- 24 Feb, 2024 13 commits
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Chandan Babu R authored
Merge tag 'repair-rmap-btree-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: online repair of rmap btrees We have now constructed the four tools that we need to scan the filesystem looking for reverse mappings: an inode scanner, hooks to receive live updates from other writer threads, the ability to construct btrees in memory, and a btree bulk loader. This series glues those three together, enabling us to scan the filesystem for mappings and keep it up to date while other writers run, and then commit the new btree to disk atomically. To reduce the size of each patch, the functionality is left disabled until the end of the series and broken up into three patches: one to create the mechanics of scanning the filesystem, a second to transition to in-memory btrees, and a third to set up the live hooks. Signed-off-by:
Darrick J. Wong <djwong@kernel.org> Signed-off-by:
Chandan Babu R <chandanbabu@kernel.org> * tag 'repair-rmap-btree-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux: xfs: hook live rmap operations during a repair operation xfs: create a shadow rmap btree during rmap repair xfs: repair the rmapbt xfs: create agblock bitmap helper to count the number of set regions xfs: create a helper to decide if a file mapping targets the rt volume
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Chandan Babu R authored
Merge tag 'in-memory-btrees-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: support in-memory btrees Online repair of the reverse-mapping btrees presens some unique challenges. To construct a new reverse mapping btree, we must scan the entire filesystem, but we cannot afford to quiesce the entire filesystem for the potentially lengthy scan. For rmap btrees, therefore, we relax our requirements of totally atomic repairs. Instead, repairs will scan all inodes, construct a new reverse mapping dataset, format a new btree, and commit it before anyone trips over the corruption. This is exactly the same strategy as was used in the quotacheck and nlink scanners. Unfortunately, the xfarray cannot perform key-based lookups and is therefore unsuitable for supporting live updates. Luckily, we already a data structure that maintains an indexed rmap recordset -- the existing rmap btree code! Hence we port the existing btree and buffer target code to be able to create a btree using the xfile we developed earlier. Live hooks keep the in-memory btree up to date for any resources that have already been scanned. This approach is not maximally memory efficient, but we can use the same rmap code that we do everywhere else, which provides improved stability without growing the code base even more. Note that in-memory btree blocks are always page sized. This patchset modifies the kernel xfs buffer cache to be capable of using a xfile (aka a shmem file) as a backing device. It then augments the btree code to support creating btree cursors with buffers that come from a buftarg other than the data device (namely an xfile-backed buftarg). For the userspace xfs buffer cache, we instead use a memfd or an O_TMPFILE file as a backing device. Signed-off-by:
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Chandan Babu R authored
Merge tag 'buftarg-cleanups-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: buftarg cleanups Clean up the buffer target code in preparation for adding the ability to target tmpfs files. That will enable the creation of in memory btrees. Signed-off-by:
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Chandan Babu R authored
Merge tag 'btree-readahead-cleanups-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: btree readahead cleanups Minor cleanups for the btree block readahead code. Signed-off-by:
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Chandan Babu R authored
Merge tag 'btree-check-cleanups-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: btree check cleanups Minor cleanups for the btree block pointer checking code. Signed-off-by:
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Chandan Babu R authored
Merge tag 'btree-remove-btnum-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: remove bc_btnum from btree cursors From Christoph Hellwig, This series continues the migration of btree geometry information out of the cursor structure and into the ops structure. This time around, we replace the btree type enumeration (btnum) with an explicit name string in the btree ops structure. This enables easy creation of /any/ new btree type without having to mess with libxfs. Signed-off-by:
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Chandan Babu R authored
Merge tag 'btree-geometry-in-ops-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: move btree geometry to ops struct This patchset prepares the generic btree code to allow for the creation of new btree types outside of libxfs. The end goal here is for online fsck to be able to create its own in-memory btrees that will be used to improve the performance (and reduce the memory requirements of) the refcount btree. To enable this, I decided that the btree ops structure is the ideal place to encode all of the geometry information about a btree. The btree ops struture already contains the buffer ops (and hence the btree block magic numbers) as well as the key and record sizes, so it doesn't seem all that farfetched to encode the XFS_BTREE_ flags that determine the geometry (ROOT_IN_INODE, LONG_PTRS, etc). The rest of the patchset cleans up the btree functions that initialize btree blocks and btree buffers. The bulk of this work is to replace btree geometry related function call arguments with a single pointer to the ops structure, and then clean up everything else around that. As a side effect, we rename the functions. Later, Christoph Hellwig and I merged together a bunch more cleanups that he wanted to do for a while. All the btree geometry information is now in the btree ops structure, we've created an explicit btree type (ag, inode, mem) and moved the per-btree type information to a separate union. Signed-off-by:
