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2024-02-22xfs: create a helper to count per-device inode block usageDarrick J. Wong
Create a helper to compute the number of blocks that a file has allocated from the data realtime volumes. This patch was split out to reduce the size of the upcoming quotacheck patch. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: create a xchk_trans_alloc_empty helper for scrubDarrick J. Wong
Create a helper to initialize empty transactions on behalf of a scrub operation. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: report the health of quota countsDarrick J. Wong
Report the health of quota counts. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: repair file modes by scanning for a dirent pointing to usDarrick J. Wong
Repair might encounter an inode with a totally garbage i_mode. To fix this problem, we have to figure out if the file was a regular file, a directory, or a special file. One way to figure this out is to check if there are any directories with entries pointing down to the busted file. This patch recovers the file mode by scanning every directory entry on the filesystem to see if there are any that point to the busted file. If the ftype of all such dirents are consistent, the mode is recovered from the ftype. If no dirents are found, the file becomes a regular file. In all cases, ACLs are canceled and the file is made accessible only by root. A previous patch attempted to guess the mode by reading the beginning of the file data. This was rejected by Christoph on the grounds that we cannot trust user-controlled data blocks. Users do not have direct control over the ondisk contents of directory entries, so this method should be much safer. If all the dirents have the same ftype, then we can translate that back into an S_IFMT flag and fix the file. If not, reset the mode to S_IFREG. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: create a macro for decoding ftypes in tracepointsDarrick J. Wong
Create the XFS_DIR3_FTYPE_STR macro so that we can report ftype as strings instead of numbers in tracepoints. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: create a predicate to determine if two xfs_names are the sameDarrick J. Wong
Create a simple predicate to determine if two xfs_names are the same objects or have the exact same name. The comparison is always case sensitive. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: create a static name for the dot entry tooDarrick J. Wong
Create an xfs_name_dot object so that upcoming scrub code can compare against that. Offline repair already has such an object, so we're really just hoisting it to the kernel. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: iscan batching should handle unallocated inodes tooDarrick J. Wong
The inode scanner tries to reduce contention on the AGI header buffer lock by grabbing references to consecutive allocated inodes. Batching stops as soon as we encounter an unallocated inode. This is unfortunate because in the worst case performance collapses to the old "one at a time" behavior if every other inode is free. This is correct behavior, but we could do better. Unallocated inodes by definition have nothing to scan, which means the iscan can ignore them as long as someone ensures that the scan data will reflect another thread allocating the inode and adding interesting metadata to that inode. That mechanism is, of course, the live update hooks. Therefore, extend the batching mechanism to track unallocated inodes adjacent to the scan cursor. The _want_live_update predicate can tell the caller's live update hook to incorporate all live updates to what the scanner thinks is an unallocated inode if (after dropping the AGI) some other thread allocates one of those inodes and begins using it. Note that we cannot just copy the ir_free bitmap into the scan cursor because the batching stops if iget says the inode is in an intermediate state (e.g. on the inactivation list) and cannot be igrabbed. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: cache a bunch of inodes for repair scansDarrick J. Wong
After observing xfs_scrub taking forever to rebuild parent pointers on a pptrs enabled filesystem, I decided to profile what the system was doing. It turns out that when there are a lot of threads trying to scan the filesystem, most of our time is spent contending on AGI buffer locks. Given that we're walking the inobt records anyway, we can often tell ahead of time when there's a bunch of (up to 64) consecutive inodes that we could grab all at once. Do this to amortize the cost of taking the AGI lock across as many inodes as we possibly can. On the author's system this seems to improve parallel throughput from barely one and a half cores to slightly sublinear scaling. The obvious antipattern here of course is where the freemask has every other bit set (e.g. all 0xA's) Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: stagger the starting AG of scrub iscans to reduce contentionDarrick J. Wong
