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  1. 19 8月, 2014 1 次提交
  3. 14 6月, 2014 1 次提交
    • E
      btrfs: fix use of uninit "ret" in end_extent_writepage() · 3e2426bd
      由 Eric Sandeen 提交于 
      If this condition in end_extent_writepage() is false:

	if (tree->ops && tree->ops->writepage_end_io_hook)

we will then test an uninitialized "ret" at:

	ret = ret < 0 ? ret : -EIO;

The test for ret is for the case where ->writepage_end_io_hook
failed, and we'd choose that ret as the error; but if
there is no ->writepage_end_io_hook, nothing sets ret.

Initializing ret to 0 should be sufficient; if
writepage_end_io_hook wasn't set, (!uptodate) means
non-zero err was passed in, so we choose -EIO in that case.
Signed-of-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NChris Mason <clm@fb.com>
      3e2426bd
  5. 13 6月, 2014 1 次提交
  7. 10 6月, 2014 6 次提交
    • C
      Btrfs: split up __extent_writepage to lower stack usage · 40f76580
      由 Chris Mason 提交于 
      __extent_writepage has two unrelated parts.  First it does the delayed
allocation dance and second it does the mapping and IO for the page
we're actually writing.

This splits it up into those two parts so the stack from one doesn't
impact the stack from the other.
Signed-off-by: NChris Mason <clm@fb.com>
      40f76580
    • C
      Btrfs: cut down stack usage in btree_write_cache_pages · 0e378df1
      由 Chris Mason 提交于 
      This adds noinline_for_stack to two helpers used by
btree_write_cache_pages.  It shaves us down from 424 bytes on the
stack to 280.
Signed-off-by: NChris Mason <clm@fb.com>
      0e378df1
    • C
      Btrfs: fix double free in find_lock_delalloc_range · 7d788742
      由 Chris Mason 提交于 
      We need to NULL the cached_state after freeing it, otherwise
we might free it again if find_delalloc_range doesn't find anything.
Signed-off-by: NChris Mason <clm@fb.com>
cc: stable@vger.kernel.org
      7d788742
    • J
      Btrfs: add sanity tests for new qgroup accounting code · faa2dbf0
      由 Josef Bacik 提交于 
      This exercises the various parts of the new qgroup accounting code.  We do some
basic stuff and do some things with the shared refs to make sure all that code
works.  I had to add a bunch of infrastructure because I needed to be able to
insert items into a fake tree without having to do all the hard work myself,
hopefully this will be usefull in the future.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>
      faa2dbf0
    • L
      Btrfs: mark mapping with error flag to report errors to userspace · 5dca6eea
      由 Liu Bo 提交于 
      According to commit 865ffef3
(fs: fix fsync() error reporting),
it's not stable to just check error pages because pages can be
truncated or invalidated, we should also mark mapping with error
flag so that a later fsync can catch the error.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>
      5dca6eea
    • F
      Btrfs: fix hang on error (such as ENOSPC) when writing extent pages · 61391d56
      由 Filipe Manana 提交于 
      When running low on available disk space and having several processes
doing buffered file IO, I got the following trace in dmesg:

