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Avoids fun races in RCU pathwalk... Same goes for freeing LSM shite
hanging off super_block's arse.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Pull fscrypt updates from Eric Biggers:
"Adjust the timing of the fscrypt keyring destruction, to prepare for
btrfs's fscrypt support.
Also document that CephFS supports fscrypt now"
* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux:
fs: move fscrypt keyring destruction to after ->put_super
f2fs: move release of block devices to after kill_block_super()
fscrypt: document that CephFS supports fscrypt now
fscrypt: update comment for do_remove_key()
fscrypt.rst: update definition of struct fscrypt_context_v2
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs super updates from Christian Brauner:
"This contains the super work for this cycle including the long-awaited
series by Jan to make it possible to prevent writing to mounted block
devices:
- Writing to mounted devices is dangerous and can lead to filesystem
corruption as well as crashes. Furthermore syzbot comes with more
and more involved examples how to corrupt block device under a
mounted filesystem leading to kernel crashes and reports we can do
nothing about. Add tracking of writers to each block device and a
kernel cmdline argument which controls whether other writeable
opens to block devices open with BLK_OPEN_RESTRICT_WRITES flag are
allowed.
Note that this effectively only prevents modification of the
particular block device's page cache by other writers. The actual
device content can still be modified by other means - e.g. by
issuing direct scsi commands, by doing writes through devices lower
in the storage stack (e.g. in case loop devices, DM, or MD are
involved) etc. But blocking direct modifications of the block
device page cache is enough to give filesystems a chance to perform
data validation when loading data from the underlying storage and
thus prevent kernel crashes.
Syzbot can use this cmdline argument option to avoid uninteresting
crashes. Also users whose userspace setup does not need writing to
mounted block devices can set this option for hardening. We expect
that this will be interesting to quite a few workloads.
Btrfs is currently opted out of this because they still haven't
merged patches we require for this to work from three kernel
releases ago.
- Reimplement block device freezing and thawing as holder operations
on the block device.
This allows us to extend block device freezing to all devices
associated with a superblock and not just the main device. It also
allows us to remove get_active_super() and thus another function
that scans the global list of superblocks.
Freezing via additional block devices only works if the filesystem
chooses to use @fs_holder_ops for these additional devices as well.
That currently only includes ext4 and xfs.
Earlier releases switched get_tree_bdev() and mount_bdev() to use
@fs_holder_ops. The remaining nilfs2 open-coded version of
mount_bdev() has been converted to rely on @fs_holder_ops as well.
So block device freezing for the main block device will continue to
work as before.
There should be no regressions in functionality. The only special
case is btrfs where block device freezing for the main block device
never worked because sb->s_bdev isn't set. Block device freezing
for btrfs can be fixed once they can switch to @fs_holder_ops but
that can happen whenever they're ready"
* tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits)
block: Fix a memory leak in bdev_open_by_dev()
super: don't bother with WARN_ON_ONCE()
super: massage wait event mechanism
ext4: Block writes to journal device
xfs: Block writes to log device
fs: Block writes to mounted block devices
btrfs: Do not restrict writes to btrfs devices
block: Add config option to not allow writing to mounted devices
block: Remove blkdev_get_by_*() functions
bcachefs: Convert to bdev_open_by_path()
fs: handle freezing from multiple devices
fs: remove dead check
nilfs2: simplify device handling
fs: streamline thaw_super_locked
ext4: simplify device handling
xfs: simplify device handling
fs: simplify setup_bdev_super() calls
blkdev: comment fs_holder_ops
porting: document block device freeze and thaw changes
fs: remove unused helper
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btrfs has a variety of asynchronous things we do with inodes that can
potentially last until ->put_super, when we shut everything down and
clean up all of our async work. Due to this we need to move
fscrypt_destroy_keyring() to after ->put_super, otherwise we get
warnings about still having active references on the master key.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Link: https://lore.kernel.org/r/20231227171429.9223-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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There is no reason to use a GFP_USER flag for struct super_block allocation
in the alloc_super(). Instead, let's use GFP_KERNEL for that.
>From the memory management perspective, the only difference between
GFP_USER and GFP_KERNEL is that GFP_USER allocations are tied to a cpuset,
while GFP_KERNEL ones are not.
There is no real issue and this is not a candidate to go to the stable,
but let's fix it for a consistency sake.
Cc: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Link: https://lore.kernel.org/r/20231208151022.156273-1-aleksandr.mikhalitsyn@canonical.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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We hold our own active reference and we've checked it above.
Link: https://lore.kernel.org/r/20231127-vfs-super-massage-wait-v1-2-9ab277bfd01a@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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We're currently using two separate helpers wait_born() and wait_dead()
when we can just all do it in a single helper super_load_flags(). We're
also acquiring the lock before we check whether this superblock is even
a viable candidate. If it's already dying we don't even need to bother
with the lock.
Link: https://lore.kernel.org/r/20231127-vfs-super-massage-wait-v1-1-9ab277bfd01a@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Before [1] freezing a filesystems through the block layer only worked
for the main block device as the owning superblock of additional block
devices could not be found. Any filesystem that made use of multiple
block devices would only be freezable via it's main block device.
For example, consider xfs over device mapper with /dev/dm-0 as main
block device and /dev/dm-1 as external log device. Two freeze requests
before [1]:
(1) dmsetup suspend /dev/dm-0 on the main block device
bdev_freeze(dm-0)
-> dm-0->bd_fsfreeze_count++
-> freeze_super(xfs-sb)
The owning superblock is found and the filesystem gets frozen.
Returns 0.
(2) dmsetup suspend /dev/dm-1 on the log device
bdev_freeze(dm-1)
-> dm-1->bd_fsfreeze_count++
The owning superblock isn't found and only the block device freeze
count is incremented. Returns 0.
