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2025-03-03xfs: allow internal RT devices for zoned modeChristoph Hellwig
Allow creating an RT subvolume on the same device as the main data device. This is mostly used for SMR HDDs where the conventional zones are used for the data device and the sequential write required zones for the zoned RT section. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: define the zoned on-disk formatChristoph Hellwig
Zone file systems reuse the basic RT group enabled XFS file system structure to support a mode where each RT group is always written from start to end and then reset for reuse (after moving out any remaining data). There are few minor but important changes, which are indicated by a new incompat flag: 1) there are no bitmap and summary inodes, thus the /rtgroups/{rgno}.{bitmap,summary} metadir files do not exist and the sb_rbmblocks superblock field must be cleared to zero. 2) there is a new superblock field that specifies the start of an internal RT section. This allows supporting SMR HDDs that have random writable space at the beginning which is used for the XFS data device (which really is the metadata device for this configuration), directly followed by a RT device on the same block device. While something similar could be achieved using dm-linear just having a single device directly consumed by XFS makes handling the file systems a lot easier. 3) Another superblock field that tracks the amount of reserved space (or overprovisioning) that is never used for user capacity, but allows GC to run more smoothly. 4) an overlay of the cowextsize field for the rtrmap inode so that we can persistently track the total amount of rtblocks currently used in a RT group. There is no data structure other than the rmap that tracks used space in an RT group, and this counter is used to decide when a RT group has been entirely emptied, and to select one that is relatively empty if garbage collection needs to be performed. While this counter could be tracked entirely in memory and rebuilt from the rmap at mount time, that would lead to very long mount times with the large number of RT groups implied by the number of hardware zones especially on SMR hard drives with 256MB zone sizes. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: add a xfs_rtrmap_highest_rgbno helperChristoph Hellwig
Add a helper to find the last offset mapped in the rtrmap. This will be used by the zoned code to find out where to start writing again on conventional devices without hardware zone support. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: support XFS_BMAPI_REMAP in xfs_bmap_del_extent_delayChristoph Hellwig
The zone allocator wants to be able to remove a delalloc mapping in the COW fork while keeping the block reservation. To support that pass the flags argument down to xfs_bmap_del_extent_delay and support the XFS_BMAPI_REMAP flag to keep the reservation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: refine the unaligned check for always COW inodes in xfs_file_dio_writeChristoph Hellwig
For always COW inodes we also must check the alignment of each individual iovec segment, as they could end up with different I/Os due to the way bio_iov_iter_get_pages works, and we'd then overwrite an already written block. The existing always_cow sysctl based code doesn't catch this because nothing enforces that blocks aren't rewritten, but for zoned XFS on sequential write required zones this is a hard error. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: skip always_cow inodes in xfs_reflink_trim_around_sharedChristoph Hellwig
xfs_reflink_trim_around_shared tries to find shared blocks in the refcount btree. Always_cow inodes don't have that tree, so don't bother. For the existing always_cow code this is a minor optimization. For the upcoming zoned code that can do COW without the rtreflink code it avoids triggering a NULL pointer dereference. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: move xfs_bmapi_reserve_delalloc to xfs_iomap.cChristoph Hellwig
Delalloc reservations are not supported in userspace, and thus it doesn't make sense to share this helper with xfsprogs.c. Move it to xfs_iomap.c toward the two callers. Note that there rest of the delalloc handling should probably eventually also move out of xfs_bmap.c, but that will require a bit more surgery. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: add a rtg_blocks helperChristoph Hellwig
Shortcut dereferencing the xg_block_count field in the generic group structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: factor out a xfs_rt_check_size helperChristoph Hellwig
Add a helper to check that the last block of a RT device is readable to share the code between mount and growfs. This also adds the mount time overflow check to growfs and improves the error messages. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: reduce metafile reservationsChristoph Hellwig
There is no point in reserving more space than actually available on the data device for the worst case scenario that is unlikely to happen. Reserve at most 1/4th of the data device blocks, which is still a heuristic. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: make metabtree reservations globalChristoph Hellwig
Currently each metabtree inode has it's own space reservation to ensure it can be expanded to the maximum size, mirroring what is done for the AG-based btrees. But unlike the AG-based btrees the metabtree inodes aren't restricted to allocate from a single AG but can use free space form the entire file system. And unlike AG-based btrees where the required reservation shrinks with the available free space due to this, the metabtree reservations for the rtrmap and rtfreflink trees are not bound in any way by the data device free space as they track RT extent allocations. This is not very efficient as it requires a large number of blocks to be set aside that can't be used at all by other btrees. Switch to a model that uses a global pool instead in preparation for reducing the amount of reserved space, which now also removes the overloading of the i_nblocks field for metabtree inodes, which would create problems if metabtree inodes ever had a big enough xattr fork to require xattr blocks outside the inode. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: fixup the metabtree reservation in xrep_reap_metadir_fsblocksChristoph Hellwig
