[linux-lvm] [PATCH 0/2] dmsetup: add bootformat support

[linux-lvm] [PATCH 0/2] dmsetup: add bootformat support

[Enric Balletbo i Serra]

Dear all,

Recently we had some IRC discussion about adding support for a new string
format to create multiple devices in one line so we can use this new format
as a kernel cmdline parameter to create device-mapped devices without a
initramfs.

This first patchset is a first proposal for this new format, I'm either
interested on, know you opinion about the new format and know if the way
I introduced this new option is right or not. Is the first time I play with
this code so take this as first draft.

Bootformat is specified as a simple string of data separated by commas and
optionally semi-colons, where:
 - a comma is used to separate fields like name, uuid, mode and table (specifies
   one device)
 - a semi-colon is used to separate devices.

So the format will look like this:

 <dev_name>,<uuid>,<mode>,<table>[,<table>+][;<dev_name>,<uuid>,<mode>,<table>[,<table>+]]+

See the following example.

To supply the new format to dmsetup (splitted in multiple lines for readibility)

 $ dmsetup -v create --bootformat "lroot,none,rw, \
    0 2097152 linear 7:0 0,\
    2097152 2097152 linear 7:1 0,\
    4194304 2097152 linear 7:2 0;\
    mroot,,rw,\
    0 2097152 linear 7:3 0;\
    kroot,,rw,\
    0 2097152 linear 7:4 0"

Name:              lroot
State:             ACTIVE
Read Ahead:        256
Tables present:    LIVE
Open count:        0
Event number:      0
Major, minor:      253, 3
Number of targets: 3
UUID: none

Name:              mroot
State:             ACTIVE
Read Ahead:        256
Tables present:    LIVE
Open count:        0
Event number:      0
Major, minor:      253, 4
Number of targets: 1

Name:              kroot
State:             ACTIVE
Read Ahead:        256
Tables present:    LIVE
Open count:        0
Event number:      0
Major, minor:      253, 5
Number of targets: 1

To ask dmsetup to display your existing devices in this format:

 $ dmsetup table --bootformat lroot mroot kroot

lroot,none,rw,4194304 2097152 linear 7:2 0;mroot,,rw,0 2097152 linear 7:3 0;kroot,,rw,0 2097152 linear 7:4 0;

Finally I know that the code needs more work but I'm wonder if you expect
something like this or if I'm following the wrong way.

Next thing to do:
 - support embedded '\,' and '\;' among the other escaped options altready
   supported in string data

Waiting for your feedback,

Enric Balletbo i Serra (2):
  dmsetup: add support to output devices in bootformat style
  dmsetup: add support to create devices when bootformat is used

 tools/dmsetup.c | 155 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 153 insertions(+), 2 deletions(-)

-- 
2.9.3

[linux-lvm] [PATCH 1/2] dmsetup: add support to output devices in bootformat style

[Enric Balletbo i Serra]

Add a new parameter to be able to output the bootformat of one or more
devices. The bootformat for a device can be obtained by doing a:

 dmsetup table <device...> --bootformat

where device can be a specific device, a list of the devices or empty
for all devices. The output will look like this:

 <dev_name>,<uuid>,<mode>,<table>[,<table>+][;<dev_name>,<uuid>,<mode>,<table>[,<table>+]]+

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---
 tools/dmsetup.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/tools/dmsetup.c b/tools/dmsetup.c
index 5c5c14c..fc99145 100644
--- a/tools/dmsetup.c
+++ b/tools/dmsetup.c
@@ -163,6 +163,7 @@ enum {
 	AREA_ARG,
 	AREAS_ARG,
 	AREA_SIZE_ARG,
+	BOOTFORMAT_ARG,
 	BOUNDS_ARG,
 	CHECKS_ARG,
 	CLEAR_ARG,
@@ -2127,6 +2128,9 @@ static int _status(CMD_ARGS)
 	int matched = 0;
 	int ls_only = 0;
 	struct dm_info info;
+	const char *uuid = NULL;
+	char bootstr[LINE_SIZE] = {0};
+	int len;
 
 	if (names)
 		name = names->name;
@@ -2171,6 +2175,9 @@ static int _status(CMD_ARGS)
 	if (!name)
 		name = dm_task_get_name(dmt);
 
+	if (!uuid)
+		uuid = dm_task_get_uuid(dmt);
+
 	/* Fetch targets and print 'em */
 	do {
 		next = dm_get_next_target(dmt, next, &start, &length,
@@ -2184,6 +2191,20 @@ static int _status(CMD_ARGS)
 			    _switches[VERBOSE_ARG])
 				_display_dev(dmt, name);
 			next = NULL;
+		} else if (_switches[BOOTFORMAT_ARG]) {
+			if (!dm_snprintf(bootstr, sizeof(bootstr), "%s,%s,%s",
+					 dm_task_get_name(dmt), uuid,
+					 info.read_only ? "ro" : "rw"))
+				goto_out;
+			if (target_type) {
+				len = strlen(bootstr);
+				if (!dm_snprintf(bootstr + len,
+						 sizeof(bootstr) - len,
+						 "," FMTu64 " " FMTu64 " %s %s",
+						 start, length, target_type,
+						 params))
+					goto_out;
+			}
 		} else if (!_switches[EXEC_ARG] || !_command_to_exec ||
 			   _switches[VERBOSE_ARG]) {
 			if (!matched && _switches[VERBOSE_ARG])
@@ -2218,6 +2239,9 @@ static int _status(CMD_ARGS)
 		matched = 1;
 	} while (next);
 