Two freeze requests after [1]:
(1') dmsetup suspend /dev/dm-0 on the main block device
bdev_freeze(dm-0)
-> dm-0->bd_fsfreeze_count++
-> freeze_super(xfs-sb)
The owning superblock is found and the filesystem gets frozen.
Returns 0.
(2') dmsetup suspend /dev/dm-1 on the log device
bdev_freeze(dm-0)
-> dm-0->bd_fsfreeze_count++
-> freeze_super(xfs-sb)
The owning superblock is found and the filesystem gets frozen.
Returns -EBUSY.
When (2') is called we initiate a freeze from another block device of
the same superblock. So we increment the bd_fsfreeze_count for that
additional block device. But we now also find the owning superblock for
additional block devices and call freeze_super() again which reports
-EBUSY.
This can be reproduced through xfstests via:
mkfs.xfs -f -m crc=1,reflink=1,rmapbt=1, -i sparse=1 -lsize=1g,logdev=/dev/nvme1n1p4 /dev/nvme1n1p3
mkfs.xfs -f -m crc=1,reflink=1,rmapbt=1, -i sparse=1 -lsize=1g,logdev=/dev/nvme1n1p6 /dev/nvme1n1p5
FSTYP=xfs
export TEST_DEV=/dev/nvme1n1p3
export TEST_DIR=/mnt/test
export TEST_LOGDEV=/dev/nvme1n1p4
export SCRATCH_DEV=/dev/nvme1n1p5
export SCRATCH_MNT=/mnt/scratch
export SCRATCH_LOGDEV=/dev/nvme1n1p6
export USE_EXTERNAL=yes
sudo ./check generic/311
Current semantics allow two concurrent freezers: one initiated from
userspace via FREEZE_HOLDER_USERSPACE and one initiated from the kernel
via FREEZE_HOLDER_KERNEL. If there are multiple concurrent freeze
requests from either FREEZE_HOLDER_USERSPACE or FREEZE_HOLDER_KERNEL
-EBUSY is returned.
We need to preserve these semantics because as they are uapi via
FIFREEZE and FITHAW ioctl()s. IOW, freezes don't nest for FIFREEZE and
FITHAW. Other kernels consumers rely on non-nesting freezes as well.
With freezes initiated from the block layer freezes need to nest if the
same superblock is frozen via multiple devices. So we need to start
counting the number of freeze requests.
If FREEZE_MAY_NEST is passed alongside FREEZE_HOLDER_KERNEL or
FREEZE_HOLDER_USERSPACE we allow the caller to nest freeze calls.
To accommodate the old semantics we split the freeze counter into two
counting kernel initiated and userspace initiated freezes separately. We
can then also stop recording FREEZE_HOLDER_* in struct sb_writers.
We also simplify freezing by making all concurrent freezers share a
single active superblock reference count instead of having separate
references for kernel and userspace. I don't see why we would need two
active reference counts. Neither FREEZE_HOLDER_KERNEL nor
FREEZE_HOLDER_USERSPACE can put the active reference as long as they are
concurrent freezers anwyay. That was already true before we allowed
nesting freezes.
Survives various fstests runs with different options including the
reproducer, online scrub, and online repair, fsfreze, and so on. Also
survives blktests.
Link: https://lore.kernel.org/linux-block/87bkccnwxc.fsf@debian-BULLSEYE-live-builder-AMD64
Link: https://lore.kernel.org/r/20231104-vfs-multi-device-freeze-v2-2-5b5b69626eac@kernel.org
Fixes: 288d8706abfc ("bdev: implement freeze and thaw holder operations") [1] # no backport needed
Tested-by: Chandan Babu R <chandanbabu@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Above we call super_lock_excl() which waits until the superblock is
SB_BORN and since SB_BORN is never unset once set this check can never
fire. Plus, we also hold an active reference at this point already so
this superblock can't even be shutdown.
Link: https://lore.kernel.org/r/20231104-vfs-multi-device-freeze-v2-1-5b5b69626eac@kernel.org
Tested-by: Chandan Babu R <chandanbabu@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Add a new out_unlock label to share code that just releases s_umount
and returns an error, and rename and reuse the out label that deactivates
the sb for one more case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231027064001.GA9469@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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There's no need to drop s_umount anymore now that we removed all sources
where s_umount is taken beneath open_mutex or bd_holder_lock.
Link: https://lore.kernel.org/r/20231024-vfs-super-rework-v1-1-37a8aa697148@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The grab_super() helper is now only used by grab_super_dead(). Merge the
two helpers into one.
Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-8-599c19f4faac@kernel.org
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This function is now unused so remove it. One less function that uses
the global superblock list.
Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-6-599c19f4faac@kernel.org
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The old method of implementing block device freeze and thaw operations
required us to rely on get_active_super() to walk the list of all
superblocks on the system to find any superblock that might use the
block device. This is wasteful and not very pleasant overall.
Now that we can finally go straight from block device to owning
superblock things become way simpler.
Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-5-599c19f4faac@kernel.org
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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We have bdev_mark_dead() etc and we're going to move block device
freezing to holder ops in the next patch. Make the naming consistent:
* freeze_bdev() -> bdev_freeze()
* thaw_bdev() -> bdev_thaw()
Also document the return code.
Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-2-599c19f4faac@kernel.org
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Multiple people have balked at the the fact that
super_lock{_shared,_excluse}() return booleans and even if they return
false hold s_umount. So let's change them to only hold s_umount when
true is returned and change the code accordingly.
Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-1-599c19f4faac@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs
Pull overlayfs updates from Amir Goldstein:
- Overlayfs aio cleanups and fixes
Cleanups and minor fixes in preparation for factoring out of
read/write passthrough code.
- Overlayfs lock ordering changes
Hold mnt_writers only throughout copy up instead of a long lived
elevated refcount.
