Two reasons:
- btrfs_end_transaction_dmeta() is the same as btrfs_end_transaction_throttle()
so it is unnecessary.
- All the delayed items should be dealt in the current transaction, so the
workers should not commit the transaction, instead, deal with the delayed
items as many as possible.
So we can remove btrfs_end_transaction_dmeta()
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
- move the condition check for wait into a function
- use wait_event_interruptible instead of prepare-schedule-finish process
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
If the number of the delayed items is greater than the upper limit, we will
try to flush all the delayed items. After that, it is unnecessary to run
them again because they are being dealt with by the wokers or the number of
them is less than the lower limit.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Before applying the patch
commit de3cb945db
title: Btrfs: improve the delayed inode throttling
We need requeue the async work after the current work was done, it
introduced a deadlock problem. So we wrote the code that this patch
removes to avoid the above problem. But after applying the above
patch, the deadlock problem didn't exist. So we should remove that
fix code.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Convert all applicable cases of printk and pr_* to the btrfs_* macros.
Fix all uses of the BTRFS prefix.
Signed-off-by: Frank Holton <fholton@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
While running the test btrfs/004 from xfstests in a loop, it failed
about 1 time out of 20 runs in my desktop. The failure happened in
the backref walking part of the test, and the test's error message was
like this:
btrfs/004 93s ... [failed, exit status 1] - output mismatch (see /home/fdmanana/git/hub/xfstests_2/results//btrfs/004.out.bad)
--- tests/btrfs/004.out 2013-11-26 18:25:29.263333714 +0000
+++ /home/fdmanana/git/hub/xfstests_2/results//btrfs/004.out.bad 2013-12-10 15:25:10.327518516 +0000
@@ -1,3 +1,8 @@
QA output created by 004
*** test backref walking
-*** done
+unexpected output from
+ /home/fdmanana/git/hub/btrfs-progs/btrfs inspect-internal logical-resolve -P 141512704 /home/fdmanana/btrfs-tests/scratch_1
+expected inum: 405, expected address: 454656, file: /home/fdmanana/btrfs-tests/scratch_1/snap1/p0/d6/d3d/d156/fce, got:
+
...
(Run 'diff -u tests/btrfs/004.out /home/fdmanana/git/hub/xfstests_2/results//btrfs/004.out.bad' to see the entire diff)
Ran: btrfs/004
Failures: btrfs/004
Failed 1 of 1 tests
But immediately after the test finished, the btrfs inspect-internal command
returned the expected output:
$ btrfs inspect-internal logical-resolve -P 141512704 /home/fdmanana/btrfs-tests/scratch_1
inode 405 offset 454656 root 258
inode 405 offset 454656 root 5
It turned out this was because the btrfs_search_old_slot() calls performed
during backref walking (backref.c:__resolve_indirect_ref) were not finding
anything. The reason for this turned out to be that the tree mod logging
code was not logging some node multi-step operations atomically, therefore
btrfs_search_old_slot() callers iterated often over an incomplete tree that
wasn't fully consistent with any tree state from the past. Besides missing
items, this often (but not always) resulted in -EIO errors during old slot
searches, reported in dmesg like this:
[ 4299.933936] ------------[ cut here ]------------
[ 4299.933949] WARNING: CPU: 0 PID: 23190 at fs/btrfs/ctree.c:1343 btrfs_search_old_slot+0x57b/0xab0 [btrfs]()
[ 4299.933950] Modules linked in: btrfs raid6_pq xor pci_stub vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) bnep rfcomm bluetooth parport_pc ppdev binfmt_misc joydev snd_hda_codec_h
[ 4299.933977] CPU: 0 PID: 23190 Comm: btrfs Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70
[ 4299.933978] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./Z77 Pro4, BIOS P1.50 09/04/2012
[ 4299.933979] 000000000000053f ffff8806f3fd98f8 ffffffff8176d284 0000000000000007
[ 4299.933982] 0000000000000000 ffff8806f3fd9938 ffffffff8104a81c ffff880659c64b70
[ 4299.933984] ffff880659c643d0 ffff8806599233d8 ffff880701e2e938 0000160000000000
[ 4299.933987] Call Trace:
[ 4299.933991] [<ffffffff8176d284>] dump_stack+0x55/0x76
[ 4299.933994] [<ffffffff8104a81c>] warn_slowpath_common+0x8c/0xc0
[ 4299.933997] [<ffffffff8104a86a>] warn_slowpath_null+0x1a/0x20
[ 4299.934003] [<ffffffffa065d3bb>] btrfs_search_old_slot+0x57b/0xab0 [btrfs]
