From: Florian Stecker <m19@florianstecker.de>
To: Nikolay Borisov <nborisov@suse.com>, linux-btrfs@vger.kernel.org
Subject: Re: applications hang on a btrfs spanning two partitions
Date: Wed, 9 Jan 2019 10:16:10 +0100 [thread overview]
Message-ID: <2d2ac67d-3cf5-d147-f57b-785dc633821d@florianstecker.de> (raw)
In-Reply-To: <51f6646b-ca38-9b34-7061-8ab5227f00ae@suse.com>
>
> Provide output of echo w > /proc/sysrq-trigger when the hang occurs
> otherwise it's hard to figure what's going on.
>
Here's one, again in gajim. This time, fdatasync() took "only" 2 seconds:
[42481.243491] sysrq: SysRq : Show Blocked State
[42481.243494] task PC stack pid father
[42481.243566] gajim D 0 15778 15774 0x00000083
[42481.243569] Call Trace:
[42481.243575] ? __schedule+0x29b/0x8b0
[42481.243576] ? bit_wait+0x50/0x50
[42481.243578] schedule+0x32/0x90
[42481.243580] io_schedule+0x12/0x40
[42481.243582] bit_wait_io+0xd/0x50
[42481.243583] __wait_on_bit+0x6c/0x80
[42481.243585] out_of_line_wait_on_bit+0x91/0xb0
[42481.243587] ? init_wait_var_entry+0x40/0x40
[42481.243605] write_all_supers+0x418/0xa70 [btrfs]
[42481.243622] btrfs_sync_log+0x695/0x910 [btrfs]
[42481.243625] ? _raw_spin_lock_irqsave+0x25/0x50
[42481.243641] ? btrfs_log_dentry_safe+0x54/0x70 [btrfs]
[42481.243655] btrfs_sync_file+0x3a9/0x3d0 [btrfs]
[42481.243659] do_fsync+0x38/0x70
[42481.243661] __x64_sys_fdatasync+0x13/0x20
[42481.243663] do_syscall_64+0x5b/0x170
[42481.243666] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[42481.243667] RIP: 0033:0x7fd4022f873f
[42481.243671] Code: Bad RIP value.
[42481.243672] RSP: 002b:00007ffd3710a300 EFLAGS: 00000293 ORIG_RAX:
000000000000004b
[42481.243674] RAX: ffffffffffffffda RBX: 0000000000000019 RCX:
00007fd4022f873f
[42481.243675] RDX: 0000000000000000 RSI: 0000000000000002 RDI:
0000000000000019
[42481.243675] RBP: 0000000000000000 R08: 000055d8d8649f68 R09:
00007ffd3710a320
[42481.243676] R10: 0000000000013000 R11: 0000000000000293 R12:
0000000000000000
[42481.243677] R13: 0000000000000000 R14: 000055d8d8363fa0 R15:
000055d8d8613040
On 1/9/19 7:24 AM, Nikolay Borisov wrote:
>
>
> On 8.01.19 г. 21:38 ч., Florian Stecker wrote:
>> Hi everyone,
>>
>> I extended the btrfs volume on my laptop by adding a second partition to
>> it which lies on the same SSD (using btrfs device add). Since I did
>> this, all kinds of applications regularly hang for up to 30 seconds. It
>> seems they are stuck in the fdatasync syscall. For example:
>>
>> $ strace -tt -T gajim 2>&1 | grep fdatasync
>> [...]
>> 11:36:31.112200 fdatasync(25) = 0 <0.006958>
>> 11:36:32.147525 fdatasync(25) = 0 <0.008138>
>> 11:36:32.156882 fdatasync(25) = 0 <0.006866>
>> 11:36:32.165979 fdatasync(25) = 0 <0.011797>
>> 11:36:32.178867 fdatasync(25) = 0 <23.636614>
>> 11:36:55.827726 fdatasync(25) = 0 <0.009595>
>> 11:36:55.838702 fdatasync(25) = 0 <0.007261>
>> 11:36:55.850440 fdatasync(25) = 0 <0.006807>
>> 11:36:55.858168 fdatasync(25) = 0 <0.006767>
>> [...]
>>
>> File descriptor 25 here points to a file which is just ~90KB, so it
>> really shouldn't take that long.
>>
>> Removing the second partition again resolves the problem. Does anyone
>> know this issue? Is it related to btrfs? Or am I just doing something
>> wrong?
>>
>> Best,
>> Florian
>>
>> Some more info:
>>
>> $ btrfs device usage /
>> /dev/sda2, ID: 2
>> Device size: 52.16GiB
>> Device slack: 0.00B
>> Data,single: 1.00GiB
>> Unallocated: 51.16GiB
>>
>> /dev/sda8, ID: 1
>> Device size: 174.92GiB
>> Device slack: 0.00B
>> Data,single: 168.91GiB
>> Metadata,single: 3.01GiB
>> System,single: 4.00MiB
>> Unallocated: 3.00GiB
>>
>> $ fdisk -l /dev/sda
>> Disk /dev/sda: 238.5 GiB, 256060514304 bytes, 500118192 sectors
>> Disk model: SAMSUNG SSD PM87
>> Units: sectors of 1 * 512 = 512 bytes
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>> Disklabel type: gpt
>> Disk identifier: A48B5A25-AA84-4D3F-90DD-E8A4991BDF03
>>
>> Device Start End Sectors Size Type
>> /dev/sda1 2048 1026047 1024000 500M EFI System
>> /dev/sda2 1026048 110422015 109395968 52.2G Linux filesystem
>> /dev/sda8 110422016 477263871 366841856 174.9G Linux filesystem
>> /dev/sda9 477263872 481458175 4194304 2G Linux swap
>>
>> $ uname -a
>> Linux dell 4.20.0-arch1-1-ARCH #1 SMP PREEMPT Mon Dec 24 03:00:40 UTC
>> 2018 x86_64 GNU/Linux
>
>>
>>
next prev parent reply other threads:[~2019-01-09 9:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-08 19:38 applications hang on a btrfs spanning two partitions Florian Stecker
2019-01-09 6:24 ` Nikolay Borisov
2019-01-09 9:16 ` Florian Stecker [this message]
2019-01-09 10:03 ` Nikolay Borisov
2019-01-09 20:10 ` Florian Stecker
2019-01-12 2:12 ` Chris Murphy
2019-01-12 10:19 ` Florian Stecker
2019-01-14 5:49 ` Duncan
2019-01-14 11:35 ` Marc Joliet
2019-01-15 8:33 ` Duncan
2019-01-15 22:40 ` Marc Joliet
2019-01-17 11:15 ` Duncan
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