- Add support for nesting overlayfs private xattrs
There are cases where you want to use an overlayfs mount as a
lowerdir for another overlayfs mount. For example, if the system
rootfs is on overlayfs due to composefs, or to make it volatile (via
tmpfs), then you cannot currently store a lowerdir on the rootfs,
because the inner overlayfs will eat all the whiteouts and overlay
xattrs. This means you can't e.g. store on the rootfs a prepared
container image for use with overlayfs.
This adds support for nesting of overlayfs mounts by escaping the
problematic features and unescaping them when exposing to the
overlayfs user.
- Add new mount options for appending lowerdirs
* tag 'ovl-update-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
ovl: add support for appending lowerdirs one by one
ovl: refactor layer parsing helpers
ovl: store and show the user provided lowerdir mount option
ovl: remove unused code in lowerdir param parsing
ovl: Add documentation on nesting of overlayfs mounts
ovl: Add an alternative type of whiteout
ovl: Support escaped overlay.* xattrs
ovl: Add OVL_XATTR_TRUSTED/USER_PREFIX_LEN macros
ovl: Move xattr support to new xattrs.c file
ovl: do not encode lower fh with upper sb_writers held
ovl: do not open/llseek lower file with upper sb_writers held
ovl: reorder ovl_want_write() after ovl_inode_lock()
ovl: split ovl_want_write() into two helpers
ovl: add helper ovl_file_modified()
ovl: protect copying of realinode attributes to ovl inode
ovl: punt write aio completion to workqueue
ovl: propagate IOCB_APPEND flag on writes to realfile
ovl: use simpler function to convert iocb to rw flags
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
- Kemeng Shi has contributed some compation maintenance work in the
series 'Fixes and cleanups to compaction'
- Joel Fernandes has a patchset ('Optimize mremap during mutual
alignment within PMD') which fixes an obscure issue with mremap()'s
pagetable handling during a subsequent exec(), based upon an
implementation which Linus suggested
- More DAMON/DAMOS maintenance and feature work from SeongJae Park i
the following patch series:
mm/damon: misc fixups for documents, comments and its tracepoint
mm/damon: add a tracepoint for damos apply target regions
mm/damon: provide pseudo-moving sum based access rate
mm/damon: implement DAMOS apply intervals
mm/damon/core-test: Fix memory leaks in core-test
mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval
- In the series 'Do not try to access unaccepted memory' Adrian
Hunter provides some fixups for the recently-added 'unaccepted
memory' feature. To increase the feature's checking coverage. 'Plug
a few gaps where RAM is exposed without checking if it is
unaccepted memory'
- In the series 'cleanups for lockless slab shrink' Qi Zheng has done
some maintenance work which is preparation for the lockless slab
shrinking code
- Qi Zheng has redone the earlier (and reverted) attempt to make slab
shrinking lockless in the series 'use refcount+RCU method to
implement lockless slab shrink'
- David Hildenbrand contributes some maintenance work for the rmap
code in the series 'Anon rmap cleanups'
- Kefeng Wang does more folio conversions and some maintenance work
in the migration code. Series 'mm: migrate: more folio conversion
and unification'
- Matthew Wilcox has fixed an issue in the buffer_head code which was
causing long stalls under some heavy memory/IO loads. Some cleanups
were added on the way. Series 'Add and use bdev_getblk()'
- In the series 'Use nth_page() in place of direct struct page
manipulation' Zi Yan has fixed a potential issue with the direct
manipulation of hugetlb page frames
- In the series 'mm: hugetlb: Skip initialization of gigantic tail
struct pages if freed by HVO' has improved our handling of gigantic
pages in the hugetlb vmmemmep optimizaton code. This provides
significant boot time improvements when significant amounts of
gigantic pages are in use
- Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
rationalization and folio conversions in the hugetlb code
- Yin Fengwei has improved mlock()'s handling of large folios in the
series 'support large folio for mlock'
- In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
added statistics for memcg v1 users which are available (and
useful) under memcg v2
- Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
prctl so that userspace may direct the kernel to not automatically
propagate the denial to child processes. The series is named 'MDWE
without inheritance'
- Kefeng Wang has provided the series 'mm: convert numa balancing
functions to use a folio' which does what it says
- In the series 'mm/ksm: add fork-exec support for prctl' Stefan
Roesch makes is possible for a process to propagate KSM treatment
across exec()
- Huang Ying has enhanced memory tiering's calculation of memory
distances. This is used to permit the dax/kmem driver to use 'high
bandwidth memory' in addition to Optane Data Center Persistent
Memory Modules (DCPMM). The series is named 'memory tiering:
calculate abstract distance based on ACPI HMAT'
- In the series 'Smart scanning mode for KSM' Stefan Roesch has
optimized KSM by teaching it to retain and use some historical
information from previous scans
- Yosry Ahmed has fixed some inconsistencies in memcg statistics in
the series 'mm: memcg: fix tracking of pending stats updates
values'
- In the series 'Implement IOCTL to get and optionally clear info
about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap
which permits us to atomically read-then-clear page softdirty
state. This is mainly used by CRIU
- Hugh Dickins contributed the series 'shmem,tmpfs: general
maintenance', a bunch of relatively minor maintenance tweaks to
this code
- Matthew Wilcox has increased the use of the VMA lock over
file-backed page faults in the series 'Handle more faults under the
VMA lock'. Some rationalizations of the fault path became possible
as a result
- In the series 'mm/rmap: convert page_move_anon_rmap() to
folio_move_anon_rmap()' David Hildenbrand has implemented some
cleanups and folio conversions
- In the series 'various improvements to the GUP interface' Lorenzo
Stoakes has simplified and improved the GUP interface with an eye
to providing groundwork for future improvements
