From 2b405bfa84063bfa35621d2d6879f52693c614b0 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 20 Mar 2013 09:42:11 -0400 Subject: [PATCH] ext4: fix data=journal fast mount/umount hang In data=journal mode, if we unmount the file system before a transaction has a chance to complete, when the journal inode is being evicted, we can end up calling into jbd2_log_wait_commit() for the last transaction, after the journalling machinery has been shut down. Arguably we should adjust ext4_should_journal_data() to return FALSE for the journal inode, but the only place it matters is ext4_evict_inode(), and so to save a bit of CPU time, and to make the patch much more obviously correct by inspection(tm), we'll fix it by explicitly not trying to waiting for a journal commit when we are evicting the journal inode, since it's guaranteed to never succeed in this case. This can be easily replicated via: mount -t ext4 -o data=journal /dev/vdb /vdb ; umount /vdb ------------[ cut here ]------------ WARNING: at /usr/projects/linux/ext4/fs/jbd2/journal.c:542 __jbd2_log_start_commit+0xba/0xcd() Hardware name: Bochs JBD2: bad log_start_commit: 3005630206 3005630206 0 0 Modules linked in: Pid: 2909, comm: umount Not tainted 3.8.0-rc3 #1020 Call Trace: [] warn_slowpath_common+0x68/0x7d [] ? __jbd2_log_start_commit+0xba/0xcd [] warn_slowpath_fmt+0x2b/0x2f [] __jbd2_log_start_commit+0xba/0xcd [] jbd2_log_start_commit+0x24/0x34 [] ext4_evict_inode+0x71/0x2e3 [] evict+0x94/0x135 [] iput+0x10a/0x110 [] jbd2_journal_destroy+0x190/0x1ce [] ? bit_waitqueue+0x50/0x50 [] ext4_put_super+0x52/0x294 [] generic_shutdown_super+0x48/0xb4 [] kill_block_super+0x22/0x60 [] deactivate_locked_super+0x22/0x49 [] deactivate_super+0x30/0x33 [] mntput_no_expire+0x107/0x10c [] sys_umount+0x2cf/0x2e0 [] sys_oldumount+0x12/0x14 [] syscall_call+0x7/0xb ---[ end trace 6a954cc790501c1f ]--- jbd2_log_wait_commit: error: j_commit_request=-1289337090, tid=0 Signed-off-by: "Theodore Ts'o" Reviewed-by: Jan Kara Cc: stable@vger.kernel.org --- fs/ext4/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index ea5f24ffa60c..85e41a2a39ad 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -205,7 +205,8 @@ void ext4_evict_inode(struct inode *inode) * don't use page cache. */ if (ext4_should_journal_data(inode) && - (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) { + (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) && + inode->i_ino != EXT4_JOURNAL_INO) { journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;