From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Fri, 25 Mar 2022 21:51:03 -0400
Subject: [PATCH] NFS: Don't loop forever in nfs_do_recoalesce()
Git-commit: d02d81efc7564b4d5446a02e0214a164cf00b1f3
Patch-mainline: v5.18
References: git-fixes

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>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/pagelist.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1227,6 +1227,7 @@ static int nfs_do_recoalesce(struct nfs_
 
 	do {
 		list_splice_init(&mirror->pg_list, &head);
+		mirror->pg_recoalesce = 0;
 
 		while (!list_empty(&head)) {
 			struct nfs_page *req;