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/tree-log.c b/fs/btrfs/tree-log.c
index d017283..eb1ae90 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -279,7 +279,7 @@
log->fs_info->extent_root,
eb->start, eb->len);
- if (btrfs_buffer_uptodate(eb, gen)) {
+ if (btrfs_buffer_uptodate(eb, gen, 0)) {
if (wc->write)
btrfs_write_tree_block(eb);
if (wc->wait)
