Btrfs: add flushoncommit mount option
The 'flushoncommit' mount option forces any data dirtied by a write in a
prior transaction to commit as part of the current commit. This makes
the committed state a fully consistent view of the file system from the
application's perspective (i.e., it includes all completed file system
operations). This was previously the behavior only when a snapshot is
created.
This is used by Ceph to ensure that completed writes make it to the
platter along with the metadata operations they are bound to (by
BTRFS_IOC_TRANS_{START,END}).
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 3e8225d..2869b33 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -972,6 +972,7 @@
int ret;
int should_grow = 0;
unsigned long now = get_seconds();
+ int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
btrfs_run_ordered_operations(root, 0);
@@ -1051,7 +1052,9 @@
mutex_unlock(&root->fs_info->trans_mutex);
- if (snap_pending) {
+ if (flush_on_commit || snap_pending) {
+ if (flush_on_commit)
+ btrfs_start_delalloc_inodes(root);
ret = btrfs_wait_ordered_extents(root, 1);
BUG_ON(ret);
}