* Realtime device subsystem
- Cleanup usage of xfs_rtblock_t and xfs_fsblock_t data types.
- Replace open coded conversions between rt blocks and rt extents with
calls to static inline helpers.
- Replace open coded realtime geometry compuation and macros with helper
functions.
- CPU usage optimizations for realtime allocator.
- Misc. Bug fixes associated with Realtime device.
* Allow read operations to execute while an FICLONE ioctl is being serviced.
* Misc. bug fixes
- Alert user when xfs_droplink() encounters an inode with a link count of zero.
- Handle the case where the allocator could return zero extents when
servicing an fallocate request.
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
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Merge tag 'xfs-6.7-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull xfs updates from Chandan Babu:
- Realtime device subsystem:
- Cleanup usage of xfs_rtblock_t and xfs_fsblock_t data types
- Replace open coded conversions between rt blocks and rt extents
with calls to static inline helpers
- Replace open coded realtime geometry compuation and macros with
helper functions
- CPU usage optimizations for realtime allocator
- Misc bug fixes associated with Realtime device
- Allow read operations to execute while an FICLONE ioctl is being
serviced
- Misc bug fixes:
- Alert user when xfs_droplink() encounters an inode with a link
count of zero
- Handle the case where the allocator could return zero extents when
servicing an fallocate request
* tag 'xfs-6.7-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (40 commits)
xfs: allow read IO and FICLONE to run concurrently
xfs: handle nimaps=0 from xfs_bmapi_write in xfs_alloc_file_space
xfs: introduce protection for drop nlink
xfs: don't look for end of extent further than necessary in xfs_rtallocate_extent_near()
xfs: don't try redundant allocations in xfs_rtallocate_extent_near()
xfs: limit maxlen based on available space in xfs_rtallocate_extent_near()
xfs: return maximum free size from xfs_rtany_summary()
xfs: invert the realtime summary cache
xfs: simplify rt bitmap/summary block accessor functions
xfs: simplify xfs_rtbuf_get calling conventions
xfs: cache last bitmap block in realtime allocator
xfs: use accessor functions for summary info words
xfs: consolidate realtime allocation arguments
xfs: create helpers for rtsummary block/wordcount computations
xfs: use accessor functions for bitmap words
xfs: create helpers for rtbitmap block/wordcount computations
xfs: create a helper to handle logging parts of rt bitmap/summary blocks
xfs: convert rt summary macros to helpers
xfs: convert open-coded xfs_rtword_t pointer accesses to helper
xfs: remove XFS_BLOCKWSIZE and XFS_BLOCKWMASK macros
...
One of our VM cluster management products needs to snapshot KVM image
files so that they can be restored in case of failure. Snapshotting is
done by redirecting VM disk writes to a sidecar file and using reflink
on the disk image, specifically the FICLONE ioctl as used by
"cp --reflink". Reflink locks the source and destination files while it
operates, which means that reads from the main vm disk image are blocked,
causing the vm to stall. When an image file is heavily fragmented, the
copy process could take several minutes. Some of the vm image files have
50-100 million extent records, and duplicating that much metadata locks
the file for 30 minutes or more. Having activities suspended for such
a long time in a cluster node could result in node eviction.
Clone operations and read IO do not change any data in the source file,
so they should be able to run concurrently. Demote the exclusive locks
taken by FICLONE to shared locks to allow reads while cloning. While a
clone is in progress, writes will take the IOLOCK_EXCL, so they block
until the clone completes.
Link: https://lore.kernel.org/linux-xfs/8911B94D-DD29-4D6E-B5BC-32EAF1866245@oracle.com/
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
When abnormal drop_nlink are detected on the inode,
return error, to avoid corruption propagation.
Signed-off-by: Cheng Lin <cheng.lin130@zte.com.cn>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
During review of the patcheset that provided reloading of the incore
iunlink list, Dave made a few suggestions, and I updated the copy in my
dev tree. Unfortunately, I then got distracted by ... who even knows
what ... and forgot to backport those changes from my dev tree to my
release candidate branch. I then sent multiple pull requests with stale
patches, and that's what was merged into -rc3.
So.
This patch re-adds the use of an unlocked iunlink list check to
determine if we want to allocate the resources to recreate the incore
list. Since lost iunlinked inodes are supposed to be rare, this change
helps us avoid paying the transaction and AGF locking costs every time
we open any inode.
This also re-adds the shutdowns on failure, and re-applies the
restructuring of the inner loop in xfs_inode_reload_unlinked_bucket, and
re-adds a requested comment about the quotachecking code.
Retain the original RVB tag from Dave since there's no code change from
the last submission.
Fixes: 68b957f64f ("xfs: load uncached unlinked inodes into memory on demand")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Teach quotacheck to reload the unlinked inode lists when walking the
inode table. This requires extra state handling, since it's possible
that a reloaded inode will get inactivated before quotacheck tries to
scan it; in this case, we need to ensure that the reloaded inode does
not have dquots attached when it is freed.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
The previous patch to reload unrecovered unlinked inodes when adding a
newly created inode to the unlinked list is missing a key piece of
functionality. It doesn't handle the case that someone calls xfs_iget
on an inode that is not the last item in the incore list. For example,
if at mount time the ondisk iunlink bucket looks like this:
AGI -> 7 -> 22 -> 3 -> NULL
None of these three inodes are cached in memory. Now let's say that
someone tries to open inode 3 by handle. We need to walk the list to
make sure that inodes 7 and 22 get loaded cold, and that the
i_prev_unlinked of inode 3 gets set to 22.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Alter the definition of i_prev_unlinked slightly to make it more obvious
when an inode with 0 link count is not part of the iunlink bucket lists
rooted in the AGI. This distinction is necessary because it is not
sufficient to check inode.i_nlink to decide if an inode is on the
unlinked list. Updates to i_nlink can happen while holding only
ILOCK_EXCL, but updates to an inode's position in the AGI unlinked list
(which happen after the nlink update) requires both ILOCK_EXCL and the
AGI buffer lock.
The next few patches will make it possible to reload an entire unlinked
bucket list when we're walking the inode table or performing handle
operations and need more than the ability to iget the last inode in the
chain.
