GFS2: Only do one directory search on create

Creation of a new inode requires a directory search in order to ensure
that we are not trying to create an inode with the same name as an
existing one. This was hidden away inside the create_ok() function.

In the case that there was an existing inode, and a lookup can be
substituted for a create (which is the case with regular files
when the O_EXCL flag is not in use) then we were doing a second
lookup in order to return the inode.

This patch merges these two lookups into one. This can be done by
passing a flag to gfs2_dir_search() to tell it to just return -EEXIST
in the cases where we don't actually want to look up the inode.

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

3 files changed, 25 insertions, 28 deletions

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index b631c9043460..f0c70529948f 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -1555,9 +1555,9 @@ out:
 
 /**
  * gfs2_dir_search - Search a directory
- * @dip: The GFS2 inode
- * @filename:
- * @inode:
+ * @dip: The GFS2 dir inode
+ * @name: The name we are looking up
+ * @fail_on_exist: Fail if the name exists rather than looking it up
  *
  * This routine searches a directory for a file or another directory.
  * Assumes a glock is held on dip.
@@ -1565,22 +1565,25 @@ out:
  * Returns: errno
  */
 
-struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name)
+struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name,
+                              bool fail_on_exist)
 {
         struct buffer_head *bh;
         struct gfs2_dirent *dent;
-        struct inode *inode;
+        u64 addr, formal_ino;
+        u16 dtype;
 
         dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
         if (dent) {
                 if (IS_ERR(dent))
                         return ERR_CAST(dent);
-                inode = gfs2_inode_lookup(dir->i_sb, 
-                                be16_to_cpu(dent->de_type),
-                                be64_to_cpu(dent->de_inum.no_addr),
-                                be64_to_cpu(dent->de_inum.no_formal_ino), 0);
+                dtype = be16_to_cpu(dent->de_type);
+                addr = be64_to_cpu(dent->de_inum.no_addr);
+                formal_ino = be64_to_cpu(dent->de_inum.no_formal_ino);
                 brelse(bh);
-                return inode;
+                if (fail_on_exist)
+                        return ERR_PTR(-EEXIST);
+                return gfs2_inode_lookup(dir->i_sb, dtype, addr, formal_ino, 0);
         }
         return ERR_PTR(-ENOENT);
 }
diff --git a/fs/gfs2/dir.h b/fs/gfs2/dir.h
index 98c960beab35..d3f273870b49 100644
--- a/fs/gfs2/dir.h
+++ b/fs/gfs2/dir.h
@@ -18,7 +18,8 @@ struct gfs2_inode;
 struct gfs2_inum;
 
 extern struct inode *gfs2_dir_search(struct inode *dir,
-                                     const struct qstr *filename);
+                                     const struct qstr *filename,
+                                     bool fail_on_exist);
 extern int gfs2_dir_check(struct inode *dir, const struct qstr *filename,
                           const struct gfs2_inode *ip);
 extern int gfs2_dir_add(struct inode *inode, const struct qstr *filename,
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 5fbb8dfb4653..ede16ae784e2 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -313,7 +313,7 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
                         goto out;
         }
 
-        inode = gfs2_dir_search(dir, name);
+        inode = gfs2_dir_search(dir, name, false);
         if (IS_ERR(inode))
                 error = PTR_ERR(inode);
 out:
@@ -346,17 +346,6 @@ static int create_ok(struct gfs2_inode *dip, const struct qstr *name,
         if (!dip->i_inode.i_nlink)
                 return -ENOENT;
 
-        error = gfs2_dir_check(&dip->i_inode, name, NULL);
-        switch (error) {
-        case -ENOENT:
-                error = 0;
-                break;
-        case 0:
-                return -EEXIST;
-        default:
-                return error;
-        }
-
         if (dip->i_entries == (u32)-1)
                 return -EFBIG;
         if (S_ISDIR(mode) && dip->i_inode.i_nlink == (u32)-1)
@@ -584,14 +573,18 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
                 goto fail;
 
         error = create_ok(dip, name, mode);
-        if ((error == -EEXIST) && S_ISREG(mode) && !excl) {
-                inode = gfs2_lookupi(dir, &dentry->d_name, 0);
+        if (error)
+                goto fail_gunlock;
+
+        inode = gfs2_dir_search(dir, &dentry->d_name, !S_ISREG(mode) || excl);
+        error = PTR_ERR(inode);
+        if (!IS_ERR(inode)) {
                 gfs2_glock_dq_uninit(ghs);
                 d_instantiate(dentry, inode);
-                return PTR_RET(inode);
-        }
-        if (error)
+                return 0;
+        } else if (error != -ENOENT) {
                 goto fail_gunlock;
+        }
 
         arq = error = gfs2_diradd_alloc_required(dir, name);
         if (error < 0)