NFSv4: Fix up stateid locking...
We really don't need to grab both the state->so_owner and the
inode->i_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 4a1c4d8..dd1aa2b 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -139,9 +139,11 @@
unsigned long flags; /* Do we hold any locks? */
spinlock_t state_lock; /* Protects the lock_states list */
+ seqlock_t seqlock; /* Protects the stateid/open_stateid */
nfs4_stateid stateid; /* Current stateid: may be delegation */
nfs4_stateid open_stateid; /* OPEN stateid */
+ /* The following 3 fields are protected by owner->so_lock */
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 */
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3a2af80..ba86ec6 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -385,29 +385,28 @@
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);
+ write_seqlock(&state->seqlock);
nfs_set_open_stateid_locked(state, stateid, open_flags);
- spin_unlock(&state->inode->i_lock);
- spin_unlock(&state->owner->so_lock);
+ write_sequnlock(&state->seqlock);
}
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;
-
open_flags &= (FMODE_READ|FMODE_WRITE);
- /* Protect against nfs4_find_state_byowner() */
- spin_lock(&state->owner->so_lock);
- spin_lock(&inode->i_lock);
+ /*
+ * Protect the call to nfs4_state_set_mode_locked and
+ * serialise the stateid update
+ */
+ write_seqlock(&state->seqlock);
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);
+ write_sequnlock(&state->seqlock);
+ spin_lock(&state->owner->so_lock);
update_open_stateflags(state, open_flags);
- spin_unlock(&inode->i_lock);
spin_unlock(&state->owner->so_lock);
}
@@ -608,12 +607,10 @@
*/
if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0 &&
memcmp(state->stateid.data, state->open_stateid.data, sizeof(state->stateid.data)) != 0) {
- spin_lock(&state->owner->so_lock);
- spin_lock(&state->inode->i_lock);
+ write_seqlock(&state->seqlock);
if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
memcpy(state->stateid.data, state->open_stateid.data, sizeof(state->stateid.data));
- spin_unlock(&state->inode->i_lock);
- spin_unlock(&state->owner->so_lock);
+ write_sequnlock(&state->seqlock);
}
return 0;
}
@@ -1280,7 +1277,6 @@
mode = FMODE_READ|FMODE_WRITE;
clear_rd = clear_wr = clear_rdwr = 0;
spin_lock(&state->owner->so_lock);
- spin_lock(&calldata->inode->i_lock);
/* Calculate the change in open mode */
if (state->n_rdwr == 0) {
if (state->n_rdonly == 0) {
@@ -1294,7 +1290,6 @@
clear_rdwr |= test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags);
}
}
- spin_unlock(&calldata->inode->i_lock);
spin_unlock(&state->owner->so_lock);
if (!clear_rd && !clear_wr && !clear_rdwr) {
/* Note: exit _without_ calling nfs4_close_done */
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 4fa4054..523cc2c 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -307,6 +307,7 @@
atomic_set(&state->count, 1);
INIT_LIST_HEAD(&state->lock_states);
spin_lock_init(&state->state_lock);
+ seqlock_init(&state->seqlock);
return state;
}
@@ -411,7 +412,6 @@
*/
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 call_close = 0;
int newstate;
@@ -419,7 +419,6 @@
atomic_inc(&owner->so_count);
/* Protect against nfs4_find_state() */
spin_lock(&owner->so_lock);
- spin_lock(&inode->i_lock);
switch (mode & (FMODE_READ | FMODE_WRITE)) {
case FMODE_READ:
state->n_rdonly--;
@@ -446,7 +445,6 @@
clear_bit(NFS_DELEGATED_STATE, &state->flags);
}
nfs4_state_set_mode_locked(state, newstate);
- spin_unlock(&inode->i_lock);
spin_unlock(&owner->so_lock);
if (!call_close) {
@@ -599,8 +597,12 @@
void nfs4_copy_stateid(nfs4_stateid *dst, struct nfs4_state *state, fl_owner_t fl_owner)
{
struct nfs4_lock_state *lsp;
+ int seq;
- memcpy(dst, &state->stateid, sizeof(*dst));
+ do {
+ seq = read_seqbegin(&state->seqlock);
+ memcpy(dst, &state->stateid, sizeof(*dst));
+ } while (read_seqretry(&state->seqlock, seq));
if (test_bit(LK_STATE_IN_USE, &state->flags) == 0)
return;