From ecbfb9f118bce49f571675929160e4ecef91cc8a Mon Sep 17 00:00:00 2001 From: Heinz Mauelshagen Date: Thu, 19 May 2016 18:49:33 +0200 Subject: [PATCH] dm raid: add raid level takeover support Add raid level takeover support allowing arbitrary takeovers between raid levels supported by md personalities (i.e. raid0, raid1/10 and raid4/5/6): - add rs_config_{backup|restore} function to allow for temporary storing ctr requested layout changes and restore them for takeover conersion decision after the superblocks got loaded and analyzed - add members to store layout to 'struct raid_set' (not mandatory for takeover but needed for reshape in later patch) - add rebuild_disks bitfield to 'struct raid_set' and set bits in ctr to use in setting up takeover (base to address a 'rebuild' related raid_status() table line bug and needed as well for reshape in future patch) - add runtime flags and respective manipulation functions to be able to control e.g. wrting of superlocks to the preresume function on takeover and (later) reshape - add functions to detect takeover, check it's valid (mandatory here to avoid failing on md_run()), setup for it and use in the ctr; those will be likely moved out once reshaping gets added to simplify the ctr - start raid set readonly in ctr and switch to readwrite, optionally updating superblocks, in preresume in order to allow suspend to quiesce any active table before (which involves superblock updates); this ensures the proper sequence of writing the current and any new takeover(/reshape) metadata Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer --- drivers/md/dm-raid.c | 455 ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 426 insertions(+), 29 deletions(-) diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 28420337f880..89b677c7cfe6 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -98,6 +98,13 @@ struct raid_dev { #define ALL_CTR_FLAGS (CTR_FLAG_OPTIONS_NO_ARGS | \ CTR_FLAG_OPTIONS_ONE_ARG) +/* + * All flags which cause a recovery unfreeze once they got stored in the raid metadata + */ +#define ALL_FREEZE_FLAGS (ALL_CTR_FLAGS & ~(CTR_FLAG_REGION_SIZE | CTR_FLAGS_ANY_SYNC | \ + CTR_FLAG_RAID10_FORMAT | CTR_FLAG_RAID10_COPIES | \ + CTR_FLAG_RAID10_USE_NEAR_SETS)) + /* Invalid options definitions per raid level... */ /* "raid0" does not accept any options */ @@ -129,14 +136,39 @@ struct raid_dev { #define RAID6_INVALID_FLAGS (CTR_FLAG_NOSYNC | RAID45_INVALID_FLAGS) /* ...invalid options definitions per raid level */ +/* + * Flags for rs->runtime_flags field + * (RT_FLAG prefix meaning "runtime flag") + * + * These are all internal and used to define runtime state, + * e.g. to prevent another resume from preresume processing + * the raid set all over again. + */ +#define RT_FLAG_RS_PRERESUMED 0x1 +#define RT_FLAG_RS_RESUMED 0x2 +#define RT_FLAG_RS_BITMAP_LOADED 0x4 +#define RT_FLAG_UPDATE_SBS 0x8 + /* Array elements of 64 bit needed for rebuild/write_mostly bits */ #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8) +/* + * raid set level, layout and chunk sectors backup/restore + */ +struct rs_layout { + int new_level; + int new_layout; + int new_chunk_sectors; +}; + struct raid_set { struct dm_target *ti; uint32_t bitmap_loaded; uint32_t ctr_flags; + uint32_t runtime_flags; + + uint64_t rebuild_disks[DISKS_ARRAY_ELEMS]; int raid_disks; int delta_disks; @@ -146,10 +178,41 @@ struct raid_set { struct mddev md; struct raid_type *raid_type; struct dm_target_callbacks callbacks; + struct rs_layout rs_layout; struct raid_dev dev[0]; }; +/* Backup/restore raid set configuration helpers */ +static void _rs_config_backup(struct raid_set *rs, struct rs_layout *l) +{ + struct mddev *mddev = &rs->md; + + l->new_level = mddev->new_level; + l->new_layout = mddev->new_layout; + l->new_chunk_sectors = mddev->new_chunk_sectors; +} + +static void rs_config_backup(struct raid_set *rs) +{ + return _rs_config_backup(rs, &rs->rs_layout); +} + +static void _rs_config_restore(struct raid_set *rs, struct rs_layout *l) +{ + struct mddev *mddev = &rs->md; + + mddev->new_level = l->new_level; + mddev->new_layout = l->new_layout; + mddev->new_chunk_sectors = l->new_chunk_sectors; +} + +static void rs_config_restore(struct raid_set *rs) +{ + return _rs_config_restore(rs, &rs->rs_layout); +} +/* END: backup/restore raid set configuration helpers */ + /* raid10 algorithms (i.e. formats) */ #define ALGORITHM_RAID10_DEFAULT 0 #define ALGORITHM_RAID10_NEAR 1 @@ -201,6 +264,13 @@ static void _set_flag(uint32_t flag, uint32_t *flags) *flags |= flag; } +/* Clear single @flag in @flags */ +static void _clear_flag(uint32_t flag, uint32_t *flags) +{ + WARN_ON_ONCE(hweight32(flag) != 1); + *flags &= ~flag; +} + /* Test single @flag in @flags */ static bool _test_flag(uint32_t flag, uint32_t flags) { @@ -229,6 +299,17 @@ static bool _test_and_set_flag(uint32_t flag, uint32_t *flags) _set_flag(flag, flags); return false; } + +/* Return true if single @flag is set in @*flags and clear it, else return false */ +static bool _test_and_clear_flag(uint32_t flag, uint32_t *flags) +{ + if (_test_flag(flag, *flags)) { + _clear_flag(flag, flags); + return true; + } + + return false; +} /* ...ctr and runtime flag bit manipulation */ /* All table line arguments are defined here */ @@ -576,7 +657,7 @@ static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *ra rs->md.layout = raid_type->algorithm; rs->md.new_layout = rs->md.layout; rs->md.delta_disks = 0; - rs->md.recovery_cp = 0; + rs->md.recovery_cp = rs_is_raid0(rs) ? MaxSector : 0; for (i = 0; i < raid_devs; i++) md_rdev_init(&rs->dev[i].rdev); @@ -1007,9 +1088,12 @@ static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as, * indexes of replaced devices and to set up additional * devices on raid level takeover. */ - if (!_in_range(value, 0, rs->md.raid_disks - 1)) + if (!_in_range(value, 0, rs->raid_disks - 1)) return ti_error_einval(rs->ti, "Invalid rebuild index given"); + if (test_and_set_bit(value, (void *) rs->rebuild_disks)) + return ti_error_einval(rs->ti, "rebuild for this index already given"); + rd = rs->dev + value; clear_bit(In_sync, &rd->rdev.flags); clear_bit(Faulty, &rd->rdev.flags); @@ -1175,8 +1259,166 @@ static int raid_is_congested(struct dm_target_callbacks *cb, int bits) return mddev_congested(&rs->md, bits); } +/* + * Make sure a valid takover (level switch) is being requested on @rs + * + * Conversions of raid sets from one MD personality to another + * have to conform to restrictions which are enforced here. + * + * Degration is already checked for in rs_check_conversion() below. + */ +static int rs_check_takeover(struct raid_set *rs) +{ + struct mddev *mddev = &rs->md; + unsigned int near_copies; + + switch (mddev->level) { + case 0: + /* raid0 -> raid1/5 with one disk */ + if ((mddev->new_level == 1 || mddev->new_level == 5) && + mddev->raid_disks == 1) + return 0; + + /* raid0 -> raid10 */ + if (mddev->new_level == 10 && + !(rs->raid_disks % 2)) + return 0; + + /* raid0 with multiple disks -> raid4/5/6 */ + if (_in_range(mddev->new_level, 4, 6) && + mddev->new_layout == ALGORITHM_PARITY_N && + mddev->raid_disks > 1) + return 0; + + break; + + case 10: + /* Can't takeover raid10_offset! */ + if (_is_raid10_offset(mddev->layout)) + break; + + near_copies = _raid10_near_copies(mddev->layout); + + /* raid10* -> raid0 */ + if (mddev->new_level == 0) { + /* Can takeover raid10_near with raid disks divisable by data copies! */ + if (near_copies > 1 && + !