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2011-07-09writeback: scale IO chunk size up to half device bandwidthWu Fengguang
Originally, MAX_WRITEBACK_PAGES was hard-coded to 1024 because of a concern of not holding I_SYNC for too long. (At least, that was the comment previously.) This doesn't make sense now because the only time we wait for I_SYNC is if we are calling sync or fsync, and in that case we need to write out all of the data anyway. Previously there may have been other code paths that waited on I_SYNC, but not any more. -- Theodore Ts'o So remove the MAX_WRITEBACK_PAGES constraint. The writeback pages will adapt to as large as the storage device can write within 500ms. XFS is observed to do IO completions in a batch, and the batch size is equal to the write chunk size. To avoid dirty pages to suddenly drop out of balance_dirty_pages()'s dirty control scope and create large fluctuations, the chunk size is also limited to half the control scope. The balance_dirty_pages() control scrope is [(background_thresh + dirty_thresh) / 2, dirty_thresh] which is by default [15%, 20%] of global dirty pages, whose range size is dirty_thresh / DIRTY_FULL_SCOPE. The adpative write chunk size will be rounded to the nearest 4MB boundary. http://bugzilla.kernel.org/show_bug.cgi?id=13930 CC: Theodore Ts'o <tytso@mit.edu> CC: Dave Chinner <david@fromorbit.com> CC: Chris Mason <chris.mason@oracle.com> CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-07-09writeback: introduce smoothed global dirty limitWu Fengguang
The start of a heavy weight application (ie. KVM) may instantly knock down determine_dirtyable_memory() if the swap is not enabled or full. global_dirty_limits() and bdi_dirty_limit() will in turn get global/bdi dirty thresholds that are _much_ lower than the global/bdi dirty pages. balance_dirty_pages() will then heavily throttle all dirtiers including the light ones, until the dirty pages drop below the new dirty thresholds. During this _deep_ dirty-exceeded state, the system may appear rather unresponsive to the users. About "deep" dirty-exceeded: task_dirty_limit() assigns 1/8 lower dirty threshold to heavy dirtiers than light ones, and the dirty pages will be throttled around the heavy dirtiers' dirty threshold and reasonably below the light dirtiers' dirty threshold. In this state, only the heavy dirtiers will be throttled and the dirty pages are carefully controlled to not exceed the light dirtiers' dirty threshold. However if the threshold itself suddenly drops below the number of dirty pages, the light dirtiers will get heavily throttled. So introduce global_dirty_limit for tracking the global dirty threshold with policies - follow downwards slowly - follow up in one shot global_dirty_limit can effectively mask out the impact of sudden drop of dirtyable memory. It will be used in the next patch for two new type of dirty limits. Note that the new dirty limits are not going to avoid throttling the light dirtiers, but could limit their sleep time to 200ms. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-07-09writeback: bdi write bandwidth estimationWu Fengguang
The estimation value will start from 100MB/s and adapt to the real bandwidth in seconds. It tries to update the bandwidth only when disk is fully utilized. Any inactive period of more than one second will be skipped. The estimated bandwidth will be reflecting how fast the device can writeout when _fully utilized_, and won't drop to 0 when it goes idle. The value will remain constant at disk idle time. At busy write time, if not considering fluctuations, it will also remain high unless be knocked down by possible concurrent reads that compete for the disk time and bandwidth with async writes. The estimation is not done purely in the flusher because there is no guarantee for write_cache_pages() to return timely to update bandwidth. The bdi->avg_write_bandwidth smoothing is very effective for filtering out sudden spikes, however may be a little biased in long term. The overheads are low because the bdi bandwidth update only occurs at 200ms intervals. The 200ms update interval is suitable, because it's not possible to