Merge tag 'repair-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: online repair for parent pointers

This series implements online repair for directory parent pointer
metadata.  The checking half is fairly straightforward -- for each
outgoing directory link (forward or backwards), grab the inode at the
other end, and confirm that there's a corresponding link.  If we can't
grab an inode or lock it, we'll save that link for a slower loop that
cycles all the locks, confirms the continued existence of the link, and
rechecks the link if it's actually still there.

Repairs are a bit more involved -- for directories, we walk the entire
filesystem to rebuild the dirents from parent pointer information.
Parent pointer repairs do the same walk but rebuild the pptrs from the
dirent information, but with the added twist that it duplicates all the
xattrs so that it can use the atomic extent swapping code to commit the
repairs atomically.

This introduces an added twist to the xattr repair code -- we use dirent
hooks to detect a colliding update to the pptr data while we're not
holding the ILOCKs; if one is detected, we restart the xattr salvaging
process but this time hold all the ILOCKs until the end of the scan.

For offline repair, the phase6 directory connectivity scan generates an
index of all the expected parent pointers in the filesystem.  Then it
walks each file and compares the parent pointers attached to that file
against the index generated, and resyncs the results as necessary.

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

* tag 'repair-pptrs-6.10_2024-04-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: inode repair should ensure there's an attr fork to store parent pointers
  xfs: repair link count of nondirectories after rebuilding parent pointers
  xfs: adapt the orphanage code to handle parent pointers
  xfs: actually rebuild the parent pointer xattrs
  xfs: add a per-leaf block callback to xchk_xattr_walk
  xfs: split xfs_bmap_add_attrfork into two pieces
  xfs: remove pointless unlocked assertion
  xfs: implement live updates for parent pointer repairs
  xfs: repair directory parent pointers by scanning for dirents
  xfs: replay unlocked parent pointer updates that accrue during xattr repair
  xfs: implement live updates for directory repairs
  xfs: repair directories by scanning directory parent pointers
  xfs: add raw parent pointer apis to support repair
  xfs: salvage parent pointers when rebuilding xattr structures
  xfs: make the reserved block permission flag explicit in xfs_attr_set
  xfs: remove some boilerplate from xfs_attr_set

Author: Chandan Babu R

fs/xfs/libxfs/xfs_attr.c

@@ -948,40 +948,67 @@ xfs_attr_lookup(
 	return error;
 }
 
+int
+xfs_attr_add_fork(
+	struct xfs_inode	*ip,		/* incore inode pointer */
+	int			size,		/* space new attribute needs */
+	int			rsvd)		/* xact may use reserved blks */
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;		/* transaction pointer */
+	unsigned int		blks;		/* space reservation */
+	int			error;		/* error return value */
+
+	ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
+
+	blks = XFS_ADDAFORK_SPACE_RES(mp);
+
+	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_addafork, blks, 0,
+			rsvd, &tp);
+	if (error)
+		return error;
+
+	if (xfs_inode_has_attr_fork(ip))
+		goto trans_cancel;
+
+	error = xfs_bmap_add_attrfork(tp, ip, size, rsvd);
+	if (error)
+		goto trans_cancel;
+
+	error = xfs_trans_commit(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+
+trans_cancel:
+	xfs_trans_cancel(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+/*
+ * Make a change to the xattr structure.
+ *
+ * The caller must have initialized @args, attached dquots, and must not hold
+ * any ILOCKs.  Reserved data blocks may be used if @rsvd is set.
+ *
+ * Returns -EEXIST for XFS_ATTRUPDATE_CREATE if the name already exists.
+ * Returns -ENOATTR for XFS_ATTRUPDATE_REMOVE if the name does not exist.
+ * Returns 0 on success, or a negative errno if something else went wrong.
+ */
 int
 xfs_attr_set(
 	struct xfs_da_args	*args,
-	enum xfs_attr_update	op)
+	enum xfs_attr_update	op,
+	bool			rsvd)
 {
 	struct xfs_inode	*dp = args->dp;
 	struct xfs_mount	*mp = dp->i_mount;
 	struct xfs_trans_res	tres;
-	bool			rsvd = (args->attr_filter & XFS_ATTR_ROOT);
 	int			error, local;
 	int			rmt_blks = 0;
 	unsigned int		total;
 
-	if (xfs_is_shutdown(dp->i_mount))
-		return -EIO;
-
-	error = xfs_qm_dqattach(dp);
-	if (error)
-		return error;
-
-	if (!args->owner)
-		args->owner = args->dp->i_ino;
-	args->geo = mp->m_attr_geo;
-	args->whichfork = XFS_ATTR_FORK;
-	xfs_attr_sethash(args);
-
-	/*
-	 * We have no control over the attribute names that userspace passes us
-	 * to remove, so we have to allow the name lookup prior to attribute
-	 * removal to fail as well.  Preserve the logged flag, since we need
-	 * to pass that through to the logging code.
-	 */
-	args->op_flags = XFS_DA_OP_OKNOENT |
-					(args->op_flags & XFS_DA_OP_LOGGED);
+	ASSERT(!args->trans);
 
 	switch (op) {
 	case XFS_ATTRUPDATE_UPSERT:
@@ -999,7 +1026,7 @@ xfs_attr_set(
 				xfs_attr_sf_entsize_byname(args->namelen,
 						args->valuelen);
 
