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path: root/fs/xfs/scrub/nlinks.c
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2024-04-23xfs: add a per-leaf block callback to xchk_xattr_walkDarrick J. Wong1-1/+2
Add a second callback function to xchk_xattr_walk so that we can do something in between attr leaf blocks. This will be used by the next patch to see if we should flush cached parent pointer updates to constrain memory usage. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-23xfs: walk directory parent pointers to determine backref countDarrick J. Wong1-1/+84
If the filesystem has parent pointers enabled, walk the parent pointers of subdirectories to determine the true backref count. In theory each subdir should have a single parent reachable via dotdot, but in the case of (corrupt) subdirs with multiple parents, we need to keep the link counts high enough that the directory loop detector will be able to correct the multiple parents problems. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15xfs: pin inodes that would otherwise overflow link countDarrick J. Wong1-1/+3
The VFS inc_nlink function does not explicitly check for integer overflows in the i_nlink field. Instead, it checks the link count against s_max_links in the vfs_{link,create,rename} functions. XFS sets the maximum link count to 2.1 billion, so integer overflows should not be a problem. However. It's possible that online repair could find that a file has more than four billion links, particularly if the link count got corrupted while creating hardlinks to the file. The di_nlinkv2 field is not large enough to store a value larger than 2^32, so we ought to define a magic pin value of ~0U which means that the inode never gets deleted. This will prevent a UAF error if the repair finds this situation and users begin deleting links to the file. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15xfs: move files to orphanage instead of letting nlinks drop to zeroDarrick J. Wong1-5/+15
If we encounter an inode with a nonzero link count but zero observed links, move it to the orphanage. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15xfs: online repair of directoriesDarrick J. Wong1-0/+23
If a directory looks like it's in bad shape, try to sift through the rubble to find whatever directory entries we can, scan the directory tree for the parent (if needed), stage the new directory contents in a temporary file and use the atomic extent swapping mechanism to commit the results in bulk. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: teach repair to fix file nlinksDarrick J. Wong1-1/+3
Fix the file link counts since we just computed the correct ones. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: track directory entry updates during live nlinks fsckDarrick J. Wong1-2/+91
Create the necessary hooks in the directory operations (create/link/unlink/rename) code so that our live nlink scrub code can stay up to date with link count updates in the rest of the filesystem. This will be the means to keep our shadow link count information up to date while the scan runs in real time. In online fsck part 2, we'll use these same hooks to handle repairs to directories and parent pointer information. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: teach scrub to check file nlinksDarrick J. Wong1-0/+839
Create the necessary scrub code to walk the filesystem's directory tree so that we can compute file link counts. Similar to quotacheck, we create an incore shadow array of link count information and then we walk the filesystem a second time to compare the link counts. We need live updates to keep the information up to date during the lengthy scan, so this scrubber remains disabled until the next patch. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>