diff options
-rw-r--r-- | Documentation/device-mapper/dm-raid.txt | 44 | ||||
-rw-r--r-- | drivers/md/dm-raid.c | 123 |
2 files changed, 140 insertions, 27 deletions
diff --git a/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt index 56fb62b09fc5..b428556197c9 100644 --- a/Documentation/device-mapper/dm-raid.txt +++ b/Documentation/device-mapper/dm-raid.txt @@ -30,6 +30,7 @@ The target is named "raid" and it accepts the following parameters: raid10 Various RAID10 inspired algorithms chosen by additional params - RAID10: Striped Mirrors (aka 'Striping on top of mirrors') - RAID1E: Integrated Adjacent Stripe Mirroring + - RAID1E: Integrated Offset Stripe Mirroring - and other similar RAID10 variants Reference: Chapter 4 of @@ -64,15 +65,15 @@ The target is named "raid" and it accepts the following parameters: synchronisation state for each region. [raid10_copies <# copies>] - [raid10_format near] + [raid10_format <near|far|offset>] These two options are used to alter the default layout of a RAID10 configuration. The number of copies is can be - specified, but the default is 2. There are other variations - to how the copies are laid down - the default and only current - option is "near". Near copies are what most people think of - with respect to mirroring. If these options are left - unspecified, or 'raid10_copies 2' and/or 'raid10_format near' - are given, then the layouts for 2, 3 and 4 devices are: + specified, but the default is 2. There are also three + variations to how the copies are laid down - the default + is "near". Near copies are what most people think of with + respect to mirroring. If these options are left unspecified, + or 'raid10_copies 2' and/or 'raid10_format near' are given, + then the layouts for 2, 3 and 4 devices are: 2 drives 3 drives 4 drives -------- ---------- -------------- A1 A1 A1 A1 A2 A1 A1 A2 A2 @@ -85,6 +86,33 @@ The target is named "raid" and it accepts the following parameters: 3-device layout is what might be called a 'RAID1E - Integrated Adjacent Stripe Mirroring'. + If 'raid10_copies 2' and 'raid10_format far', then the layouts + for 2, 3 and 4 devices are: + 2 drives 3 drives 4 drives + -------- -------------- -------------------- + A1 A2 A1 A2 A3 A1 A2 A3 A4 + A3 A4 A4 A5 A6 A5 A6 A7 A8 + A5 A6 A7 A8 A9 A9 A10 A11 A12 + .. .. .. .. .. .. .. .. .. + A2 A1 A3 A1 A2 A2 A1 A4 A3 + A4 A3 A6 A4 A5 A6 A5 A8 A7 + A6 A5 A9 A7 A8 A10 A9 A12 A11 + .. .. .. .. .. .. .. .. .. + + If 'raid10_copies 2' and 'raid10_format offset', then the + layouts for 2, 3 and 4 devices are: + 2 drives 3 drives 4 drives + -------- ------------ ----------------- + A1 A2 A1 A2 A3 A1 A2 A3 A4 + A2 A1 A3 A1 A2 A2 A1 A4 A3 + A3 A4 A4 A5 A6 A5 A6 A7 A8 + A4 A3 A6 A4 A5 A6 A5 A8 A7 + A5 A6 A7 A8 A9 A9 A10 A11 A12 + A6 A5 A9 A7 A8 A10 A9 A12 A11 + .. .. .. .. .. .. .. .. .. + Here we see layouts closely akin to 'RAID1E - Integrated + Offset Stripe Mirroring'. + <#raid_devs>: The number of devices composing the array. Each device consists of two entries. The first is the device containing the metadata (if any); the second is the one containing the @@ -142,3 +170,5 @@ Version History 1.3.0 Added support for RAID 10 1.3.1 Allow device replacement/rebuild for RAID 10 1.3.2 Fix/improve redundancy checking for RAID10 +1.4.0 Non-functional change. Removes arg from mapping function. +1.4.1 Add RAID10 "far" and "offset" algorithm support. diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 9e58dbd8d8cb..22fd55993723 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -91,15 +91,44 @@ static struct raid_type { {"raid6_nc", "RAID6 (N continue)", 2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE} }; +static char *raid10_md_layout_to_format(int layout) +{ + /* + * Bit 16 and 17 stand for "offset" and "use_far_sets" + * Refer to MD's raid10.c for details + */ + if ((layout & 0x10000) && (layout & 0x20000)) + return "offset"; + + if ((layout & 0xFF) > 1) + return "near"; + + return "far"; +} + static unsigned raid10_md_layout_to_copies(int layout) { - return layout & 0xFF; + if ((layout & 0xFF) > 1) + return layout & 0xFF; + return (layout >> 8) & 0xFF; } static int raid10_format_to_md_layout(char *format, unsigned copies) { - /* 1 "far" copy, and 'copies' "near" copies */ - return (1 << 8) | (copies & 0xFF); + unsigned n = 1, f = 1; + + if (!strcmp("near", format)) + n = copies; + else + f = copies; + + if (!strcmp("offset", format)) + return 0x30000 | (f << 8) | n; + + if (!strcmp("far", format)) + return 0x20000 | (f << 8) | n; + + return (f << 8) | n; } static struct raid_type *get_raid_type(char *name) @@ -352,6 +381,7 @@ static int validate_raid_redundancy(struct raid_set *rs) { unsigned i, rebuild_cnt = 0; unsigned rebuilds_per_group, copies, d; + unsigned group_size, last_group_start; for (i = 0; i < rs->md.raid_disks; i++) if (!test_bit(In_sync, &rs->dev[i].rdev.flags) || @@ -379,9 +409,6 @@ static int validate_raid_redundancy(struct raid_set *rs) * as long as the failed devices occur in different mirror * groups (i.e. different stripes). * - * Right now, we only allow for "near" copies. When other - * formats are added, we will have to check those too. - * * When checking "near" format, make sure no adjacent devices * have failed beyond what can be handled. In addition to the * simple case where the number of devices is a multiple of the @@ -391,14 +418,41 @@ static int validate_raid_redundancy(struct raid_set *rs) * A A B B C * C D D E E */ - for (i = 0; i < rs->md.raid_disks * copies; i++) { - if (!