On Wed, Nov 26, 2014 at 10:00 PM, Miao Xie <mi...@cn.fujitsu.com> wrote:
On Thu, 27 Nov 2014 09:39:56 +0800, Miao Xie wrote:
On Wed, 26 Nov 2014 10:02:23 -0500, Chris Mason wrote:
On Wed, Nov 26, 2014 at 8:04 AM, Miao Xie <mi...@cn.fujitsu.com>
wrote:
The increase/decrease of bio counter is on the I/O path, so we
should
use io_schedule() instead of schedule(), or the deadlock might be
triggered by the pending I/O in the plug list. io_schedule() can
help
us because it will flush all the pending I/O before the task is
going
to sleep.
Can you please describe this deadlock in more detail? schedule()
also triggers
a flush of the plug list, and if that's no longer sufficient we
can run into other
problems (especially with preemption on).
Sorry for my miss. I forgot to check the current implementation of
schedule(), which flushes the plug list unconditionally. Please
ignore this patch.
I have updated my raid56-scrub-replace branch, please re-pull the
branch.
https://github.com/miaoxie/linux-btrfs.git raid56-scrub-replace
Sorry, I wasn't clear. I do like the patch because it uses a slightly
better trigger mechanism for the flush. I was just worried about a
larger deadlock.
I ran the raid56 work with stress.sh overnight, then scrubbed the
resulting filesystem and ran balance when the scrub completed. All of
these passed without errors (excellent!).
Then I zero'd 4GB of one drive and ran scrub again. This was the
result. Please make sure CONFIG_DEBUG_PAGEALLOC is enabled and you
should be able to reproduce.
[192392.495260] BUG: unable to handle kernel paging request at
ffff880303062f80
[192392.495279] IP: [<ffffffffa05fe77a>] lock_stripe_add+0xba/0x390
[btrfs]
[192392.495281] PGD 2bdb067 PUD 107e7fd067 PMD 107e7e4067 PTE
8000000303062060
[192392.495283] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
[192392.495307] Modules linked in: ipmi_devintf loop fuse k10temp
coretemp hwmon btrfs raid6_pq zlib_deflate lzo_compress xor xfs
exportfs libcrc32c tcp_diag inet_diag nfsv4 ip6table_filter ip6_tables
xt_NFLOG nfnetlink_log nfnetlink xt_comment xt_statistic iptable_filter
ip_tables x_tables mptctl netconsole autofs4 nfsv3 nfs lockd grace
rpcsec_gss_krb5 auth_rpcgss oid_registry sunrpc ipv6 ext3 jbd dm_mod
rtc_cmos ipmi_si ipmi_msghandler iTCO_wdt iTCO_vendor_support pcspkr
i2c_i801 lpc_ich mfd_core shpchp ehci_pci ehci_hcd mlx4_en ptp pps_core
mlx4_core sg ses enclosure button megaraid_sas
[192392.495310] CPU: 0 PID: 11992 Comm: kworker/u65:2 Not tainted
3.18.0-rc6-mason+ #7
[192392.495310] Hardware name: ZTSYSTEMS Echo Ridge T4 /A9DRPF-10D,
BIOS 1.07 05/10/2012
[192392.495323] Workqueue: btrfs-btrfs-scrub btrfs_scrub_helper [btrfs]
[192392.495324] task: ffff88013dae9110 ti: ffff8802296a0000 task.ti:
ffff8802296a0000
[192392.495335] RIP: 0010:[<ffffffffa05fe77a>] [<ffffffffa05fe77a>]
lock_stripe_add+0xba/0x390 [btrfs]
[192392.495335] RSP: 0018:ffff8802296a3ac8 EFLAGS: 00010006
[192392.495336] RAX: ffff880577e85018 RBX: ffff880497f0b2f8 RCX:
ffff8801190fb000
[192392.495337] RDX: 000000000000013d RSI: ffff880303062f80 RDI:
0000040c275a0000
[192392.495338] RBP: ffff8802296a3b48 R08: ffff880497f00000 R09:
0000000000000001
[192392.495339] R10: 0000000000000000 R11: 0000000000000000 R12:
0000000000000282
[192392.495339] R13: 000000000000b250 R14: ffff880577e85000 R15:
ffff880497f0b2a0
[192392.495340] FS: 0000000000000000(0000) GS:ffff88085fc00000(0000)
knlGS:0000000000000000
[192392.495341] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[192392.495342] CR2: ffff880303062f80 CR3: 0000000005289000 CR4:
00000000000407f0
[192392.495342] Stack:
[192392.495344] ffff880755e28000 ffff880497f00000 000000000000013d
ffff8801190fb000
[192392.495346] 0000000000000000 ffff88013dae9110 ffffffff81090d40
ffff8802296a3b00
[192392.495347] ffff8802296a3b00 0000000000000010 ffff8802296a3b68
ffff8801190fb000
[192392.495348] Call Trace:
[192392.495353] [<ffffffff81090d40>] ? bit_waitqueue+0xa0/0xa0
[192392.495363] [<ffffffffa05fea66>]
raid56_parity_submit_scrub_rbio+0x16/0x30 [btrfs]
[192392.495372] [<ffffffffa05e2f0e>]
scrub_parity_check_and_repair+0x15e/0x1e0 [btrfs]
[192392.495380] [<ffffffffa05e301d>] scrub_block_put+0x8d/0x90 [btrfs]
[192392.495388] [<ffffffffa05e6ed7>] ?
scrub_bio_end_io_worker+0xd7/0x870 [btrfs]
[192392.495396] [<ffffffffa05e6ee9>]
scrub_bio_end_io_worker+0xe9/0x870 [btrfs]
[192392.495405] [<ffffffffa05b8c44>] normal_work_helper+0x84/0x330
[btrfs]
[192392.495414] [<ffffffffa05b8f42>] btrfs_scrub_helper+0x12/0x20
[btrfs]
[192392.495417] [<ffffffff8106c50f>] process_one_work+0x1bf/0x520
[192392.495419] [<ffffffff8106c48d>] ? process_one_work+0x13d/0x520
[192392.495421] [<ffffffff8106c98e>] worker_thread+0x11e/0x4b0
[192392.495424] [<ffffffff81653ac9>] ? __schedule+0x389/0x880
[192392.495426] [<ffffffff8106c870>] ? process_one_work+0x520/0x520
[192392.495428] [<ffffffff81071e2e>] kthread+0xde/0x100
[192392.495430] [<ffffffff81071d50>] ? __init_kthread_worker+0x70/0x70
[192392.495431] [<ffffffff81659eac>] ret_from_fork+0x7c/0xb0
[192392.495433] [<ffffffff81071d50>] ? __init_kthread_worker+0x70/0x70
[192392.495449] Code: 45 88 49 89 c4 4f 8d 7c 28 50 4b 8b 44 28 50 48
8b 55 90 4c 8d 70 e8 4c 39 f8 48 8b 4d 98 74 32 48 8b 71 10 48 8b 3e 48
8b 70 f8 <48> 39 3e 75 12 eb 6f 0f 1f 80 00 00 00 00 48 8b 76 f8 48 39
3e
[192392.495458] RIP [<ffffffffa05fe77a>] lock_stripe_add+0xba/0x390
[btrfs]
[192392.495458] RSP <ffff8802296a3ac8>
[192392.495458] CR2: ffff880303062f80
[192392.496389] ---[ end trace c04c23ee0d843df0 ]---
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