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>
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Merge tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux
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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Merge tag 'v6.6-vfs.super.fixes' of 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
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: 2c18a63b76 ("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>
Fix braino and move the lockdep assertion after put_super() otherwise we
risk a use-after-free.
Fixes: 2c18a63b76 ("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>
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Merge tag 'v6.6-vfs.super' of 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
...
* 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>
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Merge tag 'vfs-6.6-merge-2' of 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>
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>
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 aca740cecb ("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: aca740cecb ("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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Jan Kara suggested that when one thread is in the middle of freezing a
filesystem, another thread trying to freeze the same fs but with a
different freeze_holder should wait until the freezer reaches either end
state (UNFROZEN or COMPLETE) instead of returning EBUSY immediately.
Neither caller can do anything sensible with this race other than retry
but they cannot really distinguish EBUSY as in "some other holder of the
same type has the sb already frozen" from "freezing raced with holder of
a different type".
Plumb in the extra code needed to wait for the fs freezer to reach an
end state and try the freeze again.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Userspace can freeze a filesystem using the FIFREEZE ioctl or by
suspending the block device; this state persists until userspace thaws
the filesystem with the FITHAW ioctl or resuming the block device.
Since commit 18e9e5104f ("Introduce freeze_super and thaw_super for
the fsfreeze ioctl") we only allow the first freeze command to succeed.
The kernel may decide that it is necessary to freeze a filesystem for
its own internal purposes, such as suspends in progress, filesystem fsck
activities, or quiescing a device prior to removal. Userspace thaw
commands must never break a kernel freeze, and kernel thaw commands
shouldn't undo userspace's freeze command.
Introduce a couple of freeze holder flags and wire it into the
sb_writers state. One kernel and one userspace freeze are allowed to
coexist at the same time; the filesystem will not thaw until both are
lifted.
I wonder if the f2fs/gfs2 code should be using a kernel freeze here, but
for now we'll use FREEZE_HOLDER_USERSPACE to preserve existing
behaviors.
Cc: mcgrof@kernel.org
Cc: jack@suse.cz
Cc: hch@infradead.org
Cc: ruansy.fnst@fujitsu.com
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
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Merge tag 'fs_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull misc filesystem updates from Jan Kara:
- Rewrite kmap_local() handling in ext2
- Convert ext2 direct IO path to iomap (with some infrastructure tweaks
associated with that)
- Convert two boilerplate licenses in udf to SPDX identifiers
- Other small udf, ext2, and quota fixes and cleanups
* tag 'fs_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
udf: Fix uninitialized array access for some pathnames
ext2: Drop fragment support
quota: fix warning in dqgrab()
quota: Properly disable quotas when add_dquot_ref() fails
fs: udf: udftime: Replace LGPL boilerplate with SPDX identifier
fs: udf: Replace GPL 2.0 boilerplate license notice with SPDX identifier
fs: Drop wait_unfrozen wait queue
ext2_find_entry()/ext2_dotdot(): callers don't need page_addr anymore
ext2_{set_link,delete_entry}(): don't bother with page_addr
ext2_put_page(): accept any pointer within the page
ext2_get_page(): saner type
ext2: use offset_in_page() instead of open-coding it as subtraction
ext2_rename(): set_link and delete_entry may fail
ext2: Add direct-io trace points
ext2: Move direct-io to use iomap
ext2: Use generic_buffers_fsync() implementation
ext4: Use generic_buffers_fsync_noflush() implementation
fs/buffer.c: Add generic_buffers_fsync*() implementation
ext2/dax: Fix ext2_setsize when len is page aligned
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Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe pull request via Keith:
- Various cleanups all around (Irvin, Chaitanya, Christophe)
- Better struct packing (Christophe JAILLET)
