Btrfs: avoid sleeping in verify_parent_transid while atomic
verify_parent_transid needs to lock the extent range to make
sure no IO is underway, and so it can safely clear the
uptodate bits if our checks fail.
But, a few callers are using it with spinlocks held. Most
of the time, the generation numbers are going to match, and
we don't want to switch to a blocking lock just for the error
case. This adds an atomic flag to verify_parent_transid,
and changes it to return EAGAIN if it needs to block to
properly verifiy things.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 6fc2e6f..49fd7b6 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6568,7 +6568,7 @@
goto skip;
}
- if (!btrfs_buffer_uptodate(next, generation)) {
+ if (!btrfs_buffer_uptodate(next, generation, 0)) {
btrfs_tree_unlock(next);
free_extent_buffer(next);
next = NULL;
