[PATCH 5.17 0813/1126] NFS: Dont loop forever in nfs_do_recoalesce()

Greg Kroah-Hartman
2022-04-05T09:28:56Z

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

[ Upstream commit d02d81efc7564b4d5446a02e0214a164cf00b1f3 ]

If __nfs_pageio_add_request() fails to add the request, it will return
with either desc->pg_error < 0, or mirror->pg_recoalesce will be set, so
we are guaranteed either to exit the function altogether, or to loop.

However if there is nothing left in mirror->pg_list to coalesce, we must
exit, so make sure that we clear mirror->pg_recoalesce every time we
loop.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 70536bf4eb07 ("NFS: Clean up reset of the mirror accounting variables")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfs/pagelist.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index ad7f83dc9a2d..815d63080245 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1218,6 +1218,7 @@ static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)

do {
list_splice_init(&mirror->pg_list, &head);
+ mirror->pg_recoalesce = 0;

while (!list_empty(&head)) {
struct nfs_page *req;
--
2.34.1