get the real bandwidth for the instance at all, due to large fluctuations. The NFS commits can be as large as seconds worth of data. One XFS completion may be as large as half second worth of data if we are going to increase the write chunk to half second worth of data. In ext4, fluctuations with time period of around 5 seconds is observed. And there is another pattern of irregular periods of up to 20 seconds on SSD tests. That's why we are not only doing the estimation at 200ms intervals, but also averaging them over a period of 3 seconds and then go further to do another level of smoothing in avg_write_bandwidth. CC: Li Shaohua <shaohua.li@intel.com> CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-07-09writeback: make writeback_control.nr_to_write straightWu Fengguang
Pass struct wb_writeback_work all the way down to writeback_sb_inodes(), and initialize the struct writeback_control there. struct writeback_control is basically designed to control writeback of a single file, but we keep abuse it for writing multiple files in writeback_sb_inodes() and its callers. It immediately clean things up, e.g. suddenly wbc.nr_to_write vs work->nr_pages starts to make sense, and instead of saving and restoring pages_skipped in writeback_sb_inodes it can always start with a clean zero value. It also makes a neat IO pattern change: large dirty files are now written in the full 4MB writeback chunk size, rather than whatever remained quota in wbc->nr_to_write. Acked-by: Jan Kara <jack@suse.cz> Proposed-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: trace event writeback_queue_ioWu Fengguang
Note that it adds a little overheads to account the moved/enqueued inodes from b_dirty to b_io. The "moved" accounting may be later used to limit the number of inodes that can be moved in one shot, in order to keep spinlock hold time under control. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: trace event writeback_single_inodeWu Fengguang
It is valuable to know how the dirty inodes are iterated and their IO size. "writeback_single_inode: bdi 8:0: ino=134246746 state=I_DIRTY_SYNC|I_SYNC age=414 index=0 to_write=1024 wrote=0" - "state" reflects inode->i_state at the end of writeback_single_inode() - "index" reflects mapping->writeback_index after the ->writepages() call - "to_write" is the wbc->nr_to_write at entrance of writeback_single_inode() - "wrote" is the number of pages actually written v2: add trace event writeback_single_inode_requeue as proposed by Dave. CC: Dave Chinner <david@fromorbit.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: remove .nonblocking and .encountered_congestionWu Fengguang
Remove two unused struct writeback_control fields: .encountered_congestion (completely unused) .nonblocking (never set, checked/showed in XFS,NFS/btrfs) The .for_background check in nfs_write_inode() is also removed btw, as .for_background implies WB_SYNC_NONE. Reviewed-by: Jan Kara <jack@suse.cz> Proposed-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: remove writeback_control.more_ioWu Fengguang
When wbc.more_io was first introduced, it indicates whether there are at least one superblock whose s_more_io contains more IO work. Now with the per-bdi writeback, it can be replaced with a simple b_more_io test. Acked-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: avoid extra sync work at enqueue timeWu Fengguang
This removes writeback_control.wb_start and does more straightforward sync livelock prevention by setting .older_than_this to prevent extra inodes from being enqueued in the first place. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: elevate queue_io() into wb_writeback()Wu Fengguang
Code refactor for more logical code layout. No behavior change. - remove the mis-named __writeback_inodes_sb() - wb_writeback()/writeback_inodes_wb() will decide when to queue_io() before calling __writeback_inodes_wb() Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: split inode_wb_list_lock into bdi_writeback.list_lockChristoph Hellwig