[ 4299.934005] [<ffffffff81775f3b>] ? _raw_read_unlock+0x2b/0x50
[ 4299.934010] [<ffffffffa0655001>] ? __tree_mod_log_search+0x81/0xc0 [btrfs]
[ 4299.934019] [<ffffffffa06dd9b0>] __resolve_indirect_refs+0x130/0x5f0 [btrfs]
[ 4299.934027] [<ffffffffa06a21f1>] ? free_extent_buffer+0x61/0xc0 [btrfs]
[ 4299.934034] [<ffffffffa06de39c>] find_parent_nodes+0x1fc/0xe40 [btrfs]
[ 4299.934042] [<ffffffffa06b13e0>] ? defrag_lookup_extent+0xe0/0xe0 [btrfs]
[ 4299.934048] [<ffffffffa06b13e0>] ? defrag_lookup_extent+0xe0/0xe0 [btrfs]
[ 4299.934056] [<ffffffffa06df980>] iterate_extent_inodes+0xe0/0x250 [btrfs]
[ 4299.934058] [<ffffffff817762db>] ? _raw_spin_unlock+0x2b/0x50
[ 4299.934065] [<ffffffffa06dfb82>] iterate_inodes_from_logical+0x92/0xb0 [btrfs]
[ 4299.934071] [<ffffffffa06b13e0>] ? defrag_lookup_extent+0xe0/0xe0 [btrfs]
[ 4299.934078] [<ffffffffa06b7015>] btrfs_ioctl+0xf65/0x1f60 [btrfs]
[ 4299.934080] [<ffffffff811658b8>] ? handle_mm_fault+0x278/0xb00
[ 4299.934083] [<ffffffff81075563>] ? up_read+0x23/0x40
[ 4299.934085] [<ffffffff8177a41c>] ? __do_page_fault+0x20c/0x5a0
[ 4299.934088] [<ffffffff811b2946>] do_vfs_ioctl+0x96/0x570
[ 4299.934090] [<ffffffff81776e23>] ? error_sti+0x5/0x6
[ 4299.934093] [<ffffffff810b71e8>] ? trace_hardirqs_off_caller+0x28/0xd0
[ 4299.934096] [<ffffffff81776a09>] ? retint_swapgs+0xe/0x13
[ 4299.934098] [<ffffffff811b2eb1>] SyS_ioctl+0x91/0xb0
[ 4299.934100] [<ffffffff813eecde>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 4299.934102] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
[ 4299.934102] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
[ 4299.934104] ---[ end trace 48f0cfc902491414 ]---
[ 4299.934378] btrfs bad fsid on block 0
These tree mod log operations that must be performed atomically, tree_mod_log_free_eb,
tree_mod_log_eb_copy, tree_mod_log_insert_root and tree_mod_log_insert_move, used to
be performed atomically before the following commit:
c8cc634165
(Btrfs: stop using GFP_ATOMIC for the tree mod log allocations)
That change removed the atomicity of such operations. This patch restores the
atomicity while still not doing the GFP_ATOMIC allocations of tree_mod_elem
structures, so it has to do the allocations using GFP_NOFS before acquiring
the mod log lock.
This issue has been experienced by several users recently, such as for example:
http://www.spinics.net/lists/linux-btrfs/msg28574.html
After running the btrfs/004 test for 679 consecutive iterations with this
patch applied, I didn't ran into the issue anymore.
Cc: stable@vger.kernel.org
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Warn if the balance goes below zero, which appears to be unlikely
though. Otherwise cleans up the code a bit.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Since daivd did the work that force us to use readonly snapshot,
we can safely remove transaction protection from btrfs send.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We met the following oops when doing space balance:
kobject (ffff88081b590278): tried to init an initialized object, something is seriously wrong.
...
Call Trace:
[<ffffffff81937262>] dump_stack+0x49/0x5f
[<ffffffff8137d259>] kobject_init+0x89/0xa0
[<ffffffff8137d36a>] kobject_init_and_add+0x2a/0x70
[<ffffffffa009bd79>] ? clear_extent_bit+0x199/0x470 [btrfs]
[<ffffffffa005e82c>] __link_block_group+0xfc/0x120 [btrfs]
[<ffffffffa006b9db>] btrfs_make_block_group+0x24b/0x370 [btrfs]
[<ffffffffa00a899b>] __btrfs_alloc_chunk+0x54b/0x7e0 [btrfs]
[<ffffffffa00a8c6f>] btrfs_alloc_chunk+0x3f/0x50 [btrfs]
[<ffffffffa0060123>] do_chunk_alloc+0x363/0x440 [btrfs]
[<ffffffffa00633d4>] btrfs_check_data_free_space+0x104/0x310 [btrfs]
[<ffffffffa0069f4d>] btrfs_write_dirty_block_groups+0x48d/0x600 [btrfs]
[<ffffffffa007aad4>] commit_cowonly_roots+0x184/0x250 [btrfs]
...
Steps to reproduce:
# mkfs.btrfs -f <dev>
# mount -o nospace_cache <dev> <mnt>
# btrfs balance start <mnt>
# dd if=/dev/zero of=<mnt>/tmpfile bs=1M count=1
The reason of this problem is that we initialized the raid kobject when we added
a block group into a empty raid list. As we know, when we mounted a btrfs filesystem,
the raid list was empty, we would initialize the raid kobject when we added the first
block group. But if there was not data stored in the block group, the block group
would be freed when doing balance, and the raid list would be empty. And then if we
allocated a new block group and added it into the raid list, we would initialize
the raid kobject again, the oops happened.
