linux.git/block/bdev.c, branch v6.1.168

block: fix race between set_blocksize and read paths

2025-12-06T21:12:14+00:00

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
Reviewed-by: Christoph Hellwig
Reviewed-by: Luis Chamberlain
Tested-by: Shin'ichiro Kawasaki
Link: https://lore.kernel.org/r/174543795699.4139148.2086129139322431423.stgit@frogsfrogsfrogs
Signed-off-by: Jens Axboe
[use bdev->bd_inode instead & fix small contextual changes]
Signed-off-by: Mahmoud Adam
Signed-off-by: Greg Kroah-Hartman

block: update the stable_writes flag in bdev_add

2024-01-10T16:10:32+00:00

[ Upstream commit 1898efcdbed32bb1c67269c985a50bab0dbc9493 ]

Propagate the per-queue stable_write flags into each bdev inode in bdev_add.
This makes sure devices that require stable writes have it set for I/O
on the block device node as well.

Note that this doesn't cover the case of a flag changing on a live device
yet.  We should handle that as well, but I plan to cover it as part of a
more general rework of how changing runtime paramters on block devices
works.

Fixes: 1cb039f3dc16 ("bdi: replace BDI_CAP_STABLE_WRITES with a queue and a sb flag")
Reported-by: Ilya Dryomov 
Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20231025141020.192413-3-hch@lst.de
Tested-by: Ilya Dryomov 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Christian Brauner 
Signed-off-by: Sasha Levin

vfs: support STATX_DIOALIGN on block devices

2022-09-12T00:47:12+00:00

Add support for STATX_DIOALIGN to block devices, so that direct I/O
alignment restrictions are exposed to userspace in a generic way.

Note that this breaks the tradition of stat operating only on the block
device node, not the block device itself.  However, it was felt that
doing this is preferable, in order to make the interface useful and
avoid needing separate interfaces for regular files and block devices.

Signed-off-by: Eric Biggers 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Christian Brauner (Microsoft) 
Link: https://lore.kernel.org/r/20220827065851.135710-3-ebiggers@kernel.org

block: stop using bdevname in bdev_write_inode

2022-07-14T16:27:56+00:00

Just use the %pg format specifier instead.  Also reformat the
printk statement to be more readable.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20220713055317.1888500-2-hch@lst.de
Signed-off-by: Jens Axboe

Merge tag 'exfat-for-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

2022-05-25T01:30:27+00:00

Pull exfat updates from Namjae Jeon:

 - fix referencing wrong parent directory information during rename

 - introduce a sys_tz mount option to use system timezone

 - improve performance while zeroing a cluster with dirsync mount option

 - fix slab-out-bounds in exat_clear_bitmap() reported from syzbot

* tag 'exfat-for-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: check if cluster num is valid
  exfat: reduce block requests when zeroing a cluster
  block: add sync_blockdev_range()
  exfat: introduce mount option 'sys_tz'
  exfat: fix referencing wrong parent directory information after renaming

block: add sync_blockdev_range()

2022-05-23T02:17:30+00:00

sync_blockdev_range() is to support syncing multiple sectors
with as few block device requests as possible, it is helpful
to make the block device to give full play to its performance.

Signed-off-by: Yuezhang Mo 
Suggested-by: Christoph Hellwig 
Reviewed-by: Andy Wu 
Reviewed-by: Aoyama Wataru 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jens Axboe 
Acked-by: Sungjong Seo 
Signed-off-by: Namjae Jeon

block: turn bdev->bd_openers into an atomic_t

2022-04-18T12:54:09+00:00

All manipulation of bd_openers is under disk->open_mutex and will remain
so for the foreseeable future.  But at least one place reads it without
the lock (blkdev_get) and there are more to be added.  So make sure the
compiler does not do turn the increments and decrements into non-atomic
sequences by using an atomic_t.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20220330052917.2566582-6-hch@lst.de
Signed-off-by: Jens Axboe

Merge branch 'akpm' (patches from Andrew)

2022-03-22T23:11:53+00:00

Merge updates from Andrew Morton:

 - A few misc subsystems: kthread, scripts, ntfs, ocfs2, block, and vfs

 - Most the MM patches which precede the patches in Willy's tree: kasan,
   pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap,
   sparsemem, vmalloc, pagealloc, memory-failure, mlock, hugetlb,
   userfaultfd, vmscan, compaction, mempolicy, oom-kill, migration, thp,
   cma, autonuma, psi, ksm, page-poison, madvise, memory-hotplug, rmap,
   zswap, uaccess, ioremap, highmem, cleanups, kfence, hmm, and damon.

* emailed patches from Andrew Morton : (227 commits)
  mm/damon/sysfs: remove repeat container_of() in damon_sysfs_kdamond_release()
  Docs/ABI/testing: add DAMON sysfs interface ABI document
  Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface
  selftests/damon: add a test for DAMON sysfs interface
  mm/damon/sysfs: support DAMOS stats
  mm/damon/sysfs: support DAMOS watermarks
  mm/damon/sysfs: support schemes prioritization
  mm/damon/sysfs: support DAMOS quotas
  mm/damon/sysfs: support DAMON-based Operation Schemes
  mm/damon/sysfs: support the physical address space monitoring
  mm/damon/sysfs: link DAMON for virtual address spaces monitoring
  mm/damon: implement a minimal stub for sysfs-based DAMON interface
  mm/damon/core: add number of each enum type values
  mm/damon/core: allow non-exclusive DAMON start/stop
  Docs/damon: update outdated term 'regions update interval'
  Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling
  Docs/vm/damon: call low level monitoring primitives the operations
  mm/damon: remove unnecessary CONFIG_DAMON option
  mm/damon/paddr,vaddr: remove damon_{p,v}a_{target_valid,set_operations}()
  mm/damon/dbgfs-test: fix is_target_id() change
  ...

fs: allocate inode by using alloc_inode_sb()

2022-03-22T22:57:03+00:00

The inode allocation is supposed to use alloc_inode_sb(), so convert
kmem_cache_alloc() of all filesystems to alloc_inode_sb().

Link: https://lkml.kernel.org/r/20220228122126.37293-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Acked-by: Theodore Ts'o 		[ext4]
Acked-by: Roman Gushchin 
Cc: Alex Shi 
Cc: Anna Schumaker 
Cc: Chao Yu 
Cc: Dave Chinner 
Cc: Fam Zheng 
Cc: Jaegeuk Kim 
Cc: Johannes Weiner 
Cc: Kari Argillander 
Cc: Matthew Wilcox (Oracle) 
Cc: Michal Hocko 
Cc: Qi Zheng 
Cc: Shakeel Butt 
Cc: Trond Myklebust 
Cc: Vladimir Davydov 
Cc: Vlastimil Babka 
Cc: Wei Yang 
Cc: Xiongchun Duan 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

block: remove redundant semicolon

2022-02-27T21:52:36+00:00

Remove redundant semicolon from block/bdev.c

Signed-off-by: Nian Yanchuan 
Link: https://lore.kernel.org/r/20220227170124.GA14658@localhost.localdomain
Signed-off-by: Jens Axboe