From patchwork Tue Jun 8 03:25:24 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Drewry X-Patchwork-Id: 104861 X-Patchwork-Delegate: agk@redhat.com Received: from mx02.colomx.prod.int.phx2.redhat.com (mx4-phx2.redhat.com [209.132.183.25]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o583TR8E010617 for ; Tue, 8 Jun 2010 03:30:03 GMT Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by mx02.colomx.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o583RKBc014659; Mon, 7 Jun 2010 23:27:20 -0400 Received: from int-mx08.intmail.prod.int.phx2.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o583QHKp021655 for ; Mon, 7 Jun 2010 23:26:17 -0400 Received: from mx1.redhat.com (ext-mx07.extmail.prod.ext.phx2.redhat.com [10.5.110.11]) by int-mx08.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o583QCdY011612; Mon, 7 Jun 2010 23:26:12 -0400 Received: from mail-iw0-f174.google.com (mail-iw0-f174.google.com [209.85.214.174]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o583Q1VB016251; Mon, 7 Jun 2010 23:26:01 -0400 Received: by iwn37 with SMTP id 37so5217128iwn.33 for ; Mon, 07 Jun 2010 20:26:01 -0700 (PDT) Received: by 10.231.130.142 with SMTP id t14mr5538255ibs.155.1275967560729; Mon, 07 Jun 2010 20:26:00 -0700 (PDT) Received: from localhost.localdomain (208-191-153-102.lightspeed.austtx.sbcglobal.net [208.191.153.102]) by mx.google.com with ESMTPS id d9sm23685924ibl.10.2010.06.07.20.25.57 (version=TLSv1/SSLv3 cipher=RC4-MD5); Mon, 07 Jun 2010 20:26:00 -0700 (PDT) From: Will Drewry To: dm-devel@redhat.com Date: Mon, 7 Jun 2010 22:25:24 -0500 Message-Id: <1275967524-24166-3-git-send-email-wad@chromium.org> In-Reply-To: <1274294304-30606-1-git-send-email-wad@chromium.org> References: <1274294304-30606-1-git-send-email-wad@chromium.org> X-RedHat-Spam-Score: -0.001 (SPF_PASS) X-Scanned-By: MIMEDefang 2.67 on 10.5.11.21 X-Scanned-By: MIMEDefang 2.67 on 10.5.110.11 X-loop: dm-devel@redhat.com Cc: Michal Marek , Len Brown , Will Drewry , Mike Snitzer , Kiyoshi Ueda , Nikanth Karthikesan , Greg Kroah-Hartman , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, Tejun Heo , Randy Dunlap , Mikulas Patocka , Vegard Nossum , "Jun'ichi Nomura" , Ingo Molnar , Jan Blunck , Sam Ravnborg , Alasdair G Kergon Subject: [dm-devel] [PATCH v4 3/3] init: add support to directly boot to a mapped device X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk Reply-To: device-mapper development List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Tue, 08 Jun 2010 03:30:03 +0000 (UTC) diff --git a/Documentation/device-mapper/boot.txt b/Documentation/device-mapper/boot.txt new file mode 100644 index 0000000..76ea6ac --- /dev/null +++ b/Documentation/device-mapper/boot.txt @@ -0,0 +1,42 @@ +Boot time creation of mapped devices +=================================== + +It is possible to configure a device mapper device to act as the root +device for your system in two ways. + +The first is to build an initial ramdisk which boots to a minimal +userspace which configures the device, then pivot_root(8) in to it. + +For simple device mapper configurations, it is possible to boot directly +using the following kernel command line: + +dm=" ,table line 1,...,table line n" + +name = the name to associate with the device + after boot, udev, if used, will use that name to label + the device node. +uuid = may be 'none' or the UUID desired for the device. +ro = may be 'ro' or 'rw'. If 'ro', the device and device table will be + marked read-only. + +Each table line may be as normal when using the dmsetup tool except for +two variations: +1. Any use of commas will be interpreted as a newline +2. Quotation marks cannot be escaped and cannot be used without + terminating the dm= argument. + +Unless renamed by udev, the device node created will be dm-0 as the +first minor number for the device-mapper is used during early creation. + +Example +======= + +- Booting to a linear array made up of user-mode linux block devices: + + dm="lroot none 0, 0 4096 linear 98:16 0, 4096 4096 linear 98:32 0" \ + root=/dev/dm-0 + +Will boot to a rw dm-linear target of 8192 sectors split across two +block devices identified by their major:minor numbers. After boot, udev +will rename this target to /dev/mapper/lroot (depending on the rules). +No uuid was assigned. diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 1808f11..01d85c9 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -43,6 +43,7 @@ parameter is applicable: AVR32 AVR32 architecture is enabled. AX25 Appropriate AX.25 support is enabled. BLACKFIN Blackfin architecture is enabled. + DM Device mapper support is enabled. DRM Direct Rendering Management support is enabled. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled EFI EFI Partitioning (GPT) is enabled @@ -655,6 +656,9 @@ and is between 256 and 4096 characters. It is defined in the file Disable PIN 1 of APIC timer Can be useful to work around chipset bugs. + dm= [DM] Allows early creation of a device-mapper device. + See Documentation/device-mapper/boot.txt. + dmasound= [HW,OSS] Sound subsystem buffers dma_debug=off If the kernel is compiled with DMA_API_DEBUG support, diff --git a/init/Makefile b/init/Makefile index 0bf677a..1677baa 100644 --- a/init/Makefile +++ b/init/Makefile @@ -14,6 +14,7 @@ mounts-y := do_mounts.o mounts-$(CONFIG_BLK_DEV_RAM) += do_mounts_rd.o mounts-$(CONFIG_BLK_DEV_INITRD) += do_mounts_initrd.o mounts-$(CONFIG_BLK_DEV_MD) += do_mounts_md.o +mounts-$(CONFIG_BLK_DEV_DM) += do_mounts_dm.o # dependencies on generated files need to be listed explicitly $(obj)/version.o: include/generated/compile.h diff --git a/init/do_mounts.c b/init/do_mounts.c index 02e3ca4..0848a5b 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -383,6 +383,7 @@ void __init prepare_namespace(void) wait_for_device_probe(); md_run_setup(); + dm_run_setup(); if (saved_root_name[0]) { root_device_name = saved_root_name; diff --git a/init/do_mounts.h b/init/do_mounts.h index f5b978a..09d2286 100644 --- a/init/do_mounts.h +++ b/init/do_mounts.h @@ -74,3 +74,13 @@ void md_run_setup(void); static inline void md_run_setup(void) {} #endif + +#ifdef CONFIG_BLK_DEV_DM + +void dm_run_setup(void); + +#else + +static inline void dm_run_setup(void) {} + +#endif diff --git a/init/do_mounts_dm.c b/init/do_mounts_dm.c new file mode 100644 index 0000000..b342f8f --- /dev/null +++ b/init/do_mounts_dm.c @@ -0,0 +1,414 @@ +/* do_mounts_dm.c + * Copyright (C) 2010 The Chromium OS Authors + * All Rights Reserved. + * Based on do_mounts_md.c + * + * This file is released under the GPL. + */ +#include +#include +#include + +#include "do_mounts.h" + +#define DM_MAX_NAME 32 +#define DM_MAX_UUID 129 +#define DM_NO_UUID "none" + +#define DM_MSG_PREFIX "init" + +/* Separators used for parsing the dm= argument. */ +#define DM_FIELD_SEP ' ' +#define DM_LINE_SEP ',' + +/* + * When the device-mapper and any targets are compiled into the kernel + * (not a module), one target may be created and used as the root device at + * boot time with the parameters given with the boot line dm=... + * The code for that is here. + */ + +struct dm_setup_target { + sector_t begin; + sector_t length; + char *type; + char *params; + /* simple singly linked list */ + struct dm_setup_target *next; +}; + +static struct { + int minor; + int ro; + char name[DM_MAX_NAME]; + char uuid[DM_MAX_UUID]; + char *targets; + struct dm_setup_target *target; + int target_count; +} dm_setup_args __initdata; + +static __initdata int dm_early_setup; + +static size_t __init get_dm_option(char *str, char **next, char sep) +{ + size_t len = 0; + char *endp = NULL; + + if (!str) + return 0; + + endp = strchr(str, sep); + if (!endp) { /* act like strchrnul */ + len = strlen(str); + endp = str + len; + } else { + len = endp - str; + } + + if (endp == str) + return 0; + + if (!next) + return len; + + if (*endp == 0) { + /* Don't advance past the nul. */ + *next = endp; + } else { + *next = endp + 1; + } + return len; +} + +static int __init dm_setup_args_init(void) +{ + dm_setup_args.minor = 0; + dm_setup_args.ro = 0; + dm_setup_args.target = NULL; + dm_setup_args.target_count = 0; + return 0; +} + +static int __init dm_setup_cleanup(void) +{ + struct dm_setup_target *target = dm_setup_args.target; + struct