Merge branch 'xfs-extent-list-locking-fixes' into for-next

A set of fixes which makes sure we are taking the ilock whenever accessing the
extent list.  This was associated with "Access to block zero" messages which
may result in extent list corruption.

1 files changed, 29 insertions, 33 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 833028cf205f..3a137e9f9a7d 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -77,48 +77,44 @@ xfs_get_extsz_hint(
 }
 
 /*
- * This is a wrapper routine around the xfs_ilock() routine used to centralize
- * some grungy code.  It is used in places that wish to lock the inode solely
- * for reading the extents.  The reason these places can't just call
- * xfs_ilock(SHARED) is that the inode lock also guards to bringing in of the
- * extents from disk for a file in b-tree format.  If the inode is in b-tree
- * format, then we need to lock the inode exclusively until the extents are read
- * in.  Locking it exclusively all the time would limit our parallelism
- * unnecessarily, though.  What we do instead is check to see if the extents
- * have been read in yet, and only lock the inode exclusively if they have not.
+ * These two are wrapper routines around the xfs_ilock() routine used to
+ * centralize some grungy code.  They are used in places that wish to lock the
+ * inode solely for reading the extents.  The reason these places can't just
+ * call xfs_ilock(ip, XFS_ILOCK_SHARED) is that the inode lock also guards to
+ * bringing in of the extents from disk for a file in b-tree format.  If the
+ * inode is in b-tree format, then we need to lock the inode exclusively until
+ * the extents are read in.  Locking it exclusively all the time would limit
+ * our parallelism unnecessarily, though.  What we do instead is check to see
+ * if the extents have been read in yet, and only lock the inode exclusively
+ * if they have not.
  *
- * The function returns a value which should be given to the corresponding
- * xfs_iunlock_map_shared().  This value is the mode in which the lock was
- * actually taken.
+ * The functions return a value which should be given to the corresponding
+ * xfs_iunlock() call.
  */
 uint
-xfs_ilock_map_shared(
-	xfs_inode_t	*ip)
+xfs_ilock_data_map_shared(
+	struct xfs_inode	*ip)
 {
-	uint	lock_mode;
+	uint			lock_mode = XFS_ILOCK_SHARED;
 
-	if ((ip->i_d.di_format == XFS_DINODE_FMT_BTREE) &&
-	    ((ip->i_df.if_flags & XFS_IFEXTENTS) == 0)) {
+	if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
+	    (ip->i_df.if_flags & XFS_IFEXTENTS) == 0)
 		lock_mode = XFS_ILOCK_EXCL;
-	} else {
-		lock_mode = XFS_ILOCK_SHARED;
-	}
-
 	xfs_ilock(ip, lock_mode);
-
 	return lock_mode;
 }
 
-/*
- * This is simply the unlock routine to go with xfs_ilock_map_shared().
- * All it does is call xfs_iunlock() with the given lock_mode.
- */
-void
-xfs_iunlock_map_shared(
-	xfs_inode_t	*ip,
-	unsigned int	lock_mode)
+uint
+xfs_ilock_attr_map_shared(
+	struct xfs_inode	*ip)
 {
-	xfs_iunlock(ip, lock_mode);
+	uint			lock_mode = XFS_ILOCK_SHARED;
+
+	if (ip->i_d.di_aformat == XFS_DINODE_FMT_BTREE &&
+	    (ip->i_afp->if_flags & XFS_IFEXTENTS) == 0)
+		lock_mode = XFS_ILOCK_EXCL;
+	xfs_ilock(ip, lock_mode);
+	return lock_mode;
 }
 
 /*
@@ -588,9 +584,9 @@ xfs_lookup(
 	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
 		return XFS_ERROR(EIO);
 
-	lock_mode = xfs_ilock_map_shared(dp);
+	lock_mode = xfs_ilock_data_map_shared(dp);
 	error = xfs_dir_lookup(NULL, dp, name, &inum, ci_name);
-	xfs_iunlock_map_shared(dp, lock_mode);
+	xfs_iunlock(dp, lock_mode);
 
 	if (error)
 		goto out;