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Chandan Babu R authored
Merge tag 'repair-fscounters-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: online repair for fs summary counters A longstanding deficiency in the online fs summary counter scrubbing code is that it hasn't any means to quiesce the incore percpu counters while it's running. There is no way to coordinate with other threads are reserving or freeing free space simultaneously, which leads to false error reports. Right now, if the discrepancy is large, we just sort of shrug and bail out with an incomplete flag, but this is lame. For repair activity, we actually /do/ need to stabilize the counters to get an accurate reading and install it in the percpu counter. To improve the former and enable the latter, allow the fscounters online fsck code to perform an exclusive mini-freeze on the filesystem. The exclusivity prevents userspace from thawing while we're running, and the mini-freeze means that we don't wait for the log to quiesce, which will make both speedier. Signed-off-by:
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Chandan Babu R authored
Merge tag 'indirect-health-reporting-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: indirect health reporting This series enables the XFS health reporting infrastructure to remember indirect health concerns when resources are scarce. For example, if a scrub notices that there's something wrong with an inode's metadata but memory reclaim needs to free the incore inode, we want to record in the perag data the fact that there was some inode somewhere with an error. The perag structures never go away. The first two patches in this series set that up, and the third one provides a means for xfs_scrub to tell the kernel that it can forget the indirect problem report. Signed-off-by:
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Chandan Babu R authored
Merge tag 'corruption-health-reports-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: report corruption to the health trackers Any time that the runtime code thinks it has found corrupt metadata, it should tell the health tracking subsystem that the corresponding part of the filesystem is sick. These reports come primarily from two places -- code that is reading a buffer that fails validation, and higher level pieces that observe a conflict involving multiple buffers. This patchset uses automated scanning to update all such callsites with a mark_sick call. Doing this enables the health system to record problem observed at runtime, which (for now) can prompt the sysadmin to run xfs_scrub, and (later) may enable more targetted fixing of the filesystem. Note: Earlier reviewers of this patchset suggested that the verifier functions themselves should be responsible for calling _mark_sick. In a higher level language this would be easily accomplished with lambda functions and closures. For the kernel, however, we'd have to create the necessary closures by hand, pass them to the buf_read calls, and then implement necessary state tracking to detach the xfs_buf from the closure at the necessary time. This is far too much work and complexity and will not be pursued further. Signed-off-by:
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Chandan Babu R authored
Merge tag 'scrub-nlinks-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: online repair of file link counts Now that we've created the infrastructure to perform live scans of every file in the filesystem and the necessary hook infrastructure to observe live updates, use it to scan directories to compute the correct link counts for files in the filesystem, and reset those link counts. This patchset creates a tailored readdir implementation for scrub because the regular version has to cycle ILOCKs to copy information to userspace. We can't cycle the ILOCK during the nlink scan and we don't need all the other VFS support code (maintaining a readdir cursor and translating XFS structures to VFS structures and back) so it was easier to duplicate the code. Signed-off-by:
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Chandan Babu R authored
Merge tag 'repair-quotacheck-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: online repair of quota counters This series uses the inode scanner and live update hook functionality introduced in the last patchset to implement quotacheck on a live filesystem. The quotacheck scrubber builds an incore copy of the dquot resource usage counters and compares it to the live dquots to report discrepancies. If the user chooses to repair the quota counters, the repair function visits each incore dquot to update the counts from the live information. The live update hooks are key to keeping the incore copy up to date. Signed-off-by:
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Chandan Babu R authored
Merge tag 'repair-inode-mode-6.9_2024-02-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.9-mergeC xfs: repair inode mode by scanning dirs One missing piece of functionality in the inode record repair code is figuring out what to do with a file whose mode is so corrupt that we cannot tell us the type of the file. Originally this was done by guessing the mode from the ondisk inode contents, but Christoph didn't like that because it read from data fork block 0, which could be user controlled data. Therefore, I've replaced all that with a directory scanner that looks for any dirents that point to the file with the garbage mode. If so, the ftype in the dirent will tell us exactly what mode to set on the file. Since users cannot directly write to the ftype field of a dirent, this should be safe. Signed-off-by:
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- 22 Feb, 2024 27 commits
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Darrick J. Wong authored
Hook the regular rmap code when an rmapbt repair operation is running so that we can unlock the AGF buffer to scan the filesystem and keep the in-memory btree up to date during the scan. Signed-off-by:
Christoph Hellwig <hch@lst.de>
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Darrick J. Wong authored
Create an in-memory btree of rmap records instead of an array. This enables us to do live record collection instead of freezing the fs. Signed-off-by:
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Darrick J. Wong authored
Rebuild the reverse mapping btree from all primary metadata. This first patch establishes the bare mechanics of finding records and putting together a new ondisk tree; more complex pieces are needed to make it work properly. Link: Documentation/filesystems/xfs-online-fsck-design.rst Signed-off-by:
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Darrick J. Wong authored
In the next patch, the rmap btree repair code will need to estimate the size of the new ondisk rmapbt. The size is a function of the number of records that will be written to disk, and the size of the recordset is the number of observations made while scanning the filesystem plus the number of OWN_AG records that will be injected into the rmap btree. OWN_AG rmap records track the free space btrees, the AGFL, and the new rmap btree itself. The repair tool uses a bitmap to record the space used for all four structures, which is why we need a function to count the number of set regions. A reviewer requested that this be pulled into a separate patch with its own justification, so here it is. Signed-off-by:
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Darrick J. Wong authored
As we've noted in various places, all current users of in-memory btrees are online fsck. Online fsck only stages a btree long enough to rebuild an ondisk data structure, which means that the in-memory btree is ephemeral. Furthermore, if we encounter /any/ errors while updating an in-memory btree, all we do is tear down all the staged data and return an errno to userspace. In-memory btrees need not be transactional, so their buffers should not be committed to the ondisk log, nor should they be checkpointed by the AIL. That's just as well since the ephemeral nature of the btree means that the buftarg and the buffers may disappear quickly anyway. Therefore, we need a way to launder the btree buffers that get attached to the transaction by the generic btree code. Because the buffers are directly mapped to backing file pages, there's no need to bwrite them back to the tmpfs file. All we need to do is clean enough of the buffer log item state so that the bli can be detached from the buffer, remove the bli from the transaction's log item list, and reset the transaction dirty state as if the laundered items had never been there. For simplicity, create xfbtree transaction commit and cancel helpers that launder the in-memory btree buffers for callers. Once laundered, call the write verifier on non-stale buffers to avoid integrity issues, or punch a hole in the backing file for stale buffers. Signed-off-by:
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Darrick J. Wong authored
Create a helper so that we can stop open-coding this decision everywhere. Signed-off-by:
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Darrick J. Wong authored
Adapt the generic btree cursor code to be able to create a btree whose buffers come from a (presumably in-memory) buftarg with a header block that's specific to in-memory btrees. We'll connect this to other parts of online scrub in the next patches. Note that in-memory btrees always have a block size matching the system memory page size for efficiency reasons. There are also a few things we need to do to finalize a btree update; that's covered in the next patch. Signed-off-by:
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Christoph Hellwig authored
This only has a single caller and thus might be a bit questionable, but I think it really improves the readability of xfs_btree_visit_block. Signed-off-by:
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Darrick J. Wong authored