- Andrey Konovalov has sent along the series 'kasan: assorted fixes
and improvements' which does those things
- Some page allocator maintenance work from Kemeng Shi in the series
'Two minor cleanups to break_down_buddy_pages'
- In thes series 'New selftest for mm' Breno Leitao has developed
another MM self test which tickles a race we had between madvise()
and page faults
- In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
and an optimization to the core pagecache code
- Nhat Pham has added memcg accounting for hugetlb memory in the
series 'hugetlb memcg accounting'
- Cleanups and rationalizations to the pagemap code from Lorenzo
Stoakes, in the series 'Abstract vma_merge() and split_vma()'
- Audra Mitchell has fixed issues in the procfs page_owner code's new
timestamping feature which was causing some misbehaviours. In the
series 'Fix page_owner's use of free timestamps'
- Lorenzo Stoakes has fixed the handling of new mappings of sealed
files in the series 'permit write-sealed memfd read-only shared
mappings'
- Mike Kravetz has optimized the hugetlb vmemmap optimization in the
series 'Batch hugetlb vmemmap modification operations'
- Some buffer_head folio conversions and cleanups from Matthew Wilcox
in the series 'Finish the create_empty_buffers() transition'
- As a page allocator performance optimization Huang Ying has added
automatic tuning to the allocator's per-cpu-pages feature, in the
series 'mm: PCP high auto-tuning'
- Roman Gushchin has contributed the patchset 'mm: improve
performance of accounted kernel memory allocations' which improves
their performance by ~30% as measured by a micro-benchmark
- folio conversions from Kefeng Wang in the series 'mm: convert page
cpupid functions to folios'
- Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
kmemleak'
- Qi Zheng has improved our handling of memoryless nodes by keeping
them off the allocation fallback list. This is done in the series
'handle memoryless nodes more appropriately'
- khugepaged conversions from Vishal Moola in the series 'Some
khugepaged folio conversions'"
[ bcachefs conflicts with the dynamically allocated shrinkers have been
resolved as per Stephen Rothwell in
https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/
with help from Qi Zheng.
The clone3 test filtering conflict was half-arsed by yours truly ]
* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
mm/damon/sysfs: update monitoring target regions for online input commit
mm/damon/sysfs: remove requested targets when online-commit inputs
selftests: add a sanity check for zswap
Documentation: maple_tree: fix word spelling error
mm/vmalloc: fix the unchecked dereference warning in vread_iter()
zswap: export compression failure stats
Documentation: ubsan: drop "the" from article title
mempolicy: migration attempt to match interleave nodes
mempolicy: mmap_lock is not needed while migrating folios
mempolicy: alloc_pages_mpol() for NUMA policy without vma
mm: add page_rmappable_folio() wrapper
mempolicy: remove confusing MPOL_MF_LAZY dead code
mempolicy: mpol_shared_policy_init() without pseudo-vma
mempolicy trivia: use pgoff_t in shared mempolicy tree
mempolicy trivia: slightly more consistent naming
mempolicy trivia: delete those ancient pr_debug()s
mempolicy: fix migrate_pages(2) syscall return nr_failed
kernfs: drop shared NUMA mempolicy hooks
hugetlbfs: drop shared NUMA mempolicy pretence
mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
...
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We want to protect concurrent updates of ovl inode size and mtime
(i.e. ovl_copyattr()) from aio completion context.
Punt write aio completion to a workqueue so that we can protect
ovl_copyattr() with a spinlock.
Export sb_init_dio_done_wq(), so that overlayfs can use its own
dio workqueue to punt aio completions.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/8620dfd3-372d-4ae0-aa3f-2fe97dda1bca@kernel.dk/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
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With recent block level changes we should never be in a situation where
we hold disk->open_mutex when calling into these helpers. So assert that
in the code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231017184823.1383356-6-hch@lst.de
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The implementation of bdev holder operations such as fs_bdev_mark_dead()
and fs_bdev_sync() grab sb->s_umount semaphore under
bdev->bd_holder_lock. This is problematic because it leads to
disk->open_mutex -> sb->s_umount lock ordering which is counterintuitive
(usually we grab higher level (e.g. filesystem) locks first and lower
level (e.g. block layer) locks later) and indeed makes lockdep complain
about possible locking cycles whenever we open a block device while
holding sb->s_umount semaphore. Implement a function
bdev_super_lock_shared() which safely transitions from holding
bdev->bd_holder_lock to holding sb->s_umount on alive superblock without
introducing the problematic lock dependency. We use this function
fs_bdev_sync() and fs_bdev_mark_dead().
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231018152924.3858-1-jack@suse.cz
Link: https://lore.kernel.org/r/20231017184823.1383356-1-hch@lst.de
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Convert mount code to use bdev_open_by_dev() and propagate the handle
around to bdev_release().
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-19-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>
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|
Now there are no readers of shrinker_rwsem, so we can simply replace it
with mutex lock.
[akpm@linux-foundation.org: update the fix to alloc_shrinker_info()]
Link: https://lkml.kernel.org/r/20230911094444.68966-46-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In preparation for implementing lockless slab shrink, use new APIs to
dynamically allocate the s_shrink, so that it can be freed asynchronously
via RCU. Then it doesn't need to wait for RCU read-side critical section
when releasing the struct super_block.
Link: https://lkml.kernel.org/r/20230911094444.68966-39-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
They will be used for mtd devices as well.
