[PATCH 2/4] xfs: move remote symlink target read function to libxfs

Darrick J. Wong
2023-12-31T22:26:32Z

Move xfs_readlink_bmap_ilocked to xfs_symlink_remote.c so that the
swapext code can use it to convert a remote format symlink back to
shortform format after a metadata repair. While we're at it, fix a
broken printf prefix.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
libxfs/xfs_symlink_remote.c | 77 +++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_symlink_remote.h | 1 +
2 files changed, 78 insertions(+)

diff --git a/libxfs/xfs_symlink_remote.c b/libxfs/xfs_symlink_remote.c
index a989ce2f3f2..8f251ae6799 100644
--- a/libxfs/xfs_symlink_remote.c
+++ b/libxfs/xfs_symlink_remote.c
@@ -14,6 +14,9 @@
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_symlink_remote.h"
+#include "xfs_bit.h"
+#include "xfs_bmap.h"
+#include "xfs_health.h"

/*
* Each contiguous block has a header, so it is not just a simple pathlen
@@ -224,3 +227,77 @@ xfs_symlink_shortform_verify(
return __this_address;
return NULL;
}
+
+/* Read a remote symlink target into the buffer. */
+int
+xfs_symlink_remote_read(
+ struct xfs_inode *ip,
+ char *link)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
+ struct xfs_buf *bp;
+ xfs_daddr_t d;
+ char *cur_chunk;
+ int pathlen = ip->i_disk_size;
+ int nmaps = XFS_SYMLINK_MAPS;
+ int byte_cnt;
+ int n;
+ int error = 0;
+ int fsblocks = 0;
+ int offset;
+
+ ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+
+ fsblocks = xfs_symlink_blocks(mp, pathlen);
+ error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
+ if (error)
+ goto out;
+
+ offset = 0;
+ for (n = 0; n < nmaps; n++) {
+ d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
+ byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
+
+ error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
+ &bp, &xfs_symlink_buf_ops);
+ if (xfs_metadata_is_sick(error))
+ xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
+ if (error)
+ return error;
+ byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
+ if (pathlen < byte_cnt)
+ byte_cnt = pathlen;
+
+ cur_chunk = bp->b_addr;
+ if (xfs_has_crc(mp)) {
+ if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
+ byte_cnt, bp)) {
+ xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
+ error = -EFSCORRUPTED;
+ xfs_alert(mp,
+"symlink header does not match required off/len/owner (0x%x/0x%x,0x%llx)",
+ offset, byte_cnt, ip->i_ino);
+ xfs_buf_relse(bp);
+ goto out;
+
+ }
+
+ cur_chunk += sizeof(struct xfs_dsymlink_hdr);
+ }
+
+ memcpy(link + offset, cur_chunk, byte_cnt);
+
+ pathlen -= byte_cnt;
+ offset += byte_cnt;
+
+ xfs_buf_relse(bp);
+ }
+ ASSERT(pathlen == 0);
+
+ link[ip->i_disk_size] = '\0';
+ error = 0;
+
+ out:
+ return error;
+}
diff --git a/libxfs/xfs_symlink_remote.h b/libxfs/xfs_symlink_remote.h
index c6f621a0ec0..bb83a8b8dfa 100644
--- a/libxfs/xfs_symlink_remote.h
+++ b/libxfs/xfs_symlink_remote.h
@@ -18,5 +18,6 @@ bool xfs_symlink_hdr_ok(xfs_ino_t ino, uint32_t offset,
void xfs_symlink_local_to_remote(struct xfs_trans *tp, struct xfs_buf *bp,
struct xfs_inode *ip, struct xfs_ifork *ifp);
xfs_failaddr_t xfs_symlink_shortform_verify(void *sfp, int64_t size);
+int xfs_symlink_remote_read(struct xfs_inode *ip, char *link);

#endif /* __XFS_SYMLINK_REMOTE_H */