[PATCH] libxfs: rename MAXPATHLEN to XFS_SYMLINK_MAXLEN

["Darrick J. Wong" <darrick.wong@oracle.com>]

XFS has a maximum symlink target length of 1024 bytes; this is a
holdover from the Irix days.  Unfortunately, the constant establishing
this was 'MAXPATHLEN', and is /not/ the same as the Linux MAXPATHLEN,
which is 4096.

The kernel enforces its 1024 byte MAXPATHLEN on symlink targets, but
xfsprogs picks up the (Linux) system 4096 byte MAXPATHLEN, which means
that xfs_repair doesn't complain about oversized symlinks.

Since this is an on-disk format constraint, put the define in the XFS
namespace.  As a side effect of the rename, xfs_repair wil detect
oversized symlinks and clean them off the system.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 libxfs/xfs_format.h         |    1 +
 libxfs/xfs_symlink_remote.c |    2 +-
 libxfs/xfs_trans_resv.c     |    4 ++--
 repair/dinode.c             |    6 +++---
 repair/xfs_repair.c         |    2 +-
 5 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
index a53f035..79a72bb 100644
--- a/libxfs/xfs_format.h
+++ b/libxfs/xfs_format.h
@@ -1211,6 +1211,7 @@ struct xfs_dsymlink_hdr {
 
 #define XFS_SYMLINK_CRC_OFF	offsetof(struct xfs_dsymlink_hdr, sl_crc)
 
+#define XFS_SYMLINK_MAXLEN	1024
 /*
  * The maximum pathlen is 1024 bytes. Since the minimum file system
  * blocksize is 512 bytes, we can get a max of 3 extents back from
diff --git a/libxfs/xfs_symlink_remote.c b/libxfs/xfs_symlink_remote.c
index 04c7446..d638530 100644
--- a/libxfs/xfs_symlink_remote.c
+++ b/libxfs/xfs_symlink_remote.c
@@ -110,7 +110,7 @@ xfs_symlink_verify(
 	if (bp->b_bn != be64_to_cpu(dsl->sl_blkno))
 		return false;
 	if (be32_to_cpu(dsl->sl_offset) +
-				be32_to_cpu(dsl->sl_bytes) >= MAXPATHLEN)
+				be32_to_cpu(dsl->sl_bytes) >= XFS_SYMLINK_MAXLEN)
 		return false;
 	if (dsl->sl_owner == 0)
 		return false;
diff --git a/libxfs/xfs_trans_resv.c b/libxfs/xfs_trans_resv.c
index 5152a5b..d35a45f 100644
--- a/libxfs/xfs_trans_resv.c
+++ b/libxfs/xfs_trans_resv.c
@@ -476,14 +476,14 @@ xfs_calc_mkdir_reservation(
 /*
  * Making a new symplink is the same as creating a new file, but
  * with the added blocks for remote symlink data which can be up to 1kB in
- * length (MAXPATHLEN).
+ * length (XFS_SYMLINK_MAXLEN).
  */
 STATIC uint
 xfs_calc_symlink_reservation(
 	struct xfs_mount	*mp)
 {
 	return xfs_calc_create_reservation(mp) +
-	       xfs_calc_buf_res(1, MAXPATHLEN);
+	       xfs_calc_buf_res(1, XFS_SYMLINK_MAXLEN);
 }
 
 /*
diff --git a/repair/dinode.c b/repair/dinode.c
index da87217..f005335 100644
--- a/repair/dinode.c
+++ b/repair/dinode.c
@@ -1259,7 +1259,7 @@ null_check(char *name, int length)
 {
 	int i;
 
-	ASSERT(length < MAXPATHLEN);
+	ASSERT(length < XFS_SYMLINK_MAXLEN);
 
 	for (i = 0; i < length; i++, name++)  {
 		if (*name == '\0')
@@ -1371,7 +1371,7 @@ process_symlink(
 	blkmap_t 	*blkmap)
 {
 	char			*symlink;
-	char			data[MAXPATHLEN];
+	char			data[XFS_SYMLINK_MAXLEN];
 
 	/*
 	 * check size against kernel symlink limits.  we know
@@ -1379,7 +1379,7 @@ process_symlink(
 	 * the inode is structurally ok so we don't have to check
 	 * for that
 	 */
-	if (be64_to_cpu(dino->di_size) >= MAXPATHLEN)  {
+	if (be64_to_cpu(dino->di_size) >= XFS_SYMLINK_MAXLEN)  {
 	       do_warn(_("symlink in inode %" PRIu64 " too long (%llu chars)\n"),
 		       lino, (unsigned long long) be64_to_cpu(dino->di_size));
 		return(1);
diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c
index ab60c0f..b2dd91b 100644
--- a/repair/xfs_repair.c
+++ b/repair/xfs_repair.c
@@ -761,7 +761,7 @@ main(int argc, char **argv)
 	glob_agcount = mp->m_sb.sb_agcount;
 
 	chunks_pblock = mp->m_sb.sb_inopblock / XFS_INODES_PER_CHUNK;
-	max_symlink_blocks = libxfs_symlink_blocks(mp, MAXPATHLEN);
+	max_symlink_blocks = libxfs_symlink_blocks(mp, XFS_SYMLINK_MAXLEN);
 	inodes_per_cluster = MAX(mp->m_sb.sb_inopblock,
 			mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog);