[PATCH 4.7 091/186] nfs: dont create zero-length requests
From: Greg Kroah-Hartman
Date: Thu Aug 18 2016 - 10:39:05 EST
4.7-stable review patch. If anyone has any objections, please let me know.
------------------
From: Benjamin Coddington <bcodding@xxxxxxxxxx>
commit 149a4fddd0a72d526abbeac0c8deaab03559836a upstream.
NFS doesn't expect requests with wb_bytes set to zero and may make
unexpected decisions about how to handle that request at the page IO layer.
Skip request creation if we won't have any wb_bytes in the request.
Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Reviewed-by: Weston Andros Adamson <dros@xxxxxxxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/write.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1289,6 +1289,9 @@ int nfs_updatepage(struct file *file, st
dprintk("NFS: nfs_updatepage(%pD2 %d@%lld)\n",
file, count, (long long)(page_file_offset(page) + offset));
+ if (!count)
+ goto out;
+
if (nfs_can_extend_write(file, page, inode)) {
count = max(count + offset, nfs_page_length(page));
offset = 0;
@@ -1299,7 +1302,7 @@ int nfs_updatepage(struct file *file, st
nfs_set_pageerror(page);
else
__set_page_dirty_nobuffers(page);
-
+out:
dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n",
status, (long long)i_size_read(inode));
return status;