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authorSong Liu <songliubraving@fb.com>2017-05-11 15:28:28 -0700
committerShaohua Li <shli@fb.com>2017-05-11 22:11:11 -0700
commit70d466f760b351fe30b5f8c956354ddf29aa676b (patch)
tree1e9cb8b69fb904173cb9fcf7d900c3be4bc91ab3 /drivers/md/raid5-cache.c
parent23b245c04d0ef408087430dd4d1b214a5da1eb78 (diff)
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md/r5cache: gracefully handle journal device errors for writeback mode
For the raid456 with writeback cache, when journal device failed during normal operation, it is still possible to persist all data, as all pending data is still in stripe cache. However, it is necessary to handle journal failure gracefully. During journal failures, the following logic handles the graceful shutdown of journal: 1. raid5_error() marks the device as Faulty and schedules async work log->disable_writeback_work; 2. In disable_writeback_work (r5c_disable_writeback_async), the mddev is suspended, set to write through, and then resumed. mddev_suspend() flushes all cached stripes; 3. All cached stripes need to be flushed carefully to the RAID array. This patch fixes issues within the process above: 1. In r5c_update_on_rdev_error() schedule disable_writeback_work for journal failures; 2. In r5c_disable_writeback_async(), wait for MD_SB_CHANGE_PENDING, since raid5_error() updates superblock. 3. In handle_stripe(), allow stripes with data in journal (s.injournal > 0) to make progress during log_failed; 4. In delay_towrite(), if log failed only process data in the cache (skip new writes in dev->towrite); 5. In __get_priority_stripe(), process loprio_list during journal device failures. 6. In raid5_remove_disk(), wait for all cached stripes are flushed before calling log_exit(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5-cache.c')
-rw-r--r--drivers/md/raid5-cache.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index a6a62e212cd3..cc3f8442f11f 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -24,6 +24,7 @@
#include "md.h"
#include "raid5.h"
#include "bitmap.h"
+#include "raid5-log.h"
/*
* metadata/data stored in disk with 4k size unit (a block) regardless
@@ -680,6 +681,11 @@ static void r5c_disable_writeback_async(struct work_struct *work)
return;
pr_info("md/raid:%s: Disabling writeback cache for degraded array.\n",
mdname(mddev));
+
+ /* wait superblock change before suspend */
+ wait_event(mddev->sb_wait,
+ !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
+
mddev_suspend(mddev);
log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
mddev_resume(mddev);
@@ -2983,7 +2989,7 @@ ioerr:
return ret;
}
-void r5c_update_on_rdev_error(struct mddev *mddev)
+void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
{
struct r5conf *conf = mddev->private;
struct r5l_log *log = conf->log;
@@ -2991,7 +2997,8 @@ void r5c_update_on_rdev_error(struct mddev *mddev)
if (!log)
return;
- if (raid5_calc_degraded(conf) > 0 &&
+ if ((raid5_calc_degraded(conf) > 0 ||
+ test_bit(Journal, &rdev->flags)) &&
conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK)
schedule_work(&log->disable_writeback_work);
}