[PATCH 21/21] btrfs: make state preallocation more speculative in __set_extent_bit

David Sterba
2016-06-03T15:43:34Z

commit 059f791c6bbaba72dc3c1bd6e2657aacc8552849 upstream.

Similar to __clear_extent_bit, do not fail if the state preallocation
fails as we might not need it. One less BUG_ON.

Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/extent_io.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 57fccc420697..b5ff48d6a0c5 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -875,8 +875,14 @@ __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
bits |= EXTENT_FIRST_DELALLOC;
again:
if (!prealloc && gfpflags_allow_blocking(mask)) {
+ /*
+ * Don't care for allocation failure here because we might end
+ * up not needing the pre-allocated extent state at all, which
+ * is the case if we only have in the tree extent states that
+ * cover our input range and don't cover too any other range.
+ * If we end up needing a new extent state we allocate it later.
+ */
prealloc = alloc_extent_state(mask);
- BUG_ON(!prealloc);
}

spin_lock(&tree->lock);
--
2.7.1