[PATCH] Btrfs: deal with error on secondary log properly

[Josef Bacik <jbacik@fb.com>]

If we have an fsync at the same time in two seperate subvolumes we could end up
with the tree log pointing at invalid blocks.  We need to notice if our writeout
failed in anyway, if it did then we need to do a full transaction commit and
return an error on the subvolume that gave us the io error.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
---
 fs/btrfs/file.c     | 4 ++++
 fs/btrfs/tree-log.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index b823fac..c8f49f5 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2054,6 +2054,10 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 			if (!ret) {
 				ret = btrfs_end_transaction(trans, root);
 				goto out;
+			} else if (ctx.io_err) {
+				btrfs_end_transaction(trans, root);
+				ret = ctx.io_err;
+				goto out;
 			}
 		}
 		if (!full_sync) {
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 1bbaace..b4f15f5 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2857,6 +2857,10 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 		ret = btrfs_wait_marked_extents(log, &log->dirty_log_pages,
 						mark);
 		btrfs_wait_logged_extents(trans, log, log_transid);
+		if (ret) {
+			btrfs_set_log_full_commit(root->fs_info, trans);
+			ctx->io_err = ret;
+		}
 		wait_log_commit(log_root_tree,
 				root_log_ctx.log_transid);
 		mutex_unlock(&log_root_tree->log_mutex);
-- 
2.1.0