Merge tag 'repair-symlink-6.10_2024-04-15' of...

Merge tag 'repair-symlink-6.10_2024-04-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.10-mergeA

xfs: online repair of symbolic links

The patches in this set adds the ability to repair the target buffer of
a symbolic link, using the same salvage, rebuild, and swap strategy used
everywhere else.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'repair-symlink-6.10_2024-04-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: online repair of symbolic links
  xfs: pass the owner to xfs_symlink_write_target
  xfs: expose xfs_bmap_local_to_extents for online repair

fs/xfs/Makefile

@@ -213,6 +213,7 @@ xfs-y				+= $(addprefix scrub/, \
 				   refcount_repair.o \
 				   repair.o \
 				   rmap_repair.o \
+				   symlink_repair.o \
 				   tempfile.o \
 				   xfblob.o \
 				   )

fs/xfs/libxfs/xfs_bmap.c

@@ -779,7 +779,7 @@ xfs_bmap_local_to_extents_empty(
 }
 
 
-STATIC int				/* error */
+int					/* error */
 xfs_bmap_local_to_extents(
 	xfs_trans_t	*tp,		/* transaction pointer */
 	xfs_inode_t	*ip,		/* incore inode pointer */
@@ -789,7 +789,8 @@ xfs_bmap_local_to_extents(
 	void		(*init_fn)(struct xfs_trans *tp,
 				   struct xfs_buf *bp,
 				   struct xfs_inode *ip,
-				   struct xfs_ifork *ifp))
+				   struct xfs_ifork *ifp, void *priv),
+	void		*priv)
 {
 	int		error = 0;
 	int		flags;		/* logging flags returned */
@@ -850,7 +851,7 @@ xfs_bmap_local_to_extents(
 	 * log here. Note that init_fn must also set the buffer log item type
 	 * correctly.
 	 */
-	init_fn(tp, bp, ip, ifp);
+	init_fn(tp, bp, ip, ifp, priv);
 
 	/* account for the change in fork size */
 	xfs_idata_realloc(ip, -ifp->if_bytes, whichfork);
@@ -982,8 +983,8 @@ xfs_bmap_add_attrfork_local(
 
 	if (S_ISLNK(VFS_I(ip)->i_mode))
 		return xfs_bmap_local_to_extents(tp, ip, 1, flags,
-						 XFS_DATA_FORK,
-						 xfs_symlink_local_to_remote);
+				XFS_DATA_FORK, xfs_symlink_local_to_remote,
+				NULL);
 
 	/* should only be called for types that support local format data */
 	ASSERT(0);

fs/xfs/libxfs/xfs_bmap.h

@@ -179,6 +179,12 @@ unsigned int xfs_bmap_compute_attr_offset(struct xfs_mount *mp);
 int	xfs_bmap_add_attrfork(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,
+		xfs_extlen_t total, int *logflagsp, int whichfork,
+		void (*init_fn)(struct xfs_trans *tp, struct xfs_buf *bp,
+				struct xfs_inode *ip, struct xfs_ifork *ifp,
+				void *priv),
+		void *priv);
 void	xfs_bmap_compute_maxlevels(struct xfs_mount *mp, int whichfork);
 int	xfs_bmap_first_unused(struct xfs_trans *tp, struct xfs_inode *ip,
 		xfs_extlen_t len, xfs_fileoff_t *unused, int whichfork);

fs/xfs/libxfs/xfs_symlink_remote.c

@@ -169,7 +169,8 @@ xfs_symlink_local_to_remote(
 	struct xfs_trans	*tp,
 	struct xfs_buf		*bp,
 	struct xfs_inode	*ip,
-	struct xfs_ifork	*ifp)
+	struct xfs_ifork	*ifp,
+	void			*priv)
 {
 	struct xfs_mount	*mp = ip->i_mount;
 	char			*buf;
@@ -310,6 +311,7 @@ int
 xfs_symlink_write_target(
 	struct xfs_trans	*tp,
 	struct xfs_inode	*ip,
+	xfs_ino_t		owner,
 	const char		*target_path,
 	int			pathlen,
 	xfs_fsblock_t		fs_blocks,
@@ -364,8 +366,7 @@ xfs_symlink_write_target(
 		byte_cnt = min(byte_cnt, pathlen);
 