- Reduce controller error logs for optional commands (Keith)
- Support for >=64KiB block sizes (Daniel Gomez)
- Fabrics fixes and code organization (Max, Chaitanya, Daniel
Wagner)
- bcache updates via Coly:
- Fix a race at init time (Mingzhe Zou)
- Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye)
- use page pinning in the block layer for dio (David)
- convert old block dio code to page pinning (David, Christoph)
- cleanups for pktcdvd (Andy)
- cleanups for rnbd (Guoqing)
- use the unchecked __bio_add_page() for the initial single page
additions (Johannes)
- fix overflows in the Amiga partition handling code (Michael)
- improve mq-deadline zoned device support (Bart)
- keep passthrough requests out of the IO schedulers (Christoph, Ming)
- improve support for flush requests, making them less special to deal
with (Christoph)
- add bdev holder ops and shutdown methods (Christoph)
- fix the name_to_dev_t() situation and use cases (Christoph)
- decouple the block open flags from fmode_t (Christoph)
- ublk updates and cleanups, including adding user copy support (Ming)
- BFQ sanity checking (Bart)
- convert brd from radix to xarray (Pankaj)
- constify various structures (Thomas, Ivan)
- more fine grained persistent reservation ioctl capability checks
(Jingbo)
- misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan,
Jordy, Li, Min, Yu, Zhong, Waiman)
* tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits)
scsi/sg: don't grab scsi host module reference
ext4: Fix warning in blkdev_put()
block: don't return -EINVAL for not found names in devt_from_devname
cdrom: Fix spectre-v1 gadget
block: Improve kernel-doc headers
blk-mq: don't insert passthrough request into sw queue
bsg: make bsg_class a static const structure
ublk: make ublk_chr_class a static const structure
aoe: make aoe_class a static const structure
block/rnbd: make all 'class' structures const
block: fix the exclusive open mask in disk_scan_partitions
block: add overflow checks for Amiga partition support
block: change all __u32 annotations to __be32 in affs_hardblocks.h
block: fix signed int overflow in Amiga partition support
block: add capacity validation in bdev_add_partition()
block: fine-granular CAP_SYS_ADMIN for Persistent Reservation
block: disallow Persistent Reservation on partitions
reiserfs: fix blkdev_put() warning from release_journal_dev()
block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions()
block: document the holder argument to blkdev_get_by_path
...
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Merge tag 'v6.5/vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"Miscellaneous features, cleanups, and fixes for vfs and individual fs
Features:
- Use mode 0600 for file created by cachefilesd so it can be run by
unprivileged users. This aligns them with directories which are
already created with mode 0700 by cachefilesd
- Reorder a few members in struct file to prevent some false sharing
scenarios
- Indicate that an eventfd is used a semaphore in the eventfd's
fdinfo procfs file
- Add a missing uapi header for eventfd exposing relevant uapi
defines
- Let the VFS protect transitions of a superblock from read-only to
read-write in addition to the protection it already provides for
transitions from read-write to read-only. Protecting read-only to
read-write transitions allows filesystems such as ext4 to perform
internal writes, keeping writers away until the transition is
completed
Cleanups:
- Arnd removed the architecture specific arch_report_meminfo()
prototypes and added a generic one into procfs.h. Note, we got a
report about a warning in amdpgpu codepaths that suggested this was
bisectable to this change but we concluded it was a false positive
- Remove unused parameters from split_fs_names()
- Rename put_and_unmap_page() to unmap_and_put_page() to let the name
reflect the order of the cleanup operation that has to unmap before
the actual put
- Unexport buffer_check_dirty_writeback() as it is not used outside
of block device aops
- Stop allocating aio rings from highmem
- Protecting read-{only,write} transitions in the VFS used open-coded
barriers in various places. Replace them with proper little helpers
and document both the helpers and all barrier interactions involved
when transitioning between read-{only,write} states
- Use flexible array members in old readdir codepaths
Fixes:
- Use the correct type __poll_t for epoll and eventfd
- Replace all deprecated strlcpy() invocations, whose return value
isn't checked with an equivalent strscpy() call
- Fix some kernel-doc warnings in fs/open.c
- Reduce the stack usage in jffs2's xattr codepaths finally getting
rid of this: fs/jffs2/xattr.c:887:1: error: the frame size of 1088
bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
royally annoying compilation warning