Online directory and parent repairs on parent-pointer equipped filesystems have shown that starting a large number of parallel iscans causes a lot of AGI buffer contention. Try to reduce this by making it so that iscans scan wrap around the end of the filesystem, and using a rotor to stagger where each scanner begins. Surprisingly, this boosts CPU utilization (on the author's test machines) from effectively single-threaded to 160%. Not great, but see the next patch. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: allow scrub to hook metadata updates in other writersDarrick J. Wong
Certain types of filesystem metadata can only be checked by scanning every file in the entire filesystem. Specific examples of this include quota counts, file link counts, and reverse mappings of file extents. Directory and parent pointer reconstruction may also fall into this category. File scanning is much trickier than scanning AG metadata because we have to take inode locks in the same order as the rest of [VX]FS, we can't be holding buffer locks when we do that, and scanning the whole filesystem takes time. Earlier versions of the online repair patchset relied heavily on fsfreeze as a means to quiesce the filesystem so that we could take locks in the proper order without worrying about concurrent updates from other writers. Reviewers of those patches opined that freezing the entire fs to check and repair something was not sufficiently better than unmounting to run fsck offline. I don't agree with that 100%, but the message was clear: find a way to repair things that minimizes the quiet period where nobody can write to the filesystem. Generally, building btree indexes online can be split into two phases: a collection phase where we compute the records that will be put into the new btree; and a construction phase, where we construct the physical btree blocks and persist them. While it's simple to hold resource locks for the entirety of the two phases to ensure that the new index is consistent with the rest of the system, we don't need to hold resource locks during the collection phase if we have a means to receive live updates of other work going on elsewhere in the system. The goal of this patch, then, is to enable online fsck to learn about metadata updates going on in other threads while it constructs a shadow copy of the metadata records to verify or correct the real metadata. To minimize the overhead when online fsck isn't running, we use srcu notifiers because they prioritize fast access to the notifier call chain (particularly when the chain is empty) at a cost to configuring notifiers. Online fsck should be relatively infrequent, so this is acceptable. The intended usage model is fairly simple. Code that modifies a metadata structure of interest should declare a xfs_hook_chain structure in some well defined place, and call xfs_hook_call whenever an update happens. Online fsck code should define a struct notifier_block and use xfs_hook_add to attach the block to the chain, along with a function to be called. This function should synchronize with the fsck scanner to update whatever in-memory data the scanner is collecting. When finished, xfs_hook_del removes the notifier from the list and waits for them all to complete. Originally, I selected srcu notifiers over blocking notifiers to implement live hooks because they seemed to have fewer impacts to scalability. The per-call cost of srcu_notifier_call_chain is higher (19ns) than blocking_notifier_ (4ns) in the single threaded case, but blocking notifiers use an rwsem to stabilize the list. Cacheline bouncing for that rwsem is costly to runtime code when there are a lot of CPUs running regular filesystem operations. If there are no hooks installed, this is a total waste of CPU time. Therefore, I stuck with srcu notifiers, despite trading off single threaded performance for multithreaded performance. I also wasn't thrilled with the very high teardown time for srcu notifiers, since the caller has to wait for the next rcu grace period. This can take a long time if there are a lot of CPUs. Then I discovered the jump label implementation of static keys. Jump labels use kernel code patching to replace a branch with a nop sled when the key is disabled. IOWs, they can eliminate the overhead of _call_chain when there are no hooks enabled. This makes blocking notifiers competitive again -- scrub runs faster because teardown of the chain is a lot cheaper, and runtime code only pays the rwsem locking overhead when scrub is actually running. With jump labels enabled, calls to empty notifier chains are elided from the call sites when there are no hooks registered, which means that the overhead is 0.36ns when fsck is not running. This is perfect for most of the architectures that XFS is expected to run on (e.g. x86, powerpc, arm64, s390x, riscv). For architectures that don't support jump labels (e.g. m68k) the runtime overhead of checking the static key is an atomic counter read. This isn't great, but it's still cheaper than taking a shared rwsem. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: implement live inode scan for scrubDarrick J. Wong
