From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-34-i6.italiaonline.it ([213.209.14.34]:51511 "EHLO libero.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731639AbeGMVSZ (ORCPT ); Fri, 13 Jul 2018 17:18:25 -0400 Reply-To: kreijack@inwind.it Subject: Re: [PATCH 2/4] btrfs: add support for 3-copy replication (raid1c3) To: David Sterba , linux-btrfs@vger.kernel.org References: <7b570d84f5232322564e49f88990b733234c372c.1531503452.git.dsterba@suse.com> From: Goffredo Baroncelli Message-ID: <16e66925-bf9e-57d6-b6c0-a8b03c8d38c9@libero.it> Date: Fri, 13 Jul 2018 23:02:03 +0200 MIME-Version: 1.0 In-Reply-To: <7b570d84f5232322564e49f88990b733234c372c.1531503452.git.dsterba@suse.com> Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: As general comment, good to hear that something is moving around raid5/6 + write hole and multiple mirroring. However I am guessing if this is time to simplify the RAID code. There are a lot of "if" which could be avoided using the values stored in the array "btrfs_raid_array[]". Below some comments: On 07/13/2018 08:46 PM, David Sterba wrote: > Add new block group profile to store 3 copies in a simliar way that > current RAID1 does. The profile name is temporary and may change in the > future. > > Signed-off-by: David Sterba > --- > fs/btrfs/extent-tree.c | 6 +++++ > fs/btrfs/relocation.c | 1 + > fs/btrfs/scrub.c | 3 ++- > fs/btrfs/super.c | 3 +++ > fs/btrfs/volumes.c | 40 ++++++++++++++++++++++++++++----- > fs/btrfs/volumes.h | 2 ++ > include/uapi/linux/btrfs.h | 3 ++- > include/uapi/linux/btrfs_tree.h | 3 +++ > 8 files changed, 53 insertions(+), 8 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 4ffa64e288da..47f929dcc3d4 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -7527,6 +7527,7 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info, > if (!block_group_bits(block_group, flags)) { > u64 extra = BTRFS_BLOCK_GROUP_DUP | > BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3 | > BTRFS_BLOCK_GROUP_RAID5 | > BTRFS_BLOCK_GROUP_RAID6 | > BTRFS_BLOCK_GROUP_RAID10; "extra" could be created iterating on btrfs_raid_array[] and considering only the item with ncopies > 1; or we could add #define BTRFS_BLOCK_GROUP_REDUNDANCY (BTRFS_BLOCK_GROUP_DUP| .....) This constant could be used also below > @@ -9330,6 +9331,8 @@ static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags) > > num_devices = fs_info->fs_devices->rw_devices; > > + ASSERT(!(flags & BTRFS_BLOCK_GROUP_RAID1C3)); > + > stripped = BTRFS_BLOCK_GROUP_RAID0 | > BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 | > BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10; > @@ -9647,6 +9650,8 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr) > min_free >>= 1; > } else if (index == BTRFS_RAID_RAID1) { > dev_min = 2; > + } else if (index == BTRFS_RAID_RAID1C3) { > + dev_min = 3; > } else if (index == BTRFS_RAID_DUP) { > /* Multiply by 2 */ > min_free <<= 1; The "if"s above could be simplified as: dev_min = btrfs_raid_array[index].devs_min; if (index == BTRFS_RAID_DUP) min_free <<= 1; else if (index == BTRFS_RAID_RAID0) min_free = div64_u64(min_free, dev_min); else if (index == BTRFS_RAID_RAID10) min_free >>= 1; > @@ -10141,6 +10146,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) > if (!(get_alloc_profile(info, space_info->flags) & > (BTRFS_BLOCK_GROUP_RAID10 | > BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3 | > BTRFS_BLOCK_GROUP_RAID5 | > BTRFS_BLOCK_GROUP_RAID6 | > BTRFS_BLOCK_GROUP_DUP))) See above about BTRFS_BLOCK_GROUP_REDUNDANCY > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index 879b76fa881a..fea9e7e96b87 100644 > --- a/fs/btrfs/relocation.c > +++ b/fs/btrfs/relocation.c > @@ -4339,6 +4339,7 @@ static void describe_relocation(struct btrfs_fs_info *fs_info, > DESCRIBE_FLAG(METADATA, "metadata"); The code below, could be performed searching in the array btrfs_raid_array[] instead of checking each possibility > DESCRIBE_FLAG(RAID0, "raid0"); > DESCRIBE_FLAG(RAID1, "raid1"); > + DESCRIBE_FLAG(RAID1C3, "raid1c3"); > DESCRIBE_FLAG(DUP, "dup"); > DESCRIBE_FLAG(RAID10, "raid10"); > DESCRIBE_FLAG(RAID5, "raid5"); > diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c > index 572306036477..e9355759f2ec 100644 > --- a/fs/btrfs/scrub.c > +++ b/fs/btrfs/scrub.c > @@ -3388,7 +3388,8 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, > offset = map->stripe_len * (num / map->sub_stripes); > increment = map->stripe_len * factor; > mirror_num = num % map->sub_stripes + 1; > - } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) { > + } else if (map->type & (BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3)) { > increment = map->stripe_len; > mirror_num = num % map->num_stripes + 1; > } else if (map->type & BTRFS_BLOCK_GROUP_DUP) { > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index 4f646b66cc06..86e6aa5ef788 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -1977,6 +1977,9 @@ static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info, > } else if (type & BTRFS_BLOCK_GROUP_RAID1) { > min_stripes = 2; > num_stripes = 2; > + } else if (type & BTRFS_BLOCK_GROUP_RAID1C3) { > + min_stripes = 3; > + num_stripes = 3; > } else if (type & BTRFS_BLOCK_GROUP_RAID10) { > min_stripes = 4; > num_stripes = 4; > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 45635f4d78c8..0920b31e999d 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -116,6 +116,18 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = { > .bg_flag = BTRFS_BLOCK_GROUP_RAID6, > .mindev_error = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET, > }, > + [BTRFS_RAID_RAID1C3] = { > + .sub_stripes = 1, > + .dev_stripes = 1, > + .devs_max = 0, > + .devs_min = 3, > + .tolerated_failures = 2, > + .devs_increment = 3, > + .ncopies = 3, > + .raid_name = "raid1c3", > + .bg_flag = BTRFS_BLOCK_GROUP_RAID1C3, > + .mindev_error = BTRFS_ERROR_DEV_RAID1C3_MIN_NOT_MET, > + }, > }; > > const char *get_raid_name(enum btrfs_raid_types type) > @@ -3336,6 +3348,8 @@ static int chunk_drange_filter(struct extent_buffer *leaf, > if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP | > BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) { > factor = num_stripes / 2; > + } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID1C3) { > + factor = num_stripes / 3; > } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) { > factor = num_stripes - 1; > } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) { May be time to add two other fields to the btrfs_raid_array[] array ? I.e.: factor_div and factor_sub so factor could be computed as index = btrfs_bg_flags_to_raid_index(btrfs_chunk_type(leaf, chunk)) factor = num_stripes / btrfs_raid_array[index].factor_div - btrfs_raid_array[index].factor_sub; > @@ -3822,7 +3836,7 @@ int btrfs_balance(struct btrfs_fs_info *fs_info, > if (num_devices > 1) > allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1); > if (num_devices > 2) > - allowed |= BTRFS_BLOCK_GROUP_RAID5; > + allowed |= BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID1C3; > if (num_devices > 3) > allowed |= (BTRFS_BLOCK_GROUP_RAID10 | > BTRFS_BLOCK_GROUP_RAID6); The "if"s below could be replaced by a search in the btrfs_raid_array[] > @@ -3856,6 +3870,7 @@ int btrfs_balance(struct btrfs_fs_info *fs_info, > > /* allow to reduce meta or sys integrity only if force set */ > allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3 | > BTRFS_BLOCK_GROUP_RAID10 | > BTRFS_BLOCK_GROUP_RAID5 | > BTRFS_BLOCK_GROUP_RAID6; See above about BTRFS_BLOCK_GROUP_REDUNDANCY > @@ -4787,8 +4802,11 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans, > sort(devices_info, ndevs, sizeof(struct btrfs_device_info), > btrfs_cmp_device_info, NULL); > > - /* round down to number of usable stripes */ > - ndevs = round_down(ndevs, devs_increment); > + /* > + * Round down to number of usable stripes, devs_increment can be any > + * number so we can't use round_down() > + */ > + ndevs -= ndevs % devs_increment; > > if (ndevs < devs_min) { > ret = -ENOSPC; > @@ -5075,6 +5093,8 @@ static inline int btrfs_chunk_max_errors(struct map_lookup *map) > BTRFS_BLOCK_GROUP_RAID5 | > BTRFS_BLOCK_GROUP_DUP)) { > max_errors = 1; > + } else if (map->type & BTRFS_BLOCK_GROUP_RAID1C3) { > + max_errors = 2; > } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) { > max_errors = 2; > } else { Even in this case the ifs above could be replaced with something like: index = btrfs_bg_flags_to_raid_index(map->type) max_errors = btrfs_raid_array[index].ncopies-1; > @@ -5163,7 +5183,8 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len) > return 1; > > map = em->map_lookup; > - if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1)) > + if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3)) > ret = map->num_stripes; > else if (map->type & BTRFS_BLOCK_GROUP_RAID10) > ret = map->sub_stripes; With the exception of RAID6 case (which I don't understand), the ifs above could be replaced with index = btrfs_bg_flags_to_raid_index(map->type) ret = btrfs_raid_array[index].ncopies > @@ -5237,7 +5258,9 @@ static int find_live_mirror(struct btrfs_fs_info *fs_info, > struct btrfs_device *srcdev; > > ASSERT((map->type & > - (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))); > + (BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3 | > + BTRFS_BLOCK_GROUP_RAID10))); > > if (map->type & BTRFS_BLOCK_GROUP_RAID10) > num_stripes = map->sub_stripes; > @@ -5427,6 +5450,7 @@ static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info, > div_u64_rem(stripe_nr_end - 1, factor, &last_stripe); > last_stripe *= sub_stripes; > } else if (map->type & (BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3 | > BTRFS_BLOCK_GROUP_DUP)) { > num_stripes = map->num_stripes; > } else { > @@ -5792,7 +5816,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, > &stripe_index); > if (!need_full_stripe(op)) > mirror_num = 1; > - } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) { > + } else if (map->type & (BTRFS_BLOCK_GROUP_RAID1 | > + BTRFS_BLOCK_GROUP_RAID1C3)) { > if (need_full_stripe(op)) > num_stripes = map->num_stripes; > else if (mirror_num) > @@ -6441,6 +6466,7 @@ static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info, > } > if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) || > (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) || > + (type & BTRFS_BLOCK_GROUP_RAID1C3 && num_stripes < 3) || > (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) || > (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) || > (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) || The check above could be translate in specific check for BTRFS_BLOCK_GROUP_DUP and BTRFS_BLOCK_GROUP_RAID10; for the other cases we could check that num_stripes is >= devs_min > @@ -7389,5 +7415,7 @@ int btrfs_bg_type_to_factor(u64 flags) > if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | > BTRFS_BLOCK_GROUP_RAID10)) > return 2; > + if (flags & BTRFS_BLOCK_GROUP_RAID1C3) > + return 3; > return 1; > } Even the function above could be replaced with something more general int btrfs_bg_type_to_factor(u64 flags) { if (flags & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) return 1; return btrfs_raid_array[btrfs_bg_flags_to_raid_index(flags)] } > diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h > index c7b9ad9733ea..5be624896dad 100644 > --- a/fs/btrfs/volumes.h > +++ b/fs/btrfs/volumes.h > @@ -537,6 +537,8 @@ static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags) > return BTRFS_RAID_RAID10; > else if (flags & BTRFS_BLOCK_GROUP_RAID1) > return BTRFS_RAID_RAID1; > + else if (flags & BTRFS_BLOCK_GROUP_RAID1C3) > + return BTRFS_RAID_RAID1C3; > else if (flags & BTRFS_BLOCK_GROUP_DUP) > return BTRFS_RAID_DUP; > else if (flags & BTRFS_BLOCK_GROUP_RAID0) What about iterating on btrfs_raid_array[] in the above function > diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h > index 5ca1d21fc4a7..137952d3375d 100644 > --- a/include/uapi/linux/btrfs.h > +++ b/include/uapi/linux/btrfs.h > @@ -825,7 +825,8 @@ enum btrfs_err_code { > BTRFS_ERROR_DEV_TGT_REPLACE, > BTRFS_ERROR_DEV_MISSING_NOT_FOUND, > BTRFS_ERROR_DEV_ONLY_WRITABLE, > - BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS > + BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS, > + BTRFS_ERROR_DEV_RAID1C3_MIN_NOT_MET, > }; > > #define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \ > diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h > index aff1356c2bb8..fa75b63dd928 100644 > --- a/include/uapi/linux/btrfs_tree.h > +++ b/include/uapi/linux/btrfs_tree.h > @@ -836,6 +836,7 @@ struct btrfs_dev_replace_item { > #define BTRFS_BLOCK_GROUP_RAID10 (1ULL << 6) > #define BTRFS_BLOCK_GROUP_RAID5 (1ULL << 7) > #define BTRFS_BLOCK_GROUP_RAID6 (1ULL << 8) > +#define BTRFS_BLOCK_GROUP_RAID1C3 (1ULL << 9) > #define BTRFS_BLOCK_GROUP_RESERVED (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \ > BTRFS_SPACE_INFO_GLOBAL_RSV) > > @@ -847,6 +848,7 @@ enum btrfs_raid_types { > BTRFS_RAID_SINGLE, > BTRFS_RAID_RAID5, > BTRFS_RAID_RAID6, > + BTRFS_RAID_RAID1C3, > BTRFS_NR_RAID_TYPES > }; > > @@ -856,6 +858,7 @@ enum btrfs_raid_types { > > #define BTRFS_BLOCK_GROUP_PROFILE_MASK (BTRFS_BLOCK_GROUP_RAID0 | \ > BTRFS_BLOCK_GROUP_RAID1 | \ > + BTRFS_BLOCK_GROUP_RAID1C3 | \ > BTRFS_BLOCK_GROUP_RAID5 | \ > BTRFS_BLOCK_GROUP_RAID6 | \ > BTRFS_BLOCK_GROUP_DUP | \ > -- gpg @keyserver.linux.it: Goffredo Baroncelli Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5