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authorSong Liu <songliubraving@fb.com>2017-05-11 17:03:44 -0700
committerShaohua Li <shli@fb.com>2017-05-11 22:14:40 -0700
commit5ddf0440a1a28f00f69ed2e093476bab3b60c2c3 (patch)
tree33a11155215f93288b40d300839a58f3c13b7f8c /drivers/md
parent70d466f760b351fe30b5f8c956354ddf29aa676b (diff)
md/r5cache: handle sync with data in write back cache
Currently, sync of raid456 array cannot make progress when hitting data in writeback r5cache. This patch fixes this issue by flushing cached data of the stripe before processing the sync request. This is achived by: 1. In handle_stripe(), do not set STRIPE_SYNCING if the stripe is in write back cache; 2. In r5c_try_caching_write(), handle the stripe in sync with write through; 3. In do_release_stripe(), make stripe in sync write out and send it to the state machine. Shaohua: explictly set STRIPE_HANDLE after write out completed Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/raid5-cache.c8
-rw-r--r--drivers/md/raid5.c21
2 files changed, 22 insertions, 7 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index cc3f8442f11f..4c00bc248287 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -2637,8 +2637,11 @@ int r5c_try_caching_write(struct r5conf *conf,
* When run in degraded mode, array is set to write-through mode.
* This check helps drain pending write safely in the transition to
* write-through mode.
+ *
+ * When a stripe is syncing, the write is also handled in write
+ * through mode.
*/
- if (s->failed) {
+ if (s->failed || test_bit(STRIPE_SYNCING, &sh->state)) {
r5c_make_stripe_write_out(sh);
return -EAGAIN;
}
@@ -2841,6 +2844,9 @@ void r5c_finish_stripe_write_out(struct r5conf *conf,
}
r5l_append_flush_payload(log, sh->sector);
+ /* stripe is flused to raid disks, we can do resync now */
+ if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
+ set_bit(STRIPE_HANDLE, &sh->state);
}
int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 0ac57a925606..9c4f7659f8b1 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -233,11 +233,15 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
if (test_bit(R5_InJournal, &sh->dev[i].flags))
injournal++;
/*
- * When quiesce in r5c write back, set STRIPE_HANDLE for stripes with
- * data in journal, so they are not released to cached lists
+ * In the following cases, the stripe cannot be released to cached
+ * lists. Therefore, we make the stripe write out and set
+ * STRIPE_HANDLE:
+ * 1. when quiesce in r5c write back;
+ * 2. when resync is requested fot the stripe.
*/
- if (conf->quiesce && r5c_is_writeback(conf->log) &&
- !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0) {
+ if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
+ (conf->quiesce && r5c_is_writeback(conf->log) &&
+ !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
if (test_bit(STRIPE_R5C_CACHING, &sh->state))
r5c_make_stripe_write_out(sh);
set_bit(STRIPE_HANDLE, &sh->state);
@@ -4656,8 +4660,13 @@ static void handle_stripe(struct stripe_head *sh)
if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
spin_lock(&sh->stripe_lock);
- /* Cannot process 'sync' concurrently with 'discard' */
- if (!test_bit(STRIPE_DISCARD, &sh->state) &&
+ /*
+ * Cannot process 'sync' concurrently with 'discard'.
+ * Flush data in r5cache before 'sync'.
+ */
+ if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
+ !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
+ !test_bit(STRIPE_DISCARD, &sh->state) &&
test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
set_bit(STRIPE_SYNCING, &sh->state);
clear_bit(STRIPE_INSYNC, &sh->state);