Patch "NFS: Don't loop forever in nfs_do_recoalesce()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    NFS: Don't loop forever in nfs_do_recoalesce()

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfs-don-t-loop-forever-in-nfs_do_recoalesce.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b22ad4bcbc41b0fbaf845a9faeb9052c4b3eb5d1
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date:   Fri Mar 25 21:51:03 2022 -0400

    NFS: Don't loop forever in nfs_do_recoalesce()
    
    [ 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@xxxxxxxxx>
    Fixes: 70536bf4eb07 ("NFS: Clean up reset of the mirror accounting variables")
    Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index cc232d1f16f2..b1130dc200d2 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1227,6 +1227,7 @@ 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;