- Use __FMODE_NONOTIFY instead of FMODE_NONOTIFY where an int and not
fmode_t is required to avoid fmode_t to integer degradation
warnings
- Create coredumps with O_WRONLY instead of O_RDWR. There's a long
explanation in that commit how O_RDWR is actually a bug which we
found out with the help of Linus and git archeology
- Fix "no previous prototype" warnings in the pipe codepaths
- Add overflow calculations for remap_verify_area() as a signed
addition overflow could be triggered in xfstests
- Fix a null pointer dereference in sysv
- Use an unsigned variable for length calculations in jfs avoiding
compilation warnings with gcc 13
- Fix a dangling pipe pointer in the watch queue codepath
- The legacy mount option parser provided as a fallback by the VFS
for filesystems not yet converted to the new mount api did prefix
the generated mount option string with a leading ',' causing issues
for some filesystems
- Fix a repeated word in a comment in fs.h
- autofs: Update the ctime when mtime is updated as mandated by
POSIX"
* tag 'v6.5/vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits)
readdir: Replace one-element arrays with flexible-array members
fs: Provide helpers for manipulating sb->s_readonly_remount
fs: Protect reconfiguration of sb read-write from racing writes
eventfd: add a uapi header for eventfd userspace APIs
autofs: set ctime as well when mtime changes on a dir
eventfd: show the EFD_SEMAPHORE flag in fdinfo
fs/aio: Stop allocating aio rings from HIGHMEM
fs: Fix comment typo
fs: unexport buffer_check_dirty_writeback
fs: avoid empty option when generating legacy mount string
watch_queue: prevent dangling pipe pointer
fs.h: Optimize file struct to prevent false sharing
highmem: Rename put_and_unmap_page() to unmap_and_put_page()
cachefiles: Allow the cache to be non-root
init: remove unused names parameter in split_fs_names()
jfs: Use unsigned variable for length calculations
fs/sysv: Null check to prevent null-ptr-deref bug
fs: use UB-safe check for signed addition overflow in remap_verify_area
procfs: consolidate arch_report_meminfo declaration
fs: pipe: reveal missing function protoypes
...
Provide helpers to set and clear sb->s_readonly_remount including
appropriate memory barriers. Also use this opportunity to document what
the barriers pair with and why they are needed.
Suggested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Message-Id: <20230620112832.5158-1-jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Patch series "revert shrinker_srcu related changes".
This patch (of 7):
This reverts commit cf2e309ebc.
Kernel test robot reports -88.8% regression in stress-ng.ramfs.ops_per_sec
test case [1], which is caused by commit f95bdb700b ("mm: vmscan: make
global slab shrink lockless"). The root cause is that SRCU has to be
careful to not frequently check for SRCU read-side critical section exits.
Therefore, even if no one is currently in the SRCU read-side critical
section, synchronize_srcu() cannot return quickly. That's why
unregister_shrinker() has become slower.
After discussion, we will try to use the refcount+RCU method [2] proposed
by Dave Chinner to continue to re-implement the lockless slab shrink. So
revert the shrinker_mutex back to shrinker_rwsem first.
[1]. https://lore.kernel.org/lkml/202305230837.db2c233f-yujie.liu@intel.com/
[2]. https://lore.kernel.org/lkml/ZIJhou1d55d4H1s0@dread.disaster.area/
Link: https://lkml.kernel.org/r/20230609081518.3039120-1-qi.zheng@linux.dev
Link: https://lkml.kernel.org/r/20230609081518.3039120-2-qi.zheng@linux.dev
Reported-by: kernel test robot <yujie.liu@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202305230837.db2c233f-yujie.liu@intel.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yujie Liu <yujie.liu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The reconfigure / remount code takes a lot of effort to protect
filesystem's reconfiguration code from racing writes on remounting
read-only. However during remounting read-only filesystem to read-write
mode userspace writes can start immediately once we clear SB_RDONLY
flag. This is inconvenient for example for ext4 because we need to do
some writes to the filesystem (such as preparation of quota files)
before we can take userspace writes so we are clearing SB_RDONLY flag
before we are fully ready to accept userpace writes and syzbot has found
a way to exploit this [1]. Also as far as I'm reading the code
the filesystem remount code was protected from racing writes in the
legacy mount path by the mount's MNT_READONLY flag so this is relatively
new problem. It is actually fairly easy to protect remount read-write
from racing writes using sb->s_readonly_remount flag so let's just do
that instead of having to workaround these races in the filesystem code.
