ocfs2: Implement ocfs2_empty_dir() as a caller of ocfs2_dir_foreach()

We can preserve the behavior of ocfs2_empty_dir(), while getting rid of the
open coded directory walk by just providing a smart filldir callback. This
also automatically gets to use the dir readahead code, though in this case
any advantage is minor at best.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Reviewed-by: Joel Becker <joel.becker@oracle.com>

2 files changed, 46 insertions, 52 deletions

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index a75c340fc689..4bb54406354b 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -660,67 +660,61 @@ bail:
         return ret;
 }
 
+struct ocfs2_empty_dir_priv {
+        unsigned seen_dot;
+        unsigned seen_dot_dot;
+        unsigned seen_other;
+};
+static int ocfs2_empty_dir_filldir(void *priv, const char *name, int name_len,
+                                   loff_t pos, u64 ino, unsigned type)
+{
+        struct ocfs2_empty_dir_priv *p = priv;
+
+        /*
+         * Check the positions of "." and ".." records to be sure
+         * they're in the correct place.
+         */
+        if (name_len == 1 && !strncmp(".", name, 1) && pos == 0) {
+                p->seen_dot = 1;
+                return 0;
+        }
+
+        if (name_len == 2 && !strncmp("..", name, 2) &&
+            pos == OCFS2_DIR_REC_LEN(1)) {
+                p->seen_dot_dot = 1;
+                return 0;
+        }
+
+        p->seen_other = 1;
+        return 1;
+}
 /*
  * routine to check that the specified directory is empty (for rmdir)
+ *
+ * Returns 1 if dir is empty, zero otherwise.
  */
 int ocfs2_empty_dir(struct inode *inode)
 {
-        unsigned long offset;
-        struct buffer_head * bh;
-        struct ocfs2_dir_entry * de, * de1;
-        struct super_block * sb;
-        int err;
+        int ret;
+        loff_t start = 0;
+        struct ocfs2_empty_dir_priv priv;
 
-        sb = inode->i_sb;
-        if ((i_size_read(inode) <
-             (OCFS2_DIR_REC_LEN(1) + OCFS2_DIR_REC_LEN(2))) ||
-            !(bh = ocfs2_bread(inode, 0, &err, 0))) {
-                mlog(ML_ERROR, "bad directory (dir #%llu) - no data block\n",
-                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
-                return 1;
-        }
+        memset(&priv, 0, sizeof(priv));
 
-        de = (struct ocfs2_dir_entry *) bh->b_data;
-        de1 = (struct ocfs2_dir_entry *)
-                        ((char *)de + le16_to_cpu(de->rec_len));
-        if ((le64_to_cpu(de->inode) != OCFS2_I(inode)->ip_blkno) ||
-                        !le64_to_cpu(de1->inode) ||
-                        strcmp(".", de->name) ||
-                        strcmp("..", de1->name)) {
-                mlog(ML_ERROR, "bad directory (dir #%llu) - no `.' or `..'\n",
+        ret = ocfs2_dir_foreach(inode, &start, &priv, ocfs2_empty_dir_filldir);
+        if (ret)
+                mlog_errno(ret);
+
+        if (!priv.seen_dot || !priv.seen_dot_dot) {
+                mlog(ML_ERROR, "bad directory (dir #%llu) - no `.' or `..'\n",
                      (unsigned long long)OCFS2_I(inode)->ip_blkno);
-                brelse(bh);
+                /*
+                 * XXX: Is it really safe to allow an unlink to continue?
+                 */
                 return 1;
         }
-        offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
-        de = (struct ocfs2_dir_entry *)((char *)de1 + le16_to_cpu(de1->rec_len));
-        while (offset < i_size_read(inode) ) {
-                if (!bh || (void *)de >= (void *)(bh->b_data + sb->s_blocksize)) {
-                        brelse(bh);
-                        bh = ocfs2_bread(inode,
-                                         offset >> sb->s_blocksize_bits, &err, 0);
-                        if (!bh) {
-                                mlog(ML_ERROR, "dir %llu has a hole at %lu\n",
-                                     (unsigned long long)OCFS2_I(inode)->ip_blkno, offset);
-                                offset += sb->s_blocksize;
-                                continue;
-                        }
-                        de = (struct ocfs2_dir_entry *) bh->b_data;
-                }
-                if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
-                        brelse(bh);
-                        return 1;
-                }
-                if (le64_to_cpu(de->inode)) {
-                        brelse(bh);
-                        return 0;
-                }
-                offset += le16_to_cpu(de->rec_len);
-                de = (struct ocfs2_dir_entry *)
-                        ((char *)de + le16_to_cpu(de->rec_len));
-        }
-        brelse(bh);
-        return 1;
+
+        return !priv.seen_other;
 }
 
 int ocfs2_fill_new_dir(struct ocfs2_super *osb,
diff --git a/fs/ocfs2/dir.h b/fs/ocfs2/dir.h
index 075d0e9fd459..3e65f91b034d 100644
--- a/fs/ocfs2/dir.h
+++ b/fs/ocfs2/dir.h
@@ -54,7 +54,7 @@ static inline int ocfs2_add_entry(handle_t *handle,
 int ocfs2_check_dir_for_entry(struct inode *dir,
                               const char *name,
                               int namelen);
-int ocfs2_empty_dir(struct inode *inode);  /* FIXME: to namei.c */
+int ocfs2_empty_dir(struct inode *inode);
 int ocfs2_find_files_on_disk(const char *name,
                              int namelen,
                              u64 *blkno,