[PATCH 4.4 04/74] btrfs: Fix no_space in write and rm loop

Greg Kroah-Hartman
2016-03-08T00:24:01Z

From: Zhao Lei <zhaolei@cn.fujitsu.com>

commit e1746e8381cd2af421f75557b5cae3604fc18b35 upstream.

I see no_space in v4.4-rc1 again in xfstests generic/102.
It happened randomly in some node only.
(one of 4 phy-node, and a kvm with non-virtio block driver)

By bisect, we can found the first-bad is:
commit bdced438acd8 ("block: setup bi_phys_segments after splitting")'
But above patch only triggered the bug by making bio operation
faster(or slower).

Main reason is in our space_allocating code, we need to commit
page writeback before wait it complish, this patch fixed above
bug.

BTW, there is another reason for generic/102 fail, caused by
disable default mixed-blockgroup, I'll fix it in xfstests.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/extent-tree.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4086,8 +4086,10 @@ commit_trans:
!atomic_read(&root->fs_info->open_ioctl_trans)) {
need_commit--;

- if (need_commit > 0)
+ if (need_commit > 0) {
+ btrfs_start_delalloc_roots(fs_info, 0, -1);
btrfs_wait_ordered_roots(fs_info, -1);
+ }

trans = btrfs_join_transaction(root);
if (IS_ERR(trans))