[PATCH 15/26] xfs: refactor directory tree root predicates

Darrick J. Wong
2024-08-23T00:06:04Z

From: Darrick J. Wong <djwong@kernel.org>

Metadata directory trees make reasoning about the parent of a file more
difficult. Traditionally, user files are children of sb_rootino, and
metadata files are "children" of the superblock. Now, we add a third
possibility -- some metadata files can be children of sb_metadirino, but
the classic ones (rt free space data and quotas) are left alone.

Let's add some helper functions (instead of open-coding the logic
everywhere) to make scrub logic easier to understand.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/scrub/common.c | 29 +++++++++++++++++++++++++++++
fs/xfs/scrub/common.h | 4 ++++
fs/xfs/scrub/dir.c | 2 +-
fs/xfs/scrub/dir_repair.c | 2 +-
fs/xfs/scrub/dirtree.c | 15 ++++++++++++++-
fs/xfs/scrub/dirtree.h | 12 +-----------
fs/xfs/scrub/findparent.c | 15 +++++++++------
fs/xfs/scrub/inode_repair.c | 11 ++---------
fs/xfs/scrub/nlinks.c | 4 ++--
fs/xfs/scrub/nlinks_repair.c | 4 +---
fs/xfs/scrub/orphanage.c | 4 +++-
fs/xfs/scrub/parent.c | 17 ++++++++---------
fs/xfs/scrub/parent_repair.c | 2 +-
13 files changed, 76 insertions(+), 45 deletions(-)

diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index f64271ccb786c..72cec56f52eb1 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -1452,3 +1452,32 @@ xchk_inode_is_allocated(
rcu_read_unlock();
return error;
}
+
+/* Is this inode a root directory for either tree? */
+bool
+xchk_inode_is_dirtree_root(const struct xfs_inode *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+
+ return ip == mp->m_rootip ||
+ (xfs_has_metadir(mp) && ip == mp->m_metadirip);
+}
+
+/* Does the superblock point down to this inode? */
+bool
+xchk_inode_is_sb_rooted(const struct xfs_inode *ip)
+{
+ return xchk_inode_is_dirtree_root(ip) ||
+ xfs_internal_inum(ip->i_mount, ip->i_ino);
+}
+
+/* What is the root directory inumber for this inode? */
+xfs_ino_t
+xchk_inode_rootdir_inum(const struct xfs_inode *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+
+ if (xfs_is_metadir_inode(ip))
+ return mp->m_metadirip->i_ino;
+ return mp->m_rootip->i_ino;
+}
diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h
index 3d5f1f6b4b7bf..4d713e2a463cd 100644
--- a/fs/xfs/scrub/common.h
+++ b/fs/xfs/scrub/common.h
@@ -252,4 +252,8 @@ void xchk_fsgates_enable(struct xfs_scrub *sc, unsigned int scrub_fshooks);
int xchk_inode_is_allocated(struct xfs_scrub *sc, xfs_agino_t agino,
bool *inuse);

+bool xchk_inode_is_dirtree_root(const struct xfs_inode *ip);
+bool xchk_inode_is_sb_rooted(const struct xfs_inode *ip);
+xfs_ino_t xchk_inode_rootdir_inum(const struct xfs_inode *ip);
+
#endif /* __XFS_SCRUB_COMMON_H__ */
diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
index bf9199e8df633..6b719c8885ef7 100644
--- a/fs/xfs/scrub/dir.c
+++ b/fs/xfs/scrub/dir.c
@@ -253,7 +253,7 @@ xchk_dir_actor(
* If this is ".." in the root inode, check that the inum
* matches this dir.
*/
- if (dp->i_ino == mp->m_sb.sb_rootino && ino != dp->i_ino)
+ if (xchk_inode_is_dirtree_root(dp) && ino != dp->i_ino)
xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
}

diff --git a/fs/xfs/scrub/dir_repair.c b/fs/xfs/scrub/dir_repair.c
index 64679fe084465..0c2cd42b3110f 100644
--- a/fs/xfs/scrub/dir_repair.c
+++ b/fs/xfs/scrub/dir_repair.c
@@ -1270,7 +1270,7 @@ xrep_dir_scan_dirtree(
int error;

/* Roots of directory trees are their own parents. */
- if (sc->ip == sc->mp->m_rootip)
+ if (xchk_inode_is_dirtree_root(sc->ip))
xrep_findparent_scan_found(&rd->pscan, sc->ip->i_ino);

