kernel/git/stable/linux.git/fs/gfs2/log.c, branch linux-3.0.y

GFS2: Resolve inode eviction and ail list interaction bug

2011-07-14T07:59:44+00:00

This patch contains a few misc fixes which resolve a recently reported issue. This patch has been a real team effort and has received a lot of testing. The first issue is that the ail lock needs to be held over a few more operations. The lock thats added into gfs2_releasepage() may possibly be a candidate for replacing with RCU at some future point, but at this stage we've gone for the obvious fix. The second issue is that gfs2_write_inode() can end up calling a glock recursively when called from gfs2_evict_inode() via the syncing code, so it needs a guard added. The third issue is that we either need to not truncate the metadata pages of inodes which have zero link count, but which we cannot deallocate due to them still being in use by other nodes, or we need to ensure that those pages have all made it through the journal and ail lists first. This patch takes the former approach, but the latter has also been tested and there is nothing to choose between them performance-wise. So again, we could revise that decision in the future. Also, the inode eviction process is now better documented. Signed-off-by: Steven Whitehouse Tested-by: Bob Peterson Tested-by: Abhijith Das Reported-by: Barry J. Marson Reported-by: David Teigland

GFS2: Wait properly when flushing the ail list

2011-05-21T18:21:07+00:00

The ail flush code has always relied upon log flushing to prevent it from spinning needlessly. This fixes it to wait on the last I/O request submitted (we don't need to wait for all of it) instead of either spinning with io_schedule or sleeping. As a result cpu usage of gfs2_logd is much reduced with certain workloads. Reported-by: Abhijith Das Tested-by: Abhijith Das Signed-off-by: Steven Whitehouse

GFS2: Fix ail list traversal

2011-05-03T10:48:07+00:00

In the recent patches to update the AIL list code, I managed to forget that the ail list lock got dropped, even though I added a comment specifically to remind myself :( Reported-by: Barry Marson Signed-off-by: Steven Whitehouse

GFS2: Add an AIL writeback tracepoint

2011-04-20T08:01:58+00:00

Add a tracepoint for monitoring writeback of the AIL. Signed-off-by: Steven Whitehouse

GFS2: Make writeback more responsive to system conditions

2011-04-20T08:01:37+00:00

This patch adds writeback_control to writing back the AIL list. This means that we can then take advantage of the information we get in ->write_inode() in order to set off some pre-emptive writeback. In addition, the AIL code is cleaned up a bit to make it a bit simpler to understand. There is still more which can usefully be done in this area, but this is a good start at least. Signed-off-by: Steven Whitehouse

GFS2: Use filemap_fdatawrite() to write back the AIL

2011-04-20T07:59:25+00:00

In order to ensure that the mapping stats (and thus the bdi) are correctly updated, this patch changes the AIL writeback to use the filemap_datawrite function. This helps prevent stalls in balance_dirty_pages() due to large amounts of dirty metadata when there is little or no dirty data around. Signed-off-by: Steven Whitehouse

Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block

2011-03-24T17:16:26+00:00

* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}

GFS2: Update to AIL list locking

2011-03-14T12:40:29+00:00

The previous patch missed a couple of places where the AIL list needed locking, so this fixes up those places, plus a comment is corrected too. Signed-off-by: Steven Whitehouse Cc: Dave Chinner

GFS2: introduce AIL lock

2011-03-11T11:52:25+00:00

The log lock is currently used to protect the AIL lists and the movements of buffers into and out of them. The lists are self contained and no log specific items outside the lists are accessed when starting or emptying the AIL lists. Hence the operation of the AIL does not require the protection of the log lock so split them out into a new AIL specific lock to reduce the amount of traffic on the log lock. This will also reduce the amount of serialisation that occurs when the gfs2_logd pushes on the AIL to move it forward. This reduces the impact of log pushing on sequential write throughput. Signed-off-by: Dave Chinner Signed-off-by: Steven Whitehouse

block: kill off REQ_UNPLUG

2011-03-10T07:52:27+00:00

With the plugging now being explicitly controlled by the submitter, callers need not pass down unplugging hints to the block layer. If they want to unplug, it's because they manually plugged on their own - in which case, they should just unplug at will. Signed-off-by: Jens Axboe