Fix this problem by initializing the raid kobject just when mounting the fs.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reported-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
All the subvolues that are involved in send must be read-only during the
whole operation. The ioctl SUBVOL_SETFLAGS could be used to change the
status to read-write and the result of send stream is undefined if the
data change unexpectedly.
Fix that by adding a refcount for all involved roots and verify that
there's no send in progress during SUBVOL_SETFLAGS ioctl call that does
read-only -> read-write transition.
We need refcounts because there are no restrictions on number of send
parallel operations currently run on a single subvolume, be it source,
parent or one of the multiple clone sources.
Kernel is silent when the RO checks fail and returns EPERM. The same set
of checks is done already in userspace before send starts.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Unused since ed2590953b
"Btrfs: stop using vfs_read in send".
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Remove ifdefed code:
- tlv_put for 8, 16 and 32, add a generic tempalte if needed in future
- tlv_put_timespec - the btrfs_timespec fields are used
- fs_path_remove obsoleted long ago
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
While running btrfs/004 from xfstests, after 503 iterations, dmesg reported
a deadlock between tasks iterating inode refs and tasks running delayed inodes
(during a transaction commit).
It turns out that iterating inode refs implies doing one tree search and
release all nodes in the path except the leaf node, and then passing that
leaf node to btrfs_ref_to_path(), which in turn does another tree search
without releasing the lock on the leaf node it received as parameter.
This is a problem when other task wants to write to the btree as well and
ends up updating the leaf that is read locked - the writer task locks the
parent of the leaf and then blocks waiting for the leaf's lock to be
released - at the same time, the task executing btrfs_ref_to_path()
does a second tree search, without releasing the lock on the first leaf,
and wants to access a leaf (the same or another one) that is a child of
the same parent, resulting in a deadlock.
The trace reported by lockdep follows.
[84314.936373] INFO: task fsstress:11930 blocked for more than 120 seconds.
[84314.936381] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70
[84314.936383] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[84314.936386] fsstress D ffff8806e1bf8000 0 11930 11926 0x00000000
[84314.936393] ffff8804d6d89b78 0000000000000046 ffff8804d6d89b18 ffffffff810bd8bd
[84314.936399] ffff8806e1bf8000 ffff8804d6d89fd8 ffff8804d6d89fd8 ffff8804d6d89fd8
[84314.936405] ffff880806308000 ffff8806e1bf8000 ffff8804d6d89c08 ffff8804deb8f190
[84314.936410] Call Trace:
[84314.936421] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10
[84314.936428] [<ffffffff81774269>] schedule+0x29/0x70
[84314.936451] [<ffffffffa0715bf5>] btrfs_tree_lock+0x75/0x270 [btrfs]
[84314.936457] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60
[84314.936470] [<ffffffffa06ba231>] btrfs_search_slot+0x7f1/0x930 [btrfs]
[84314.936489] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs]
[84314.936504] [<ffffffffa06d2e1f>] btrfs_lookup_inode+0x2f/0xa0 [btrfs]
[84314.936510] [<ffffffff810bd6ef>] ? trace_hardirqs_on_caller+0x1f/0x1e0
[84314.936528] [<ffffffffa073173c>] __btrfs_update_delayed_inode+0x4c/0x1d0 [btrfs]
[84314.936543] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs]
[84314.936558] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs]
[84314.936573] [<ffffffffa0731c82>] __btrfs_run_delayed_items+0x192/0x1e0 [btrfs]
[84314.936589] [<ffffffffa0731d03>] btrfs_run_delayed_items+0x13/0x20 [btrfs]
[84314.936604] [<ffffffffa06dbcd4>] btrfs_flush_all_pending_stuffs+0x24/0x80 [btrfs]
[84314.936620] [<ffffffffa06ddc13>] btrfs_commit_transaction+0x223/0xa20 [btrfs]
[84314.936630] [<ffffffffa06ae5ae>] btrfs_sync_fs+0x6e/0x110 [btrfs]
[84314.936635] [<ffffffff811d0b50>] ? __sync_filesystem+0x60/0x60
[84314.936639] [<ffffffff811d0b50>] ? __sync_filesystem+0x60/0x60
[84314.936643] [<ffffffff811d0b70>] sync_fs_one_sb+0x20/0x30
[84314.936648] [<ffffffff811a3541>] iterate_supers+0xf1/0x100
[84314.936652] [<ffffffff811d0c45>] sys_sync+0x55/0x90
[84314.936658] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
[84314.936660] INFO: lockdep is turned off.
[84314.936663] INFO: task btrfs:11955 blocked for more than 120 seconds.