[ 4202.720152] INFO: task kworker/u8:1:5450 blocked for more than 120 seconds.
[ 4202.720401]       Not tainted 3.13.0-fdm-btrfs-next-26+ #1
[ 4202.720596] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 4202.720874] kworker/u8:1    D 0000000000000001     0  5450      2 0x00000000
[ 4202.720904] Workqueue: btrfs-flush_delalloc normal_work_helper [btrfs]
[ 4202.720908]  ffff8801f62ddc38 0000000000000082 ffff880203ac2490 00000000001d3f40
[ 4202.720913]  ffff8801f62ddfd8 00000000001d3f40 ffff8800c4f0c920 ffff880203ac2490
[ 4202.720918]  00000000001d4a40 ffff88020fe85a40 ffff88020fe85ab8 0000000000000001
[ 4202.720922] Call Trace:
[ 4202.720931]  [<ffffffff816a3cb9>] schedule+0x29/0x70
[ 4202.720950]  [<ffffffffa01ec48d>] btrfs_start_ordered_extent+0x6d/0x110 [btrfs]
[ 4202.720956]  [<ffffffff8108e620>] ? bit_waitqueue+0xc0/0xc0
[ 4202.720972]  [<ffffffffa01ec559>] btrfs_run_ordered_extent_work+0x29/0x40 [btrfs]
[ 4202.720988]  [<ffffffffa0201987>] normal_work_helper+0x137/0x2c0 [btrfs]
[ 4202.720994]  [<ffffffff810680e5>] process_one_work+0x1f5/0x530
(...)
[ 4202.721027] 2 locks held by kworker/u8:1/5450:
[ 4202.721028]  #0:  (%s-%s){++++..}, at: [<ffffffff81068083>] process_one_work+0x193/0x530
[ 4202.721037]  #1:  ((&work->normal_work)){+.+...}, at: [<ffffffff81068083>] process_one_work+0x193/0x530
[ 4202.721054] INFO: task btrfs:7891 blocked for more than 120 seconds.
[ 4202.721258]       Not tainted 3.13.0-fdm-btrfs-next-26+ #1
[ 4202.721444] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 4202.721699] btrfs           D 0000000000000001     0  7891   7890 0x00000001
[ 4202.721704]  ffff88018c2119e8 0000000000000086 ffff8800a33d2490 00000000001d3f40
[ 4202.721710]  ffff88018c211fd8 00000000001d3f40 ffff8802144b0000 ffff8800a33d2490
[ 4202.721714]  ffff8800d8576640 ffff88020fe85bc0 ffff88020fe85bc8 7fffffffffffffff
[ 4202.721718] Call Trace:
[ 4202.721723]  [<ffffffff816a3cb9>] schedule+0x29/0x70
[ 4202.721727]  [<ffffffff816a2ebc>] schedule_timeout+0x1dc/0x270
[ 4202.721732]  [<ffffffff8109bd79>] ? mark_held_locks+0xb9/0x140
[ 4202.721736]  [<ffffffff816a90c0>] ? _raw_spin_unlock_irq+0x30/0x40
[ 4202.721740]  [<ffffffff8109bf0d>] ? trace_hardirqs_on_caller+0x10d/0x1d0
[ 4202.721744]  [<ffffffff816a488f>] wait_for_completion+0xdf/0x120
[ 4202.721749]  [<ffffffff8107fa90>] ? try_to_wake_up+0x310/0x310
[ 4202.721765]  [<ffffffffa01ebee4>] btrfs_wait_ordered_extents+0x1f4/0x280 [btrfs]
[ 4202.721781]  [<ffffffffa020526e>] btrfs_mksubvol.isra.62+0x30e/0x5a0 [btrfs]
[ 4202.721786]  [<ffffffff8108e620>] ? bit_waitqueue+0xc0/0xc0
[ 4202.721799]  [<ffffffffa02056a9>] btrfs_ioctl_snap_create_transid+0x1a9/0x1b0 [btrfs]
[ 4202.721813]  [<ffffffffa020583a>] btrfs_ioctl_snap_create_v2+0x10a/0x170 [btrfs]
(...)

It turns out that extent_io.c:__extent_writepage(), which ends up being called
through filemap_fdatawrite_range() in btrfs_start_ordered_extent(), was getting
-ENOSPC when calling the fill_delalloc callback. In this situation, it returned
without the writepage_end_io_hook callback (inode.c:btrfs_writepage_end_io_hook)
ever being called for the respective page, which prevents the ordered extent's
bytes_left count from ever reaching 0, and therefore a finish_ordered_fn work
is never queued into the endio_write_workers queue. This makes the task that
called btrfs_start_ordered_extent() hang forever on the wait queue of the ordered
extent.

This is fairly easy to reproduce using a small filesystem and fsstress on
a quad core vm:

    mkfs.btrfs -f -b `expr 2100 \* 1024 \* 1024` /dev/sdd
    mount /dev/sdd /mnt

    fsstress -p 6 -d /mnt -n 100000 -x \
        "btrfs subvolume snapshot -r /mnt /mnt/mysnap" \
	    -f allocsp=0 \
	    -f bulkstat=0 \
	    -f bulkstat1=0 \
	    -f chown=0 \
	    -f creat=1 \
	    -f dread=0 \
	    -f dwrite=0 \
	    -f fallocate=1 \
	    -f fdatasync=0 \
	    -f fiemap=0 \
	    -f freesp=0 \
	    -f fsync=0 \
	    -f getattr=0 \
	    -f getdents=0 \
	    -f link=0 \
	    -f mkdir=0 \
	    -f mknod=0 \
	    -f punch=1 \
	    -f read=0 \
	    -f readlink=0 \
	    -f rename=0 \
	    -f resvsp=0 \
	    -f rmdir=0 \
	    -f setxattr=0 \
	    -f stat=0 \
	    -f symlink=0 \
	    -f sync=0 \
	    -f truncate=1 \
	    -f unlink=0 \
	    -f unresvsp=0 \
	    -f write=4

