[PATCH 5.12 115/296] NFS: Dont corrupt the value of pg_bytes_written in nfs_do_recoalesce()

Greg Kroah-Hartman
2021-05-31T16:17:00Z

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

commit 0d0ea309357dea0d85a82815f02157eb7fcda39f upstream.

The value of mirror->pg_bytes_written should only be updated after a
successful attempt to flush out the requests on the list.

Fixes: a7d42ddb3099 ("nfs: add mirroring support to pgio layer")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/nfs/pagelist.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1128,17 +1128,16 @@ static void nfs_pageio_doio(struct nfs_p
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);

-
if (!list_empty(&mirror->pg_list)) {
int error = desc->pg_ops->pg_doio(desc);
if (error < 0)
desc->pg_error = error;
- else
+ if (list_empty(&mirror->pg_list)) {
mirror->pg_bytes_written += mirror->pg_count;
- }
- if (list_empty(&mirror->pg_list)) {
- mirror->pg_count = 0;
- mirror->pg_base = 0;
+ mirror->pg_count = 0;
+ mirror->pg_base = 0;
+ mirror->pg_recoalesce = 0;
+ }
}
}

@@ -1228,7 +1227,6 @@ static int nfs_do_recoalesce(struct nfs_

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