All callers of xrep_reap_metadir_fsblocks need to fix up the metabtree reservation, otherwise they'd leave the reservations in an incoherent state. Move the call to xrep_reset_metafile_resv into xrep_reap_metadir_fsblocks so it always is taken care of, and remove now superfluous helper functions in the callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: trace in-memory freecounter reservationsChristoph Hellwig
Add two tracepoints when the freecounter dips into the reserved pool and when it is entirely out of space. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: support reserved blocks for the rt extent counterChristoph Hellwig
The zoned space allocator will need reserved RT extents for garbage collection and zeroing of partial blocks. Move the resblks related fields into the freecounter array so that they can be used for all counters. Co-developed-by: Hans Holmberg <hans.holmberg@wdc.com> Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: generalize the freespace and reserved blocks handlingChristoph Hellwig
xfs_{add,dec}_freecounter already handles the block and RT extent percpu counters, but it currently hardcodes the passed in counter. Add a freecounter abstraction that uses an enum to designate the counter and add wrappers that hide the actual percpu_counters. This will allow expanding the reserved block handling to the RT extent counter in the next step, and also prepares for adding yet another such counter that can share the code. Both these additions will be needed for the zoned allocator. Also switch the flooring of the frextents counter to 0 in statfs for the rthinherit case to a manual min_t call to match the handling of the fdblocks counter for normal file systems. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03xfs: reflow xfs_dec_freecounterChristoph Hellwig
Let the successful allocation be the main path through the function with exception handling in branches to make the code easier to follow. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03Merge branch 'vfs-6.15.iomap' of ↵Carlos Maiolino
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs into xfs-6.15-merge
2025-02-27Change inode_operations.mkdir to return struct dentry *NeilBrown
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have complete control of sequencing on the actual filesystem (e.g. on a different server) and may find that the inode created for a mkdir request already exists in the icache and dcache by the time the mkdir request returns. For example, if the filesystem is mounted twice the directory could be visible on the other mount before it is on the original mount, and a pair of name_to_handle_at(), open_by_handle_at() calls could instantiate the directory inode with an IS_ROOT() dentry before the first mkdir returns. This means that the dentry passed to ->mkdir() may not be the one that is associated with the inode after the ->mkdir() completes. Some callers need to interact with the inode after the ->mkdir completes and they currently need to perform a lookup in the (rare) case that the dentry is no longer hashed. This lookup-after-mkdir requires that the directory remains locked to avoid races. Planned future patches to lock the dentry rather than the directory will mean that this lookup cannot be performed atomically with the mkdir. To remove this barrier, this patch changes ->mkdir to return the resulting dentry if it is different from the one passed in. Possible returns are: NULL - the directory was created and no other dentry was used ERR_PTR() - an error occurred non-NULL - this other dentry was spliced in This patch only changes file-systems to return "ERR_PTR(err)" instead of "err" or equivalent transformations. Subsequent patches will make further changes to some file-systems to return a correct dentry. Not all filesystems reliably result in a positive hashed dentry: - NFS, cifs, hostfs will sometimes need to perform a lookup of the name to get inode information. Races could result in this returning something different. Note that this lookup is non-atomic which is what we are trying to avoid. Placing the lookup in filesystem code means it only happens when the filesystem has no other option. - kernfs and tracefs leave the dentry negative and the ->revalidate operation ensures that lookup will be called to correctly populate the dentry. This could be fixed but I don't think it is important to any of the users of vfs_mkdir() which look at the dentry. The recommendation to use d_drop();d_splice_alias() is ugly but fits with current practice. A planned future patch will change this. Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27xfs: flag as supporting FOP_DONTCACHEJens Axboe