So just ensure that if an error happens while writing the extent page
we call the writepage_end_io_hook callback. Also make it return the
error code and ensure the caller (extent_write_cache_pages) processes
all pages in the page vector even if an error happens only for some
of them, so that ordered extents end up released.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>
      61391d56
  9. 05 6月, 2014 1 次提交
    • M
      mm: non-atomically mark page accessed during page cache allocation where possible · 2457aec6
      由 Mel Gorman 提交于 
      aops->write_begin may allocate a new page and make it visible only to have
mark_page_accessed called almost immediately after.  Once the page is
visible the atomic operations are necessary which is noticable overhead
when writing to an in-memory filesystem like tmpfs but should also be
noticable with fast storage.  The objective of the patch is to initialse
the accessed information with non-atomic operations before the page is
visible.

The bulk of filesystems directly or indirectly use
grab_cache_page_write_begin or find_or_create_page for the initial
allocation of a page cache page.  This patch adds an init_page_accessed()
helper which behaves like the first call to mark_page_accessed() but may
called before the page is visible and can be done non-atomically.

The primary APIs of concern in this care are the following and are used
by most filesystems.

	find_get_page
	find_lock_page
	find_or_create_page
	grab_cache_page_nowait
	grab_cache_page_write_begin

All of them are very similar in detail to the patch creates a core helper
pagecache_get_page() which takes a flags parameter that affects its
behavior such as whether the page should be marked accessed or not.  Then
old API is preserved but is basically a thin wrapper around this core
function.

Each of the filesystems are then updated to avoid calling
mark_page_accessed when it is known that the VM interfaces have already
done the job.  There is a slight snag in that the timing of the
mark_page_accessed() has now changed so in rare cases it's possible a page
gets to the end of the LRU as PageReferenced where as previously it might
have been repromoted.  This is expected to be rare but it's worth the
filesystem people thinking about it in case they see a problem with the
timing change.  It is also the case that some filesystems may be marking
pages accessed that previously did not but it makes sense that filesystems
have consistent behaviour in this regard.

The test case used to evaulate this is a simple dd of a large file done
multiple times with the file deleted on each iterations.  The size of the
file is 1/10th physical memory to avoid dirty page balancing.  In the
async case it will be possible that the workload completes without even
hitting the disk and will have variable results but highlight the impact
of mark_page_accessed for async IO.  The sync results are expected to be
more stable.  The exception is tmpfs where the normal case is for the "IO"
to not hit the disk.

The test machine was single socket and UMA to avoid any scheduling or NUMA
artifacts.  Throughput and wall times are presented for sync IO, only wall
times are shown for async as the granularity reported by dd and the
variability is unsuitable for comparison.  As async results were variable
do to writback timings, I'm only reporting the maximum figures.  The sync
results were stable enough to make the mean and stddev uninteresting.

The performance results are reported based on a run with no profiling.
Profile data is based on a separate run with oprofile running.

async dd
                                    3.15.0-rc3            3.15.0-rc3
                                       vanilla           accessed-v2
ext3    Max      elapsed     13.9900 (  0.00%)     11.5900 ( 17.16%)
tmpfs	Max      elapsed      0.5100 (  0.00%)      0.4900 (  3.92%)
btrfs   Max      elapsed     12.8100 (  0.00%)     12.7800 (  0.23%)
ext4	Max      elapsed     18.6000 (  0.00%)     13.3400 ( 28.28%)
xfs	Max      elapsed     12.5600 (  0.00%)      2.0900 ( 83.36%)

The XFS figure is a bit strange as it managed to avoid a worst case by
sheer luck but the average figures looked reasonable.

        samples percentage
ext3       86107    0.9783  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
ext3       23833    0.2710  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
ext3        5036    0.0573  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
ext4       64566    0.8961  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
ext4        5322    0.0713  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
ext4        2869    0.0384  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
xfs        62126    1.7675  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
xfs         1904    0.0554  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
xfs          103    0.0030  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
btrfs      10655    0.1338  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
btrfs       2020    0.0273  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
btrfs        587    0.0079  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
tmpfs      59562    3.2628  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
tmpfs       1210    0.0696  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
tmpfs         94    0.0054  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed

