From fe5d2f4a15967bbe907e7b3e31e49dae7af7cc6b Mon Sep 17 00:00:00 2001 From: Jonathan Brassow Date: Thu, 21 Feb 2013 13:28:10 +1100 Subject: DM RAID: Add support for MD's RAID10 "far" and "offset" algorithms DM RAID: Add support for MD's RAID10 "far" and "offset" algorithms Until now, dm-raid.c only supported the "near" algorthm of MD's RAID10 implementation. This patch adds support for the "far" and "offset" algorithms, but only with the improved redundancy that is brought with the introduction of the 'use_far_sets' bit, which shifts copied stripes according to smaller sets vs the entire array. That is, the 17th bit of the 'layout' variable that defines the RAID10 implementation will always be set. (More information on how the 'layout' variable selects the RAID10 algorithm can be found in the opening comments of drivers/md/raid10.c.) Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown --- drivers/md/dm-raid.c | 123 ++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 103 insertions(+), 20 deletions(-) (limited to 'drivers/md/dm-raid.c') 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 ] Layout algorithm. (Default: near) + * [raid10_format ] 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); } -- cgit v1.2.3 From fd7c092e711ebab55b2688d3859d95dfd0301f73 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 1 Mar 2013 22:45:44 +0000 Subject: dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'drivers/md/dm-raid.c') diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 9e58dbd8d8cb..5a578d89da2d 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -1201,8 +1201,8 @@ static int raid_map(struct dm_target *ti, struct bio *bio) return DM_MAPIO_SUBMITTED; } -static int raid_status(struct dm_target *ti, status_type_t type, - unsigned status_flags, char *result, unsigned maxlen) +static void raid_status(struct dm_target *ti, status_type_t type, + unsigned status_flags, char *result, unsigned maxlen) { struct raid_set *rs = ti->private; unsigned raid_param_cnt = 1; /* at least 1 for chunksize */ @@ -1344,8 +1344,6 @@ static int raid_status(struct dm_target *ti, status_type_t type, DMEMIT(" -"); } } - - return 0; } static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) @@ -1405,7 +1403,7 @@ static void raid_resume(struct dm_target *ti) static struct target_type raid_target = { .name = "raid", - .version = {1, 4, 1}, + .version = {1, 4, 2}, .module = THIS_MODULE, .ctr = raid_ctr, .dtr = raid_dtr, -- cgit v1.2.3 From 55a62eef8d1b50ceff3b7bf46851103bdcc7e5b0 Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Fri, 1 Mar 2013 22:45:47 +0000 Subject: dm: rename request variables to bios Use 'bio' in the name of variables and functions that deal with bios rather than 'request' to avoid confusion with the normal block layer use of 'request'. No functional changes. Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/md/dm-raid.c') diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 5a578d89da2d..9a01d1e4c783 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -1151,7 +1151,7 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv) INIT_WORK(&rs->md.event_work, do_table_event); ti->private = rs; - ti->num_flush_requests = 1; + ti->num_flush_bios = 1; mutex_lock(&rs->md.reconfig_mutex); ret = md_run(&rs->md); -- cgit v1.2.3