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.
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?
> + fhp->fh_pre_mtime = stat.mtime;
> + fhp->fh_pre_ctime = stat.ctime;
> + fhp->fh_pre_size = stat.size;
> + fhp->fh_pre_change = nfsd4_change_attribute(&stat, inode);
> + fhp->fh_pre_saved = true;
> +}
> +
> +/*
> * Fill in the post_op attr for the wcc data
> */
> void fill_post_wcc(struct svc_fh *fhp)
> @@ -261,7 +289,8 @@ void fill_post_wcc(struct svc_fh *fhp)
> printk("nfsd: inode locked twice during operation.\n");
>
> err = fh_getattr(fhp, &fhp->fh_post_attr);
> - fhp->fh_post_change = nfsd4_change_attribute(d_inode(fhp->fh_dentry));
> + fhp->fh_post_change = nfsd4_change_attribute(&fhp->fh_post_attr,
> + d_inode(fhp->fh_dentry));
> if (err) {
> fhp->fh_post_saved = false;
> /* Grab the ctime anyway - set_change_info might use it */
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 2c61c6b8ae09..fbe11ad9b9ff 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -1991,7 +1991,7 @@ static __be32 *encode_change(__be32 *p, struct kstat *stat, struct inode *inode,
> *p++ = cpu_to_be32(convert_to_wallclock(exp->cd->flush_time));
> *p++ = 0;
> } else if (IS_I_VERSION(inode)) {
> - p = xdr_encode_hyper(p, nfsd4_change_attribute(inode));
> + p = xdr_encode_hyper(p, nfsd4_change_attribute(stat, inode));
> } else {
> *p++ = cpu_to_be32(stat->ctime.tv_sec);
> *p++ = cpu_to_be32(stat->ctime.tv_nsec);
> diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
> index 43f31cf49bae..99be87b50ebe 100644
> --- a/fs/nfsd/nfsfh.h
> +++ b/fs/nfsd/nfsfh.h
> @@ -252,36 +252,20 @@ fh_clear_wcc(struct svc_fh *fhp)
> * By using both ctime and the i_version counter we guarantee that as
> * long as time doesn't go backwards we never reuse an old value.
> */
> -static inline u64 nfsd4_change_attribute(struct inode *inode)
> +static inline u64 nfsd4_change_attribute(struct kstat *stat,
> + struct inode *inode)
> {
> u64 chattr;
>
> - chattr = inode->i_ctime.tv_sec;
> + chattr = stat->ctime.tv_sec;
> chattr <<= 30;
> - chattr += inode->i_ctime.tv_nsec;
> + chattr += stat->ctime.tv_nsec;
> chattr += inode->i_version;
> return chattr;
> }
>
> -/*
> - * Fill in the pre_op attr for the wcc data
> - */
> -static inline void
> -fill_pre_wcc(struct svc_fh *fhp)
> -{
> - struct inode *inode;
> -
> - inode = d_inode(fhp->fh_dentry);
> - if (!fhp->fh_pre_saved) {
> - fhp->fh_pre_mtime = inode->i_mtime;
> - fhp->fh_pre_ctime = inode->i_ctime;
> - fhp->fh_pre_size = inode->i_size;
> - fhp->fh_pre_change = nfsd4_change_attribute(inode);
> - fhp->fh_pre_saved = true;
> - }
> -}
> -
> -extern void fill_post_wcc(struct svc_fh *);
> +extern void fill_pre_wcc(struct svc_fh *fhp);
> +extern void fill_post_wcc(struct svc_fh *fhp);
> #else
> #define fh_clear_wcc(ignored)
> #define fill_pre_wcc(ignored)
--
Jeff Layton <jlayton@xxxxxxxxxx>
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