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From: Dave Chinner <david@fromorbit.com>
To: xfs@oss.sgi.com
Subject: [PATCH 088/102] xfs: protect xfs_sync_worker with s_umount semaphore
Date: Thu, 23 Aug 2012 15:02:46 +1000	[thread overview]
Message-ID: <1345698180-13612-89-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1345698180-13612-1-git-send-email-david@fromorbit.com>

From: Ben Myers <bpm@sgi.com>

Upstream commit: 1307bbd2af67283131728637e9489002adb26f10

xfs_sync_worker checks the MS_ACTIVE flag in s_flags to avoid doing
work during mount and unmount.  This flag can be cleared by unmount
after the xfs_sync_worker checks it but before the work is completed.
The has caused crashes in the completion handler for the dummy
transaction commited by xfs_sync_worker:

PID: 27544  TASK: ffff88013544e040  CPU: 3   COMMAND: "kworker/3:0"
 #0 [ffff88016fdff930] machine_kexec at ffffffff810244e9
 #1 [ffff88016fdff9a0] crash_kexec at ffffffff8108d053
 #2 [ffff88016fdffa70] oops_end at ffffffff813ad1b8
 #3 [ffff88016fdffaa0] no_context at ffffffff8102bd48
 #4 [ffff88016fdffaf0] __bad_area_nosemaphore at ffffffff8102c04d
 #5 [ffff88016fdffb40] bad_area_nosemaphore at ffffffff8102c12e
 #6 [ffff88016fdffb50] do_page_fault at ffffffff813afaee
 #7 [ffff88016fdffc60] page_fault at ffffffff813ac635
    [exception RIP: xlog_get_lowest_lsn+0x30]
    RIP: ffffffffa04a9910  RSP: ffff88016fdffd10  RFLAGS: 00010246
    RAX: ffffc90014e48000  RBX: ffff88014d879980  RCX: ffff88014d879980
    RDX: ffff8802214ee4c0  RSI: 0000000000000000  RDI: 0000000000000000
    RBP: ffff88016fdffd10   R8: ffff88014d879a80   R9: 0000000000000000
    R10: 0000000000000001  R11: 0000000000000000  R12: ffff8802214ee400
    R13: ffff88014d879980  R14: 0000000000000000  R15: ffff88022fd96605
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #8 [ffff88016fdffd18] xlog_state_do_callback at ffffffffa04aa186 [xfs]
 #9 [ffff88016fdffd98] xlog_state_done_syncing at ffffffffa04aa568 [xfs]

Protect xfs_sync_worker by using the s_umount semaphore at the read
level to provide exclusion with unmount while work is progressing.

Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
---
 fs/xfs/linux-2.6/xfs_sync.c |   31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index ccb77cf..74ea9b1 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -470,21 +470,24 @@ xfs_sync_worker(
 	 * We shouldn't write/force the log if we are in the mount/unmount
 	 * process or on a read only filesystem. The workqueue still needs to be
 	 * active in both cases, however, because it is used for inode reclaim
-	 * during these times. hence use the MS_ACTIVE flag to avoid doing
-	 * anything in these periods.
+	 * during these times.  Use the s_umount semaphore to provide exclusion
+	 * with unmount.
 	 */
-	if (!(mp->m_super->s_flags & MS_ACTIVE) &&
-	    !(mp->m_flags & XFS_MOUNT_RDONLY)) {
-		/* dgc: errors ignored here */
-		if (mp->m_super->s_frozen == SB_UNFROZEN &&
-		    xfs_log_need_covered(mp))
-			error = xfs_fs_log_dummy(mp);
-		else
-			xfs_log_force(mp, 0);
-		error = xfs_qm_sync(mp, SYNC_TRYLOCK);
-
-		/* start pushing all the metadata that is currently dirty */
-		xfs_ail_push_all(mp->m_ail);
+	if (down_read_trylock(&mp->m_super->s_umount)) {
+		if (!(mp->m_super->s_flags & MS_ACTIVE) &&
+		    !(mp->m_flags & XFS_MOUNT_RDONLY)) {
+			/* dgc: errors ignored here */
+			if (mp->m_super->s_frozen == SB_UNFROZEN &&
+			    xfs_log_need_covered(mp))
+				error = xfs_fs_log_dummy(mp);
+			else
+				xfs_log_force(mp, 0);
+			error = xfs_qm_sync(mp, SYNC_TRYLOCK);
+
+			/* start pushing all the metadata that is currently dirty */
+			xfs_ail_push_all(mp->m_ail);
+		}
+		up_read(&mp->m_super->s_umount);
 	}
 
 	/* queue us up again */
-- 
1.7.10

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  parent reply	other threads:[~2012-08-23  5:05 UTC|newest]