The upcoming directory repair code also needs to be able to make this
distinction to decide if a zero link count directory should be moved to
the orphanage or allowed to inactivate. An upcoming enhancement to the
online AGI fsck code will need this distinction to check and rebuild the
AGI unlinked buckets.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
shrikanth hegde reports that filesystems fail shortly after mount with
the following failure:
WARNING: CPU: 56 PID: 12450 at fs/xfs/xfs_inode.c:1839 xfs_iunlink_lookup+0x58/0x80 [xfs]
This of course is the WARN_ON_ONCE in xfs_iunlink_lookup:
ip = radix_tree_lookup(&pag->pag_ici_root, agino);
if (WARN_ON_ONCE(!ip || !ip->i_ino)) { ... }
From diagnostic data collected by the bug reporters, it would appear
that we cleanly mounted a filesystem that contained unlinked inodes.
Unlinked inodes are only processed as a final step of log recovery,
which means that clean mounts do not process the unlinked list at all.
Prior to the introduction of the incore unlinked lists, this wasn't a
problem because the unlink code would (very expensively) traverse the
entire ondisk metadata iunlink chain to keep things up to date.
However, the incore unlinked list code complains when it realizes that
it is out of sync with the ondisk metadata and shuts down the fs, which
is bad.
Ritesh proposed to solve this problem by unconditionally parsing the
unlinked lists at mount time, but this imposes a mount time cost for
every filesystem to catch something that should be very infrequent.
Instead, let's target the places where we can encounter a next_unlinked
pointer that refers to an inode that is not in cache, and load it into
cache.
Note: This patch does not address the problem of iget loading an inode
from the middle of the iunlink list and needing to set i_prev_unlinked
correctly.
Reported-by: shrikanth hegde <sshegde@linux.vnet.ibm.com>
Triaged-by: Ritesh Harjani <ritesh.list@gmail.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
In the next patch, we're going to prohibit log recovery if the primary
superblock contains an unrecognized rocompat feature bit even on
readonly mounts. This requires removing all the code in the log
mounting process that temporarily disables the readonly state.
Unfortunately, inode inactivation disables itself on readonly mounts.
Clearing the iunlinked lists after log recovery needs inactivation to
run to free the unreferenced inodes, which (AFAICT) is the only reason
why log mounting plays games with the readonly state in the first place.
Therefore, change the inactivation predicates to allow inactivation
during log recovery of a readonly mount.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705190309.579783-80-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Unlinked list recovery requires errors removing the inode the from
the unlinked list get fed back to the main recovery loop. Now that
we offload the unlinking to the inodegc work, we don't get errors
being fed back when we trip over a corruption that prevents the
inode from being removed from the unlinked list.
This means we never clear the corrupt unlinked list bucket,
resulting in runtime operations eventually tripping over it and
shutting down.
Fix this by collecting inodegc worker errors and feed them
back to the flush caller. This is largely best effort - the only
context that really cares is log recovery, and it only flushes a
single inode at a time so we don't need complex synchronised
handling. Essentially the inodegc workers will capture the first
error that occurs and the next flush will gather them and clear
them. The flush itself will only report the first gathered error.
In the cases where callers can return errors, propagate the
collected inodegc flush error up the error handling chain.
In the case of inode unlinked list recovery, there are several
superfluous calls to flush queued unlinked inodes -
xlog_recover_iunlink_bucket() guarantees that it has flushed the
inodegc and collected errors before it returns. Hence nothing in the
calling path needs to run a flush, even when an error is returned.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
* Fix a deadlock in the free space allocator due to the AG-walking
algorithm forgetting to follow AG-order locking rules.
* Make the inode allocator prefer existing free inodes instead of
failing to allocate new inode chunks when free space is low.
* Set minleft correctly when setting allocator parameters for bmap
changes.
* Fix uninitialized variable access in the getfsmap code.
* Make a distinction between active and passive per-AG structure
references. For now, active references are taken to perform some
work in an AG on behalf of a high level operation; passive references
are used by lower level code to finish operations started by other
threads. Eventually this will become part of online shrink.
* Split out all the different allocator strategies into separate
functions to move us away from design antipattern of filling out a
huge structure for various differentish things and issuing a single
function multiplexing call.
* Various cleanups in the filestreams allocator code, which we might
very well want to deprecate instead of continuing.
* Fix a bug with the agi rotor code that was introduced earlier in this
series.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'xfs-6.3-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull moar xfs updates from Darrick Wong:
"This contains a fix for a deadlock in the allocator. It continues the
slow march towards being able to offline AGs, and it refactors the
interface to the xfs allocator to be less indirection happy.
Summary:
- Fix a deadlock in the free space allocator due to the AG-walking
algorithm forgetting to follow AG-order locking rules
- Make the inode allocator prefer existing free inodes instead of
failing to allocate new inode chunks when free space is low
- Set minleft correctly when setting allocator parameters for bmap
changes
- Fix uninitialized variable access in the getfsmap code
- Make a distinction between active and passive per-AG structure
references. For now, active references are taken to perform some
work in an AG on behalf of a high level operation; passive
references are used by lower level code to finish operations
started by other threads. Eventually this will become part of
online shrink
- Split out all the different allocator strategies into separate
functions to move us away from design antipattern of filling out a
huge structure for various differentish things and issuing a single
function multiplexing call
- Various cleanups in the filestreams allocator code, which we might
very well want to deprecate instead of continuing
- Fix a bug with the agi rotor code that was introduced earlier in
this series"
* tag 'xfs-6.3-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (44 commits)
xfs: restore old agirotor behavior
xfs: fix uninitialized variable access
xfs: refactor the filestreams allocator pick functions
xfs: return a referenced perag from filestreams allocator
xfs: pass perag to filestreams tracing
xfs: use for_each_perag_wrap in xfs_filestream_pick_ag
xfs: track an active perag reference in filestreams
xfs: factor out MRU hit case in xfs_filestream_select_ag
xfs: remove xfs_filestream_select_ag() longest extent check
xfs: merge new filestream AG selection into xfs_filestream_select_ag()
xfs: merge filestream AG lookup into xfs_filestream_select_ag()
xfs: move xfs_bmap_btalloc_filestreams() to xfs_filestreams.c
xfs: use xfs_bmap_longest_free_extent() in filestreams
xfs: get rid of notinit from xfs_bmap_longest_free_extent
xfs: factor out filestreams from xfs_bmap_btalloc_nullfb
xfs: convert trim to use for_each_perag_range
xfs: convert xfs_alloc_vextent_iterate_ags() to use perag walker
xfs: move the minimum agno checks into xfs_alloc_vextent_check_args
xfs: fold xfs_alloc_ag_vextent() into callers
xfs: move allocation accounting to xfs_alloc_vextent_set_fsbno()
...
