Commit 84786438 authored by Kent Overstreet's avatar Kent Overstreet Committed by Linus Torvalds

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: default avatarKent Overstreet <>
Cc: linux-stable <> # >= v3.10
Signed-off-by: default avatarLinus Torvalds <>
parent a698e08c
......@@ -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]))
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)
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);
if (top->k > i->k) {
if (bkey_cmp(top->k, i->k) >= 0)
sort_key_next(iter, i);
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);
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