From 6d03a247468059b0e59c821ef39e6762d4d6fc30 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 19 Jun 2024 23:00:51 +0200 Subject: Merging upstream version 6.9.2. Signed-off-by: Daniel Baumann --- fs/xfs/scrub/nlinks.h | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 fs/xfs/scrub/nlinks.h (limited to 'fs/xfs/scrub/nlinks.h') diff --git a/fs/xfs/scrub/nlinks.h b/fs/xfs/scrub/nlinks.h new file mode 100644 index 0000000000..a950f3daf2 --- /dev/null +++ b/fs/xfs/scrub/nlinks.h @@ -0,0 +1,102 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (c) 2021-2024 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#ifndef __XFS_SCRUB_NLINKS_H__ +#define __XFS_SCRUB_NLINKS_H__ + +/* Live link count control structure. */ +struct xchk_nlink_ctrs { + struct xfs_scrub *sc; + + /* Shadow link count data and its mutex. */ + struct xfarray *nlinks; + struct mutex lock; + + /* + * The collection step uses a separate iscan context from the compare + * step because the collection iscan coordinates live updates to the + * observation data while this scanner is running. The compare iscan + * is secondary and can be reinitialized as needed. + */ + struct xchk_iscan collect_iscan; + struct xchk_iscan compare_iscan; + + /* + * Hook into directory updates so that we can receive live updates + * from other writer threads. + */ + struct xfs_dir_hook dhook; +}; + +/* + * In-core link counts for a given inode in the filesystem. + * + * For an empty rootdir, the directory entries and the field to which they are + * accounted are as follows: + * + * Root directory: + * + * . points to self (root.child) + * .. points to self (root.parent) + * f1 points to a child file (f1.parent) + * d1 points to a child dir (d1.parent, root.child) + * + * Subdirectory d1: + * + * . points to self (d1.child) + * .. points to root dir (root.backref) + * f2 points to child file (f2.parent) + * f3 points to root.f1 (f1.parent) + * + * root.nlink == 3 (root.dot, root.dotdot, root.d1) + * d1.nlink == 2 (root.d1, d1.dot) + * f1.nlink == 2 (root.f1, d1.f3) + * f2.nlink == 1 (d1.f2) + */ +struct xchk_nlink { + /* Count of forward links from parent directories to this file. */ + xfs_nlink_t parents; + + /* + * Count of back links to this parent directory from child + * subdirectories. + */ + xfs_nlink_t backrefs; + + /* + * Count of forward links from this directory to all child files and + * the number of dot entries. Should be zero for non-directories. + */ + xfs_nlink_t children; + + /* Record state flags */ + unsigned int flags; +}; + +/* + * This incore link count has been written at least once. We never want to + * store an xchk_nlink that looks uninitialized. + */ +#define XCHK_NLINK_WRITTEN (1U << 0) + +/* Already checked this link count record. */ +#define XCHK_NLINK_COMPARE_SCANNED (1U << 1) + +/* Already made a repair with this link count record. */ +#define XREP_NLINK_DIRTY (1U << 2) + +/* Compute total link count, using large enough variables to detect overflow. */ +static inline uint64_t +xchk_nlink_total(struct xfs_inode *ip, const struct xchk_nlink *live) +{ + uint64_t ret = live->parents; + + /* Add one link count for the dot entry of any linked directory. */ + if (ip && S_ISDIR(VFS_I(ip)->i_mode) && VFS_I(ip)->i_nlink) + ret++; + return ret + live->children; +} + +#endif /* __XFS_SCRUB_NLINKS_H__ */ -- cgit v1.2.3