NFSv4: Always use the delegation if we have one

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

3 files changed, 94 insertions, 36 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 44b56c915f72..4a1c4d80a577 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -122,7 +122,10 @@ struct nfs4_lock_state {
 /* bits for nfs4_state->flags */
 enum {
         LK_STATE_IN_USE,
-        NFS_DELEGATED_STATE,
+        NFS_DELEGATED_STATE,            /* Current stateid is delegation */
+        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 */
 };
 
 struct nfs4_state {
@@ -136,11 +139,12 @@ struct nfs4_state {
         unsigned long flags;            /* Do we hold any locks? */
         spinlock_t state_lock;          /* Protects the lock_states list */
 
-        nfs4_stateid stateid;
+        nfs4_stateid stateid;           /* Current stateid: may be delegation */
+        nfs4_stateid open_stateid;      /* OPEN stateid */
 
-        unsigned int n_rdonly;
-        unsigned int n_wronly;
-        unsigned int n_rdwr;
+        unsigned int n_rdonly;          /* Number of read-only references */
+        unsigned int n_wronly;          /* Number of write-only references */
+        unsigned int n_rdwr;            /* Number of read/write references */
         int state;                      /* State on the server (R,W, or RW) */
         atomic_t count;
 };
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 61ba32af4d2f..128fe23d3f1e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -319,7 +319,7 @@ static int nfs4_wait_for_completion_rpc_task(struct rpc_task *task)
         return ret;
 }
 
-static inline void update_open_stateflags(struct nfs4_state *state, mode_t open_flags)
+static void update_open_stateflags(struct nfs4_state *state, mode_t open_flags)
 {
         switch (open_flags) {
                 case FMODE_WRITE:
@@ -331,9 +331,36 @@ static inline void update_open_stateflags(struct nfs4_state *state, mode_t open_
                 case FMODE_READ|FMODE_WRITE:
                         state->n_rdwr++;
         }
+        nfs4_state_set_mode_locked(state, state->state | open_flags);
+}
+
+static void nfs_set_open_stateid_locked(struct nfs4_state *state, nfs4_stateid *stateid, int open_flags)
+{
+        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
+                memcpy(state->stateid.data, stateid->data, sizeof(state->stateid.data));
+        memcpy(state->open_stateid.data, stateid->data, sizeof(state->open_stateid.data));
+        switch (open_flags) {
+                case FMODE_READ:
+                        set_bit(NFS_O_RDONLY_STATE, &state->flags);
+                        break;
+                case FMODE_WRITE:
+                        set_bit(NFS_O_WRONLY_STATE, &state->flags);
+                        break;
+                case FMODE_READ|FMODE_WRITE:
+                        set_bit(NFS_O_RDWR_STATE, &state->flags);
+        }
 }
 
-static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, int open_flags)
+static void nfs_set_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, int open_flags)
+{
+        spin_lock(&state->owner->so_lock);
+        spin_lock(&state->inode->i_lock);
+        nfs_set_open_stateid_locked(state, stateid, open_flags);
+        spin_unlock(&state->inode->i_lock);
+        spin_unlock(&state->owner->so_lock);
+}
+
+static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stateid, nfs4_stateid *deleg_stateid, int open_flags)
 {
         struct inode *inode = state->inode;
 
@@ -341,9 +368,13 @@ static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid,
         /* Protect against nfs4_find_state_byowner() */
         spin_lock(&state->owner->so_lock);
         spin_lock(&inode->i_lock);
-        memcpy(&state->stateid, stateid, sizeof(state->stateid));
+        if (deleg_stateid != NULL) {
+                memcpy(state->stateid.data, deleg_stateid->data, sizeof(state->stateid.data));
+                set_bit(NFS_DELEGATED_STATE, &state->flags);
+        }
+        if (open_stateid != NULL)
+                nfs_set_open_stateid_locked(state, open_stateid, open_flags);
         update_open_stateflags(state, open_flags);
-        nfs4_state_set_mode_locked(state, state->state | open_flags);
         spin_unlock(&inode->i_lock);
         spin_unlock(&state->owner->so_lock);
 }
@@ -352,6 +383,8 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data
 {
         struct inode *inode;
         struct nfs4_state *state = NULL;
+        struct nfs_delegation *delegation;
+        nfs4_stateid *deleg_stateid = NULL;
 