dm_setup_target *old_target = NULL; + while (target) { + kfree(target->type); + kfree(target->params); + old_target = target; + target = target->next; + kfree(old_target); + dm_setup_args.target_count--; + } + BUG_ON(dm_setup_args.target_count); + return 0; +} + +static char * __init dm_setup_parse_device_args(char *str) +{ + char *next = NULL; + size_t len = 0; + + /* Grab the logical name of the device to be exported to udev */ + len = get_dm_option(str, &next, DM_FIELD_SEP); + if (!len) { + DMERR("failed to parse device name"); + goto parse_fail; + } + len = min(len + 1, sizeof(dm_setup_args.name)); + strlcpy(dm_setup_args.name, str, len); /* includes nul */ + str = skip_spaces(next); + + /* Grab the UUID value or "none" */ + len = get_dm_option(str, &next, DM_FIELD_SEP); + if (!len) { + DMERR("failed to parse device uuid"); + goto parse_fail; + } + len = min(len + 1, sizeof(dm_setup_args.uuid)); + strlcpy(dm_setup_args.uuid, str, len); + str = skip_spaces(next); + + /* Determine if the table/device will be read onyl or read-write */ + if (!strncmp("ro,", str, 3)) { + dm_setup_args.ro = 1; + } else if (!strncmp("rw,", str, 3)) { + dm_setup_args.ro = 0; + } else { + DMERR("failed to parse table mode"); + goto parse_fail; + } + str = skip_spaces(str + 3); + + return str; + +parse_fail: + return NULL; +} + +static void __init dm_substitute_devices(char *str, size_t str_len) +{ + char *candidate = str; + char *candidate_end = str; + char old_char; + size_t len = 0; + dev_t dev; + + if (str_len < 3) + return; + + while (str && *str) { + candidate = strchr(str, '/'); + if (!candidate) + break; + + /* Avoid embedded slashes */ + if (candidate != str && *(candidate - 1) != DM_FIELD_SEP) { + str = strchr(candidate, DM_FIELD_SEP); + continue; + } + + len = get_dm_option(candidate, &candidate_end, DM_FIELD_SEP); + str = skip_spaces(candidate_end); + if (len < 3) /* maj:mix min */ + continue; + + /* Temporarily terminate with a nul */ + candidate_end--; + old_char = *candidate_end; + *candidate_end = '\0'; + + DMDEBUG("converting candidate device '%s' to dev_t", candidate); + /* Use the boot-time specific device naming */ + dev = name_to_dev_t(candidate); + *candidate_end = old_char; + + DMDEBUG(" -> %u", dev); + /* No suitable replacement found */ + if (!dev) + continue; + + /* Rewrite the /dev/path as a major:minor */ + len = snprintf(candidate, len, "%u:%u", MAJOR(dev), MINOR(dev)); + if (!len) { + DMERR("error substituting device major/minor."); + break; + } + candidate += len; + /* Pad out with spaces (fixing our nul) */ + while (candidate < candidate_end) + *(candidate++) = DM_FIELD_SEP; + } +} + +static int __init dm_setup_parse_targets(char *str) +{ + char *next = NULL; + size_t len = 0; + struct dm_setup_target **target = NULL; + + /* Targets are defined as per the table format but with a + * comma as a newline separator. + */ + target = &dm_setup_args.target; + while (str && *str) { + *target = kzalloc(sizeof(struct dm_setup_target), GFP_KERNEL); + if (!*target) { + DMERR("failed to allocate memory for target %d", + dm_setup_args.target_count); + goto parse_fail; + } + dm_setup_args.target_count++; + + (*target)->begin = simple_strtoull(str, &next, 10); + if (!next || *next != DM_FIELD_SEP) { + DMERR("failed to parse starting sector for target %d", + dm_setup_args.target_count - 1); + goto parse_fail; + } + str = skip_spaces(next + 1); + + (*target)->length = simple_strtoull(str, &next, 10); + if (!next || *next != DM_FIELD_SEP) { + DMERR("failed to parse length for target %d", + dm_setup_args.target_count - 1); + goto parse_fail; + } + str = skip_spaces(next + 1); + + len = get_dm_option(str, &next, DM_FIELD_SEP); + if (!len || + !((*target)->type = kstrndup(str, len, GFP_KERNEL))) { + DMERR("failed to parse type for target %d", + dm_setup_args.target_count - 1); + goto parse_fail; + } + str = skip_spaces(next); + + len = get_dm_option(str, &next, DM_LINE_SEP); + if (!len || + !