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authorJ. Bruce Fields <bfields@redhat.com>2017-07-28 16:35:15 -0400
committerJ. Bruce Fields <bfields@redhat.com>2020-05-08 21:23:10 -0400
commit28df3d1539de5090f7916f6fff03891b67f366f4 (patch)
tree0a324005caeca12e5bb02384d7e30ddc655d9862 /fs/nfsd
parent52782c92ac85c4e393eb4a903a62e6c24afa633f (diff)
nfsd: clients don't need to break their own delegations
We currently revoke read delegations on any write open or any operation that modifies file data or metadata (including rename, link, and unlink). But if the delegation in question is the only read delegation and is held by the client performing the operation, that's not really necessary. It's not always possible to prevent this in the NFSv4.0 case, because there's not always a way to determine which client an NFSv4.0 delegation came from. (In theory we could try to guess this from the transport layer, e.g., by assuming all traffic on a given TCP connection comes from the same client. But that's not really correct.) In the NFSv4.1 case the session layer always tells us the client. This patch should remove such self-conflicts in all cases where we can reliably determine the client from the compound. To do that we need to track "who" is performing a given (possibly lease-breaking) file operation. We're doing that by storing the information in the svc_rqst and using kthread_data() to map the current task back to a svc_rqst. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfs4proc.c2
-rw-r--r--fs/nfsd/nfs4state.c14
-rw-r--r--fs/nfsd/nfsd.h2
-rw-r--r--fs/nfsd/nfssvc.c6
4 files changed, 24 insertions, 0 deletions
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 0e75f7fb5fec..a6d73aa51ce4 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2302,6 +2302,8 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
}
check_if_stalefh_allowed(args);
+ rqstp->rq_lease_breaker = (void **)&cstate->clp;
+
trace_nfsd_compound(rqstp, args->opcnt);
while (!status && resp->opcnt < args->opcnt) {
op = &args->ops[resp->opcnt++];
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index fe88f5f23cf4..31388046c6fe 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4579,6 +4579,19 @@ nfsd_break_deleg_cb(struct file_lock *fl)
return ret;
}
+static bool nfsd_breaker_owns_lease(struct file_lock *fl)
+{
+ struct nfs4_delegation *dl = fl->fl_owner;
+ struct svc_rqst *rqst;
+ struct nfs4_client *clp;
+
+ if (!i_am_nfsd())
+ return NULL;
+ rqst = kthread_data(current);
+ clp = *(rqst->rq_lease_breaker);
+ return dl->dl_stid.sc_client == clp;
+}
+
static int
nfsd_change_deleg_cb(struct file_lock *onlist, int arg,
struct list_head *dispose)
@@ -4590,6 +4603,7 @@ nfsd_change_deleg_cb(struct file_lock *onlist, int arg,
}
static const struct lock_manager_operations nfsd_lease_mng_ops = {
+ .lm_breaker_owns_lease = nfsd_breaker_owns_lease,
.lm_break = nfsd_break_deleg_cb,
.lm_change = nfsd_change_deleg_cb,
};
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 2ab5569126b8..36cdd81b6688 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -88,6 +88,8 @@ int nfsd_pool_stats_release(struct inode *, struct file *);
void nfsd_destroy(struct net *net);
+bool i_am_nfsd(void);
+
struct nfsdfs_client {
struct kref cl_ref;
void (*cl_release)(struct kref *kref);
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index ca9fd348548b..4f588c0eaaf4 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -601,6 +601,11 @@ static const struct svc_serv_ops nfsd_thread_sv_ops = {
.svo_module = THIS_MODULE,
};
+bool i_am_nfsd()
+{
+ return kthread_func(current) == nfsd;
+}
+
int nfsd_create_serv(struct net *net)
{
int error;
@@ -1011,6 +1016,7 @@ nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
*statp = rpc_garbage_args;
return 1;
}
+ rqstp->rq_lease_breaker = NULL;
/*
* Give the xdr decoder a chance to change this if it wants
* (necessary in the NFSv4.0 compound case)