Commit 319c1042 authored May 31, 2017 by Rabin Vincent Committed by Richard Weinberger Jul 14, 2017

ubifs: allow userspace to map mounts to volumes



There currently appears to be no way for userspace to find out the
underlying volume number for a mounted ubifs file system, since ubifs
uses anonymous block devices.  The volume name is present in
/proc/mounts but UBI volumes can be renamed after the volume has been
mounted.

To remedy this, show the UBI number and UBI volume number as part of the
options visible under /proc/mounts.

Also, accept and ignore the ubi= vol= options if they are used mounting
(patch from Richard Weinberger).

 # mount -t ubifs ubi:baz x
 # mount
 ubi:baz on /root/x type ubifs (rw,relatime,ubi=0,vol=2)
 # ubirename /dev/ubi0 baz bazz
 # mount
 ubi:baz on /root/x type ubifs (rw,relatime,ubi=0,vol=2)
 # ubinfo -d 0 -n 2
 Volume ID:   2 (on ubi0)
 Type:        dynamic
 Alignment:   1
 Size:        67 LEBs (1063424 bytes, 1.0 MiB)
 State:       OK
 Name:        bazz
 Character device major/minor: 254:3

Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

parent a02a6eba

fs/ubifs/super.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -446,6 +446,8 @@ static int ubifs_show_options(struct seq_file s, struct dentry root)
		ubifs_compr_name(c->mount_opts.compr_type));
		}

		seq_printf(s, ",ubi=%d,vol=%d", c->vi.ubi_num, c->vi.vol_id);

		return 0;
		}

		@@ -931,6 +933,7 @@ enum {
		Opt_chk_data_crc,
		Opt_no_chk_data_crc,
		Opt_override_compr,
		Opt_ignore,
		Opt_err,
		};

		@@ -942,6 +945,8 @@ static const match_table_t tokens = {
		{Opt_chk_data_crc, "chk_data_crc"},
		{Opt_no_chk_data_crc, "no_chk_data_crc"},
		{Opt_override_compr, "compr=%s"},
		{Opt_ignore, "ubi=%s"},
		{Opt_ignore, "vol=%s"},
		{Opt_err, NULL},
		};

		@@ -1042,6 +1047,8 @@ static int ubifs_parse_options(struct ubifs_info c, char options,
		c->default_compr = c->mount_opts.compr_type;
		break;
		}
		case Opt_ignore:
		break;
		default:
		{
		unsigned long flag;

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