-			error = xfs_bmap_add_attrfork(dp, sf_size, rsvd);
+			error = xfs_attr_add_fork(dp, sf_size, rsvd);
 			if (error)
 				return error;
 		}
@@ -1076,6 +1103,7 @@ xfs_attr_set(
 	error = xfs_trans_commit(args->trans);
 out_unlock:
 	xfs_iunlock(dp, XFS_ILOCK_EXCL);
+	args->trans = NULL;
 	return error;
 
 out_trans_cancel:

fs/xfs/libxfs/xfs_attr.h

@@ -558,7 +558,7 @@ enum xfs_attr_update {
 	XFS_ATTRUPDATE_REPLACE,	/* set value, fail if attr does not exist */
 };
 
-int xfs_attr_set(struct xfs_da_args *args, enum xfs_attr_update op);
+int xfs_attr_set(struct xfs_da_args *args, enum xfs_attr_update op, bool rsvd);
 int xfs_attr_set_iter(struct xfs_attr_intent *attr);
 int xfs_attr_remove_iter(struct xfs_attr_intent *attr);
 bool xfs_attr_check_namespace(unsigned int attr_flags);
@@ -648,5 +648,6 @@ int __init xfs_attr_intent_init_cache(void);
 void xfs_attr_intent_destroy_cache(void);
 
 int xfs_attr_sf_totsize(struct xfs_inode *dp);
+int xfs_attr_add_fork(struct xfs_inode *ip, int size, int rsvd);
 
 #endif	/* __XFS_ATTR_H__ */

fs/xfs/libxfs/xfs_bmap.c

@@ -1025,40 +1025,29 @@ xfs_bmap_set_attrforkoff(
 }
 
 /*
- * Convert inode from non-attributed to attributed.
- * Must not be in a transaction, ip must not be locked.
+ * Convert inode from non-attributed to attributed.  Caller must hold the
+ * ILOCK_EXCL and the file cannot have an attr fork.
  */
 int						/* error code */
 xfs_bmap_add_attrfork(
-	xfs_inode_t		*ip,		/* incore inode pointer */
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip,		/* incore inode pointer */
 	int			size,		/* space new attribute needs */
 	int			rsvd)		/* xact may use reserved blks */
 {
-	xfs_mount_t		*mp;		/* mount structure */
-	xfs_trans_t		*tp;		/* transaction pointer */
-	int			blks;		/* space reservation */
+	struct xfs_mount	*mp = tp->t_mountp;
 	int			version = 1;	/* superblock attr version */
 	int			logflags;	/* logging flags */
 	int			error;		/* error return value */
 
-	ASSERT(xfs_inode_has_attr_fork(ip) == 0);
-
-	mp = ip->i_mount;
+	xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
 	ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
-
-	blks = XFS_ADDAFORK_SPACE_RES(mp);
-
-	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_addafork, blks, 0,
-			rsvd, &tp);
-	if (error)
-		return error;
-	if (xfs_inode_has_attr_fork(ip))
-		goto trans_cancel;
+	ASSERT(!xfs_inode_has_attr_fork(ip));
 
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 	error = xfs_bmap_set_attrforkoff(ip, size, &version);
 	if (error)
-		goto trans_cancel;
+		return error;
 
 	xfs_ifork_init_attr(ip, XFS_DINODE_FMT_EXTENTS, 0);
 	logflags = 0;
@@ -1079,7 +1068,7 @@ xfs_bmap_add_attrfork(
 	if (logflags)
 		xfs_trans_log_inode(tp, ip, logflags);
 	if (error)
-		goto trans_cancel;
+		return error;
 	if (!xfs_has_attr(mp) ||
 	   (!xfs_has_attr2(mp) && version == 2)) {
 		bool log_sb = false;
@@ -1098,14 +1087,7 @@ xfs_bmap_add_attrfork(
 			xfs_log_sb(tp);
 	}
 
-	error = xfs_trans_commit(tp);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
-	return error;
-
-trans_cancel:
-	xfs_trans_cancel(tp);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
-	return error;
+	return 0;
 }
 
 /*

fs/xfs/libxfs/xfs_bmap.h

@@ -176,7 +176,8 @@ int	xfs_bmap_longest_free_extent(struct xfs_perag *pag,
 void	xfs_trim_extent(struct xfs_bmbt_irec *irec, xfs_fileoff_t bno,
 		xfs_filblks_t len);
 unsigned int xfs_bmap_compute_attr_offset(struct xfs_mount *mp);
-int	xfs_bmap_add_attrfork(struct xfs_inode *ip, int size, int rsvd);
+int	xfs_bmap_add_attrfork(struct xfs_trans *tp, struct xfs_inode *ip,
+		int size, int rsvd);
 void	xfs_bmap_local_to_extents_empty(struct xfs_trans *tp,
 		struct xfs_inode *ip, int whichfork);
 int xfs_bmap_local_to_extents(struct xfs_trans *tp, struct xfs_inode *ip,