Read side was already fully supported, and with the write side appropriately punted to the worker queue, all that's needed now is setting FOP_DONTCACHE in the file_operations structure to enable full support for read and write uncached IO. This provides similar benefits to using RWF_DONTCACHE with reads. Testing buffered writes on 32 files: writing bs 65536, uncached 0 1s: 196035MB/sec 2s: 132308MB/sec 3s: 132438MB/sec 4s: 116528MB/sec 5s: 103898MB/sec 6s: 108893MB/sec 7s: 99678MB/sec 8s: 106545MB/sec 9s: 106826MB/sec 10s: 101544MB/sec 11s: 111044MB/sec 12s: 124257MB/sec 13s: 116031MB/sec 14s: 114540MB/sec 15s: 115011MB/sec 16s: 115260MB/sec 17s: 116068MB/sec 18s: 116096MB/sec where it's quite obvious where the page cache filled, and performance dropped from to about half of where it started, settling in at around 115GB/sec. Meanwhile, 32 kswapds were running full steam trying to reclaim pages. Running the same test with uncached buffered writes: writing bs 65536, uncached 1 1s: 198974MB/sec 2s: 189618MB/sec 3s: 193601MB/sec 4s: 188582MB/sec 5s: 193487MB/sec 6s: 188341MB/sec 7s: 194325MB/sec 8s: 188114MB/sec 9s: 192740MB/sec 10s: 189206MB/sec 11s: 193442MB/sec 12s: 189659MB/sec 13s: 191732MB/sec 14s: 190701MB/sec 15s: 191789MB/sec 16s: 191259MB/sec 17s: 190613MB/sec 18s: 191951MB/sec and the behavior is fully predictable, performing the same throughout even after the page cache would otherwise have fully filled with dirty data. It's also about 65% faster, and using half the CPU of the system compared to the normal buffered write. Signed-off-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20250204184047.356762-3-axboe@kernel.dk Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27xfs: flag as supporting FOP_DONTCACHEJens Axboe
Read side was already fully supported, and with the write side appropriately punted to the worker queue, all that's needed now is setting FOP_DONTCACHE in the file_operations structure to enable full support for read and write uncached IO. This provides similar benefits to using RWF_DONTCACHE with reads. Testing buffered writes on 32 files: writing bs 65536, uncached 0 1s: 196035MB/sec 2s: 132308MB/sec 3s: 132438MB/sec 4s: 116528MB/sec 5s: 103898MB/sec 6s: 108893MB/sec 7s: 99678MB/sec 8s: 106545MB/sec 9s: 106826MB/sec 10s: 101544MB/sec 11s: 111044MB/sec 12s: 124257MB/sec 13s: 116031MB/sec 14s: 114540MB/sec 15s: 115011MB/sec 16s: 115260MB/sec 17s: 116068MB/sec 18s: 116096MB/sec where it's quite obvious where the page cache filled, and performance dropped from to about half of where it started, settling in at around 115GB/sec. Meanwhile, 32 kswapds were running full steam trying to reclaim pages. Running the same test with uncached buffered writes: writing bs 65536, uncached 1 1s: 198974MB/sec 2s: 189618MB/sec 3s: 193601MB/sec 4s: 188582MB/sec 5s: 193487MB/sec 6s: 188341MB/sec 7s: 194325MB/sec 8s: 188114MB/sec 9s: 192740MB/sec 10s: 189206MB/sec 11s: 193442MB/sec 12s: 189659MB/sec 13s: 191732MB/sec 14s: 190701MB/sec 15s: 191789MB/sec 16s: 191259MB/sec 17s: 190613MB/sec 18s: 191951MB/sec and the behavior is fully predictable, performing the same throughout even after the page cache would otherwise have fully filled with dirty data. It's also about 65% faster, and using half the CPU of the system compared to the normal buffered write. Signed-off-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20250204184047.356762-3-axboe@kernel.dk Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-25xfs: remove the XBF_STALE check from xfs_buf_rele_cachedChristoph Hellwig
xfs_buf_stale already set b_lru_ref to 0, and thus prevents the buffer from moving to the LRU. Remove the duplicate check. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-25xfs: remove most in-flight buffer accountingChristoph Hellwig
The buffer cache keeps a bt_io_count per-CPU counter to track all in-flight I/O, which is used to ensure no I/O is in flight when unmounting the file system. For most I/O we already keep track of inflight I/O at higher levels: - for synchronous I/O (xfs_buf_read/xfs_bwrite/xfs_buf_delwri_submit), the caller has a reference and waits for I/O completions using xfs_buf_iowait - for xfs_buf_delwri_submit_nowait the only caller (AIL writeback) tracks the log items that the buffer attached to This only leaves only xfs_buf_readahead_map as a submitter of asynchronous I/O that is not tracked by anything else. Replace the bt_io_count per-cpu counter with a more specific bt_readahead_count counter only tracking readahead I/O. This allows to simply increment it when submitting readahead I/O and decrementing it when it completed, and thus simplify xfs_buf_rele and remove the needed for the XBF_NO_IOACCT flags and the XFS_BSTATE_IN_FLIGHT buffer state. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-25xfs: decouple buffer readahead from the normal buffer read pathChristoph Hellwig
xfs_buf_readahead_map is the only caller of xfs_buf_read_map and thus _xfs_buf_read that is not synchronous. Split it from xfs_buf_read_map so that the asynchronous path is self-contained and the now purely synchronous xfs_buf_read_map / _xfs_buf_read implementation can be simplified. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-25xfs: reduce context switches for synchronous buffered I/OChristoph Hellwig
Currently all metadata I/O completions happen in the m_buf_workqueue workqueue. But for synchronous I/O (i.e. all buffer reads) there is no need for that, as there always is a called in process context that is waiting for the I/O. Factor out the guts of xfs_buf_ioend into a separate helper and call it from xfs_buf_iowait to avoid a double an extra context switch to the workqueue. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-14xfs: flush inodegc before swaponChristoph Hellwig
Fix the brand new xfstest that tries to swapon on a recently unshared file and use the chance to document the other bit of magic in this function. The big comment is taken from a mailinglist post by Dave Chinner. Fixes: 5e672cd69f0a53 ("xfs: introduce xfs_inodegc_push()") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-14xfs: rename xfs_iomap_swapfile_activate to xfs_vm_swap_activateChristoph Hellwig
Match the method name and the naming convention or address_space operations. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-14xfs: Do not allow norecovery mount with quotacheckCarlos Maiolino