[84314.936666] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70
[84314.936668] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[84314.936670] btrfs D ffff880541729a88 0 11955 11608 0x00000000
[84314.936674] ffff880541729a38 0000000000000046 ffff8805417299d8 ffffffff810bd8bd
[84314.936680] ffff88075430c8a0 ffff880541729fd8 ffff880541729fd8 ffff880541729fd8
[84314.936685] ffffffff81c104e0 ffff88075430c8a0 ffff8804de8b00b8 ffff8804de8b0000
[84314.936690] Call Trace:
[84314.936695] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10
[84314.936700] [<ffffffff81774269>] schedule+0x29/0x70
[84314.936717] [<ffffffffa0715815>] btrfs_tree_read_lock+0xd5/0x140 [btrfs]
[84314.936721] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60
[84314.936733] [<ffffffffa06ba201>] btrfs_search_slot+0x7c1/0x930 [btrfs]
[84314.936746] [<ffffffffa06bd505>] btrfs_find_item+0x55/0x160 [btrfs]
[84314.936763] [<ffffffffa06ff689>] ? free_extent_buffer+0x49/0xc0 [btrfs]
[84314.936780] [<ffffffffa073c9ca>] btrfs_ref_to_path+0xba/0x1e0 [btrfs]
[84314.936797] [<ffffffffa06f9719>] ? release_extent_buffer+0xb9/0xe0 [btrfs]
[84314.936813] [<ffffffffa06ff689>] ? free_extent_buffer+0x49/0xc0 [btrfs]
[84314.936830] [<ffffffffa073cb50>] inode_to_path+0x60/0xd0 [btrfs]
[84314.936846] [<ffffffffa073d365>] paths_from_inode+0x115/0x3c0 [btrfs]
[84314.936851] [<ffffffff8118dd44>] ? kmem_cache_alloc_trace+0x114/0x200
[84314.936868] [<ffffffffa0714494>] btrfs_ioctl+0xf14/0x2030 [btrfs]
[84314.936873] [<ffffffff817762db>] ? _raw_spin_unlock+0x2b/0x50
[84314.936877] [<ffffffff8116598f>] ? handle_mm_fault+0x34f/0xb00
[84314.936882] [<ffffffff81075563>] ? up_read+0x23/0x40
[84314.936886] [<ffffffff8177a41c>] ? __do_page_fault+0x20c/0x5a0
[84314.936892] [<ffffffff811b2946>] do_vfs_ioctl+0x96/0x570
[84314.936896] [<ffffffff81776e23>] ? error_sti+0x5/0x6
[84314.936901] [<ffffffff810b71e8>] ? trace_hardirqs_off_caller+0x28/0xd0
[84314.936906] [<ffffffff81776a09>] ? retint_swapgs+0xe/0x13
[84314.936910] [<ffffffff811b2eb1>] SyS_ioctl+0x91/0xb0
[84314.936915] [<ffffffff813eecde>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[84314.936920] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
[84314.936922] INFO: lockdep is turned off.
[84434.866873] INFO: task btrfs-transacti:11921 blocked for more than 120 seconds.
[84434.866881] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70
[84434.866883] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[84434.866886] btrfs-transacti D ffff880755b6a478 0 11921 2 0x00000000
[84434.866893] ffff8800735b9ce8 0000000000000046 ffff8800735b9c88 ffffffff810bd8bd
[84434.866899] ffff8805a1b848a0 ffff8800735b9fd8 ffff8800735b9fd8 ffff8800735b9fd8
[84434.866904] ffffffff81c104e0 ffff8805a1b848a0 ffff880755b6a478 ffff8804cece78f0
[84434.866910] Call Trace:
[84434.866920] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10
[84434.866927] [<ffffffff81774269>] schedule+0x29/0x70
[84434.866948] [<ffffffffa06dd2ef>] wait_current_trans.isra.33+0xbf/0x120 [btrfs]
[84434.866954] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60
[84434.866970] [<ffffffffa06dec18>] start_transaction+0x388/0x5a0 [btrfs]
[84434.866985] [<ffffffffa06db9b5>] ? transaction_kthread+0xb5/0x280 [btrfs]
[84434.866999] [<ffffffffa06dee97>] btrfs_attach_transaction+0x17/0x20 [btrfs]
[84434.867012] [<ffffffffa06dba9e>] transaction_kthread+0x19e/0x280 [btrfs]
[84434.867026] [<ffffffffa06db900>] ? open_ctree+0x2260/0x2260 [btrfs]
[84434.867030] [<ffffffff81070dad>] kthread+0xed/0x100
[84434.867035] [<ffffffff81070cc0>] ? flush_kthread_worker+0x190/0x190
[84434.867040] [<ffffffff8177ee6c>] ret_from_fork+0x7c/0xb0
[84434.867044] [<ffffffff81070cc0>] ? flush_kthread_worker+0x190/0x190
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Chris introduced hleper function read_csums() and this function
has been removed, but we forgot to remove its corresponding comments.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
It's not used anywhere, so just drop it.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
fs/btrfs/file.c: In function ‘prepare_pages.isra.18’:
fs/btrfs/file.c:1265:6: warning: ‘err’ may be used uninitialized in this function [-Wuninitialized]
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We have commited transaction before, remove redundant filemap writting and
waiting here, it can speed up balance relocation process.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Clean up btrfs_lookup_dentry() to never return NULL, but PTR_ERR(-ENOENT)
instead. This keeps the return value convention consistent.