Split the global inode_wb_list_lock into a per-bdi_writeback list_lock, as it's currently the most contended lock in the system for metadata heavy workloads. It won't help for single-filesystem workloads for which we'll need the I/O-less balance_dirty_pages, but at least we can dedicate a cpu to spinning on each bdi now for larger systems. Based on earlier patches from Nick Piggin and Dave Chinner. It reduces lock contentions to 1/4 in this test case: 10 HDD JBOD, 100 dd on each disk, XFS, 6GB ram lock_stat version 0.3 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- vanilla 2.6.39-rc3: inode_wb_list_lock: 42590 44433 0.12 147.74 144127.35 252274 886792 0.08 121.34 917211.23 ------------------ inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85 inode_wb_list_lock 34 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49 inode_wb_list_lock 12893 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0 inode_wb_list_lock 10702 [<ffffffff8115afef>] writeback_single_inode+0x16d/0x20a ------------------ inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85 inode_wb_list_lock 19 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49 inode_wb_list_lock 5550 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0 inode_wb_list_lock 8511 [<ffffffff8115b4ad>] writeback_sb_inodes+0x10f/0x157 2.6.39-rc3 + patch: &(&wb->list_lock)->rlock: 11383 11657 0.14 151.69 40429.51 90825 527918 0.11 145.90 556843.37 ------------------------ &(&wb->list_lock)->rlock 10 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86 &(&wb->list_lock)->rlock 1493 [<ffffffff8115b1ed>] writeback_inodes_wb+0x3d/0x150 &(&wb->list_lock)->rlock 3652 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f &(&wb->list_lock)->rlock 1412 [<ffffffff8115a38e>] writeback_single_inode+0x17f/0x223 ------------------------ &(&wb->list_lock)->rlock 3 [<ffffffff8110b5af>] bdi_lock_two+0x46/0x4b &(&wb->list_lock)->rlock 6 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86 &(&wb->list_lock)->rlock 2061 [<ffffffff8115af97>] __mark_inode_dirty+0x173/0x1cf &(&wb->list_lock)->rlock 2629 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f hughd@google.com: fix recursive lock when bdi_lock_two() is called with new the same as old akpm@linux-foundation.org: cleanup bdev_inode_switch_bdi() comment Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: refill b_io iff emptyWu Fengguang
There is no point to carry different refill policies between for_kupdate and other type of works. Use a consistent "refill b_io iff empty" policy which can guarantee fairness in an easy to understand way. A b_io refill will setup a _fixed_ work set with all currently eligible inodes and start a new round of walk through b_io. The "fixed" work set means no new inodes will be added to the work set during the walk. Only when a complete walk over b_io is done, new inodes that are eligible at the time will be enqueued and the walk be started over. This procedure provides fairness among the inodes because it guarantees each inode to be synced once and only once at each round. So all inodes will be free from starvations. This change relies on wb_writeback() to keep retrying as long as we made some progress on cleaning some pages and/or inodes. Without that ability, the old logic on background works relies on aggressively queuing all eligible inodes into b_io at every time. But that's not a guarantee. The below test script completes a slightly faster now: 2.6.39-rc3 2.6.39-rc3-dyn-expire+ ------------------------------------------------ all elapsed 256.043 252.367 stddev 24.381 12.530 tar elapsed 30.097 28.808 dd elapsed 13.214 11.782 #!/bin/zsh cp /c/linux-2.6.38.3.tar.bz2 /dev/shm/ umount /dev/sda7 mkfs.xfs -f /dev/sda7 mount /dev/sda7 /fs echo 3 > /proc/sys/vm/drop_caches tic=$(cat /proc/uptime|cut -d' ' -f2) cd /fs time tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 & time dd if=/dev/zero of=/fs/zero bs=1M count=1000 & wait sync tac=$(cat /proc/uptime|cut -d' ' -f2) echo elapsed: $((tac - tic)) It maintains roughly the same small vs. large file writeout shares, and offers large files better chances to be written in nice 4M chunks. Analyzes from Dave Chinner in great details: Let's say we have lots of inodes with 100 dirty pages being created, and one large writeback going on. We expire 8 new inodes