[PATCH 5.10 155/243] NFSv4: Fix an Oops in pnfs_mark_request_commit() when doing O_DIRECT

Greg Kroah-Hartman
2021-07-19T17:22:48Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit 3731d44bba8e0116b052b1b374476c5f6dd9a456 ]

Fix an Oopsable condition in pnfs_mark_request_commit() when we're
putting a set of writes on the commit list to reschedule them after a
failed pNFS attempt.

Fixes: 9c455a8c1e14 ("NFS/pNFS: Clean up pNFS commit operations")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfs/direct.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 2d30a4da49fa..2e894fec036b 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -700,8 +700,8 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
{
struct nfs_direct_req *dreq = hdr->dreq;
struct nfs_commit_info cinfo;
- bool request_commit = false;
struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+ int flags = NFS_ODIRECT_DONE;

nfs_init_cinfo_from_dreq(&cinfo, dreq);

@@ -713,15 +713,9 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)

nfs_direct_count_bytes(dreq, hdr);
if (hdr->good_bytes != 0 && nfs_write_need_commit(hdr)) {
- switch (dreq->flags) {
- case 0:
+ if (!dreq->flags)
dreq->flags = NFS_ODIRECT_DO_COMMIT;
- request_commit = true;
- break;
- case NFS_ODIRECT_RESCHED_WRITES:
- case NFS_ODIRECT_DO_COMMIT:
- request_commit = true;
- }
+ flags = dreq->flags;
}
spin_unlock(&dreq->lock);

@@ -729,12 +723,15 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)

req = nfs_list_entry(hdr->pages.next);
nfs_list_remove_request(req);
- if (request_commit) {
+ if (flags == NFS_ODIRECT_DO_COMMIT) {
kref_get(&req->wb_kref);
memcpy(&req->wb_verf, &hdr->verf.verifier,
sizeof(req->wb_verf));
nfs_mark_request_commit(req, hdr->lseg, &cinfo,
hdr->ds_commit_idx);
+ } else if (flags == NFS_ODIRECT_RESCHED_WRITES) {
+ kref_get(&req->wb_kref);
+ nfs_mark_request_commit(req, NULL, &cinfo, 0);
}
nfs_unlock_and_release_request(req);
}
--
2.30.2