Callers who use btrfs_lookup_dentry() require a trivial update.
create_snapshot() in particular looks like it can also lose a BUG_ON(!inode)
which is not really needed - there seems less harm in returning ENOENT to
userspace at that point in the stack than there is to crash the machine.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
In ctree.c:tree_mod_log_set_node_key() we were calling
__tree_mod_log_insert_key() even when the modification doesn't need
to be logged. This would allocate a tree_mod_elem structure, fill it
and pass it to __tree_mod_log_insert(), which would just acquire
the tree mod log write lock and then free the tree_mod_elem structure
and return (that is, a no-op).
Therefore call tree_mod_log_insert() instead of __tree_mod_log_insert()
which just returns immediately if the modification doesn't need to be
logged (without allocating the structure, fill it, acquire write lock,
free structure).
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
I need to create a fake tree to test qgroups and I don't want to have to setup a
fake btree_inode. The fact is we only use the radix tree for the fs_info, so
everybody else who allocates an extent_io_tree is just wasting the space anyway.
This patch moves the radix tree and its lock into btrfs_fs_info so there is less
stuff I have to fake to do qgroup sanity tests. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
For creating a dummy in-memory btree I need to be able to use the radix tree to
keep track of the buffers like normal extent buffers. With dummy buffers we
skip the radix tree step, and we still want to do that for the tree mod log
dummy buffers but for my test buffers we need to be able to remove them from the
radix tree like normal. This will give me a way to do that. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
I need to add infrastructure to allocate dummy extent buffers for running sanity
tests, and to do this I need to not have to worry about having an
address_mapping for an io_tree, so just fix up the places where we assume that
all io_tree's have a non-NULL ->mapping. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently when finding the leaf to insert a key into a btree, if the
leaf doesn't have enough space to store the item we attempt to move
off some items from our leaf to its right neighbor leaf, and if this
fails to create enough free space in our leaf, we try to move off more
items to the left neighbor leaf as well.
When trying to move off items to the right neighbor leaf, if it has
enough room to store the new key but not not enough room to move off
at least one item from our target leaf, __push_leaf_right returns 1 and
we have to attempt to move items to the left neighbor (push_leaf_left
function) without touching the right neighbor leaf.
For the case where the right leaf has enough room to store at least 1
item from our leaf, we end up modifying (and dirtying) both our leaf
and the right leaf. This is non-optimal for the case where the new key
is greater than any key in our target leaf because it can be inserted at
slot 0 of the right neighbor leaf and we don't need to touch our leaf
at all nor to attempt to move off items to the left neighbor leaf.
Therefore this change just selects the right neighbor leaf as our new
target leaf if it has enough room for the new key without modifying our
initial target leaf - we do this only if the new key is higher than any
key in the initial target leaf.
While running the following test, push_leaf_right was called by split_leaf
4802 times. Out of those 4802 calls, for 2571 calls (53.5%) we hit this
special case (right leaf has enough room and new key is higher than any key
in the initial target leaf).
Test:
sysbench --test=fileio --file-num=512 --file-total-size=5G \
--file-test-mode=[seqwr|rndwr] --num-threads=512 --file-block-size=8192 \
--max-requests=100000 --file-io-mode=sync [prepare|run]
Results:
sequential writes
Throughput before this change: 65.71Mb/sec (average of 10 runs)
Throughput after this change: 66.58Mb/sec (average of 10 runs)
random writes
Throughput before this change: 10.75Mb/sec (average of 10 runs)
Throughput after this change: 11.56Mb/sec (average of 10 runs)
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Just wrap same code into one function scrub_blocked_if_needed().
This make a change that we will move waiting (@workers_pending = 0)
before we can wake up commiting transaction(atomic_inc(@scrub_paused)),
we must take carefully to not deadlock here.
Thread 1 Thread 2
|->btrfs_commit_transaction()
|->set trans type(COMMIT_DOING)
|->btrfs_scrub_paused()(blocked)
|->join_transaction(blocked)
Move btrfs_scrub_paused() before setting trans type which means we can
still join a transaction when commiting_transaction is blocked.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Suggested-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We came a race condition when scrubbing superblocks, the story is:
In commiting transaction, we will update @last_trans_commited after
writting superblocks, if scrubber start after writting superblocks
and before updating @last_trans_commited, generation mismatch happens!
We fix this by checking @scrub_pause_req, and we won't start a srubber
until commiting transaction is finished.(after btrfs_scrub_continue()
finished.)