/*
diff --git a/fs/xfs/scrub/dirtree.c b/fs/xfs/scrub/dirtree.c
index bde58fb561ea1..e43840733de94 100644
--- a/fs/xfs/scrub/dirtree.c
+++ b/fs/xfs/scrub/dirtree.c
@@ -917,7 +917,7 @@ xchk_dirtree(
* scan, because the hook doesn't detach until after sc->ip gets
* released during teardown.
*/
- dl->root_ino = sc->mp->m_rootip->i_ino;
+ dl->root_ino = xchk_inode_rootdir_inum(sc->ip);
dl->scan_ino = sc->ip->i_ino;

trace_xchk_dirtree_start(sc->ip, sc->sm, 0);
@@ -983,3 +983,16 @@ xchk_dirtree(
trace_xchk_dirtree_done(sc->ip, sc->sm, error);
return error;
}
+
+/* Does the directory targetted by this scrub have no parents? */
+bool
+xchk_dirtree_parentless(const struct xchk_dirtree *dl)
+{
+ struct xfs_scrub *sc = dl->sc;
+
+ if (xchk_inode_is_dirtree_root(sc->ip))
+ return true;
+ if (VFS_I(sc->ip)->i_nlink == 0)
+ return true;
+ return false;
+}
diff --git a/fs/xfs/scrub/dirtree.h b/fs/xfs/scrub/dirtree.h
index 1e1686365c61c..9e5d95492717d 100644
--- a/fs/xfs/scrub/dirtree.h
+++ b/fs/xfs/scrub/dirtree.h
@@ -156,17 +156,7 @@ struct xchk_dirtree {
#define xchk_dirtree_for_each_path(dl, path) \
list_for_each_entry((path), &(dl)->path_list, list)

-static inline bool
-xchk_dirtree_parentless(const struct xchk_dirtree *dl)
-{
- struct xfs_scrub *sc = dl->sc;
-
- if (sc->ip == sc->mp->m_rootip)
- return true;
- if (VFS_I(sc->ip)->i_nlink == 0)
- return true;
- return false;
-}
+bool xchk_dirtree_parentless(const struct xchk_dirtree *dl);

int xchk_dirtree_find_paths_to_root(struct xchk_dirtree *dl);
int xchk_dirpath_append(struct xchk_dirtree *dl, struct xfs_inode *ip,
diff --git a/fs/xfs/scrub/findparent.c b/fs/xfs/scrub/findparent.c
index 01766041ba2cd..153d185190d8a 100644
--- a/fs/xfs/scrub/findparent.c
+++ b/fs/xfs/scrub/findparent.c
@@ -362,15 +362,18 @@ xrep_findparent_confirm(
};
int error;

- /*
- * The root directory always points to itself. Unlinked dirs can point
- * anywhere, so we point them at the root dir too.
- */
- if (sc->ip == sc->mp->m_rootip || VFS_I(sc->ip)->i_nlink == 0) {
+ /* The root directory always points to itself. */
+ if (sc->ip == sc->mp->m_rootip) {
*parent_ino = sc->mp->m_sb.sb_rootino;
return 0;
}

+ /* Unlinked dirs can point anywhere; point them up to the root dir. */
+ if (VFS_I(sc->ip)->i_nlink == 0) {
+ *parent_ino = xchk_inode_rootdir_inum(sc->ip);
+ return 0;
+ }
+
/* Reject garbage parent inode numbers and self-referential parents. */
if (*parent_ino == NULLFSINO)
return 0;
@@ -413,7 +416,7 @@ xrep_findparent_self_reference(
return sc->mp->m_sb.sb_rootino;

if (VFS_I(sc->ip)->i_nlink == 0)
- return sc->mp->m_sb.sb_rootino;
+ return xchk_inode_rootdir_inum(sc->ip);

return NULLFSINO;
}
diff --git a/fs/xfs/scrub/inode_repair.c b/fs/xfs/scrub/inode_repair.c
index 060ebfb25c7a5..91d0da58443a1 100644
--- a/fs/xfs/scrub/inode_repair.c
+++ b/fs/xfs/scrub/inode_repair.c
@@ -1768,15 +1768,8 @@ xrep_inode_pptr(
if (inode->i_nlink == 0 && !(inode->i_state & I_LINKABLE))
return 0;

- /* The root directory doesn't have a parent pointer. */
- if (ip == mp->m_rootip)
- return 0;
-
- /*
- * Metadata inodes are rooted in the superblock and do not have any
- * parents.
- */
- if (xfs_is_metadata_inode(ip))
+ /* Children of the superblock do not have parent pointers. */
+ if (xchk_inode_is_sb_rooted(ip))
return 0;

/* Inode already has an attr fork; no further work possible here. */
diff --git a/fs/xfs/scrub/nlinks.c b/fs/xfs/scrub/nlinks.c
index 80aee30886c45..4a47d0aabf73b 100644
--- a/fs/xfs/scrub/nlinks.c
+++ b/fs/xfs/scrub/nlinks.c
@@ -279,7 +279,7 @@ xchk_nlinks_collect_dirent(
* determine the backref count.
*/
if (dotdot) {
- if (dp == sc->mp->m_rootip)
+ if (xchk_inode_is_dirtree_root(dp))
error = xchk_nlinks_update_incore(xnc, ino, 1, 0, 0);
else if (!xfs_has_parent(sc->mp))
error = xchk_nlinks_update_incore(xnc, ino, 0, 1, 0);
@@ -735,7 +735,7 @@ xchk_nlinks_compare_inode(
}
}

