ext4: error proc entry creation when the fs/ext4 is not correctly created

When the directory fs/ext4 is not correctly created under proc, the entry
under this directory should not be created.

Signed-off-by: Shen Feng <shen@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 21ee6d4..771a1d6 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2661,6 +2661,10 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb)
        struct proc_dir_entry *proc;
        char devname[64];
 
+       if (proc_root_ext4 == NULL) {
+               sbi->s_mb_proc = NULL;
+               return -EINVAL;
+       }
        bdevname(sb->s_bdev, devname);
        sbi->s_mb_proc = proc_mkdir(devname, proc_root_ext4);