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bcache: Journal replay fix

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The journal replay code starts by finding something that looks like a
valid journal entry, then it does a binary search over the unchecked
region of the journal for the journal entries with the highest sequence
numbers.

Trouble is, the logic was wrong - journal_read_bucket() returns true if
it found journal entries we need, but if the range of journal entries
we're looking for loops around the end of the journal - in that case
journal_read_bucket() could return true when it hadn't found the highest
sequence number we'd seen yet, and in that case the binary search did
the wrong thing. Whoops.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v3.10
This commit is contained in:
Kent Overstreet 2013-07-11 22:42:14 -07:00
parent 5caa52afc5
commit faa5673617
1 changed files with 7 additions and 2 deletions
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9
drivers/md/bcache/journal.c
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@ -184,9 +184,14 @@ bsearch:
pr_debug("starting binary search, l %u r %u", l, r); pr_debug("starting binary search, l %u r %u", l, r);
while (l + 1 < r) { while (l + 1 < r) {
m = (l + r) >> 1; seq = list_entry(list->prev, struct journal_replay,
list)->j.seq;
if (read_bucket(m)) m = (l + r) >> 1;
read_bucket(m);
if (seq != list_entry(list->prev, struct journal_replay,
list)->j.seq)
l = m; l = m;
else else
r = m; r = m;