ocfs2: roll back the reference count modification of the parent directory if an error occurs

Under some conditions, the directory cannot be deleted.  The specific
scenarios are as follows: (for example, /mnt/ocfs2 is the mount point)

1. Create the /mnt/ocfs2/p_dir directory.  At this time, the i_nlink
   corresponding to the inode of the /mnt/ocfs2/p_dir directory is equal
   to 2.

2. During the process of creating the /mnt/ocfs2/p_dir/s_dir
   directory, if the call to the inc_nlink function in ocfs2_mknod
   succeeds, the functions such as ocfs2_init_acl,
   ocfs2_init_security_set, and ocfs2_dentry_attach_lock fail.  At this
   time, the i_nlink corresponding to the inode of the /mnt/ocfs2/p_dir
   directory is equal to 3, but /mnt/ocfs2/p_dir/s_dir is not added to the
   /mnt/ocfs2/p_dir directory entry.

3. Delete the /mnt/ocfs2/p_dir directory (rm -rf /mnt/ocfs2/p_dir).
   At this time, it is found that the i_nlink corresponding to the inode
   corresponding to the /mnt/ocfs2/p_dir directory is equal to 3.
   Therefore, the /mnt/ocfs2/p_dir directory cannot be deleted.
Signed-off-by: Jian wang <wangjian161@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Link: http://lkml.kernel.org/r/a44f6666-bbc4-405e-0e6c-0f4e922eeef6@huawei.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/namei.c

@@ -406,7 +406,7 @@ static int ocfs2_mknod(struct inode *dir,
 
 	if (status < 0) {
 		mlog_errno(status);
-		goto leave;
+		goto roll_back;
 	}
 
 	if (si.enable) {
@@ -414,7 +414,7 @@ static int ocfs2_mknod(struct inode *dir,
 						 meta_ac, data_ac);
 		if (status < 0) {
 			mlog_errno(status);
-			goto leave;
+			goto roll_back;
 		}
 	}
 
@@ -427,7 +427,7 @@ static int ocfs2_mknod(struct inode *dir,
 					  OCFS2_I(dir)->ip_blkno);
 	if (status) {
 		mlog_errno(status);
-		goto leave;
+		goto roll_back;
 	}
 
 	dl = dentry->d_fsdata;
@@ -437,12 +437,19 @@ static int ocfs2_mknod(struct inode *dir,
 				 &lookup);
 	if (status < 0) {
 		mlog_errno(status);
-		goto leave;
+		goto roll_back;
 	}
 
 	insert_inode_hash(inode);
 	d_instantiate(dentry, inode);
 	status = 0;
+
+roll_back:
+	if (status < 0 && S_ISDIR(mode)) {
+		ocfs2_add_links_count(dirfe, -1);
+		drop_nlink(dir);
+	}
+
 leave:
 	if (status < 0 && did_quota_inode)
 		dquot_free_inode(inode);