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>

3 files changed, 41 insertions, 21 deletions

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 460aeb87c04e..374ba050942f 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -617,22 +617,27 @@ xfs_getbmap(
                 return XFS_ERROR(ENOMEM);
 
         xfs_ilock(ip, XFS_IOLOCK_SHARED);
-        if (whichfork == XFS_DATA_FORK && !(iflags & BMV_IF_DELALLOC)) {
-                if (ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_d.di_size) {
+        if (whichfork == XFS_DATA_FORK) {
+                if (!(iflags & BMV_IF_DELALLOC) &&
+                    (ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_d.di_size)) {
                         error = -filemap_write_and_wait(VFS_I(ip)->i_mapping);
                         if (error)
                                 goto out_unlock_iolock;
+
+                        /*
+                         * Even after flushing the inode, there can still be
+                         * delalloc blocks on the inode beyond EOF due to
+                         * speculative preallocation.  These are not removed
+                         * until the release function is called or the inode
+                         * is inactivated.  Hence we cannot assert here that
+                         * ip->i_delayed_blks == 0.
+                         */
                 }
-                /*
-                 * even after flushing the inode, there can still be delalloc
-                 * blocks on the inode beyond EOF due to speculative
-                 * preallocation. These are not removed until the release
-                 * function is called or the inode is inactivated. Hence we
-                 * cannot assert here that ip->i_delayed_blks == 0.
-                 */
-        }
 
-        lock = xfs_ilock_data_map_shared(ip);
+                lock = xfs_ilock_data_map_shared(ip);
+        } else {
+                lock = xfs_ilock_attr_map_shared(ip);
+        }
 
         /*
          * Don't let nex be bigger than the number of extents
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
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index fde368624ea7..65e2350f449c 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -338,6 +338,7 @@ void		xfs_iunlock(xfs_inode_t *, uint);
 void            xfs_ilock_demote(xfs_inode_t *, uint);
 int             xfs_isilocked(xfs_inode_t *, uint);
 uint            xfs_ilock_data_map_shared(struct xfs_inode *);
+uint            xfs_ilock_attr_map_shared(struct xfs_inode *);
 int             xfs_ialloc(struct xfs_trans *, xfs_inode_t *, umode_t,
                            xfs_nlink_t, xfs_dev_t, prid_t, int,
                            struct xfs_buf **, xfs_inode_t **);