* Re: [PATCH 2/2] pnfsblock: fix writeback deadlock
[not found] ` <1315622957-1549-2-git-send-email-bergwolf@gmail.com>
@ 2011-09-13 16:09 ` Peng Tao
0 siblings, 0 replies; 2+ messages in thread
From: Peng Tao @ 2011-09-13 16:09 UTC (permalink / raw)
To: Trond Myklebust; +Cc: Benny Halevy, Jim Rees, Peng Tao, linuxnfs
And this one too... Add cc nfs list. Sorry for the noise...
On Sat, Sep 10, 2011 at 10:49 AM, Peng Tao <bergwolf@gmail.com> wrote:
> We should check if the sector is already initialized before
> trying to grab the page from page cache. Otherwise when two
> pages of the same block are written back by two threads each
> calling from writepage_locked, it can cause deadlock like bellow.
>
> [ 1080.972099] INFO: task kswapd0:25 blocked for more than 120 seconds.
> [ 1080.972377] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 1080.972812] kswapd0 D ffff88000c4926c0 0 25 2 0x00000000
> [ 1080.972816] ffff88000df276b0 0000000000000046 ffff88000df27640 ffffffff81013ba7
> [ 1080.972821] ffff88000c492310 ffff88000df27fd8 ffff88000df27fd8 00000000001d3440
> [ 1080.972824] ffff88000c378000 ffff88000c492310 ffff8800175d3d40 ffff880017fc75a8
> [ 1080.972828] Call Trace:
> [ 1080.972860] [<ffffffff81013ba7>] ? read_tsc+0x9/0x19
> [ 1080.972877] [<ffffffff810e0b23>] ? lock_page+0x2b/0x2b
> [ 1080.972899] [<ffffffff81475a1d>] io_schedule+0x63/0x7e
> [ 1080.972902] [<ffffffff810e0b31>] sleep_on_page+0xe/0x12
> [ 1080.972905] [<ffffffff81475fe8>] __wait_on_bit_lock+0x46/0x8f
> [ 1080.972916] [<ffffffff810822d7>] ? lock_release_holdtime.part.7+0x6b/0x72
> [ 1080.972919] [<ffffffff810e0af6>] __lock_page+0x66/0x68
> [ 1080.972928] [<ffffffff81072705>] ? autoremove_wake_function+0x3d/0x3d
> [ 1080.972932] [<ffffffff810e0b1f>] lock_page+0x27/0x2b
> [ 1080.972934] [<ffffffff810e0bcf>] find_lock_page+0x34/0x57
> [ 1080.972937] [<ffffffff810e1738>] find_or_create_page+0x34/0x8a
> [ 1080.972947] [<ffffffffa034245b>] bl_write_pagelist+0x205/0x6da [blocklayoutdriver]
> [ 1080.972951] [<ffffffffa034145d>] ? bl_free_lseg+0x38/0x38 [blocklayoutdriver]
> [ 1080.972995] [<ffffffffa02e27b9>] ? nfs_write_rpcsetup+0x118/0x123 [nfs]
> [ 1080.973033] [<ffffffffa030246b>] pnfs_generic_pg_writepages+0x10b/0x1f4 [nfs]
> [ 1080.973089] [<ffffffffa02deaae>] nfs_pageio_doio+0x1a/0x43 [nfs]
> [ 1080.973098] [<ffffffffa02df035>] nfs_pageio_complete+0x16/0x2d [nfs]
> [ 1080.973108] [<ffffffffa02e2d8f>] nfs_writepage_locked+0xa0/0xbf [nfs]
> [ 1080.973119] [<ffffffffa02e36a1>] nfs_writepage+0x16/0x2b [nfs]
> [ 1080.973122] [<ffffffff810e8762>] ? clear_page_dirty_for_io+0x87/0x9a
> [ 1080.973133] [<ffffffff810efc5b>] shrink_page_list+0x39b/0x6c8
> [ 1080.973139] [<ffffffff810f03bb>] shrink_inactive_list+0x22c/0x39e
> [ 1080.973144] [<ffffffff810822d7>] ? lock_release_holdtime.part.7+0x6b/0x72
> [ 1080.973148] [<ffffffff810f0c33>] shrink_zone+0x445/0x588
> [ 1080.973152] [<ffffffff810f1a11>] balance_pgdat+0x2c2/0x56b
> [ 1080.973170] [<ffffffff81254208>] ? __bitmap_weight+0x34/0x80
> [ 1080.973175] [<ffffffff810f1f78>] kswapd+0x2be/0x2fa
> [ 1080.973179] [<ffffffff810726c8>] ? __init_waitqueue_head+0x4b/0x4b
> [ 1080.973183] [<ffffffff810f1cba>] ? balance_pgdat+0x56b/0x56b
> [ 1080.973187] [<ffffffff81071f69>] kthread+0xa8/0xb0
> [ 1080.973200] [<ffffffff814806b4>] kernel_thread_helper+0x4/0x10
> [ 1080.973205] [<ffffffff81071ec1>] ? __init_kthread_worker+0x5a/0x5a
> [ 1080.973210] [<ffffffff814806b0>] ? gs_change+0x13/0x13
> [ 1080.973213] no locks held by kswapd0/25.
>
> Signed-off-by: Peng Tao <peng_tao@emc.com>
> ---
> fs/nfs/blocklayout/blocklayout.c | 8 ++++++--
> 1 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
> index 0920c35..cc78e62 100644
> --- a/fs/nfs/blocklayout/blocklayout.c
> +++ b/fs/nfs/blocklayout/blocklayout.c
> @@ -533,6 +533,11 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync)
> fill_invalid_ext:
> dprintk("%s need to zero %d pages\n", __func__, npg_zero);
> for (;npg_zero > 0; npg_zero--) {
> + if (bl_is_sector_init(be->be_inval, isect)) {
> + dprintk("isect %llu already init\n",
> + (unsigned long long)isect);
> + goto next_page;
> + }
> /* page ref released in bl_end_io_write_zero */
> index = isect >> PAGE_CACHE_SECTOR_SHIFT;
> dprintk("%s zero %dth page: index %lu isect %llu\n",
> @@ -552,8 +557,7 @@ fill_invalid_ext:
> * PageUptodate: It was read before
> * sector_initialized: already written out
> */
> - if (PageDirty(page) || PageWriteback(page) ||
> - bl_is_sector_init(be->be_inval, isect)) {
> + if (PageDirty(page) || PageWriteback(page)) {
> print_page(page);
> unlock_page(page);
> page_cache_release(page);
> --
> 1.7.1.262.g5ef3d
>
>
--
Thanks,
-Bergwolf
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