nfsd4: simplify stateid sequencing checks
Pull this common code into a separate function.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b73e96d..b83b58d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1975,6 +1975,26 @@
&& mandatory_lock(inode);
}
+static int check_stateid_generation(stateid_t *in, stateid_t *ref)
+{
+ /* If the client sends us a stateid from the future, it's buggy: */
+ if (in->si_generation > ref->si_generation)
+ return nfserr_bad_stateid;
+ /*
+ * The following, however, can happen. For example, if the
+ * client sends an open and some IO at the same time, the open
+ * may bump si_generation while the IO is still in flight.
+ * Thanks to hard links and renames, the client never knows what
+ * file an open will affect. So it could avoid that situation
+ * only by serializing all opens and IO from the same open
+ * owner. To recover from the old_stateid error, the client
+ * will just have to retry the IO:
+ */
+ if (in->si_generation < ref->si_generation)
+ return nfserr_old_stateid;
+ return nfs_ok;
+}
+
/*
* Checks for stateid operations
*/
@@ -2023,12 +2043,8 @@
goto out;
stidp = &stp->st_stateid;
}
- if (stateid->si_generation > stidp->si_generation)
- goto out;
-
- /* OLD STATEID */
- status = nfserr_old_stateid;
- if (stateid->si_generation < stidp->si_generation)
+ status = check_stateid_generation(stateid, stidp);
+ if (status)
goto out;
if (stp) {
if ((status = nfs4_check_openmode(stp,flags)))
@@ -2065,6 +2081,7 @@
{
struct nfs4_stateid *stp;
struct nfs4_stateowner *sop;
+ __be32 status;
dprintk("NFSD: preprocess_seqid_op: seqid=%d "
"stateid = (%08x/%08x/%08x/%08x)\n", seqid,
@@ -2150,15 +2167,9 @@
" confirmed yet!\n");
return nfserr_bad_stateid;
}
- if (stateid->si_generation > stp->st_stateid.si_generation) {
- dprintk("NFSD: preprocess_seqid_op: future stateid?!\n");
- return nfserr_bad_stateid;
- }
-
- if (stateid->si_generation < stp->st_stateid.si_generation) {
- dprintk("NFSD: preprocess_seqid_op: old stateid!\n");
- return nfserr_old_stateid;
- }
+ status = check_stateid_generation(stateid, &stp->st_stateid);
+ if (status)
+ return status;
renew_client(sop->so_client);
return nfs_ok;