From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Repair inconsistent symbolic link data.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/Makefile | 1
fs/xfs/scrub/repair.h | 2
fs/xfs/scrub/scrub.c | 2
fs/xfs/scrub/symlink.c | 5 +
fs/xfs/scrub/symlink_repair.c | 244 +++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_symlink.c | 150 ++++++++++++++-----------
fs/xfs/xfs_symlink.h | 3 +
7 files changed, 339 insertions(+), 68 deletions(-)
create mode 100644 fs/xfs/scrub/symlink_repair.c
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 7f5467bb18b9..e25cde969d99 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -171,6 +171,7 @@ xfs-y += $(addprefix scrub/, \
inode_repair.o \
refcount_repair.o \
repair.o \
+ symlink_repair.o \
)
endif
endif
diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
index 38444fec70db..17769efb20d9 100644
--- a/fs/xfs/scrub/repair.h
+++ b/fs/xfs/scrub/repair.h
@@ -68,6 +68,7 @@ int xrep_refcountbt(struct xfs_scrub *sc);
int xrep_inode(struct xfs_scrub *sc);
int xrep_bmap_data(struct xfs_scrub *sc);
int xrep_bmap_attr(struct xfs_scrub *sc);
+int xrep_symlink(struct xfs_scrub *sc);
#else
@@ -108,6 +109,7 @@ xrep_reset_perag_resv(
#define xrep_inode xrep_notsupported
#define xrep_bmap_data xrep_notsupported
#define xrep_bmap_attr xrep_notsupported
+#define xrep_symlink xrep_notsupported
#endif /* CONFIG_XFS_ONLINE_REPAIR */
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 45af20a3ab50..0a8eea77e58f 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -307,7 +307,7 @@ 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,
diff --git a/fs/xfs/scrub/symlink.c b/fs/xfs/scrub/symlink.c
index f7ebaa946999..ee968c62d0f2 100644
--- a/fs/xfs/scrub/symlink.c
+++ b/fs/xfs/scrub/symlink.c
@@ -29,12 +29,15 @@ xchk_setup_symlink(
struct xfs_scrub *sc,
struct xfs_inode *ip)
{
+ uint resblks;
+
/* Allocate the buffer without the inode lock held. */
sc->buf = kmem_zalloc_large(XFS_SYMLINK_MAXLEN + 1, KM_SLEEP);
if (!sc->buf)
return -ENOMEM;
- return xchk_setup_inode_contents(sc, ip, 0);
+ resblks = xfs_symlink_blocks(sc->mp, XFS_SYMLINK_MAXLEN);
+ return xchk_setup_inode_contents(sc, ip, resblks);
}
/* Symbolic links. */
diff --git a/fs/xfs/scrub/symlink_repair.c b/fs/xfs/scrub/symlink_repair.c
new file mode 100644
index 000000000000..6888094cf941
--- /dev/null
+++ b/fs/xfs/scrub/symlink_repair.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_inode_fork.h"
+#include "xfs_symlink.h"
+#include "xfs_bmap.h"
+#include "xfs_quota.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_trans_space.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+#include "scrub/repair.h"
+
+/*
+ * Symbolic Link Repair
+ * ====================
+ *
+ * There's not much we can do to repair symbolic links -- we truncate them to
+ * the first NULL byte and reinitialize the target. Zero-length symlinks are
+ * turned into links to the current dir.
