f2fs: avoid race in between read xattr & write xattr
Thread A: Thread B:
-f2fs_getxattr
-lookup_all_xattrs
-xnid = F2FS_I(inode)->i_xattr_nid;
-f2fs_setxattr
-__f2fs_setxattr
-write_all_xattrs
-truncate_xattr_node
... ...
-write_checkpoint
... ...
-alloc_nid <- nid reuse
-get_node_page
-f2fs_bug_on <- nid != node_footer->nid
It's need a rw_sem to avoid the race
Signed-off-by: Yunlei He <heyunlei@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 96e1b7d..511bcec 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -630,6 +630,7 @@
init_rwsem(&fi->dio_rwsem[READ]);
init_rwsem(&fi->dio_rwsem[WRITE]);
init_rwsem(&fi->i_mmap_sem);
+ init_rwsem(&fi->i_xattr_sem);
#ifdef CONFIG_QUOTA
memset(&fi->i_dquot, 0, sizeof(fi->i_dquot));