2021-05-25 18:34:27

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v2 2/3] NFS: Don't corrupt the value of pg_bytes_written in nfs_do_recoalesce()

From: Trond Myklebust <[email protected]>

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 <[email protected]>
---
fs/nfs/pagelist.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d35c84af44e0..daf6658517f4 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1128,17 +1128,16 @@ static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
{
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_pageio_descriptor *desc)

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;
--
2.31.1