From 57c55cd7c77b81827757fdbe8dda8c3927c52b4e Mon Sep 17 00:00:00 2001
From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Thu, 24 May 2018 06:54:27 +1000
Subject: [PATCH] cifs: invalidate cache when we truncate a file
Git-commit: 57c55cd7c77b81827757fdbe8dda8c3927c52b4e
Patch-mainline: v4.18-rc1
References: bsc#1051510, bsc#1144333

RHBZ: 1566345

When truncating a file we always do this synchronously to the server.
Thus we need to make sure that the cached inode metadata is
marked as stale so that on next getattr we will refresh the metadata.
In this particular bug we want to ensure that both ctime and mtime
are updated and become visible to the application after a truncate.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
 fs/cifs/inode.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 3c371f7f5963..745fd7fe8d0e 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -746,7 +746,8 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
 	cifs_dbg(FYI, "Getting info on %s\n", full_path);
 
 	if ((data == NULL) && (*inode != NULL)) {
-		if (CIFS_CACHE_READ(CIFS_I(*inode))) {
+		if (CIFS_CACHE_READ(CIFS_I(*inode)) &&
+		    CIFS_I(*inode)->time != 0) {
 			cifs_dbg(FYI, "No need to revalidate cached inode sizes\n");
 			goto cgii_exit;
 		}
@@ -1857,15 +1858,15 @@ cifs_inode_needs_reval(struct inode *inode)
 	struct cifsInodeInfo *cifs_i = CIFS_I(inode);
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 
+	if (cifs_i->time == 0)
+		return true;
+
 	if (CIFS_CACHE_READ(cifs_i))
 		return false;
 
 	if (!lookupCacheEnabled)
 		return true;
 
-	if (cifs_i->time == 0)
-		return true;
-
 	if (!cifs_sb->actimeo)
 		return true;
 
@@ -2104,10 +2105,14 @@ static int cifs_truncate_page(struct address_space *mapping, loff_t from)
 
 static void cifs_setsize(struct inode *inode, loff_t offset)
 {
+	struct cifsInodeInfo *cifs_i = CIFS_I(inode);
+
 	spin_lock(&inode->i_lock);
 	i_size_write(inode, offset);
 	spin_unlock(&inode->i_lock);
 
+	/* Cached inode must be refreshed on truncate */
+	cifs_i->time = 0;
 	truncate_pagecache(inode, offset);
 }
 
-- 
2.16.4