GFS2: Add directory addition info structure

The intent is that this structure will hold the information
required when adding entries to a directory (linking). To
start with, it will contain only the number of blocks which
are required to link the new entry into the directory. The
current calculation returns either 0 or the maximim number of
blocks that can ever be requested by such a transaction.

The intent is that in a later patch, we can update the dir
code to calculate this value more accurately. In addition
further patches will also add further fields to the new
structure to increase its utility.

In addition this patch fixes a bug where the link used during
inode creation was adding requesting too many blocks in
some cases. This is harmless unless the fs is close to being
full.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 2e5fc268d324..0b6be202a82c 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -2017,18 +2017,24 @@ out:
  * gfs2_diradd_alloc_required - find if adding entry will require an allocation
  * @ip: the file being written to
  * @filname: the filename that's going to be added
+ * @da: The structure to return dir alloc info
  *
- * Returns: 1 if alloc required, 0 if not, -ve on error
+ * Returns: 0 if ok, -ve on error
  */
 
-int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name)
+int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name,
+                               struct gfs2_diradd *da)
 {
+        struct gfs2_sbd *sdp = GFS2_SB(inode);
         struct gfs2_dirent *dent;
         struct buffer_head *bh;
 
+        da->nr_blocks = 0;
+
         dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);
         if (!dent) {
-                return 1;
+                da->nr_blocks = sdp->sd_max_dirres;
+                return 0;
         }
         if (IS_ERR(dent))
                 return PTR_ERR(dent);