for every 1024 pages we write back. With the old code, we do: b_more_io (large inode) -> b_io (1l) 8 newly expired inodes -> b_io (1l, 8s) writeback large inode 1024 pages -> b_more_io b_more_io (large inode) -> b_io (8s, 1l) 8 newly expired inodes -> b_io (8s, 1l, 8s) writeback 8 small inodes 800 pages 1 large inode 224 pages -> b_more_io b_more_io (large inode) -> b_io (8s, 1l) 8 newly expired inodes -> b_io (8s, 1l, 8s) ..... Your new code: b_more_io (large inode) -> b_io (1l) 8 newly expired inodes -> b_io (1l, 8s) writeback large inode 1024 pages -> b_more_io (b_io == 8s) writeback 8 small inodes 800 pages b_io empty: (1800 pages written) b_more_io (large inode) -> b_io (1l) 14 newly expired inodes -> b_io (1l, 14s) writeback large inode 1024 pages -> b_more_io (b_io == 14s) writeback 10 small inodes 1000 pages 1 small inode 24 pages -> b_more_io (1l, 1s(24)) writeback 5 small inodes 500 pages b_io empty: (2548 pages written) b_more_io (large inode) -> b_io (1l, 1s(24)) 20 newly expired inodes -> b_io (1l, 1s(24), 20s) ...... Rough progression of pages written at b_io refill: Old code: total large file % of writeback 1024 224 21.9% (fixed) New code: total large file % of writeback 1800 1024 ~55% 2550 1024 ~40% 3050 1024 ~33% 3500 1024 ~29% 3950 1024 ~26% 4250 1024 ~24% 4500 1024 ~22.7% 4700 1024 ~21.7% 4800 1024 ~21.3% 4800 1024 ~21.3% (pretty much steady state from here) Ok, so the steady state is reached with a similar percentage of writeback to the large file as the existing code. Ok, that's good, but providing some evidence that is doesn't change the shared of writeback to the large should be in the commit message ;) The other advantage to this is that we always write 1024 page chunks to the large file, rather than smaller "whatever remains" chunks. CC: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: the kupdate expire timestamp should be a moving targetWu Fengguang
Dynamically compute the dirty expire timestamp at queue_io() time. writeback_control.older_than_this used to be determined at entrance to the kupdate writeback work. This _static_ timestamp may go stale if the kupdate work runs on and on. The flusher may then stuck with some old busy inodes, never considering newly expired inodes thereafter. This has two possible problems: - It is unfair for a large dirty inode to delay (for a long time) the writeback of small dirty inodes. - As time goes by, the large and busy dirty inode may contain only _freshly_ dirtied pages. Ignoring newly expired dirty inodes risks delaying the expired dirty pages to the end of LRU lists, triggering the evil pageout(). Nevertheless this patch merely addresses part of the problem. v2: keep policy changes inside wb_writeback() and keep the wbc.older_than_this visibility as suggested by Dave. CC: Dave Chinner <david@fromorbit.com> Acked-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Itaru Kitayama <kitayama@cl.bb4u.ne.jp> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: try more writeback as long as something was writtenWu Fengguang
writeback_inodes_wb()/__writeback_inodes_sb() are not aggressive in that they only populate possibly a subset of eligible inodes into b_io at entrance time. When the queued set of inodes are all synced, they just return, possibly with all queued inode pages written but still wbc.nr_to_write > 0. For kupdate and background writeback, there may be more eligible inodes sitting in b_dirty when the current set of b_io inodes are completed. So it is necessary to try another round of writeback as long as we made some progress in this round. When there are no more eligible inodes, no more inodes will be enqueued in queue_io(), hence nothing could/will be synced and we may safely bail. For example, imagine 100 inodes i0, i1, i2, ..., i90, i91, i99 At queue_io() time, i90-i99 happen to be expired and moved to s_io for IO. When finished successfully, if their total size is less than MAX_WRITEBACK_PAGES, nr_to_write will be > 0. Then wb_writeback() will quit the background work (w/o this patch) while it's still over background threshold. This will be a fairly normal/frequent case I guess. Now that we do tagged sync and update inode->dirtied_when after the sync, this change won't livelock sync(1). I actually tried to write 1 page per 1ms with this command write-and-fsync -n10000 -S 1000 -c 4096 /fs/test and do sync(1) at the same time. The sync completes quickly on ext4, xfs, btrfs. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: introduce writeback_control.inodes_writtenWu Fengguang