The tp->t_firstblock field is now raelly tracking the highest AG we
have locked, not the block number of the highest allocation we've
made. It's purpose is to prevent AGF locking deadlocks, so rename it
to "highest AG" and simplify the implementation to just track the
agno rather than a fsbno.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Clean up resources if resetting the dotdot entry doesn't succeed.
Observed through code inspection.
Fixes: 5838d0356b ("xfs: reset child dir '..' entry when unlinking child")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
xfs_rename can update up to 5 inodes: src_dp, target_dp, src_ip, target_ip
and wip. So we need to increase the inode reservation to match.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
A while ago we introduced a dedicated vfs{g,u}id_t type in commit
1e5267cd08 ("mnt_idmapping: add vfs{g,u}id_t"). We already switched
over a good part of the VFS. Ultimately we will remove all legacy
idmapped mount helpers that operate only on k{g,u}id_t in favor of the
new type safe helpers that operate on vfs{g,u}id_t.
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The "%Ld" specifier, which represents long long unsigned,
doesn't meet C language standard, and even more,
it makes people easily mistake with "%ld", which represent
long unsigned. So replace "%Ld" with "lld".
Do the same with "%Lu".
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve latency
and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place
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Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
Introduce xfs_mmaplock_two_inodes_and_break_dax_layout() for dax files who
are going to be deduped. After that, call compare range function only
when files are both DAX or not.
Link: https://lkml.kernel.org/r/20220603053738.1218681-15-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.wiliams@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This series fixes a use-after-free bug that syzbot uncovered. The UAF
itself is a result of a race condition between getxattr and removexattr
because callers to getxattr do not necessarily take any sort of locks
before calling into the filesystem.
Although the race condition itself can be fixed through clever use of a
memory barrier, further consideration of the use cases of extended
attributes shows that most files always have at least one attribute, so
we might as well make them permanent.
v2: Minor tweaks suggested by Dave, and convert some more macros to
helper functions.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'make-attr-fork-permanent-5.20_2022-07-14' of git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-5.20-mergeB
xfs: make attr forks permanent
This series fixes a use-after-free bug that syzbot uncovered. The UAF
itself is a result of a race condition between getxattr and removexattr
because callers to getxattr do not necessarily take any sort of locks
before calling into the filesystem.
Although the race condition itself can be fixed through clever use of a
memory barrier, further consideration of the use cases of extended
attributes shows that most files always have at least one attribute, so
we might as well make them permanent.
v2: Minor tweaks suggested by Dave, and convert some more macros to
helper functions.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
* tag 'make-attr-fork-permanent-5.20_2022-07-14' of git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
xfs: replace inode fork size macros with functions
xfs: replace XFS_IFORK_Q with a proper predicate function
xfs: use XFS_IFORK_Q to determine the presence of an xattr fork
xfs: make inode attribute forks a permanent part of struct xfs_inode
xfs: convert XFS_IFORK_PTR to a static inline helper
To facilitate future improvements in inode logging and improving
inode cluster buffer locking order consistency, we need a new
mechanism for defering inode cluster buffer modifications during
unlinked list modifications.
The unlinked inode list buffer locking is complex. The unlinked
list is unordered - we add to the tail, remove from where-ever the
inode is in the list. Hence we might need to lock two inode buffers
here (previous inode in list and the one being removed). While we
can order the locking of these buffers correctly within the confines
of the unlinked list, there may be other inodes that need buffer
locking in the same transaction. e.g. O_TMPFILE being linked into a
directory also modifies the directory inode.
Hence we need a mechanism for defering unlinked inode list updates
until a point where we know that all modifications have been made
and all that remains is to lock and modify the cluster buffers.
We can do this by first observing that we serialise unlinked list
modifications by holding the AGI buffer lock. IOWs, the AGI is going
to be locked until the transaction commits any time we modify the
unlinked list. Hence it doesn't matter when in the unlink
transactions that we actually load, lock and modify the inode
cluster buffer.
We add an in-memory unlinked inode log item to defer the inode
cluster buffer update to transaction commit time where it can be
ordered with all the other inode cluster operations that need to be
done. Essentially all we need to do is record the inodes that need
to have their unlinked list pointer updated in a new log item that
we attached to the transaction.
This log item exists purely for the purpose of delaying the update
of the unlinked list pointer until the inode cluster buffer can be
locked in the correct order around the other inode cluster buffers.
It plays no part in the actual commit, and there's no change to
anything that is written to the log. i.e. the inode cluster buffers
still have to be fully logged here (not just ordered) as log
recovery depedends on this to replay mods to the unlinked inode
list.
Hence if we add a "precommit" hook into xfs_trans_commit()
to run a "precommit" operation on these iunlink log items, we can
delay the locking, modification and logging of the inode cluster
buffer until after all other modifications have been made. The
precommit hook reuires us to sort the items that are going to be run
so that we can lock precommit items in the correct order as we
perform the modifications they describe.
To make this unlinked inode list processing simpler and easier to
implement as a log item, we need to change the way we track the
unlinked list in memory. Starting from the observation that an inode
on the unlinked list is pinned in memory by the VFS, we can use the
xfs_inode itself to track the unlinked list. To do this efficiently,
we want the unlinked list to be a double linked list. The problem
here is that we need a list per AGI unlinked list, and there are 64
of these per AGI. The approach taken in this patchset is to shadow
the AGI unlinked list heads in the perag, and link inodes by agino,
hence requiring only 8 extra bytes per inode to track this state.
We can then use the agino pointers for lockless inode cache lookups
to retreive the inode. The aginos in the inode are modified only
under the AGI lock, just like the cluster buffer pointers, so we
don't need any extra locking here. The i_next_unlinked field tracks
the on-disk value of the unlinked list, and the i_prev_unlinked is a
purely in-memory pointer that enables us to efficiently remove
inodes from the middle of the list.
This results in moving a lot of the unlink modification work into
the precommit operations on the unlink log item. Tracking all the
unlinked inodes in the inodes themselves also gets rid of the
unlinked list reference hash table that is used to track this back
pointer relationship. This greatly simplifies the the unlinked list
modification code, and removes memory allocations in this hot path
to track back pointers. This, overall, slightly reduces the CPU
overhead of the unlink path.
