From 0523676d3f3aa7edeea63cc3a1bc4dc612380a26 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 30 Dec 2009 05:56:08 +0100 Subject: [PATCH] reiserfs: Relax reiserfs lock while freeing the journal Keeping the reiserfs lock while freeing the journal on umount path triggers a lock inversion between bdev->bd_mutex and the reiserfs lock. We don't need the reiserfs lock at this stage. The filesystem is not usable anymore, and there are no more pending commits, everything got flushed (even this operation was done in parallel and didn't required the reiserfs lock from the current process). This fixes the following lockdep report: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.32-atom #172 ------------------------------------------------------- umount/3904 is trying to acquire lock: (&bdev->bd_mutex){+.+.+.}, at: [] __blkdev_put+0x22/0x160 but task is already holding lock: (&REISERFS_SB(s)->lock){+.+.+.}, at: [] reiserfs_write_lock+0x29/0x40 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&REISERFS_SB(s)->lock){+.+.+.}: [] __lock_acquire+0x11ff/0x19e0 [] lock_acquire+0x68/0x90 [] mutex_lock_nested+0x5b/0x340 [] reiserfs_write_lock_once+0x29/0x50 [] reiserfs_get_block+0x85/0x1620 [] do_mpage_readpage+0x1f0/0x6d0 [] mpage_readpages+0xc0/0x100 [] reiserfs_readpages+0x19/0x20 [] __do_page_cache_readahead+0x1bc/0x260 [] ra_submit+0x28/0x40 [] filemap_fault+0x40e/0x420 [] __do_fault+0x3d/0x430 [] handle_mm_fault+0x12e/0x790 [] do_page_fault+0x135/0x330 [] error_code+0x6b/0x70 [] load_elf_binary+0x82a/0x1a10 [] search_binary_handler+0x90/0x1d0 [] do_execve+0x1df/0x250 [] sys_execve+0x46/0x70 [] syscall_call+0x7/0xb -> #2 (&mm->mmap_sem){++++++}: [] __lock_acquire+0x11ff/0x19e0 [] lock_acquire+0x68/0x90 [] might_fault+0x8b/0xb0 [] copy_to_user+0x32/0x70 [] filldir64+0xa4/0xf0 [] sysfs_readdir+0x116/0x210 [] vfs_readdir+0x8d/0xb0 [] sys_getdents64+0x69/0xb0 [] sysenter_do_call+0x12/0x32 -> #1 (sysfs_mutex){+.+.+.}: [] __lock_acquire+0x11ff/0x19e0 [] lock_acquire+0x68/0x90 [] mutex_lock_nested+0x5b/0x340 [] sysfs_addrm_start+0x2c/0xb0 [] create_dir+0x40/0x90 [] sysfs_create_dir+0x2b/0x50 [] kobject_add_internal+0xc2/0x1b0 [] kobject_add_varg+0x31/0x50 [] kobject_add+0x2c/0x60 [] device_add+0x94/0x560 [] add_partition+0x18a/0x2a0 [] rescan_partitions+0x33a/0x450 [] __blkdev_get+0x12f/0x2d0 [] blkdev_get+0xa/0x10 [] register_disk+0x108/0x130 [] add_disk+0xd9/0x130 [] sd_probe_async+0x105/0x1d0 [] async_thread+0xcf/0x230 [] kthread+0x74/0x80 [] kernel_thread_helper+0x7/0x3c -> #0 (&bdev->bd_mutex){+.+.+.}: [] __lock_acquire+0x18f6/0x19e0 [] lock_acquire+0x68/0x90 [] mutex_lock_nested+0x5b/0x340 [] __blkdev_put+0x22/0x160 [] blkdev_put+0xa/0x10 [] free_journal_ram+0xd2/0x130 [] do_journal_release+0x98/0x190 [] journal_release+0xa/0x10 [] reiserfs_put_super+0x36/0x130 [] generic_shutdown_super+0x4f/0xe0 [] kill_block_super+0x25/0x40 [] reiserfs_kill_sb+0x7f/0x90 [] deactivate_super+0x7a/0x90 [] mntput_no_expire+0x98/0xd0 [] sys_umount+0x4c/0x310 [] sys_oldumount+0x19/0x20 [] sysenter_do_call+0x12/0x32 other info that might help us debug this: 2 locks held by umount/3904: #0: (&type->s_umount_key#30){+++++.}, at: [] deactivate_super+0x75/0x90 #1: (&REISERFS_SB(s)->lock){+.+.+.}, at: [] reiserfs_write_lock+0x29/0x40 stack backtrace: Pid: 3904, comm: umount Not tainted 2.6.32-atom #172 Call Trace: [] ? printk+0x18/0x1a [] print_circular_bug+0xca/0xd0 [] __lock_acquire+0x18f6/0x19e0 [] ? free_pcppages_bulk+0x1f/0x250 [] lock_acquire+0x68/0x90 [] ? __blkdev_put+0x22/0x160 [] ? __blkdev_put+0x22/0x160 [] mutex_lock_nested+0x5b/0x340 [] ? __blkdev_put+0x22/0x160 [] ? mark_held_locks+0x62/0x80 [] ? kfree+0x92/0xd0 [] __blkdev_put+0x22/0x160 [] ? trace_hardirqs_on+0xb/0x10 [] blkdev_put+0xa/0x10 [] free_journal_ram+0xd2/0x130 [] do_journal_release+0x98/0x190 [] journal_release+0xa/0x10 [] reiserfs_put_super+0x36/0x130 [] ? up_write+0x16/0x30 [] generic_shutdown_super+0x4f/0xe0 [] kill_block_super+0x25/0x40 [] ? vfs_quota_off+0x0/0x20 [] reiserfs_kill_sb+0x7f/0x90 [] deactivate_super+0x7a/0x90 [] mntput_no_expire+0x98/0xd0 [] sys_umount+0x4c/0x310 [] sys_oldumount+0x19/0x20 [] sysenter_do_call+0x12/0x32 Signed-off-by: Frederic Weisbecker Cc: Alexander Beregalov Cc: Chris Mason Cc: Ingo Molnar --- fs/reiserfs/journal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c index a059879..83ac4d3 100644 --- a/fs/reiserfs/journal.c +++ b/fs/reiserfs/journal.c @@ -2009,10 +2009,11 @@ static int do_journal_release(struct reiserfs_transaction_handle *th, destroy_workqueue(commit_wq); commit_wq = NULL; } - reiserfs_write_lock(sb); free_journal_ram(sb); + reiserfs_write_lock(sb); + return 0; } -- 1.8.2.3