On Wed, Jan 3, 2018 at 5:41 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> On Wed, 2018-01-03 at 17:14 +0200, Amir Goldstein wrote:
>> The time values in stat and inode may differ for overlayfs and stat time
>> values are the correct ones to use. This is also consistent with the fact
>> that fill_post_wcc() also stores stat time values.
>>
>> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
>> ---
>> fs/nfsd/nfs3xdr.c | 31 ++++++++++++++++++++++++++++++-
>> fs/nfsd/nfs4xdr.c | 2 +-
>> fs/nfsd/nfsfh.h | 28 ++++++----------------------
>> 3 files changed, 37 insertions(+), 24 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
>> index 2758480555fa..1a70581e1cb2 100644
>> --- a/fs/nfsd/nfs3xdr.c
>> +++ b/fs/nfsd/nfs3xdr.c
>> @@ -251,6 +251,34 @@ encode_wcc_data(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)
>> }
>>
>> /*
>> + * Fill in the pre_op attr for the wcc data
>> + */
>> +void fill_pre_wcc(struct svc_fh *fhp)
>> +{
>> + struct inode *inode;
>> + struct kstat stat;
>> + __be32 err;
>> +
>> + if (fhp->fh_pre_saved)
>> + return;
>> +
>> + inode = d_inode(fhp->fh_dentry);
>> + err = fh_getattr(fhp, &stat);
>> + if (err) {
>> + /* Grab the times from inode anyway */
>> + stat.mtime = inode->i_mtime;
>> + stat.ctime = inode->i_ctime;
>> + stat.size = inode->i_size;
>> + }
>> +
>
> Might be best to instead just not supply pre/post op attrs if the
> getattr fails? They are technically optional with v3 -- we can just set
> the attributes_follow bit to false there.
I considered to set fh_pre_saved = false on error just like
fill_post_wcc() does, but wasn't sure of the consequences or how to test
for that matter, so I chose a more delicate fallback instead.
>
> For v4, it's a little more complicated. Scraping it out of the inode
> might be necessary for the cases where we need a change_info4.
>
> Either way, it'd be good to know that these getattrs are failing if this
> occurs. Maybe a KERN_WARNING printk or something might be good there?
>
As you wish, but fill_post_wcc() does not emit a warning, so...
I'll wait for feedback from Bruce as well.
Let me know the error handing of your choice.
Thanks,
Amir.
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