Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Fix RCU issues in the NFSv4 delegation code
NFSv4: Fix the locking in nfs_inode_reclaim_delegation()
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 1567124..ea61d26 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -24,6 +24,8 @@
static void nfs_do_free_delegation(struct nfs_delegation *delegation)
{
+ if (delegation->cred)
+ put_rpccred(delegation->cred);
kfree(delegation);
}
@@ -36,13 +38,7 @@
static void nfs_free_delegation(struct nfs_delegation *delegation)
{
- struct rpc_cred *cred;
-
- cred = rcu_dereference(delegation->cred);
- rcu_assign_pointer(delegation->cred, NULL);
call_rcu(&delegation->rcu, nfs_free_delegation_callback);
- if (cred)
- put_rpccred(cred);
}
void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
@@ -129,21 +125,35 @@
*/
void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
{
- struct nfs_delegation *delegation = NFS_I(inode)->delegation;
- struct rpc_cred *oldcred;
+ struct nfs_delegation *delegation;
+ struct rpc_cred *oldcred = NULL;
- if (delegation == NULL)
- return;
- memcpy(delegation->stateid.data, res->delegation.data,
- sizeof(delegation->stateid.data));
- delegation->type = res->delegation_type;
- delegation->maxsize = res->maxsize;
- oldcred = delegation->cred;
- delegation->cred = get_rpccred(cred);
- clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
- NFS_I(inode)->delegation_state = delegation->type;
- smp_wmb();
- put_rpccred(oldcred);
+ rcu_read_lock();
+ delegation = rcu_dereference(NFS_I(inode)->delegation);
+ if (delegation != NULL) {
+ spin_lock(&delegation->lock);
+ if (delegation->inode != NULL) {
+ memcpy(delegation->stateid.data, res->delegation.data,
+ sizeof(delegation->stateid.data));
+ delegation->type = res->delegation_type;
+ delegation->maxsize = res->maxsize;
+ oldcred = delegation->cred;
+ delegation->cred = get_rpccred(cred);
+ clear_bit(NFS_DELEGATION_NEED_RECLAIM,
+ &delegation->flags);
+ NFS_I(inode)->delegation_state = delegation->type;
+ spin_unlock(&delegation->lock);
+ put_rpccred(oldcred);
+ rcu_read_unlock();
+ } else {
+ /* We appear to have raced with a delegation return. */
+ spin_unlock(&delegation->lock);
+ rcu_read_unlock();
+ nfs_inode_set_delegation(inode, cred, res);
+ }
+ } else {
+ rcu_read_unlock();
+ }
}
static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
@@ -166,9 +176,13 @@
return inode;
}
-static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
+static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi,
+ const nfs4_stateid *stateid,
+ struct nfs_client *clp)
{
- struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
+ struct nfs_delegation *delegation =
+ rcu_dereference_protected(nfsi->delegation,
+ lockdep_is_held(&clp->cl_lock));
if (delegation == NULL)
goto nomatch;
@@ -195,7 +209,7 @@
{
struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
struct nfs_inode *nfsi = NFS_I(inode);
- struct nfs_delegation *delegation;
+ struct nfs_delegation *delegation, *old_delegation;
struct nfs_delegation *freeme = NULL;
int status = 0;
@@ -213,10 +227,12 @@
spin_lock_init(&delegation->lock);
spin_lock(&clp->cl_lock);
- if (rcu_dereference(nfsi->delegation) != NULL) {
- if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
- sizeof(delegation->stateid)) == 0 &&
- delegation->type == nfsi->delegation->type) {
+ old_delegation = rcu_dereference_protected(nfsi->delegation,
+ lockdep_is_held(&clp->cl_lock));
+ if (old_delegation != NULL) {
+ if (memcmp(&delegation->stateid, &old_delegation->stateid,
+ sizeof(old_delegation->stateid)) == 0 &&
+ delegation->type == old_delegation->type) {
goto out;
}
/*
@@ -226,12 +242,12 @@
dfprintk(FILE, "%s: server %s handed out "
"a duplicate delegation!\n",
__func__, clp->cl_hostname);
- if (delegation->type <= nfsi->delegation->type) {
+ if (delegation->type <= old_delegation->type) {
freeme = delegation;
delegation = NULL;
goto out;
}
- freeme = nfs_detach_delegation_locked(nfsi, NULL);
+ freeme = nfs_detach_delegation_locked(nfsi, NULL, clp);
}
list_add_rcu(&delegation->super_list, &clp->cl_delegations);
nfsi->delegation_state = delegation->type;
@@ -301,7 +317,7 @@
if (inode == NULL)
continue;
spin_lock(&clp->cl_lock);
- delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
+ delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
if (delegation != NULL) {
@@ -330,9 +346,9 @@
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_delegation *delegation;
- if (rcu_dereference(nfsi->delegation) != NULL) {
+ if (rcu_access_pointer(nfsi->delegation) != NULL) {
spin_lock(&clp->cl_lock);
- delegation = nfs_detach_delegation_locked(nfsi, NULL);
+ delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
spin_unlock(&clp->cl_lock);
if (delegation != NULL)
nfs_do_return_delegation(inode, delegation, 0);
@@ -346,9 +362,9 @@
struct nfs_delegation *delegation;
int err = 0;
- if (rcu_dereference(nfsi->delegation) != NULL) {
+ if (rcu_access_pointer(nfsi->delegation) != NULL) {
spin_lock(&clp->cl_lock);
- delegation = nfs_detach_delegation_locked(nfsi, NULL);
+ delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
spin_unlock(&clp->cl_lock);
if (delegation != NULL) {
nfs_msync_inode(inode);
@@ -526,7 +542,7 @@
if (inode == NULL)
continue;
spin_lock(&clp->cl_lock);
- delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
+ delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
spin_unlock(&clp->cl_lock);
rcu_read_unlock();
if (delegation != NULL)