Reported-by: Sebastian Ochmann <ochmann@informatik.uni-bonn.de>
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
fs/btrfs/send.c:2190:9: warning: incorrect type in argument 3 (different base types)
fs/btrfs/send.c:2190:9: expected unsigned long long [unsigned] [usertype] value
fs/btrfs/send.c:2190:9: got restricted __le64 [usertype] ctransid
fs/btrfs/send.c:2195:17: warning: incorrect type in argument 3 (different base types)
fs/btrfs/send.c:2195:17: expected unsigned long long [unsigned] [usertype] value
fs/btrfs/send.c:2195:17: got restricted __le64 [usertype] ctransid
fs/btrfs/send.c:3716:9: warning: incorrect type in argument 3 (different base types)
fs/btrfs/send.c:3716:9: expected unsigned long long [unsigned] [usertype] value
fs/btrfs/send.c:3716:9: got restricted __le64 [usertype] ctransid
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
When merging an extent_map with its right neighbor, increment
its block_len with the neighbor's block_len.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
[commit 8185554d: fix incorrect inode acl reset] introduced a dead
code by adding a condition which can never be true to an else
branch. The condition can never be true because it is already
checked by a previous if statement which causes function to return.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-By: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We were accounting for sizeof(struct btrfs_item) twice, once
in the data_size variable and another time in the if statement
below.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently we do 2 traversals of an inode's extent_io_tree
before inserting an extent state structure: 1 to see if a
matching extent state already exists and 1 to do the insertion
if the fist traversal didn't found such extent state.
This change just combines those tree traversals into a single one.
While running sysbench tests (random writes) I captured the number
of elements in extent_io_tree trees for a while (into a procfs file
backed by a seq_list from seq_file module) and got this histogram:
Count: 9310
Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688
Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000
51.000 - 93.933: 693 ########
93.933 - 172.314: 938 ##########
172.314 - 315.408: 856 #########
315.408 - 576.646: 95 #
576.646 - 6415.830: 888 ##########
6415.830 - 11713.809: 1024 ###########
11713.809 - 21386.000: 4816 #####################################################
So traversing such trees can take some significant time that can
easily be avoided.
Ran the following sysbench tests, 5 times each, for sequential and
random writes, and got the following results:
sysbench --test=fileio --file-num=1 --file-total-size=2G \
--file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \
--max-requests=0 --max-time=60 --file-io-mode=sync
sysbench --test=fileio --file-num=1 --file-total-size=2G \
--file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \
--max-requests=0 --max-time=60 --file-io-mode=sync
Before this change:
sequential writes: 69.28Mb/sec (average of 5 runs)
random writes: 4.14Mb/sec (average of 5 runs)
After this change:
sequential writes: 69.91Mb/sec (average of 5 runs)
random writes: 5.69Mb/sec (average of 5 runs)
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we didn't find a matching extent state, we inserted a new one
but didn't cache it in the **cached_state parameter, which makes a
subsequent call do a tree lookup to get it.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Before this change, adding an extent map to the extent map tree of an
inode required 2 tree nevigations:
1) doing a tree navigation to search for an existing extent map starting
at the same offset or an extent map that overlaps the extent map we
want to insert;
2) Another tree navigation to add the extent map to the tree (if the
former tree search didn't found anything).
This change just merges these 2 steps into a single one.
While running first few btrfs xfstests I had noticed these trees easily
had a few hundred elements, and then with the following sysbench test it
reached over 1100 elements very often.
Test:
sysbench --test=fileio --file-num=32 --file-total-size=10G \
--file-test-mode=seqwr --num-threads=512 --file-block-size=8192 \
--max-requests=1000000 --file-io-mode=sync [prepare|run]
(fs created with mkfs.btrfs -l 4096 -f /dev/sdb3 before each sysbench
prepare phase)
Before this patch:
run 1 - 41.894Mb/sec
run 2 - 40.527Mb/sec
run 3 - 40.922Mb/sec
run 4 - 49.433Mb/sec
run 5 - 40.959Mb/sec
average - 42.75Mb/sec
After this patch:
run 1 - 48.036Mb/sec
run 2 - 50.21Mb/sec
run 3 - 50.929Mb/sec
run 4 - 46.881Mb/sec
run 5 - 53.192Mb/sec
average - 49.85Mb/sec
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
When attempting to move items from our target leaf to its neighbor
leaves (right and left), we only need to free data_size - free_space
bytes from our leaf in order to add the new item (which has size of
data_size bytes). Therefore attempt to move items to the right and
left leaves if they have at least data_size - free_space bytes free,
instead of data_size bytes free.
