Since superblock is updated infrequently, we do a simple trim of log
disk (a synchronous trim)
Signed-off-by: Shaohua Li <shli@xxxxxx>
---
drivers/md/raid5-cache.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index caeec10..5dbe084 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -85,6 +85,7 @@ struct r5l_log {
spinlock_t no_space_stripes_lock;
bool need_cache_flush;
+ bool in_teardown;
};
/*
@@ -644,6 +645,60 @@ void r5l_flush_stripe_to_raid(struct r5l_log *log)
}
static void r5l_write_super(struct r5l_log *log, sector_t cp);
+static void r5l_write_super_and_discard_space(struct r5l_log *log,
+ sector_t end)
+{
+ struct block_device *bdev = log->rdev->bdev;
+ struct mddev *mddev;
+
+ r5l_write_super(log, end);
+
+ if (!blk_queue_discard(bdev_get_queue(bdev)))
+ return;
+
+ mddev = log->rdev->mddev;
+ /*
+ * This is to avoid a deadlock. r5l_quiesce holds reconfig_mutex and
+ * wait for this thread to finish. This thread waits for
+ * MD_CHANGE_PENDING clear, which is supposed to be done in
+ * md_check_recovery(). md_check_recovery() tries to get
+ * reconfig_mutex. Since r5l_quiesce already holds the mutex,
+ * md_check_recovery() fails, so the PENDING never get cleared. The
+ * in_teardown check workaround this issue.
+ * */
+ if (!log->in_teardown) {
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ set_bit(MD_CHANGE_PENDING, &mddev->flags);
+ md_wakeup_thread(mddev->thread);
+ wait_event(mddev->sb_wait,
+ !test_bit(MD_CHANGE_PENDING, &mddev->flags) ||
+ log->in_teardown);
+ /*
+ * r5l_quiesce could run after in_teardown check and hold
+ * mutex first. Superblock might get updated twice.
+ * */
+ if (log->in_teardown)
+ md_update_sb(mddev, 1);
+ } else {
+ BUG_ON(!mddev_is_locked(mddev));
+ md_update_sb(mddev, 1);
+ }
+
+ if (log->last_checkpoint < end) {
+ blkdev_issue_discard(bdev,
+ log->last_checkpoint + log->rdev->data_offset,
+ end - log->last_checkpoint, GFP_NOIO, 0);
+ } else {
+ blkdev_issue_discard(bdev,
+ log->last_checkpoint + log->rdev->data_offset,
+ log->device_size - log->last_checkpoint,
+ GFP_NOIO, 0);
+ blkdev_issue_discard(bdev, log->rdev->data_offset, end,
+ GFP_NOIO, 0);
+ }
+}
+
+
static void r5l_do_reclaim(struct r5l_log *log)
{
sector_t reclaim_target = xchg(&log->reclaim_target, 0);
@@ -685,7 +740,7 @@ static void r5l_do_reclaim(struct r5l_log *log)
* here, because the log area might be reused soon and we don't want to
* confuse recovery
*/
- r5l_write_super(log, next_checkpoint);
+ r5l_write_super_and_discard_space(log, next_checkpoint);
mutex_lock(&log->io_mutex);
log->last_checkpoint = next_checkpoint;
@@ -721,9 +776,11 @@ static void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
void r5l_quiesce(struct r5l_log *log, int state)
{
+ struct mddev *mddev;
if (!log || state == 2)
return;
if (state == 0) {
+ log->in_teardown = 0;
log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
log->rdev->mddev, "reclaim");
} else if (state == 1) {
@@ -731,6 +788,10 @@ void r5l_quiesce(struct r5l_log *log, int state)
* at this point all stripes are finished, so io_unit is at
* least in STRIPE_END state
*/
+ log->in_teardown = 1;
+ /* make sure r5l_write_super_and_discard_space exits */
+ mddev = log->rdev->mddev;
+ wake_up(&mddev->sb_wait);
r5l_wake_reclaim(log, -1L);
md_unregister_thread(&log->reclaim_thread);
r5l_do_reclaim(log);
--
2.4.6
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