This patch implements a live file scanner for online fsck functions that require the ability to walk a filesystem to gather metadata records and stay informed about metadata changes to files that have already been visited. The iscan structure consists of two inode number cursors: one to track which inode we want to visit next, and a second one to track which inodes have already been visited. This second cursor is key to capturing live updates to files previously scanned while the main thread continues scanning -- any inode greater than this value hasn't been scanned and can go on its way; any other update must be incorporated into the collected data. It is critical for the scanning thraad to hold exclusive access on the inode until after marking the inode visited. This new code is a separate patch from the patchsets adding callers for the sake of enabling the author to move patches around his tree with ease. The intended usage model for this code is roughly: xchk_iscan_start(iscan, 0, 0); while ((error = xchk_iscan_iter(sc, iscan, &ip)) == 1) { xfs_ilock(ip, ...); /* capture inode metadata */ xchk_iscan_mark_visited(iscan, ip); xfs_iunlock(ip, ...); xfs_irele(ip); } xchk_iscan_stop(iscan); if (error) return error; Hook functions for live updates can then do: if (xchk_iscan_want_live_update(...)) /* update the captured inode metadata */ Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: speed up xfs_iwalk_adjust_start a little bitDarrick J. Wong
Replace the open-coded loop that recomputes freecount with a single call to a bit weight function. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-21xfs: fix SEEK_HOLE/DATA for regions with active COW extentsDave Chinner
A data corruption problem was reported by CoreOS image builders when using reflink based disk image copies and then converting them to qcow2 images. The converted images failed the conversion verification step, and it was isolated down to the fact that qemu-img uses SEEK_HOLE/SEEK_DATA to find the data it is supposed to copy. The reproducer allowed me to isolate the issue down to a region of the file that had overlapping data and COW fork extents, and the problem was that the COW fork extent was being reported in it's entirity by xfs_seek_iomap_begin() and so skipping over the real data fork extents in that range. This was somewhat hidden by the fact that 'xfs_bmap -vvp' reported all the extents correctly, and reading the file completely (i.e. not using seek to skip holes) would map the file correctly and all the correct data extents are read. Hence the problem is isolated to just the xfs_seek_iomap_begin() implementation. Instrumentation with trace_printk made the problem obvious: we are passing the wrong length to xfs_trim_extent() in xfs_seek_iomap_begin(). We are passing the end_fsb, not the maximum length of the extent we want to trim the map too. Hence the COW extent map never gets trimmed to the start of the next data fork extent, and so the seek code treats the entire COW fork extent as unwritten and skips entirely over the data fork extents in that range. Link: https://github.com/coreos/coreos-assembler/issues/3728 Fixes: 60271ab79d40 ("xfs: fix SEEK_DATA for speculative COW fork preallocation") Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: remove xfile_{get,put}_pageDarrick J. Wong
These functions aren't used anymore, so get rid of them. Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: convert xfarray_pagesort to deal with large foliosDarrick J. Wong
Convert xfarray_pagesort to handle large folios by introducing a new xfile_get_folio routine that can return a folio of arbitrary size, and using heapsort on the full folio. This also corrects an off-by-one bug in the calculation of len in xfarray_pagesort that was papered over by xfarray_want_pagesort. Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: fix a comment in xfarray.cChristoph Hellwig
xfiles are shmem files, not memfds. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: remove xfarray_sortinfo.page_kaddrChristoph Hellwig
Now that xfile pages don't need kmapping, there is no need to cache the kernel virtual address for them. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: add file_{get,put}_folioDarrick J. Wong