+ */
+
+/* Try to salvage the pathname from rmt blocks. */
+STATIC int
+xrep_symlink_salvage_remote(
+ struct xfs_scrub *sc)
+{
+ struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
+ struct xfs_inode *ip = sc->ip;
+ struct xfs_buf *bp;
+ char *target_buf = sc->buf;
+ xfs_failaddr_t fa;
+ xfs_filblks_t fsblocks;
+ xfs_daddr_t d;
+ loff_t len;
+ loff_t offset;
+ unsigned int byte_cnt;
+ bool magic_ok;
+ bool hdr_ok;
+ int n;
+ int nmaps = XFS_SYMLINK_MAPS;
+ int error;
+
+ /* We'll only read until the buffer is full. */
+ len = max_t(loff_t, ip->i_d.di_size, XFS_SYMLINK_MAXLEN);
+ fsblocks = xfs_symlink_blocks(sc->mp, len);
+ error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
+ if (error)
+ return error;
+
+ offset = 0;
+ for (n = 0; n < nmaps; n++) {
+ struct xfs_dsymlink_hdr *dsl;
+
+ d = XFS_FSB_TO_DADDR(sc->mp, mval[n].br_startblock);
+
+ /* Read the rmt block. We'll run the verifiers manually. */
+ error = xfs_trans_read_buf(sc->mp, sc->tp, sc->mp->m_ddev_targp,
+ d, XFS_FSB_TO_BB(sc->mp, mval[n].br_blockcount),
+ 0, &bp, NULL);
+ if (error)
+ return error;
+ bp->b_ops = &xfs_symlink_buf_ops;
+
+ /* How many bytes do we expect to get out of this buffer? */
+ byte_cnt = XFS_FSB_TO_B(sc->mp, mval[n].br_blockcount);
+ byte_cnt = XFS_SYMLINK_BUF_SPACE(sc->mp, byte_cnt);
+ byte_cnt = min_t(unsigned int, byte_cnt, len);
+
+ /*
+ * See if the verifiers accept this block. We're willing to
+ * salvage if the if the offset/byte/ino are ok and either the
+ * verifier passed or the magic is ok. Anything else and we
+ * stop dead in our tracks.
+ */
+ fa = bp->b_ops->verify_struct(bp);
+ dsl = bp->b_addr;
+ magic_ok = dsl->sl_magic == cpu_to_be32(XFS_SYMLINK_MAGIC);
+ hdr_ok = xfs_symlink_hdr_ok(ip->i_ino, offset, byte_cnt, bp);
+ if (!hdr_ok || (fa != NULL && !magic_ok))
+ break;
+
+ memcpy(target_buf + offset, dsl + 1, byte_cnt);
+
+ len -= byte_cnt;
+ offset += byte_cnt;
+ }
+
+ /* Ensure we have a zero at the end, and /some/ contents. */
+ if (offset == 0)
+ sprintf(target_buf, ".");
+ else
+ target_buf[offset] = 0;
+ return 0;
+}
+
+/*
+ * Try to salvage an inline symlink's contents. Empty symlinks become a link
+ * to the current directory.
+ */
+STATIC void
+xrep_symlink_salvage_inline(
+ struct xfs_scrub *sc)
+{
+ struct xfs_inode *ip = sc->ip;
+ struct xfs_ifork *ifp;
+
+ ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
+ if (ifp->if_u1.if_data)
+ strncpy(sc->buf, ifp->if_u1.if_data, XFS_IFORK_DSIZE(ip));
+ if (strlen(sc->buf) == 0)
+ sprintf(sc->buf, ".");
+}
+
+/* Reset an inline symlink to its fresh configuration. */
+STATIC void
+xrep_symlink_truncate_inline(
+ struct xfs_inode *ip)
+{
+ xfs_idestroy_fork(ip, XFS_DATA_FORK);
+ ip->i_d.di_format = XFS_DINODE_FMT_EXTENTS;
+ ip->i_d.di_nextents = 0;
+ memset(&ip->i_df, 0, sizeof(struct xfs_ifork));
+ ip->i_df.if_flags |= XFS_IFEXTENTS;
+}
+
+/*
+ * Salvage an inline symlink's contents and reset data fork.
+ * Returns with the inode joined to the transaction.
+ */
+STATIC int
+xrep_symlink_inline(
+ struct xfs_scrub *sc)
+{
+ /* Salvage whatever link target information we can find. */
+ xrep_symlink_salvage_inline(sc);
+
+ /* Truncate the symlink. */
+ xrep_symlink_truncate_inline(sc->ip);
+
+ xfs_trans_ijoin(sc->tp, sc->ip, 0);
+ return 0;
+}
+
+/*
+ * Salvage an inline symlink's contents and reset data fork.