(mddev->raid_disks % near_copies)) { + mddev->raid_disks /= near_copies; + mddev->delta_disks = mddev->raid_disks; + return 0; + } + + /* Can takeover raid10_far */ + if (near_copies == 1 && + _raid10_far_copies(mddev->layout) > 1) + return 0; + + break; + } + + /* raid10_{near,far} -> raid1 */ + if (mddev->new_level == 1 && + max(near_copies, _raid10_far_copies(mddev->layout)) == mddev->raid_disks) + return 0; + + /* raid10_{near,far} with 2 disks -> raid4/5 */ + if (_in_range(mddev->new_level, 4, 5) && + mddev->raid_disks == 2) + return 0; + break; + + case 1: + /* raid1 with 2 disks -> raid4/5 */ + if (_in_range(mddev->new_level, 4, 5) && + mddev->raid_disks == 2) { + mddev->degraded = 1; + return 0; + } + + /* raid1 -> raid0 */ + if (mddev->new_level == 0 && + mddev->raid_disks == 1) + return 0; + + /* raid1 -> raid10 */ + if (mddev->new_level == 10) + return 0; + + break; + + case 4: + /* raid4 -> raid0 */ + if (mddev->new_level == 0) + return 0; + + /* raid4 -> raid1/5 with 2 disks */ + if ((mddev->new_level == 1 || mddev->new_level == 5) && + mddev->raid_disks == 2) + return 0; + + /* raid4 -> raid5/6 with parity N */ + if (_in_range(mddev->new_level, 5, 6) && + mddev->layout == ALGORITHM_PARITY_N) + return 0; + break; + + case 5: + /* raid5 with parity N -> raid0 */ + if (mddev->new_level == 0 && + mddev->layout == ALGORITHM_PARITY_N) + return 0; + + /* raid5 with parity N -> raid4 */ + if (mddev->new_level == 4 && + mddev->layout == ALGORITHM_PARITY_N) + return 0; + + /* raid5 with 2 disks -> raid1/4/10 */ + if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) && + mddev->raid_disks == 2) + return 0; + + /* raid5 with parity N -> raid6 with parity N */ + if (mddev->new_level == 6 && + ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) || + _in_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6))) + return 0; + break; + + case 6: + /* raid6 with parity N -> raid0 */ + if (mddev->new_level == 0 && + mddev->layout == ALGORITHM_PARITY_N) + return 0; + + /* raid6 with parity N -> raid4 */ + if (mddev->new_level == 4 && + mddev->layout == ALGORITHM_PARITY_N) + return 0; + + /* raid6_*_n with parity N -> raid5_* */ + if (mddev->new_level == 5 && + ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) || + _in_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC))) + return 0; + + default: + break; + } + + return ti_error_einval(rs->ti, "takeover not possible"); +} + +/* True if @rs requested to be taken over */ +static bool rs_takeover_requested(struct raid_set *rs) +{ + return rs->md.new_level != rs->md.level; +} + /* Features */ -#define FEATURE_FLAG_SUPPORTS_RESHAPE 0x1 +#define FEATURE_FLAG_SUPPORTS_V180 0x1 /* Supports v1.8.0 extended superblock */ +#define FEATURE_FLAG_SUPPORTS_RESHAPE 0x2 /* Supports v1.8.0 reshaping functionality */ /* State flags for sb->flags */ #define SB_FLAG_RESHAPE_ACTIVE 0x1 @@ -1220,7 +1462,7 @@ struct dm_raid_superblock { /******************************************************************** * BELOW FOLLOW V1.8.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!! * - * FEATURE_FLAG_SUPPORTS_RESHAPE in the features member indicates that those exist + * FEATURE_FLAG_SUPPORTS_V180 in the features member indicates that those exist */ __le32 flags; /* Flags defining array states for reshaping */ @@ -1287,7 +1529,7 @@ static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t * failed_devices[0] = le64_to_cpu(sb->failed_devices); memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices)); - if (_test_flag(FEATURE_FLAG_SUPPORTS_RESHAPE, le32_to_cpu(sb->compat_features))) { + if (_test_flag(FEATURE_FLAG_SUPPORTS_V180, le32_to_cpu(sb->compat_features))) { int i = ARRAY_SIZE(sb->extended_failed_devices); while (i--) @@ -1337,7 +1579,7 @@ static void super_sync(struct mddev *mddev, struct md_rdev *rdev) sb_update_failed_devices(sb, failed_devices); sb->magic = cpu_to_le32(DM_RAID_MAGIC); - sb->compat_features = cpu_to_le32(0); /* Don't set reshape flag yet */ + sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V180); /* Don't set reshape flag yet */ sb->num_devices = cpu_to_le32(mddev->raid_disks); sb->array_position = cpu_to_le32(rdev->raid_disk); @@ -1416,6 +1658,7 @@ static int super_load(struct md_rdev *rdev, struct md_rdev *refdev) super_sync(rdev->mddev, rdev); set_bit(FirstUse, &rdev->flags); + sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V180); /* Don't set reshape flag yet */ /* Force writing of superblocks to disk */ set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags); @@ -1461,7 +1704,7 @@ static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev) * Reshaping