We must not allow the use of delegations that have been revoked or are
being returned.
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Fixes: 869f9dfa4d6d ("NFSv4: Fix races between nfs_remove_bad_delegation()...")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v3.19+
---
fs/nfs/delegation.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 86d2c748140b..b9c65421ed81 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -41,6 +41,17 @@ void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
}
+static bool
+nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
+ fmode_t flags)
+{
+ if (delegation != NULL && (delegation->type & flags) == flags &&
+ !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
+ !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
+ return true;
+ return false;
+}
+
static int
nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
{
@@ -50,9 +61,7 @@ nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
flags &= FMODE_READ|FMODE_WRITE;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(inode)->delegation);
- if (delegation != NULL && (delegation->type & flags) == flags &&
- !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
- !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
+ if (nfs4_is_valid_delegation(delegation, flags)) {
if (mark)
nfs_mark_delegation_referenced(delegation);
ret = 1;
@@ -894,7 +903,7 @@ bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
flags &= FMODE_READ|FMODE_WRITE;
rcu_read_lock();
delegation = rcu_dereference(nfsi->delegation);
- ret = (delegation != NULL && (delegation->type & flags) == flags);
+ ret = nfs4_is_valid_delegation(delegation, flags);
if (ret) {
nfs4_stateid_copy(dst, &delegation->stateid);
nfs_mark_delegation_referenced(delegation);
--
2.7.4
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