netdev - [PATCH v4 04/13] cifs: Set zero_point in the copy_file_range() and remap_file

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Message-ID: <20231213154139.432922-5-dhowells@redhat.com>
Date: Wed, 13 Dec 2023 15:41:30 +0000
From: David Howells <dhowells@...hat.com>
To: Jeff Layton <jlayton@...nel.org>,
	Steve French <smfrench@...il.com>
Cc: David Howells <dhowells@...hat.com>,
	Matthew Wilcox <willy@...radead.org>,
	Paulo Alcantara <pc@...guebit.com>,
	Shyam Prasad N <sprasad@...rosoft.com>,
	Tom Talpey <tom@...pey.com>,
	Christian Brauner <christian@...uner.io>,
	linux-cachefs@...hat.com,
	linux-afs@...ts.infradead.org,
	linux-cifs@...r.kernel.org,
	linux-nfs@...r.kernel.org,
	ceph-devel@...r.kernel.org,
	v9fs@...ts.linux.dev,
	linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Steve French <sfrench@...ba.org>,
	Shyam Prasad N <nspmangalore@...il.com>,
	Rohith Surabattula <rohiths.msft@...il.com>
Subject: [PATCH v4 04/13] cifs: Set zero_point in the copy_file_range() and remap_file_range()

Set zero_point in the copy_file_range() and remap_file_range()
implementations so that we don't skip reading data modified on a
server-side copy.

Signed-off-by: David Howells <dhowells@...hat.com>
cc: Steve French <sfrench@...ba.org>
cc: Shyam Prasad N <nspmangalore@...il.com>
cc: Rohith Surabattula <rohiths.msft@...il.com>
cc: Jeff Layton <jlayton@...nel.org>
cc: linux-cifs@...r.kernel.org
cc: linux-cachefs@...hat.com
cc: linux-fsdevel@...r.kernel.org
cc: linux-mm@...ck.org
---
 fs/smb/client/cifsfs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index 078cff36cd2e..ebe04c78a955 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1337,6 +1337,8 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 	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. */
 	cifs_dbg(FYI, "about to discard pages %llx-%llx\n", fstart, fend);
@@ -1355,6 +1357,8 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 			fscache_resize_cookie(cifs_inode_cookie(target_inode),
 					      new_size);
 		}
+		if (rc == 0 && new_size > target_cifsi->netfs.zero_point)
+			target_cifsi->netfs.zero_point = new_size;
 	}
 
 	/* force revalidate of size and timestamps of target file now
@@ -1446,6 +1450,8 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 	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);