[akpm@linux-foundation.org: don't run init_page_accessed() against an uninitialised pointer]
Signed-off-by: NMel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Tested-by: NPrabhakar Lad <prabhakar.csengg@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2457aec6
  11. 18 4月, 2014 1 次提交
  13. 08 4月, 2014 1 次提交
  15. 07 4月, 2014 1 次提交
    • J
      Btrfs: don't clear uptodate if the eb is under IO · a26e8c9f
      由 Josef Bacik 提交于 
      So I have an awful exercise script that will run snapshot, balance and
send/receive in parallel.  This sometimes would crash spectacularly and when it
came back up the fs would be completely hosed.  Turns out this is because of a
bad interaction of balance and send/receive.  Send will hold onto its entire
path for the whole send, but its blocks could get relocated out from underneath
it, and because it doesn't old tree locks theres nothing to keep this from
happening.  So it will go to read in a slot with an old transid, and we could
have re-allocated this block for something else and it could have a completely
different transid.  But because we think it is invalid we clear uptodate and
re-read in the block.  If we do this before we actually write out the new block
we could write back stale data to the fs, and boom we're screwed.

Now we definitely need to fix this disconnect between send and balance, but we
really really need to not allow ourselves to accidently read in stale data over
new data.  So make sure we check if the extent buffer is not under io before
clearing uptodate, this will kick back EIO to the caller instead of reading in
stale data and keep us from corrupting the fs.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>
      a26e8c9f
  17. 11 3月, 2014 2 次提交
  19. 29 1月, 2014 8 次提交
  21. 25 11月, 2013 1 次提交
  23. 24 11月, 2013 3 次提交
    • K
      block: Abstract out bvec iterator · 4f024f37
      由 Kent Overstreet 提交于 
      Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchand@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Peng Tao <tao.peng@emc.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Mel Gorman <mgorman@suse.de>6
      4f024f37
    • K
      block: Convert various code to bio_for_each_segment() · 2c30c71b
      由 Kent Overstreet 提交于 
      With immutable biovecs we don't want code accessing bi_io_vec directly -
the uses this patch changes weren't incorrect since they all own the
bio, but it makes the code harder to audit for no good reason - also,
this will help with multipage bvecs later.
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
      2c30c71b
    • K
      block: submit_bio_wait() conversions · 33879d45
      由 Kent Overstreet 提交于 
      It was being open coded in a few places.
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Chris Mason <chris.mason@fusionio.com>
Acked-by: NNeilBrown <neilb@suse.de>
      33879d45
  25. 21 11月, 2013 1 次提交
  27. 12 11月, 2013 7 次提交
  29. 11 10月, 2013 1 次提交
    • J
      Btrfs: limit delalloc pages outside of find_delalloc_range · 7bf811a5
      由 Josef Bacik 提交于 
      Liu fixed part of this problem and unfortunately I steered him in slightly the
wrong direction and so didn't completely fix the problem.  The problem is we
limit the size of the delalloc range we are looking for to max bytes and then we
try to lock that range.  If we fail to lock the pages in that range we will
shrink the max bytes to a single page and re loop.  However if our first page is
inside of the delalloc range then we will end up limiting the end of the range
to a period before our first page.  This is illustrated below

[0 -------- delalloc range --------- 256mb]
                                  [page]