The flusher works on dirty inodes in batches, and may quit prematurely if the batch of inodes happen to be metadata-only dirtied: in this case wbc->nr_to_write won't be decreased at all, which stands for "no pages written" but also mis-interpreted as "no progress". So introduce writeback_control.inodes_written to count the inodes get cleaned from VFS POV. A non-zero value means there are some progress on writeback, in which case more writeback can be tried. Acked-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: update dirtied_when for synced inode to prevent livelockWu Fengguang
Explicitly update .dirtied_when on synced inodes, so that they are no longer considered for writeback in the next round. It can prevent both of the following livelock schemes: - while true; do echo data >> f; done - while true; do touch f; done (in theory) The exact livelock condition is, during sync(1): (1) no new inodes are dirtied (2) an inode being actively dirtied On (2), the inode will be tagged and synced with .nr_to_write=LONG_MAX. When finished, it will be redirty_tail()ed because it's still dirty and (.nr_to_write > 0). redirty_tail() won't update its ->dirtied_when on condition (1). The sync work will then revisit it on the next queue_io() and find it eligible again because its old ->dirtied_when predates the sync work start time. We'll do more aggressive "keep writeback as long as we wrote something" logic in wb_writeback(). The "use LONG_MAX .nr_to_write" trick in commit b9543dac5bbc ("writeback: avoid livelocking WB_SYNC_ALL writeback") will no longer be enough to stop sync livelock. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-08writeback: introduce .tagged_writepages for the WB_SYNC_NONE sync stageWu Fengguang
sync(2) is performed in two stages: the WB_SYNC_NONE sync and the WB_SYNC_ALL sync. Identify the first stage with .tagged_writepages and do livelock prevention for it, too. Jan's commit f446daaea9 ("mm: implement writeback livelock avoidance using page tagging") is a partial fix in that it only fixed the WB_SYNC_ALL phase livelock. Although ext4 is tested to no longer livelock with commit f446daaea9, it may due to some "redirty_tail() after pages_skipped" effect which is by no means a guarantee for _all_ the file systems. Note that writeback_inodes_sb() is called by not only sync(), they are treated the same because the other callers also need livelock prevention. Impact: It changes the order in which pages/inodes are synced to disk. Now in the WB_SYNC_NONE stage, it won't proceed to write the next inode until finished with the current inode. Acked-by: Jan Kara <jack@suse.cz> CC: Dave Chinner <david@fromorbit.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-06-05Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (25 commits) btrfs: fix uninitialized variable warning btrfs: add helper for fs_info->closing Btrfs: add mount -o inode_cache btrfs: scrub: add explicit plugging btrfs: use btrfs_ino to access inode number Btrfs: don't save the inode cache if we are deleting this root btrfs: false BUG_ON when degraded Btrfs: don't save the inode cache in non-FS roots Btrfs: make sure we don't overflow the free space cache crc page Btrfs: fix uninit variable in the delayed inode code btrfs: scrub: don't reuse bios and pages Btrfs: leave spinning on lookup and map the leaf Btrfs: check for duplicate entries in the free space cache Btrfs: don't try to allocate from a block group that doesn't have enough space Btrfs: don't always do readahead Btrfs: try not to sleep as much when doing slow caching Btrfs: kill BTRFS_I(inode)->block_group Btrfs: don't look at the extent buffer level 3 times in a row Btrfs: map the node block when looking for readahead targets Btrfs: set range_start to the right start in count_range_bits ...
