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Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/n…
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…fs-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()
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@torvalds
torvalds committed May 7, 2010
2 parents 4a22533 + 17d2c0a commit 9167746
Showing 1 changed file with 51 additions and 35 deletions.
86 changes: 51 additions & 35 deletions fs/nfs/delegation.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,8 @@

static void nfs_do_free_delegation(struct nfs_delegation *delegation)
{
if (delegation->cred)
put_rpccred(delegation->cred);
kfree(delegation);
}

Expand All @@ -36,13 +38,7 @@ static void nfs_free_delegation_callback(struct rcu_head *head)

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)
Expand Down Expand Up @@ -129,21 +125,35 @@ static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *s
*/
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)
Expand All @@ -166,9 +176,13 @@ static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation
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;
Expand All @@ -195,7 +209,7 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
{
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;

Expand All @@ -213,10 +227,12 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
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;
}
/*
Expand All @@ -226,12 +242,12 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
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;
Expand Down Expand Up @@ -301,7 +317,7 @@ int nfs_client_return_marked_delegations(struct nfs_client *clp)
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) {
Expand Down Expand Up @@ -330,9 +346,9 @@ void nfs_inode_return_delegation_noreclaim(struct inode *inode)
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);
Expand All @@ -346,9 +362,9 @@ int nfs_inode_return_delegation(struct inode *inode)
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);
Expand Down Expand Up @@ -526,7 +542,7 @@ void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
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)
Expand Down

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