         if (!(data->f_attr.valid & NFS_ATTR_FATTR))
                 goto out;
@@ -361,13 +394,14 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data
         state = nfs4_get_open_state(inode, data->owner);
         if (state == NULL)
                 goto put_inode;
-        update_open_stateid(state, &data->o_res.stateid, data->o_arg.open_flags);
         if (data->o_res.delegation_type != 0) {
-                struct nfs_inode *nfsi = NFS_I(inode);
                 int delegation_flags = 0;
 
-                if (nfsi->delegation)
-                        delegation_flags = nfsi->delegation->flags;
+                rcu_read_lock();
+                delegation = rcu_dereference(NFS_I(inode)->delegation);
+                if (delegation)
+                        delegation_flags = delegation->flags;
+                rcu_read_unlock();
                 if (!(delegation_flags & NFS_DELEGATION_NEED_RECLAIM))
                         nfs_inode_set_delegation(state->inode,
                                         data->owner->so_cred,
@@ -377,6 +411,12 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data
                                         data->owner->so_cred,
                                         &data->o_res);
         }
+        rcu_read_lock();
+        delegation = rcu_dereference(NFS_I(inode)->delegation);
+        if (delegation != NULL)
+                deleg_stateid = &delegation->stateid;
+        update_open_stateid(state, &data->o_res.stateid, deleg_stateid, data->o_arg.open_flags);
+        rcu_read_unlock();
 put_inode:
         iput(inode);
 out:
@@ -911,8 +951,7 @@ static int _nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred
         unlock_kernel();
         if (err != 0)
                 goto out_put_open_state;
-        set_bit(NFS_DELEGATED_STATE, &state->flags);
-        update_open_stateid(state, &delegation->stateid, open_flags);
+        update_open_stateid(state, NULL, &delegation->stateid, open_flags);
 out_ok:
         nfs4_put_state_owner(sp);
         up_read(&nfsi->rwsem);
@@ -1149,8 +1188,7 @@ static void nfs4_close_done(struct rpc_task *task, void *data)
         nfs_increment_open_seqid(task->tk_status, calldata->arg.seqid);
         switch (task->tk_status) {
                 case 0:
-                        memcpy(&state->stateid, &calldata->res.stateid,
-                                        sizeof(state->stateid));
+                        nfs_set_open_stateid(state, &calldata->res.stateid, calldata->arg.open_flags);
                         renew_lease(server, calldata->timestamp);
                         break;
                 case -NFS4ERR_STALE_STATEID:
@@ -1175,26 +1213,32 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
                 .rpc_resp = &calldata->res,
                 .rpc_cred = state->owner->so_cred,
         };
-        int mode = 0, old_mode;
+        int clear_rd, clear_wr, clear_rdwr;
+        int mode;
 