The result of this log item means that we move all the actual
manipulation of objects to be logged out of the iunlink path and
into the iunlink item. This allows for future optimisation of this
mechanism without needing changes to high level unlink path, as
well as making the unlink lock ordering predictable and synchronised
with other operations that may require inode cluster locking.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
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Merge tag 'xfs-iunlink-item-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs into xfs-5.20-mergeB
xfs: introduce in-memory inode unlink log items
To facilitate future improvements in inode logging and improving
inode cluster buffer locking order consistency, we need a new
mechanism for defering inode cluster buffer modifications during
unlinked list modifications.
The unlinked inode list buffer locking is complex. The unlinked
list is unordered - we add to the tail, remove from where-ever the
inode is in the list. Hence we might need to lock two inode buffers
here (previous inode in list and the one being removed). While we
can order the locking of these buffers correctly within the confines
of the unlinked list, there may be other inodes that need buffer
locking in the same transaction. e.g. O_TMPFILE being linked into a
directory also modifies the directory inode.
Hence we need a mechanism for defering unlinked inode list updates
until a point where we know that all modifications have been made
and all that remains is to lock and modify the cluster buffers.
We can do this by first observing that we serialise unlinked list
modifications by holding the AGI buffer lock. IOWs, the AGI is going
to be locked until the transaction commits any time we modify the
unlinked list. Hence it doesn't matter when in the unlink
transactions that we actually load, lock and modify the inode
cluster buffer.
We add an in-memory unlinked inode log item to defer the inode
cluster buffer update to transaction commit time where it can be
ordered with all the other inode cluster operations that need to be
done. Essentially all we need to do is record the inodes that need
to have their unlinked list pointer updated in a new log item that
we attached to the transaction.
This log item exists purely for the purpose of delaying the update
of the unlinked list pointer until the inode cluster buffer can be
locked in the correct order around the other inode cluster buffers.
It plays no part in the actual commit, and there's no change to
anything that is written to the log. i.e. the inode cluster buffers
still have to be fully logged here (not just ordered) as log
recovery depedends on this to replay mods to the unlinked inode
list.
Hence if we add a "precommit" hook into xfs_trans_commit()
to run a "precommit" operation on these iunlink log items, we can
delay the locking, modification and logging of the inode cluster
buffer until after all other modifications have been made. The
precommit hook reuires us to sort the items that are going to be run
so that we can lock precommit items in the correct order as we
perform the modifications they describe.
To make this unlinked inode list processing simpler and easier to
implement as a log item, we need to change the way we track the
unlinked list in memory. Starting from the observation that an inode
on the unlinked list is pinned in memory by the VFS, we can use the
xfs_inode itself to track the unlinked list. To do this efficiently,
we want the unlinked list to be a double linked list. The problem
here is that we need a list per AGI unlinked list, and there are 64
of these per AGI. The approach taken in this patchset is to shadow
the AGI unlinked list heads in the perag, and link inodes by agino,
hence requiring only 8 extra bytes per inode to track this state.
We can then use the agino pointers for lockless inode cache lookups
to retreive the inode. The aginos in the inode are modified only
under the AGI lock, just like the cluster buffer pointers, so we
don't need any extra locking here. The i_next_unlinked field tracks
the on-disk value of the unlinked list, and the i_prev_unlinked is a
purely in-memory pointer that enables us to efficiently remove
inodes from the middle of the list.
This results in moving a lot of the unlink modification work into
the precommit operations on the unlink log item. Tracking all the
unlinked inodes in the inodes themselves also gets rid of the
unlinked list reference hash table that is used to track this back
pointer relationship. This greatly simplifies the the unlinked list
modification code, and removes memory allocations in this hot path
to track back pointers. This, overall, slightly reduces the CPU
overhead of the unlink path.
The result of this log item means that we move all the actual
manipulation of objects to be logged out of the iunlink path and
into the iunlink item. This allows for future optimisation of this
mechanism without needing changes to high level unlink path, as
well as making the unlink lock ordering predictable and synchronised
with other operations that may require inode cluster locking.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
* tag 'xfs-iunlink-item-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
xfs: add in-memory iunlink log item
xfs: add log item precommit operation
xfs: combine iunlink inode update functions
xfs: clean up xfs_iunlink_update_inode()
xfs: double link the unlinked inode list
xfs: introduce xfs_iunlink_lookup
xfs: refactor xlog_recover_process_iunlinks()
xfs: track the iunlink list pointer in the xfs_inode
xfs: factor the xfs_iunlink functions
xfs: flush inode gc workqueue before clearing agi bucket
Now that we have a clean operation to update the di_next_unlinked
field of inode cluster buffers, we can easily defer this operation
to transaction commit time so we can order the inode cluster buffer
locking consistently.
To do this, we introduce a new in-memory log item to track the
unlinked list item modification that we are going to make. This
follows the same observations as the in-memory double linked list
used to track unlinked inodes in that the inodes on the list are
pinned in memory and cannot go away, and hence we can simply
reference them for the duration of the transaction without needing
to take active references or pin them or look them up.
This allows us to pass the xfs_inode to the transaction commit code
along with the modification to be made, and then order the logged
modifications via the ->iop_sort and ->iop_precommit operations
for the new log item type. As this is an in-memory log item, it
doesn't have formatting, CIL or AIL operational hooks - it exists
purely to run the inode unlink modifications and is then removed
from the transaction item list and freed once the precommit
operation has run.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Combine the logging of the inode unlink list update into the
calling function that looks up the buffer we end up logging. These
do not need to be separate functions as they are both short, simple
operations and there's only a single call path through them. This
new function will end up being the core of the iunlink log item
processing...
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
We no longer need to have this function return the previous next
agino value from the on-disk inode as we have it in the in-core
inode now.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Now we have forwards traversal via the incore inode in place, we now
need to add back pointers to the incore inode to entirely replace
the back reference cache. We use the same lookup semantics and
constraints as for the forwards pointer lookups during unlinks, and
so we can look up any inode in the unlinked list directly and update
the list pointers, forwards or backwards, at any time.
The only wrinkle in converting the unlinked list manipulations to
use in-core previous pointers is that log recovery doesn't have the
incore inode state built up so it can't just read in an inode and
release it to finish off the unlink. Hence we need to modify the
traversal in recovery to read one inode ahead before we
release the inode at the head of the list. This populates the
next->prev relationship sufficient to be able to replay the unlinked
list and hence greatly simplify the runtime code.
