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Commit c426c4fd authored by Kent Overstreet's avatar Kent Overstreet Committed by Linus Torvalds
Browse files

bcache: Fix for when no journal entries are found 



The journal replay code didn't handle this case, causing it to go into
an infinite loop...

Signed-off-by: default avatarKent Overstreet <kmo@daterainc.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v3.10
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent aee6f1cf

drivers/md/bcache/journal.c

+18 −12
Original line number Diff line number Diff line
@@ -153,7 +153,8 @@ int bch_journal_read(struct cache_set *c, struct list_head *list, 
		bitmap_zero(bitmap, SB_JOURNAL_BUCKETS);

		pr_debug("%u journal buckets", ca->sb.njournal_buckets);



		/* Read journal buckets ordered by golden ratio hash to quickly

		/*

		 * Read journal buckets ordered by golden ratio hash to quickly

		 * find a sequence of buckets with valid journal entries

		 */

		for (i = 0; i < ca->sb.njournal_buckets; i++) {
@@ -166,18 +167,20 @@ int bch_journal_read(struct cache_set *c, struct list_head *list, 
				goto bsearch;

		}



		/* If that fails, check all the buckets we haven't checked

		/*

		 * If that fails, check all the buckets we haven't checked

		 * already

		 */

		pr_debug("falling back to linear search");



		for (l = 0; l < ca->sb.njournal_buckets; l++) {

			if (test_bit(l, bitmap))

				continue;



		for (l = find_first_zero_bit(bitmap, ca->sb.njournal_buckets);

		     l < ca->sb.njournal_buckets;

		     l = find_next_zero_bit(bitmap, ca->sb.njournal_buckets, l + 1))

			if (read_bucket(l))

				goto bsearch;

		}



		if (list_empty(list))

			continue;

bsearch:

		/* Binary search */

		m = r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);
@@ -197,10 +200,12 @@ int bch_journal_read(struct cache_set *c, struct list_head *list, 
				r = m;

		}



		/* Read buckets in reverse order until we stop finding more

		/*

		 * Read buckets in reverse order until we stop finding more

		 * journal entries

		 */

		pr_debug("finishing up");

		pr_debug("finishing up: m %u njournal_buckets %u",

			 m, ca->sb.njournal_buckets);

		l = m;



		while (1) {
@@ -228,6 +233,7 @@ int bch_journal_read(struct cache_set *c, struct list_head *list, 
			}

	}



	if (!list_empty(list))

		c->journal.seq = list_entry(list->prev,

					    struct journal_replay,

					    list)->j.seq;