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authorSong Liu <songliubraving@fb.com>2017-01-24 10:45:30 -0800
committerShaohua Li <shli@fb.com>2017-01-24 11:26:06 -0800
commit2e38a37f23c98d7fad87ff022670060b8a0e2bf5 (patch)
tree0cc010718f63769debe1e45f7ff20bffc6db0b88 /drivers/md/raid5.h
parent07e83364845e1e1c7e189a01206a9d7d33831568 (diff)
md/r5cache: disable write back for degraded array
write-back cache in degraded mode introduces corner cases to the array. Although we try to cover all these corner cases, it is safer to just disable write-back cache when the array is in degraded mode. In this patch, we disable writeback cache for degraded mode: 1. On device failure, if the array enters degraded mode, raid5_error() will submit async job r5c_disable_writeback_async to disable writeback; 2. In r5c_journal_mode_store(), it is invalid to enable writeback in degraded mode; 3. In r5c_try_caching_write(), stripes with s->failed>0 will be handled in write-through mode. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5.h')
-rw-r--r--drivers/md/raid5.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 461df197d157..1440fa26e296 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -758,6 +758,7 @@ extern sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
extern struct stripe_head *
raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
int previous, int noblock, int noquiesce);
+extern int raid5_calc_degraded(struct r5conf *conf);
extern int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev);
extern void r5l_exit_log(struct r5l_log *log);
extern int r5l_write_stripe(struct r5l_log *log, struct stripe_head *head_sh);
@@ -786,4 +787,5 @@ extern void r5c_flush_cache(struct r5conf *conf, int num);
extern void r5c_check_stripe_cache_usage(struct r5conf *conf);
extern void r5c_check_cached_full_stripe(struct r5conf *conf);
extern struct md_sysfs_entry r5c_journal_mode;
+extern void r5c_update_on_rdev_error(struct mddev *mddev);
#endif