2011-06-04btrfs: fix uninitialized variable warningDavid Sterba
With Linus' tree, today's linux-next build (powercp ppc64_defconfig) produced this warning: fs/btrfs/delayed-inode.c: In function 'btrfs_delayed_update_inode': fs/btrfs/delayed-inode.c:1598:6: warning: 'ret' may be used uninitialized in this function Introduced by commit 16cdcec736cd ("btrfs: implement delayed inode items operation"). This fixes a bug in btrfs_update_inode(): if the returned value from btrfs_delayed_update_inode is a nonzero garbage, inode stat data are not updated and several call paths may hit a BUG_ON or fail with strange code. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: David Sterba <dsterba@suse.cz>
2011-06-04btrfs: add helper for fs_info->closingDavid Sterba
wrap checking of filesystem 'closing' flag and fix a few missing memory barriers. Signed-off-by: David Sterba <dsterba@suse.cz>
2011-06-04Btrfs: add mount -o inode_cacheChris Mason
This makes the inode map cache default to off until we fix the overflow problem when the free space crcs don't fit inside a single page. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04btrfs: scrub: add explicit pluggingArne Jansen
With the removal of the implicit plugging scrub ends up doing more and smaller I/O than necessary. This patch adds explicit plugging per chunk. Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04btrfs: use btrfs_ino to access inode numberDavid Sterba
commit 4cb5300bc ("Btrfs: add mount -o auto_defrag") accesses inode number directly while it should use the helper with the new inode number allocator. Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04Btrfs: don't save the inode cache if we are deleting this rootJosef Bacik
With xfstest 254 I can panic the box every time with the inode number caching stuff on. This is because we clean the inodes out when we delete the subvolume, but then we write out the inode cache which adds an inode to the subvolume inode tree, and then when it gets evicted again the root gets added back on the dead roots list and is deleted again, so we have a double free. To stop this from happening just return 0 if refs is 0 (and we're not the tree root since tree root always has refs of 0). With this fix 254 no longer panics. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Tested-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04btrfs: false BUG_ON when degradedArne Jansen
In degraded mode the struct btrfs_device of missing devs don't have device->name set. A kstrdup of NULL correctly returns NULL. Don't BUG in this case. Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04Btrfs: don't save the inode cache in non-FS rootsliubo
This adds extra checks to make sure the inode map we are caching really belongs to a FS root instead of a special relocation tree. It prevents crashes during balancing operations. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04Btrfs: make sure we don't overflow the free space cache crc pageChris Mason
The free space cache uses only one page for crcs right now, which means we can't have a cache file bigger than the crcs we can fit in the first page. This adds a check to enforce that restriction. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04Btrfs: fix uninit variable in the delayed inode codeChris Mason
The nitems counter needs to start at zero Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-04btrfs: scrub: don't reuse bios and pagesArne Jansen
The current scrub implementation reuses bios and pages as often as possible, allocating them only on start and releasing them when finished. This leads to more problems with the block layer than it's worth. The elevator gets confused when there are more pages added to the bio than bi_size suggests. This patch completely rips out the reuse of bios and pages and allocates them freshly for each submit. Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Chris Maosn <chris.mason@oracle.com>
2011-06-04Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-block: block: Use hlist_entry() for io_context.cic_list.first cfq-iosched: Remove bogus check in queue_fail path xen/blkback: potential null dereference in error handling xen/blkback: don't call vbd_size() if bd_disk is NULL block: blkdev_get() should access ->bd_disk only after success CFQ: Fix typo and remove unnecessary semicolon block: remove unwanted semicolons Revert "block: Remove extra discard_alignment from hd_struct." nbd: adjust 'max_part' according to part_shift nbd: limit module parameters to a sane value nbd: pass MSG_* flags to kernel_recvmsg() block: improve the bio_add_page() and bio_add_pc_page() descriptions
2011-06-04Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6Linus Torvalds
* 'linux-next' of git://git.infradead.org/ubifs-2.6: UBIFS: fix-up free space earlier UBIFS: intialize LPT earlier UBIFS: assert no fixup when writing a node UBIFS: fix clean znode counter corruption in error cases UBIFS: fix memory leak on error path UBIFS: fix shrinker object count reports UBIFS: fix recovery broken by the previous recovery fix UBIFS: amend ubifs_recover_leb interface UBIFS: introduce a "grouped" journal head flag UBIFS: supress false error messages