Mounting a filesystem that requires quota state changing will generate a transaction. We already check for a read-only device; we should do that for norecovery too. A quotacheck on a norecovery mount, and with the right log size, will cause the mount process to hang on: [<0>] xlog_grant_head_wait+0x5d/0x2a0 [xfs] [<0>] xlog_grant_head_check+0x112/0x180 [xfs] [<0>] xfs_log_reserve+0xe3/0x260 [xfs] [<0>] xfs_trans_reserve+0x179/0x250 [xfs] [<0>] xfs_trans_alloc+0x101/0x260 [xfs] [<0>] xfs_sync_sb+0x3f/0x80 [xfs] [<0>] xfs_qm_mount_quotas+0xe3/0x2f0 [xfs] [<0>] xfs_mountfs+0x7ad/0xc20 [xfs] [<0>] xfs_fs_fill_super+0x762/0xa50 [xfs] [<0>] get_tree_bdev_flags+0x131/0x1d0 [<0>] vfs_get_tree+0x26/0xd0 [<0>] vfs_cmd_create+0x59/0xe0 [<0>] __do_sys_fsconfig+0x4e3/0x6b0 [<0>] do_syscall_64+0x82/0x160 [<0>] entry_SYSCALL_64_after_hwframe+0x76/0x7e This is caused by a transaction running with bogus initialized head/tail I initially hit this while running generic/050, with random log sizes, but I managed to reproduce it reliably here with the steps below: mkfs.xfs -f -lsize=1025M -f -b size=4096 -m crc=1,reflink=1,rmapbt=1, -i sparse=1 /dev/vdb2 > /dev/null mount -o usrquota,grpquota,prjquota /dev/vdb2 /mnt xfs_io -x -c 'shutdown -f' /mnt umount /mnt mount -o ro,norecovery,usrquota,grpquota,prjquota /dev/vdb2 /mnt Last mount hangs up As we add yet another validation if quota state is changing, this also add a new helper named xfs_qm_validate_state_change(), factoring the quota state changes out of xfs_qm_newmount() to reduce cluttering within it. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-14xfs: do not check NEEDSREPAIR if ro,norecovery mount.Lukas Herbolt
If there is corrutpion on the filesystem andxfs_repair fails to repair it. The last resort of getting the data is to use norecovery,ro mount. But if the NEEDSREPAIR is set the filesystem cannot be mounted. The flag must be cleared out manually using xfs_db, to get access to what left over of the corrupted fs. Signed-off-by: Lukas Herbolt <lukas@herbolt.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-14xfs: fix data fork format filtering during inode repairDarrick J. Wong
Coverity noticed that xrep_dinode_bad_metabt_fork never runs because XFS_DINODE_FMT_META_BTREE is always filtered out in the mode selection switch of xrep_dinode_check_dfork. Metadata btrees are allowed only in the data forks of regular files, so add this case explicitly. I guess this got fubard during a refactoring prior to 6.13 and I didn't notice until now. :/ Coverity-id: 1617714 Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-14xfs: fix online repair probing when CONFIG_XFS_ONLINE_REPAIR=nDarrick J. Wong
I received a report from the release engineering side of the house that xfs_scrub without the -n flag (aka fix it mode) would try to fix a broken filesystem even on a kernel that doesn't have online repair built into it: # xfs_scrub -dTvn /mnt/test EXPERIMENTAL xfs_scrub program in use! Use at your own risk! Phase 1: Find filesystem geometry. /mnt/test: using 1 threads to scrub. Phase 1: Memory used: 132k/0k (108k/25k), time: 0.00/ 0.00/ 0.00s <snip> Phase 4: Repair filesystem. <snip> Info: /mnt/test/some/victimdir directory entries: Attempting repair. (repair.c line 351) Corruption: /mnt/test/some/victimdir directory entries: Repair unsuccessful; offline repair required. (repair.c line 204) Source: https://blogs.oracle.com/linux/post/xfs-online-filesystem-repair It is strange that xfs_scrub doesn't refuse to run, because the kernel is supposed to return EOPNOTSUPP if we actually needed to run a repair, and xfs_io's repair subcommand will perror that. And yet: # xfs_io -x -c 'repair probe' /mnt/test # The first problem is commit dcb660f9222fd9 (4.15) which should have had xchk_probe set the CORRUPT OFLAG so that any of the repair machinery will get called at all. It turns out that some refactoring that happened in the 6.6-6.8 era broke the operation of this corner case. What we *really* want to happen is that all the predicates that would steer xfs_scrub_metadata() towards calling xrep_attempt() should function the same way that they do when repair is compiled in; and then xrep_attempt gets to return the fatal EOPNOTSUPP error code that causes the probe to fail. Instead, commit 8336a64eb75cba (6.6) started the failwhale swimming by hoisting OFLAG checking logic into a helper whose non-repair stub always returns false, causing scrub to return "repair not needed" when in fact the repair is not supported. Prior to that commit, the oflag checking that was open-coded in scrub.c worked correctly. Similarly, in commit 4bdfd7d15747b1 (6.8) we hoisted the IFLAG_REPAIR and ALREADY_FIXED logic into a helper whose non-repair stub always returns false, so we never enter the if test body that would have called xrep_attempt, let alone fail to decode the OFLAGs correctly. The final insult (yes, we're doing The Naked Gun now) is commit 48a72f60861f79 (6.8) in which we hoisted the "are we going to try a repair?" predicate into yet another function with a non-repair stub always returns false. Fix xchk_probe to trigger xrep_probe if repair is enabled, or return EOPNOTSUPP directly if it is not. For all the other scrub types, we need to fix the header predicates so that the ->repair functions (which are all xrep_notsupported) get called to return EOPNOTSUPP. Commit 48a72 is tagged here because the scrub code prior to LTS 6.12 are incomplete and not worth patching. Reported-by: David Flynn <david.flynn@oracle.com> Cc: <stable@vger.kernel.org> # v6.8 Fixes: 8336a64eb75c ("xfs: don't complain about unfixed metadata when repairs were injected") Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-02-06iomap: pass private data to iomap_truncate_pageChristoph Hellwig
Allow the file system to pass private data which can be used by the iomap_begin and iomap_end methods through the private pointer in the iomap_iter structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250206064035.2323428-12-hch@lst.de Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-06iomap: pass private data to iomap_zero_rangeChristoph Hellwig