This recovery algorithm also requires that we actually remove inodes
from the unlinked list one at a time as background inode
inactivation will result in unlinked list removal racing with the
building of the in-memory unlinked list state. We could serialise
this by holding the AGI buffer lock when constructing the in memory
state, but all that does is lockstep background processing with list
building. It is much simpler to flush the inodegc immediately after
releasing the inode so that it is unlinked immediately and there is
no races present at all.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
When an inode is on an unlinked list during normal operation, it is
guaranteed to be pinned in memory as it is either referenced by the
current unlink operation or it has a open file descriptor that
references it and has it pinned in memory. Hence to look up an inode
on the unlinked list, we can do a direct inode cache lookup and
always expect the lookup to succeed.
Add a function to do this lookup based on the agino that we use to
link the chain of unlinked inodes together so we can begin the
conversion the unlinked list manipulations to use in-memory inodes
rather than inode cluster buffers and remove the backref cache.
Use this lookup function to replace the on-disk inode buffer walk
when removing inodes from the unlinked list with an in-core inode
unlinked list walk.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Having direct access to the i_next_unlinked pointer in unlinked
inodes greatly simplifies the processing of inodes on the unlinked
list. We no longer need to look up the inode buffer just to find
next inode in the list if the xfs_inode is in memory. These
improvements will be realised over upcoming patches as other
dependencies on the inode buffer for unlinked list processing are
removed.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Prep work that separates the locking that protects the unlinked list
from the actual operations being performed. This also helps document
the fact they are performing list insert and remove operations. No
functional code change.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Replace this shouty macro with a real C function that has a more
descriptive name.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Modify xfs_ifork_ptr to return a NULL pointer if the caller asks for the
attribute fork but i_forkoff is zero. This eliminates the ambiguity
between i_forkoff and i_af.if_present, which should make it easier to
understand the lifetime of attr forks.
While we're at it, remove the if_present checks around calls to
xfs_idestroy_fork and xfs_ifork_zap_attr since they can both handle attr
forks that have already been torn down.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Syzkaller reported a UAF bug a while back:
==================================================================
BUG: KASAN: use-after-free in xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127
Read of size 4 at addr ffff88802cec919c by task syz-executor262/2958
CPU: 2 PID: 2958 Comm: syz-executor262 Not tainted
5.15.0-0.30.3-20220406_1406 #3
Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29
04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x82/0xa9 lib/dump_stack.c:106
print_address_description.constprop.9+0x21/0x2d5 mm/kasan/report.c:256
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold.14+0x7f/0x11b mm/kasan/report.c:459
xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127
xfs_attr_get+0x378/0x4c2 fs/xfs/libxfs/xfs_attr.c:159
xfs_xattr_get+0xe3/0x150 fs/xfs/xfs_xattr.c:36
__vfs_getxattr+0xdf/0x13d fs/xattr.c:399
cap_inode_need_killpriv+0x41/0x5d security/commoncap.c:300
security_inode_need_killpriv+0x4c/0x97 security/security.c:1408
dentry_needs_remove_privs.part.28+0x21/0x63 fs/inode.c:1912
dentry_needs_remove_privs+0x80/0x9e fs/inode.c:1908
do_truncate+0xc3/0x1e0 fs/open.c:56
handle_truncate fs/namei.c:3084 [inline]
do_open fs/namei.c:3432 [inline]
path_openat+0x30ab/0x396d fs/namei.c:3561
do_filp_open+0x1c4/0x290 fs/namei.c:3588
do_sys_openat2+0x60d/0x98c fs/open.c:1212
do_sys_open+0xcf/0x13c fs/open.c:1228
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0x0
RIP: 0033:0x7f7ef4bb753d
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48
89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73
01 c3 48 8b 0d 1b 79 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007f7ef52c2ed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 0000000000404148 RCX: 00007f7ef4bb753d
RDX: 00007f7ef4bb753d RSI: 0000000000000000 RDI: 0000000020004fc0
RBP: 0000000000404140 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 00007ffd794db37f R14: 00007ffd794db470 R15: 00007f7ef52c2fc0
</TASK>
Allocated by task 2953:
kasan_save_stack+0x19/0x38 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x68/0x7c mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc_node mm/slub.c:3213 [inline]
slab_alloc mm/slub.c:3221 [inline]
kmem_cache_alloc+0x11b/0x3eb mm/slub.c:3226
kmem_cache_zalloc include/linux/slab.h:711 [inline]
xfs_ifork_alloc+0x25/0xa2 fs/xfs/libxfs/xfs_inode_fork.c:287
xfs_bmap_add_attrfork+0x3f2/0x9b1 fs/xfs/libxfs/xfs_bmap.c:1098
xfs_attr_set+0xe38/0x12a7 fs/xfs/libxfs/xfs_attr.c:746
xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59
__vfs_setxattr+0x11b/0x177 fs/xattr.c:180
__vfs_setxattr_noperm+0x128/0x5e0 fs/xattr.c:214
__vfs_setxattr_locked+0x1d4/0x258 fs/xattr.c:275
vfs_setxattr+0x154/0x33d fs/xattr.c:301
setxattr+0x216/0x29f fs/xattr.c:575
__do_sys_fsetxattr fs/xattr.c:632 [inline]
__se_sys_fsetxattr fs/xattr.c:621 [inline]
__x64_sys_fsetxattr+0x243/0x2fe fs/xattr.c:621
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0x0
Freed by task 2949:
kasan_save_stack+0x19/0x38 mm/kasan/common.c:38
kasan_set_track+0x1c/0x21 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free mm/kasan/common.c:328 [inline]
__kasan_slab_free+0xe2/0x10e mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1700 [inline]
slab_free_freelist_hook mm/slub.c:1726 [inline]
slab_free mm/slub.c:3492 [inline]
kmem_cache_free+0xdc/0x3ce mm/slub.c:3508
xfs_attr_fork_remove+0x8d/0x132 fs/xfs/libxfs/xfs_attr_leaf.c:773
xfs_attr_sf_removename+0x5dd/0x6cb fs/xfs/libxfs/xfs_attr_leaf.c:822
xfs_attr_remove_iter+0x68c/0x805 fs/xfs/libxfs/xfs_attr.c:1413
xfs_attr_remove_args+0xb1/0x10d fs/xfs/libxfs/xfs_attr.c:684
xfs_attr_set+0xf1e/0x12a7 fs/xfs/libxfs/xfs_attr.c:802
xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59
__vfs_removexattr+0x106/0x16a fs/xattr.c:468
cap_inode_killpriv+0x24/0x47 security/commoncap.c:324
security_inode_killpriv+0x54/0xa1 security/security.c:1414
setattr_prepare+0x1a6/0x897 fs/attr.c:146
xfs_vn_change_ok+0x111/0x15e fs/xfs/xfs_iops.c:682
