xfs: add xfs_ilock_attr_map_shared

Equivalent to xfs_ilock_data_map_shared, except for the attribute fork.

Make xfs_getbmap use it if called for the attribute fork instead of
xfs_ilock_data_map_shared.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 24 insertions, 10 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index fdd483783365..e655bb07e8bb 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -77,17 +77,18 @@ 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
+ * The functions return a value which should be given to the corresponding
  * xfs_iunlock() call.
  */
 uint
@@ -103,6 +104,19 @@ xfs_ilock_data_map_shared(
         return lock_mode;
 }
 
+uint
+xfs_ilock_attr_map_shared(
+        struct xfs_inode        *ip)
+{
+        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;
+}
+
 /*
  * The xfs inode contains 2 locks: a multi-reader lock called the
  * i_iolock and a multi-reader lock called the i_lock.  This routine