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-rw-r--r--drivers/md/dm-cache-target.c86
1 files changed, 53 insertions, 33 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 8785134c9f1f..0b7edfd0b454 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1201,6 +1201,18 @@ static void background_work_end(struct cache *cache)
/*----------------------------------------------------------------*/
+static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
+{
+ return (bio_data_dir(bio) == WRITE) &&
+ (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
+}
+
+static bool optimisable_bio(struct cache *cache, struct bio *bio, dm_oblock_t block)
+{
+ return writeback_mode(&cache->features) &&
+ (is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio));
+}
+
static void quiesce(struct dm_cache_migration *mg,
void (*continuation)(struct work_struct *))
{
@@ -1474,13 +1486,51 @@ static void mg_upgrade_lock(struct work_struct *ws)
}
}
+static void mg_full_copy(struct work_struct *ws)
+{
+ struct dm_cache_migration *mg = ws_to_mg(ws);
+ struct cache *cache = mg->cache;
+ struct policy_work *op = mg->op;
+ bool is_policy_promote = (op->op == POLICY_PROMOTE);
+
+ if ((!is_policy_promote && !is_dirty(cache, op->cblock)) ||
+ is_discarded_oblock(cache, op->oblock)) {
+ mg_upgrade_lock(ws);
+ return;
+ }
+
+ init_continuation(&mg->k, mg_upgrade_lock);
+
+ if (copy(mg, is_policy_promote)) {
+ DMERR_LIMIT("%s: migration copy failed", cache_device_name(cache));
+ mg->k.input = BLK_STS_IOERR;
+ mg_complete(mg, false);
+ }
+}
+
static void mg_copy(struct work_struct *ws)
{
- int r;
struct dm_cache_migration *mg = ws_to_mg(ws);
if (mg->overwrite_bio) {
/*
+ * No exclusive lock was held when we last checked if the bio
+ * was optimisable. So we have to check again in case things
+ * have changed (eg, the block may no longer be discarded).
+ */
+ if (!optimisable_bio(mg->cache, mg->overwrite_bio, mg->op->oblock)) {
+ /*
+ * Fallback to a real full copy after doing some tidying up.
+ */
+ bool rb = bio_detain_shared(mg->cache, mg->op->oblock, mg->overwrite_bio);
+ BUG_ON(rb); /* An exclussive lock must _not_ be held for this block */
+ mg->overwrite_bio = NULL;
+ inc_io_migrations(mg->cache);
+ mg_full_copy(ws);
+ return;
+ }
+
+ /*
* It's safe to do this here, even though it's new data
* because all IO has been locked out of the block.
*
@@ -1489,26 +1539,8 @@ static void mg_copy(struct work_struct *ws)
*/
overwrite(mg, mg_update_metadata_after_copy);
- } else {
- struct cache *cache = mg->cache;
- struct policy_work *op = mg->op;
- bool is_policy_promote = (op->op == POLICY_PROMOTE);
-
- if ((!is_policy_promote && !is_dirty(cache, op->cblock)) ||
- is_discarded_oblock(cache, op->oblock)) {
- mg_upgrade_lock(ws);
- return;
- }
-
- init_continuation(&mg->k, mg_upgrade_lock);
-
- r = copy(mg, is_policy_promote);
- if (r) {
- DMERR_LIMIT("%s: migration copy failed", cache_device_name(cache));
- mg->k.input = BLK_STS_IOERR;
- mg_complete(mg, false);
- }
- }
+ } else
+ mg_full_copy(ws);
}
static int mg_lock_writes(struct dm_cache_migration *mg)
@@ -1748,18 +1780,6 @@ static void inc_miss_counter(struct cache *cache, struct bio *bio)
/*----------------------------------------------------------------*/
-static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
-{
- return (bio_data_dir(bio) == WRITE) &&
- (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
-}
-
-static bool optimisable_bio(struct cache *cache, struct bio *bio, dm_oblock_t block)
-{
- return writeback_mode(&cache->features) &&
- (is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio));
-}
-
static int map_bio(struct cache *cache, struct bio *bio, dm_oblock_t block,
bool *commit_needed)
{