From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.burntcomma.com (mail2.burntcomma.com [217.169.27.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C336532AACA for ; Wed, 7 Jan 2026 14:10:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.169.27.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767795029; cv=none; b=Pae7NhdEls5DNye+TR6MPznWOpMuhopXjUiFXupARP9fTMQpwqex85chn1LHyxm2tYaIjZlsP4v0G9QKfUvKxYS+FA2PWmCmIV0B+43lvQgHfWVEpKn1J5jmd2qHGD935MT9i6Sl4bmA80jY5XqmxghWGd2dote0G4yqtUrvZo8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767795029; c=relaxed/simple; bh=NHd/kJtXB1AL8Hm2ta3WxJ56r8mNMPAX5+Ek5V49/wQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Mime-Version; b=IdfxCXbWMamKQibCrZxqQ6w5KXsjSejr1OL4Ma+qmvYUg46HNa2xiGJEUD0RsR93yyv+SWfw2k7RkfNyQeH8oyeEsnOsbVY5N++qJ29sbRbLegRRc3Tt6fNA25LjXN9c3/5pgnuJpq+bD3LmCj3d2F01O/duWTUkKQLAQud4WlQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=harmstone.com; spf=pass smtp.mailfrom=harmstone.com; dkim=pass (1024-bit key) header.d=harmstone.com header.i=@harmstone.com header.b=6hvB3n6C; arc=none smtp.client-ip=217.169.27.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=harmstone.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=harmstone.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=harmstone.com header.i=@harmstone.com header.b="6hvB3n6C" Received: from beren (beren.burntcomma.com [IPv6:2a02:8012:8cf0:0:ce28:aaff:fe0d:6db2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by mail.burntcomma.com (Postfix) with ESMTPSA id 21CDA2F1868; Wed, 7 Jan 2026 14:10:18 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=harmstone.com; s=mail; t=1767795018; bh=toeBrCWG1/8FeGQmVllLuH3IGj7OI2Wv49Sb7JJ7oUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=6hvB3n6Cuwd+xz2r3+Z/zGoB2iqb/TM+K4g/q4Ov7ECcozwSPn2pEB+DP+R5COG2+ CnblPUpJRWuLJRx2mAPR7xXusEvKNJzVPkfdz59npzQYxtcSpG3NVvvG9ixFesOEJu pxx2XwPM5/vXVY7PZOEeoF/PajzI8iR2cvZYmaoU= From: Mark Harmstone To: linux-btrfs@vger.kernel.org Cc: Mark Harmstone , Boris Burkov Subject: [PATCH v8 02/17] btrfs: add METADATA_REMAP chunk type Date: Wed, 7 Jan 2026 14:09:02 +0000 Message-ID: <20260107141015.25819-3-mark@harmstone.com> In-Reply-To: <20260107141015.25819-1-mark@harmstone.com> References: <20260107141015.25819-1-mark@harmstone.com> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Add a new METADATA_REMAP chunk type, which is a metadata chunk that holds the remap tree. This is needed for bootstrapping purposes: the remap tree can't itself be remapped, and must be relocated the existing way, by COWing every leaf. The remap tree can't go in the SYSTEM chunk as space there is limited, because a copy of the chunk item gets placed in the superblock. The changes in fs/btrfs/volumes.h are because we're adding a new block group type bit after the profile bits, and so can no longer rely on the const_ilog2 trick. The sizing to 32MB per chunk, matching the SYSTEM chunk, is an estimate here, we can adjust it later if it proves to be too big or too small. This works out to be ~500,000 remap items, which for a 4KB block size covers ~2GB of remapped data in the worst case and ~500TB in the best case. Signed-off-by: Mark Harmstone Reviewed-by: Boris Burkov --- fs/btrfs/block-rsv.c | 9 +++++++++ fs/btrfs/block-rsv.h | 1 + fs/btrfs/disk-io.c | 1 + fs/btrfs/fs.h | 2 ++ fs/btrfs/space-info.c | 13 ++++++++++++- fs/btrfs/sysfs.c | 2 ++ fs/btrfs/tree-checker.c | 13 +++++++++++-- fs/btrfs/volumes.c | 3 +++ fs/btrfs/volumes.h | 10 +++++++++- include/uapi/linux/btrfs_tree.h | 4 +++- 10 files changed, 53 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c index 96cf7a162987..2781abf18f26 100644 --- a/fs/btrfs/block-rsv.c +++ b/fs/btrfs/block-rsv.c @@ -419,6 +419,9 @@ void btrfs_init_root_block_rsv(struct btrfs_root *root) case BTRFS_TREE_LOG_OBJECTID: root->block_rsv = &fs_info->treelog_rsv; break; + case BTRFS_REMAP_TREE_OBJECTID: + root->block_rsv = &fs_info->remap_block_rsv; + break; default: root->block_rsv = NULL; break; @@ -432,6 +435,10 @@ void btrfs_init_global_block_rsv(struct btrfs_fs_info *fs_info) space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM); fs_info->chunk_block_rsv.space_info = space_info; + space_info = btrfs_find_space_info(fs_info, + BTRFS_BLOCK_GROUP_METADATA_REMAP); + fs_info->remap_block_rsv.space_info = space_info; + space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA); fs_info->global_block_rsv.space_info = space_info; fs_info->trans_block_rsv.space_info = space_info; @@ -458,6 +465,8 @@ void btrfs_release_global_block_rsv(struct btrfs_fs_info *fs_info) WARN_ON(fs_info->trans_block_rsv.reserved > 0); WARN_ON(fs_info->chunk_block_rsv.size > 0); WARN_ON(fs_info->chunk_block_rsv.reserved > 0); + WARN_ON(fs_info->remap_block_rsv.size > 0); + WARN_ON(fs_info->remap_block_rsv.reserved > 0); WARN_ON(fs_info->delayed_block_rsv.size > 0); WARN_ON(fs_info->delayed_block_rsv.reserved > 0); WARN_ON(fs_info->delayed_refs_rsv.reserved > 0); diff --git a/fs/btrfs/block-rsv.h b/fs/btrfs/block-rsv.h index 79ae9d05cd91..8359fb96bc3c 100644 --- a/fs/btrfs/block-rsv.h +++ b/fs/btrfs/block-rsv.h @@ -22,6 +22,7 @@ enum btrfs_rsv_type { BTRFS_BLOCK_RSV_DELALLOC, BTRFS_BLOCK_RSV_TRANS, BTRFS_BLOCK_RSV_CHUNK, + BTRFS_BLOCK_RSV_REMAP, BTRFS_BLOCK_RSV_DELOPS, BTRFS_BLOCK_RSV_DELREFS, BTRFS_BLOCK_RSV_TREELOG, diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index cecb81d0f9e0..cbfb7127b528 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2773,6 +2773,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info) BTRFS_BLOCK_RSV_GLOBAL); btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS); btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK); + btrfs_init_block_rsv(&fs_info->remap_block_rsv, BTRFS_BLOCK_RSV_REMAP); btrfs_init_block_rsv(&fs_info->treelog_rsv, BTRFS_BLOCK_RSV_TREELOG); btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY); btrfs_init_block_rsv(&fs_info->delayed_block_rsv, diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h index 0dc851b9c51b..46c4f1dcec47 100644 --- a/fs/btrfs/fs.h +++ b/fs/btrfs/fs.h @@ -501,6 +501,8 @@ struct btrfs_fs_info { struct btrfs_block_rsv trans_block_rsv; /* Block reservation for chunk tree */ struct btrfs_block_rsv chunk_block_rsv; + /* Block reservation for remap tree. */ + struct btrfs_block_rsv remap_block_rsv; /* Block reservation for delayed operations */ struct btrfs_block_rsv delayed_block_rsv; /* Block reservation for delayed refs */ diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 7b7b7255f7d8..badebe6e0b34 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -215,7 +215,7 @@ static u64 calc_chunk_size(const struct btrfs_fs_info *fs_info, u64 flags) if (flags & BTRFS_BLOCK_GROUP_DATA) return BTRFS_MAX_DATA_CHUNK_SIZE; - else if (flags & BTRFS_BLOCK_GROUP_SYSTEM) + else if (flags & (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA_REMAP)) return SZ_32M; /* Handle BTRFS_BLOCK_GROUP_METADATA */ @@ -344,6 +344,8 @@ int btrfs_init_space_info(struct btrfs_fs_info *fs_info) if (mixed) { flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA; ret = create_space_info(fs_info, flags); + if (ret) + goto out; } else { flags = BTRFS_BLOCK_GROUP_METADATA; ret = create_space_info(fs_info, flags); @@ -352,7 +354,15 @@ int btrfs_init_space_info(struct btrfs_fs_info *fs_info) flags = BTRFS_BLOCK_GROUP_DATA; ret = create_space_info(fs_info, flags); + if (ret) + goto out; + } + + if (features & BTRFS_FEATURE_INCOMPAT_REMAP_TREE) { + flags = BTRFS_BLOCK_GROUP_METADATA_REMAP; + ret = create_space_info(fs_info, flags); } + out: return ret; } @@ -607,6 +617,7 @@ static void dump_global_block_rsv(struct btrfs_fs_info *fs_info) DUMP_BLOCK_RSV(fs_info, global_block_rsv); DUMP_BLOCK_RSV(fs_info, trans_block_rsv); DUMP_BLOCK_RSV(fs_info, chunk_block_rsv); + DUMP_BLOCK_RSV(fs_info, remap_block_rsv); DUMP_BLOCK_RSV(fs_info, delayed_block_rsv); DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv); } diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 0e2ed8072443..0213a3c44628 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -1972,6 +1972,8 @@ static const char *alloc_name(struct btrfs_space_info *space_info) case BTRFS_BLOCK_GROUP_SYSTEM: ASSERT(space_info->subgroup_id == BTRFS_SUB_GROUP_PRIMARY); return "system"; + case BTRFS_BLOCK_GROUP_METADATA_REMAP: + return "metadata-remap"; default: WARN_ON(1); return "invalid-combination"; diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index aedc208a95b8..a6c158cd8fcd 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -748,17 +748,26 @@ static int check_block_group_item(struct extent_buffer *leaf, return -EUCLEAN; } + if (unlikely(flags & BTRFS_BLOCK_GROUP_METADATA_REMAP && + !btrfs_fs_incompat(fs_info, REMAP_TREE))) { + block_group_err(leaf, slot, +"invalid flags, have 0x%llx (METADATA_REMAP flag set) but no remap-tree incompat flag", + flags); + return -EUCLEAN; + } + type = flags & BTRFS_BLOCK_GROUP_TYPE_MASK; if (unlikely(type != BTRFS_BLOCK_GROUP_DATA && type != BTRFS_BLOCK_GROUP_METADATA && type != BTRFS_BLOCK_GROUP_SYSTEM && + type != BTRFS_BLOCK_GROUP_METADATA_REMAP && type != (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA))) { block_group_err(leaf, slot, -"invalid type, have 0x%llx (%lu bits set) expect either 0x%llx, 0x%llx, 0x%llx or 0x%llx", +"invalid type, have 0x%llx (%lu bits set) expect either 0x%llx, 0x%llx, 0x%llx, 0x%llx or 0x%llx", type, hweight64(type), BTRFS_BLOCK_GROUP_DATA, BTRFS_BLOCK_GROUP_METADATA, - BTRFS_BLOCK_GROUP_SYSTEM, + BTRFS_BLOCK_GROUP_SYSTEM, BTRFS_BLOCK_GROUP_METADATA_REMAP, BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA); return -EUCLEAN; } diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 1134474926ff..07d42ba38d7d 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -231,6 +231,9 @@ void btrfs_describe_block_groups(u64 bg_flags, char *buf, u32 size_buf) DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_DATA, "data"); DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_SYSTEM, "system"); DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_METADATA, "metadata"); + /* Block groups containing the remap tree. */ + DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_METADATA_REMAP, "metadata-remap"); + /* Block group that has been remapped. */ DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_REMAPPED, "remapped"); DESCRIBE_FLAG(BTRFS_AVAIL_ALLOC_BIT_SINGLE, "single"); diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 34b854c1a303..4117fabb248b 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -58,7 +58,6 @@ static_assert(ilog2(BTRFS_STRIPE_LEN) == BTRFS_STRIPE_LEN_SHIFT); */ static_assert(const_ffs(BTRFS_BLOCK_GROUP_RAID0) < const_ffs(BTRFS_BLOCK_GROUP_PROFILE_MASK & ~BTRFS_BLOCK_GROUP_RAID0)); -static_assert(ilog2(BTRFS_BLOCK_GROUP_RAID0) > ilog2(BTRFS_BLOCK_GROUP_TYPE_MASK)); /* ilog2() can handle both constants and variables */ #define BTRFS_BG_FLAG_TO_INDEX(profile) \ @@ -80,6 +79,15 @@ enum btrfs_raid_types { BTRFS_NR_RAID_TYPES }; +static_assert(BTRFS_RAID_RAID0 == 1); +static_assert(BTRFS_RAID_RAID1 == 2); +static_assert(BTRFS_RAID_DUP == 3); +static_assert(BTRFS_RAID_RAID10 == 4); +static_assert(BTRFS_RAID_RAID5 == 5); +static_assert(BTRFS_RAID_RAID6 == 6); +static_assert(BTRFS_RAID_RAID1C3 == 7); +static_assert(BTRFS_RAID_RAID1C4 == 8); + /* * Use sequence counter to get consistent device stat data on * 32-bit processors. diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h index f011d34cb699..76578426671c 100644 --- a/include/uapi/linux/btrfs_tree.h +++ b/include/uapi/linux/btrfs_tree.h @@ -1169,12 +1169,14 @@ struct btrfs_dev_replace_item { #define BTRFS_BLOCK_GROUP_RAID1C3 (1ULL << 9) #define BTRFS_BLOCK_GROUP_RAID1C4 (1ULL << 10) #define BTRFS_BLOCK_GROUP_REMAPPED (1ULL << 11) +#define BTRFS_BLOCK_GROUP_METADATA_REMAP (1ULL << 12) #define BTRFS_BLOCK_GROUP_RESERVED (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \ BTRFS_SPACE_INFO_GLOBAL_RSV) #define BTRFS_BLOCK_GROUP_TYPE_MASK (BTRFS_BLOCK_GROUP_DATA | \ BTRFS_BLOCK_GROUP_SYSTEM | \ - BTRFS_BLOCK_GROUP_METADATA) + BTRFS_BLOCK_GROUP_METADATA | \ + BTRFS_BLOCK_GROUP_METADATA_REMAP) #define BTRFS_BLOCK_GROUP_PROFILE_MASK (BTRFS_BLOCK_GROUP_RAID0 | \ BTRFS_BLOCK_GROUP_RAID1 | \ -- 2.51.2