[PATCH] CIFS: check new file size when extending file by fallocate

From: Murphy Zhou <jencce.kernel@gmail.com>
To: linux-cifs@vger.kernel.org
Cc: Ronnie Sahlberg <lsahlber@redhat.com>, Steve French <sfrench@samba.org>
Subject: [PATCH] CIFS: check new file size when extending file by fallocate
Date: Wed, 18 Mar 2020 09:56:24 +0800	[thread overview]
Message-ID: <20200318015624.spmlc7izbszkpdqf@xzhoux.usersys.redhat.com> (raw)

xfstests generic/228 checks if fallocate respects RLIMIT_FSIZE.
After fallocate mode 0 extending enabled, cifs can hit this failure.
Fix this by checking the new file size with the vfs helper, which
checks with RLIMIT_FSIZE(ulimit -f) and s_maxbytes.

This patch has been tested by LTP/xfstests aginst samba and
Windows server. No new issue was found.

Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
---
 fs/cifs/smb2ops.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index c31e84ee3c39..48bbbb68540d 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3246,10 +3246,14 @@ static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
 	 * Extending the file
 	 */
 	if ((keep_size == false) && i_size_read(inode) < off + len) {
+		eof = cpu_to_le64(off + len);
+		rc = inode_newsize_ok(inode, eof);
+		if (rc)
+			goto out;
+
 		if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0)
 			smb2_set_sparse(xid, tcon, cfile, inode, false);
 
-		eof = cpu_to_le64(off + len);
 		rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
 				  cfile->fid.volatile_fid, cfile->pid, &eof);
 		if (rc == 0) {
-- 
2.20.1
