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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>
This commit is contained in:
Trond Myklebust 2005-11-04 15:32:58 -05:00
parent 462aae65f6
commit 4cecb76ff8
3 changed files with 49 additions and 47 deletions
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3
fs/nfs/nfs4_fs.h
View File

@ -214,7 +214,7 @@ extern int nfs4_proc_setclientid(struct nfs4_client *, u32, unsigned short);
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 struct nfs4_state * nfs4_get_open_state(struct inode *, struct nfs4_state
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);

35
fs/nfs/nfs4proc.c
View File

@ -217,13 +217,12 @@ static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid,
/* 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 @@ static void nfs4_close_done(struct rpc_task *task)
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 @@ static void nfs4_close_done(struct rpc_task *task)
}
}
nfs_refresh_inode(calldata->inode, calldata->res.fattr);
state->state = calldata->arg.open_flags;
nfs4_free_closedata(calldata);
}
@ -920,24 +917,26 @@ static void nfs4_close_begin(struct rpc_task *task)
.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 @@ static void nfs4_close_begin(struct rpc_task *task)
*
* 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;

58
fs/nfs/nfs4state.c
View File

@ -366,6 +366,23 @@ nfs4_alloc_open_state(void)
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 @@ __nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode)
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 @@ __nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner)
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 @@ void nfs4_put_open_state(struct nfs4_state *state)
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 @@ void nfs4_close_state(struct nfs4_state *state, mode_t mode)
{
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 @@ void nfs4_close_state(struct nfs4_state *state, mode_t mode)
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);
}