fs/xfs/libxfs/xfs_dir2.c

@@ -434,7 +434,7 @@ int
 xfs_dir_removename(
 	struct xfs_trans	*tp,
 	struct xfs_inode	*dp,
-	struct xfs_name		*name,
+	const struct xfs_name	*name,
 	xfs_ino_t		ino,
 	xfs_extlen_t		total)		/* bmap's total block count */
 {

fs/xfs/libxfs/xfs_dir2.h

@@ -58,7 +58,7 @@ extern int xfs_dir_lookup(struct xfs_trans *tp, struct xfs_inode *dp,
 				const struct xfs_name *name, xfs_ino_t *inum,
 				struct xfs_name *ci_name);
 extern int xfs_dir_removename(struct xfs_trans *tp, struct xfs_inode *dp,
-				struct xfs_name *name, xfs_ino_t ino,
+				const struct xfs_name *name, xfs_ino_t ino,
 				xfs_extlen_t tot);
 extern int xfs_dir_replace(struct xfs_trans *tp, struct xfs_inode *dp,
 				const struct xfs_name *name, xfs_ino_t inum,

fs/xfs/libxfs/xfs_parent.c

@@ -313,3 +313,67 @@ xfs_parent_lookup(
 	xfs_parent_da_args_init(scratch, tp, pptr, ip, ip->i_ino, parent_name);
 	return xfs_attr_get_ilocked(scratch);
 }
+
+/* Sanity-check a parent pointer before we try to perform repairs. */
+static inline bool
+xfs_parent_sanity_check(
+	struct xfs_mount		*mp,
+	const struct xfs_name		*parent_name,
+	const struct xfs_parent_rec	*pptr)
+{
+	if (!xfs_parent_namecheck(XFS_ATTR_PARENT, parent_name->name,
+				parent_name->len))
+		return false;
+
+	if (!xfs_parent_valuecheck(mp, pptr, sizeof(*pptr)))
+		return false;
+
+	return true;
+}
+
+
+/*
+ * Attach the parent pointer (@parent_name -> @pptr) to @ip immediately.
+ * Caller must not have a transaction or hold the ILOCK.  This is for
+ * specialized repair functions only.  The scratchpad need not be initialized.
+ */
+int
+xfs_parent_set(
+	struct xfs_inode	*ip,
+	xfs_ino_t		owner,
+	const struct xfs_name	*parent_name,
+	struct xfs_parent_rec	*pptr,
+	struct xfs_da_args	*scratch)
+{
+	if (!xfs_parent_sanity_check(ip->i_mount, parent_name, pptr)) {
+		ASSERT(0);
+		return -EFSCORRUPTED;
+	}
+
+	memset(scratch, 0, sizeof(struct xfs_da_args));
+	xfs_parent_da_args_init(scratch, NULL, pptr, ip, owner, parent_name);
+	return xfs_attr_set(scratch, XFS_ATTRUPDATE_CREATE, false);
+}
+
+/*
+ * Remove the parent pointer (@parent_name -> @pptr) from @ip immediately.
+ * Caller must not have a transaction or hold the ILOCK.  This is for
+ * specialized repair functions only.  The scratchpad need not be initialized.
+ */
+int
+xfs_parent_unset(
+	struct xfs_inode		*ip,
+	xfs_ino_t			owner,
+	const struct xfs_name		*parent_name,
+	struct xfs_parent_rec		*pptr,
+	struct xfs_da_args		*scratch)
+{
+	if (!xfs_parent_sanity_check(ip->i_mount, parent_name, pptr)) {
+		ASSERT(0);
+		return -EFSCORRUPTED;
+	}
+
+	memset(scratch, 0, sizeof(struct xfs_da_args));
+	xfs_parent_da_args_init(scratch, NULL, pptr, ip, owner, parent_name);
+	return xfs_attr_set(scratch, XFS_ATTRUPDATE_REMOVE, false);
+}

fs/xfs/libxfs/xfs_parent.h

@@ -100,5 +100,11 @@ int xfs_parent_from_attr(struct xfs_mount *mp, unsigned int attr_flags,
 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);
+int xfs_parent_set(struct xfs_inode *ip, xfs_ino_t owner,
+		const struct xfs_name *name, struct xfs_parent_rec *pptr,
+		struct xfs_da_args *scratch);
+int xfs_parent_unset(struct xfs_inode *ip, xfs_ino_t owner,
+		const struct xfs_name *name, struct xfs_parent_rec *pptr,
+		struct xfs_da_args *scratch);
 
 #endif /* __XFS_PARENT_H__ */

fs/xfs/scrub/attr.c

@@ -675,7 +675,7 @@ xchk_xattr(
 	 * iteration, which doesn't really follow the usual buffer
 	 * locking order.
 	 */
-	error = xchk_xattr_walk(sc, sc->ip, xchk_xattr_actor, NULL);
+	error = xchk_xattr_walk(sc, sc->ip, xchk_xattr_actor, NULL, NULL);
 	if (!xchk_fblock_process_error(sc, XFS_ATTR_FORK, 0, &error))
 		return error;