Acked-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230829-vfs-super-mtd-v1-1-fecb572e5df3@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Pull block updates from Jens Axboe:
"Pretty quiet round for this release. This contains:
- Add support for zoned storage to ublk (Andreas, Ming)
- Series improving performance for drivers that mark themselves as
needing a blocking context for issue (Bart)
- Cleanup the flush logic (Chengming)
- sed opal keyring support (Greg)
- Fixes and improvements to the integrity support (Jinyoung)
- Add some exports for bcachefs that we can hopefully delete again in
the future (Kent)
- deadline throttling fix (Zhiguo)
- Series allowing building the kernel without buffer_head support
(Christoph)
- Sanitize the bio page adding flow (Christoph)
- Write back cache fixes (Christoph)
- MD updates via Song:
- Fix perf regression for raid0 large sequential writes (Jan)
- Fix split bio iostat for raid0 (David)
- Various raid1 fixes (Heinz, Xueshi)
- raid6test build fixes (WANG)
- Deprecate bitmap file support (Christoph)
- Fix deadlock with md sync thread (Yu)
- Refactor md io accounting (Yu)
- Various non-urgent fixes (Li, Yu, Jack)
- Various fixes and cleanups (Arnd, Azeem, Chengming, Damien, Li,
Ming, Nitesh, Ruan, Tejun, Thomas, Xu)"
* tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux: (113 commits)
block: use strscpy() to instead of strncpy()
block: sed-opal: keyring support for SED keys
block: sed-opal: Implement IOC_OPAL_REVERT_LSP
block: sed-opal: Implement IOC_OPAL_DISCOVERY
blk-mq: prealloc tags when increase tagset nr_hw_queues
blk-mq: delete redundant tagset map update when fallback
blk-mq: fix tags leak when shrink nr_hw_queues
ublk: zoned: support REQ_OP_ZONE_RESET_ALL
md: raid0: account for split bio in iostat accounting
md/raid0: Fix performance regression for large sequential writes
md/raid0: Factor out helper for mapping and submitting a bio
md raid1: allow writebehind to work on any leg device set WriteMostly
md/raid1: hold the barrier until handle_read_error() finishes
md/raid1: free the r1bio before waiting for blocked rdev
md/raid1: call free_r1bio() before allow_barrier() in raid_end_bio_io()
blk-cgroup: Fix NULL deref caused by blkg_policy_data being installed before init
drivers/rnbd: restore sysfs interface to rnbd-client
md/raid5-cache: fix null-ptr-deref for r5l_flush_stripe_to_raid()
raid6: test: only check for Altivec if building on powerpc hosts
raid6: test: make sure all intermediate and artifact files are .gitignored
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull superblock fixes from Christian Brauner:
"Two follow-up fixes for the super work this cycle:
- Move a misplaced lockep assertion before we potentially free the
object containing the lock.
- Ensure that filesystems which match superblocks in sget{_fc}()
based on sb->s_fs_info are guaranteed to see a valid sb->s_fs_info
as long as a superblock still appears on the filesystem type's
superblock list.
What we want as a proper solution for next cycle is to split
sb->free_sb() out of sb->kill_sb() so that we can simply call
kill_super_notify() after sb->kill_sb() but before sb->free_sb().
Currently, this is lumped together in sb->kill_sb()"
* tag 'v6.6-vfs.super.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
super: ensure valid info
super: move lockdep assert
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For keyed filesystems that recycle superblocks based on s_fs_info or
information contained therein s_fs_info must be kept as long as the
superblock is on the filesystem type super list. This isn't guaranteed
as s_fs_info will be freed latest in sb->kill_sb().
The fix is simply to perform notification and list removal in
kill_anon_super(). Any filesystem needs to free s_fs_info after they
call the kill_*() helpers. If they don't they risk use-after-free right
now so fixing it here is guaranteed that s_fs_info remain valid.
For block backed filesystems notifying in pass sb->kill_sb() in
deactivate_locked_super() remains unproblematic and is required because
multiple other block devices can be shut down after kill_block_super()
has been called from a filesystem's sb->kill_sb() handler. For example,
ext4 and xfs close additional devices. Block based filesystems don't
depend on s_fs_info (btrfs does use s_fs_info but also uses
kill_anon_super() and not kill_block_super().).
Sorry for that braino. Goal should be to unify this behavior during this
cycle obviously. But let's please do a simple bugfix now.
Fixes: 2c18a63b760a ("super: wait until we passed kill super")
Fixes: syzbot+5b64180f8d9e39d3f061@syzkaller.appspotmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reported-by: syzbot+5b64180f8d9e39d3f061@syzkaller.appspotmail.com
Message-Id: <20230828-vfs-super-fixes-v1-2-b37a4a04a88f@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
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Fix braino and move the lockdep assertion after put_super() otherwise we
risk a use-after-free.
Fixes: 2c18a63b760a ("super: wait until we passed kill super")
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <20230828-vfs-super-fixes-v1-1-b37a4a04a88f@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull superblock updates from Christian Brauner:
"This contains the super rework that was ready for this cycle. The
first part changes the order of how we open block devices and allocate
superblocks, contains various cleanups, simplifications, and a new
mechanism to wait on superblock state changes.
This unblocks work to ultimately limit the number of writers to a
block device. Jan has already scheduled follow-up work that will be
ready for v6.7 and allows us to restrict the number of writers to a
given block device. That series builds on this work right here.
The second part contains filesystem freezing updates.
Overview:
The generic superblock changes are rougly organized as follows
(ignoring additional minor cleanups):
(1) Removal of the bd_super member from struct block_device.
This was a very odd back pointer to struct super_block with
unclear rules. For all relevant places we have other means to get
the same information so just get rid of this.
(2) Simplify rules for superblock cleanup.
Roughly, everything that is allocated during fs_context
initialization and that's stored in fs_context->s_fs_info needs
to be cleaned up by the fs_context->free() implementation before
the superblock allocation function has been called successfully.
After sget_fc() returned fs_context->s_fs_info has been
transferred to sb->s_fs_info at which point sb->kill_sb() if
fully responsible for cleanup. Adhering to these rules means that
cleanup of sb->s_fs_info in fill_super() is to be avoided as it's
brittle and inconsistent.