- if (ip == sc->mp->m_rootip) {
+ if (xchk_inode_is_dirtree_root(ip)) {
/*
* For the root of a directory tree, both the '.' and '..'
* entries should point to the root directory. The dotdot
diff --git a/fs/xfs/scrub/nlinks_repair.c b/fs/xfs/scrub/nlinks_repair.c
index b3e707f47b7b5..4ebdee0954280 100644
--- a/fs/xfs/scrub/nlinks_repair.c
+++ b/fs/xfs/scrub/nlinks_repair.c
@@ -60,11 +60,9 @@ xrep_nlinks_is_orphaned(
unsigned int actual_nlink,
const struct xchk_nlink *obs)
{
- struct xfs_mount *mp = ip->i_mount;
-
if (obs->parents != 0)
return false;
- if (ip == mp->m_rootip || ip == sc->orphanage)
+ if (xchk_inode_is_dirtree_root(ip) || ip == sc->orphanage)
return false;
return actual_nlink != 0;
}
diff --git a/fs/xfs/scrub/orphanage.c b/fs/xfs/scrub/orphanage.c
index 7148d8362db83..11d7b8a62ebe1 100644
--- a/fs/xfs/scrub/orphanage.c
+++ b/fs/xfs/scrub/orphanage.c
@@ -295,7 +295,9 @@ xrep_orphanage_can_adopt(
return false;
if (sc->ip == sc->orphanage)
return false;
- if (xfs_internal_inum(sc->mp, sc->ip->i_ino))
+ if (xchk_inode_is_sb_rooted(sc->ip))
+ return false;
+ if (xfs_is_metadata_inode(sc->ip))
return false;
return true;
}
diff --git a/fs/xfs/scrub/parent.c b/fs/xfs/scrub/parent.c
index 91e7b51ce0680..582536076433a 100644
--- a/fs/xfs/scrub/parent.c
+++ b/fs/xfs/scrub/parent.c
@@ -300,7 +300,7 @@ xchk_parent_pptr_and_dotdot(
}

/* Is this the root dir? Then '..' must point to itself. */
- if (sc->ip == sc->mp->m_rootip) {
+ if (xchk_inode_is_dirtree_root(sc->ip)) {
if (sc->ip->i_ino != pp->parent_ino)
xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
return 0;
@@ -711,7 +711,7 @@ xchk_parent_count_pptrs(
}

if (S_ISDIR(VFS_I(sc->ip)->i_mode)) {
- if (sc->ip == sc->mp->m_rootip)
+ if (xchk_inode_is_dirtree_root(sc->ip))
pp->pptrs_found++;

if (VFS_I(sc->ip)->i_nlink == 0 && pp->pptrs_found > 0)
@@ -885,10 +885,9 @@ bool
xchk_pptr_looks_zapped(
struct xfs_inode *ip)
{
- struct xfs_mount *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);

- ASSERT(xfs_has_parent(mp));
+ ASSERT(xfs_has_parent(ip->i_mount));

/*
* Temporary files that cannot be linked into the directory tree do not
@@ -902,15 +901,15 @@ xchk_pptr_looks_zapped(
* of a parent pointer scan is always the empty set. It's safe to scan
* them even if the attr fork was zapped.
*/
- if (ip == mp->m_rootip)
+ if (xchk_inode_is_dirtree_root(ip))
return false;

/*
- * Metadata inodes are all rooted in the superblock and do not have
- * any parents. Hence the attr fork will not be initialized, but
- * there are no parent pointers that might have been zapped.
+ * Metadata inodes that are rooted in the superblock do not have any
+ * parents. Hence the attr fork will not be initialized, but there are
+ * no parent pointers that might have been zapped.
*/
- if (xfs_is_metadata_inode(ip))
+ if (xchk_inode_is_sb_rooted(ip))
return false;

/*
diff --git a/fs/xfs/scrub/parent_repair.c b/fs/xfs/scrub/parent_repair.c
index 7b42b7f65a0bd..f4e4845b7ec09 100644
--- a/fs/xfs/scrub/parent_repair.c
+++ b/fs/xfs/scrub/parent_repair.c
@@ -1334,7 +1334,7 @@ xrep_parent_rebuild_pptrs(
* so that we can decide if we're moving this file to the orphanage.
* For this purpose, root directories are their own parents.
*/
- if (sc->ip == sc->mp->m_rootip) {
+ if (xchk_inode_is_dirtree_root(sc->ip)) {
xrep_findparent_scan_found(&rp->pscan, sc->ip->i_ino);
} else {
error = xrep_parent_lookup_pptrs(sc, &parent_ino);