On 03/03/2015 10:12 PM, Liu Bo wrote:
On Tue, Mar 03, 2015 at 05:35:33PM +0100, David Sterba wrote:
On Tue, Mar 03, 2015 at 07:02:58PM +0800, Liu Bo wrote:
On Mon, Mar 02, 2015 at 12:46:55PM -0500, Josef Bacik wrote:
Dave could hit this assert consistently running btrfs/078. This is because
when we update the block groups we could truncate the free space, which would
try to delete the csums for that range and dirty the csum root. For this to
happen we have to have already written out the csum root so it's kind of hard to
hit this case. This patch fixes this by changing the logic to only write the
dirty block groups if the dirty_cowonly_roots list is empty. This will get us
the same effect as before since we add the extent root last, and will cover the
case that we dirty some other root again but not the extent root. Thanks,
Free space inode is NODATASUM, so its searching csum tree in
__btrfs_free_extent() is really unnecessary, by skipping that, csum tree
won't be inserted into dirty_cowonly_roots list again, so it also passed btrfs/078,
at least on my box.
I can hit the bug [1] even with Josef's patch, I'm can test your fix if you
want.
MKFS_OPTIONS -- -O skinny-metadata,extref -m single -d single --mixed /dev/sdc1
MOUNT_OPTIONS -- -o enospc_debug,space_cache,noatime /dev/sdc1 /mnt/a2
on top of 3.19-rc5 with Chris' for-linus.
I tested this fix on top of 4.0.0-rc1 which has the same commits with
Chris's for-linus, I looply ran btrfs/078 for 10 times(5 times with the
default mkfs option while 5 with your mkfs option), works good so far.
So here it is,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 571f402..111380c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6033,7 +6033,7 @@ static int __btrfs_free_extent(struct
btrfs_trans_handle *trans,
}
btrfs_release_path(path);
- if (is_data) {
+ if (is_data && root_objectid != BTRFS_ROOT_TREE_OBJECTID) {
ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, extent_root, ret);
I have this locally but it was causing problems with xfstests (or
there's unrelated problems that I just haven't noticed before), so I
didn't send it out yet. My patch _should_ have fixed the problem, so if
it didn't I want to figure out why before we go fixing other things.
Thanks,
Josef
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