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authorKent Overstreet <kmo@daterainc.com>2013-09-23 23:17:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-24 14:41:43 -0700
commit84786438ed17978d72eeced580ab757e4da8830b (patch)
treec23d3b88414deb9b3c83a971fe78d8bac6485ccb
parenta698e08c82dfb9771e0bac12c7337c706d729b6d (diff)
bcache: Fix for handling overlapping extents when reading in a btree node
btree_sort_fixup() was overly clever, because it was trying to avoid pulling a key off the btree iterator in more than one place. This led to a really obscure bug where we'd break early from the loop in btree_sort_fixup() if the current key overlapped with keys in more than one older set, and the next key it overlapped with was zero size. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: linux-stable <stable@vger.kernel.org> # >= v3.10 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/md/bcache/bset.c39
1 files changed, 28 insertions, 11 deletions
diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 8010eed06a51..22d1ae72c282 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c
@@ -926,28 +926,45 @@ struct bkey *bch_next_recurse_key(struct btree *b, struct bkey *search)
/* Mergesort */
+static void sort_key_next(struct btree_iter *iter,
+ struct btree_iter_set *i)
+{
+ i->k = bkey_next(i->k);
+
+ if (i->k == i->end)
+ *i = iter->data[--iter->used];
+}
+
static void btree_sort_fixup(struct btree_iter *iter)
{
while (iter->used > 1) {
struct btree_iter_set *top = iter->data, *i = top + 1;
- struct bkey *k;
if (iter->used > 2 &&
btree_iter_cmp(i[0], i[1]))
i++;
- for (k = i->k;
- k != i->end && bkey_cmp(top->k, &START_KEY(k)) > 0;
- k = bkey_next(k))
- if (top->k > i->k)
- __bch_cut_front(top->k, k);
- else if (KEY_SIZE(k))
- bch_cut_back(&START_KEY(k), top->k);
-
- if (top->k < i->k || k == i->k)
+ if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0)
break;
- heap_sift(iter, i - top, btree_iter_cmp);
+ if (!KEY_SIZE(i->k)) {
+ sort_key_next(iter, i);
+ heap_sift(iter, i - top, btree_iter_cmp);
+ continue;
+ }
+
+ if (top->k > i->k) {
+ if (bkey_cmp(top->k, i->k) >= 0)
+ sort_key_next(iter, i);
+ else
+ bch_cut_front(top->k, i->k);
+
+ heap_sift(iter, i - top, btree_iter_cmp);
+ } else {
+ /* can't happen because of comparison func */
+ BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k)));
+ bch_cut_back(&START_KEY(i->k), top->k);
+ }
}
}