NFS: Fix an Oopsable condition in __nfs_pageio_add_request()

commit 56517ab958b7c11030e626250c00b9b1a24b41eb upstream.

Ensure that nfs_pageio_error_cleanup() resets the mirror array contents,
so that the structure reflects the fact that it is now empty.
Also change the test in nfs_pageio_do_add_request() to be more robust by
checking whether or not the list is empty rather than relying on the
value of pg_count.

Fixes: a7d42ddb30 ("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>
This commit is contained in:
Trond Myklebust 2021-05-25 10:23:05 -04:00 committed by Greg Kroah-Hartman
parent 9b367fe770
commit ee21cd3aa8

View File

@ -1094,15 +1094,16 @@ nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *prev = NULL;
unsigned int size;
if (mirror->pg_count != 0) {
prev = nfs_list_entry(mirror->pg_list.prev);
} else {
if (list_empty(&mirror->pg_list)) {
if (desc->pg_ops->pg_init)
desc->pg_ops->pg_init(desc, req);
if (desc->pg_error < 0)
return 0;
mirror->pg_base = req->wb_pgbase;
}
mirror->pg_count = 0;
mirror->pg_recoalesce = 0;
} else
prev = nfs_list_entry(mirror->pg_list.prev);
if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {
if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)