Allow the file system to pass private data which can be used by the iomap_begin and iomap_end methods through the private pointer in the iomap_iter structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250206064035.2323428-11-hch@lst.de Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-06iomap: pass private data to iomap_page_mkwriteChristoph Hellwig
Allow the file system to pass private data which can be used by the iomap_begin and iomap_end methods through the private pointer in the iomap_iter structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250206064035.2323428-10-hch@lst.de Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-06iomap: simplify io_flags and io_type in struct iomap_ioendChristoph Hellwig
The ioend fields for distinct types of I/O are a bit complicated. Consolidate them into a single io_flag field with it's own flags decoupled from the iomap flags. This also prepares for adding a new flag that is unrelated to both of the iomap namespaces. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250206064035.2323428-3-hch@lst.de Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-06iomap: allow the file system to submit the writeback biosChristoph Hellwig
Change ->prepare_ioend to ->submit_ioend and require file systems that implement it to submit the bio. This is needed for file systems that do their own work on the bios before submitting them to the block layer like btrfs or zoned xfs. To make this easier also pass the writeback context to the method. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250206064035.2323428-2-hch@lst.de Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-03Merge tag 'xfs-fixes-6.14-rc2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds
Pull xfs bug fixes from Carlos Maiolino: "A few fixes for XFS, but the most notable one is: - xfs: remove xfs_buf_cache.bc_lock which has been hit by different persons including syzbot" * tag 'xfs-fixes-6.14-rc2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: remove xfs_buf_cache.bc_lock xfs: Add error handling for xfs_reflink_cancel_cow_range xfs: Propagate errors from xfs_reflink_cancel_cow_range in xfs_dax_write_iomap_end xfs: don't call remap_verify_area with sb write protection held xfs: remove an out of data comment in _xfs_buf_alloc xfs: fix the entry condition of exact EOF block allocation optimization
2025-01-28treewide: const qualify ctl_tables where applicableJoel Granados
Add the const qualifier to all the ctl_tables in the tree except for watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls, loadpin_sysctl_table and the ones calling register_net_sysctl (./net, drivers/inifiniband dirs). These are special cases as they use a registration function with a non-const qualified ctl_table argument or modify the arrays before passing them on to the registration function. Constifying ctl_table structs will prevent the modification of proc_handler function pointers as the arrays would reside in .rodata. This is made possible after commit 78eb4ea25cd5 ("sysctl: treewide: constify the ctl_table argument of proc_handlers") constified all the proc_handlers. Created this by running an spatch followed by a sed command: Spatch: virtual patch @ depends on !(file in "net") disable optional_qualifier @ identifier table_name != { watchdog_hardlockup_sysctl, iwcm_ctl_table, ucma_ctl_table, memory_allocation_profiling_sysctls, loadpin_sysctl_table }; @@ + const struct ctl_table table_name [] = { ... }; sed: sed --in-place \ -e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \ kernel/utsname_sysctl.c Reviewed-by: Song Liu <song@kernel.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> # for kernel/trace/ Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> # SCSI Reviewed-by: Darrick J. Wong <djwong@kernel.org> # xfs Acked-by: Jani Nikula <jani.nikula@intel.com> Acked-by: Corey Minyard <cminyard@mvista.com> Acked-by: Wei Liu <wei.liu@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Bill O'Donnell <bodonnel@redhat.com> Acked-by: Baoquan He <bhe@redhat.com> Acked-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Acked-by: Anna Schumaker <anna.schumaker@oracle.com> Signed-off-by: Joel Granados <joel.granados@kernel.org>
2025-01-28xfs: remove xfs_buf_cache.bc_lockChristoph Hellwig
xfs_buf_cache.bc_lock serializes adding buffers to and removing them from the hashtable. But as the rhashtable code already uses fine grained internal locking for inserts and removals the extra protection isn't actually required. It also happens to fix a lock order inversion vs b_lock added by the recent lookup race fix. Fixes: ee10f6fcdb96 ("xfs: fix buffer lookup vs release race") Reported-by: Lai, Yi <yi1.lai@linux.intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-01-27xfs: Add error handling for xfs_reflink_cancel_cow_rangeWentao Liang
In xfs_inactive(), xfs_reflink_cancel_cow_range() is called without error handling, risking unnoticed failures and inconsistent behavior compared to other parts of the code. Fix this issue by adding an error handling for the xfs_reflink_cancel_cow_range(), improving code robustness. Fixes: 6231848c3aa5 ("xfs: check for cow blocks before trying to clear them") Cc: stable@vger.kernel.org # v4.17 Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-01-27xfs: Propagate errors from xfs_reflink_cancel_cow_range in ↵Wentao Liang
