Re: [PATCH v6 11/16] xfs: Check for -ENOATTR or -EEXIST

Allison Collins
2020-01-22T04:29:22Z

On 1/21/20 4:15 PM, Darrick J. Wong wrote:
> On Sat, Jan 18, 2020 at 03:50:30PM -0700, Allison Collins wrote:
>> Delayed operations cannot return error codes. So we must check for
>> these conditions first before starting set or remove operations
>
> Answering my own question from earlier -- I see here you actually /are/
> checking the attr existence w.r.t. ATTR_{CREATE,REPLACE} right after we
> allocate a transaction and ILOCK the inode, so
>
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Alrighty, thank you!

>
> Though I am wondering if you could discard the predicates from the
> second patch in favor of doing a normal lookup of the attr with a zero
> valuelen to determine if there's already an attribute?
I think I likely answered this in the response to that patch. Because
it's used as part of the remove procedures, we still need it. We could
make a simpler version just for this application I suppose, but it seems
like it'd just be extra code since we still need the former.

Thank you for the reviews!
Allison

>
> --D
>
>> Signed-off-by: Allison Collins <allison.henderson@oracle.com>
>> ---
>> fs/xfs/libxfs/xfs_attr.c | 12 ++++++++++++
>> 1 file changed, 12 insertions(+)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>> index a2673fe..e9d22c1 100644
>> --- a/fs/xfs/libxfs/xfs_attr.c
>> +++ b/fs/xfs/libxfs/xfs_attr.c
>> @@ -457,6 +457,14 @@ xfs_attr_set(
>> goto out_trans_cancel;
>>
>> xfs_trans_ijoin(args.trans, dp, 0);
>> +
>> + error = xfs_has_attr(&args);
>> + if (error == -EEXIST && (name->type & ATTR_CREATE))
>> + goto out_trans_cancel;
>> +
>> + if (error == -ENOATTR && (name->type & ATTR_REPLACE))
>> + goto out_trans_cancel;
>> +
>> error = xfs_attr_set_args(&args);
>> if (error)
>> goto out_trans_cancel;
>> @@ -545,6 +553,10 @@ xfs_attr_remove(
>> */
>> xfs_trans_ijoin(args.trans, dp, 0);
>>
>> + error = xfs_has_attr(&args);
>> + if (error != -EEXIST)
>> + goto out;
>> +
>> error = xfs_attr_remove_args(&args);
>> if (error)
>> goto out;
>> --
>> 2.7.4
>>