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>

1 files changed, 20 insertions, 26 deletions

diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index 4320ffab3495..c8f25f7241f0 100644
--- 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;