fuse: honor RLIMIT_FSIZE in fuse_file_fallocate

BugLink: https://bugs.launchpad.net/bugs/1832661

commit 0cbade02 upstream.

fstests generic/228 reported this failure that fuse fallocate does not
honor what 'ulimit -f' has set.

This adds the necessary inode_newsize_ok() check.
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Fixes: 05ba1f08 ("fuse: add FALLOCATE operation")
Cc: <stable@vger.kernel.org> # v3.5
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

fs/fuse/file.c

@@ -2959,6 +2959,13 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 		}
 	}
 
+	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+	    offset + length > i_size_read(inode)) {
+		err = inode_newsize_ok(inode, offset + length);
+		if (err)
+			return err;
+	}
+
 	if (!(mode & FALLOC_FL_KEEP_SIZE))
 		set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);