Btrfs: exclude logged extents before replying when we are mixed

With non-mixed block groups we replay the logs before we're allowed to do any
writes, so we get away with not pinning/removing the data extents until right
when we replay them.  However with mixed block groups we allocate out of the
same pool, so we could easily allocate a metadata block that was logged in our
tree log.  To deal with this we just need to notice that we have mixed block
groups and do the normal excluding/removal dance during the pin stage of the log
replay and that way we don't allocate metadata blocks from areas we have logged
data extents.  With this patch we now pass xfstests generic/311 with mixed
block groups turned on.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 831ddd4bf89..2c679149363 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -280,11 +280,23 @@ static int process_one_buffer(struct btrfs_root *log,
 {
 	int ret = 0;
 
+	/*
+	 * If this fs is mixed then we need to be able to process the leaves to
+	 * pin down any logged extents, so we have to read the block.
+	 */
+	if (btrfs_fs_incompat(log->fs_info, MIXED_GROUPS)) {
+		ret = btrfs_read_buffer(eb, gen);
+		if (ret)
+			return ret;
+	}
+
 	if (wc->pin)
 		ret = btrfs_pin_extent_for_log_replay(log->fs_info->extent_root,
 						      eb->start, eb->len);
 
 	if (!ret && btrfs_buffer_uptodate(eb, gen, 0)) {
+		if (wc->pin && btrfs_header_level(eb) == 0)
+			ret = btrfs_exclude_logged_extents(log, eb);
 		if (wc->write)
 			btrfs_write_tree_block(eb);
 		if (wc->wait)