is supported, e.g. reshape_position is valid * in superblock and superblock content is authoritative. */ - if (_test_flag(FEATURE_FLAG_SUPPORTS_RESHAPE, le32_to_cpu(sb->compat_features))) { + if (_test_flag(FEATURE_FLAG_SUPPORTS_V180, le32_to_cpu(sb->compat_features))) { /* Superblock is authoritative wrt given raid set layout! */ mddev->raid_disks = le32_to_cpu(sb->num_devices); mddev->level = le32_to_cpu(sb->level); @@ -1564,6 +1807,7 @@ static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev) if (new_devs == rs->raid_disks) { DMINFO("Superblocks created for new raid set"); set_bit(MD_ARRAY_FIRST_USE, &mddev->flags); + _set_flag(RT_FLAG_UPDATE_SBS, &rs->runtime_flags); mddev->recovery_cp = 0; } else if (new_devs && new_devs != rs->raid_disks && !rebuilds) { DMERR("New device injected into existing raid set without " @@ -1657,8 +1901,9 @@ static int super_validate(struct raid_set *rs, struct md_rdev *rdev) if (!mddev->events && super_init_validation(rs, rdev)) return -EINVAL; - if (sb->compat_features || sb->incompat_features) { - rs->ti->error = "Unable to assemble array: No feature flags supported yet"; + if (le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V180 || + sb->incompat_features) { + rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet"; return -EINVAL; } @@ -1718,8 +1963,6 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs) * that the "sync" directive is disallowed during the * reshape. */ - rdev->sectors = to_sector(i_size_read(rdev->bdev->bd_inode)); - if (_test_flag(CTR_FLAG_SYNC, rs->ctr_flags)) continue; @@ -1785,14 +2028,77 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs) return 0; } +/* Userpace reordered disks -> adjust raid_disk indexes in @rs */ +static void _reorder_raid_disk_indexes(struct raid_set *rs) +{ + int i = 0; + struct md_rdev *rdev; + + rdev_for_each(rdev, &rs->md) { + rdev->raid_disk = i++; + rdev->saved_raid_disk = rdev->new_raid_disk = -1; + } +} + +/* + * Setup @rs for takeover by a different raid level + */ +static int rs_setup_takeover(struct raid_set *rs) +{ + struct mddev *mddev = &rs->md; + struct md_rdev *rdev; + unsigned int d = mddev->raid_disks = rs->raid_disks; + sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset; + + if (rt_is_raid10(rs->raid_type)) { + if (mddev->level == 0) { + /* Userpace reordered disks -> adjust raid_disk indexes */ + _reorder_raid_disk_indexes(rs); + + /* raid0 -> raid10_far layout */ + mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR, + rs->raid10_copies); + } else if (mddev->level == 1) + /* raid1 -> raid10_near layout */ + mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR, + rs->raid_disks); + else + return -EINVAL; + + } + + clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags); + mddev->recovery_cp = MaxSector; + + while (d--) { + rdev = &rs->dev[d].rdev; + + if (test_bit(d, (void *) rs->rebuild_disks)) { + clear_bit(In_sync, &rdev->flags); + clear_bit(Faulty, &rdev->flags); + mddev->recovery_cp = rdev->recovery_offset = 0; + /* Bitmap has to be created when we do an "up" takeover */ + set_bit(MD_ARRAY_FIRST_USE, &mddev->flags); + } + + rdev->new_data_offset = new_data_offset; + } + + rs_set_new(rs); + set_bit(MD_CHANGE_DEVS, &mddev->flags); + + return 0; +} + /* * Enable/disable discard support on RAID set depending on * RAID level and discard properties of underlying RAID members. */ -static void configure_discard_support(struct dm_target *ti, struct raid_set *rs) +static void configure_discard_support(struct raid_set *rs) { int i; bool raid456; + struct dm_target *ti = rs->ti; /* Assume discards not supported until after checks below. */ ti->discards_supported = false; @@ -1894,6 +2200,14 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv) goto bad; rs->md.sync_super = super_sync; + + /* + * Backup any new raid set level, layout, ... + * requested to be able to compare to superblock + * members for conversion decisions. + */ + rs_config_backup(rs); + r = analyse_superblocks(ti, rs); if (r) goto bad; @@ -1902,10 +2216,29 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv) ti->private = rs; ti->num_flush_bios = 1; + /* Restore any requested new layout for conversion decision */ + rs_config_restore(rs); + /* - * Disable/enable discard support on RAID set. + * If a takeover is needed, just set the level to + * the new requested one and allow the raid set to run. */ - configure_discard_support(ti, rs); + if (rs_takeover_requested(rs)) { + r = rs_check_takeover(rs); + if (r) + return r; + + r = rs_setup_takeover(rs); + if (r) + return r; + + _set_flag(RT_FLAG_UPDATE_SBS, &rs->runtime_flags); + } + + /* Start raid set read-only and assumed clean to change in raid_resume() */ + rs->md.ro = 1; + rs->md.in_sync = 1; + set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery); /* Has to be held on running the array */ mddev_lock_nointr(&rs->md); @@ -2312,29 +2645,92 @@ static void attempt_restore_of_faulty_devices(struct raid_set *rs) } } +/* Load the dirty region bitmap */ +static int _bitmap_load(struct raid_set *rs) +{ + int r = 0; + + /* Try loading the bitmap unless "raid0", which does not have one */ + if (!rs_is_raid0(rs) && + !_test_and_set_flag(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) { + r = bitmap_load(&rs->md); + if (r) + DMERR("Failed to load bitmap"); + } + + return r; +} + +static int raid_preresume(struct dm_target *ti) +{ + struct raid_set *rs = ti->private; + struct mddev *mddev = &rs->md; + + /* This is a resume after a suspend of the set -> it's already started */ + if (_test_and_set_flag(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags)) + return 0; + + /* + * The superblocks need to be updated on disk if the + * array is new or _bitmap_load will overwrite them + * in core with old data. + * + * In case the array got modified (takeover/reshape/resize) + * or the data offsets on the component devices changed, they + * have to be updated as well. + * + * Have to switch to readwrite and back in order to + * allow for the superblock updates. + */ + if (_test_and_clear_flag(RT_FLAG_UPDATE_SBS, &rs->runtime_flags)) { + set_bit(MD_CHANGE_DEVS, &mddev->flags); + mddev->ro = 0; + md_update_sb(mddev, 1); + mddev->ro = 1; + } + + /* + * Disable/enable discard support on raid set after any + * conversion, because devices can have been added + */ + configure_discard_support(rs); + + /* Load the bitmap from disk unless raid0 */ + return _bitmap_load(rs); +} + static void raid_resume(struct dm_target *ti) { struct raid_set *rs = ti->private; + struct mddev *mddev = &rs->md; - if (!rt_is_raid0(rs->raid_type)) { - set_bit(MD_CHANGE_DEVS, &rs->md.flags); + if (_test_and_set_flag(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) { + /* + * A secondary resume while the device is active. + * Take this opportunity to check whether any failed + * devices are reachable again. + */ + attempt_restore_of_faulty_devices(rs); - if (!rs->bitmap_loaded) { - bitmap_load(&rs->md); - rs->bitmap_loaded = 1; - } else { - /* - * A secondary resume while the device is active. - * Take this opportunity to check whether any failed - * devices are reachable again. - */ - attempt_restore_of_faulty_devices(rs); - } + } else { + mddev->in_sync = 0; - clear_bit(MD_RECOVERY_FROZEN, &rs->md.recovery); + /* + * If any of the constructor flags got passed in + * but "region_size" (gets always passed in for + * mappings with bitmap), we expect userspace to + * reset them and reload the mapping anyway. + * + * -> don't unfreeze resynchronization until imminant + * reload of the table w/o theses flags + */ + if (!_test_flags(ALL_FREEZE_FLAGS, rs->ctr_flags)) + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); } - mddev_resume(&rs->md); + mddev->ro = 0; + if (mddev->suspended) + mddev_resume(mddev); } static struct target_type raid_target = { @@ -2350,6 +2746,7 @@ static struct target_type raid_target = { .io_hints = raid_io_hints, .presuspend = raid_presuspend, .postsuspend = raid_postsuspend, + .preresume = raid_preresume, .resume = raid_resume, }; -- 2.20.1