At 09/01/2016 08:54 AM, Liu Bo wrote:
On Thu, Sep 01, 2016 at 08:32:00AM +0800, Qu Wenruo wrote:
At 09/01/2016 07:43 AM, Liu Bo wrote:
Qgroup function may overwrite the saved error 'err' with 0
in case quota is not enabled, and this ends up with a
endless loop in balance because we keep going back to balance
the same block group.
In which case?
If join_trans() fails, we won't go through qgroup fix.
And before join_trans(), they all go to out_free/out tag.
Nothing to do with qgroup fix.
I don't think so.
It doesn't always go to out_free, in the while() loop, it'd break the
loop on any error and record it in @err, then go through
prepare_to_merge() + merge_reloc_roots() and other stuff.
Here's an example for keeping err after the above while loop(),
...
err = prepare_to_merge(rc, err);
...
OK, that's right.
Reviewed-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
While IMHO it's a larger problem that we didn't handle the error
immediately after prepare_to_merge() or inside the while(1) loop, but
postpone it to later parts.
Thanks,
Qu
Thanks,
-liubo
And if we hit qgroup_fix_relocated_data_extents(), then 'err' is alreayd 0,
nothing we need to save.
And even for quota disabled case, qgroup_fix_relocated_data_extents() will
just return 0. Nothing wrong at all.
Or did I miss something?
Thanks,
Qu
It really should use 'ret' instead.
Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
---
fs/btrfs/relocation.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 8a2c2a0..c0c13dc 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4200,9 +4200,11 @@ restart:
err = PTR_ERR(trans);
goto out_free;
}
- err = qgroup_fix_relocated_data_extents(trans, rc);
- if (err < 0) {
- btrfs_abort_transaction(trans, err);
+ ret = qgroup_fix_relocated_data_extents(trans, rc);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, ret);
+ if (!err)
+ err = ret;
goto out_free;
}
btrfs_commit_transaction(trans, rc->extent_root);
--
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