commit 8b5fc0540dee82c3b3de7dc84d4c4e591fdca91b Author: Arkadiusz Miśkiewicz <ar...@maven.pl> Date: Sat Dec 29 01:29:21 2018 +0100
- rel 2; fix raid10 lockup on resync/raid check kernel-small_fixes.patch | 124 +++++++++++++++++++++++++++++++++++++++++++++++ kernel.spec | 2 +- 2 files changed, 125 insertions(+), 1 deletion(-) --- diff --git a/kernel.spec b/kernel.spec index 28ef9700..f8ca7ac4 100644 --- a/kernel.spec +++ b/kernel.spec @@ -67,7 +67,7 @@ %define have_pcmcia 0 %endif -%define rel 1 +%define rel 2 %define basever 4.20 %define postver .0 diff --git a/kernel-small_fixes.patch b/kernel-small_fixes.patch index b97c7aaf..63bd4794 100644 --- a/kernel-small_fixes.patch +++ b/kernel-small_fixes.patch @@ -38,3 +38,127 @@ index 584cf2d..aea3bc2 100644 /* version 5 superblocks support inode version counters. */ if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5) +From e820d55cb99dd93ac2dc949cf486bb187e5cd70d Mon Sep 17 00:00:00 2001 +From: Guoqing Jiang <gqji...@suse.com> +Date: Wed, 19 Dec 2018 14:19:25 +0800 +Subject: md: fix raid10 hang issue caused by barrier +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +When both regular IO and resync IO happen at the same time, +and if we also need to split regular. Then we can see tasks +hang due to barrier. + +1. resync thread +[ 1463.757205] INFO: task md1_resync:5215 blocked for more than 480 seconds. +[ 1463.757207] Not tainted 4.19.5-1-default #1 +[ 1463.757209] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. +[ 1463.757212] md1_resync D 0 5215 2 0x80000000 +[ 1463.757216] Call Trace: +[ 1463.757223] ? __schedule+0x29a/0x880 +[ 1463.757231] ? raise_barrier+0x8d/0x140 [raid10] +[ 1463.757236] schedule+0x78/0x110 +[ 1463.757243] raise_barrier+0x8d/0x140 [raid10] +[ 1463.757248] ? wait_woken+0x80/0x80 +[ 1463.757257] raid10_sync_request+0x1f6/0x1e30 [raid10] +[ 1463.757265] ? _raw_spin_unlock_irq+0x22/0x40 +[ 1463.757284] ? is_mddev_idle+0x125/0x137 [md_mod] +[ 1463.757302] md_do_sync.cold.78+0x404/0x969 [md_mod] +[ 1463.757311] ? wait_woken+0x80/0x80 +[ 1463.757336] ? md_rdev_init+0xb0/0xb0 [md_mod] +[ 1463.757351] md_thread+0xe9/0x140 [md_mod] +[ 1463.757358] ? _raw_spin_unlock_irqrestore+0x2e/0x60 +[ 1463.757364] ? __kthread_parkme+0x4c/0x70 +[ 1463.757369] kthread+0x112/0x130 +[ 1463.757374] ? kthread_create_worker_on_cpu+0x40/0x40 +[ 1463.757380] ret_from_fork+0x3a/0x50 + +2. regular IO +[ 1463.760679] INFO: task kworker/0:8:5367 blocked for more than 480 seconds. +[ 1463.760683] Not tainted 4.19.5-1-default #1 +[ 1463.760684] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. +[ 1463.760687] kworker/0:8 D 0 5367 2 0x80000000 +[ 1463.760718] Workqueue: md submit_flushes [md_mod] +[ 1463.760721] Call Trace: +[ 1463.760731] ? __schedule+0x29a/0x880 +[ 1463.760741] ? wait_barrier+0xdd/0x170 [raid10] +[ 1463.760746] schedule+0x78/0x110 +[ 1463.760753] wait_barrier+0xdd/0x170 [raid10] +[ 1463.760761] ? wait_woken+0x80/0x80 +[ 1463.760768] raid10_write_request+0xf2/0x900 [raid10] +[ 1463.760774] ? wait_woken+0x80/0x80 +[ 1463.760778] ? mempool_alloc+0x55/0x160 +[ 1463.760795] ? md_write_start+0xa9/0x270 [md_mod] +[ 1463.760801] ? try_to_wake_up+0x44/0x470 +[ 1463.760810] raid10_make_request+0xc1/0x120 [raid10] +[ 1463.760816] ? wait_woken+0x80/0x80 +[ 1463.760831] md_handle_request+0x121/0x190 [md_mod] +[ 1463.760851] md_make_request+0x78/0x190 [md_mod] +[ 1463.760860] generic_make_request+0x1c6/0x470 +[ 1463.760870] raid10_write_request+0x77a/0x900 [raid10] +[ 1463.760875] ? wait_woken+0x80/0x80 +[ 1463.760879] ? mempool_alloc+0x55/0x160 +[ 1463.760895] ? md_write_start+0xa9/0x270 [md_mod] +[ 1463.760904] raid10_make_request+0xc1/0x120 [raid10] +[ 1463.760910] ? wait_woken+0x80/0x80 +[ 1463.760926] md_handle_request+0x121/0x190 [md_mod] +[ 1463.760931] ? _raw_spin_unlock_irq+0x22/0x40 +[ 1463.760936] ? finish_task_switch+0x74/0x260 +[ 1463.760954] submit_flushes+0x21/0x40 [md_mod] + +So resync io is waiting for regular write io to complete to +decrease nr_pending (conf->barrier++ is called before waiting). +The regular write io splits another bio after call wait_barrier +which call nr_pending++, then the splitted bio would continue +with raid10_write_request -> wait_barrier, so the splitted bio +has to wait for barrier to be zero, then deadlock happens as +follows. + + resync io regular io + + raise_barrier + wait_barrier + generic_make_request + wait_barrier + +To resolve the issue, we need to call allow_barrier to decrease +nr_pending before generic_make_request since regular IO is not +issued to underlying devices, and wait_barrier is called again +to ensure no internal IO happening. + +Fixes: fc9977dd069e ("md/raid10: simplify the splitting of requests.") +Reported-and-tested-by: Siniša Bandin <sin...@4net.rs> +Signed-off-by: Guoqing Jiang <gqji...@suse.com> +Signed-off-by: Shaohua Li <s...@fb.com> +--- + drivers/md/raid10.c | 4 ++++ + 1 file changed, 4 insertions(+) + +diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c +index 76c92e31afc0..abb5d382f64d 100644 +--- a/drivers/md/raid10.c ++++ b/drivers/md/raid10.c +@@ -1209,7 +1209,9 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio, + struct bio *split = bio_split(bio, max_sectors, + gfp, &conf->bio_split); + bio_chain(split, bio); ++ allow_barrier(conf); + generic_make_request(bio); ++ wait_barrier(conf); + bio = split; + r10_bio->master_bio = bio; + r10_bio->sectors = max_sectors; +@@ -1492,7 +1494,9 @@ retry_write: + struct bio *split = bio_split(bio, r10_bio->sectors, + GFP_NOIO, &conf->bio_split); + bio_chain(split, bio); ++ allow_barrier(conf); + generic_make_request(bio); ++ wait_barrier(conf); + bio = split; + r10_bio->master_bio = bio; + } +-- +cgit 1.2-0.3.lf.el7 + ================================================================ ---- gitweb: http://git.pld-linux.org/gitweb.cgi/packages/kernel.git/commitdiff/8b5fc0540dee82c3b3de7dc84d4c4e591fdca91b _______________________________________________ pld-cvs-commit mailing list pld-cvs-commit@lists.pld-linux.org http://lists.pld-linux.org/mailman/listinfo/pld-cvs-commit