Thread overview: 117+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-23  5:01 [RFC, PATCH 0/102]: xfs: 3.0.x stable kernel update Dave Chinner
2012-08-23  5:01 ` [PATCH 001/102] xfs: don't serialise adjacent concurrent direct IO appending writes Dave Chinner
2012-08-23  5:01 ` [PATCH 002/102] xfs: remove dead ENODEV handling in xfs_destroy_ioend Dave Chinner
2012-08-23  5:01 ` [PATCH 003/102] xfs: defer AIO/DIO completions Dave Chinner
2012-08-23  5:01 ` [PATCH 004/102] xfs: reduce ioend latency Dave Chinner
2012-08-23  5:01 ` [PATCH 005/102] xfs: wait for I/O completion when writing out pages in xfs_setattr_size Dave Chinner
2012-08-23  5:01 ` [PATCH 006/102] xfs: improve ioend error handling Dave Chinner
2012-08-23  5:01 ` [PATCH 007/102] xfs: Check the return value of xfs_buf_get() Dave Chinner
2012-08-23  5:01 ` [PATCH 008/102] xfs: Check the return value of xfs_trans_get_buf() Dave Chinner
2012-08-23  5:01 ` [PATCH 009/102] xfs: dont ignore error code from xfs_bmbt_update Dave Chinner
2012-08-23  5:01 ` [PATCH 010/102] xfs: fix possible overflow in xfs_ioc_trim() Dave Chinner
2012-08-23  5:01 ` [PATCH 011/102] xfs: XFS_TRANS_SWAPEXT is not a valid flag for Dave Chinner
2012-08-23  5:01 ` [PATCH 012/102] xfs: Don't allocate new buffers on every call to _xfs_buf_find Dave Chinner
2012-08-23  5:01 ` [PATCH 013/102] xfs: reduce the number of log forces from tail pushing Dave Chinner
2012-08-23  5:01 ` [PATCH 014/102] xfs: optimize fsync on directories Dave Chinner
2012-08-23  5:01 ` [PATCH 015/102] xfs: clean up buffer allocation Dave Chinner
2012-08-23  5:01 ` [PATCH 016/102] xfs: clean up xfs_ioerror_alert Dave Chinner
2012-08-23  5:01 ` [PATCH 017/102] xfs: use xfs_ioerror_alert in xfs_buf_iodone_callbacks Dave Chinner
2012-08-23  5:01 ` [PATCH 018/102] xfs: do not flush data workqueues in xfs_flush_buftarg Dave Chinner
2012-08-23  5:01 ` [PATCH 019/102] xfs: add AIL pushing tracepoints Dave Chinner
2012-08-23  5:01 ` [PATCH 020/102] xfs: warn if direct reclaim tries to writeback pages Dave Chinner
2012-08-27 18:17   ` Christoph Hellwig
2012-09-05 11:32     ` Mel Gorman
2012-09-13 20:12       ` Mark Tinguely
2012-09-14  9:45         ` Mel Gorman
2012-09-14 12:56           ` Mark Tinguely
2012-09-14 16:18             ` Mark Tinguely
2012-08-23  5:01 ` [PATCH 021/102] xfs: fix force shutdown handling in xfs_end_io Dave Chinner
2012-08-23  5:01 ` [PATCH 022/102] xfs: fix allocation length overflow in xfs_bmapi_write() Dave Chinner
2012-08-23  5:01 ` [PATCH 023/102] xfs: fix the logspace waiting algorithm Dave Chinner
2012-08-23  5:01 ` [PATCH 024/102] xfs: untangle SYNC_WAIT and SYNC_TRYLOCK meanings for xfs_qm_dqflush Dave Chinner
2012-08-23  5:01 ` [PATCH 025/102] xfs: make sure to really flush all dquots in xfs_qm_quotacheck Dave Chinner
2012-08-23  5:01 ` [PATCH 026/102] xfs: simplify xfs_qm_detach_gdquots Dave Chinner
2012-08-23  5:01 ` [PATCH 027/102] xfs: mark the xfssyncd workqueue as non-reentrant Dave Chinner
2012-08-23  5:01 ` [PATCH 028/102] xfs: make i_flags an unsigned long Dave Chinner
2012-08-23  5:01 ` [PATCH 029/102] xfs: remove the i_size field in struct xfs_inode Dave Chinner
2012-08-23  5:01 ` [PATCH 030/102] xfs: remove the i_new_size " Dave Chinner
2012-08-23  5:01 ` [PATCH 031/102] xfs: always return with the iolock held from Dave Chinner
2012-08-23  5:01 ` [PATCH 032/102] xfs: cleanup xfs_file_aio_write Dave Chinner
