nfsd: freeze c/mtime updates with outstanding WRITE_ATTRS delegation

Instead of allowing the ctime to roll backward with a WRITE_ATTRS
delegation, set FMODE_NOCMTIME on the file and have it skip mtime and
ctime updates.

It is possible that the client will never send a SETATTR to set the
times before returning the delegation. Add two new bools to struct
nfs4_delegation:

dl_written: tracks whether the file has been written since the
delegation was granted. This is set in the WRITE and LAYOUTCOMMIT
handlers.

dl_setattr: tracks whether the client has sent at least one valid
mtime that can also update the ctime in a SETATTR.

When unlocking the lease for the delegation, clear FMODE_NOCMTIME. If
the file has been written, but no setattr for the delegated mtime and
ctime has been done, update the timestamps to current_time().

Suggested-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index aacd912a5fbe29ba5ccac206d13243308f36b7fa..bfebe6e25638a76d3607bb79a239bdc92e42e7b5 100644 (file)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1151,7 +1151,9 @@ vet_deleg_attrs(struct nfsd4_setattr *setattr, struct nfs4_delegation *dp)
        if (setattr->sa_bmval[2] & FATTR4_WORD2_TIME_DELEG_MODIFY) {
                if (nfsd4_vet_deleg_time(&iattr->ia_mtime, &dp->dl_mtime, &now)) {
                        iattr->ia_ctime = iattr->ia_mtime;
-                       if (!nfsd4_vet_deleg_time(&iattr->ia_ctime, &dp->dl_ctime, &now))
+                       if (nfsd4_vet_deleg_time(&iattr->ia_ctime, &dp->dl_ctime, &now))
+                               dp->dl_setattr = true;
+                       else
                                iattr->ia_valid &= ~(ATTR_CTIME | ATTR_CTIME_SET);
                } else {
                        iattr->ia_valid &= ~(ATTR_CTIME | ATTR_CTIME_SET |
@@ -1238,12 +1240,26 @@ out:
        return status;
 }
 
+static void nfsd4_file_mark_deleg_written(struct nfs4_file *fi)
+{
+       spin_lock(&fi->fi_lock);
+       if (!list_empty(&fi->fi_delegations)) {
+               struct nfs4_delegation *dp = list_first_entry(&fi->fi_delegations,
+                                                             struct nfs4_delegation, dl_perfile);
+
+               if (dp->dl_type == OPEN_DELEGATE_WRITE_ATTRS_DELEG)
+                       dp->dl_written = true;
+       }
+       spin_unlock(&fi->fi_lock);
+}
+
 static __be32
 nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
            union nfsd4_op_u *u)
 {
        struct nfsd4_write *write = &u->write;
        stateid_t *stateid = &write->wr_stateid;
+       struct nfs4_stid *stid = NULL;
        struct nfsd_file *nf = NULL;
        __be32 status = nfs_ok;
        unsigned long cnt;
@@ -1256,10 +1272,15 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
        trace_nfsd_write_start(rqstp, &cstate->current_fh,
                               write->wr_offset, cnt);
        status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
-                                               stateid, WR_STATE, &nf, NULL);
+                                               stateid, WR_STATE, &nf, &stid);
        if (status)
                return status;
 
+       if (stid) {
+               nfsd4_file_mark_deleg_written(stid->sc_file);
+               nfs4_put_stid(stid);
+       }
+
        write->wr_how_written = write->wr_stable_how;
        status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,
                                write->wr_offset, &write->wr_payload,
@@ -2550,6 +2571,7 @@ nfsd4_layoutcommit(struct svc_rqst *rqstp,
        mutex_unlock(&ls->ls_mutex);
 
        nfserr = ops->proc_layoutcommit(inode, rqstp, lcp);
+       nfsd4_file_mark_deleg_written(ls->ls_stid.sc_file);
        nfs4_put_stid(&ls->ls_stid);
 out:
        return nfserr;