xfs_vn_setattr_size+0x5f/0x15a fs/xfs/xfs_iops.c:1065
xfs_vn_setattr+0x125/0x2ad fs/xfs/xfs_iops.c:1093
notify_change+0xae5/0x10a1 fs/attr.c:410
do_truncate+0x134/0x1e0 fs/open.c:64
handle_truncate fs/namei.c:3084 [inline]
do_open fs/namei.c:3432 [inline]
path_openat+0x30ab/0x396d fs/namei.c:3561
do_filp_open+0x1c4/0x290 fs/namei.c:3588
do_sys_openat2+0x60d/0x98c fs/open.c:1212
do_sys_open+0xcf/0x13c fs/open.c:1228
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0x0
The buggy address belongs to the object at ffff88802cec9188
which belongs to the cache xfs_ifork of size 40
The buggy address is located 20 bytes inside of
40-byte region [ffff88802cec9188, ffff88802cec91b0)
The buggy address belongs to the page:
page:00000000c3af36a1 refcount:1 mapcount:0 mapping:0000000000000000
index:0x0 pfn:0x2cec9
flags: 0xfffffc0000200(slab|node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc0000200 ffffea00009d2580 0000000600000006 ffff88801a9ffc80
raw: 0000000000000000 0000000080490049 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88802cec9080: fb fb fb fc fc fa fb fb fb fb fc fc fb fb fb fb
ffff88802cec9100: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc
>ffff88802cec9180: fc fa fb fb fb fb fc fc fa fb fb fb fb fc fc fb
^
ffff88802cec9200: fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb
ffff88802cec9280: fb fb fc fc fa fb fb fb fb fc fc fa fb fb fb fb
==================================================================
The root cause of this bug is the unlocked access to xfs_inode.i_afp
from the getxattr code paths while trying to determine which ILOCK mode
to use to stabilize the xattr data. Unfortunately, the VFS does not
acquire i_rwsem when vfs_getxattr (or listxattr) call into the
filesystem, which means that getxattr can race with a removexattr that's
tearing down the attr fork and crash:
xfs_attr_set: xfs_attr_get:
xfs_attr_fork_remove: xfs_ilock_attr_map_shared:
xfs_idestroy_fork(ip->i_afp);
kmem_cache_free(xfs_ifork_cache, ip->i_afp);
if (ip->i_afp &&
ip->i_afp = NULL;
xfs_need_iread_extents(ip->i_afp))
<KABOOM>
ip->i_forkoff = 0;
Regrettably, the VFS is much more lax about i_rwsem and getxattr than
is immediately obvious -- not only does it not guarantee that we hold
i_rwsem, it actually doesn't guarantee that we *don't* hold it either.
The getxattr system call won't acquire the lock before calling XFS, but
the file capabilities code calls getxattr with and without i_rwsem held
to determine if the "security.capabilities" xattr is set on the file.
Fixing the VFS locking requires a treewide investigation into every code
path that could touch an xattr and what i_rwsem state it expects or sets
up. That could take years or even prove impossible; fortunately, we
can fix this UAF problem inside XFS.
An earlier version of this patch used smp_wmb in xfs_attr_fork_remove to
ensure that i_forkoff is always zeroed before i_afp is set to null and
changed the read paths to use smp_rmb before accessing i_forkoff and
i_afp, which avoided these UAF problems. However, the patch author was
too busy dealing with other problems in the meantime, and by the time he
came back to this issue, the situation had changed a bit.
On a modern system with selinux, each inode will always have at least
one xattr for the selinux label, so it doesn't make much sense to keep
incurring the extra pointer dereference. Furthermore, Allison's
upcoming parent pointer patchset will also cause nearly every inode in
the filesystem to have extended attributes. Therefore, make the inode
attribute fork structure part of struct xfs_inode, at a cost of 40 more
bytes.
This patch adds a clunky if_present field where necessary to maintain
the existing logic of xattr fork null pointer testing in the existing
codebase. The next patch switches the logic over to XFS_IFORK_Q and it
all goes away.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
We're about to make this logic do a bit more, so convert the macro to a
static inline function for better typechecking and fewer shouty macros.
No functional changes here.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
We got a report that "renameat2() with flags=RENAME_WHITEOUT doesn't
apply an SELinux label on xfs" as it does on other filesystems
(for example, ext4 and tmpfs.) While I'm not quite sure how labels
may interact w/ whiteout files, leaving them as unlabeled seems
inconsistent at best. Now that xfs_init_security is not static,
rename it to xfs_inode_init_security per dchinner's suggestion.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
There is a lot of overhead in functions like xfs_verify_agino() that
repeatedly calculate the geometry limits of an AG. These can be
pre-calculated as they are static and the verification context has
a per-ag context it can quickly reference.
In the case of xfs_verify_agino(), we now always have a perag
context handy, so we can store the minimum and maximum agino values
in the AG in the perag. This means we don't have to calculate
it on every call and it can be inlined in callers if we move it
to xfs_ag.h.
xfs_verify_agino_or_null() gets the same perag treatment.
xfs_agino_range() is moved to xfs_ag.c as it's not really a type
function, and it's use is largely restricted as the first and last
aginos can be grabbed straight from the perag in most cases.
Note that we leave the original xfs_verify_agino in place in
xfs_types.c as a static function as other callers in that file do
not have per-ag contexts so still need to go the long way. It's been
renamed to xfs_verify_agno_agino() to indicate it takes both an agno
and an agino to differentiate it from new function.
$ size --totals fs/xfs/built-in.a
text data bss dec hex filename
before 1482185 329588 572 1812345 1ba779 (TOTALS)
after 1481937 329588 572 1812097 1ba681 (TOTALS)
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
We have the perag in most palces we call xfs_read_agi, so pass the
perag instead of a mount/agno pair.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
We should use invalidate_lock and XFS_MMAPLOCK_SHARED to check the state
of mmap_lock rw_semaphore in xfs_isilocked(), rather than i_rwsem and
XFS_IOLOCK_SHARED.
Fixes: 2433480a7e ("xfs: Convert to use invalidate_lock")
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
There are similar lock flags assert in xfs_ilock(), xfs_ilock_nowait(),
xfs_iunlock(), thus we can factor it out into a helper that is clear.
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
For some reason commit 9a5280b312 ("xfs: reorder iunlink remove
operation in xfs_ifree") replaced a jump to the exit path in the
event of an xfs_difree() error with a direct return, which skips
releasing the perag reference acquired at the top of the function.
