f2fs: make posix_acl_create() safer and cleaner

Our f2fs_acl_create is copied from posix_acl_create in ./fs/posix_acl.c and
modified to avoid deadlock bug when inline_dentry feature is enabled.

Dan Carpenter rewrites posix_acl_create in commit 2799563b281f
("fs/posix_acl.c: make posix_acl_create() safer and cleaner") to make this
function more safer, so that we can avoid potential bug in its caller,
especially for ocfs2.

Let's back port the patch to f2fs.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index 4320ffab3495bbadb6c9b176e98241904bc51ecb..c8f25f7241f06a96c3d99ebf5c82e53a6099ed60 100644 (file)
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -334,51 +334,45 @@ static int f2fs_acl_create(struct inode *dir, umode_t *mode,
                struct page *dpage)
 {
        struct posix_acl *p;
+       struct posix_acl *clone;
        int ret;
 
+       *acl = NULL;
+       *default_acl = NULL;
+
        if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
-               goto no_acl;
+               return 0;
 
        p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
-       if (IS_ERR(p)) {
-               if (p == ERR_PTR(-EOPNOTSUPP))
-                       goto apply_umask;
-               return PTR_ERR(p);
+       if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
+               *mode &= ~current_umask();
+               return 0;
        }
+       if (IS_ERR(p))
+               return PTR_ERR(p);
 
-       if (!p)
-               goto apply_umask;
-
-       *acl = f2fs_acl_clone(p, GFP_NOFS);
-       if (!*acl)
+       clone = f2fs_acl_clone(p, GFP_NOFS);
+       if (!clone)
                goto no_mem;
 
-       ret = f2fs_acl_create_masq(*acl, mode);
+       ret = f2fs_acl_create_masq(clone, mode);
        if (ret < 0)
                goto no_mem_clone;
 
-       if (ret == 0) {
-               posix_acl_release(*acl);
-               *acl = NULL;
-       }
+       if (ret == 0)
+               posix_acl_release(clone);
+       else
+               *acl = clone;
 
-       if (!S_ISDIR(*mode)) {
+       if (!S_ISDIR(*mode))
                posix_acl_release(p);
-               *default_acl = NULL;
-       } else {
+       else
                *default_acl = p;
-       }
-       return 0;
 
-apply_umask:
-       *mode &= ~current_umask();
-no_acl:
-       *default_acl = NULL;
-       *acl = NULL;
        return 0;
 
 no_mem_clone:
-       posix_acl_release(*acl);
+       posix_acl_release(clone);
 no_mem:
        posix_acl_release(p);
        return -ENOMEM;