NFSv4: Make nfs4_state track O_RDWR, O_RDONLY and O_WRONLY separately

 A closer reading of RFC3530 reveals that OPEN_DOWNGRADE must always
 specify a access modes that have been the argument of a previous OPEN
 operation.
 IOW: doing OPEN(O_RDWR) and then OPEN_DOWNGRADE(O_WRONLY) is forbidden
 unless the user called OPEN(O_WRONLY)

 In order to fix that, we really need to track the three possible open
 states separately.

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

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index b7f262d..4ad5981 100644 (file)
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -182,8 +182,9 @@ struct nfs4_state {
 
        nfs4_stateid stateid;
 
-       unsigned int nreaders;
-       unsigned int nwriters;
+       unsigned int n_rdonly;
+       unsigned int n_wronly;
+       unsigned int n_rdwr;
        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 8154f25..e494cc2 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -297,6 +297,20 @@ 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)
+{
+       switch (open_flags) {
+               case FMODE_WRITE:
+                       state->n_wronly++;
+                       break;
+               case FMODE_READ:
+                       state->n_rdonly++;
+                       break;
+               case FMODE_READ|FMODE_WRITE:
+                       state->n_rdwr++;
+       }
+}
+
 static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, int open_flags)
 {
        struct inode *inode = state->inode;
@@ -306,10 +320,7 @@ static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid,
        spin_lock(&state->owner->so_lock);
        spin_lock(&inode->i_lock);
        memcpy(&state->stateid, stateid, sizeof(state->stateid));
-       if ((open_flags & FMODE_WRITE))
-               state->nwriters++;
-       if (open_flags & FMODE_READ)
-               state->nreaders++;
+       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);
@@ -822,10 +833,7 @@ static int _nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred
        err = -ENOENT;
        if ((state->state & open_flags) == open_flags) {
                spin_lock(&inode->i_lock);
-               if (open_flags & FMODE_READ)
-                       state->nreaders++;
-               if (open_flags & FMODE_WRITE)
-                       state->nwriters++;
+               update_open_stateflags(state, open_flags);
                spin_unlock(&inode->i_lock);
                goto out_ok;
        } else if (state->state != 0)
@@ -1082,10 +1090,12 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
        spin_lock(&state->owner->so_lock);
        spin_lock(&calldata->inode->i_lock);
        mode = old_mode = state->state;
-       if (state->nreaders == 0)
-               mode &= ~FMODE_READ;
-       if (state->nwriters == 0)
-               mode &= ~FMODE_WRITE;
+       if (state->n_rdwr == 0) {
+               if (state->n_rdonly == 0)
+                       mode &= ~FMODE_READ;
+               if (state->n_wronly == 0)
+                       mode &= ~FMODE_WRITE;
+       }
        nfs4_state_set_mode_locked(state, mode);
        spin_unlock(&calldata->inode->i_lock);
        spin_unlock(&state->owner->so_lock);

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 5ef4c57..41a5f1a 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -349,14 +349,9 @@ nfs4_alloc_open_state(void)
 {
        struct nfs4_state *state;
 
-       state = kmalloc(sizeof(*state), GFP_KERNEL);
+       state = kzalloc(sizeof(*state), GFP_KERNEL);
        if (!state)
                return NULL;
-       state->state = 0;
-       state->nreaders = 0;
-       state->nwriters = 0;
-       state->flags = 0;
-       memset(state->stateid.data, 0, sizeof(state->stateid.data));
        atomic_set(&state->count, 1);
        INIT_LIST_HEAD(&state->lock_states);
        spin_lock_init(&state->state_lock);
@@ -475,15 +470,23 @@ void nfs4_close_state(struct nfs4_state *state, mode_t mode)
        /* Protect against nfs4_find_state() */
        spin_lock(&owner->so_lock);
        spin_lock(&inode->i_lock);
-       if (mode & FMODE_READ)
-               state->nreaders--;
-       if (mode & FMODE_WRITE)
-               state->nwriters--;
+       switch (mode & (FMODE_READ | FMODE_WRITE)) {
+               case FMODE_READ:
+                       state->n_rdonly--;
+                       break;
+               case FMODE_WRITE:
+                       state->n_wronly--;
+                       break;
+               case FMODE_READ|FMODE_WRITE:
+                       state->n_rdwr--;
+       }
        oldstate = newstate = state->state;
-       if (state->nreaders == 0)
-               newstate &= ~FMODE_READ;
-       if (state->nwriters == 0)
-               newstate &= ~FMODE_WRITE;
+       if (state->n_rdwr == 0) {
+               if (state->n_rdonly == 0)
+                       newstate &= ~FMODE_READ;
+               if (state->n_wronly == 0)
+                       newstate &= ~FMODE_WRITE;
+       }
        if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
                nfs4_state_set_mode_locked(state, newstate);
                oldstate = newstate;