ubifs: Set/Clear I_LINKABLE under i_lock for whiteout inode
xfstests-generic/476 reports a warning message as below:
WARNING: CPU: 2 PID: 30347 at fs/inode.c:361 inc_nlink+0x52/0x70
Call Trace:
do_rename+0x502/0xd40 [ubifs]
ubifs_rename+0x8b/0x180 [ubifs]
vfs_rename+0x476/0x1080
do_renameat2+0x67c/0x7b0
__x64_sys_renameat2+0x6e/0x90
do_syscall_64+0x66/0xe0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Following race case can cause this:
rename_whiteout(Thread 1) wb_workfn(Thread 2)
ubifs_rename
do_rename
__writeback_single_inode
spin_lock(&inode->i_lock)
whiteout->i_state |= I_LINKABLE
inode->i_state &= ~dirty;
---- How race happens on i_state:
(tmp = whiteout->i_state | I_LINKABLE)
(tmp = inode->i_state & ~dirty)
(whiteout->i_state = tmp)
(inode->i_state = tmp)
----
spin_unlock(&inode->i_lock)
inc_nlink(whiteout)
WARN_ON(!(inode->i_state & I_LINKABLE)) !!!
Fix to add i_lock to avoid i_state update race condition.
Fixes: 9e0a1fff8db56ea ("ubifs: Implement RENAME_WHITEOUT")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
1 file changed
