The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6b69040247e14b43419a520f841f2b3052833df9 Mon Sep 17 00:00:00 2001

From: Zhang Xiaoxu zhangxiaoxu5@huawei.com Date: Tue, 23 Jun 2020 07:31:54 -0400 Subject: [PATCH] cifs/smb3: Fix data inconsistent when zero file range

CIFS implements the fallocate(FALLOC_FL_ZERO_RANGE) with send SMB ioctl(FSCTL_SET_ZERO_DATA) to server. It just set the range of the remote file to zero, but local page cache not update, then the data inconsistent with server, which leads the xfstest generic/008 failed.

So we need to remove the local page caches before send SMB ioctl(FSCTL_SET_ZERO_DATA) to server. After next read, it will re-cache it.

Fixes: 30175628bf7f5 ("[SMB3] Enable fallocate -z support for SMB3 mounts") Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Zhang Xiaoxu zhangxiaoxu5@huawei.com Reviewed-by: Pavel Shilovsky pshilov@microsoft.com Cc: stable@vger.kernel.org # v3.17 Signed-off-by: Steve French stfrench@microsoft.com

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 28553d45604e..876a0d9e3d46 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -3188,6 +3188,11 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon, trace_smb3_zero_enter(xid, cfile->fid.persistent_fid, tcon->tid, ses->Suid, offset, len);

+ /* + * We zero the range through ioctl, so we need remove the page caches + * first, otherwise the data may be inconsistent with the server. + */ + truncate_pagecache_range(inode, offset, offset + len - 1);

/* if file not oplocked can't be sure whether asking to extend size */ if (!CIFS_CACHE_READ(cifsi))