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path: root/drivers/md/bcache/super.c
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Diffstat (limited to 'drivers/md/bcache/super.c')
-rw-r--r--drivers/md/bcache/super.c64
1 files changed, 51 insertions, 13 deletions
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 813b38aec3e4..2ea490b9d370 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -293,8 +293,7 @@ static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
bio->bi_iter.bi_sector = SB_SECTOR;
- __bio_add_page(bio, virt_to_page(out), SB_SIZE,
- offset_in_page(out));
+ bio_add_virt_nofail(bio, out, SB_SIZE);
out->offset = cpu_to_le64(sb->offset);
@@ -546,7 +545,8 @@ static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
static struct uuid_entry *uuid_find_empty(struct cache_set *c)
{
- static const char zero_uuid[16] = { 0 };
+ static const char zero_uuid[16] __nonstring =
+ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
return uuid_find(c, zero_uuid);
}
@@ -1733,7 +1733,12 @@ static CLOSURE_CALLBACK(cache_set_flush)
mutex_unlock(&b->write_lock);
}
- if (ca->alloc_thread)
+ /*
+ * If the register_cache_set() call to bch_cache_set_alloc() failed,
+ * ca has not been assigned a value and return error.
+ * So we need check ca is not NULL during bch_cache_set_unregister().
+ */
+ if (ca && ca->alloc_thread)
kthread_stop(ca->alloc_thread);
if (c->journal.cur) {
@@ -1907,7 +1912,8 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
INIT_LIST_HEAD(&c->btree_cache_freed);
INIT_LIST_HEAD(&c->data_buckets);
- iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) *
+ iter_size = sizeof(struct btree_iter) +
+ ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) *
sizeof(struct btree_iter_set);
c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
@@ -2233,15 +2239,47 @@ static int cache_alloc(struct cache *ca)
bio_init(&ca->journal.bio, NULL, ca->journal.bio.bi_inline_vecs, 8, 0);
/*
- * when ca->sb.njournal_buckets is not zero, journal exists,
- * and in bch_journal_replay(), tree node may split,
- * so bucket of RESERVE_BTREE type is needed,
- * the worst situation is all journal buckets are valid journal,
- * and all the keys need to replay,
- * so the number of RESERVE_BTREE type buckets should be as much
- * as journal buckets
+ * When the cache disk is first registered, ca->sb.njournal_buckets
+ * is zero, and it is assigned in run_cache_set().
+ *
+ * When ca->sb.njournal_buckets is not zero, journal exists,
+ * and in bch_journal_replay(), tree node may split.
+ * The worst situation is all journal buckets are valid journal,
+ * and all the keys need to replay, so the number of RESERVE_BTREE
+ * type buckets should be as much as journal buckets.
+ *
+ * If the number of RESERVE_BTREE type buckets is too few, the
+ * bch_allocator_thread() may hang up and unable to allocate
+ * bucket. The situation is roughly as follows:
+ *
+ * 1. In bch_data_insert_keys(), if the operation is not op->replace,
+ * it will call the bch_journal(), which increments the journal_ref
+ * counter. This counter is only decremented after bch_btree_insert
+ * completes.
+ *
+ * 2. When calling bch_btree_insert, if the btree needs to split,
+ * it will call btree_split() and btree_check_reserve() to check
+ * whether there are enough reserved buckets in the RESERVE_BTREE
+ * slot. If not enough, bcache_btree_root() will repeatedly retry.
+ *
+ * 3. Normally, the bch_allocator_thread is responsible for filling
+ * the reservation slots from the free_inc bucket list. When the
+ * free_inc bucket list is exhausted, the bch_allocator_thread
+ * will call invalidate_buckets() until free_inc is refilled.
+ * Then bch_allocator_thread calls bch_prio_write() once. and
+ * bch_prio_write() will call bch_journal_meta() and waits for
+ * the journal write to complete.
+ *
+ * 4. During journal_write, journal_write_unlocked() is be called.
+ * If journal full occurs, journal_reclaim() and btree_flush_write()
+ * will be called sequentially, then retry journal_write.
+ *
+ * 5. When 2 and 4 occur together, IO will hung up and cannot recover.
+ *
+ * Therefore, reserve more RESERVE_BTREE type buckets.
*/
- btree_buckets = ca->sb.njournal_buckets ?: 8;
+ btree_buckets = clamp_t(size_t, ca->sb.nbuckets >> 7,
+ 32, SB_JOURNAL_BUCKETS);
free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
if (!free) {
ret = -EPERM;