NFSv4: Use the open stateid if the delegation has the wrong mode

Fix nfs4_select_rw_stateid() so that it chooses the open stateid
(or an all-zero stateid) if the delegation does not match the selected
read/write mode.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 7 insertions, 1 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 7ef19ce6d832..553a83cc4106 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -144,6 +144,7 @@ struct nfs4_lock_state {
 enum {
         LK_STATE_IN_USE,
         NFS_DELEGATED_STATE,            /* Current stateid is delegation */
+        NFS_OPEN_STATE,                 /* OPEN stateid is set */
         NFS_O_RDONLY_STATE,             /* OPEN stateid has read-only state */
         NFS_O_WRONLY_STATE,             /* OPEN stateid has write-only state */
         NFS_O_RDWR_STATE,               /* OPEN stateid has read/write state */
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 282d9fa6994a..39849360f9f6 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -978,6 +978,7 @@ static void nfs_set_open_stateid_locked(struct nfs4_state *state, nfs4_stateid *
         if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                 nfs4_stateid_copy(&state->stateid, stateid);
         nfs4_stateid_copy(&state->open_stateid, stateid);
+        set_bit(NFS_OPEN_STATE, &state->flags);
         switch (fmode) {
                 case FMODE_READ:
                         set_bit(NFS_O_RDONLY_STATE, &state->flags);
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 1eb17285c99a..b7796950eceb 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1024,12 +1024,16 @@ out:
 
 static int nfs4_copy_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
 {
+        const nfs4_stateid *src;
         int ret;
         int seq;
 
         do {
+                src = &zero_stateid;
                 seq = read_seqbegin(&state->seqlock);
-                nfs4_stateid_copy(dst, &state->stateid);
+                if (test_bit(NFS_OPEN_STATE, &state->flags))
+                        src = &state->open_stateid;
+                nfs4_stateid_copy(dst, src);
                 ret = 0;
                 smp_rmb();
                 if (!list_empty(&state->owner->so_seqid.list))