Commit 09e05d48 introduced a wait for transaction commit into journal_unmap_buffer() in the case we are truncating a buffer undergoing commit in the page stradding i_size on a filesystem with blocksize < pagesize. Sadly we forgot to drop buffer lock before waiting for transaction commit and thus deadlock is possible when kjournald wants to lock the buffer. Fix the problem by dropping the buffer lock before waiting for transaction commit. Since we are still holding page lock (and that is OK), buffer cannot disappear under us. CC: stable@vger.kernel.org # Wherever commit 09e05d48 was taken Signed-off-by: Jan Kara <jack@suse.cz>
ext3 users of data=journal mode with blocksize < pagesize were occasionally hitting assertion failure in journal_commit_transaction() checking whether the transaction has at least as many credits reserved as buffers attached. The core of the problem is that when a file gets truncated, buffers that still need checkpointing or that are attached to the committing transaction are left with buffer_mapped set. When this happens to buffers beyond i_size attached to a page stradding i_size, subsequent write extending the file will see these buffers and as they are mapped (but underlying blocks were freed) things go awry from here. The assertion failure just coincidentally (and in this case luckily as we would start corrupting filesystem) triggers due to journal_head not being properly cleaned up as well. Under some rare circumstances this bug could even hit data=ordered mode users. There the assertion won't trigger and we would end up corrupting the filesystem. We fix the problem by unmapping buffers if possible (in lots of cases we just need a buffer attached to a transaction as a place holder but it must not be written out anyway). And in one case, we just have to bite the bullet and wait for transaction commit to finish. Reviewed-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Jan Kara <jack@suse.cz>
This sequence:
results in an IO error when unmounting the RO filesystem. The bug was
introduced by:
commit 9754e39c7bc51328f145e933bfb0df47cd67b6e9
Author: Jan Kara <jack@suse.cz>
Date: Sat Apr 7 12:33:03 2012 +0200
jbd: Split updating of journal superblock and marking journal empty
which lost some of the magic in journal_update_superblock() which
used to test for a journal with no outstanding transactions.
This is a port of a jbd2 fix by Eric Sandeen.
CC: <stable@vger.kernel.org> # 3.4.x
Signed-off-by: Jan Kara <jack@suse.cz>
The '->write_super' superblock method is gone, and this patch removes all the references to 'write_super' from various jbd and jbd2. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jan Kara <jack@suse.cz> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
blkdev_issue_flush() can fail. Make sure the error gets properly propagated. Signed-off-by: Jan Kara <jack@suse.cz>
If journal superblock is written only in disk's caches and other transaction starts reusing space of the transaction cleaned from the log, it can happen blocks of a new transaction reach the disk before journal superblock. When power failure happens in such case, subsequent journal replay would still try to replay the old transaction but some of it's blocks may be already overwritten by the new transaction. For this reason we must use WRITE_FUA when updating log tail and we must first write new log tail to disk and update in-memory information only after that. Signed-off-by: Jan Kara <jack@suse.cz>
There are some log tail updates that are not protected by j_checkpoint_mutex. Some of these are harmless because they happen during startup or shutdown but updates in journal_commit_transaction() and journal_flush() can really race with other log tail updates (e.g. someone doing journal_flush() with someone running cleanup_journal_tail()). So protect all log tail updates with j_checkpoint_mutex. Signed-off-by: Jan Kara <jack@suse.cz>
There are three case of updating journal superblock. In the first case, we want to mark journal as empty (setting s_sequence to 0), in the second case we want to update log tail, in the third case we want to update s_errno. Split these cases into separate functions. It makes the code slightly more straightforward and later patches will make the distinction even more important. Signed-off-by: Jan Kara <jack@suse.cz>
Currently we write out all journal buffers in WRITE_SYNC mode. This improves performance for fsync heavy workloads but hinders performance when writes are mostly asynchronous, most noticably it slows down readers and users complain about slow desktop response etc. So submit writes as asynchronous in the normal case and only submit writes as WRITE_SYNC if we detect someone is waiting for current transaction commit. I've gathered some numbers to back this change. The first is the read latency test. It measures time to read 1 MB after several seconds of sleeping in presence of streaming writes. Top 10 times (out of 90) in us: Before After 2131586 697473 1709932 557487 1564598 535642 1480462 347573 1478579 323153 1408496 222181 1388960 181273 1329565 181070 1252486 172832 1223265 172278 Average: 619377 82180 So the improvement in both maximum and average latency is massive. I've measured fsync throughput by: fs_mark -n 100 -t 1 -s 16384 -d /mnt/fsync/ -S 1 -L 4 in presence of streaming reader. The numbers (fsyncs/s) are: Before After 9.9 6.3 6.8 6.0 6.3 6.2 5.8 6.1 So fsync performance seems unharmed by this change. Signed-off-by: Jan Kara <jack@suse.cz>
Pull power management updates for 3.4 from Rafael Wysocki: "Assorted extensions and fixes including: * Introduction of early/late suspend/hibernation device callbacks. * Generic PM domains extensions and fixes. * devfreq updates from Axel Lin and MyungJoo Ham. * Device PM QoS updates. * Fixes of concurrency problems with wakeup sources. * System suspend and hibernation fixes." * tag 'pm-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (43 commits) PM / Domains: Check domain status during hibernation restore of devices PM / devfreq: add relation of recommended frequency. PM / shmobile: Make MTU2 driver use pm_genpd_dev_always_on() PM / shmobile: Make CMT driver use pm_genpd_dev_always_on() PM / shmobile: Make TMU driver use pm_genpd_dev_always_on() PM / Domains: Introduce "always on" device flag PM / Domains: Fix hibernation restore of devices, v2 PM / Domains: Fix handling of wakeup devices during system resume sh_mmcif / PM: Use PM QoS latency constraint tmio_mmc / PM: Use PM QoS latency constraint PM / QoS: Make it possible to expose PM QoS latency constraints PM / Sleep: JBD and JBD2 missing set_freezable() PM / Domains: Fix include for PM_GENERIC_DOMAINS=n case PM / Freezer: Remove references to TIF_FREEZE in comments PM / Sleep: Add more wakeup source initialization routines PM / Hibernate: Enable usermodehelpers in hibernate() error path PM / Sleep: Make __pm_stay_awake() delete wakeup source timers PM / Sleep: Fix race conditions related to wakeup source timer function PM / Sleep: Fix possible infinite loop during wakeup source destruction PM / Hibernate: print physical addresses consistently with other parts of kernel ...