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NFSv4: Use RCU to protect delegations

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Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-07-06 15:12:04 -04:00
parent 13437e12fb
commit 8383e4602c
2 changed files with 73 additions and 55 deletions
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106
fs/nfs/delegation.c
View file

@ -27,6 +27,13 @@ static void nfs_free_delegation(struct nfs_delegation *delegation)
kfree(delegation);
}
static void nfs_free_delegation_callback(struct rcu_head *head)
{
struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
nfs_free_delegation(delegation);
}
static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
{
struct inode *inode = state->inode;
@ -133,10 +140,10 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
delegation->inode = inode;
spin_lock(&clp->cl_lock);
if (nfsi->delegation == NULL) {
list_add(&delegation->super_list, &clp->cl_delegations);
nfsi->delegation = delegation;
if (rcu_dereference(nfsi->delegation) == NULL) {
list_add_rcu(&delegation->super_list, &clp->cl_delegations);
nfsi->delegation_state = delegation->type;
rcu_assign_pointer(nfsi->delegation, delegation);
delegation = NULL;
} else {
if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
@ -157,7 +164,7 @@ static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *
int res = 0;
res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
nfs_free_delegation(delegation);
call_rcu(&delegation->rcu, nfs_free_delegation_callback);
return res;
}
@ -191,16 +198,16 @@ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegat
static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
{
struct nfs_delegation *delegation = nfsi->delegation;
struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
if (delegation == NULL)
goto nomatch;
if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
sizeof(delegation->stateid.data)) != 0)
goto nomatch;
list_del_init(&delegation->super_list);
nfsi->delegation = NULL;
list_del_rcu(&delegation->super_list);
nfsi->delegation_state = 0;
rcu_assign_pointer(nfsi->delegation, NULL);
return delegation;
nomatch:
return NULL;
@ -213,7 +220,7 @@ int nfs_inode_return_delegation(struct inode *inode)
struct nfs_delegation *delegation;
int err = 0;
if (nfsi->delegation_state != 0) {
if (rcu_dereference(nfsi->delegation) != NULL) {
spin_lock(&clp->cl_lock);
delegation = nfs_detach_delegation_locked(nfsi, NULL);
spin_unlock(&clp->cl_lock);
@ -235,20 +242,23 @@ void nfs_return_all_delegations(struct super_block *sb)
if (clp == NULL)
return;
restart:
spin_lock(&clp->cl_lock);
list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
rcu_read_lock();
list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
if (delegation->inode->i_sb != sb)
continue;
inode = igrab(delegation->inode);
if (inode == NULL)
continue;
nfs_detach_delegation_locked(NFS_I(inode), NULL);
spin_lock(&clp->cl_lock);
delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
if (delegation != NULL)
__nfs_inode_return_delegation(inode, delegation);
iput(inode);
goto restart;
}
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
}
static int nfs_do_expire_all_delegations(void *ptr)
@ -259,23 +269,26 @@ static int nfs_do_expire_all_delegations(void *ptr)
allow_signal(SIGKILL);
restart:
spin_lock(&clp->cl_lock);
if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
goto out;
if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
goto out;
list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
rcu_read_lock();
list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
inode = igrab(delegation->inode);
if (inode == NULL)
continue;
nfs_detach_delegation_locked(NFS_I(inode), NULL);
spin_lock(&clp->cl_lock);
delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
if (delegation)
__nfs_inode_return_delegation(inode, delegation);
iput(inode);
goto restart;
}
rcu_read_unlock();
out:
spin_unlock(&clp->cl_lock);
nfs_put_client(clp);
module_put_and_exit(0);
}
@ -306,18 +319,21 @@ void nfs_handle_cb_pathdown(struct nfs_client *clp)
if (clp == NULL)
return;
restart:
spin_lock(&clp->cl_lock);
list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
rcu_read_lock();
list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
inode = igrab(delegation->inode);
if (inode == NULL)
continue;
nfs_detach_delegation_locked(NFS_I(inode), NULL);
spin_lock(&clp->cl_lock);
delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
if (delegation != NULL)
__nfs_inode_return_delegation(inode, delegation);
iput(inode);
goto restart;
}
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
}
struct recall_threadargs {
@ -391,14 +407,14 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs
{
struct nfs_delegation *delegation;
struct inode *res = NULL;
spin_lock(&clp->cl_lock);
list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
rcu_read_lock();
list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
res = igrab(delegation->inode);
break;
}
}
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
return res;
}
@ -408,10 +424,10 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs
void nfs_delegation_mark_reclaim(struct nfs_client *clp)
{
struct nfs_delegation *delegation;
spin_lock(&clp->cl_lock);
list_for_each_entry(delegation, &clp->cl_delegations, super_list)
rcu_read_lock();
list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
}
/*
@ -419,39 +435,35 @@ void nfs_delegation_mark_reclaim(struct nfs_client *clp)
*/
void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
{
struct nfs_delegation *delegation, *n;
LIST_HEAD(head);
spin_lock(&clp->cl_lock);
list_for_each_entry_safe(delegation, n, &clp->cl_delegations, super_list) {
struct nfs_delegation *delegation;
restart:
rcu_read_lock();
list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
continue;
list_move(&delegation->super_list, &head);
NFS_I(delegation->inode)->delegation = NULL;
NFS_I(delegation->inode)->delegation_state = 0;
}
spin_lock(&clp->cl_lock);
delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
spin_unlock(&clp->cl_lock);
while(!list_empty(&head)) {
delegation = list_entry(head.next, struct nfs_delegation, super_list);
list_del(&delegation->super_list);
nfs_free_delegation(delegation);
rcu_read_unlock();
if (delegation != NULL)
call_rcu(&delegation->rcu, nfs_free_delegation_callback);
goto restart;
}
rcu_read_unlock();
}
int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
{
struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_delegation *delegation;
int res = 0;
int ret = 0;
if (nfsi->delegation_state == 0)
return 0;
spin_lock(&clp->cl_lock);
delegation = nfsi->delegation;
rcu_read_lock();
delegation = rcu_dereference(nfsi->delegation);
if (delegation != NULL) {
memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
res = 1;
ret = 1;
}
spin_unlock(&clp->cl_lock);
return res;
rcu_read_unlock();
return ret;
}

14
fs/nfs/delegation.h
View file

@ -22,6 +22,7 @@ struct nfs_delegation {
long flags;
loff_t maxsize;
__u64 change_attr;
struct rcu_head rcu;
};
int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
@ -45,11 +46,16 @@ int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode);
static inline int nfs_have_delegation(struct inode *inode, int flags)
{
struct nfs_delegation *delegation;
int ret = 0;
flags &= FMODE_READ|FMODE_WRITE;
smp_rmb();
if ((NFS_I(inode)->delegation_state & flags) == flags)
return 1;
return 0;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (delegation != NULL && (delegation->type & flags) == flags)
ret = 1;
rcu_read_unlock();
return ret;
}
#else