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NFSv4: nfs4_copy_delegation_stateid() must fail if the delegation is invalid

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We must not allow the use of delegations that have been revoked or are
being returned.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Fixes: 869f9dfa4d ("NFSv4: Fix races between nfs_remove_bad_delegation()...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v3.19+
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Trond Myklebust 2016-09-22 13:38:54 -04:00 committed by Anna Schumaker
parent b3f9e72390
commit aa05c87f23
1 changed files with 13 additions and 4 deletions
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17
fs/nfs/delegation.c
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@ -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);