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 339B232FA30 for ; Wed, 7 Jan 2026 14:10:34 +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=1767795037; cv=none; b=sA5YCinMbPHmSaTf4MF+590P4Mcm4QP+NcwztwTElaevOIynKAu0YU6XwwOGVIczHNYmxeZejEHcdW0D/5J2HV8Et6pC7QshpbES75v4HGL0JQ/gKgm08ud223FGP9FKLQFVAz860barXBSwb/eV53XoTz8f/m4ZYE/g8F79gC8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767795037; c=relaxed/simple; bh=V88DlFOt850Z2zDv3QUa9CPxk/lgYvUGYJt7j8mm0UQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Mime-Version; b=AF0HUx/oHd0WvjRb4f3DvTjsOqYzA+owN83p9bJ9lfRFMqztGB5tHo0oX8eiOANeSHuV2RlzcLclNKZZyG30RG9Z7ou1DNcKm5a95x09OyW7C5K+vmqxogmeUADbgzDbWt34i3ZwxznU4tFXinDMQnsNXI+p0eM1zblK0SkwqwU= 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=YbE1nkZs; 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="YbE1nkZs" 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 DA3F02F1877; 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=G9aIpf5/VEr5CBf1BCfURs+YdQ/5PW4PoVSFQnEjJVM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YbE1nkZseITM7xpYhxqwEtgfEqQrNX156NsHZmz4F/RxJApfFSpM6QoYD5VTaRPdb VbkJQtee4WAJc9Vb1U1ncxo2ifQ8nvTIoC9ukcprvH1d1tafJ+RJDGCpU7hzjbgmDW 2W3iKOJxqfGFggbUBBI8Gmeiap16MQaYfTlsSmhU= From: Mark Harmstone To: linux-btrfs@vger.kernel.org Cc: Mark Harmstone , Boris Burkov Subject: [PATCH v8 17/17] btrfs: populate fully_remapped_bgs_list on mount Date: Wed, 7 Jan 2026 14:09:17 +0000 Message-ID: <20260107141015.25819-18-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 function btrfs_populate_fully_remapped_bgs_list() which gets called on mount, which looks for fully remapped block groups (i.e. identity_remap_count == 0) which haven't yet had their chunk stripes and device extents removed. This happens when a filesystem is unmounted while async discard has not yet finished, as otherwise the data range occupied by the chunk stripes would be permanently unusable. Signed-off-by: Mark Harmstone Reviewed-by: Boris Burkov --- fs/btrfs/block-group.c | 79 +++++++++++++++++++++++++++++++++++++ fs/btrfs/block-group.h | 2 + fs/btrfs/disk-io.c | 9 +++++ fs/btrfs/free-space-cache.c | 18 +++++++++ fs/btrfs/relocation.c | 4 ++ 5 files changed, 112 insertions(+) diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 47454c22d6f4..1f5101f40b8c 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -4815,6 +4815,11 @@ void btrfs_mark_bg_fully_remapped(struct btrfs_block_group *bg, struct btrfs_fs_info *fs_info = trans->fs_info; if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) { + spin_lock(&bg->lock); + set_bit(BLOCK_GROUP_FLAG_STRIPE_REMOVAL_PENDING, + &bg->runtime_flags); + spin_unlock(&bg->lock); + btrfs_discard_queue_work(&fs_info->discard_ctl, bg); } else { spin_lock(&fs_info->unused_bgs_lock); @@ -4834,3 +4839,77 @@ void btrfs_mark_bg_fully_remapped(struct btrfs_block_group *bg, spin_unlock(&fs_info->unused_bgs_lock); } } + +/* + * Compare the block group and chunk trees, and find any fully-remapped block + * groups which haven't yet had their chunk stripes and device extents removed, + * and put them on the fully_remapped_bgs list so this gets done. + * + * This happens when a block group becomes fully remapped, i.e. its last + * identity mapping is removed, and the volume is unmounted before async + * discard has finished. It's important this gets done as until it is the + * chunk's stripes are dead space. + */ +int btrfs_populate_fully_remapped_bgs_list(struct btrfs_fs_info *fs_info) +{ + struct rb_node *node_bg, *node_chunk; + + node_bg = rb_first_cached(&fs_info->block_group_cache_tree); + node_chunk = rb_first_cached(&fs_info->mapping_tree); + + while (node_bg && node_chunk) { + struct btrfs_block_group *bg; + struct btrfs_chunk_map *map; + + bg = rb_entry(node_bg, struct btrfs_block_group, cache_node); + map = rb_entry(node_chunk, struct btrfs_chunk_map, rb_node); + + ASSERT(bg->start == map->start); + + if (!