Commit aa05c87f authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
Browse files

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



We must not allow the use of delegations that have been revoked or are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

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Fixes: 869f9dfa ("NFSv4: Fix races between nfs_remove_bad_delegation()...")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v3.19+
Tested-by: default avatarOleg Drokin <green@linuxhacker.ru>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent b3f9e723

fs/nfs/delegation.c

+13 −4
Original line number Original line Diff line number Diff line
@@ -41,6 +41,17 @@ void nfs_mark_delegation_referenced(struct nfs_delegation *delegation) 
	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);

	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

static int

nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)

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;

	flags &= FMODE_READ|FMODE_WRITE;

	rcu_read_lock();

	rcu_read_lock();

	delegation = rcu_dereference(NFS_I(inode)->delegation);

	delegation = rcu_dereference(NFS_I(inode)->delegation);

	if (delegation != NULL && (delegation->type & flags) == flags &&

	if (nfs4_is_valid_delegation(delegation, flags)) {

	    !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&

	    !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {

		if (mark)

		if (mark)

			nfs_mark_delegation_referenced(delegation);

			nfs_mark_delegation_referenced(delegation);

		ret = 1;

		ret = 1;
@@ -894,7 +903,7 @@ bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags, 
	flags &= FMODE_READ|FMODE_WRITE;

	flags &= FMODE_READ|FMODE_WRITE;

	rcu_read_lock();

	rcu_read_lock();

	delegation = rcu_dereference(nfsi->delegation);

	delegation = rcu_dereference(nfsi->delegation);

	ret = (delegation != NULL && (delegation->type & flags) == flags);

	ret = nfs4_is_valid_delegation(delegation, flags);

	if (ret) {

	if (ret) {

		nfs4_stateid_copy(dst, &delegation->stateid);

		nfs4_stateid_copy(dst, &delegation->stateid);

		nfs_mark_delegation_referenced(delegation);

		nfs_mark_delegation_referenced(delegation);

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