((*target)->params = kstrndup(str, len, GFP_KERNEL))) { + DMERR("failed to parse params for target %d", + dm_setup_args.target_count - 1); + goto parse_fail; + } + str = skip_spaces(next); + + /* Before moving on, walk through the copied target and + * attempt to replace all /dev/xxx with the major:minor number. + * It may not be possible to resolve them traditionally at + * boot-time. + */ + dm_substitute_devices((*target)->params, len); + + target = &((*target)->next); + } + DMDEBUG("parsed %d targets", dm_setup_args.target_count); + + return 0; + +parse_fail: + return 1; +} + +/* + * Parse the command-line parameters given our kernel, but do not + * actually try to invoke the DM device now; that is handled by + * dm_setup_drive after the low-level disk drivers have initialised. + * dm format is as follows: + * dm="name uuid fmode,[table line 1],[table line 2],..." + * May be used with root=/dev/dm-0 as it always uses the first dm minor. + */ + +static int __init dm_setup(char *str) +{ + dm_setup_args_init(); + + str = dm_setup_parse_device_args(str); + if (!str) { + DMDEBUG("str is NULL"); + goto parse_fail; + } + + /* Target parsing is delayed until we have dynamic memory */ + dm_setup_args.targets = str; + + printk(KERN_INFO "dm: will configure '%s' on dm-%d\n", + dm_setup_args.name, dm_setup_args.minor); + + dm_early_setup = 1; + return 1; + +parse_fail: + printk(KERN_WARNING "dm: Invalid arguments supplied to dm=.\n"); + return 0; +} + + +static void __init dm_setup_drive(void) +{ + struct mapped_device *md = NULL; + struct dm_table *table = NULL; + struct dm_setup_target *target; + char *uuid = dm_setup_args.uuid; + fmode_t fmode = FMODE_READ; + + /* Finish parsing the targets. */ + if (dm_setup_parse_targets(dm_setup_args.targets)) + goto parse_fail; + + if (dm_create(dm_setup_args.minor, &md)) { + DMDEBUG("failed to create the device"); + goto dm_create_fail; + } + DMDEBUG("created device '%s'", dm_device_name(md)); + + /* In addition to flagging the table below, the disk must be + * set explicitly ro/rw. + */ + set_disk_ro(dm_disk(md), dm_setup_args.ro); + + if (!dm_setup_args.ro) + fmode |= FMODE_WRITE; + if (dm_table_create(&table, fmode, dm_setup_args.target_count, md)) { + DMDEBUG("failed to create the table"); + goto dm_table_create_fail; + } + + target = dm_setup_args.target; + while (target) { + DMINFO("adding target '%llu %llu %s %s'", + (unsigned long long) target->begin, + (unsigned long long) target->length, target->type, + target->params); + if (dm_table_add_target(table, target->type, target->begin, + target->length, target->params)) { + DMDEBUG("failed to add the target to the table"); + goto add_target_fail; + } + target = target->next; + } + + if (dm_table_complete(table)) { + DMDEBUG("failed to complete the table"); + goto table_complete_fail; + } + + /* Suspend the device so that we can bind it to the table. */ + if (dm_suspend(md, 0)) { + DMDEBUG("failed to suspend the device pre-bind"); + goto suspend_fail; + } + + /* Bind the table to the device. This is the only way to associate + * md->map with the table and set the disk capacity directly. + */ + if (dm_swap_table(md, table)) { /* should return NULL. */ + DMDEBUG("failed to bind the device to the table"); + goto table_bind_fail; + } + + /* Finally, resume and the device should be ready. */ + if (dm_resume(md)) { + DMDEBUG("failed to resume the device"); + goto resume_fail; + } + + /* Export the dm device via the ioctl interface */ + if (!strcmp(DM_NO_UUID, dm_setup_args.uuid)) + uuid = NULL; + if (dm_ioctl_export(md, dm_setup_args.name, uuid)) { + DMDEBUG("failed to export device with given name and uuid"); + goto export_fail; + } + printk(KERN_INFO "dm: dm-%d is ready\n", dm_setup_args.minor); + + dm_setup_cleanup(); + return; + +export_fail: +resume_fail: +table_bind_fail: +suspend_fail: +table_complete_fail: +add_target_fail: + dm_table_put(table); +dm_table_create_fail: + dm_put(md); +dm_create_fail: + dm_setup_cleanup(); +parse_fail: + printk(KERN_WARNING "dm: starting dm-%d (%s) failed\n", + dm_setup_args.minor, dm_setup_args.name); +} + +__setup("dm=", dm_setup); + +void __init dm_run_setup(void) +{ + if (!dm_early_setup) + return; + printk(KERN_INFO "dm: attempting early device configuration.\n"); + dm_setup_drive(); +}