[1] https://lore.kernel.org/all/00000000000006a0df05f6667499@google.com/T/
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230615113848.8439-1-jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
There is no real need to store the open mode in the super_block now.
It is only used by f2fs, which can easily recalculate it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to return the open flags for blkdev_get_by* for passed in
super block flags instead of open coding the logic in many places.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder. Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.
For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new ->shutdown super operation that can be used to tell the file
system to shut down, and call it from newly created holder ops when the
block device under a file system shuts down.
This only covers the main block device for "simple" file systems using
get_tree_bdev / mount_bdev. File systems their own get_tree method
or opening additional devices will need to set up their own
blk_holder_ops.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new blk_holder_ops structure, which is passed to blkdev_get_by_* and
installed in the block_device for exclusive claims. It will be used to
allow the block layer to call back into the user of the block device for
thing like notification of a removed device or a device resize.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
wait_unfrozen waitqueue is used only in quota code to wait for
filesystem to become unfrozen. In that place we can just use
sb_start_write() - sb_end_write() pair to achieve the same. So just
remove the waitqueue.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230525141710.7595-1-jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Message-Id: <20230510221119.3508930-1-azeemshaikh38@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Now there are no readers of shrinker_rwsem, so we can simply replace it
with mutex lock.
Link: https://lkml.kernel.org/r/20230313112819.38938-9-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Merge tag 'for-6.3/dio-2023-02-16' of git://git.kernel.dk/linux
Pull legacy dio update from Jens Axboe:
"We only have a few file systems that use the old dio code, make them
select it rather than build it unconditionally"
* tag 'for-6.3/dio-2023-02-16' of git://git.kernel.dk/linux:
fs: build the legacy direct I/O code conditionally
fs: move sb_init_dio_done_wq out of direct-io.c
Simplify the implementation of the test_dummy_encryption mount option by
adding the "test dummy key" on-demand.
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Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux
Pull fscrypt updates from Eric Biggers:
"Simplify the implementation of the test_dummy_encryption mount option
by adding the 'test dummy key' on-demand"
* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux:
fscrypt: clean up fscrypt_add_test_dummy_key()
fs/super.c: stop calling fscrypt_destroy_keyring() from __put_super()
f2fs: stop calling fscrypt_add_test_dummy_key()
ext4: stop calling fscrypt_add_test_dummy_key()
fscrypt: add the test dummy encryption key on-demand
Now that the key associated with the "test_dummy_operation" mount option
is added on-demand when it's needed, rather than immediately when the
filesystem is mounted, fscrypt_destroy_keyring() no longer needs to be
called from __put_super() to avoid a memory leak on mount failure.
Remove this call, which was causing confusion because it appeared to be
a sleep-in-atomic bug (though it wasn't, for a somewhat-subtle reason).
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230208062107.199831-5-ebiggers@kernel.org
Currently, filp_close() and generic_shutdown_super() use printk() to log
messages when bugs are detected. This is problematic because infrastructure
like syzkaller has no idea that this message indicates a bug.
In addition, some people explicitly want their kernels to BUG() when kernel
data corruption has been detected (CONFIG_BUG_ON_DATA_CORRUPTION).
And finally, when generic_shutdown_super() detects remaining inodes on a
system without CONFIG_BUG_ON_DATA_CORRUPTION, it would be nice if later
accesses to a busy inode would at least crash somewhat cleanly rather than
walking through freed memory.
To address all three, use CHECK_DATA_CORRUPTION() when kernel bugs are
detected.
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
sb_init_dio_done_wq is also used by the iomap code, so move it to
super.c in preparation for building direct-io.c conditionally.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230125065839.191256-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Qi Zheng