2020-02-10 19:16:24

by Trond Myklebust

Subject: [PATCH 1/8] NFS: alloc_nfs_open_context() must use the file cred when available

If we're creating a nfs_open_context() for a specific file pointer,
we must use the cred assigned to that file.

Fixes: a52458b48af1 ("NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.")
Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/inode.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 11bf15800ac9..a10fb87c6ac3 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -959,16 +959,16 @@ struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry,
struct file *filp)
{
struct nfs_open_context *ctx;
- const struct cred *cred = get_current_cred();

ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
- if (!ctx) {
- put_cred(cred);
+ if (!ctx)
return ERR_PTR(-ENOMEM);
- }
nfs_sb_active(dentry->d_sb);
ctx->dentry = dget(dentry);
- ctx->cred = cred;
+ if (filp)
+ ctx->cred = get_cred(filp->f_cred);
+ else
+ ctx->cred = get_current_cred();
ctx->ll_cred = NULL;
ctx->state = NULL;
ctx->mode = f_mode;
--
2.24.1

2020-02-10 19:16:27

by Trond Myklebust

Subject: [PATCH 2/8] SUNRPC: Add a flag to avoid reference counts on credentials

Add a flag to signal to the RPC layer that the credential is already
pinned for the duration of the RPC call.

Signed-off-by: Trond Myklebust <[email protected]>
---
include/linux/sunrpc/sched.h | 1 +
net/sunrpc/clnt.c | 5 +++--
net/sunrpc/sched.c | 3 ++-
3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index a6ef35184ef1..df696efdd675 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -132,6 +132,7 @@ struct rpc_task_setup {
#define RPC_TASK_TIMEOUT 0x1000 /* fail with ETIMEDOUT on timeout */
#define RPC_TASK_NOCONNECT 0x2000 /* return ENOTCONN if not connected */
#define RPC_TASK_NO_RETRANS_TIMEOUT 0x4000 /* wait forever for a reply */
+#define RPC_TASK_CRED_NOREF 0x8000 /* No refcount on the credential */

#define RPC_IS_ASYNC(t) ((t)->tk_flags & RPC_TASK_ASYNC)
#define RPC_IS_SWAPPER(t) ((t)->tk_flags & RPC_TASK_SWAPPER)
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 7324b21f923e..2345e563c2f4 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1099,8 +1099,9 @@ rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
task->tk_msg.rpc_proc = msg->rpc_proc;
task->tk_msg.rpc_argp = msg->rpc_argp;
task->tk_msg.rpc_resp = msg->rpc_resp;
- if (msg->rpc_cred != NULL)
- task->tk_msg.rpc_cred = get_cred(msg->rpc_cred);
+ task->tk_msg.rpc_cred = msg->rpc_cred;
+ if (!(task->tk_flags & RPC_TASK_CRED_NOREF))
+ get_cred(task->tk_msg.rpc_cred);
}
}

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 55e900255b0c..6eff14119a88 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -1162,7 +1162,8 @@ static void rpc_release_resources_task(struct rpc_task *task)
{
xprt_release(task);
if (task->tk_msg.rpc_cred) {
- put_cred(task->tk_msg.rpc_cred);
+ if (!(task->tk_flags & RPC_TASK_CRED_NOREF))
+ put_cred(task->tk_msg.rpc_cred);
task->tk_msg.rpc_cred = NULL;
}
rpc_task_release_client(task);
--
2.24.1

2020-02-10 19:16:29

by Trond Myklebust

Subject: [PATCH 3/8] SUNRPC: Don't take a reference to the cred on synchronous tasks

If the RPC call is synchronous, assume the cred is already pinned
by the caller.

Signed-off-by: Trond Myklebust <[email protected]>
---
net/sunrpc/clnt.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 2345e563c2f4..252b044cdcdf 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1127,6 +1127,9 @@ struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)

task = rpc_new_task(task_setup_data);

+ if (!RPC_IS_ASYNC(task))
+ task->tk_flags |= RPC_TASK_CRED_NOREF;
+
rpc_task_set_client(task, task_setup_data->rpc_client);
rpc_task_set_rpc_message(task, task_setup_data->rpc_message);

--
2.24.1