So find_delalloc_range will return with delalloc_start as 0 and end as 128mb,
and then we will notice that delalloc_start < *start and adjust it up, but not
adjust delalloc_end up, so things go sideways.  To fix this we need to not limit
the max bytes in find_delalloc_range, but in find_lock_delalloc_range and that
way we don't end up with this confusion.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>
      7bf811a5
  31. 05 10月, 2013 2 次提交
    • D
      btrfs: Fix crash due to not allocating integrity data for a bioset · b208c2f7
      由 Darrick J. Wong 提交于 
      When btrfs creates a bioset, we must also allocate the integrity data pool.
Otherwise btrfs will crash when it tries to submit a bio to a checksumming
disk:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
 IP: [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150
 PGD 2305e4067 PUD 23063d067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP
 Modules linked in: btrfs scsi_debug xfs ext4 jbd2 ext3 jbd mbcache
sch_fq_codel eeprom lpc_ich mfd_core nfsd exportfs auth_rpcgss af_packet
raid6_pq xor zlib_deflate libcrc32c [last unloaded: scsi_debug]
 CPU: 1 PID: 4486 Comm: mount Not tainted 3.12.0-rc1-mcsum #2
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 task: ffff8802451c9720 ti: ffff880230698000 task.ti: ffff880230698000
 RIP: 0010:[<ffffffff8111e28a>]  [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150
 RSP: 0018:ffff880230699688  EFLAGS: 00010286
 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000005f8445
 RDX: 0000000000000001 RSI: 0000000000000010 RDI: 0000000000000000
 RBP: ffff8802306996f8 R08: 0000000000011200 R09: 0000000000000008
 R10: 0000000000000020 R11: ffff88009d6e8000 R12: 0000000000011210
 R13: 0000000000000030 R14: ffff8802306996b8 R15: ffff8802451c9720
 FS:  00007f25b8a16800(0000) GS:ffff88024fc80000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 0000000000000018 CR3: 0000000230576000 CR4: 00000000000007e0
 Stack:
  ffff8802451c9720 0000000000000002 ffffffff81a97100 0000000000281250
  ffffffff81a96480 ffff88024fc99150 ffff880228d18200 0000000000000000
  0000000000000000 0000000000000040 ffff880230e8c2e8 ffff8802459dc900
 Call Trace:
  [<ffffffff811b2208>] bio_integrity_alloc+0x48/0x1b0
  [<ffffffff811b26fc>] bio_integrity_prep+0xac/0x360
  [<ffffffff8111e298>] ? mempool_alloc+0x58/0x150
  [<ffffffffa03e8041>] ? alloc_extent_state+0x31/0x110 [btrfs]
  [<ffffffff81241579>] blk_queue_bio+0x1c9/0x460
  [<ffffffff8123e58a>] generic_make_request+0xca/0x100
  [<ffffffff8123e639>] submit_bio+0x79/0x160
  [<ffffffffa03f865e>] btrfs_map_bio+0x48e/0x5b0 [btrfs]
  [<ffffffffa03c821a>] btree_submit_bio_hook+0xda/0x110 [btrfs]
  [<ffffffffa03e7eba>] submit_one_bio+0x6a/0xa0 [btrfs]
  [<ffffffffa03ef450>] read_extent_buffer_pages+0x250/0x310 [btrfs]
  [<ffffffff8125eef6>] ? __radix_tree_preload+0x66/0xf0
  [<ffffffff8125f1c5>] ? radix_tree_insert+0x95/0x260
  [<ffffffffa03c66f6>] btree_read_extent_buffer_pages.constprop.128+0xb6/0x120
[btrfs]
  [<ffffffffa03c8c1a>] read_tree_block+0x3a/0x60 [btrfs]
  [<ffffffffa03caefd>] open_ctree+0x139d/0x2030 [btrfs]
  [<ffffffffa03a282a>] btrfs_mount+0x53a/0x7d0 [btrfs]
  [<ffffffff8113ab0b>] ? pcpu_alloc+0x8eb/0x9f0
  [<ffffffff81167305>] ? __kmalloc_track_caller+0x35/0x1e0
  [<ffffffff81176ba0>] mount_fs+0x20/0xd0
  [<ffffffff81191096>] vfs_kern_mount+0x76/0x120
  [<ffffffff81193320>] do_mount+0x200/0xa40
  [<ffffffff81135cdb>] ? strndup_user+0x5b/0x80
  [<ffffffff81193bf0>] SyS_mount+0x90/0xe0
  [<ffffffff8156d31d>] system_call_fastpath+0x1a/0x1f
 Code: 4c 8d 75 a8 4c 89 6d e8 45 89 e0 4c 8d 6f 30 48 89 5d d8 41 83 e0 af 48
89 fb 49 83 c6 18 4c 89 7d f8 65 4c 8b 3c 25 c0 b8 00 00 <48> 8b 73 18 44 89 c7
44 89 45 98 ff 53 20 48 85 c0 48 89 c2 74
 RIP  [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150
  RSP <ffff880230699688>
 CR2: 0000000000000018
 ---[ end trace 7a96042017ed21e2 ]---
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>
      b208c2f7
    • L
      Btrfs: fix crash of compressed writes · 385fe0be
      由 Liu Bo 提交于 
      The crash[1] is found by xfstests/generic/208 with "-o compress",
it's not reproduced everytime, but it does panic.

The bug is quite interesting, it's actually introduced by a recent commit
(573aecaf,
Btrfs: actually limit the size of delalloc range).

