Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux

[~andy/linux] / fs / xfs / xfs_bmap_btree.c

diff --git a/fs/xfs/xfs_bmap_btree.c b/fs/xfs/xfs_bmap_btree.c
index cf3bc76710c3de6e021b37ccc275894458f8c931..bb8de8e399c4b351effa08e6669e000438751d37 100644 (file)
--- a/fs/xfs/xfs_bmap_btree.c
+++ b/fs/xfs/xfs_bmap_btree.c
@@ -925,3 +925,47 @@ xfs_bmdr_maxrecs(
                return blocklen / sizeof(xfs_bmdr_rec_t);
        return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
 }
+
+/*
+ * Change the owner of a btree format fork fo the inode passed in. Change it to
+ * the owner of that is passed in so that we can change owners before or after
+ * we switch forks between inodes. The operation that the caller is doing will
+ * determine whether is needs to change owner before or after the switch.
+ *
+ * For demand paged transactional modification, the fork switch should be done
+ * after reading in all the blocks, modifying them and pinning them in the
+ * transaction. For modification when the buffers are already pinned in memory,
+ * the fork switch can be done before changing the owner as we won't need to
+ * validate the owner until the btree buffers are unpinned and writes can occur
+ * again.
+ *
+ * For recovery based ownership change, there is no transactional context and
+ * so a buffer list must be supplied so that we can record the buffers that we
+ * modified for the caller to issue IO on.
+ */
+int
+xfs_bmbt_change_owner(
+       struct xfs_trans        *tp,
+       struct xfs_inode        *ip,
+       int                     whichfork,
+       xfs_ino_t               new_owner,
+       struct list_head        *buffer_list)
+{
+       struct xfs_btree_cur    *cur;
+       int                     error;
+
+       ASSERT(tp || buffer_list);
+       ASSERT(!(tp && buffer_list));
+       if (whichfork == XFS_DATA_FORK)
+               ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_BTREE);
+       else
+               ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_BTREE);
+
+       cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
+       if (!cur)
+               return ENOMEM;
+
+       error = xfs_btree_change_owner(cur, new_owner, buffer_list);
+       xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
+       return error;
+}