         if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
                 return;
-        /* Recalculate the new open mode in case someone reopened the file
-         * while we were waiting in line to be scheduled.
-         */
+
+        mode = FMODE_READ|FMODE_WRITE;
+        clear_rd = clear_wr = clear_rdwr = 0;
         spin_lock(&state->owner->so_lock);
         spin_lock(&calldata->inode->i_lock);
-        mode = old_mode = state->state;
+        /* Calculate the change in open mode */
         if (state->n_rdwr == 0) {
-                if (state->n_rdonly == 0)
+                if (state->n_rdonly == 0) {
                         mode &= ~FMODE_READ;
-                if (state->n_wronly == 0)
+                        clear_rd |= test_and_clear_bit(NFS_O_RDONLY_STATE, &state->flags);
+                        clear_rdwr |= test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags);
+                }
+                if (state->n_wronly == 0) {
                         mode &= ~FMODE_WRITE;
+                        clear_wr |= test_and_clear_bit(NFS_O_WRONLY_STATE, &state->flags);
+                        clear_rdwr |= test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags);
+                }
         }
-        nfs4_state_set_mode_locked(state, mode);
         spin_unlock(&calldata->inode->i_lock);
         spin_unlock(&state->owner->so_lock);
-        if (mode == old_mode || test_bit(NFS_DELEGATED_STATE, &state->flags)) {
+        if (!clear_rd && !clear_wr && !clear_rdwr) {
                 /* Note: exit _without_ calling nfs4_close_done */
                 task->tk_action = NULL;
                 return;
@@ -1238,7 +1282,7 @@ int nfs4_do_close(struct path *path, struct nfs4_state *state)
         calldata->inode = state->inode;
         calldata->state = state;
         calldata->arg.fh = NFS_FH(state->inode);
-        calldata->arg.stateid = &state->stateid;
+        calldata->arg.stateid = &state->open_stateid;
         /* Serialization for the sequence id */
         calldata->arg.seqid = nfs_alloc_seqid(&state->owner->so_seqid);
         if (calldata->arg.seqid == NULL)
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index ac816b303f3a..4f78c0d1eab5 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -412,7 +412,8 @@ void nfs4_close_state(struct path *path, struct nfs4_state *state, mode_t mode)
 {
         struct inode *inode = state->inode;
         struct nfs4_state_owner *owner = state->owner;
-        int oldstate, newstate = 0;
+        int call_close = 0;
+        int newstate;
 
         atomic_inc(&owner->so_count);
         /* Protect against nfs4_find_state() */
@@ -428,21 +429,26 @@ void nfs4_close_state(struct path *path, struct nfs4_state *state, mode_t mode)
                 case FMODE_READ|FMODE_WRITE:
                         state->n_rdwr--;
         }
-        oldstate = newstate = state->state;
+        newstate = FMODE_READ|FMODE_WRITE;
         if (state->n_rdwr == 0) {
-                if (state->n_rdonly == 0)
+                if (state->n_rdonly == 0) {
                         newstate &= ~FMODE_READ;
-                if (state->n_wronly == 0)
+                        call_close |= test_bit(NFS_O_RDONLY_STATE, &state->flags);
+                        call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
+                }
+                if (state->n_wronly == 0) {
                         newstate &= ~FMODE_WRITE;
+                        call_close |= test_bit(NFS_O_WRONLY_STATE, &state->flags);
+                        call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
+                }
+                if (newstate == 0)
+                        clear_bit(NFS_DELEGATED_STATE, &state->flags);
         }
-        if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
-                nfs4_state_set_mode_locked(state, newstate);
-                oldstate = newstate;
-        }
+        nfs4_state_set_mode_locked(state, newstate);
         spin_unlock(&inode->i_lock);
         spin_unlock(&owner->so_lock);
 
-        if (oldstate == newstate) {
+        if (!call_close) {
                 nfs4_put_open_state(state);
                 nfs4_put_state_owner(owner);
         } else
@@ -838,6 +844,10 @@ static void nfs4_state_mark_reclaim(struct nfs_client *clp)
                 sp->so_seqid.flags = 0;
                 spin_lock(&sp->so_lock);
                 list_for_each_entry(state, &sp->so_states, open_states) {
+                        clear_bit(NFS_DELEGATED_STATE, &state->flags);
+                        clear_bit(NFS_O_RDONLY_STATE, &state->flags);
+                        clear_bit(NFS_O_WRONLY_STATE, &state->flags);
+                        clear_bit(NFS_O_RDWR_STATE, &state->flags);
                         list_for_each_entry(lock, &state->lock_states, ls_locks) {
                                 lock->ls_seqid.counter = 0;
                                 lock->ls_seqid.flags = 0;