+ * Returns with the inode joined to the transaction.
+ */
+STATIC int
+xrep_symlink_remote(
+ struct xfs_scrub *sc)
+{
+ int error;
+
+ /* Salvage whatever link target information we can find. */
+ error = xrep_symlink_salvage_remote(sc);
+ if (error)
+ return error;
+
+ /* Truncate the symlink. */
+ xfs_trans_ijoin(sc->tp, sc->ip, 0);
+ return xfs_itruncate_extents(&sc->tp, sc->ip, XFS_DATA_FORK, 0);
+}
+
+/*
+ * Reinitialize a link target. Caller must ensure the inode is joined to
+ * the transaction.
+ */
+STATIC int
+xrep_symlink_reinitialize(
+ struct xfs_scrub *sc)
+{
+ xfs_fsblock_t fs_blocks;
+ unsigned int target_len;
+ uint resblks;
+ int error;
+
+ /* How many blocks do we need? */
+ target_len = strlen(sc->buf);
+ ASSERT(target_len != 0);
+ if (target_len == 0 || target_len > XFS_SYMLINK_MAXLEN)
+ return -EFSCORRUPTED;
+
+ /* Set up to reinitialize the target. */
+ fs_blocks = xfs_symlink_blocks(sc->mp, target_len);
+ resblks = XFS_SYMLINK_SPACE_RES(sc->mp, target_len, fs_blocks);
+ error = xfs_trans_reserve_quota_nblks(sc->tp, sc->ip, resblks, 0,
+ XFS_QMOPT_RES_REGBLKS);
+
+ /* Try to write the new target back out. */
+ xfs_defer_ijoin(sc->tp->t_dfops, sc->ip);
+ error = xfs_symlink_write_target(sc->tp, sc->ip, sc->buf, target_len,
+ fs_blocks, resblks);
+ if (error)
+ return error;
+
+ /* Finish up any block mapping activities. */
+ return xfs_defer_finish(&sc->tp);
+}
+
+/* Repair a symbolic link. */
+int
+xrep_symlink(
+ struct xfs_scrub *sc)
+{
+ struct xfs_ifork *ifp;
+ int error;
+
+ error = xfs_qm_dqattach_locked(sc->ip, false);
+ if (error)
+ return error;
+
+ /* Salvage whatever we can of the target. */
+ *((char *)sc->buf) = 0;
+ ifp = XFS_IFORK_PTR(sc->ip, XFS_DATA_FORK);
+ if (ifp->if_flags & XFS_IFINLINE)
+ error = xrep_symlink_inline(sc);
+ else
+ error = xrep_symlink_remote(sc);
+ if (error)
+ return error;
+
+ /* Now reset the target. */
+ return xrep_symlink_reinitialize(sc);
+}
diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
index 2bfe7fbbedb2..1097d9062ef3 100644
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -150,6 +150,86 @@ xfs_readlink(
return error;
}
+/* Write the symlink target into the inode. */
+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)
+{
+ struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
+ struct xfs_mount *mp = tp->t_mountp;
+ const char *cur_chunk;
+ struct xfs_buf *bp;
+ xfs_daddr_t d;
+ int byte_cnt;
+ int nmaps;
+ int offset;
+ int n;
+ int error;
+
+ /*
+ * If the symlink will fit into the inode, write it inline.