Add helper similar to file_{get,set}_page, but which deal with folios and don't allocate new folio unless explicitly asked to, which map to shmem_get_folio instead of calling into the aops. Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: use shmem_get_folio in in xfile_loadChristoph Hellwig
Switch to using shmem_get_folio in xfile_load instead of using shmem_read_mapping_page_gfp. This gets us support for large folios and also optimized reading from unallocated space, as shmem_get_folio with SGP_READ won't allocate a page for them just to zero the content. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: use shmem_get_folio in xfile_obj_storeChristoph Hellwig
Switch to using shmem_get_folio and manually dirtying the page instead of abusing aops->write_begin and aops->write_end in xfile_get_page. This simplifies the code by not doing indirect calls of not actually exported interfaces that don't really fit the use case very well, and happens to get us large folio support for free. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: don't allow highmem pages in xfile mappingsChristoph Hellwig
XFS is generally used on 64-bit, non-highmem platforms and xfile mappings are accessed all the time. Reduce our pain by not allowing any highmem mappings in the xfile page cache and remove all the kmap calls for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: don't try to handle non-update pages in xfile_obj_loadChristoph Hellwig
shmem_read_mapping_page_gfp always returns an uptodate page or an ERR_PTR. Remove the code that tries to handle a non-uptodate page. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: remove the xfile_pread/pwrite APIsChristoph Hellwig
All current and pending xfile users use the xfile_obj_load and xfile_obj_store API, so make those the actual implementation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: remove xfile_statChristoph Hellwig
vfs_getattr is needed to query inode attributes for unknown underlying file systems. But shmemfs is well known for users of shmem_file_setup and shmem_read_mapping_page_gfp that rely on it not needing specific inode revalidation and having a normal mapping. Remove the detour through the getattr method and an extra wrapper, and just read the inode size and i_bytes directly in the scrub tracing code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: don't modify file and inode flags for shmem filesChristoph Hellwig
shmem_file_setup is explicitly intended for a file that can be fully read and written by kernel users without restrictions. Don't poke into internals to change random flags in the file or inode. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: use shmem_kernel_file_setup in xfile_createChristoph Hellwig
shmem_kernel_file_setup is equivalent to shmem_file_setup except that it already sets the S_PRIVATE flag. Use it instead of open coding the logic. 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: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: shmem_file_setup can't return NULLChristoph Hellwig
shmem_file_setup always returns a struct file pointer or an ERR_PTR, so remove the code to check for a NULL return. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-21xfs: use VM_NORESERVE in xfile_createChristoph Hellwig
xfile_create creates a (potentially large) sparse file. Pass VM_NORESERVE to shmem_file_setup to not account for the entire file size at file creation time. Reported-by: Hugh Dickins <hughd@google.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-20xfs: use kvfree in xfs_ioc_getfsmap()Dave Chinner
Another incorrect conversion to kfree() instead of kvfree(). Fixes: 49292576136f ("xfs: convert kmem_free() for kvmalloc users to kvfree()") Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-20xfs: use kvfree() in xfs_ioc_attr_list()Dave Chinner
Wrongly converted from kmem_free() to kfree(). Reported-by: Matthew Wilcox <willy@infradead.org> Fixes: 49292576136f ("xfs: convert kmem_free() for kvmalloc users to kvfree()") Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-19xfs: Remove mrlock wrapperMatthew Wilcox (Oracle)
mrlock was an rwsem wrapper that also recorded whether the lock was held for read or write. Now that we can ask the generic code whether the lock is held for read or write, we can remove this wrapper and use an rwsem directly. As the comment says, we can't use lockdep to assert that the ILOCK is held for write, because we might be in a workqueue, and we aren't able to tell lockdep that we do in fact own the lock. Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-19xfs: Replace xfs_isilocked with xfs_assert_ilockedMatthew Wilcox (Oracle)
