From ead188f9f930fb5d7f0c49315a7fce3d8bd16b7e Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 8 Jun 2012 17:07:36 +0200 Subject: [PATCH] writeback: Fix lock imbalance in writeback_sb_inodes() Fix bug introduced by 169ebd90. We have to have wb_list_lock locked when restarting writeback loop after having waited for inode writeback. Bug description by Ted Tso: I can reproduce this fairly easily by using ext4 w/o a journal, running under KVM with 1024megs memory, with fsstress (xfstests #13): [ 45.153294] ===================================== [ 45.154784] [ BUG: bad unlock balance detected! ] [ 45.155591] 3.5.0-rc1-00002-gb22b1f1 #124 Not tainted [ 45.155591] ------------------------------------- [ 45.155591] flush-254:16/2499 is trying to release lock (&(&wb->list_lock)->rlock) at: [ 45.155591] [] writeback_sb_inodes+0x160/0x327 [ 45.155591] but there are no more locks to release! Reported-by: Theodore Ts'o Tested-by: Theodore Ts'o Signed-off-by: Jan Kara Signed-off-by: Fengguang Wu --- fs/fs-writeback.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 8d2fb8c88cf3..41a3ccff18d8 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -664,6 +664,7 @@ static long writeback_sb_inodes(struct super_block *sb, /* Wait for I_SYNC. This function drops i_lock... */ inode_sleep_on_writeback(inode); /* Inode may be gone, start again */ + spin_lock(&wb->list_lock); continue; } inode->i_state |= I_SYNC;