Re: [PATCH v2 3/7] nfsd: use ATTR_CTIME_SET for delegated ctime updates

Jeff Layton
2025-07-26T22:25:45Z

On Sat, 2025-07-26 at 15:57 -0400, Chuck Lever wrote:
> On 7/26/25 3:03 PM, Jeff Layton wrote:
> > On Sat, 2025-07-26 at 14:48 -0400, Chuck Lever wrote:
> > > Hi Jeff -
> > >
> > > Thanks again for your focus on getting this straightened out!
> > >
> > >
> > > On 7/26/25 10:31 AM, Jeff Layton wrote:
> > > > Ensure that notify_change() doesn't clobber a delegated ctime update
> > > > with current_time() by setting ATTR_CTIME_SET for those updates.
> > > >
> > > > Also, set the tv_nsec field the nfsd4_decode_fattr4 to the correct
> > > > value.
> > >
> > > I don't yet see the connection of the above tv_nsec fix to the other
> > > changes in this patch. Wouldn't this be an independent fix?
> > >
> >
> > I felt like they were related. Yes, the ia_ctime field is currently
> > being set wrong, but it's also being clobbered by notify_change(), so
> > it doesn't matter much. I can break this into a separate patch (with a
> > Fixes: tag) if you prefer though.
>
> Ah, got it, this patch exposes a latent bug. The usual thing to do is to
> fix the latent bug in a preceding/pre-requisite patch, so that's my
> preference.
>

OK. I'll plan to send a v3 set.

>
> > > > Don't bother setting the timestamps in cb_getattr_update_times() in the
> > > > non-delegated case. notify_change() will do that itself.
> > > >
> > > > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > >
> > > General comments:
> > >
> > > I don't feel that any of the patches in this series need to be tagged
> > > for stable, since there is already a Kconfig setting that defaults to
> > > leaving timestamp delegation disabled. But I would like to see Fixes:
> > > tags, where that makes sense?
> > >
> >
> > I don't think any of these need to go to stable since this is still
> > under a non-default Kconfig option, and the main effect of the bug is
> > wonky timestamps. I should be able to add some Fixes: tags though.
> >
> > > Is this set on top of the set you posted a day or two ago with the new
> > > trace point? Or does this set replace that one?
> > >
> >
> > This set should replace those.
>
> I was confused because the trace point patch is missing, and dropping it
> wasn't mentioned in the cover letter's Change log. NBD, thanks for
> clarifying.
>

Ahh sorry. The last patch drops the function to which I was adding the
tracepoint, so I dropped the tracepoint as well.

> Since the bulk of these are NFSD changes, I volunteer to take v3 once
> we have Acks from the VFS maintainers, as needed.
>

Many thanks!

>
> > > > ---
> > > > fs/nfsd/nfs4state.c | 6 +++---
> > > > fs/nfsd/nfs4xdr.c | 5 +++--
> > > > 2 files changed, 6 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > > > index 88c347957da5b8f352be63f84f207d2225f81cb9..77eea2ad93cc07939f045fc4b983b1ac00d068b8 100644
> > > > --- a/fs/nfsd/nfs4state.c
> > > > +++ b/fs/nfsd/nfs4state.c
> > > > @@ -9167,7 +9167,6 @@ static bool set_cb_time(struct timespec64 *cb, const struct timespec64 *orig,
> > > > static int cb_getattr_update_times(struct dentry *dentry, struct nfs4_delegation *dp)
> > > > {
> > > > struct inode *inode = d_inode(dentry);
> > > > - struct timespec64 now = current_time(inode);
> > > > struct nfs4_cb_fattr *ncf = &dp->dl_cb_fattr;
> > > > struct iattr attrs = { };
> > > > int ret;
> > > > @@ -9175,6 +9174,7 @@ static int cb_getattr_update_times(struct dentry *dentry, struct nfs4_delegation
> > > > if (deleg_attrs_deleg(dp->dl_type)) {
> > > > struct timespec64 atime = inode_get_atime(inode);
> > > > struct timespec64 mtime = inode_get_mtime(inode);
> > > > + struct timespec64 now = current_time(inode);
> > > >
> > > > attrs.ia_atime = ncf->ncf_cb_atime;
> > > > attrs.ia_mtime = ncf->ncf_cb_mtime;
> > > > @@ -9183,12 +9183,12 @@ static int cb_getattr_update_times(struct dentry *dentry, struct nfs4_delegation
> > > > attrs.ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
> > > >
> > > > if (set_cb_time(&attrs.ia_mtime, &mtime, &now)) {
> > > > - attrs.ia_valid |= ATTR_CTIME | ATTR_MTIME | ATTR_MTIME_SET;
> > > > + attrs.ia_valid |= ATTR_CTIME | ATTR_CTIME_SET |
> > > > + ATTR_MTIME | ATTR_MTIME_SET;
> > > > attrs.ia_ctime = attrs.ia_mtime;
> > > > }
> > > > } else {
> > > > attrs.ia_valid |= ATTR_MTIME | ATTR_CTIME;
> > > > - attrs.ia_mtime = attrs.ia_ctime = now;
> > > > }
> > > >
> > > > if (!attrs.ia_valid)
> > > > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> > > > index 8b68f74a8cf08c6aa1305a2a3093467656085e4a..c0a3c6a7c8bb70d62940115c3101e9f897401456 100644
> > > > --- a/fs/nfsd/nfs4xdr.c
> > > > +++ b/fs/nfsd/nfs4xdr.c
> > > > @@ -538,8 +538,9 @@ nfsd4_decode_fattr4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen,
> > > > iattr->ia_mtime.tv_sec = modify.seconds;
> > > > iattr->ia_mtime.tv_nsec = modify.nseconds;
> > > > iattr->ia_ctime.tv_sec = modify.seconds;
> > > > - iattr->ia_ctime.tv_nsec = modify.seconds;
> > > > - iattr->ia_valid |= ATTR_CTIME | ATTR_MTIME | ATTR_MTIME_SET | ATTR_DELEG;
> > > > + iattr->ia_ctime.tv_nsec = modify.nseconds;
> > > > + iattr->ia_valid |= ATTR_CTIME | ATTR_CTIME_SET |
> > > > + ATTR_MTIME | ATTR_MTIME_SET | ATTR_DELEG;
> > > > }
> > > >
> > > > /* request sanity: did attrlist4 contain the expected number of words? */
> > > >
> > >
> > >
> >
>

--
Jeff Layton <jlayton@kernel.org>