xfs_dax_write_iomap_end In xfs_dax_write_iomap_end(), directly return the result of xfs_reflink_cancel_cow_range() when !written, ensuring proper error propagation and improving code robustness. Fixes: ea6c49b784f0 ("xfs: support CoW in fsdax mode") Cc: stable@vger.kernel.org # v6.0 Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-01-26Merge tag 'mm-stable-2025-01-26-14-59' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "The various patchsets are summarized below. Plus of course many indivudual patches which are described in their changelogs. - "Allocate and free frozen pages" from Matthew Wilcox reorganizes the page allocator so we end up with the ability to allocate and free zero-refcount pages. So that callers (ie, slab) can avoid a refcount inc & dec - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use large folios other than PMD-sized ones - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and fixes for this small built-in kernel selftest - "mas_anode_descend() related cleanup" from Wei Yang tidies up part of the mapletree code - "mm: fix format issues and param types" from Keren Sun implements a few minor code cleanups - "simplify split calculation" from Wei Yang provides a few fixes and a test for the mapletree code - "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes continues the work of moving vma-related code into the (relatively) new mm/vma.c - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David Hildenbrand cleans up and rationalizes handling of gfp flags in the page allocator - "readahead: Reintroduce fix for improper RA window sizing" from Jan Kara is a second attempt at fixing a readahead window sizing issue. It should reduce the amount of unnecessary reading - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng addresses an issue where "huge" amounts of pte pagetables are accumulated: https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/ Qi's series addresses this windup by synchronously freeing PTE memory within the context of madvise(MADV_DONTNEED) - "selftest/mm: Remove warnings found by adding compiler flags" from Muhammad Usama Anjum fixes some build warnings in the selftests code when optional compiler warnings are enabled - "mm: don't use __GFP_HARDWALL when migrating remote pages" from David Hildenbrand tightens the allocator's observance of __GFP_HARDWALL - "pkeys kselftests improvements" from Kevin Brodsky implements various fixes and cleanups in the MM selftests code, mainly pertaining to the pkeys tests - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to estimate application working set size - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn provides some cleanups to memcg's hugetlb charging logic - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song removes the global swap cgroup lock. A speedup of 10% for a tmpfs-based kernel build was demonstrated - "zram: split page type read/write handling" from Sergey Senozhatsky has several fixes and cleaups for zram in the area of zram_write_page(). A watchdog softlockup warning was eliminated - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky cleans up the pagetable destructor implementations. A rare use-after-free race is fixed - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes simplifies and cleans up the debugging code in the VMA merging logic - "Account page tables at all levels" from Kevin Brodsky cleans up and regularizes the pagetable ctor/dtor handling. This results in improvements in accounting accuracy - "mm/damon: replace most damon_callback usages in sysfs with new core functions" from SeongJae Park cleans up and generalizes DAMON's sysfs file interface logic - "mm/damon: enable page level properties based monitoring" from SeongJae Park increases the amount of information which is presented in response to DAMOS actions - "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes DAMON's long-deprecated debugfs interfaces. Thus the migration to sysfs is completed - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter Xu cleans up and generalizes the hugetlb reservation accounting - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino removes a never-used feature of the alloc_pages_bulk() interface - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park extends DAMOS filters to support not only exclusion (rejecting), but also inclusion (allowing) behavior - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi introduces a new memory descriptor for zswap.zpool that currently overlaps with struct page for now. This is part of the effort to reduce the size of struct page and to enable dynamic allocation of memory descriptors - "mm, swap: rework of swap allocator locks" from Kairui Song redoes and simplifies the swap allocator locking. A speedup of 400% was demonstrated for one workload. As was a 35% reduction for kernel build time with swap-on-zram - "mm: update mips to use do_mmap(), make mmap_region() internal" from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that mmap_region() can be made MM-internal - "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU regressions and otherwise improves MGLRU performance - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park updates DAMON documentation - "Cleanup for memfd_create()" from Isaac Manjarres does that thing - "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand provides various cleanups in the areas of hugetlb folios, THP folios and migration - "Uncached buffered IO" from Jens Axboe implements the new RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache reading and writing. To permite userspace to address issues with massive buildup of useless pagecache when reading/writing fast devices - "selftests/mm: virtual_address_range: Reduce memory" from Thomas Weißschuh fixes and optimizes some of the MM selftests" * tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm/compaction: fix UBSAN shift-out-of-bounds warning s390/mm: add missing ctor/dtor on page table upgrade kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags() tools: add VM_WARN_ON_VMG definition mm/damon/core: use str_high_low() helper in damos_wmark_wait_us() seqlock: add missing parameter documentation for raw_seqcount_try_begin() mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh mm/page_alloc: remove the incorrect and misleading comment zram: remove zcomp_stream_put() from write_incompressible_page() mm: separate move/undo parts from migrate_pages_batch() mm/kfence: use str_write_read() helper in get_access_type() selftests/mm/mkdirty: fix memory leak in test_uffdio_copy() kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags() selftests/mm: virtual_address_range: avoid reading from VM_IO mappings selftests/mm: vm_util: split up /proc/self/smaps parsing selftests/mm: virtual_address_range: unmap chunks after validation selftests/mm: virtual_address_range: mmap() without PROT_WRITE selftests/memfd/memfd_test: fix possible NULL pointer dereference mm: add FGP_DONTCACHE folio creation flag mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue ...