+ */
+ if (pathlen <= XFS_IFORK_DSIZE(ip)) {
+ xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
+
+ ip->i_d.di_size = pathlen;
+ ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
+ xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
+
+ return 0;
+ }
+
+ /* Write target to remote blocks. */
+ nmaps = XFS_SYMLINK_MAPS;
+ error = xfs_bmapi_write(tp, ip, 0, fs_blocks, XFS_BMAPI_METADATA,
+ resblks, mval, &nmaps);
+ if (error)
+ return error;
+
+ if (resblks)
+ resblks -= fs_blocks;
+ ip->i_d.di_size = pathlen;
+ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+ cur_chunk = target_path;
+ offset = 0;
+ for (n = 0; n < nmaps; n++) {
+ char *buf;
+
+ d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
+ byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
+ bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
+ BTOBB(byte_cnt), 0);
+ if (!bp)
+ return -ENOMEM;
+ bp->b_ops = &xfs_symlink_buf_ops;
+
+ byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
+ byte_cnt = min(byte_cnt, pathlen);
+
+ buf = bp->b_addr;
+ buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
+ byte_cnt, bp);
+
+ memcpy(buf, cur_chunk, byte_cnt);
+
+ cur_chunk += byte_cnt;
+ pathlen -= byte_cnt;
+ offset += byte_cnt;
+
+ xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
+ xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
+ (char *)bp->b_addr);
+ }
+ ASSERT(pathlen == 0);
+ return 0;
+}
+
int
xfs_symlink(
struct xfs_inode *dp,
@@ -164,15 +244,7 @@ xfs_symlink(
int error = 0;
int pathlen;
bool unlock_dp_on_error = false;
- xfs_fileoff_t first_fsb;
xfs_filblks_t fs_blocks;
- int nmaps;
- struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
- xfs_daddr_t d;
- const char *cur_chunk;
- int byte_cnt;
- int n;
- xfs_buf_t *bp;
prid_t prid;
struct xfs_dquot *udqp = NULL;
struct xfs_dquot *gdqp = NULL;
@@ -265,65 +337,11 @@ xfs_symlink(
if (resblks)
resblks -= XFS_IALLOC_SPACE_RES(mp);
- /*
- * If the symlink will fit into the inode, write it inline.
- */
- if (pathlen <= XFS_IFORK_DSIZE(ip)) {
- xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
-
- ip->i_d.di_size = pathlen;
- ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
- xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
- } else {
- int offset;
-
- first_fsb = 0;
- nmaps = XFS_SYMLINK_MAPS;
-
- error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
- XFS_BMAPI_METADATA, resblks, mval, &nmaps);
- if (error)
- goto out_trans_cancel;
-
- if (resblks)
- resblks -= fs_blocks;
- ip->i_d.di_size = pathlen;
- xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
-
- cur_chunk = target_path;
- offset = 0;
- for (n = 0; n < nmaps; n++) {
- char *buf;
-
- d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
- byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
- bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
- BTOBB(byte_cnt), 0);
- if (!bp) {
- error = -ENOMEM;
- goto out_trans_cancel;
- }
- bp->b_ops = &xfs_symlink_buf_ops;
-
- byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
- byte_cnt = min(byte_cnt, pathlen);
-
- buf = bp->b_addr;
- buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
- byte_cnt, bp);
-
- memcpy(buf, cur_chunk, byte_cnt);
- cur_chunk += byte_cnt;
- pathlen -= byte_cnt;
- offset += byte_cnt;
-
- xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
- xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
- (char *)bp->b_addr);
- }
- ASSERT(pathlen == 0);
- }
+ error = xfs_symlink_write_target(tp, ip, target_path, pathlen,
+ fs_blocks, resblks);
+ if (error)
+ goto out_trans_cancel;
/*
* Create the directory entry for the symlink.
diff --git a/fs/xfs/xfs_symlink.h b/fs/xfs/xfs_symlink.h
index 9743d8c9394b..d7252f9cab41 100644
--- a/fs/xfs/xfs_symlink.h
+++ b/fs/xfs/xfs_symlink.h
@@ -12,5 +12,8 @@ int xfs_symlink(struct xfs_inode *dp, struct xfs_name *link_name,
int xfs_readlink_bmap_ilocked(struct xfs_inode *ip, char *link);
int xfs_readlink(struct xfs_inode *ip, char *link);
int xfs_inactive_symlink(struct xfs_inode *ip);
+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);
#endif /* __XFS_SYMLINK_H */
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