[PATCH v4] xfs: fix the symbolic link assert in xfs_ifree

[Mark Tinguely <tinguely@sgi.com>]

a
Content-Disposition: inline; filename=v4-xfs-fix-assert-in-xfs_ifree.patch

Adding an extended attribute to a symbolic link can force that
link to an remote extent. xfs_inactive() incorrectly assumes
that any symbolic link small enough to be in the inode core
is incore, resulting in the remote extent to not be removed.
xfs_ifree() will assert on presence of this leaked remote extent.

Signed-off-by: Mark Tinguely <tinguely@sgi.com>
---
 v4:
   changed pathlen to int.
   print inode in hex
   fixed the trace to be xfs_inactive_symlink in source and trace code.

 fs/xfs/xfs_symlink.c  |   48 ++++++++++++++++++++++++++++++++++++++++++++++--
 fs/xfs/xfs_symlink.h  |    2 +-
 fs/xfs/xfs_trace.h    |    1 +
 fs/xfs/xfs_vnodeops.c |   15 +++------------
 4 files changed, 51 insertions(+), 15 deletions(-)

Index: b/fs/xfs/xfs_symlink.c
===================================================================
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -585,7 +585,7 @@ xfs_symlink(
 /*
  * Free a symlink that has blocks associated with it.
  */
-int
+STATIC int
 xfs_inactive_symlink_rmt(
 	xfs_inode_t	*ip,
 	xfs_trans_t	**tpp)
@@ -606,7 +606,7 @@ xfs_inactive_symlink_rmt(
 
 	tp = *tpp;
 	mp = ip->i_mount;
-	ASSERT(ip->i_d.di_size > XFS_IFORK_DSIZE(ip));
+	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
 	/*
 	 * We're freeing a symlink that has some
 	 * blocks allocated to it.  Free the
@@ -720,3 +720,47 @@ xfs_inactive_symlink_rmt(
  error0:
 	return error;
 }
+
+/*
+ * xfs_inactive_symlink - free a symlink
+ */
+int
+xfs_inactive_symlink(
+	struct xfs_inode	*ip,
+	struct xfs_trans	**tp)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	int			pathlen;
+
+	trace_xfs_inactive_symlink(ip);
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+	if (XFS_FORCED_SHUTDOWN(mp))
+		return XFS_ERROR(EIO);
+
+	/*
+	 * Zero length symlinks _can_ exist.
+	 */
+	pathlen = (int)ip->i_d.di_size;
+	if (!pathlen)
+		return 0;
+
+	if (pathlen < 0 || pathlen > MAXPATHLEN) {
+		xfs_alert(mp, "%s: inode (%llx) bad symlink length (%d)",
+			 __func__, (unsigned long long)ip->i_ino, pathlen);
+		ASSERT(0);
+		return XFS_ERROR(EFSCORRUPTED);
+	}
+
+	if (ip->i_df.if_flags & XFS_IFINLINE) {
+		if (ip->i_df.if_bytes > 0)
+			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
+					  XFS_DATA_FORK);
+		ASSERT(ip->i_df.if_bytes == 0);
+		return 0;
+	}
+
+	/* remove the remote symlink */
+	return xfs_inactive_symlink_rmt(ip, tp);
+}
Index: b/fs/xfs/xfs_symlink.h
===================================================================
--- a/fs/xfs/xfs_symlink.h
+++ b/fs/xfs/xfs_symlink.h
@@ -60,7 +60,7 @@ extern const struct xfs_buf_ops xfs_syml
 int xfs_symlink(struct xfs_inode *dp, struct xfs_name *link_name,
 		const char *target_path, umode_t mode, struct xfs_inode **ipp);
 int xfs_readlink(struct xfs_inode *ip, char *link);
-int xfs_inactive_symlink_rmt(struct xfs_inode *ip, struct xfs_trans **tpp);
+int xfs_inactive_symlink(struct xfs_inode *ip, struct xfs_trans **tpp);
 
 #endif /* __KERNEL__ */
 #endif /* __XFS_SYMLINK_H */
Index: b/fs/xfs/xfs_trace.h
===================================================================
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -571,6 +571,7 @@ DEFINE_INODE_EVENT(xfs_iget_miss);
 DEFINE_INODE_EVENT(xfs_getattr);
 DEFINE_INODE_EVENT(xfs_setattr);
 DEFINE_INODE_EVENT(xfs_readlink);
+DEFINE_INODE_EVENT(xfs_inactive_symlink);
 DEFINE_INODE_EVENT(xfs_alloc_file_space);
 DEFINE_INODE_EVENT(xfs_free_file_space);
 DEFINE_INODE_EVENT(xfs_readdir);
Index: b/fs/xfs/xfs_vnodeops.c
===================================================================
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -322,18 +322,9 @@ xfs_inactive(
 	xfs_trans_ijoin(tp, ip, 0);
 
 	if (S_ISLNK(ip->i_d.di_mode)) {
-		/*
-		 * Zero length symlinks _can_ exist.
-		 */
-		if (ip->i_d.di_size > XFS_IFORK_DSIZE(ip)) {
-			error = xfs_inactive_symlink_rmt(ip, &tp);
-			if (error)
-				goto out_cancel;
-		} else if (ip->i_df.if_bytes > 0) {
-			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
-					  XFS_DATA_FORK);
-			ASSERT(ip->i_df.if_bytes == 0);
-		}
+		error = xfs_inactive_symlink(ip, &tp);
+		if (error)
+			goto out_cancel;
 	} else if (truncate) {
 		ip->i_d.di_size = 0;
 		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);


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