2025-01-25mm: alloc_pages_bulk: rename APILuiz Capitulino
The previous commit removed the page_list argument from alloc_pages_bulk_noprof() along with the alloc_pages_bulk_list() function. Now that only the *_array() flavour of the API remains, we can do the following renaming (along with the _noprof() ones): alloc_pages_bulk_array -> alloc_pages_bulk alloc_pages_bulk_array_mempolicy -> alloc_pages_bulk_mempolicy alloc_pages_bulk_array_node -> alloc_pages_bulk_node Link: https://lkml.kernel.org/r/275a3bbc0be20fbe9002297d60045e67ab3d4ada.1734991165.git.luizcap@redhat.com Signed-off-by: Luiz Capitulino <luizcap@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Yunsheng Lin <linyunsheng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-24xfs: don't call remap_verify_area with sb write protection heldChristoph Hellwig
The XFS_IOC_EXCHANGE_RANGE ioctl with the XFS_EXCHANGE_RANGE_TO_EOF flag operates on a range bounded by the end of the file. This means the actual amount of blocks exchanged is derived from the inode size, which is only stable with the IOLOCK (i_rwsem) held. Do that, it currently calls remap_verify_area from inside the sb write protection which nests outside the IOLOCK. But this makes fsnotify_file_area_perm which is called from remap_verify_area unhappy when the kernel is built with lockdep and the recently added CONFIG_FANOTIFY_ACCESS_PERMISSIONS option. Fix this by always calling remap_verify_area before taking the write protection, and passing a 0 size to remap_verify_area similar to the FICLONE/FICLONERANGE ioctls when they are asked to clone until the file end. (Note: the size argument gets passed to fsnotify_file_area_perm, but then isn't actually used there). Fixes: 9a64d9b3109d ("xfs: introduce new file range exchange ioctl") Cc: <stable@vger.kernel.org> # v6.10 Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-01-24xfs: remove an out of data comment in _xfs_buf_allocChristoph Hellwig
There hasn't been anything like an io_length for a long time. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-01-24xfs: fix the entry condition of exact EOF block allocation optimizationJinliang Zheng
When we call create(), lseek() and write() sequentially, offset != 0 cannot be used as a judgment condition for whether the file already has extents. Furthermore, when xfs_bmap_adjacent() has not given a better blkno, it is not necessary to use exact EOF block allocation. Suggested-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-01-23Merge tag 'fsnotify_hsm_for_v6.14-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull fsnotify pre-content notification support from Jan Kara: "This introduces a new fsnotify event (FS_PRE_ACCESS) that gets generated before a file contents is accessed. The event is synchronous so if there is listener for this event, the kernel waits for reply. On success the execution continues as usual, on failure we propagate the error to userspace. This allows userspace to fill in file content on demand from slow storage. The context in which the events are generated has been picked so that we don't hold any locks and thus there's no risk of a deadlock for the userspace handler. The new pre-content event is available only for users with global CAP_SYS_ADMIN capability (similarly to other parts of fanotify functionality) and it is an administrator responsibility to make sure the userspace event handler doesn't do stupid stuff that can DoS the system. Based on your feedback from the last submission, fsnotify code has been improved and now file->f_mode encodes whether pre-content event needs to be generated for the file so the fast path when nobody wants pre-content event for the file just grows the additional file->f_mode check. As a bonus this also removes the checks whether the old FS_ACCESS event needs to be generated from the fast path. Also the place where the event is generated during page fault has been moved so now filemap_fault() generates the event if and only if there is no uptodate folio in the page cache. Also we have dropped FS_PRE_MODIFY event as current real-world users of the pre-content functionality don't really use it so let's start with the minimal useful feature set" * tag 'fsnotify_hsm_for_v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (21 commits) fanotify: Fix crash in fanotify_init(2) fs: don't block write during exec on pre-content watched files fs: enable pre-content events on supported file systems ext4: add pre-content fsnotify hook for DAX faults btrfs: disable defrag on pre-content watched files xfs: add pre-content fsnotify hook for DAX faults fsnotify: generate pre-content permission event on page fault mm: don't allow huge faults for files with pre content watches fanotify: disable readahead if we have pre-content watches fanotify: allow to set errno in FAN_DENY permission response fanotify: report file range info with pre-content events fanotify: introduce FAN_PRE_ACCESS permission event fsnotify: generate pre-content permission event on truncate fsnotify: pass optional file access range in pre-content event fsnotify: introduce pre-content permission events fanotify: reserve event bit of deprecated FAN_DIR_MODIFY fanotify: rename a misnamed constant fanotify: don't skip extra event info if no info_mode is set fsnotify: check if file is actually being watched for pre-content events on open fsnotify: opt-in for permission events at file open time ...
2025-01-23Merge tag 'xfs-merge-6.14' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds
Pull XFS updates from Carlos Maiolino: "This is mostly focused on the implementation of reflink and reverse-mapping support for XFS's real-time devices. It also includes several bugfixes. - Implement reflink support for the realtime device - Implement reverse-mapping support for the realtime device - Several bug fixes and cleanups" * tag 'xfs-merge-6.14' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (121 commits) xfs: fix buffer lookup vs release race xfs: check for dead buffers in xfs_buf_find_insert xfs: add a b_iodone callback to struct xfs_buf xfs: move b_li_list based retry handling to common code xfs: simplify xfsaild_resubmit_item xfs: always complete the buffer inline in xfs_buf_submit xfs: remove the extra buffer reference in xfs_buf_submit xfs: move invalidate_kernel_vmap_range to xfs_buf_ioend xfs: simplify buffer I/O submission xfs: move in-memory buftarg handling out of _xfs_buf_ioapply xfs: move write verification out of _xfs_buf_ioapply xfs: remove xfs_buf_delwri_submit_buffers xfs: simplify xfs_buf_delwri_pushbuf xfs: move xfs_buf_iowait out of (__)xfs_buf_submit xfs: remove the incorrect comment about the b_pag field xfs: remove the incorrect comment above xfs_buf_free_maps xfs: fix a double completion for buffers on in-memory targets xfs/libxfs: replace kmalloc() and memcpy() with kmemdup() xfs: constify feature checks xfs: refactor xfs_fs_statfs ...
2025-01-20Merge tag 'vfs-6.14-rc1.statx.dio' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs direct-io updates from Christian Brauner: "File systems that write out of place usually require different alignment for direct I/O writes than what they can do for reads. Add a separate dio read align field to statx, as many out of place write file systems can easily do reads aligned to the device sector size, but require bigger alignment for writes. This is usually papered over by falling back to buffered I/O for smaller writes and doing read-modify-write cycles, but performance for this sucks, so applications benefit from knowing the actual write alignment" * tag 'vfs-6.14-rc1.statx.dio' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: xfs: report larger dio alignment for COW inodes xfs: report the correct read/write dio alignment for reflinked inodes xfs: cleanup xfs_vn_getattr fs: add STATX_DIO_READ_ALIGN fs: reformat the statx definition
2025-01-16xfs: fix buffer lookup vs release raceChristoph Hellwig
Since commit 298f34224506 ("xfs: lockless buffer lookup") the buffer lookup fastpath is done without a hash-wide lock (then pag_buf_lock, now bc_lock) and only under RCU protection. But this means that nothing serializes lookups against the temporary 0 reference count for buffers that are added to the LRU after dropping the last regular reference, and a concurrent lookup would fail to find them. Fix this by doing all b_hold modifications under b_lock. We're already doing this for release so this "only" ~ doubles the b_lock round trips. We'll later look into the lockref infrastructure to optimize the number of lock round trips again. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-01-16xfs: check for dead buffers in xfs_buf_find_insertChristoph Hellwig
Commit 32dd4f9c506b ("xfs: remove a superflous hash lookup when inserting new buffers") converted xfs_buf_find_insert to use rhashtable_lookup_get_insert_fast and thus an operation that returns the existing buffer when an insert would duplicate the hash key. But this code path misses the check for a buffer with a reference count of zero, which could lead to reusing an about to be freed buffer. Fix this by using the same atomic_inc_not_zero pattern as xfs_buf_insert. Fixes: 32dd4f9c506b ("xfs: remove a superflous hash lookup when inserting new buffers") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Cc: stable@vger.kernel.org # v6.0 Signed-off-by: Carlos Maiolino <cem@kernel.org>