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 205ee8cc6fa2b9f74d08f7938b323d03bdf8286c..81fa7cc6c77b3cdc5ff22bc60ab0654f95dc258d 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1222,6 +1222,42 @@ static void put_deleg_file(struct nfs4_file *fp)
                nfs4_file_put_access(fp, NFS4_SHARE_ACCESS_READ);
 }
 
+static void nfsd4_finalize_deleg_timestamps(struct nfs4_delegation *dp, struct file *f)
+{
+       struct iattr ia = { .ia_valid = ATTR_ATIME | ATTR_CTIME | ATTR_MTIME };
+       struct inode *inode = file_inode(f);
+       int ret;
+
+       /* don't do anything if FMODE_NOCMTIME isn't set */
+       if ((READ_ONCE(f->f_mode) & FMODE_NOCMTIME) == 0)
+               return;
+
+       spin_lock(&f->f_lock);
+       f->f_mode &= ~FMODE_NOCMTIME;
+       spin_unlock(&f->f_lock);
+
+       /* was it never written? */
+       if (!dp->dl_written)
+               return;
+
+       /* did it get a setattr for the timestamps at some point? */
+       if (dp->dl_setattr)
+               return;
+
+       /* Stamp everything to "now" */
+       inode_lock(inode);
+       ret = notify_change(&nop_mnt_idmap, f->f_path.dentry, &ia, NULL);
+       inode_unlock(inode);
+       if (ret) {
+               struct inode *inode = file_inode(f);
+
+               pr_notice_ratelimited("Unable to update timestamps on inode %02x:%02x:%lu: %d\n",
+                                       MAJOR(inode->i_sb->s_dev),
+                                       MINOR(inode->i_sb->s_dev),
+                                       inode->i_ino, ret);
+       }
+}
+
 static void nfs4_unlock_deleg_lease(struct nfs4_delegation *dp)
 {
        struct nfs4_file *fp = dp->dl_stid.sc_file;
@@ -1229,6 +1265,7 @@ static void nfs4_unlock_deleg_lease(struct nfs4_delegation *dp)
 
        WARN_ON_ONCE(!fp->fi_delegees);
 
+       nfsd4_finalize_deleg_timestamps(dp, nf->nf_file);
        kernel_setlease(nf->nf_file, F_UNLCK, NULL, (void **)&dp);
        put_deleg_file(fp);
 }
@@ -6265,6 +6302,8 @@ nfs4_open_delegation(struct svc_rqst *rqstp, struct nfsd4_open *open,
        memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
 
        if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
+               struct file *f = dp->dl_stid.sc_file->fi_deleg_file->nf_file;
+
                if (!nfsd4_add_rdaccess_to_wrdeleg(rqstp, open, fh, stp) ||
                                !nfs4_delegation_stat(dp, currentfh, &stat)) {
                        nfs4_put_stid(&dp->dl_stid);
@@ -6278,6 +6317,9 @@ nfs4_open_delegation(struct svc_rqst *rqstp, struct nfsd4_open *open,
                dp->dl_atime = stat.atime;
                dp->dl_ctime = stat.ctime;
                dp->dl_mtime = stat.mtime;
+               spin_lock(&f->f_lock);
+               f->f_mode |= FMODE_NOCMTIME;
+               spin_unlock(&f->f_lock);
                trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
        } else {
                open->op_delegate_type = deleg_ts && nfs4_delegation_stat(dp, currentfh, &stat) ?

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index bf9436cdb93c5dd5502ecf83433ea311e3678711..b6ac0f37e9cdfcfddde5861c8c0c51bad60101b7 100644 (file)
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -217,10 +217,12 @@ struct nfs4_delegation {
        struct nfs4_clnt_odstate *dl_clnt_odstate;
        time64_t                dl_time;
        u32                     dl_type;
-/* For recall: */
+       /* For recall: */
        int                     dl_retries;
        struct nfsd4_callback   dl_recall;
        bool                    dl_recalled;
+       bool                    dl_written;
+       bool                    dl_setattr;
 
        /* for CB_GETATTR */
        struct nfs4_cb_fattr    dl_cb_fattr;