'[Evms-devel] [PATCH] 2.5.3 device-mapper input'

Comments from original patch for 2.5.3: from URL http://marc.theaimsgroup.com/?l=evms-devel&m=112887246404441&w=2 '[Evms-devel] [PATCH] 2.5.3 device-mapper input' - MARC

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List:       evms-devel
Subject:    [Evms-devel] [PATCH] 2.5.3 device-mapper input
From:       
Date:       2005-10-09 15:22:10
Message-ID: 20051009142313.TJFF8556.aamta10-winn.ispmail.ntl.com () smtp ! ntlworld ! com
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Hi, Some of you may find this interesting
a patch against evms 2.5.3 to enable device-mapper devices for input into evms
This is useful for things such as layering evms on top of dmraid and dm-crypt without \
the need for loop back devices (I've tried this with dmraid and I think this should \
also work for dm-crypt) I'm posting this from a web-mail system at the moment so I \
hope the patch gets through okay

a better approach would probably be to have a seperate plugin to control the aspects \
of device-mapper raid / crypt within evms perhaps as some form of region layer but at \
the moment I'm trying to see if I can write a reiser4 plugin

only device mapper targets stated in the new config section will be picked up (no \
wildcards) devices will show up with a prefix of dm/
it's best to specify the entire disk target and let evms determine the seperate \
partitions for itself

it may even be possible to layer an evms volume on top of another evms volume \
(assuming your crazy enough to try) but I wouldn't advise it :)


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["evms-2.5.3-userdm-0.1.patch" (text/x-patch)]

[... then the patch followed ...]