After 5 runs of the following test, I got a smaller number of btree
node splits overall:
sysbench --test=fileio --file-num=512 --file-total-size=5G \
--file-test-mode=seqwr --num-threads=512 \
--file-block-size=8192 --max-requests=100000 --file-io-mode=sync
Before this change:
* 6171 splits (average of 5 test runs)
* 61.508Mb/sec of throughput (average of 5 test runs)
After this change:
* 6036 splits (average of 5 test runs)
* 63.533Mb/sec of throughput (average of 5 test runs)
An ideal test would not just have multiple threads/processes writing
to a file (insertion of file extent items) but also do other operations
that result in insertion of items with varied sizes, like file/directory
creations, creation of links, symlinks, xattrs, etc.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
After an ordered extent completes, don't blindly reset the
inode's ordered tree last accessed ordered extent pointer.
While running the xfstests I noticed that about 29% of the
time the ordered extent to which tree->last pointed was not
the same as our just completed ordered extent. After that I
ran the following sysbench test (after a prepare phase) and
noticed that about 68% of the time tree->last pointed to
a different ordered extent too.
sysbench --test=fileio --file-num=32 --file-total-size=4G \
--file-test-mode=rndwr --num-threads=512 \
--file-block-size=32768 --max-time=60 --max-requests=0 run
Therefore reset tree->last on ordered extent removal only if
it pointed to the ordered extent we're removing from the tree.
Results from 4 runs of the following test before and after
applying this patch:
$ sysbench --test=fileio --file-num=32 --file-total-size=4G \
--file-test-mode=seqwr --num-threads=512 \
--file-block-size=32768 --max-time=60 --file-io-mode=sync prepare
$ sysbench --test=fileio --file-num=32 --file-total-size=4G \
--file-test-mode=seqwr --num-threads=512 \
--file-block-size=32768 --max-time=60 --file-io-mode=sync run
Before this path:
run 1 - 64.049Mb/sec
run 2 - 63.455Mb/sec
run 3 - 64.656Mb/sec
run 4 - 63.833Mb/sec
After this patch:
run 1 - 66.149Mb/sec
run 2 - 68.459Mb/sec
run 3 - 66.338Mb/sec
run 4 - 66.176Mb/sec
With random writes (--file-test-mode=rndwr) I had huge fluctuations
on the results (+- 35% easily).
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Filipe noticed that we were leaking the features attribute group
after umount. His fix of just calling sysfs_remove_group() wasn't enough
since that removes just the supported features and not the unsupported
features.
This patch changes the unknown feature handling to add them individually
so we can skip the kmalloc and uses the same iteration to tear them down
later.
We also fix the error handling during mount so that we catch the
failing creation of the per-super kobject, and handle proper teardown
of a half-setup sysfs context.
Tested properly with kmemleak enabled this time.
Reported-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
This patch fixes the following warnings:
fs/btrfs/extent-tree.c:6201:12: sparse: symbol 'get_raid_name' was not declared. Should it be static?
fs/btrfs/extent-tree.c:8430:9: error: format not a string literal and no format arguments [-Werror=format-security] get_raid_name(index));
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
The inode eviction can be very slow, because during eviction we
tell the VFS to truncate all of the inode's pages. This results
in calls to btrfs_invalidatepage() which in turn does calls to
lock_extent_bits() and clear_extent_bit(). These calls result in
too many merges and splits of extent_state structures, which
consume a lot of time and cpu when the inode has many pages. In
some scenarios I have experienced umount times higher than 15
minutes, even when there's no pending IO (after a btrfs fs sync).
A quick way to reproduce this issue:
$ mkfs.btrfs -f /dev/sdb3
$ mount /dev/sdb3 /mnt/btrfs
$ cd /mnt/btrfs
$ sysbench --test=fileio --file-num=128 --file-total-size=16G \
--file-test-mode=seqwr --num-threads=128 \
--file-block-size=16384 --max-time=60 --max-requests=0 run
$ time btrfs fi sync .
FSSync '.'
real 0m25.457s
user 0m0.000s
sys 0m0.092s
$ cd ..
$ time umount /mnt/btrfs
real 1m38.234s
user 0m0.000s
sys 1m25.760s
The same test on ext4 runs much faster:
$ mkfs.ext4 /dev/sdb3
$ mount /dev/sdb3 /mnt/ext4
$ cd /mnt/ext4
$ sysbench --test=fileio --file-num=128 --file-total-size=16G \
--file-test-mode=seqwr --num-threads=128 \
--file-block-size=16384 --max-time=60 --max-requests=0 run
$ sync
$ cd ..
$ time umount /mnt/ext4
real 0m3.626s
user 0m0.004s
sys 0m3.012s
After this patch, the unmount (inode evictions) is much faster:
$ mkfs.btrfs -f /dev/sdb3
$ mount /dev/sdb3 /mnt/btrfs
$ cd /mnt/btrfs
$ sysbench --test=fileio --file-num=128 --file-total-size=16G \
--file-test-mode=seqwr --num-threads=128 \
--file-block-size=16384 --max-time=60 --max-requests=0 run
$ time btrfs fi sync .
FSSync '.'
real 0m26.774s
user 0m0.000s
sys 0m0.084s
$ cd ..