2011-06-03UBIFS: fix-up free space earlierBen Gardiner
The free space fixup is currently initiated during mount after the call to ubifs_write_master() which results in a write to PEBs; this has been observed with the patch 'assert no fixup when writing a node' applied: Move the free space fixup on mount to before the calls to ubifs_recover_inl_heads() and ubifs_write_master(). This results in no assertions with the previously mentioned patch applied. Artem: tweaked the patch a bit Signed-off-by: Ben Gardiner <bengardiner@nanometrics> Reviewed-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: intialize LPT earlierBen Gardiner
The current 'mount_ubifs()' implementation does not initialize the LPT until the the master node is marked dirty. Move the LPT initialization to before marking the master node dirty. This is a preparation for the next patch which will move the free-space-fixup check to before marking the master node dirty, because we have to fix-up the free space before doing any writes. Artem: massaged the patch and commit message. Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca> Reviewed-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: assert no fixup when writing a nodeBen Gardiner
The current free space fixup can result in some writing to the UBI volume when the space_fixup flag is set. To catch instances where UBIFS is writing to the NAND while the space_fixup flag is set, add an assert to ubifs_write_node(). Artem: tweaked the patch, added similar assertion to the write buffer write path. Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca> Reviewed-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: fix clean znode counter corruption in error casesArtem Bityutskiy
UBIFS maintains per-filesystem and global clean znode counters ('c->clean_zn_cnt' and 'ubifs_clean_zn_cnt'). It is important to maintain correct values there since the shrinker relies on 'ubifs_clean_zn_cnt'. However, in case of failures during commit the counters were corrupted. E.g., if a failure happens in the middle of 'write_index()', then some nodes in the commit list ('c->cnext') are marked as clean, and some are marked as dirty. And the 'ubifs_destroy_tnc_subtree()' frees does not retrun correct count, and we end up with non-zero 'c->clean_zn_cnt' when unmounting. This means that if we have 2 file-sytem and one of them fails, and we unmount it, 'ubifs_clean_zn_cnt' stays incorrect and confuses the shrinker. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: fix memory leak on error pathArtem Bityutskiy
UBIFS leaks memory on error path in 'ubifs_jnl_update()' in case of write failure because it forgets to free the 'struct ubifs_dent_node *dent' object. Although the object is small, the alignment can make it large - e.g., 2KiB if the min. I/O unit is 2KiB. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: stable@kernel.org
2011-06-03UBIFS: fix shrinker object count reportsArtem Bityutskiy
Sometimes VM asks the shrinker to return amount of objects it can shrink, and we return the ubifs_clean_zn_cnt in that case. However, it is possible that this counter is negative for a short period of time, due to the way UBIFS TNC code updates it. And I can observe the following warnings sometimes: shrink_slab: ubifs_shrinker+0x0/0x2b7 [ubifs] negative objects to delete nr=-8541616642706119788 This patch makes sure UBIFS never returns negative count of objects. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: stable@kernel.org
2011-06-01UBIFS: fix recovery broken by the previous recovery fixArtem Bityutskiy
Unfortunately, the recovery fix d1606a59b6be4ea392eabd40d1250aa1eeb19efb (UBIFS: fix extremely rare mount failure) broke recovery. This commit make UBIFS drop the last min. I/O unit in all journal heads, but this is needed only for the GC head. And this does not work for non-GC heads. For example, if suppose we have min. I/O units A and B, and A contains a valid node X, which was fsynced, and then a group of nodes Y which spans the rest of A and B. In this case we'll drop not only Y, but also X, which is obviously incorrect. This patch fixes the issue and additionally makes recovery to drop last min. I/O unit only for the GC head, and leave things as they have been for ages for the other heads - this is safer. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01UBIFS: amend ubifs_recover_leb interfaceArtem Bityutskiy
Instead of passing "grouped" parameter to 'ubifs_recover_leb()' which tells whether the nodes are grouped in the LEB to recover, pass the journal head number and let 'ubifs_recover_leb()' look at the journal head's 'grouped' flag. This patch is a preparation to a further fix where we'll need to know the journal head number for other purposes. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01UBIFS: introduce a "grouped" journal head flagArtem Bityutskiy