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Configure | About MARC | Support MARC | Got a list to add? | Sponsored by 10East and KoreLogic Here is the patch: I assigned it USE flag "evmsdminput" in Gentoo -u diff -x'*~' -Nrup evms-2.5.4/doc/evms.conf evms-2.5.4-patched_with_dev_mapper_input/doc/evms.conf --- evms-2.5.4/doc/evms.conf 2005-11-30 06:23:58.000000000 -0800 +++ evms-2.5.4-patched_with_dev_mapper_input/doc/evms.conf 2005-12-17 15:29:48.000000000 -0800 @@ -251,3 +251,22 @@ lvm2 { device_size_prompt = yes } +# User devmapper section +# This allows us to use a device-mapper device directly as a disk +# without the need for loopback +# Be careful not to specify any targets that are created by evms +# This can be useful for any devices created via dmraid or other means + +# In order for this to work "dm*" has to be in the list of includes + +devmapper { + # This needs to be set to yes to enable + #dm_user = yes + + # List of targets to discover as disks + # These are the target names as seen with "dmsetup ls" + # only specific targets can be used + # we need to avoid evms created targets + #dm_user_targets = [ raid1_device raid0_device ] +} + diff -x'*~' -Nrup evms-2.5.4/engine/dm-targets.c evms-2.5.4-patched_with_dev_mapper_input/engine/dm-targets.c --- evms-2.5.4/engine/dm-targets.c 2005-11-07 07:46:41.000000000 -0800 +++ evms-2.5.4-patched_with_dev_mapper_input/engine/dm-targets.c 2005-12-17 15:29:48.000000000 -0800 @@ -800,28 +800,39 @@ static int mirror_build_params(dm_target * Fill in a mirror target structure based on an ASCII table string of the form: * []* [: ]{2,} * - * Currently, log_type will always be "core", num_log_params is 1, and + * Currently, log_type will always be "core", num_log_params is 1 or 2, and * log_params is chunk-size (in sectors). **/ static int mirror_translate_params(dm_target_t *target) { dm_target_mirror_t *mirror = target->data.mirror; char *params = target->params; - int i, rc; + int i, rc, num_opts; LOG_PROC_ENTRY(); - /* Skip "core 1" at the start of the string. */ - params = next_token(params); + /* Skip "core" at the start of the string. */ params = next_token(params); - rc = sscanf(params, "%u %u", &mirror->chunk_size, &mirror->num_mirrors); + /* get the number of options for core and the chunk size */ + rc = sscanf(params, "%u %u", &num_opts, &mirror->chunk_size); if (rc != 2) { rc = EINVAL; goto out; } - params = next_token(params); + + /* skip the options for core based on num_opts */ + for (i = 0; i < num_opts; i++) { + params = next_token(params); + } + + /* get the number of mirrors */ + rc = sscanf(params, "%u", &mirror->num_mirrors); + if (rc != 1) { + rc = EINVAL; + goto out; + } params = next_token(params); for (i = 0; i < mirror->num_mirrors; i++) { @@ -855,13 +866,33 @@ out: static int mirror_pretranslate_params(char *params, u_int32_t *num_devs, u_int32_t *num_groups) { - int rc; + int rc, i, num_opts = 0; + char *num_devs_point; LOG_PROC_ENTRY(); - rc = sscanf(params, "%*s %*d %*u %u", num_devs); + /* The mirror target can have more than 1 option + this affects the location of the number of member disks */ + + rc = sscanf(params, "%*s %u", &num_opts); + if (rc != 1) { + rc = EINVAL; + goto out; + } + + /* skip "core " */ + num_devs_point = next_token(params); + num_devs_point = next_token(params); + + /* skip the options for core based on num_opts */ + for (i = 0; i < num_opts; i++) { + num_devs_point = next_token(params); + } + + rc = sscanf(num_devs_point, "%u", num_devs); rc = (rc != 1) ? EINVAL : 0; +out: LOG_PROC_EXIT_INT(rc); return rc; } diff -x'*~' -Nrup evms-2.5.4/plugins/disk/localdskmgr.c evms-2.5.4-patched_with_dev_mapper_input/plugins/disk/localdskmgr.c --- evms-2.5.4/plugins/disk/localdskmgr.c 2005-10-19 08:47:24.000000000 -0700 +++ evms-2.5.4-patched_with_dev_mapper_input/plugins/disk/localdskmgr.c 2005-12-17 15:29:48.000000000 -0800 @@ -1329,13 +1329,14 @@ static int check_multipath(storage_objec rc = EngFncs->dm_get_targets(disk, &targets); if (rc) { LOG_ERROR("Error getting DM mapping for disk %s.\n", disk->name); + rc=0; goto out; } /* Reject all non-multipath devices. */ if (targets->type != DM_TARGET_MULTIPATH) { LOG_DEBUG("Disk %s is not a multipath device.\n", disk->name); - rc = EINVAL; + //rc = EINVAL; goto out; } @@ -1396,6 +1397,98 @@ static void remove_multipath_children(li } /** + * check_user_devicemapper + * + * Check if this disk is a User created DM device. + **/ +static int check_user_devicemapper(storage_object_t * disk) +{ + dm_device_list_t * dm_list, * dm_entry; + dm_target_t * targets = NULL; + local_disk_t * ld = disk->private_data; + int rc = 0, dm_user_targets_count = 0, i, dmup_len; + boolean user_dm_enable; + const char * const * dm_user_targets; + char * dm_user_prefix = "dm/"; + + LOG_ENTRY(); + + /* Get the list of active DM devices. */ + dm_list = get_dm_device_list(); + if (!dm_list) { + LOG_WARNING("Cannot get list of DM devices.\n"); + goto out; + } + + /* Search the DM list for an entry that matches this disk. */ + dm_entry = find_disk_in_dm_devices(disk, dm_list); + if (!dm_entry) { + LOG_DEBUG("Disk %s is not a DM device.\n", disk->name); + goto out; + } + + user_dm_enable = FALSE; + EngFncs->get_config_bool("devmapper.dm_user", &user_dm_enable); + + EngFncs->get_config_string_array("devmapper.dm_user_targets", + &dm_user_targets_count, &dm_user_targets); + + if (user_dm_enable == FALSE) { + LOG_DEBUG("devmapper.dm_user not enabled.\n"); + rc = EINVAL; + goto out; + } + + /* search the named targets in the config for the DM name*/ + user_dm_enable = FALSE; + for (i = 0; i < dm_user_targets_count; i++) { + if (strncmp(dm_user_targets[i], dm_entry->name, EVMS_NAME_SIZE) == 0) { + user_dm_enable = TRUE; + } + } + + if (user_dm_enable == FALSE) { + LOG_DEBUG("%s not found in devmapper.dm_user_targets.\n", dm_entry->name); + rc = EINVAL; + goto out; + } + + /* Get the DM mapping for this disk. */ + /* we can use this in the future if we need to, and it's good to check */ + strncpy(disk->name, dm_entry->name, EVMS_NAME_SIZE); + rc = EngFncs->dm_get_targets(disk, &targets); + if (rc) { + LOG_ERROR("Error getting DM mapping for disk %s.\n", disk->name); + goto out; + } + + /* Copy the DM name to this disk. */ + dmup_len = strlen(dm_user_prefix); + LOG_DEBUG("Changing disk name from %s to %s%s.\n", + disk->name, dm_user_prefix ,dm_entry->name); + + strncpy(disk->name, dm_user_prefix, dmup_len); + strncpy((disk->name)+dmup_len, dm_entry->name, EVMS_NAME_SIZE-dmup_len); + + /* Reject all multipath devices that + * were created by other EVMS plugins. + */ + rc = check_multipath_name(disk); + if (rc) { + LOG_DEBUG("Multipath disk %s belongs to another EVMS plugin.\n", + disk->name); + goto out; + } + + ld->flags |= LD_FLAG_USERDM; + +out: + /*EngFncs->dm_deallocate_targets(targets); */ + LOG_EXIT_INT(rc); + return rc; +} + +/** * get_geometry * * Use the HDIO_GETGEO_BIG or HDIO_GETGEO ioctl to get the disk's geometry. @@ -1478,6 +1571,7 @@ static int get_fake_geometry(storage_obj if (disk->dev_major == LOOP_MAJOR || disk->dev_major == NBD_MAJOR || disk->dev_major == DRBD_MAJOR || + ld->flags & LD_FLAG_USERDM || ld->flags & LD_FLAG_MULTIPATH) { LOG_DEBUG("Creating fake geometry for disk %s.\n", disk->name); disk->geometry.heads = 255; @@ -1745,6 +1839,13 @@ static int LD_discover(list_anchor_t inp /* Get the disk's hard-sector-size. */ get_hardsector_size(&working_disk); + /* Check for User created DM devices. */ + rc = check_user_devicemapper(&working_disk); + if (rc) { + close_dev(&working_disk); + continue; + } + /* Get the disk's geometry. */ rc = get_geometry(&working_disk); if (rc) { diff -x'*~' -Nrup evms-2.5.4/plugins/disk/localdskmgr.h evms-2.5.4-patched_with_dev_mapper_input/plugins/disk/localdskmgr.h --- evms-2.5.4/plugins/disk/localdskmgr.h 2005-05-17 13:38:55.000000000 -0700 +++ evms-2.5.4-patched_with_dev_mapper_input/plugins/disk/localdskmgr.h 2005-12-17 15:29:48.000000000 -0800 @@ -80,6 +80,7 @@ typedef struct local_disk { #define LD_FLAG_MULTIPATH (1 << 0) #define LD_FLAG_IDE (1 << 1) #define LD_FLAG_SCSI (1 << 2) +#define LD_FLAG_USERDM (1 << 3) extern engine_functions_t *EngFncs; extern plugin_record_t *my_plugin_record;