2012-08-23  5:01 ` [PATCH 033/102] xfs: pass KM_SLEEP flag to kmem_realloc() in Dave Chinner
2012-08-23  5:01 ` [PATCH 034/102] xfs: show uuid when mount fails due to duplicate uuid Dave Chinner
2012-08-23  5:01 ` [PATCH 035/102] xfs: xfs_trans_add_item() - don't assign in ASSERT() when compare is intended Dave Chinner
2012-08-23  5:01 ` [PATCH 036/102] xfs: split tail_lsn assignments from log space wakeups Dave Chinner
2012-08-23  5:01 ` [PATCH 037/102] xfs: do exact log space wakeups in xlog_ungrant_log_space Dave Chinner
2012-08-23  5:01 ` [PATCH 038/102] xfs: remove xfs_trans_unlocked_item Dave Chinner
2012-08-23  5:01 ` [PATCH 039/102] xfs: cleanup xfs_log_space_wake Dave Chinner
2012-08-23  5:01 ` [PATCH 040/102] xfs: remove log space waitqueues Dave Chinner
2012-08-23  5:01 ` [PATCH 041/102] xfs: add the xlog_grant_head structure Dave Chinner
2012-08-23  5:02 ` [PATCH 042/102] xfs: add xlog_grant_head_init Dave Chinner
2012-08-23  5:02 ` [PATCH 043/102] xfs: add xlog_grant_head_wake_all Dave Chinner
2012-08-23  5:02 ` [PATCH 044/102] xfs: share code for grant head waiting Dave Chinner
2012-08-23  5:02 ` [PATCH 045/102] xfs: share code for grant head wakeups Dave Chinner
2012-08-23  5:02 ` [PATCH 046/102] xfs: share code for grant head availability checks Dave Chinner
2012-08-23  5:02 ` [PATCH 047/102] xfs: split and cleanup xfs_log_reserve Dave Chinner
2012-08-23  5:02 ` [PATCH 048/102] xfs: only take the ILOCK in xfs_reclaim_inode() Dave Chinner
2012-08-23  5:02 ` [PATCH 049/102] xfs: use per-filesystem I/O completion workqueues Dave Chinner
2012-08-23  5:02 ` [PATCH 050/102] xfs: do not require an ioend for new EOF calculation Dave Chinner
2012-08-23  5:02 ` [PATCH 054/102] xfs: make xfs_inode_item_size idempotent Dave Chinner
2012-08-23  5:02 ` [PATCH 055/102] xfs: split in-core and on-disk inode log item fields Dave Chinner
2012-08-23  5:02 ` [PATCH 056/102] xfs: reimplement fdatasync support Dave Chinner
2012-08-23  5:02 ` [PATCH 057/102] xfs: fallback to vmalloc for large buffers in xfs_attrmulti_attr_get Dave Chinner
2012-08-23  5:02 ` [PATCH 058/102] xfs: fallback to vmalloc for large buffers in xfs_getbmap Dave Chinner
2012-08-23  5:02 ` [PATCH 059/102] xfs: fix deadlock in xfs_rtfree_extent Dave Chinner
2012-08-23  5:02 ` [PATCH 060/102] xfs: Fix open flag handling in open_by_handle code Dave Chinner
2012-08-23  5:02 ` [PATCH 061/102] xfs: introduce an allocation workqueue Dave Chinner
2012-08-23  5:02 ` [PATCH 062/102] xfs: trace xfs_name strings correctly Dave Chinner
2012-08-23  5:02 ` [PATCH 063/102] xfs: Account log unmount transaction correctly Dave Chinner
2012-08-23  5:02 ` [PATCH 064/102] xfs: fix fstrim offset calculations Dave Chinner
2012-08-23  5:02 ` [PATCH 065/102] xfs: add lots of attribute trace points Dave Chinner
2012-08-23  5:02 ` [PATCH 066/102] xfs: don't fill statvfs with project quota for a directory Dave Chinner
2012-08-23  5:02 ` [PATCH 067/102] xfs: Ensure inode reclaim can run during quotacheck Dave Chinner
2012-08-23  5:02 ` [PATCH 068/102] xfs: avoid taking the ilock unnessecarily in xfs_qm_dqattach Dave Chinner
2012-08-23  5:02 ` [PATCH 069/102] xfs: reduce ilock hold times in xfs_file_aio_write_checks Dave Chinner
2012-08-23  5:02 ` [PATCH 070/102] xfs: reduce ilock hold times in xfs_setattr_size Dave Chinner
2012-08-23  5:02 ` [PATCH 071/102] xfs: push the ilock into xfs_zero_eof Dave Chinner