To use the new rwsem_assert_held()/rwsem_assert_held_write(), we can't use the existing ASSERT macro. Add a new xfs_assert_ilocked() and convert all the callers. Fix an apparent bug in xfs_isilocked(): If the caller specifies XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL, xfs_assert_ilocked() will check both the IOLOCK and the ILOCK are held for write. xfs_isilocked() only checked that the ILOCK was held for write. xfs_assert_ilocked() is always on, even if DEBUG or XFS_WARN aren't defined. It's a cheap check, so I don't think it's worth defining it away. Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-19xfs: use kvfree for buf in xfs_ioc_getbmapChristoph Hellwig
Without this the kernel crashes in kfree for files with a sufficiently large number of extents. Fixes: d4c75a1b40cd ("xfs: convert remaining kmem_free() to kfree()") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-17xfs: ensure submit buffers on LSN boundaries in error handlersLong Li
While performing the IO fault injection test, I caught the following data corruption report: XFS (dm-0): Internal error ltbno + ltlen > bno at line 1957 of file fs/xfs/libxfs/xfs_alloc.c. Caller xfs_free_ag_extent+0x79c/0x1130 CPU: 3 PID: 33 Comm: kworker/3:0 Not tainted 6.5.0-rc7-next-20230825-00001-g7f8666926889 #214 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 Workqueue: xfs-inodegc/dm-0 xfs_inodegc_worker Call Trace: <TASK> dump_stack_lvl+0x50/0x70 xfs_corruption_error+0x134/0x150 xfs_free_ag_extent+0x7d3/0x1130 __xfs_free_extent+0x201/0x3c0 xfs_trans_free_extent+0x29b/0xa10 xfs_extent_free_finish_item+0x2a/0xb0 xfs_defer_finish_noroll+0x8d1/0x1b40 xfs_defer_finish+0x21/0x200 xfs_itruncate_extents_flags+0x1cb/0x650 xfs_free_eofblocks+0x18f/0x250 xfs_inactive+0x485/0x570 xfs_inodegc_worker+0x207/0x530 process_scheduled_works+0x24a/0xe10 worker_thread+0x5ac/0xc60 kthread+0x2cd/0x3c0 ret_from_fork+0x4a/0x80 ret_from_fork_asm+0x11/0x20 </TASK> XFS (dm-0): Corruption detected. Unmount and run xfs_repair After analyzing the disk image, it was found that the corruption was triggered by the fact that extent was recorded in both inode datafork and AGF btree blocks. After a long time of reproduction and analysis, we found that the reason of free sapce btree corruption was that the AGF btree was not recovered correctly. Consider the following situation, Checkpoint A and Checkpoint B are in the same record and share the same start LSN1, buf items of same object (AGF btree block) is included in both Checkpoint A and Checkpoint B. If the buf item in Checkpoint A has been recovered and updates metadata LSN permanently, then the buf item in Checkpoint B cannot be recovered, because log recovery skips items with a metadata LSN >= the current LSN of the recovery item. If there is still an inode item in Checkpoint B that records the Extent X, the Extent X will be recorded in both inode datafork and AGF btree block after Checkpoint B is recovered. Such transaction can be seen when allocing enxtent for inode bmap, it record both the addition of extent to the inode extent list and the removing extent from the AGF. |------------Record (LSN1)------------------|---Record (LSN2)---| |-------Checkpoint A----------|----------Checkpoint B-----------| | Buf Item(Extent X) | Buf Item / Inode item(Extent X) | | Extent X is freed | Extent X is allocated | After commit 12818d24db8a ("xfs: rework log recovery to submit buffers on LSN boundaries") was introduced, we submit buffers on lsn boundaries during log recovery. The above problem can be avoided under normal paths, but it's not guaranteed under abnormal paths. Consider the following process, if an error was encountered after recover buf item in Checkpoint A and before recover buf item in Checkpoint B, buffers that have been added to the buffer_list will still be submitted, this violates the submits rule on lsn boundaries. So buf item in Checkpoint B cannot be recovered on the next mount due to current lsn of transaction equal to metadata lsn on disk. The detailed process of the problem is as follows. First Mount: xlog_do_recovery_pass error = xlog_recover_process xlog_recover_process_data xlog_recover_process_ophdr xlog_recovery_process_trans ... /* recover buf item in Checkpoint A */ xlog_recover_buf_commit_pass2 xlog_recover_do_reg_buffer /* add buffer of agf btree block to buffer_list */ xfs_buf_delwri_queue(bp, buffer_list) ... ==> Encounter read IO error and return /* submit buffers regardless of error */ if (!list_empty(&buffer_list)) xfs_buf_delwri_submit(&buffer_list); <buf items of agf btree block in Checkpoint A recovery success> Second Mount: xlog_do_recovery_pass error = xlog_recover_process xlog_recover_process_data xlog_recover_process_ophdr xlog_recovery_process_trans ... /* recover buf item in Checkpoint B */ xlog_recover_buf_commit_pass2 /* buffer of agf btree block wouldn't added to