In nfs4_callback_devicenotify(), if we don't find a matching entry for
the deviceid, we're left with a pointer to 'struct nfs_server' that
actually points to the list of super blocks associated with our struct
nfs_client.
Furthermore, even if we have a valid pointer, nothing pins the super
block, and so the struct nfs_server could end up getting freed while
we're using it.
Since all we want is a pointer to the struct pnfs_layoutdriver_type,
let's skip all the iteration over super blocks, and just use APIs to
find the layout driver directly.
Reported-by: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
Fixes: 1be5683b03a7 ("pnfs: CB_NOTIFY_DEVICEID")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfs/callback_proc.c | 27 +++++++++------------------
fs/nfs/pnfs.c | 11 +++++++++++
fs/nfs/pnfs.h | 2 ++
3 files changed, 22 insertions(+), 18 deletions(-)
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 39d1ec870d90..c8520284dda7 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -358,12 +358,11 @@ __be32 nfs4_callback_devicenotify(void *argp, void *resp,
struct cb_process_state *cps)
{
struct cb_devicenotifyargs *args = argp;
+ const struct pnfs_layoutdriver_type *ld = NULL;
uint32_t i;
__be32 res = 0;
- struct nfs_client *clp = cps->clp;
- struct nfs_server *server = NULL;
- if (!clp) {
+ if (!cps->clp) {
res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
goto out;
}
@@ -371,23 +370,15 @@ __be32 nfs4_callback_devicenotify(void *argp, void *resp,
for (i = 0; i < args->ndevs; i++) {
struct cb_devicenotifyitem *dev = &args->devs[i];
- if (!server ||
- server->pnfs_curr_ld->id != dev->cbd_layout_type) {
- rcu_read_lock();
- list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
- if (server->pnfs_curr_ld &&
- server->pnfs_curr_ld->id == dev->cbd_layout_type) {
- rcu_read_unlock();
- goto found;
- }
- rcu_read_unlock();
- continue;
+ if (!ld || ld->id != dev->cbd_layout_type) {
+ pnfs_put_layoutdriver(ld);
+ ld = pnfs_find_layoutdriver(dev->cbd_layout_type);
+ if (!ld)
+ continue;
}
-
- found:
- nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id);
+ nfs4_delete_deviceid(ld, cps->clp, &dev->cbd_dev_id);
}
-
+ pnfs_put_layoutdriver(ld);
out:
kfree(args->devs);
return res;
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index de318bb5d349..856c962273c7 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -92,6 +92,17 @@ find_pnfs_driver(u32 id)
return local;
}
+const struct pnfs_layoutdriver_type *pnfs_find_layoutdriver(u32 id)
+{
+ return find_pnfs_driver(id);
+}
+
+void pnfs_put_layoutdriver(const struct pnfs_layoutdriver_type *ld)
+{
+ if (ld)
+ module_put(ld->owner);
+}
+
void
unset_pnfs_layoutdriver(struct nfs_server *nfss)
{
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index f4d7548d67b2..07f11489e4e9 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -234,6 +234,8 @@ struct pnfs_devicelist {
extern int pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *);
extern void pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *);
+extern const struct pnfs_layoutdriver_type *pnfs_find_layoutdriver(u32 id);
+extern void pnfs_put_layoutdriver(const struct pnfs_layoutdriver_type *ld);
/* nfs4proc.c */
extern size_t max_response_pages(struct nfs_server *server);
--
2.35.1
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