 		buf = bp->b_addr;
-		buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, byte_cnt,
-				bp);
+		buf += xfs_symlink_hdr_set(mp, owner, offset, byte_cnt, bp);
 
 		memcpy(buf, cur_chunk, byte_cnt);
 

fs/xfs/libxfs/xfs_symlink_remote.h

@@ -16,12 +16,13 @@ int xfs_symlink_hdr_set(struct xfs_mount *mp, xfs_ino_t ino, uint32_t offset,
 bool xfs_symlink_hdr_ok(xfs_ino_t ino, uint32_t offset,
 			uint32_t size, struct xfs_buf *bp);
 void xfs_symlink_local_to_remote(struct xfs_trans *tp, struct xfs_buf *bp,
-				 struct xfs_inode *ip, struct xfs_ifork *ifp);
+				 struct xfs_inode *ip, struct xfs_ifork *ifp,
+				 void *priv);
 xfs_failaddr_t xfs_symlink_shortform_verify(void *sfp, int64_t size);
 int xfs_symlink_remote_read(struct xfs_inode *ip, char *link);
 int xfs_symlink_write_target(struct xfs_trans *tp, struct xfs_inode *ip,
-		const char *target_path, int pathlen, xfs_fsblock_t fs_blocks,
-		uint resblks);
+		xfs_ino_t owner, const char *target_path, int pathlen,
+		xfs_fsblock_t fs_blocks, uint resblks);
 int xfs_symlink_remote_truncate(struct xfs_trans *tp, struct xfs_inode *ip);
 
 #endif /* __XFS_SYMLINK_REMOTE_H */

fs/xfs/scrub/repair.h

@@ -94,6 +94,7 @@ int xrep_setup_xattr(struct xfs_scrub *sc);
 int xrep_setup_directory(struct xfs_scrub *sc);
 int xrep_setup_parent(struct xfs_scrub *sc);
 int xrep_setup_nlinks(struct xfs_scrub *sc);
+int xrep_setup_symlink(struct xfs_scrub *sc, unsigned int *resblks);
 
 /* Repair setup functions */
 int xrep_setup_ag_allocbt(struct xfs_scrub *sc);
@@ -130,6 +131,7 @@ int xrep_fscounters(struct xfs_scrub *sc);
 int xrep_xattr(struct xfs_scrub *sc);
 int xrep_directory(struct xfs_scrub *sc);
 int xrep_parent(struct xfs_scrub *sc);
+int xrep_symlink(struct xfs_scrub *sc);
 
 #ifdef CONFIG_XFS_RT
 int xrep_rtbitmap(struct xfs_scrub *sc);
@@ -206,6 +208,11 @@ xrep_setup_nothing(
 
 #define xrep_setup_inode(sc, imap)	((void)0)
 
+static inline int xrep_setup_symlink(struct xfs_scrub *sc, unsigned int *x)
+{
+	return 0;
+}
+
 #define xrep_revalidate_allocbt		(NULL)
 #define xrep_revalidate_iallocbt	(NULL)
 
@@ -231,6 +238,7 @@ xrep_setup_nothing(
 #define xrep_xattr			xrep_notsupported
 #define xrep_directory			xrep_notsupported
 #define xrep_parent			xrep_notsupported
+#define xrep_symlink			xrep_notsupported
 
 #endif /* CONFIG_XFS_ONLINE_REPAIR */
 

fs/xfs/scrub/scrub.c

@@ -339,7 +339,7 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
 		.type	= ST_INODE,
 		.setup	= xchk_setup_symlink,
 		.scrub	= xchk_symlink,
-		.repair	= xrep_notsupported,
+		.repair	= xrep_symlink,
 	},
 	[XFS_SCRUB_TYPE_PARENT] = {	/* parent pointers */
 		.type	= ST_INODE,

fs/xfs/scrub/symlink.c

@@ -10,6 +10,7 @@
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_log_format.h"
+#include "xfs_trans.h"
 #include "xfs_inode.h"
 #include "xfs_symlink.h"
 #include "xfs_health.h"
@@ -17,18 +18,28 @@
 #include "scrub/scrub.h"
 #include "scrub/common.h"
 #include "scrub/health.h"
+#include "scrub/repair.h"
 
