From 27161f13e3c3241944846ac24942a85cceda0a2c Mon Sep 17 00:00:00 2001 From: Yunlei He Date: Thu, 7 Sep 2017 10:40:54 +0800 Subject: 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 Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/xattr.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/f2fs/xattr.c') diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index ef3a3721ea6b..7c65540148f8 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -473,8 +473,10 @@ int f2fs_getxattr(struct inode *inode, int index, const char *name, if (len > F2FS_NAME_LEN) return -ERANGE; + down_read(&F2FS_I(inode)->i_xattr_sem); error = lookup_all_xattrs(inode, ipage, index, len, name, &entry, &base_addr); + up_read(&F2FS_I(inode)->i_xattr_sem); if (error) return error; @@ -503,7 +505,9 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) int error = 0; size_t rest = buffer_size; + down_read(&F2FS_I(inode)->i_xattr_sem); error = read_all_xattrs(inode, NULL, &base_addr); + up_read(&F2FS_I(inode)->i_xattr_sem); if (error) return error; @@ -686,7 +690,9 @@ int f2fs_setxattr(struct inode *inode, int index, const char *name, f2fs_lock_op(sbi); /* protect xattr_ver */ down_write(&F2FS_I(inode)->i_sem); + down_write(&F2FS_I(inode)->i_xattr_sem); err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags); + up_write(&F2FS_I(inode)->i_xattr_sem); up_write(&F2FS_I(inode)->i_sem); f2fs_unlock_op(sbi); -- cgit v1.2.3