(bg->flags & BTRFS_BLOCK_GROUP_REMAPPED)) + goto next; + + if (bg->identity_remap_count != 0) + goto next; + + if (map->num_stripes == 0) + goto next; + + spin_lock(&fs_info->unused_bgs_lock); + + if (list_empty(&bg->bg_list)) { + btrfs_get_block_group(bg); + list_add_tail(&bg->bg_list, + &fs_info->fully_remapped_bgs); + } else { + list_move_tail(&bg->bg_list, + &fs_info->fully_remapped_bgs); + } + + spin_unlock(&fs_info->unused_bgs_lock); + + /* + * Ideally we'd want to call btrfs_discard_queue_work() here, + * but it'd do nothing as the discard worker hasn't been + * started yet. + * + * The block group will get added to the discard list when + * btrfs_handle_fully_remapped_bgs() gets called, when we + * commit the first transaction. + */ + if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) { + spin_lock(&bg->lock); + set_bit(BLOCK_GROUP_FLAG_STRIPE_REMOVAL_PENDING, + &bg->runtime_flags); + spin_unlock(&bg->lock); + } + +next: + node_bg = rb_next(node_bg); + node_chunk = rb_next(node_chunk); + } + + ASSERT(!node_bg && !node_chunk); + + return 0; +} diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h index 3117cebf02f5..ccca6ee517a9 100644 --- a/fs/btrfs/block-group.h +++ b/fs/btrfs/block-group.h @@ -94,6 +94,7 @@ enum btrfs_block_group_flags { */ BLOCK_GROUP_FLAG_NEW, BLOCK_GROUP_FLAG_FULLY_REMAPPED, + BLOCK_GROUP_FLAG_STRIPE_REMOVAL_PENDING, }; enum btrfs_caching_type { @@ -416,5 +417,6 @@ int btrfs_use_block_group_size_class(struct btrfs_block_group *bg, bool btrfs_block_group_should_use_size_class(const struct btrfs_block_group *bg); void btrfs_mark_bg_fully_remapped(struct btrfs_block_group *bg, struct btrfs_trans_handle *trans); +int btrfs_populate_fully_remapped_bgs_list(struct btrfs_fs_info *fs_info); #endif /* BTRFS_BLOCK_GROUP_H */ diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index ba500e3bf0d8..0491b799148f 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3613,6 +3613,15 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device goto fail_sysfs; } + if (btrfs_fs_incompat(fs_info, REMAP_TREE)) { + ret = btrfs_populate_fully_remapped_bgs_list(fs_info); + if (ret) { + btrfs_err(fs_info, + "failed to populate fully_remapped_bgs list: %d", ret); + goto fail_sysfs; + } + } + btrfs_zoned_reserve_data_reloc_bg(fs_info); btrfs_free_zone_cache(fs_info); diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index e15fa8567f7c..7f7744a78de2 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -3068,6 +3068,7 @@ bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group) bool ret = true; if (block_group->flags & BTRFS_BLOCK_GROUP_REMAPPED && + !test_bit(BLOCK_GROUP_FLAG_STRIPE_REMOVAL_PENDING, &block_group->runtime_flags) && block_group->identity_remap_count == 0) { return true; } @@ -3849,6 +3850,23 @@ void btrfs_trim_fully_remapped_block_group(struct btrfs_block_group *bg) const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size); u64 end = btrfs_block_group_end(bg); + if (!test_bit(BLOCK_GROUP_FLAG_STRIPE_REMOVAL_PENDING, &bg->runtime_flags)) { + bg->discard_cursor = end; + + if (bg->used == 0) { + spin_lock(&fs_info->unused_bgs_lock); + if (!list_empty(&bg->bg_list)) { + list_del_init(&bg->bg_list); + btrfs_put_block_group(bg); + } + spin_unlock(&fs_info->unused_bgs_lock); + + btrfs_mark_bg_unused(bg); + } + + return; + } + bytes = end - bg->discard_cursor; if (max_discard_size && diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 20cf0f7fd401..c3f1b7828179 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -4785,6 +4785,10 @@ int btrfs_last_identity_remap_gone(struct btrfs_chunk_map *chunk_map, btrfs_remove_bg_from_sinfo(bg); + spin_lock(&bg->lock); + clear_bit(BLOCK_GROUP_FLAG_STRIPE_REMOVAL_PENDING, &bg->runtime_flags); + spin_unlock(&bg->lock); + ret = remove_chunk_stripes(trans, chunk_map, path); if (unlikely(ret)) { btrfs_abort_transaction(trans, ret); -- 2.51.2