fd3f1e496 R08: 0000000000000000 R09: 0000000000000000 [ 63.001599] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 63.001604] R13: 0000000000000006 R14: 00007f7fd3ff3f80 R15: 00007ffd415ad2b8 ... [ 63.018142] ---[ end trace ]--- Historically, the signed integer overflow sanitizer did not work in the kernel due to its interaction with `-fwrapv` but this has since been changed [1] in the newest version of Clang; It was re-enabled in the kernel with Commit 557f8c582a9ba8ab ("ubsan: Reintroduce signed overflow sanitizer"). Let's rework this overflow checking logic to not actually perform an overflow during the check itself, thus avoiding the UBSAN splat. [1]: https://github.com/llvm/llvm-project/pull/82432 Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240507-b4-sio-block-ioctl-v3-1-ba0c2b32275e@google.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-07 03:53:49 +00:00
block: fix race between set_blocksize and read paths [ Upstream commit c0e473a0d226479e8e925d5ba93f751d8df628e9 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-23 12:53:42 -07:00
block: fix race between set_blocksize and read paths [ Upstream commit c0e473a0d226479e8e925d5ba93f751d8df628e9 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-23 12:53:42 -07:00
block: fix race between set_blocksize and read paths [ Upstream commit c0e473a0d226479e8e925d5ba93f751d8df628e9 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-23 12:53:42 -07:00
block: fix race between set_blocksize and read paths [ Upstream commit c0e473a0d226479e8e925d5ba93f751d8df628e9 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-23 12:53:42 -07:00
block: invalidate the page cache when issuing BLKZEROOUT Patch series "fallocate for block devices", v11. This is a patchset to fix page cache coherency with BLKZEROOUT and implement fallocate for block devices. The first patch is a fix to the existing BLKZEROOUT ioctl to invalidate the page cache if the zeroing command to the underlying device succeeds. Without this patch we still have the pagecache coherence bug that's been in the kernel forever. The second patch changes the internal block device functions to reject attempts to discard or zeroout that are not aligned to the logical block size. Previously, we only checked that the start/len parameters were 512-byte aligned, which caused kernel BUG_ONs for unaligned IOs to 4k-LBA devices. The third patch creates an fallocate handler for block devices, wires up the FALLOC_FL_PUNCH_HOLE flag to zeroing-discard, and connects FALLOC_FL_ZERO_RANGE to write-same so that we can have a consistent fallocate interface between files and block devices. It also allows the combination of PUNCH_HOLE and NO_HIDE_STALE to invoke non-zeroing discard. Test cases for the new block device fallocate are now in xfstests as generic/349-351. This patch (of 3): Invalidate the page cache (as a regular O_DIRECT write would do) to avoid returning stale cache contents at a later time. Link: http://lkml.kernel.org/r/147518378313.22791.16649519283678515021.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Brian Foster <bfoster@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 13:51:05 -07:00
block: invalidate the page cache when issuing BLKZEROOUT Patch series "fallocate for block devices", v11. This is a patchset to fix page cache coherency with BLKZEROOUT and implement fallocate for block devices. The first patch is a fix to the existing BLKZEROOUT ioctl to invalidate the page cache if the zeroing command to the underlying device succeeds. Without this patch we still have the pagecache coherence bug that's been in the kernel forever. The second patch changes the internal block device functions to reject attempts to discard or zeroout that are not aligned to the logical block size. Previously, we only checked that the start/len parameters were 512-byte aligned, which caused kernel BUG_ONs for unaligned IOs to 4k-LBA devices. The third patch creates an fallocate handler for block devices, wires up the FALLOC_FL_PUNCH_HOLE flag to zeroing-discard, and connects FALLOC_FL_ZERO_RANGE to write-same so that we can have a consistent fallocate interface between files and block devices. It also allows the combination of PUNCH_HOLE and NO_HIDE_STALE to invoke non-zeroing discard. Test cases for the new block device fallocate are now in xfstests as generic/349-351. This patch (of 3): Invalidate the page cache (as a regular O_DIRECT write would do) to avoid returning stale cache contents at a later time. Link: http://lkml.kernel.org/r/147518378313.22791.16649519283678515021.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Brian Foster <bfoster@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 13:51:05 -07:00
