We must not touch the idmap->idmap_key_cons field when a downcall
is in progress. Set up a mutex and helper functions to ensure that
we wait until the downcall is finished.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Cc: Bryan Schumaker <bjschuma@xxxxxxxxxx>
---
fs/nfs/idmap.c | 65 ++++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 45 insertions(+), 20 deletions(-)
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index a850079..7c7072a 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -59,6 +59,7 @@ struct idmap {
struct rpc_pipe *idmap_pipe;
struct key_construction *idmap_key_cons;
struct mutex idmap_mutex;
+ struct mutex idmap_downcall_mutex;
};
struct idmap_legacy_upcalldata {
@@ -330,7 +331,6 @@ static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
name, namelen, type, data,
data_size, idmap);
- idmap->idmap_key_cons = NULL;
mutex_unlock(&idmap->idmap_mutex);
}
return ret;
@@ -485,6 +485,7 @@ nfs_idmap_new(struct nfs_client *clp)
}
idmap->idmap_pipe = pipe;
mutex_init(&idmap->idmap_mutex);
+ mutex_init(&idmap->idmap_downcall_mutex);
clp->cl_idmap = idmap;
return 0;
@@ -665,6 +666,32 @@ out:
return ret;
}
+static void
+nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
+ struct key_construction *cons)
+{
+ mutex_lock(&idmap->idmap_downcall_mutex);
+ WARN_ON_ONCE(idmap->idmap_key_cons != NULL);
+ idmap->idmap_key_cons = cons;
+ mutex_unlock(&idmap->idmap_downcall_mutex);
+}
+
+static void
+nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
+{
+ complete_request_key(idmap->idmap_key_cons, ret);
+ idmap->idmap_key_cons = NULL;
+}
+
+static void
+nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
+{
+ mutex_lock(&idmap->idmap_downcall_mutex);
+ if (idmap->idmap_key_cons != NULL)
+ nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+ mutex_unlock(&idmap->idmap_downcall_mutex);
+}
+
static int nfs_idmap_legacy_upcall(struct key_construction *cons,
const char *op,
void *aux)
@@ -689,17 +716,14 @@ static int nfs_idmap_legacy_upcall(struct key_construction *cons,
if (ret < 0)
goto out2;
- BUG_ON(idmap->idmap_key_cons != NULL);
- idmap->idmap_key_cons = cons;
-
+ nfs_idmap_prepare_pipe_upcall(idmap, cons);
ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
- if (ret < 0)
- goto out3;
+ if (ret < 0) {
+ nfs_idmap_abort_pipe_upcall(idmap, ret);
+ kfree(data);
+ }
return ret;
-
-out3:
- idmap->idmap_key_cons = NULL;
out2:
kfree(data);
out1:
@@ -740,14 +764,16 @@ idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
struct key_construction *cons;
struct idmap_msg im;
size_t namelen_in;
- int ret;
+ int ret = -ENOKEY;
/* If instantiation is successful, anyone waiting for key construction
* will have been woken up and someone else may now have used
* idmap_key_cons - so after this point we may no longer touch it.
*/
- cons = ACCESS_ONCE(idmap->idmap_key_cons);
- idmap->idmap_key_cons = NULL;
+ mutex_lock(&idmap->idmap_downcall_mutex);
+ cons = idmap->idmap_key_cons;
+ if (cons == NULL)
+ goto out_unlock;
if (mlen != sizeof(im)) {
ret = -ENOSPC;
@@ -777,7 +803,9 @@ idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
}
out:
- complete_request_key(cons, ret);
+ nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+out_unlock:
+ mutex_unlock(&idmap->idmap_downcall_mutex);
return ret;
}
@@ -788,12 +816,8 @@ idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
struct idmap_legacy_upcalldata,
pipe_msg);
struct idmap *idmap = data->idmap;
- struct key_construction *cons;
- if (msg->errno) {
- cons = ACCESS_ONCE(idmap->idmap_key_cons);
- idmap->idmap_key_cons = NULL;
- complete_request_key(cons, msg->errno);
- }
+ if (msg->errno)
+ nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
/* Free memory allocated in nfs_idmap_legacy_upcall() */
kfree(data);
}
@@ -803,7 +827,8 @@ idmap_release_pipe(struct inode *inode)
{
struct rpc_inode *rpci = RPC_I(inode);
struct idmap *idmap = (struct idmap *)rpci->private;
- idmap->idmap_key_cons = NULL;
+
+ nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
}
int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *uid)
--
1.7.11.4
--
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