Cleanup shouldn't be duplicated between sb->put_super() as
sb->put_super() is only called if sb->s_root has been set aka
when the filesystem has been successfully born (SB_BORN). That
complexity should be avoided.
This also means that block devices are to be closed in
sb->kill_sb() instead of sb->put_super(). More details in the
lower section.
(3) Make it possible to lookup or create a superblock before opening
block devices
There's a subtle dependency on (2) as some filesystems did rely
on fill_super() to be called in order to correctly clean up
sb->s_fs_info. All these filesystems have been fixed.
(4) Switch most filesystem to follow the same logic as the generic
mount code now does as outlined in (3).
(5) Use the superblock as the holder of the block device. We can now
easily go back from block device to owning superblock.
(6) Export and extend the generic fs_holder_ops and use them as
holder ops everywhere and remove the filesystem specific holder
ops.
(7) Call from the block layer up into the filesystem layer when the
block device is removed, allowing to shut down the filesystem
without risk of deadlocks.
(8) Get rid of get_super().
We can now easily go back from the block device to owning
superblock and can call up from the block layer into the
filesystem layer when the device is removed. So no need to wade
through all registered superblock to find the owning superblock
anymore"
Link: https://lore.kernel.org/lkml/20230824-prall-intakt-95dbffdee4a0@brauner/
* tag 'v6.6-vfs.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (47 commits)
super: use higher-level helper for {freeze,thaw}
super: wait until we passed kill super
super: wait for nascent superblocks
super: make locking naming consistent
super: use locking helpers
fs: simplify invalidate_inodes
fs: remove get_super
block: call into the file system for ioctl BLKFLSBUF
block: call into the file system for bdev_mark_dead
block: consolidate __invalidate_device and fsync_bdev
block: drop the "busy inodes on changed media" log message
dasd: also call __invalidate_device when setting the device offline
amiflop: don't call fsync_bdev in FDFMTBEG
floppy: call disk_force_media_change when changing the format
block: simplify the disk_force_media_change interface
nbd: call blk_mark_disk_dead in nbd_clear_sock_ioctl
xfs use fs_holder_ops for the log and RT devices
xfs: drop s_umount over opening the log and RT devices
ext4: use fs_holder_ops for the log device
ext4: drop s_umount over opening the log device
...
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ssh://gitolite.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull filesystem freezing updates from Darrick Wong:
New code for 6.6:
* Allow the kernel to initiate a freeze of a filesystem. The kernel
and userspace can both hold a freeze on a filesystem at the same
time; the freeze is not lifted until /both/ holders lift it. This
will enable us to fix a longstanding bug in XFS online fsck.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Message-Id: <20230822182604.GB11286@frogsfrogsfrogs>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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It's not necessary to use low-level locking helpers here. Use the
higher-level locking helpers and log if the superblock is dying. Since
the caller is assumed to already hold an active reference it isn't
possible to observe a dying superblock.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
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Recent rework moved block device closing out of sb->put_super() and into
sb->kill_sb() to avoid deadlocks as s_umount is held in put_super() and
blkdev_put() can end up taking s_umount again.
That means we need to move the removal of the superblock from @fs_supers
out of generic_shutdown_super() and into deactivate_locked_super() to
ensure that concurrent mounters don't fail to open block devices that
are still in use because blkdev_put() in sb->kill_sb() hasn't been
called yet.
We can now do this as we can make iterators through @fs_super and
@super_blocks wait without holding s_umount. Concurrent mounts will wait
until a dying superblock is fully dead so until sb->kill_sb() has been
called and SB_DEAD been set. Concurrent iterators can already discard
any SB_DYING superblock.
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230818-vfs-super-fixes-v3-v3-4-9f0b1876e46b@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Recent patches experiment with making it possible to allocate a new
superblock before opening the relevant block device. Naturally this has
intricate side-effects that we get to learn about while developing this.
Superblock allocators such as sget{_fc}() return with s_umount of the
new superblock held and lock ordering currently requires that block
level locks such as bdev_lock and open_mutex rank above s_umount.
Before aca740cecbe5 ("fs: open block device after superblock creation")
ordering was guaranteed to be correct as block devices were opened prior
to superblock allocation and thus s_umount wasn't held. But now s_umount
must be dropped before opening block devices to avoid locking
violations.
This has consequences. The main one being that iterators over
@super_blocks and @fs_supers that grab a temporary reference to the
superblock can now also grab s_umount before the caller has managed to
open block devices and called fill_super(). So whereas before such
iterators or concurrent mounts would have simply slept on s_umount until
SB_BORN was set or the superblock was discard due to initalization
failure they can now needlessly spin through sget{_fc}().
If the caller is sleeping on bdev_lock or open_mutex one caller waiting
on SB_BORN will always spin somewhere and potentially this can go on for
quite a while.
It should be possible to drop s_umount while allowing iterators to wait
on a nascent superblock to either be born or discarded. This patch
implements a wait_var_event() mechanism allowing iterators to sleep
until they are woken when the superblock is born or discarded.
This also allows us to avoid relooping through @fs_supers and
@super_blocks if a superblock isn't yet born or dying.
Link: aca740cecbe5 ("fs: open block device after superblock creation")
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230818-vfs-super-fixes-v3-v3-3-9f0b1876e46b@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Make the naming consistent with the earlier introduced
super_lock_{read,write}() helpers.
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230818-vfs-super-fixes-v3-v3-2-9f0b1876e46b@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Replace the open-coded {down,up}_{read,write}() calls with simple
wrappers. Follow-up patches will benefit from this as well.
