| From c426c4fd46f709ade2bddd51c5738729c7ae1db5 Mon Sep 17 00:00:00 2001 |
| From: Kent Overstreet <kmo@daterainc.com> |
| Date: Mon, 23 Sep 2013 23:17:29 -0700 |
| Subject: bcache: Fix for when no journal entries are found |
| |
| From: Kent Overstreet <kmo@daterainc.com> |
| |
| commit c426c4fd46f709ade2bddd51c5738729c7ae1db5 upstream. |
| |
| The journal replay code didn't handle this case, causing it to go into |
| an infinite loop... |
| |
| Signed-off-by: Kent Overstreet <kmo@daterainc.com> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/md/bcache/journal.c | 30 ++++++++++++++++++------------ |
| 1 file changed, 18 insertions(+), 12 deletions(-) |
| |
| --- a/drivers/md/bcache/journal.c |
| +++ b/drivers/md/bcache/journal.c |
| @@ -151,7 +151,8 @@ int bch_journal_read(struct cache_set *c |
| 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++) { |
| @@ -164,18 +165,20 @@ int bch_journal_read(struct cache_set *c |
| 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); |
| @@ -195,10 +198,12 @@ bsearch: |
| 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) { |
| @@ -226,9 +231,10 @@ bsearch: |
| } |
| } |
| |
| - c->journal.seq = list_entry(list->prev, |
| - struct journal_replay, |
| - list)->j.seq; |
| + if (!list_empty(list)) |
| + c->journal.seq = list_entry(list->prev, |
| + struct journal_replay, |
| + list)->j.seq; |
| |
| return 0; |
| #undef read_bucket |
