VFS uses f2fs_lookup() to decide f2fs_add_link() call during file creation.
But, if there is a race condition, f2fs_add_link() can be called multiple
times, resulting in multiple dentries with a same name. This patches fixes
it by adding __f2fs_find_entry() in f2fs_add_link() path.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/dir.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 827c5daef4fc..bc7c48839bec 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -643,14 +643,24 @@ int __f2fs_add_link(struct inode *dir, const struct qstr *name,
struct inode *inode, nid_t ino, umode_t mode)
{
struct fscrypt_name fname;
+ struct page *page;
+ struct f2fs_dir_entry *de;
int err;
err = fscrypt_setup_filename(dir, name, 0, &fname);
if (err)
return err;
- err = __f2fs_do_add_link(dir, &fname, inode, ino, mode);
-
+ de = __f2fs_find_entry(dir, &fname, &page);
+ if (de) {
+ f2fs_dentry_kunmap(dir, page);
+ f2fs_put_page(page, 0);
+ err = -EEXIST;
+ } else if (!IS_ERR(page)) {
+ err = __f2fs_do_add_link(dir, &fname, inode, ino, mode);
+ } else {
+ err = PTR_ERR(page);
+ }
fscrypt_free_filename(&fname);
return err;
}
--
2.11.0