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230818-vfs-super-fixes-v3-v3-1-9f0b1876e46b@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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kill_dirty has always been true for a long time, so hard code it and
remove the unused return value.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-18-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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get_super is unused now, remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-17-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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BLKFLSBUF is a historic ioctl that is called on a file handle to a
block device and syncs either the file system mounted on that block
device if there is one, or otherwise the just the data on the block
device.
Replace the get_super based syncing with a holder operation to remove
the last usage of get_super, and to also support syncing the file system
if the block device is not the main block device stored in s_dev.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-16-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Combine the newly merged bdev_mark_dead helper with the existing
mark_dead holder operation so that all operations that invalidate
a device that is dead or being removed now go through the holder
ops. This allows file systems to explicitly shutdown either ASAP
(for a surprise removal) or after writing back data (for an orderly
removal), and do so not only for the main device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-15-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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We currently have two interfaces that take a block_devices and the find
a mounted file systems to flush or invaldidate data on it. Both are a
bit problematic because they only work for the "main" block devices
that is used as s_dev for the super_block, and because they don't call
into the file system at all.
Merge the two into a new bdev_mark_dead helper that does both the
syncing and invalidation and which is properly documented. This is
in preparation of merging the functionality into the ->mark_dead
holder operation so that it will work on additional block devices
used by a file systems and give us a single entry point for invalidation
of dead devices or media.
Note that a single standalone fsync_bdev call for an obscure ioctl
remains for now, but that one will also be deal with in a bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-14-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Summary
=======
This introduces FSCONFIG_CMD_CREATE_EXCL which will allows userspace to
implement something like mount -t ext4 --exclusive /dev/sda /B which
fails if a superblock for the requested filesystem does already exist:
Before this patch
-----------------
$ sudo ./move-mount -f xfs -o source=/dev/sda4 /A
Requesting filesystem type xfs
Mount options requested: source=/dev/sda4
Attaching mount at /A
Moving single attached mount
Setting key(source) with val(/dev/sda4)
$ sudo ./move-mount -f xfs -o source=/dev/sda4 /B
Requesting filesystem type xfs
Mount options requested: source=/dev/sda4
Attaching mount at /B
Moving single attached mount
Setting key(source) with val(/dev/sda4)
After this patch with --exclusive as a switch for FSCONFIG_CMD_CREATE_EXCL
--------------------------------------------------------------------------
$ sudo ./move-mount -f xfs --exclusive -o source=/dev/sda4 /A
Requesting filesystem type xfs
Request exclusive superblock creation
Mount options requested: source=/dev/sda4
Attaching mount at /A
Moving single attached mount
Setting key(source) with val(/dev/sda4)
$ sudo ./move-mount -f xfs --exclusive -o source=/dev/sda4 /B
Requesting filesystem type xfs
Request exclusive superblock creation
Mount options requested: source=/dev/sda4
Attaching mount at /B
Moving single attached mount
Setting key(source) with val(/dev/sda4)
Device or resource busy | move-mount.c: 300: do_fsconfig: i xfs: reusing existing filesystem not allowed
Details
=======
As mentioned on the list (cf. [1]-[3]) mount requests like
mount -t ext4 /dev/sda /A are ambigous for userspace. Either a new
superblock has been created and mounted or an existing superblock has
been reused and a bind-mount has been created.
This becomes clear in the following example where two processes create
the same mount for the same block device:
P1 P2
fd_fs = fsopen("ext4"); fd_fs = fsopen("ext4");
fsconfig(fd_fs, FSCONFIG_SET_STRING, "source", "/dev/sda"); fsconfig(fd_fs, FSCONFIG_SET_STRING, "source", "/dev/sda");
fsconfig(fd_fs, FSCONFIG_SET_STRING, "dax", "always"); fsconfig(fd_fs, FSCONFIG_SET_STRING, "resuid", "1000");
// wins and creates superblock
fsconfig(fd_fs, FSCONFIG_CMD_CREATE, ...)
// finds compatible superblock of P1
// spins until P1 sets SB_BORN and grabs a reference
fsconfig(fd_fs, FSCONFIG_CMD_CREATE, ...)
fd_mnt1 = fsmount(fd_fs); fd_mnt2 = fsmount(fd_fs);
move_mount(fd_mnt1, "/A") move_mount(fd_mnt2, "/B")
Not just does P2 get a bind-mount but the mount options that P2
requestes are silently ignored. The VFS itself doesn't, can't and
shouldn't enforce filesystem specific mount option compatibility. It
only enforces incompatibility for read-only <-> read-write transitions:
mount -t ext4 /dev/sda /A
mount -t ext4 -o ro /dev/sda /B
The read-only request will fail with EBUSY as the VFS can't just
silently transition a superblock from read-write to read-only or vica
versa without risking security issues.
To userspace this silent superblock reuse can become a security issue in
because there is currently no straightforward way for userspace to know
that they did indeed manage to create a new superblock and didn't just
reuse an existing one.
This adds a new FSCONFIG_CMD_CREATE_EXCL command to fsconfig() that
returns EBUSY if an existing superblock would be reused. Userspace that
needs to be sure that it did create a new superblock with the requested
mount options can request superblock creation using this command. If the
command succeeds they can be sure that they did create a new superblock
with the requested mount options.
This requires the new mount api. With the old mount api it would be
necessary to plumb this through every legacy filesystem's
file_system_type->mount() method. If they want this feature they are
most welcome to switch to the new mount api.
Following is an analysis of the effect of FSCONFIG_CMD_CREATE_EXCL on
each high-level superblock creation helper:
(1) get_tree_nodev()
Always allocate new superblock. Hence, FSCONFIG_CMD_CREATE and
FSCONFIG_CMD_CREATE_EXCL are equivalent.
The binderfs or overlayfs filesystems are examples.
