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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>
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (c) 2021-2024 Oracle. All Rights Reserved.
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* Author: Darrick J. Wong <djwong@kernel.org>
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*/
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#ifndef __XFS_SCRUB_NLINKS_H__
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#define __XFS_SCRUB_NLINKS_H__
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/* Live link count control structure. */
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struct xchk_nlink_ctrs {
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struct xfs_scrub *sc;
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/* Shadow link count data and its mutex. */
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struct xfarray *nlinks;
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struct mutex lock;
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/*
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* The collection step uses a separate iscan context from the compare
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* step because the collection iscan coordinates live updates to the
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* observation data while this scanner is running. The compare iscan
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* is secondary and can be reinitialized as needed.
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*/
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struct xchk_iscan collect_iscan;
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struct xchk_iscan compare_iscan;
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/*
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* Hook into directory updates so that we can receive live updates
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* from other writer threads.
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*/
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struct xfs_dir_hook dhook;
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/* Orphanage reparenting request. */
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struct xrep_adoption adoption;
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/* Directory entry name, plus the trailing null. */
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struct xfs_name xname;
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char namebuf[MAXNAMELEN];
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};
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/*
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* In-core link counts for a given inode in the filesystem.
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*
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* For an empty rootdir, the directory entries and the field to which they are
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* accounted are as follows:
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*
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* Root directory:
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*
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* . points to self (root.child)
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* .. points to self (root.parent)
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* f1 points to a child file (f1.parent)
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* d1 points to a child dir (d1.parent, root.child)
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*
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* Subdirectory d1:
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*
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* . points to self (d1.child)
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* .. points to root dir (root.backref)
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* f2 points to child file (f2.parent)
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* f3 points to root.f1 (f1.parent)
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*
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* root.nlink == 3 (root.dot, root.dotdot, root.d1)
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* d1.nlink == 2 (root.d1, d1.dot)
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* f1.nlink == 2 (root.f1, d1.f3)
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* f2.nlink == 1 (d1.f2)
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*/
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struct xchk_nlink {
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/* Count of forward links from parent directories to this file. */
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xfs_nlink_t parents;
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/*
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* Count of back links to this parent directory from child
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* subdirectories.
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*/
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xfs_nlink_t backrefs;
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/*
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* Count of forward links from this directory to all child files and
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* the number of dot entries. Should be zero for non-directories.
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*/
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xfs_nlink_t children;
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/* Record state flags */
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unsigned int flags;
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};
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/*
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* This incore link count has been written at least once. We never want to
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* store an xchk_nlink that looks uninitialized.
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*/
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#define XCHK_NLINK_WRITTEN (1U << 0)
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/* Already checked this link count record. */
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#define XCHK_NLINK_COMPARE_SCANNED (1U << 1)
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/* Already made a repair with this link count record. */
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#define XREP_NLINK_DIRTY (1U << 2)
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/* Compute total link count, using large enough variables to detect overflow. */
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static inline uint64_t
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xchk_nlink_total(struct xfs_inode *ip, const struct xchk_nlink *live)
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{
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uint64_t ret = live->parents;
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/* Add one link count for the dot entry of any linked directory. */
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if (ip && S_ISDIR(VFS_I(ip)->i_mode) && VFS_I(ip)->i_nlink)
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ret++;
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return ret + live->children;
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}
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#endif /* __XFS_SCRUB_NLINKS_H__ */
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