Messages in this thread |  | | From | Olga Kornievskaia <> | | Date | Tue, 7 Apr 2026 09:28:28 -0400 | | Subject | Re: [PATCH v2 1/2] nfs: fix utimensat() for atime with delegated timestamps |
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Hi Jeff and all,
With this patch and running against a server that would update the c/mtime of a GETATTR in a compound with CLONE(COPY), the timestamps is (might be) going "backwards"? I see that SETATTR+DELEGRETURN (after the CLONE) is setting a timestamp which is earlier than what's returned by the server in the GETATTR. Though I haven't figured out how to "show" it via test (I observe it on a network trace).
This is seen testing either against Hammerspace which already updates the values or the linux server with the patch I'm working on to update timestamp for CLONE/COPY.
I have to say I haven't figured out if this patch needs to modify such that it fixes 221 but doesn't break 407 or we are fundamentally dealing with a problem of including a GETATTR in a compound while holding an attribute delegation that needs to be solved differently. Like I said before, if the server were to update the value upon receiving the GETATTR in the compound (regardless of the origin), should it then do a CB_GETATTR first (which I already grumbled seems like a poor choice)? Or, should the client be changed to not send a GETATTR in CLONE of the compounds if it's holding an attribute delegation and somehow figure out attributes differently then it does now.
On Wed, Mar 25, 2026 at 8:30 AM Jeff Layton <jlayton@kernel.org> wrote: > > On Tue, 2026-03-24 at 13:32 -0400, Jeff Layton wrote: > > xfstest generic/221 is failing with delegated timestamps enabled. When > > the client holds a WRITE_ATTRS_DELEG delegation, and a userland process > > does a utimensat() for only the atime, the ctime is not properly > > updated. The problem is that the client tries to cache the atime update, > > but there is no mtime update, so the delegated attribute update never > > updates the ctime. > > > > Delegated timestamps don't have a mechanism to update the ctime in > > accordance with atime-only changes due to utimensat() and the like. > > Change the client to issue an RPC in this case, so that the ctime gets > > properly updated alongside the atime. > > > > Fixes: 40f45ab3814f ("NFS: Further fixes to attribute delegation a/mtime changes") > > Reported-by: Olga Kornievskaia <aglo@umich.edu> > > Signed-off-by: Jeff Layton <jlayton@kernel.org> > > --- > > fs/nfs/inode.c | 9 +-------- > > 1 file changed, 1 insertion(+), 8 deletions(-) > > > > diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c > > index 4786343eeee0f874aa1f31ace2f35fdcb83fc7a6..3a5bba7e3c92d4d4fcd65234cd2f10e56f78dee0 100644 > > --- a/fs/nfs/inode.c > > +++ b/fs/nfs/inode.c > > @@ -757,14 +757,7 @@ nfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry, > > } else if (nfs_have_delegated_atime(inode) && > > attr->ia_valid & ATTR_ATIME && > > !(attr->ia_valid & ATTR_MTIME)) { > > - if (attr->ia_valid & ATTR_ATIME_SET) { > > - if (uid_eq(task_uid, owner_uid)) { > > - spin_lock(&inode->i_lock); > > - nfs_set_timestamps_to_ts(inode, attr); > > - spin_unlock(&inode->i_lock); > > - attr->ia_valid &= ~(ATTR_ATIME|ATTR_ATIME_SET); > > - } > > - } else { > > This probably deserves a comment. How about something like: > > /* > * An atime-only update via an explicit setattr (e.g.: utimensat() and > * the like) requires updating the ctime as well. Delegated timestamps > * don't have a mechanism for updating the ctime with a delegated > * atime-only update, so an RPC must be issued. > */ > > > + if (!(attr->ia_valid & ATTR_ATIME_SET)) { > > nfs_update_delegated_atime(inode); > > attr->ia_valid &= ~ATTR_ATIME; > > } > > -- > Jeff Layton <jlayton@kernel.org>
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