Merge tag 'scrub-pptrs-6.10_2024-04-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.10-mergeC

xfs: scrubbing for parent pointers

Teach online fsck to use parent pointers to assist in checking
directories, parent pointers, extended attributes, and link counts.

Signed-off-by: Darrick J. Wong <[email protected]>
Signed-off-by: Chandan Babu R <[email protected]>

* tag 'scrub-pptrs-6.10_2024-04-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: check parent pointer xattrs when scrubbing
  xfs: walk directory parent pointers to determine backref count
  xfs: deferred scrub of parent pointers
  xfs: scrub parent pointers
  xfs: deferred scrub of dirents
  xfs: check dirents have parent pointers
  xfs: revert commit 44af6c7

Author: Chandan Babu R

fs/xfs/Makefile

@@ -177,6 +177,7 @@ xfs-y				+= $(addprefix scrub/, \
 				   scrub.o \
 				   symlink.o \
 				   xfarray.o \
+				   xfblob.o \
 				   xfile.o \
 				   )
 
@@ -218,7 +219,6 @@ xfs-y				+= $(addprefix scrub/, \
 				   rmap_repair.o \
 				   symlink_repair.o \
 				   tempfile.o \
-				   xfblob.o \
 				   )
 
 xfs-$(CONFIG_XFS_RT)		+= $(addprefix scrub/, \

fs/xfs/libxfs/xfs_parent.c

@@ -291,3 +291,25 @@ xfs_parent_from_attr(
 		*parent_gen = be32_to_cpu(rec->p_gen);
 	return 0;
 }
+
+/*
+ * Look up a parent pointer record (@parent_name -> @pptr) of @ip.
+ *
+ * Caller must hold at least ILOCK_SHARED.  The scratchpad need not be
+ * initialized.
+ *
+ * Returns 0 if the pointer is found, -ENOATTR if there is no match, or a
+ * negative errno.
+ */
+int
+xfs_parent_lookup(
+	struct xfs_trans		*tp,
+	struct xfs_inode		*ip,
+	const struct xfs_name		*parent_name,
+	struct xfs_parent_rec		*pptr,
+	struct xfs_da_args		*scratch)
+{
+	memset(scratch, 0, sizeof(struct xfs_da_args));
+	xfs_parent_da_args_init(scratch, tp, pptr, ip, ip->i_ino, parent_name);
+	return xfs_attr_get_ilocked(scratch);
+}

fs/xfs/libxfs/xfs_parent.h

@@ -96,4 +96,9 @@ int xfs_parent_from_attr(struct xfs_mount *mp, unsigned int attr_flags,
 		const void *value, unsigned int valuelen,
 		xfs_ino_t *parent_ino, uint32_t *parent_gen);
 
+/* Repair functions */
+int xfs_parent_lookup(struct xfs_trans *tp, struct xfs_inode *ip,
+		const struct xfs_name *name, struct xfs_parent_rec *pptr,
+		struct xfs_da_args *scratch);
+
 #endif /* __XFS_PARENT_H__ */

fs/xfs/scrub/attr.c

@@ -17,6 +17,7 @@
 #include "xfs_attr.h"
 #include "xfs_attr_leaf.h"
 #include "xfs_attr_sf.h"
+#include "xfs_parent.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
 #include "scrub/dabtree.h"
@@ -208,13 +209,12 @@ xchk_xattr_actor(
 		return -ECANCELED;
 	}
 
-	/*
-	 * Local and shortform xattr values are stored in the attr leaf block,
-	 * so we don't need to retrieve the value from a remote block to detect
-	 * corruption problems.
-	 */
-	if (value)
-		return 0;
+	/* Check parent pointer record. */
+	if ((attr_flags & XFS_ATTR_PARENT) &&
+	    !xfs_parent_valuecheck(sc->mp, value, valuelen)) {
+		xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, args.blkno);
+		return -ECANCELED;
+	}
 
 	/*
 	 * Try to allocate enough memory to extract the attr value.  If that
@@ -227,8 +227,21 @@ xchk_xattr_actor(
 	if (error)
 		return error;
 
+	/*
+	 * Parent pointers are matched on attr name and value, so we must
+	 * supply the xfs_parent_rec here when confirming that the dabtree
+	 * indexing works correctly.
+	 */
+	if (attr_flags & XFS_ATTR_PARENT)
+		memcpy(ab->value, value, valuelen);
+
 	args.value = ab->value;
 
+	/*
+	 * Get the attr value to ensure that lookup can find this attribute
+	 * through the dabtree indexing and that remote value retrieval also
+	 * works correctly.
+	 */
 	xfs_attr_sethash(&args);
 	error = xfs_attr_get_ilocked(&args);
 	/* ENODATA means the hash lookup failed and the attr is bad */

fs/xfs/scrub/common.h

@@ -212,6 +212,7 @@ static inline bool xchk_skip_xref(struct xfs_scrub_metadata *sm)
 }
 
 bool xchk_dir_looks_zapped(struct xfs_inode *dp);
+bool xchk_pptr_looks_zapped(struct xfs_inode *ip);
 
 #ifdef CONFIG_XFS_ONLINE_REPAIR
 /* Decide if a repair is required. */