buffer_list due to lsn equal to current_lsn */ if (XFS_LSN_CMP(lsn, current_lsn) >= 0) goto out_release <buf items of agf btree block in Checkpoint B wouldn't recovery> In order to make sure that submits buffers on lsn boundaries in the abnormal paths, we need to check error status before submit buffers that have been added from the last record processed. If error status exist, buffers in the bufffer_list should not be writen to disk. Canceling the buffers in the buffer_list directly isn't correct, unlike any other place where write list was canceled, these buffers has been initialized by xfs_buf_item_init() during recovery and held by buf item, buf items will not be released in xfs_buf_delwri_cancel(), it's not easy to solve. If the filesystem has been shut down, then delwri list submission will error out all buffers on the list via IO submission/completion and do all the correct cleanup automatically. So shutting down the filesystem could prevents buffers in the bufffer_list from being written to disk. Fixes: 50d5c8d8e938 ("xfs: check LSN ordering for v5 superblocks during recovery") Signed-off-by: Long Li <leo.lilong@huawei.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-17xfs: remove duplicate ifdefsShrikanth Hegde
when a ifdef is used in the below manner, second one could be considered as duplicate. ifdef DEFINE_A ...code block... ifdef DEFINE_A ...code block... endif ...code block... endif In the xfs code two such patterns were seen. Hence removing these ifdefs. No functional change is intended here. It only aims to improve code readability. Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-17xfs: disable sparse inode chunk alignment check when there is no alignmentDarrick J. Wong
While testing a 64k-blocksize filesystem, I noticed that xfs/709 fails to rebuild the inode btree with a bunch of "Corruption remains" messages. It turns out that when the inode chunk size is smaller than a single filesystem block, no block alignments constraints are necessary for inode chunk allocations, and sb_spino_align is zero. Hence we can skip the check. Fixes: dbfbf3bdf639 ("xfs: repair inode btrees") Signed-off-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>
2024-02-13xfs: use xfs_defer_alloc a bit moreDave Chinner
Noticed by inspection, simple factoring allows the same allocation routine to be used for both transaction and recovery contexts. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: clean up remaining GFP_NOFS usersDave Chinner
These few remaining GFP_NOFS callers do not need to use GFP_NOFS at all. They are only called from a non-transactional context or cannot be accessed from memory reclaim due to other constraints. Hence they can just use GFP_KERNEL. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: place the CIL under nofs allocation contextDave Chinner
This is core code that needs to run in low memory conditions and can be triggered from memory reclaim. While it runs in a workqueue, it really shouldn't be recursing back into the filesystem during any memory allocation it needs to function. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: place intent recovery under NOFS allocation contextDave Chinner
When recovery starts processing intents, all of the initial intent allocations are done outside of transaction contexts. That means they need to specifically use GFP_NOFS as we do not want memory reclaim to attempt to run direct reclaim of filesystem objects while we have lots of objects added into deferred operations. Rather than use GFP_NOFS for these specific allocations, just place the entire intent recovery process under NOFS context and we can then just use GFP_KERNEL for these allocations. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: use GFP_KERNEL in pure transaction contextsDave Chinner
When running in a transaction context, memory allocations are scoped to GFP_NOFS. Hence we don't need to use GFP_NOFS contexts in pure transaction context allocations - GFP_KERNEL will automatically get converted to GFP_NOFS as appropriate. Go through the code and convert all the obvious GFP_NOFS allocations in transaction context to use GFP_KERNEL. This further reduces the explicit use of GFP_NOFS in XFS. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: use __GFP_NOLOCKDEP instead of GFP_NOFSDave Chinner