block: invalidate the page cache when issuing BLKZEROOUT Patch series "fallocate for block devices", v11. This is a patchset to fix page cache coherency with BLKZEROOUT and implement fallocate for block devices. The first patch is a fix to the existing BLKZEROOUT ioctl to invalidate the page cache if the zeroing command to the underlying device succeeds. Without this patch we still have the pagecache coherence bug that's been in the kernel forever. The second patch changes the internal block device functions to reject attempts to discard or zeroout that are not aligned to the logical block size. Previously, we only checked that the start/len parameters were 512-byte aligned, which caused kernel BUG_ONs for unaligned IOs to 4k-LBA devices. The third patch creates an fallocate handler for block devices, wires up the FALLOC_FL_PUNCH_HOLE flag to zeroing-discard, and connects FALLOC_FL_ZERO_RANGE to write-same so that we can have a consistent fallocate interface between files and block devices. It also allows the combination of PUNCH_HOLE and NO_HIDE_STALE to invoke non-zeroing discard. Test cases for the new block device fallocate are now in xfstests as generic/349-351. This patch (of 3): Invalidate the page cache (as a regular O_DIRECT write would do) to avoid returning stale cache contents at a later time. Link: http://lkml.kernel.org/r/147518378313.22791.16649519283678515021.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Brian Foster <bfoster@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 13:51:05 -07:00
block: invalidate the page cache when issuing BLKZEROOUT Patch series "fallocate for block devices", v11. This is a patchset to fix page cache coherency with BLKZEROOUT and implement fallocate for block devices. The first patch is a fix to the existing BLKZEROOUT ioctl to invalidate the page cache if the zeroing command to the underlying device succeeds. Without this patch we still have the pagecache coherence bug that's been in the kernel forever. The second patch changes the internal block device functions to reject attempts to discard or zeroout that are not aligned to the logical block size. Previously, we only checked that the start/len parameters were 512-byte aligned, which caused kernel BUG_ONs for unaligned IOs to 4k-LBA devices. The third patch creates an fallocate handler for block devices, wires up the FALLOC_FL_PUNCH_HOLE flag to zeroing-discard, and connects FALLOC_FL_ZERO_RANGE to write-same so that we can have a consistent fallocate interface between files and block devices. It also allows the combination of PUNCH_HOLE and NO_HIDE_STALE to invoke non-zeroing discard. Test cases for the new block device fallocate are now in xfstests as generic/349-351. This patch (of 3): Invalidate the page cache (as a regular O_DIRECT write would do) to avoid returning stale cache contents at a later time. Link: http://lkml.kernel.org/r/147518378313.22791.16649519283678515021.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Brian Foster <bfoster@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 13:51:05 -07:00
block: fix race between set_blocksize and read paths [ Upstream commit c0e473a0d226479e8e925d5ba93f751d8df628e9 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-23 12:53:42 -07:00
block: invalidate the page cache when issuing BLKZEROOUT Patch series "fallocate for block devices", v11. This is a patchset to fix page cache coherency with BLKZEROOUT and implement fallocate for block devices. The first patch is a fix to the existing BLKZEROOUT ioctl to invalidate the page cache if the zeroing command to the underlying device succeeds. Without this patch we still have the pagecache coherence bug that's been in the kernel forever. The second patch changes the internal block device functions to reject attempts to discard or zeroout that are not aligned to the logical block size. Previously, we only checked that the start/len parameters were 512-byte aligned, which caused kernel BUG_ONs for unaligned IOs to 4k-LBA devices. The third patch creates an fallocate handler for block devices, wires up the FALLOC_FL_PUNCH_HOLE flag to zeroing-discard, and connects FALLOC_FL_ZERO_RANGE to write-same so that we can have a consistent fallocate interface between files and block devices. It also allows the combination of PUNCH_HOLE and NO_HIDE_STALE to invoke non-zeroing discard. Test cases for the new block device fallocate are now in xfstests as generic/349-351. This patch (of 3): Invalidate the page cache (as a regular O_DIRECT write would do) to avoid returning stale cache contents at a later time. Link: http://lkml.kernel.org/r/147518378313.22791.16649519283678515021.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Brian Foster <bfoster@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 13:51:05 -07:00
block: fix race between set_blocksize and read paths [ Upstream commit c0e473a0d226479e8e925d5ba93f751d8df628e9 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-23 12:53:42 -07:00