2012-08-23  5:02 ` [PATCH 072/102] xfs: use shared ilock mode for direct IO writes by default Dave Chinner
2012-08-23  5:02 ` [PATCH 073/102] xfs: punch all delalloc blocks beyond EOF on write failure Dave Chinner
2012-08-23  5:02 ` [PATCH 074/102] xfs: using GFP_NOFS for blkdev_issue_flush Dave Chinner
2012-08-23  5:02 ` [PATCH 075/102] xfs: page type check in writeback only checks last buffer Dave Chinner
2012-08-23  5:02 ` [PATCH 076/102] xfs: punch new delalloc blocks out of failed writes inside Dave Chinner
2012-08-23  5:02 ` [PATCH 077/102] xfs: prevent needless mount warning causing test failures Dave Chinner
2012-08-23  5:02 ` [PATCH 078/102] xfs: don't assert on delalloc regions beyond EOF Dave Chinner
2012-08-23  5:02 ` [PATCH 079/102] xfs: limit specualtive delalloc to maxioffset Dave Chinner
2012-08-23  5:02 ` [PATCH 080/102] xfs: Use preallocation for inodes with extsz hints Dave Chinner
2012-08-23  5:02 ` [PATCH 081/102] xfs: fix buffer lookup race on allocation failure Dave Chinner
2012-08-23  5:02 ` [PATCH 082/102] xfs: check for buffer errors before waiting Dave Chinner
2012-08-23  5:02 ` [PATCH 083/102] xfs: fix incorrect b_offset initialisation Dave Chinner
2012-08-23  5:02 ` [PATCH 084/102] xfs: use kmem_zone_zalloc for buffers Dave Chinner
2012-08-23  5:02 ` [PATCH 085/102] xfs: use iolock on XFS_IOC_ALLOCSP calls Dave Chinner
2012-08-23  5:02 ` [PATCH 086/102] xfs: Properly exclude IO type flags from buffer flags Dave Chinner
2012-08-23  5:02 ` [PATCH 087/102] xfs: flush outstanding buffers on log mount failure Dave Chinner
2012-08-23  5:02 ` Dave Chinner [this message]
2012-08-23  5:02 ` [PATCH 089/102] xfs: fix memory reclaim deadlock on agi buffer Dave Chinner
2012-08-23  5:02 ` [PATCH 090/102] xfs: add trace points for log forces Dave Chinner
2012-08-23  5:02 ` [PATCH 091/102] xfs: switch to proper __bitwise type for KM_... flags Dave Chinner
2012-08-23  5:02 ` [PATCH 092/102] xfs: xfs_vm_writepage clear iomap_valid when Dave Chinner
2012-08-23  5:02 ` [PATCH 093/102] xfs: fix debug_object WARN at xfs_alloc_vextent() Dave Chinner
2012-08-23  5:02 ` [PATCH 094/102] xfs: m_maxioffset is redundant Dave Chinner
2012-08-23  5:02 ` [PATCH 095/102] xfs: make largest supported offset less shouty Dave Chinner
2012-08-23  5:02 ` [PATCH 096/102] xfs: kill copy and paste segment checks in xfs_file_aio_read Dave Chinner
2012-08-23  5:02 ` [PATCH 097/102] xfs: fix allocbt cursor leak in xfs_alloc_ag_vextent_near Dave Chinner
2012-08-23  5:02 ` [PATCH 098/102] xfs: shutdown xfs_sync_worker before the log Dave Chinner
2012-08-23  5:02 ` [PATCH 099/102] xfs: really fix the cursor leak in xfs_alloc_ag_vextent_near Dave Chinner
2012-08-23  5:02 ` [PATCH 100/102] xfs: don't defer metadata allocation to the workqueue Dave Chinner
2012-08-23  5:02 ` [PATCH 101/102] xfs: prevent recursion in xfs_buf_iorequest Dave Chinner
2012-08-23  5:03 ` [PATCH 102/102] xfs: handle EOF correctly in xfs_vm_writepage Dave Chinner
2012-08-23 21:54 ` [RFC, PATCH 0/102]: xfs: 3.0.x stable kernel update Dave Chinner
2012-08-23 22:14   ` Ben Myers
2012-08-23 22:23   ` Matthias Schniedermeyer
2012-09-01 23:10 ` Christoph Hellwig
2012-09-03  6:04   ` Dave Chinner
2012-09-04 21:13     ` Ben Myers
2012-09-05  4:24       ` Dave Chinner
2012-09-13 18:32 ` Mark Tinguely
2012-09-18 13:59 ` Mark Tinguely
2012-09-18 23:50   ` Dave Chinner
2012-09-19 13:14     ` Mark Tinguely

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