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RAID5: check_reshape() shouldn't call mddev_suspend 

check_reshape() is called from raid5d thread. raid5d thread shouldn't
call mddev_suspend(), because mddev_suspend() waits for all IO finish
but IO is handled in raid5d thread, we could easily deadlock here.

This issue is introduced by
738a273 ("md/raid5: fix allocation of 'scribble' array.")

Cc: stable@vger.kernel.org (v4.1+)
Reported-and-tested-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
This commit is contained in:
Shaohua Li 2016-02-24 17:38:28 -08:00
parent e7597e69de
commit 27a353c026
2 changed files with 20 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/md/raid5.c
View File

@ -2089,6 +2089,14 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
unsigned long cpu; unsigned long cpu;
int err = 0; int err = 0;
/*
* Never shrink. And mddev_suspend() could deadlock if this is called
* from raid5d. In that case, scribble_disks and scribble_sectors
* should equal to new_disks and new_sectors
*/
if (conf->scribble_disks >= new_disks &&
conf->scribble_sectors >= new_sectors)
return 0;
mddev_suspend(conf->mddev); mddev_suspend(conf->mddev);
get_online_cpus(); get_online_cpus();
for_each_present_cpu(cpu) { for_each_present_cpu(cpu) {
@ -2110,6 +2118,10 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
} }
put_online_cpus(); put_online_cpus();
mddev_resume(conf->mddev); mddev_resume(conf->mddev);
if (!err) {
conf->scribble_disks = new_disks;
conf->scribble_sectors = new_sectors;
}
return err; return err;
} }
@ -6413,6 +6425,12 @@ static int raid5_alloc_percpu(struct r5conf *conf)
} }
put_online_cpus(); put_online_cpus();
if (!err) {
conf->scribble_disks = max(conf->raid_disks,
conf->previous_raid_disks);
conf->scribble_sectors = max(conf->chunk_sectors,
conf->prev_chunk_sectors);
}
return err; return err;
} }

2
drivers/md/raid5.h
View File

@ -510,6 +510,8 @@ struct r5conf {
* conversions * conversions
*/ */
} __percpu *percpu; } __percpu *percpu;
int scribble_disks;
int scribble_sectors;
#ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_HOTPLUG_CPU
struct notifier_block cpu_notify; struct notifier_block cpu_notify;
#endif #endif