GFS2: Remember directory insert point

When we look to see if there is enough space to add a dir
entry without allocation, we have then been repeating the
same search later when we do the actual insertion. This
patch caches the details of the location in the gfs2_diradd
structure, so that we do not have to repeat the search.

This will provide a performance improvement which will be
greater as the size of the directory increases.

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

1 files changed, 23 insertions, 10 deletions

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 0b6be202a82c..d5988aafaa74 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -1659,26 +1659,34 @@ static int dir_new_leaf(struct inode *inode, const struct qstr *name)
 
 /**
  * gfs2_dir_add - Add new filename into directory
- * @dip: The GFS2 inode
- * @filename: The new name
- * @inode: The inode number of the entry
- * @type: The type of the entry
+ * @inode: The directory inode
+ * @name: The new name
+ * @nip: The GFS2 inode to be linked in to the directory
+ * @da: The directory addition info
+ *
+ * If the call to gfs2_diradd_alloc_required resulted in there being
+ * no need to allocate any new directory blocks, then it will contain
+ * a pointer to the directory entry and the bh in which it resides. We
+ * can use that without having to repeat the search. If there was no
+ * free space, then we must now create more space.
  *
  * Returns: 0 on success, error code on failure
  */
 
 int gfs2_dir_add(struct inode *inode, const struct qstr *name,
-                 const struct gfs2_inode *nip)
+                 const struct gfs2_inode *nip, struct gfs2_diradd *da)
 {
         struct gfs2_inode *ip = GFS2_I(inode);
-        struct buffer_head *bh;
-        struct gfs2_dirent *dent;
+        struct buffer_head *bh = da->bh;
+        struct gfs2_dirent *dent = da->dent;
         struct gfs2_leaf *leaf;
         int error;
 
         while(1) {
-                dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space,
-                                          &bh);
+                if (da->bh == NULL) {
+                        dent = gfs2_dirent_search(inode, name,
+                                                  gfs2_dirent_find_space, &bh);
+                }
                 if (dent) {
                         if (IS_ERR(dent))
                                 return PTR_ERR(dent);
@@ -1689,6 +1697,8 @@ int gfs2_dir_add(struct inode *inode, const struct qstr *name,
                                 leaf = (struct gfs2_leaf *)bh->b_data;
                                 be16_add_cpu(&leaf->lf_entries, 1);
                         }
+                        da->dent = NULL;
+                        da->bh = NULL;
                         brelse(bh);
                         ip->i_entries++;
                         ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
@@ -2030,6 +2040,8 @@ int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name,
         struct buffer_head *bh;
 
         da->nr_blocks = 0;
+        da->bh = NULL;
+        da->dent = NULL;
 
         dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);
         if (!dent) {
@@ -2038,7 +2050,8 @@ int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name,
         }
         if (IS_ERR(dent))
                 return PTR_ERR(dent);
-        brelse(bh);
+        da->bh = bh;
+        da->dent = dent;
         return 0;
 }