btrfs: correctly escape subvol in btrfs_show_options()

commit dc08c58696f8555e4a802f1f23c894a330d80ab7 upstream.

Currently, displaying the btrfs subvol mount option doesn't escape ','.
This makes parsing /proc/self/mounts and /proc/self/mountinfo
ambiguous for subvolume names that contain commas. The text after the
comma could be mistaken for another option (think "subvol=foo,ro", where
ro is actually part of the subvolumes name).

Replace the manual escape characters list with a call to
seq_show_option(). Thanks to Calvin Walton for suggesting this approach.

Fixes: c8d3fe028f ("Btrfs: show subvol= and subvolid= in /proc/mounts")
CC: stable@vger.kernel.org # 5.4+
Suggested-by: Calvin Walton <calvin.walton@kepstin.ca>
Signed-off-by: Johannes Kimmel <kernel@bareminimum.eu>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johannes Kimmel
2025-03-19 22:49:00 +01:00
committed by Greg Kroah-Hartman
parent b62b1406bb
commit d3995ff08c

View File

@@ -1140,8 +1140,7 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
subvol_name = btrfs_get_subvol_name_from_objectid(info,
btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
if (!IS_ERR(subvol_name)) {
seq_puts(seq, ",subvol=");
seq_escape(seq, subvol_name, " \t\n\\");
seq_show_option(seq, "subvol", subvol_name);
kfree(subvol_name);
}
return 0;