In the past we've had problems with lockdep false positives stemming from inode locking occurring in memory reclaim contexts (e.g. from superblock shrinkers). Lockdep doesn't know that inodes access from above memory reclaim cannot be accessed from below memory reclaim (and vice versa) but there has never been a good solution to solving this problem with lockdep annotations. This situation isn't unique to inode locks - buffers are also locked above and below memory reclaim, and we have to maintain lock ordering for them - and against inodes - appropriately. IOWs, the same code paths and locks are taken both above and below memory reclaim and so we always need to make sure the lock orders are consistent. We are spared the lockdep problems this might cause by the fact that semaphores and bit locks aren't covered by lockdep. In general, this sort of lockdep false positive detection is cause by code that runs GFP_KERNEL memory allocation with an actively referenced inode locked. When it is run from a transaction, memory allocation is automatically GFP_NOFS, so we don't have reclaim recursion issues. So in the places where we do memory allocation with inodes locked outside of a transaction, we have explicitly set them to use GFP_NOFS allocations to prevent lockdep false positives from being reported if the allocation dips into direct memory reclaim. More recently, __GFP_NOLOCKDEP was added to the memory allocation flags to tell lockdep not to track that particular allocation for the purposes of reclaim recursion detection. This is a much better way of preventing false positives - it allows us to use GFP_KERNEL context outside of transactions, and allows direct memory reclaim to proceed normally without throwing out false positive deadlock warnings. The obvious places that lock inodes and do memory allocation are the lookup paths and inode extent list initialisation. These occur in non-transactional GFP_KERNEL contexts, and so can run direct reclaim and lock inodes. This patch makes a first path through all the explicit GFP_NOFS allocations in XFS and converts the obvious ones to GFP_KERNEL | __GFP_NOLOCKDEP as a first step towards removing explicit GFP_NOFS allocations from the XFS code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: use an empty transaction for fstrimDave Chinner
We currently use a btree walk in the fstrim code. This requires a btree cursor and btree cursors are only used inside transactions except for the fstrim code. This means that all the btree operations that allocate memory operate in both GFP_KERNEL and GFP_NOFS contexts. This causes problems with lockdep being unable to determine the difference between objects that are safe to lock both above and below memory reclaim. Free space btree buffers are definitely locked both above and below reclaim and that means we have to mark all btree infrastructure allocations with GFP_NOFS to avoid potential lockdep false positives. If we wrap this btree walk in an empty cursor, all btree walks are now done under transaction context and so all allocations inherit GFP_NOFS context from the tranaction. This enables us to move all the btree allocations to GFP_KERNEL context and hence help remove the explicit use of GFP_NOFS in XFS. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: convert remaining kmem_free() to kfree()Dave Chinner
The remaining callers of kmem_free() are freeing heap memory, so we can convert them directly to kfree() and get rid of kmem_free() altogether. This conversion was done with: $ for f in `git grep -l kmem_free fs/xfs`; do > sed -i s/kmem_free/kfree/ $f > done $ Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: convert kmem_free() for kvmalloc users to kvfree()Dave Chinner
Start getting rid of kmem_free() by converting all the cases where memory can come from vmalloc interfaces to calling kvfree() directly. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: move kmem_to_page()Dave Chinner
Move it to the general xfs linux wrapper header file so we can prepare to remove kmem.h Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: convert kmem_alloc() to kmalloc()Dave Chinner
kmem_alloc() is just a thin wrapper around kmalloc() these days. Convert everything to use kmalloc() so we can get rid of the wrapper. Note: the transaction region allocation in xlog_add_to_transaction() can be a high order allocation. Converting it to use kmalloc(__GFP_NOFAIL) results in warnings in the page allocation code being triggered because the mm subsystem does not want us to use __GFP_NOFAIL with high order allocations like we've been doing with the kmem_alloc() wrapper for a couple of decades. Hence this specific case gets converted to xlog_kvmalloc() rather than kmalloc() to avoid this issue. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: convert kmem_zalloc() to kzalloc()Dave Chinner
There's no reason to keep the kmem_zalloc() around anymore, it's just a thin wrapper around kmalloc(), so lets get rid of it. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-12xfs: add support for FS_IOC_GETFSSYSFSPATHKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev> Link: https://lore.kernel.org/r/20240207025624.1019754-7-kent.overstreet@linux.dev Signed-off-by: Christian Brauner <brauner@kernel.org>