[PATCH v2] CIFS: check new file size when extending file by fallocate

[PATCH v2] CIFS: check new file size when extending file by fallocate

[Murphy Zhou]

xfstests generic/228 checks if fallocate respect RLIMIT_FSIZE.
After fallocate mode 0 extending enabled, we can hit this failure.
Fix this by check the new file size with vfs helper, return
error if file size is larger then RLIMIT_FSIZE(ulimit -f).

This patch has been tested by LTP/xfstests aginst samba and
Windows server.

Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
---

v2:
  Use (off+len) instead of eof for correct argument type

 fs/cifs/smb2ops.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index c31e84ee3c39..f221a01f62bd 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3246,6 +3246,10 @@ 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) {
+		rc = inode_newsize_ok(inode, off + len);
+		if (rc)
+			goto out;
+
 		if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0)
 			smb2_set_sparse(xid, tcon, cfile, inode, false);
 
-- 
2.20.1