Btrfs implements delay allocation, so during writeback, we
(1) get a page A and lock it
(2) search the state tree for delalloc bytes and lock all pages within the range
(3) process the delalloc range, including find disk space and create
    ordered extent and so on.
(4) submit the page A.

It runs well in normal cases, but if we're in a racy case, eg.
buffered compressed writes and aio-dio writes,
sometimes we may fail to lock all pages in the 'delalloc' range,
in which case, we need to fall back to search the state tree again with
a smaller range limit(max_bytes = PAGE_CACHE_SIZE - offset).

The mentioned commit has a side effect, that is, in the fallback case,
we can find delalloc bytes before the index of the page we already have locked,
so we're in the case of (delalloc_end <= *start) and return with (found > 0).

This ends with not locking delalloc pages but making ->writepage still
process them, and the crash happens.

This fixes it by just thinking that we find nothing and returning to caller
as the caller knows how to deal with it properly.

[1]:
------------[ cut here ]------------
kernel BUG at mm/page-writeback.c:2170!
[...]
CPU: 2 PID: 11755 Comm: btrfs-delalloc- Tainted: G           O 3.11.0+ #8
[...]
RIP: 0010:[<ffffffff810f5093>]  [<ffffffff810f5093>] clear_page_dirty_for_io+0x1e/0x83
[...]
[ 4934.248731] Stack:
[ 4934.248731]  ffff8801477e5dc8 ffffea00049b9f00 ffff8801869f9ce8 ffffffffa02b841a
[ 4934.248731]  0000000000000000 0000000000000000 0000000000000fff 0000000000000620
[ 4934.248731]  ffff88018db59c78 ffffea0005da8d40 ffffffffa02ff860 00000001810016c0
[ 4934.248731] Call Trace:
[ 4934.248731]  [<ffffffffa02b841a>] extent_range_clear_dirty_for_io+0xcf/0xf5 [btrfs]
[ 4934.248731]  [<ffffffffa02a8889>] compress_file_range+0x1dc/0x4cb [btrfs]
[ 4934.248731]  [<ffffffff8104f7af>] ? detach_if_pending+0x22/0x4b
[ 4934.248731]  [<ffffffffa02a8bad>] async_cow_start+0x35/0x53 [btrfs]
[ 4934.248731]  [<ffffffffa02c694b>] worker_loop+0x14b/0x48c [btrfs]
[ 4934.248731]  [<ffffffffa02c6800>] ? btrfs_queue_worker+0x25c/0x25c [btrfs]
[ 4934.248731]  [<ffffffff810608f5>] kthread+0x8d/0x95
[ 4934.248731]  [<ffffffff81060868>] ? kthread_freezable_should_stop+0x43/0x43
[ 4934.248731]  [<ffffffff814fe09c>] ret_from_fork+0x7c/0xb0
[ 4934.248731]  [<ffffffff81060868>] ? kthread_freezable_should_stop+0x43/0x43
[ 4934.248731] Code: ff 85 c0 0f 94 c0 0f b6 c0 59 5b 5d c3 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 89 fb e8 2c de 00 00 49 89 c4 48 8b 03 a8 01 75 02 <0f> 0b 4d 85 e4 74 52 49 8b 84 24 80 00 00 00 f6 40 20 01 75 44
[ 4934.248731] RIP  [<ffffffff810f5093>] clear_page_dirty_for_io+0x1e/0x83
[ 4934.248731]  RSP <ffff8801869f9c48>
[ 4934.280307] ---[ end trace 36f06d3f8750236a ]---
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
      385fe0be
  33. 21 9月, 2013 1 次提交
    • J
      Btrfs: actually limit the size of delalloc range · 573aecaf
      由 Josef Bacik 提交于 
      So forever we have had this thing to limit the amount of delalloc pages we'll
setup to be written out to 128mb.  This is because we have to lock all the pages
in this range, so anything above this gets a bit unweildly, and also without a
limit we'll happily allocate gigantic chunks of disk space.  Turns out our check
for this wasn't quite right, we wouldn't actually limit the chunk we wanted to
write out, we'd just stop looking for more space after we went over the limit.
So if you do a giant 20gb dd on my box with lots of ram I could get 2gig
extents.  This is fine normally, except when you go to relocate these extents
and we can't find enough space to relocate these moster extents, since we have
to be able to allocate exactly the same sized extent to move it around.  So fix
this by actually enforcing the limit.  With this patch I'm no longer seeing
giant 1.5gb extents.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>
      573aecaf
  35. 01 9月, 2013 1 次提交