On Mon, 28 Mar 2022 13:24:57 +0000, Trond Myklebust wrote:
Let's just do the following.
8<----------------------------------------------- From 7c9d845f0612e5bcd23456a2ec43be8ac43458f1 Mon Sep 17 00:00:00 2001 From: Trond Myklebust trond.myklebust@hammerspace.com Date: Mon, 28 Mar 2022 08:36:34 -0400 Subject: [PATCH] NFSv4/pNFS: Fix another issue with a list iterator pointing to the head
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@gmail.com Fixes: 1be5683b03a7 ("pnfs: CB_NOTIFY_DEVICEID") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com
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); --
Thank you, i have resend a PATCH v2 with fix as you suggested, and also with some changes, please check it.
-- Xiaomeng Tong