From bc9389eefe479b7b7b323c2729b61a7155d2d0ea Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Tue, 10 Sep 2013 19:07:35 -0700 Subject: [PATCH] bcache: Avoid deadlocking in garbage collection Not a complete fix - we could still deadlock if btree_insert_node() has to split... Signed-off-by: Kent Overstreet --- drivers/md/bcache/btree.c | 21 +++++++++++---------- drivers/md/bcache/btree.h | 2 +- drivers/md/bcache/super.c | 2 +- 3 files changed, 13 insertions(+), 12 deletions(-) diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 7d283d2..bf8f517 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -1059,14 +1059,14 @@ static void btree_node_free(struct btree *b) mutex_unlock(&b->c->bucket_lock); } -struct btree *bch_btree_node_alloc(struct cache_set *c, int level) +struct btree *bch_btree_node_alloc(struct cache_set *c, int level, bool wait) { BKEY_PADDED(key) k; struct btree *b = ERR_PTR(-EAGAIN); mutex_lock(&c->bucket_lock); retry: - if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, true)) + if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, wait)) goto err; bkey_put(c, &k.key); @@ -1098,9 +1098,9 @@ err: return b; } -static struct btree *btree_node_alloc_replacement(struct btree *b) +static struct btree *btree_node_alloc_replacement(struct btree *b, bool wait) { - struct btree *n = bch_btree_node_alloc(b->c, b->level); + struct btree *n = bch_btree_node_alloc(b->c, b->level, wait); if (!IS_ERR_OR_NULL(n)) bch_btree_sort_into(b, n); @@ -1250,7 +1250,7 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op, return 0; for (i = 0; i < nodes; i++) { - new_nodes[i] = btree_node_alloc_replacement(r[i].b); + new_nodes[i] = btree_node_alloc_replacement(r[i].b, false); if (IS_ERR_OR_NULL(new_nodes[i])) goto out_nocoalesce; } @@ -1420,7 +1420,8 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op, if (!IS_ERR(last->b)) { should_rewrite = btree_gc_mark_node(last->b, gc); if (should_rewrite) { - n = btree_node_alloc_replacement(last->b); + n = btree_node_alloc_replacement(last->b, + false); if (!IS_ERR_OR_NULL(n)) { bch_btree_node_write_sync(n); @@ -1492,7 +1493,7 @@ static int bch_btree_gc_root(struct btree *b, struct btree_op *op, should_rewrite = btree_gc_mark_node(b, gc); if (should_rewrite) { - n = btree_node_alloc_replacement(b); + n = btree_node_alloc_replacement(b, false); if (!IS_ERR_OR_NULL(n)) { bch_btree_node_write_sync(n); @@ -2038,7 +2039,7 @@ static int btree_split(struct btree *b, struct btree_op *op, closure_init_stack(&cl); - n1 = btree_node_alloc_replacement(b); + n1 = btree_node_alloc_replacement(b, true); if (IS_ERR(n1)) goto err; @@ -2049,12 +2050,12 @@ static int btree_split(struct btree *b, struct btree_op *op, trace_bcache_btree_node_split(b, n1->sets[0].data->keys); - n2 = bch_btree_node_alloc(b->c, b->level); + n2 = bch_btree_node_alloc(b->c, b->level, true); if (IS_ERR(n2)) goto err_free1; if (!b->parent) { - n3 = bch_btree_node_alloc(b->c, b->level + 1); + n3 = bch_btree_node_alloc(b->c, b->level + 1, true); if (IS_ERR(n3)) goto err_free2; } diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h index b5a46af..767e755 100644 --- a/drivers/md/bcache/btree.h +++ b/drivers/md/bcache/btree.h @@ -271,7 +271,7 @@ void bch_btree_node_read(struct btree *); void bch_btree_node_write(struct btree *, struct closure *); void bch_btree_set_root(struct btree *); -struct btree *bch_btree_node_alloc(struct cache_set *, int); +struct btree *bch_btree_node_alloc(struct cache_set *, int, bool); struct btree *bch_btree_node_get(struct cache_set *, struct bkey *, int, bool); int bch_btree_insert_check_key(struct btree *, struct btree_op *, diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 7ab926d..e21200e 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1601,7 +1601,7 @@ static void run_cache_set(struct cache_set *c) goto err; err = "cannot allocate new btree root"; - c->root = bch_btree_node_alloc(c, 0); + c->root = bch_btree_node_alloc(c, 0, true); if (IS_ERR_OR_NULL(c->root)) goto err; -- 2.7.4