Restore the original code to drop the reference on error.
Fixes: 9a5280b312 ("xfs: reorder iunlink remove operation in xfs_ifree")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs: Large extent counters
The commit xfs: fix inode fork extent count overflow
(3f8a4f1d87) mentions that 10 billion
data fork extents should be possible to create. However the
corresponding on-disk field has a signed 32-bit type. Hence this
patchset extends the per-inode data fork extent counter to 64 bits
(out of which 48 bits are used to store the extent count).
Also, XFS has an attribute fork extent counter which is 16 bits
wide. A workload that,
1. Creates 1 million 255-byte sized xattrs,
2. Deletes 50% of these xattrs in an alternating manner,
3. Tries to insert 400,000 new 255-byte sized xattrs
causes the xattr extent counter to overflow.
Dave tells me that there are instances where a single file has more
than 100 million hardlinks. With parent pointers being stored in
xattrs, we will overflow the signed 16-bits wide attribute extent
counter when large number of hardlinks are created. Hence this
patchset extends the on-disk field to 32-bits.
The following changes are made to accomplish this,
1. A 64-bit inode field is carved out of existing di_pad and
di_flushiter fields to hold the 64-bit data fork extent counter.
2. The existing 32-bit inode data fork extent counter will be used to
hold the attribute fork extent counter.
3. A new incompat superblock flag to prevent older kernels from mounting
the filesystem.
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
5.18 w/ std=gnu11 compiled with gcc-5 wants flags stored in unsigned
fields to be unsigned.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The O_TMPFILE creation implementation creates a specific order of
operations for inode allocation/freeing and unlinked list
modification. Currently both are serialised by the AGI, so the order
doesn't strictly matter as long as the are both in the same
transaction.
However, if we want to move the unlinked list insertions largely out
from under the AGI lock, then we have to be concerned about the
order in which we do unlinked list modification operations.
O_TMPFILE creation tells us this order is inode allocation/free,
then unlinked list modification.
Change xfs_ifree() to use this same ordering on unlinked list
removal. This way we always guarantee that when we enter the
iunlinked list removal code from this path, we already have the AGI
locked and we don't have to worry about lock nesting AGI reads
inside unlink list locks because it's already locked and attached to
the transaction.
We can do this safely as the inode freeing and unlinked list removal
are done in the same transaction and hence are atomic operations
with respect to log recovery.
Reported-by: Frank Hofmann <fhofmann@cloudflare.com>
Fixes: 298f7bec50 ("xfs: pin inode backing buffer to the inode log item")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The maximum file size that can be represented by the data fork extent counter
in the worst case occurs when all extents are 1 block in length and each block
is 1KB in size.
With XFS_MAX_EXTCNT_DATA_FORK_SMALL representing maximum extent count and with
1KB sized blocks, a file can reach upto,
(2^31) * 1KB = 2TB
This is much larger than the theoretical maximum size of a directory
i.e. XFS_DIR2_SPACE_SIZE * 3 = ~96GB.
Since a directory's inode can never overflow its data fork extent counter,
this commit removes all the overflow checks associated with
it. xfs_dinode_verify() now performs a rough check to verify if a diretory's
data fork is larger than 96GB.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
A future commit will introduce a 64-bit on-disk data extent counter and a
32-bit on-disk attr extent counter. This commit promotes xfs_extnum_t and
xfs_aextnum_t to 64 and 32-bits in order to correctly handle in-core versions
of these quantities.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Most buffer io list operations are run with the bp->b_lock held, but
xfs_iflush_abort() can be called without the buffer lock being held
resulting in inodes being removed from the buffer list while other
list operations are occurring. This causes problems with corrupted
bp->b_io_list inode lists during filesystem shutdown, leading to
traversals that never end, double removals from the AIL, etc.
Fix this by passing the buffer to xfs_iflush_abort() if we have
it locked. If the inode is attached to the buffer, we're going to
have to remove it from the buffer list and we'd have to get the
buffer off the inode log item to do that anyway.
If we don't have a buffer passed in (e.g. from xfs_reclaim_inode())
then we can determine if the inode has a log item and if it is
attached to a buffer before we do anything else. If it does have an
attached buffer, we can lock it safely (because the inode has a
reference to it) and then perform the inode abort.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
I've been chasing a recent resurgence in generic/388 recovery
failure and/or corruption events. The events have largely been
uninitialised inode chunks being tripped over in log recovery
such as:
XFS (pmem1): User initiated shutdown received.
pmem1: writeback error on inode 12621949, offset 1019904, sector 12968096
XFS (pmem1): Log I/O Error (0x6) detected at xfs_fs_goingdown+0xa3/0xf0 (fs/xfs/xfs_fsops.c:500). Shutting down filesystem.
XFS (pmem1): Please unmount the filesystem and rectify the problem(s)
XFS (pmem1): Unmounting Filesystem
XFS (pmem1): Mounting V5 Filesystem
XFS (pmem1): Starting recovery (logdev: internal)
XFS (pmem1): bad inode magic/vsn daddr 8723584 #0 (magic=1818)
XFS (pmem1): Metadata corruption detected at xfs_inode_buf_verify+0x180/0x190, xfs_inode block 0x851c80 xfs_inode_buf_verify
XFS (pmem1): Unmount and run xfs_repair
XFS (pmem1): First 128 bytes of corrupted metadata buffer:
00000000: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
00000010: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
00000020: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
00000030: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
00000040: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
00000050: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
00000060: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
00000070: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................
XFS (pmem1): metadata I/O error in "xlog_recover_items_pass2+0x52/0xc0" at daddr 0x851c80 len 32 error 117
XFS (pmem1): log mount/recovery failed: error -117
XFS (pmem1): log mount failed
There have been isolated random other issues, too - xfs_repair fails
because it finds some corruption in symlink blocks, rmap
inconsistencies, etc - but they are nowhere near as common as the
uninitialised inode chunk failure.
The problem has clearly happened at runtime before recovery has run;
I can see the ICREATE log item in the log shortly before the
actively recovered range of the log. This means the ICREATE was
definitely created and written to the log, but for some reason the
tail of the log has been moved past the ordered buffer log item that
tracks INODE_ALLOC buffers and, supposedly, prevents the tail of the
log moving past the ICREATE log item before the inode chunk buffer
is written to disk.
Tracing the fsstress processes that are running when the filesystem
shut down immediately pin-pointed the problem:
user shutdown marks xfs_mount as shutdown
godown-213341 [008] 6398.022871: console: [ 6397.915392] XFS (pmem1): User initiated shutdown received.