+	if (matched && _switches[BOOTFORMAT_ARG])
+		printf("%s;", bootstr);
+
 	if (multiple_devices && _switches[VERBOSE_ARG] && matched && !ls_only)
 		putchar('\n');
 
@@ -5903,7 +5927,9 @@ static struct command _dmsetup_commands[] = {
 	{"deps", "[-o <options>] [<device>...]", 0, -1, 1, 0, _deps},
 	{"stats", "<command> [<options>] [<device>...]", 1, -1, 1, 1, _stats},
 	{"status", "[<device>...] [--noflush] [--target <target_type>]", 0, -1, 1, 0, _status},
-	{"table", "[<device>...] [--target <target_type>] [--showkeys]", 0, -1, 1, 0, _status},
+	{"table", "[<device>...]\n"
+	   "\t    [--target <target_type>] [--showkeys]\n"
+	   "\t    [--bootformat]", 0, -1, 1, 0, _status},
 	{"wait", "<device> [<event_nr>] [--noflush]", 0, 2, 0, 0, _wait},
 	{"mknodes", "[<device>...]", 0, -1, 1, 0, _mknodes},
 	{"mangle", "[<device>...]", 0, -1, 1, 0, _mangle},
@@ -6468,6 +6494,7 @@ static int _process_switches(int *argcp, char ***argvp, const char *dev_dir)
 		{"area", 0, &ind, AREA_ARG},
 		{"areas", 1, &ind, AREAS_ARG},
 		{"areasize", 1, &ind, AREA_SIZE_ARG},
+		{"bootformat", 0, &ind, BOOTFORMAT_ARG},
 		{"bounds", 1, &ind, BOUNDS_ARG},
 		{"checks", 0, &ind, CHECKS_ARG},
 		{"clear", 0, &ind, CLEAR_ARG},
@@ -6636,6 +6663,8 @@ static int _process_switches(int *argcp, char ***argvp, const char *dev_dir)
 			return_0;
 		if (c == 'h' || ind == HELP_ARG)
 			_switches[HELP_ARG]++;
+		if (ind == BOOTFORMAT_ARG)
+			_switches[BOOTFORMAT_ARG]++;
 		if (ind == BOUNDS_ARG) {
 			_switches[BOUNDS_ARG]++;
 			_string_args[BOUNDS_ARG] = optarg;
-- 
2.9.3

[linux-lvm] [PATCH 2/2] dmsetup: add support to create devices when bootformat is used

[Enric Balletbo i Serra]

Add a new switch to supply a bootformated string to dmsetup, we
support create one or multiple devices in one line provided to
the create command. E.g.

  dmsetup create --bootformat <multi_dev_info>|<multi_dev_info_file>

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---
 tools/dmsetup.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 123 insertions(+), 1 deletion(-)

diff --git a/tools/dmsetup.c b/tools/dmsetup.c
index fc99145..0961e65 100644
--- a/tools/dmsetup.c
+++ b/tools/dmsetup.c
@@ -1097,6 +1097,116 @@ out:
 	return r;
 }
 
