NFSv4: Deal more correctly with duplicate delegations
If a (broken?) server hands out two different delegations for the same
file, then we should return one of them.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 2dead8d..b9eadd1 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -125,6 +125,32 @@
put_rpccred(oldcred);
}
+static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
+{
+ int res = 0;
+
+ res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
+ nfs_free_delegation(delegation);
+ return res;
+}
+
+static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
+{
+ 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_rcu(&delegation->super_list);
+ nfsi->delegation_state = 0;
+ rcu_assign_pointer(nfsi->delegation, NULL);
+ return delegation;
+nomatch:
+ return NULL;
+}
+
/*
* Set up a delegation on an inode
*/
@@ -133,6 +159,7 @@
struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_delegation *delegation;
+ struct nfs_delegation *freeme = NULL;
int status = 0;
delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
@@ -147,42 +174,45 @@
delegation->inode = inode;
spin_lock(&clp->cl_lock);
- 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 (rcu_dereference(nfsi->delegation) != NULL) {
if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
- sizeof(delegation->stateid)) != 0 ||
- delegation->type != nfsi->delegation->type) {
- printk(KERN_WARNING "%s: server %s handed out "
- "a duplicate delegation!\n",
- __FUNCTION__, clp->cl_hostname);
- status = -EIO;
+ sizeof(delegation->stateid)) == 0 &&
+ delegation->type == nfsi->delegation->type) {
+ goto out;
}
+ /*
+ * Deal with broken servers that hand out two
+ * delegations for the same file.
+ */
+ dfprintk(FILE, "%s: server %s handed out "
+ "a duplicate delegation!\n",
+ __FUNCTION__, clp->cl_hostname);
+ if (delegation->type <= nfsi->delegation->type) {
+ freeme = delegation;
+ delegation = NULL;
+ goto out;
+ }
+ freeme = nfs_detach_delegation_locked(nfsi, NULL);
}
+ list_add_rcu(&delegation->super_list, &clp->cl_delegations);
+ nfsi->delegation_state = delegation->type;
+ rcu_assign_pointer(nfsi->delegation, delegation);
+ delegation = NULL;
/* Ensure we revalidate the attributes and page cache! */
spin_lock(&inode->i_lock);
nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
spin_unlock(&inode->i_lock);
+out:
spin_unlock(&clp->cl_lock);
if (delegation != NULL)
nfs_free_delegation(delegation);
+ if (freeme != NULL)
+ nfs_do_return_delegation(inode, freeme, 0);
return status;
}
-static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
-{
- int res = 0;
-
- res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
- nfs_free_delegation(delegation);
- return res;
-}
-
/* Sync all data to disk upon delegation return */
static void nfs_msync_inode(struct inode *inode)
{
@@ -211,23 +241,6 @@
return nfs_do_return_delegation(inode, delegation, 1);
}
-static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
-{
- 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_rcu(&delegation->super_list);
- nfsi->delegation_state = 0;
- rcu_assign_pointer(nfsi->delegation, NULL);
- return delegation;
-nomatch:
- return NULL;
-}
-
/*
* This function returns the delegation without reclaiming opens
* or protecting against delegation reclaims.
