NFSv4: Fix a race between open() and close()
We must not remove the nfs4_state structure from the inode open lists
before we are in sequence lock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 78a53f5..5396902 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -214,7 +214,7 @@
extern int nfs4_proc_setclientid_confirm(struct nfs4_client *);
extern int nfs4_proc_async_renew(struct nfs4_client *);
extern int nfs4_proc_renew(struct nfs4_client *);
-extern int nfs4_do_close(struct inode *inode, struct nfs4_state *state, mode_t mode);
+extern int nfs4_do_close(struct inode *inode, struct nfs4_state *state);
extern struct dentry *nfs4_atomic_open(struct inode *, struct dentry *, struct nameidata *);
extern int nfs4_open_revalidate(struct inode *, struct dentry *, int, struct nameidata *);
@@ -248,6 +248,7 @@
extern void nfs4_put_open_state(struct nfs4_state *);
extern void nfs4_close_state(struct nfs4_state *, mode_t);
extern struct nfs4_state *nfs4_find_state(struct inode *, struct rpc_cred *, mode_t mode);
+extern void nfs4_state_set_mode_locked(struct nfs4_state *, mode_t);
extern void nfs4_schedule_state_recovery(struct nfs4_client *);
extern void nfs4_put_lock_state(struct nfs4_lock_state *lsp);
extern int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 933e13b..02fddd0 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -217,13 +217,12 @@
/* Protect against nfs4_find_state() */
spin_lock(&state->owner->so_lock);
spin_lock(&inode->i_lock);
- state->state |= open_flags;
- /* NB! List reordering - see the reclaim code for why. */
- if ((open_flags & FMODE_WRITE) && 0 == state->nwriters++)
- list_move(&state->open_states, &state->owner->so_states);
+ memcpy(&state->stateid, stateid, sizeof(state->stateid));
+ if ((open_flags & FMODE_WRITE))
+ state->nwriters++;
if (open_flags & FMODE_READ)
state->nreaders++;
- memcpy(&state->stateid, stateid, sizeof(state->stateid));
+ nfs4_state_set_mode_locked(state, state->state | open_flags);
spin_unlock(&inode->i_lock);
spin_unlock(&state->owner->so_lock);
}
@@ -896,7 +895,6 @@
break;
case -NFS4ERR_STALE_STATEID:
case -NFS4ERR_EXPIRED:
- state->state = calldata->arg.open_flags;
nfs4_schedule_state_recovery(server->nfs4_state);
break;
default:
@@ -906,7 +904,6 @@
}
}
nfs_refresh_inode(calldata->inode, calldata->res.fattr);
- state->state = calldata->arg.open_flags;
nfs4_free_closedata(calldata);
}
@@ -920,24 +917,26 @@
.rpc_resp = &calldata->res,
.rpc_cred = state->owner->so_cred,
};
- int mode = 0;
+ int mode = 0, old_mode;
int status;
status = nfs_wait_on_sequence(calldata->arg.seqid, task);
if (status != 0)
return;
- /* Don't reorder reads */
- smp_rmb();
/* Recalculate the new open mode in case someone reopened the file
* while we were waiting in line to be scheduled.
*/
- if (state->nreaders != 0)
- mode |= FMODE_READ;
- if (state->nwriters != 0)
- mode |= FMODE_WRITE;
- if (test_bit(NFS_DELEGATED_STATE, &state->flags))
- state->state = mode;
- if (mode == state->state) {
+ 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;
+ 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)) {
nfs4_free_closedata(calldata);
task->tk_exit = NULL;
rpc_exit(task, 0);
@@ -961,7 +960,7 @@
*
* NOTE: Caller must be holding the sp->so_owner semaphore!
*/
-int nfs4_do_close(struct inode *inode, struct nfs4_state *state, mode_t mode)
+int nfs4_do_close(struct inode *inode, struct nfs4_state *state)
{
struct nfs_server *server = NFS_SERVER(inode);
struct nfs4_closedata *calldata;
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 2d5a6a2..959374d 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -366,6 +366,23 @@
return state;
}
+void
+nfs4_state_set_mode_locked(struct nfs4_state *state, mode_t mode)
+{
+ if (state->state == mode)
+ return;
+ /* NB! List reordering - see the reclaim code for why. */
+ if ((mode & FMODE_WRITE) != (state->state & FMODE_WRITE)) {
+ if (mode & FMODE_WRITE)
+ list_move(&state->open_states, &state->owner->so_states);
+ else
+ list_move_tail(&state->open_states, &state->owner->so_states);
+ }
+ if (mode == 0)
+ list_del_init(&state->inode_states);
+ state->state = mode;
+}
+
static struct nfs4_state *
__nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode)
{
@@ -376,10 +393,6 @@
list_for_each_entry(state, &nfsi->open_states, inode_states) {
if (state->owner->so_cred != cred)
continue;
- if ((mode & FMODE_READ) != 0 && state->nreaders == 0)
- continue;
- if ((mode & FMODE_WRITE) != 0 && state->nwriters == 0)
- continue;
if ((state->state & mode) != mode)
continue;
atomic_inc(&state->count);
@@ -400,7 +413,7 @@
list_for_each_entry(state, &nfsi->open_states, inode_states) {
/* Is this in the process of being freed? */
- if (state->nreaders == 0 && state->nwriters == 0)
+ if (state->state == 0)
continue;
if (state->owner == owner) {
atomic_inc(&state->count);
@@ -481,7 +494,6 @@
spin_unlock(&inode->i_lock);
spin_unlock(&owner->so_lock);
iput(inode);
- BUG_ON (state->state != 0);
nfs4_free_open_state(state);
nfs4_put_state_owner(owner);
}
@@ -493,7 +505,7 @@
{
struct inode *inode = state->inode;
struct nfs4_state_owner *owner = state->owner;
- int newstate;
+ int oldstate, newstate = 0;
atomic_inc(&owner->so_count);
/* Protect against nfs4_find_state() */
@@ -503,30 +515,20 @@
state->nreaders--;
if (mode & FMODE_WRITE)
state->nwriters--;
- if (state->nwriters == 0) {
- if (state->nreaders == 0)
- list_del_init(&state->inode_states);
- /* See reclaim code */
- list_move_tail(&state->open_states, &owner->so_states);
+ oldstate = newstate = state->state;
+ if (state->nreaders == 0)
+ newstate &= ~FMODE_READ;
+ if (state->nwriters == 0)
+ newstate &= ~FMODE_WRITE;
+ if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
+ nfs4_state_set_mode_locked(state, newstate);
+ oldstate = newstate;
}
spin_unlock(&inode->i_lock);
spin_unlock(&owner->so_lock);
- newstate = 0;
- if (state->state != 0) {
- if (state->nreaders)
- newstate |= FMODE_READ;
- if (state->nwriters)
- newstate |= FMODE_WRITE;
- if (state->state == newstate)
- goto out;
- if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
- state->state = newstate;
- goto out;
- }
- if (nfs4_do_close(inode, state, newstate) == 0)
- return;
- }
-out:
+
+ if (oldstate != newstate && nfs4_do_close(inode, state) == 0)
+ return;
nfs4_put_open_state(state);
nfs4_put_state_owner(owner);
}