$ time umount /mnt/btrfs
real 0m1.811s
user 0m0.000s
sys 0m1.564s
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We hit a forever loop when doing balance relocation,the reason
is that we firstly reserve 4M(node size is 16k).and within transaction
we will try to add extra reservation for snapshot roots,this will
return -EAGAIN if there has been a thread flushing space to reserve
space.We will do this again and again with filesystem becoming nearly
full.
If the above '-EAGAIN' case happens, we try to refill reservation more
outsize of transaction, and this will return eariler in enospc case,however,
this dosen't really hurt because it makes no sense doing balance relocation
with the filesystem nearly full.
Miao Xie helped a lot to track this issue, thanks.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
If the ordered extent's last byte was 1 less than our region's
start byte, we would unnecessarily wait for the completion of
that ordered extent, because it doesn't intersect our target
range.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we ran sysbench on the fs with compression, the following WARN_ONs were
triggered:
fs/btrfs/inode.c:7829 WARN_ON(BTRFS_I(inode)->outstanding_extents);
fs/btrfs/inode.c:7830 WARN_ON(BTRFS_I(inode)->reserved_extents);
fs/btrfs/inode.c:7832 WARN_ON(BTRFS_I(inode)->csum_bytes);
Steps to reproduce:
# mkfs.btrfs -f <dev>
# mount -o compress <dev> <mnt>
# cd <mnt>
# sysbench --test=fileio --num-threads=8 --file-total-size=8G \
> --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \
> --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \
> --file-test-mode=sync prepare
# cd -
# umount <mnt>
# mount -o compress <dev> <mnt>
# cd <mnt>
# sysbench --test=fileio --num-threads=8 --file-total-size=8G \
> --file-block-size=32K --file-io-mode=rndwr --file-fsync-freq=0 \
> --file-fsync-end=no --max-requests=300000 --file-extra-flags=direct \
> --file-test-mode=sync run
# cd -
# umount <mnt>
The reason of this problem is:
Task0 Task1
btrfs_direct_IO
unlock(&inode->i_mutex)
lock(&inode->i_mutex)
reserve_space()
prepare_pages()
lock_extent()
clear_extent()
unlock_extent()
lock_extent()
test_extent(uptodate)
return false
copy_data()
set_delalloc_extent()
extent need compress
go back to buffered write
clear_extent(DELALLOC | DIRTY)
unlock_extent()
Task 0 and 1 wrote the same place, and task0 cleared the delalloc flag which
was set by task1, it made the dirty pages in that extents couldn't be flushed
into the disk, so the reserved space for that extent was not released at
the end.
This patch fixes the above bug by unlocking the extent after the delalloc.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
- the caller has gotten the inode object, needn't pass the file object.
And if so, we needn't define a inode pointer variant.
- the position should be aligned by the page size not sector size, so
we also needn't pass the root object into prepare_pages().
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We don't need to crash hard here, it's just reading a sysfs file. The
values considered in switch are from a fixed set, the default case
should not happen at all.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Added in patch "btrfs: add ability to change features via sysfs",
modifications to superblock don't need to reserve metadata blocks when
starting a transaction.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
The kernel macro pr_debug is defined as a empty statement when DEBUG is
not defined. Make btrfs_debug match pr_debug to avoid spamming
the kernel log with debug messages
Signed-off-by: Frank Holton <fholton@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
Found by uselex.rb:
> btrfs_get_inode_ref_index: [R]: exported from:
fs/btrfs/inode-item.o fs/btrfs/btrfs.o fs/btrfs/built-in.o
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Reviewed-by: David Stebra <dsterba@suse.cz>
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
This is the third step in bootstrapping the btrfs_find_item interface.
The function find_orphan_item(), in orphan.c, is similar to the two
functions already replaced by the new interface. It uses two parameters,
which are already present in the interface, and is nearly identical to
the function brought in in the previous patch.
Replace the two calls to find_orphan_item() with calls to
btrfs_find_item(), with the defined objectid and type that was used
internally by find_orphan_item(), a null path, and a null key. Add a
test for a null path to btrfs_find_item, and if it passes, allocate and
free the path. Finally, remove find_orphan_item().
Signed-off-by: Kelley Nielsen <kelleynnn@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
This patch is the second step in bootstrapping the btrfs_find_item
interface. The btrfs_find_root_ref() is similar to the former
__inode_info(); it accepts four of its parameters, and duplicates the
first half of its functionality.
Replace the one former call to btrfs_find_root_ref() with a call to
btrfs_find_item(), along with the defined key type that was used
internally by btrfs_find_root ref, and a null found key. In
btrfs_find_item(), add a test for the null key at the place where
the functionality of btrfs_find_root_ref() ends; btrfs_find_item()
then returns if the test passes. Finally, remove btrfs_find_root_ref().
Signed-off-by: Kelley Nielsen <kelleynnn@gmail.com>
Suggested-by: Zach Brown <zab@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
Miao Xie