(i % copies)) + if (!strcmp("near", raid10_md_layout_to_format(rs->md.layout))) { + for (i = 0; i < rs->md.raid_disks * copies; i++) { + if (!(i % copies)) + rebuilds_per_group = 0; + d = i % rs->md.raid_disks; + if ((!rs->dev[d].rdev.sb_page || + !test_bit(In_sync, &rs->dev[d].rdev.flags)) && + (++rebuilds_per_group >= copies)) + goto too_many; + } + break; + } + + /* + * When checking "far" and "offset" formats, we need to ensure + * that the device that holds its copy is not also dead or + * being rebuilt. (Note that "far" and "offset" formats only + * support two copies right now. These formats also only ever + * use the 'use_far_sets' variant.) + * + * This check is somewhat complicated by the need to account + * for arrays that are not a multiple of (far) copies. This + * results in the need to treat the last (potentially larger) + * set differently. + */ + group_size = (rs->md.raid_disks / copies); + last_group_start = (rs->md.raid_disks / group_size) - 1; + last_group_start *= group_size; + for (i = 0; i < rs->md.raid_disks; i++) { + if (!(i % copies) && !(i > last_group_start)) rebuilds_per_group = 0; - d = i % rs->md.raid_disks; - if ((!rs->dev[d].rdev.sb_page || - !test_bit(In_sync, &rs->dev[d].rdev.flags)) && + if ((!rs->dev[i].rdev.sb_page || + !test_bit(In_sync, &rs->dev[i].rdev.flags)) && (++rebuilds_per_group >= copies)) - goto too_many; + goto too_many; } break; default: @@ -433,7 +487,7 @@ too_many: * * RAID10-only options: * [raid10_copies <# copies>] Number of copies. (Default: 2) - * [raid10_format <near>] Layout algorithm. (Default: near) + * [raid10_format <near|far|offset>] Layout algorithm. (Default: near) */ static int parse_raid_params(struct raid_set *rs, char **argv, unsigned num_raid_params) @@ -520,7 +574,9 @@ static int parse_raid_params(struct raid_set *rs, char **argv, rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type"; return -EINVAL; } - if (strcmp("near", argv[i])) { + if (strcmp("near", argv[i]) && + strcmp("far", argv[i]) && + strcmp("offset", argv[i])) { rs->ti->error = "Invalid 'raid10_format' value given"; return -EINVAL; } @@ -644,6 +700,15 @@ static int parse_raid_params(struct raid_set *rs, char **argv, return -EINVAL; } + /* + * If the format is not "near", we only support + * two copies at the moment. + */ + if (strcmp("near", raid10_format) && (raid10_copies > 2)) { + rs->ti->error = "Too many copies for given RAID10 format."; + return -EINVAL; + } + /* (Len * #mirrors) / #devices */ sectors_per_dev = rs->ti->len * raid10_copies; sector_div(sectors_per_dev, rs->md.raid_disks); @@ -854,17 +919,30 @@ static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev) /* * Reshaping is not currently allowed */ - if ((le32_to_cpu(sb->level) != mddev->level) || - (le32_to_cpu(sb->layout) != mddev->layout) || - (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors)) { - DMERR("Reshaping arrays not yet supported."); + if (le32_to_cpu(sb->level) != mddev->level) { + DMERR("Reshaping arrays not yet supported. (RAID level change)"); + return -EINVAL; + } + if (le32_to_cpu(sb->layout) != mddev->layout) { + DMERR("Reshaping arrays not yet supported. (RAID layout change)"); + DMERR(" 0x%X vs 0x%X", le32_to_cpu(sb->layout), mddev->layout); + DMERR(" Old layout: %s w/ %d copies", + raid10_md_layout_to_format(le32_to_cpu(sb->layout)), + raid10_md_layout_to_copies(le32_to_cpu(sb->layout))); + DMERR(" New layout: %s w/ %d copies", + raid10_md_layout_to_format(mddev->layout), + raid10_md_layout_to_copies(mddev->layout)); + return -EINVAL; + } + if (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors) { + DMERR("Reshaping arrays not yet supported. (stripe sectors change)"); return -EINVAL; } /* We can only change the number of devices in RAID1 right now */ if ((rs->raid_type->level != 1) && (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) { - DMERR("Reshaping arrays not yet supported."); + DMERR("Reshaping arrays not yet supported. (device count change)"); return -EINVAL; } @@ -1329,7 +1407,8 @@ static int raid_status(struct dm_target *ti, status_type_t type, raid10_md_layout_to_copies(rs->md.layout)); if (rs->print_flags & DMPF_RAID10_FORMAT) - DMEMIT(" raid10_format near"); + DMEMIT(" raid10_format %s", + raid10_md_layout_to_format(rs->md.layout)); DMEMIT(" %d", rs->md.raid_disks); for (i = 0; i < rs->md.raid_disks; i++) { @@ -1420,6 +1499,10 @@ static struct target_type raid_target = { static int __init dm_raid_init(void) { + DMINFO("Loading target version %u.%u.%u", + raid_target.version[0], + raid_target.version[1], + raid_target.version[2]); return dm_register_target(&raid_target); } |