[PATCH 5.2 105/143] NFS: Ensure O_DIRECT reports an error if the bytes read/written is 0

From: Greg Kroah-Hartman
Date: Wed Sep 04 2019 - 14:15:26 EST


From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>

commit eb2c50da9e256dbbb3ff27694440e4c1900cfef8 upstream.

If the attempt to resend the I/O results in no bytes being read/written,
we must ensure that we report the error.

Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Fixes: 0a00b77b331a ("nfs: mirroring support for direct io")
Cc: stable@xxxxxxxxxxxxxxx # v3.20+
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/nfs/direct.c | 27 ++++++++++++++++++---------
fs/nfs/pagelist.c | 1 +
2 files changed, 19 insertions(+), 9 deletions(-)

--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -401,15 +401,21 @@ static void nfs_direct_read_completion(s
unsigned long bytes = 0;
struct nfs_direct_req *dreq = hdr->dreq;

- if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
- goto out_put;
-
spin_lock(&dreq->lock);
- if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes == 0))
+ if (test_bit(NFS_IOHDR_ERROR, &hdr->flags))
dreq->error = hdr->error;
- else
+
+ if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) {
+ spin_unlock(&dreq->lock);
+ goto out_put;
+ }
+
+ if (hdr->good_bytes != 0)
nfs_direct_good_bytes(dreq, hdr);

+ if (test_bit(NFS_IOHDR_EOF, &hdr->flags))
+ dreq->error = 0;
+
spin_unlock(&dreq->lock);

while (!list_empty(&hdr->pages)) {
@@ -782,16 +788,19 @@ static void nfs_direct_write_completion(
bool request_commit = false;
struct nfs_page *req = nfs_list_entry(hdr->pages.next);

- if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
- goto out_put;
-
nfs_init_cinfo_from_dreq(&cinfo, dreq);

spin_lock(&dreq->lock);

if (test_bit(NFS_IOHDR_ERROR, &hdr->flags))
dreq->error = hdr->error;
- if (dreq->error == 0) {
+
+ if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) {
+ spin_unlock(&dreq->lock);
+ goto out_put;
+ }
+
+ if (hdr->good_bytes != 0) {
nfs_direct_good_bytes(dreq, hdr);
if (nfs_write_need_commit(hdr)) {
if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES)
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1268,6 +1268,7 @@ int nfs_pageio_resend(struct nfs_pageio_
if (!list_empty(&pages)) {
int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
hdr->completion_ops->error_cleanup(&pages, err);
+ nfs_set_pgio_error(hdr, err, hdr->io_start);
return err;
}
return 0;