 /* Set us up to scrub a symbolic link. */
 int
 xchk_setup_symlink(
 	struct xfs_scrub	*sc)
 {
+	unsigned int		resblks = 0;
+	int			error;
+
 	/* Allocate the buffer without the inode lock held. */
 	sc->buf = kvzalloc(XFS_SYMLINK_MAXLEN + 1, XCHK_GFP_FLAGS);
 	if (!sc->buf)
 		return -ENOMEM;
 
-	return xchk_setup_inode_contents(sc, 0);
+	if (xchk_could_repair(sc)) {
+		error = xrep_setup_symlink(sc, &resblks);
+		if (error)
+			return error;
+	}
+
+	return xchk_setup_inode_contents(sc, resblks);
 }
 
 /* Symbolic links. */

fs/xfs/scrub/tempfile.c

@@ -21,6 +21,7 @@
 #include "xfs_exchrange.h"
 #include "xfs_exchmaps.h"
 #include "xfs_defer.h"
+#include "xfs_symlink_remote.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
 #include "scrub/repair.h"
@@ -109,6 +110,18 @@ xrep_tempfile_create(
 		error = xfs_dir_init(tp, sc->tempip, dp);
 		if (error)
 			goto out_trans_cancel;
+	} else if (S_ISLNK(VFS_I(sc->tempip)->i_mode)) {
+		/*
+		 * Initialize the temporary symlink with a meaningless target
+		 * that won't trip the verifiers.  Repair must rewrite the
+		 * target with meaningful content before swapping with the file
+		 * being repaired.  A single-byte target will not write a
+		 * remote target block, so the owner is irrelevant.
+		 */
+		error = xfs_symlink_write_target(tp, sc->tempip,
+				sc->tempip->i_ino, ".", 1, 0, 0);
+		if (error)
+			goto out_trans_cancel;
 	}
 
 	/*

fs/xfs/scrub/trace.h

@@ -2711,6 +2711,52 @@ DEFINE_REPAIR_DENTRY_EVENT(xrep_adoption_check_alias);
 DEFINE_REPAIR_DENTRY_EVENT(xrep_adoption_check_dentry);
 DEFINE_REPAIR_DENTRY_EVENT(xrep_adoption_invalidate_child);
 
+TRACE_EVENT(xrep_symlink_salvage_target,
+	TP_PROTO(struct xfs_inode *ip, char *target, unsigned int targetlen),
+	TP_ARGS(ip, target, targetlen),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_ino_t, ino)
+		__field(unsigned int, targetlen)
+		__dynamic_array(char, target, targetlen + 1)
+	),
+	TP_fast_assign(
+		__entry->dev = ip->i_mount->m_super->s_dev;
+		__entry->ino = ip->i_ino;
+		__entry->targetlen = targetlen;
+		memcpy(__get_str(target), target, targetlen);
+		__get_str(target)[targetlen] = 0;
+	),
+	TP_printk("dev %d:%d ip 0x%llx target '%.*s'",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino,
+		  __entry->targetlen,
+		  __get_str(target))
+);
+
+DECLARE_EVENT_CLASS(xrep_symlink_class,
+	TP_PROTO(struct xfs_inode *ip),
+	TP_ARGS(ip),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_ino_t, ino)
+	),
+	TP_fast_assign(
+		__entry->dev = ip->i_mount->m_super->s_dev;
+		__entry->ino = ip->i_ino;
+	),
+	TP_printk("dev %d:%d ip 0x%llx",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino)
+);
+
+#define DEFINE_XREP_SYMLINK_EVENT(name) \
+DEFINE_EVENT(xrep_symlink_class, name, \
+	TP_PROTO(struct xfs_inode *ip), \
+	TP_ARGS(ip))
+DEFINE_XREP_SYMLINK_EVENT(xrep_symlink_rebuild);
+DEFINE_XREP_SYMLINK_EVENT(xrep_symlink_reset_fork);
+
 #endif /* IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR) */
 
 #endif /* _TRACE_XFS_SCRUB_TRACE_H */

fs/xfs/xfs_symlink.c

@@ -181,8 +181,8 @@ xfs_symlink(
 	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
 
 	resblks -= XFS_IALLOC_SPACE_RES(mp);
-	error = xfs_symlink_write_target(tp, ip, target_path, pathlen,
-			fs_blocks, resblks);
+	error = xfs_symlink_write_target(tp, ip, ip->i_ino, target_path,
+			pathlen, fs_blocks, resblks);
 	if (error)
 		goto out_trans_cancel;
 	resblks -= fs_blocks;