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linux/fs/xfs/scrub/findparent.h

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xfs: scan the filesystem to repair a directory dotdot entry Teach the online directory repair code to scan the filesystem so that we can set the dotdot entry when we're rebuilding a directory. This involves dropping ILOCK on the directory that we're repairing, which means that the VFS can sneak in and tell us to update dotdot at any time. Deal with these races by using a dirent hook to absorb dotdot updates, and be careful not to check the scan results until after we've retaken the ILOCK. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15 21:54:52 +00:00
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (c) 2020-2024 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#ifndef __XFS_SCRUB_FINDPARENT_H__
#define __XFS_SCRUB_FINDPARENT_H__
struct xrep_parent_scan_info {
struct xfs_scrub *sc;
/* Inode scan cursor. */
struct xchk_iscan iscan;
/* Hook to capture directory entry updates. */
struct xfs_dir_hook dhook;
/* Lock protecting parent_ino. */
struct mutex lock;
/* Parent inode that we've found. */
xfs_ino_t parent_ino;
bool lookup_parent;
};
xfs: implement live updates for directory repairs While we're scanning the filesystem for parent pointers that we can turn into dirents, we cannot hold the IOLOCK or ILOCK of the directory being repaired. Therefore, we need to set up a dirent hook so that we can keep the temporary directory up to date with the rest of the filesystem. Hence we add the ability to *remove* entries from the temporary dir. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-22 16:48:10 +00:00
int __xrep_findparent_scan_start(struct xfs_scrub *sc,
struct xrep_parent_scan_info *pscan,
notifier_fn_t custom_fn);
static inline int xrep_findparent_scan_start(struct xfs_scrub *sc,
struct xrep_parent_scan_info *pscan)
{
return __xrep_findparent_scan_start(sc, pscan, NULL);
}
xfs: scan the filesystem to repair a directory dotdot entry Teach the online directory repair code to scan the filesystem so that we can set the dotdot entry when we're rebuilding a directory. This involves dropping ILOCK on the directory that we're repairing, which means that the VFS can sneak in and tell us to update dotdot at any time. Deal with these races by using a dirent hook to absorb dotdot updates, and be careful not to check the scan results until after we've retaken the ILOCK. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15 21:54:52 +00:00
int xrep_findparent_scan(struct xrep_parent_scan_info *pscan);
void xrep_findparent_scan_teardown(struct xrep_parent_scan_info *pscan);
static inline void
xrep_findparent_scan_found(
struct xrep_parent_scan_info *pscan,
xfs_ino_t ino)
{
mutex_lock(&pscan->lock);
pscan->parent_ino = ino;
mutex_unlock(&pscan->lock);
}
void xrep_findparent_scan_finish_early(struct xrep_parent_scan_info *pscan,
xfs_ino_t ino);
int xrep_findparent_confirm(struct xfs_scrub *sc, xfs_ino_t *parent_ino);
xfs_ino_t xrep_findparent_self_reference(struct xfs_scrub *sc);
xfs: ask the dentry cache if it knows the parent of a directory It's possible that the dentry cache can tell us the parent of a directory. Therefore, when repairing directory dot dot entries, query the dcache as a last resort before scanning the entire filesystem. A reviewer asks: "How high is the chance that we actually have a valid dcache entry for a file in a corrupted directory?" There's a decent chance of this actually working. Say you have a 1000-block directory foo, and block 980 gets corrupted. Let's further suppose that block 0 has a correct entry for ".." and "bar". If someone accesses /mnt/foo/bar, that will cause the dcache to create a dentry from /mnt to /mnt/foo whose d_parent points back to /mnt. If you then want to rebuild the directory, XFS can obtain the parent from the dcache without needing to wander into parent pointers or scan the filesystem to find /mnt's connection to foo. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15 21:54:54 +00:00
xfs_ino_t xrep_findparent_from_dcache(struct xfs_scrub *sc);
xfs: scan the filesystem to repair a directory dotdot entry Teach the online directory repair code to scan the filesystem so that we can set the dotdot entry when we're rebuilding a directory. This involves dropping ILOCK on the directory that we're repairing, which means that the VFS can sneak in and tell us to update dotdot at any time. Deal with these races by using a dirent hook to absorb dotdot updates, and be careful not to check the scan results until after we've retaken the ILOCK. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15 21:54:52 +00:00
#endif /* __XFS_SCRUB_FINDPARENT_H__ */
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