.....
aild tries to push ordered inode cluster buffer
xfsaild/pmem1-213314 [001] 6398.022974: xfs_buf_trylock: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 16 pincount 0 lock 0 flags DONE|INODES|PAGES caller xfs_inode_item_push+0x8e
xfsaild/pmem1-213314 [001] 6398.022976: xfs_ilock_nowait: dev 259:1 ino 0x851c80 flags ILOCK_SHARED caller xfs_iflush_cluster+0xae
xfs_iflush_cluster() checks xfs_is_shutdown(), returns true,
calls xfs_iflush_abort() to kill writeback of the inode.
Inode is removed from AIL, drops cluster buffer reference.
xfsaild/pmem1-213314 [001] 6398.022977: xfs_ail_delete: dev 259:1 lip 0xffff88880247ed80 old lsn 7/20344 new lsn 7/21000 type XFS_LI_INODE flags IN_AIL
xfsaild/pmem1-213314 [001] 6398.022978: xfs_buf_rele: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 17 pincount 0 lock 0 flags DONE|INODES|PAGES caller xfs_iflush_abort+0xd7
.....
All inodes on cluster buffer are aborted, then the cluster buffer
itself is aborted and removed from the AIL *without writeback*:
xfsaild/pmem1-213314 [001] 6398.023011: xfs_buf_error_relse: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 2 pincount 0 lock 0 flags ASYNC|DONE|STALE|INODES|PAGES caller xfs_buf_ioend_fail+0x33
xfsaild/pmem1-213314 [001] 6398.023012: xfs_ail_delete: dev 259:1 lip 0xffff8888053efde8 old lsn 7/20344 new lsn 7/20344 type XFS_LI_BUF flags IN_AIL
The inode buffer was at 7/20344 when it was removed from the AIL.
xfsaild/pmem1-213314 [001] 6398.023012: xfs_buf_item_relse: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 2 pincount 0 lock 0 flags ASYNC|DONE|STALE|INODES|PAGES caller xfs_buf_item_done+0x31
xfsaild/pmem1-213314 [001] 6398.023012: xfs_buf_rele: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 2 pincount 0 lock 0 flags ASYNC|DONE|STALE|INODES|PAGES caller xfs_buf_item_relse+0x39
.....
Userspace is still running, doing stuff. an fsstress process runs
syncfs() or sync() and we end up in sync_fs_one_sb() which issues
a log force. This pushes on the CIL:
fsstress-213322 [001] 6398.024430: xfs_fs_sync_fs: dev 259:1 m_features 0x20000000019ff6e9 opstate (clean|shutdown|inodegc|blockgc) s_flags 0x70810000 caller sync_fs_one_sb+0x26
fsstress-213322 [001] 6398.024430: xfs_log_force: dev 259:1 lsn 0x0 caller xfs_fs_sync_fs+0x82
fsstress-213322 [001] 6398.024430: xfs_log_force: dev 259:1 lsn 0x5f caller xfs_log_force+0x7c
<...>-194402 [001] 6398.024467: kmem_alloc: size 176 flags 0x14 caller xlog_cil_push_work+0x9f
And the CIL fills up iclogs with pending changes. This picks up
the current tail from the AIL:
<...>-194402 [001] 6398.024497: xlog_iclog_get_space: dev 259:1 state XLOG_STATE_ACTIVE refcnt 1 offset 0 lsn 0x0 flags caller xlog_write+0x149
<...>-194402 [001] 6398.024498: xlog_iclog_switch: dev 259:1 state XLOG_STATE_ACTIVE refcnt 1 offset 0 lsn 0x700005408 flags caller xlog_state_get_iclog_space+0x37e
<...>-194402 [001] 6398.024521: xlog_iclog_release: dev 259:1 state XLOG_STATE_WANT_SYNC refcnt 1 offset 32256 lsn 0x700005408 flags caller xlog_write+0x5f9
<...>-194402 [001] 6398.024522: xfs_log_assign_tail_lsn: dev 259:1 new tail lsn 7/21000, old lsn 7/20344, last sync 7/21448
And it moves the tail of the log to 7/21000 from 7/20344. This
*moves the tail of the log beyond the ICREATE transaction* that was
at 7/20344 and pinned by the inode cluster buffer that was cancelled
above.
....
godown-213341 [008] 6398.027005: xfs_force_shutdown: dev 259:1 tag logerror flags log_io|force_umount file fs/xfs/xfs_fsops.c line_num 500
godown-213341 [008] 6398.027022: console: [ 6397.915406] pmem1: writeback error on inode 12621949, offset 1019904, sector 12968096
godown-213341 [008] 6398.030551: console: [ 6397.919546] XFS (pmem1): Log I/O Error (0x6) detected at xfs_fs_goingdown+0xa3/0xf0 (fs/
And finally the log itself is now shutdown, stopping all further
writes to the log. But this is too late to prevent the corruption
that moving the tail of the log forwards after we start cancelling
writeback causes.
The fundamental problem here is that we are using the wrong shutdown
checks for log items. We've long conflated mount shutdown with log
shutdown state, and I started separating that recently with the
atomic shutdown state changes in commit b36d4651e1 ("xfs: make
forced shutdown processing atomic"). The changes in that commit
series are directly responsible for being able to diagnose this
issue because it clearly separated mount shutdown from log shutdown.
Essentially, once we start cancelling writeback of log items and
removing them from the AIL because the filesystem is shut down, we
*cannot* update the journal because we may have cancelled the items
that pin the tail of the log. That moves the tail of the log
forwards without having written the metadata back, hence we have
corrupt in memory state and writing to the journal propagates that
to the on-disk state.
What commit b36d4651e1 makes clear is that log item state needs to
change relative to log shutdown, not mount shutdown. IOWs, anything
that aborts metadata writeback needs to check log shutdown state
because log items directly affect log consistency. Having them check
mount shutdown state introduces the above race condition where we
cancel metadata writeback before the log shuts down.
To fix this, this patch works through all log items and converts
shutdown checks to use xlog_is_shutdown() rather than
xfs_is_shutdown(), so that we don't start aborting metadata
writeback before we shut off journal writes.
AFAICT, this race condition is a zero day IO error handling bug in
XFS that dates back to the introduction of XLOG_IO_ERROR,
XLOG_STATE_IOERROR and XFS_FORCED_SHUTDOWN back in January 1997.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