+static int _parse_device(char *dev_info)
+{
+	int r = 0;
+	struct dm_task *dmt;
+	uint32_t cookie = 0;
+	uint16_t udev_flags = 0;
+	int line = 0, field = 0;
+	char *str = dev_info, *ptr = dev_info;
+
+	if (!(dmt = dm_task_create(DM_DEVICE_CREATE)))
+		return_0;
+
+	/*
+	 * FIXME: support embedded '\,' in string data:
+	 *   s/strsep/_find_unescaped_comma()/
+	 */
+	while ((str = strsep(&ptr, ",")) != NULL ) {
+		switch (field) {
+		case 0: /* set device name */
+			if (!dm_task_set_name(dmt, str))
+				goto_out;
+                        break;
+		case 1: /* set uuid if any */
+			if (strlen(str) && !dm_task_set_uuid(dmt, str))
+				goto_out;
+			break;
+		case 2:
+			if (!strncmp(str, "rw", strlen(str)))
+				break;
+			/* set as read-only if flags = "ro" | "" */
+			if (!strncmp(str, "ro", strlen(str)) ||
+			    !strncmp(str, "", strlen(str))) {
+				if (!dm_task_set_ro(dmt))
+					goto_out;
+			} else
+				goto_out;
+			break;
+		default:
+			if (!_parse_line(dmt, str, "", line++))
+				goto_out;
+			break;
+		}
+		field++;
+	}
+
+	if (field < 4)
+		goto_out;
+
+	if (!_set_task_add_node(dmt))
+		goto_out;
+
+	if (_udev_cookie)
+		cookie = _udev_cookie;
+
+	if (_udev_only)
+		udev_flags |= DM_UDEV_DISABLE_LIBRARY_FALLBACK;
+
+	if (!dm_task_set_cookie(dmt, &cookie, udev_flags) ||
+	    !_task_run(dmt))
+		goto_out;
+
+	r = 1;
+
+out:
+	if (!_udev_cookie)
+		(void) dm_udev_wait(cookie);
+
+	if (r && _switches[VERBOSE_ARG])
+		r = _display_info(dmt);
+
+	dm_task_destroy(dmt);
+
+	return r;
+}
+
+static int _create_multi_devices(const char *multi_dev_info)
+{
+	char *buffer = NULL, *dev_info, *ptr;
+	size_t buffer_size = LINE_SIZE;
+	int r = 0;
+
+	if (!(buffer = dm_malloc(buffer_size))) {
+		err("Failed to malloc line buffer.");
+		return 0;
+	}
+
+	if (!multi_dev_info) {	/* get info from stdin */
+		if (!(getline(&buffer, &buffer_size, stdin) > 0))
+			goto_out;
+	} else if (!dm_strncpy(buffer, multi_dev_info, LINE_SIZE))
+		goto_out;
+
+	dev_info = ptr = buffer;
+
+	/*
+	 * FIXME: support embedded '\;' in string data:
+	 *   s/strsep/_find_unescaped_semicolon()/
+	 */
+	while ((dev_info = strsep(&ptr, ";")) != NULL )
+		if (!_parse_device(dev_info))
+			goto_out;
+
+	r = 1;
+out:
+	memset(buffer, 0, buffer_size);
+	dm_free(buffer);
+
+	return r;
+}
+
 static int _create(CMD_ARGS)
 {
 	int r = 0;
@@ -1105,6 +1215,16 @@ static int _create(CMD_ARGS)
 	uint32_t cookie = 0;
 	uint16_t udev_flags = 0;
 
+	/* arguments are in bootformat style */
+	if (_switches[BOOTFORMAT_ARG]) {
+		if (argc > 1)
+			return 0;
+		if (argc == 1)
+			file = argv[0];
+		return _create_multi_devices(file);
+	}
+
+	/* otherwise  */
 	if (argc == 2)
 		file = argv[1];
 
@@ -5909,7 +6029,8 @@ static struct command _dmsetup_commands[] = {
 	  "\t    [-U|--uid <uid>] [-G|--gid <gid>] [-M|--mode <octal_mode>]\n"
 	  "\t    [-u|uuid <uuid>] [--addnodeonresume|--addnodeoncreate]\n"
 	  "\t    [--readahead {[+]<sectors>|auto|none}]\n"
-	  "\t    [-n|--notable|--table {<table>|<table_file>}]", 1, 2, 0, 0, _create},
+	  "\t    [-n|--notable|--table {<table>|<table_file>}]\n"
+	  "\t    [--bootformat {<multi_dev_info>|<multi_dev_info_file>}]", 0, 2, 0, 0, _create},
 	{"remove", "[--deferred] [-f|--force] [--retry] <device>...", 0, -1, 1, 0, _remove},
 	{"remove_all", "[-f|--force]", 0, 0, 0, 0, _remove_all},
 	{"suspend", "[--noflush] [--nolockfs] <device>...", 0, -1, 1, 0, _suspend},
@@ -6004,6 +6125,7 @@ static void _dmsetup_usage(FILE *out)
 	fprintf(out, "<mangling_mode> is one of 'none', 'auto' and 'hex'.\n");
 	fprintf(out, "<fields> are comma-separated.  Use 'help -c' for list.\n");
 	fprintf(out, "Table_file contents may be supplied on stdin.\n");
+	fprintf(out, "Multi_dev_info_file contents may be supplied on stdin.\n");
 	fprintf(out, "Options are: devno, devname, blkdevname.\n");
 	fprintf(out, "Tree specific options are: ascii, utf, vt100; compact, inverted, notrunc;\n"
 		     "                           blkdevname, [no]device, active, open, rw and uuid.\n");
-- 
2.9.3

Re: [linux-lvm] [PATCH 1/2] dmsetup: add support to output devices in bootformat style

[Alasdair G Kergon]

I've adapted the way this patch interacts with the various other permitted
command line options and committed it.

On Tue, May 09, 2017 at 05:48:21PM +0200, Enric Balletbo i Serra wrote:
>  dmsetup table <device...> --bootformat
 
I went for --concise in the end, as I expect it will have wider uses than just
booting.

Alasdair