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NFSv4: Don't allow a cached open with a revoked delegation 

If the delegation is marked as being revoked, we must not use it
for cached opens.

Fixes: 869f9dfa4d ("NFSv4: Fix races between nfs_remove_bad_delegation() and delegation return")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Trond Myklebust 2019-10-31 18:40:32 -04:00 committed by Anna Schumaker
parent 669996add4
commit be3df3dd4c
3 changed files with 13 additions and 5 deletions
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10
fs/nfs/delegation.c
View File

@ -53,6 +53,16 @@ nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
return false;
}
struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
{
struct nfs_delegation *delegation;
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (nfs4_is_valid_delegation(delegation, 0))
return delegation;
return NULL;
}
static int
nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
{

1
fs/nfs/delegation.h
View File

@ -68,6 +68,7 @@ int nfs4_lock_delegation_recall(struct file_lock *fl, struct nfs4_state *state,
bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags, nfs4_stateid *dst, const struct cred **cred);
bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode);
struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode);
void nfs_mark_delegation_referenced(struct nfs_delegation *delegation);
int nfs4_have_delegation(struct inode *inode, fmode_t flags);
int nfs4_check_delegation(struct inode *inode, fmode_t flags);

7
fs/nfs/nfs4proc.c
View File

@ -1440,8 +1440,6 @@ static int can_open_delegated(struct nfs_delegation *delegation, fmode_t fmode,
return 0;
if ((delegation->type & fmode) != fmode)
return 0;
if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
return 0;
switch (claim) {
case NFS4_OPEN_CLAIM_NULL:
case NFS4_OPEN_CLAIM_FH:
@ -1810,7 +1808,6 @@ static void nfs4_return_incompatible_delegation(struct inode *inode, fmode_t fmo
static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
{
struct nfs4_state *state = opendata->state;
struct nfs_inode *nfsi = NFS_I(state->inode);
struct nfs_delegation *delegation;
int open_mode = opendata->o_arg.open_flags;
fmode_t fmode = opendata->o_arg.fmode;
@ -1827,7 +1824,7 @@ static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
}
spin_unlock(&state->owner->so_lock);
rcu_read_lock();
delegation = rcu_dereference(nfsi->delegation);
delegation = nfs4_get_valid_delegation(state->inode);
if (!can_open_delegated(delegation, fmode, claim)) {
rcu_read_unlock();
break;
@ -2371,7 +2368,7 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
data->o_arg.open_flags, claim))
goto out_no_action;
rcu_read_lock();
delegation = rcu_dereference(NFS_I(data->state->inode)->delegation);
delegation = nfs4_get_valid_delegation(data->state->inode);
if (can_open_delegated(delegation, data->o_arg.fmode, claim))
goto unlock_no_action;
rcu_read_unlock();