From: Kent Overstreet <kent.overstreet@gmail.com>
Date: Wed, 18 Sep 2019 23:33:12 +0000 (-0400)
Subject: bcachefs: Avoid deadlocking on the allocator
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4d13e818f5c00ae064aefba8349383cc2d79bf6d;p=linux.git

bcachefs: Avoid deadlocking on the allocator

The allocator needs to make sure there's buckets available on the
RESERVE_NONE freelist if at all possible - otherwise foreground IO will
get stuck.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index 54051161eba76..85795b580892d 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -1164,7 +1164,7 @@ static int bch2_allocator_thread(void *arg)
 			 */
 			if (!nr ||
 			    (nr < ALLOC_SCAN_BATCH(ca) &&
-			     !fifo_full(&ca->free[RESERVE_MOVINGGC]))) {
+			     !fifo_empty(&ca->free[RESERVE_NONE]))) {
 				ret = wait_buckets_available(c, ca);
 				if (ret) {
 					up_read(&c->gc_lock);