(4) get_tree_keyed()
Finds an existing superblock based on sb->s_fs_info. Hence,
FSCONFIG_CMD_CREATE would reuse an existing superblock whereas
FSCONFIG_CMD_CREATE_EXCL would reject it with EBUSY.
The mqueue or nfsd filesystems are examples.
(2) get_tree_bdev()
This effectively works like get_tree_keyed().
The ext4 or xfs filesystems are examples.
(3) get_tree_single()
Only one superblock of this filesystem type can ever exist.
Hence, FSCONFIG_CMD_CREATE would reuse an existing superblock
whereas FSCONFIG_CMD_CREATE_EXCL would reject it with EBUSY.
The securityfs or configfs filesystems are examples.
Note that some single-instance filesystems never destroy the
superblock once it has been created during the first mount. For
example, if securityfs has been mounted at least onces then the
created superblock will never be destroyed again as long as there is
still an LSM making use it. Consequently, even if securityfs is
unmounted and the superblock seemingly destroyed it really isn't
which means that FSCONFIG_CMD_CREATE_EXCL will continue rejecting
reusing an existing superblock.
This is acceptable thugh since special purpose filesystems such as
this shouldn't have a need to use FSCONFIG_CMD_CREATE_EXCL anyway
and if they do it's probably to make sure that mount options aren't
ignored.
Following is an analysis of the effect of FSCONFIG_CMD_CREATE_EXCL on
filesystems that make use of the low-level sget_fc() helper directly.
They're all effectively variants on get_tree_keyed(), get_tree_bdev(),
or get_tree_nodev():
(5) mtd_get_sb()
Similar logic to get_tree_keyed().
(6) afs_get_tree()
Similar logic to get_tree_keyed().
(7) ceph_get_tree()
Similar logic to get_tree_keyed().
Already explicitly allows forcing the allocation of a new superblock
via CEPH_OPT_NOSHARE. This turns it into get_tree_nodev().
(8) fuse_get_tree_submount()
Similar logic to get_tree_nodev().
(9) fuse_get_tree()
Forces reuse of existing FUSE superblock.
Forces reuse of existing superblock if passed in file refers to an
existing FUSE connection.
If FSCONFIG_CMD_CREATE_EXCL is specified together with an fd
referring to an existing FUSE connections this would cause the
superblock reusal to fail. If reusing is the intent then
FSCONFIG_CMD_CREATE_EXCL shouldn't be specified.
(10) fuse_get_tree()
-> get_tree_nodev()
Same logic as in get_tree_nodev().
(11) fuse_get_tree()
-> get_tree_bdev()
Same logic as in get_tree_bdev().
(12) virtio_fs_get_tree()
Same logic as get_tree_keyed().
(13) gfs2_meta_get_tree()
Forces reuse of existing gfs2 superblock.
Mounting gfs2meta enforces that a gf2s superblock must already
exist. If not, it will error out. Consequently, mounting gfs2meta
with FSCONFIG_CMD_CREATE_EXCL would always fail. If reusing is the
intent then FSCONFIG_CMD_CREATE_EXCL shouldn't be specified.
(14) kernfs_get_tree()
Similar logic to get_tree_keyed().
(15) nfs_get_tree_common()
Similar logic to get_tree_keyed().
Already explicitly allows forcing the allocation of a new superblock
via NFS_MOUNT_UNSHARED. This effectively turns it into
get_tree_nodev().
Link: [1] https://lore.kernel.org/linux-block/20230704-fasching-wertarbeit-7c6ffb01c83d@brauner
Link: [2] https://lore.kernel.org/linux-block/20230705-pumpwerk-vielversprechend-a4b1fd947b65@brauner
Link: [3] https://lore.kernel.org/linux-fsdevel/20230725-einnahmen-warnschilder-17779aec0a97@brauner
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Message-Id: <20230802-vfs-super-exclusive-v2-4-95dc4e41b870@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The get_tree_single_reconf() helper isn't used anywhere. Remove it.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Message-Id: <20230802-vfs-super-exclusive-v2-1-95dc4e41b870@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Export fs_holder_ops so that file systems that open additional block
devices can use it as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230802154131.2221419-9-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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fs_mark_dead currently uses get_super to find the superblock for the
block device that is going away. This means it is limited to the
main device stored in sb->s_dev, leading to a lot of code duplication
for file systems that can use multiple block devices.
Now that the holder for all block devices used by file systems is set
to the super_block, we can instead look at that holder and then check
if the file system is born and active, so do that instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230802154131.2221419-8-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The file system type is not a very useful holder as it doesn't allow us
to go back to the actual file system instance. Pass the super_block instead
which is useful when passed back to the file system driver.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230802154131.2221419-7-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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We'll want to use setup_bdev_super instead of duplicating it in nilfs2.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230802154131.2221419-2-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Currently get_tree_bdev and mount_bdev open the block device before
committing to allocating a super block. That creates problems for
restricting the number of writers to a device, and also leads to a
unusual and not very helpful holder (the fs_type).
Reorganize the super block code to first look whether the superblock for
a particular device does already exist and open the block device only if
it doesn't.
[hch: port to before the bdev_handle changes,
duplicate the bdev read-only check from blkdev_get_by_path,
extend the fsfree_mutex coverage to protect against freezes,
fix an open bdev leak when the bdev is frozen,
use the bdev local variable more,
rename the s variable to sb to be more descriptive]
[brauner: remove references to mounts as they're mostly irrelevant]
[brauner & hch: fold fixes for romfs and cramfs for
syzbot+2faac0423fdc9692822b@syzkaller.appspotmail.com]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Message-Id: <20230724175145.201318-1-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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bdev->bd_super is unused now, remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230807112625.652089-5-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Fold emergency_thaw_bdev into it's only caller, to prepare for buffer.c
to be built only when buffer_head support is enabled.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230801172201.1923299-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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