Journal heads are different in a way how UBIFS writes nodes there. All normal journal heads receive grouped nodes, while the GC journal heads receives ungrouped nodes. This patch adds a 'grouped' flag to 'struct ubifs_jhead' which describes this property. This patch is a preparation to a further recovery fix. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01UBIFS: supress false error messagesArtem Bityutskiy
Commit ab51afe05273741f72383529ef488aa1ea598ec6 was a good clean-up, but it introduced a regression - now UBIFS prints scary error messages during recovery on all corrupted nodes, even though the corruptions are expected (due to a power cut). This patch fixes the issue. Additionally fix a typo in a commentary introduced by the same commit. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01block: blkdev_get() should access ->bd_disk only after successTejun Heo
d4dc210f69 (block: don't block events on excl write for non-optical devices) added dereferencing of bdev->bd_disk to test GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE; however, bdev->bd_disk can be %NULL if open failed which can lead to an oops. Test the flag after testing open was successful, not before. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: David Miller <davem@davemloft.net> Tested-by: David Miller <davem@davemloft.net> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-30autofs4: bogus dentry_unhash() added in ->unlink()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-30vfs: shrink_dcache_parent before rmdir, dir renameSage Weil
The dentry_unhash push-down series missed that shink_dcache_parent needs to be called prior to rmdir or dir rename to clear DCACHE_REFERENCED and allow efficient dentry reclaim. Reported-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-30Revert "block: Remove extra discard_alignment from hd_struct."Jens Axboe
It was not a good idea to start dereferencing disk->queue from the fs sysfs strategy for displaying discard alignment. We ran into first a NULL pointer deref, and after fixing that we sometimes see unvalid disk->queue pointer values. Since discard is the only one of the bunch actually looking into the queue, just revert the change. This reverts commit 23ceb5b7719e9276d4fa72a3ecf94dd396755276. Conflicts: fs/partitions/check.c
2011-05-29Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6: eCryptfs: Remove ecryptfs_header_cache_2 eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose() eCryptfs: Return useful code from contains_ecryptfs_marker eCryptfs: Fix new inode race condition eCryptfs: Cleanup inode initialization code eCryptfs: Consolidate inode functions into inode.c
2011-05-29Merge branch 'pnfs-submit' of git://git.open-osd.org/linux-open-osdLinus Torvalds
* 'pnfs-submit' of git://git.open-osd.org/linux-open-osd: (32 commits) pnfs-obj: pg_test check for max_io_size NFSv4.1: define nfs_generic_pg_test NFSv4.1: use pnfs_generic_pg_test directly by layout driver NFSv4.1: change pg_test return type to bool NFSv4.1: unify pnfs_pageio_init functions pnfs-obj: objlayout_encode_layoutcommit implementation pnfs: encode_layoutcommit pnfs-obj: report errors and .encode_layoutreturn Implementation. pnfs: encode_layoutreturn pnfs: layoutret_on_setattr pnfs: layoutreturn pnfs-obj: osd raid engine read/write implementation pnfs: support for non-rpc layout drivers pnfs-obj: define per-inode private structure pnfs: alloc and free layout_hdr layoutdriver methods pnfs-obj: objio_osd device information retrieval and caching pnfs-obj: decode layout, alloc/free lseg pnfs-obj: pnfs_osd XDR client implementation pnfs-obj: pnfs_osd XDR definitions pnfs-obj: objlayoutdriver module skeleton ...
2011-05-29eCryptfs: Remove ecryptfs_header_cache_2Tyler Hicks
Now that ecryptfs_lookup_interpose() is no longer using ecryptfs_header_cache_2 to read in metadata, the kmem_cache can be removed and the ecryptfs_header_cache_1 kmem_cache can be renamed to ecryptfs_header_cache. Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-05-29eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose()Tyler Hicks
ecryptfs_lookup_interpose() has turned into spaghetti code over the years. This is an effort to clean it up. - Shorten overly descriptive variable names such as ecryptfs_dentry - Simplify gotos and error paths - Create helper function for reading plaintext i_size from metadata It also includes an optimization when reading i_size from the metadata. A complete page-sized kmem_cache_alloc() was being done to read in 16 bytes of metadata. The buffer for that is now statically declared. Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-05-29eCryptfs: Return useful code from contains_ecryptfs_markerTyler Hicks
Instead of having the calling functions translate the true/false return code to either 0 or -EINVAL, have contains_ecryptfs_marker() return 0 or -EINVAL so that the calling functions can just reuse the return code. Also, rename the function to ecryptfs_validate_marker() to avoid callers mistakenly thinking that it returns true/false codes. Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>