linux-kernel - [PATCH] cifs: Fix copy offload to flush destination region

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <861652.1724773660@warthog.procyon.org.uk>
Date: Tue, 27 Aug 2024 16:47:40 +0100
From: David Howells <dhowells@...hat.com>
To: Steve French <stfrench@...rosoft.com>
cc: dhowells@...hat.com, Paulo Alcantara <pc@...guebit.com>,
    Shyam Prasad N <nspmangalore@...il.com>,
    Rohith Surabattula <rohiths.msft@...il.com>,
    Matthew Wilcox <willy@...radead.org>,
    Jeff Layton <jlayton@...nel.org>, linux-cifs@...r.kernel.org,
    linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
    linux-kernel@...r.kernel.org
Subject: [PATCH] cifs: Fix copy offload to flush destination region

    
Fix cifs_file_copychunk_range() to flush the destination region before
invalidating it to avoid potential loss of data should the copy fail, in
whole or in part, in some way.

Fixes: 7b2404a886f8 ("cifs: Fix flushing, invalidation and file size with copy_file_range()")
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Steve French <stfrench@...rosoft.com>
cc: Paulo Alcantara <pc@...guebit.com>
cc: Shyam Prasad N <nspmangalore@...il.com>
cc: Rohith Surabattula <rohiths.msft@...il.com>
cc: Matthew Wilcox <willy@...radead.org>
cc: Jeff Layton <jlayton@...nel.org>
cc: linux-cifs@...r.kernel.org
cc: linux-mm@...ck.org
cc: linux-fsdevel@...r.kernel.org
---
 fs/smb/client/cifsfs.c |   21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index d89485235425..2a2523c93944 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1341,7 +1341,6 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 	struct cifsFileInfo *smb_file_target;
 	struct cifs_tcon *src_tcon;
 	struct cifs_tcon *target_tcon;
-	unsigned long long destend, fstart, fend;
 	ssize_t rc;
 
 	cifs_dbg(FYI, "copychunk range\n");
@@ -1391,25 +1390,13 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 			goto unlock;
 	}
 
-	destend = destoff + len - 1;
-
-	/* Flush the folios at either end of the destination range to prevent
-	 * accidental loss of dirty data outside of the range.
+	/* Flush and invalidate all the folios in the destination region.  If
+	 * the copy was successful, then some of the flush is extra overhead,
+	 * but we need to allow for the copy failing in some way (eg. ENOSPC).
 	 */
-	fstart = destoff;
-	fend = destend;
-
-	rc = cifs_flush_folio(target_inode, destoff, &fstart, &fend, true);
+	rc = filemap_invalidate_inode(target_inode, true, destoff, destoff + len - 1);
 	if (rc)
 		goto unlock;
-	rc = cifs_flush_folio(target_inode, destend, &fstart, &fend, false);
-	if (rc)
-		goto unlock;
-	if (fend > target_cifsi->netfs.zero_point)
-		target_cifsi->netfs.zero_point = fend + 1;
-
-	/* Discard all the folios that overlap the destination region. */
-	truncate_inode_pages_range(&target_inode->i_data, fstart, fend);
 
 	fscache_invalidate(cifs_inode_cookie(target_inode), NULL,
 			   i_size_read(target_inode), 0);