Allow the buffer cache to target in-memory files by making it possible to have a buftarg that maps pages from private shmem files. As the prevous patch alludes, the in-memory buftarg contains its own cache, points to a shmem file, and does not point to a block_device. The next few patches will make it possible to construct an xfs_btree in pageable memory by using this buftarg. Signed-off-by:
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Darrick J. Wong authored
Currently, cached buffers are indexed by per-AG hashtables. This works great for the data device, but won't work for in-memory btrees. To handle that use case, buftargs will need to be able to index buffers independently of other data structures. We accomplish this by hoisting the rhashtable and its lock into a separate xfs_buf_cache structure, make the buftarg point to the _buf_cache structure, and rework various functions to use it. This will enable the in-memory buftarg to come up with its own _buf_cache. Signed-off-by:
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Christoph Hellwig authored
bt_logical_sectorsize and the associated mask is set based on the constant logical block size in the block_device structure and thus doesn't need to be updated in xfs_setsize_buftarg. Move it into xfs_alloc_buftarg so that it is only done once per buftarg. Signed-off-by:
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Christoph Hellwig authored
Open code the logic in the only caller, and improve the comment explaining what is being done here. Signed-off-by:
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Christoph Hellwig authored
Switch the few remaining holdouts to the struct version. Signed-off-by:
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Christoph Hellwig authored
xfs_buf_rele is a bit confusing because it mixes up handling of normal cached and the special uncached buffers without much explanation. Split the handling into two different helpers, and use a clearly named helper that checks the hash key to distinguish the two cases instead of checking the pag pointer. Signed-off-by:
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Christoph Hellwig authored
Despite its name, xfs_btree_read_bufl doesn't contain any btree-related functionaliy and isn't used by the btree code. Move it to xfs_bmap.c, hard code the refval and ops arguments and rename it to xfs_bmap_read_buf. Signed-off-by:
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Christoph Hellwig authored
xfs_btree_reada_bufl just wraps xfs_btree_readahead and a agblock to daddr conversion. Just open code it's three callsites in the two callers (One of which isn't even btree related). Signed-off-by:
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Christoph Hellwig authored
xfs_btree_reada_bufl just wraps xfs_btree_readahead and a fsblock to daddr conversion. Just open code it's two callsites in the only caller. Signed-off-by:
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Christoph Hellwig authored
This will allow sharing code with the in-memory block checking helper. Signed-off-by:
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Christoph Hellwig authored
All these helpers hardcode fsblocks or agblocks and not just the pointer size. Rename them so that the names are still fitting when we add the long format in-memory blocks and adjust the checks when calling them to check the btree types and not just pointer length. Signed-off-by:
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Christoph Hellwig authored
Add a __xfs_btree_check_block helper that can be called by the scrub code to validate a btree block of any form, and move the duplicate error handling code from xfs_btree_check_sblock and xfs_btree_check_lblock into xfs_btree_check_block and thus remove these two helpers. Signed-off-by:
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Christoph Hellwig authored
Check that root blocks that sit in the inode fork and thus have a NULL bp don't have siblings. Signed-off-by:
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Christoph Hellwig authored
crc is only used once, just use the xfs_has_crc check directly. Signed-off-by:
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Christoph Hellwig authored
Remove the local crc variable that is only used once and remove the bp NULL checking as it can't ever be NULL for short form blocks. Signed-off-by:
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Christoph Hellwig authored
Merge xfs_btree_check_sptr and xfs_btree_check_lptr into a single __xfs_btree_check_ptr that can be shared between xfs_btree_check_ptr and the scrub code. Signed-off-by:
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Christoph Hellwig authored
xfs_bmap_btree_to_extents always passes a level of 1 to xfs_btree_check_lptr, thus making the level check redundant. Signed-off-by:
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Christoph Hellwig authored
Stop using xfs_btree_check_lptr in xfs_btree_check_lblock_siblings, as it only duplicates the xfs_verify_fsbno call in the other leg of if / else besides adding a tautological level check. With this the cur and level arguments can be removed as they are now unused. Signed-off-by:
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Christoph Hellwig authored
Stop using xfs_btree_check_sptr in xfs_btree_check_sblock_siblings, as it only duplicates the xfs_verify_agbno call in the other leg of if / else besides adding a tautological level check. With this the cur and level arguments can be removed as they are now unused. Signed-off-by:
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