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Wed, 25 Mar 2026 12:54:23 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=harmstone.com; s=mail; t=1774443263; bh=AZIXN+Y73PIl3ih35VBn/ri/kEUiHrnMRAWg1yXfxg4=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=kEEXWmbE+xee+TMQ+EOlQQ7m2ym4H9wNRHQ2tzxiJ5HaiaP/eLkLd1oqXN0NUKgeV wJkze5K+5A7w9j5gXztb/Rw+fGM9eMCbTRz5A45wbBKK6b0TxChW6hxazun09LzY2Z opVGShnEGQyKcga2cBZuWss0L8LVpTpCK/nc678k= Message-ID: <95ff3c8f-4932-4fe6-b46e-dcdbc876968d@harmstone.com> Date: Wed, 25 Mar 2026 12:54:23 +0000 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Subject: Re: [PATCH] btrfs: add remap-tree checks to check_block_group_item() To: dsterba@suse.cz Cc: linux-btrfs@vger.kernel.org References: <20260323172619.152258-1-mark@harmstone.com> <20260323194348.GS5735@twin.jikos.cz> Content-Language: en-US From: Mark Harmstone Autocrypt: addr=mark@harmstone.com; keydata= xsBNBFp/GMsBCACtFsuHZqHWpHtHuFkNZhMpiZMChyou4X8Ueur3XyF8KM2j6TKkZ5M/72qT EycEM0iU1TYVN/Rb39gBGtRclLFVY1bx4i+aUCzh/4naRxqHgzM2SeeLWHD0qva0gIwjvoRs FP333bWrFKPh5xUmmSXBtBCVqrW+LYX4404tDKUf5wUQ9bQd2ItFRM2mU/l6TUHVY2iMql6I s94Bz5/Zh4BVvs64CbgdyYyQuI4r2tk/Z9Z8M4IjEzQsjSOfArEmb4nj27R3GOauZTO2aKlM 8821rvBjcsMk6iE/NV4SPsfCZ1jvL2UC3CnWYshsGGnfd8m2v0aLFSHZlNd+vedQOTgnABEB AAHNI01hcmsgSGFybXN0b25lIDxtYXJrQGhhcm1zdG9uZS5jb20+wsCRBBMBCAA7AhsvBQsJ CAcCBhUICQoLAgQWAgMBAh4BAheAFiEEG2JgKYgV0WRwIJAqbKyhHeAWK+0FAmRQOkICGQEA CgkQbKyhHeAWK+22wgf/dBOJ0pHdkDi5fNmWynlxteBsy3VCo0qC25DQzGItL1vEY95EV4uX re3+6eVRBy9gCKHBdFWk/rtLWKceWVZ86XfTMHgy+ZnIUkrD3XZa3oIV6+bzHgQ15rXXckiE A5N+6JeY/7hAQpSh/nOqqkNMmRkHAZ1ZA/8KzQITe1AEULOn+DphERBFD5S/EURvC8jJ5hEr lQj8Tt5BvA57sLNBmQCE19+IGFmq36EWRCRJuH0RU05p/MXPTZB78UN/oGT69UAIJAEzUzVe sN3jiXuUWBDvZz701dubdq3dEdwyrCiP+dmlvQcxVQqbGnqrVARsGCyhueRLnN7SCY1s5OHK ls7ATQRafxjLAQgAvkcSlqYuzsqLwPzuzoMzIiAwfvEW3AnZxmZn9bQ+ashB9WnkAy2FZCiI /BPwiiUjqgloaVS2dIrVFAYbynqSbjqhki+uwMliz7/jEporTDmxx7VGzdbcKSCe6rkE/72o 6t7KG0r55cmWnkdOWQ965aRnRAFY7Zzd+WLqlzeoseYsNj36RMaqNR7aL7x+kDWnwbw+jgiX tgNBcnKtqmJc04z/sQTa+sUX53syht1Iv4wkATN1W+ZvQySxHNXK1r4NkcDA9ZyFA3NeeIE6 ejiO7RyC0llKXk78t0VQPdGS6HspVhYGJJt21c5vwSzIeZaneKULaxXGwzgYFTroHD9n+QAR AQABwsGsBBgBCAAgFiEEG2JgKYgV0WRwIJAqbKyhHeAWK+0FAlp/GMsCGy4BQAkQbKyhHeAW K+3AdCAEGQEIAB0WIQR6bEAu0hwk2Q9ibSlt5UHXRQtUiwUCWn8YywAKCRBt5UHXRQtUiwdE B/9OpyjmrshY40kwpmPwUfode2Azufd3QRdthnNPAY8Tv9erwsMS3sMh+M9EP+iYJh+AIRO7 fDN/u0AWIqZhHFzCndqZp8JRYULnspXSKPmVSVRIagylKew406XcAVFpEjloUtDhziBN7ykk srAMoLASaBHZpAfp8UAGDrr8Fx1on46rDxsWbh1K1h4LEmkkVooDELjsbN9jvxr8ym8Bkt54 FcpypTOd8jkt/lJRvnKXoL3rZ83HFiUFtp/ZkveZKi53ANUaqy5/U5v0Q0Ppz9ujcRA9I/V3 B66DKMg1UjiigJG6espeIPjXjw0n9BCa9jqGICyJTIZhnbEs1yEpsM87eUIH/0UFLv0b8IZe pL/3QfiFoYSqMEAwCVDFkCt4uUVFZczKTDXTFkwm7zflvRHdy5QyVFDWMyGnTN+Bq48Gwn1M uRT/Sg37LIjAUmKRJPDkVr/DQDbyL6rTvNbA3hTBu392v0CXFsvpgRNYaT8oz7DDBUUWj2Ny 6bZCBtwr/O+CwVVqWRzKDQgVo4t1xk2ts1F0R1uHHLsX7mIgfXBYdo/y4UgFBAJH5NYUcBR+ QQcOgUUZeF2MC9i0oUaHJOIuuN2q+m9eMpnJdxVKAUQcZxDDvNjZwZh+ejsgG4Ejd2XR/T0y XFoR/dLFIhf2zxRylN1xq27M9P2t1xfQFocuYToPsVk= In-Reply-To: <20260323194348.GS5735@twin.jikos.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 23/03/2026 7.43 pm, David Sterba wrote: > On Mon, Mar 23, 2026 at 05:26:13PM +0000, Mark Harmstone wrote: >> Add some write-time checks for block group items relating to the remap >> tree. >> >> Here we're checking: >> * That the REMAPPED or METADATA_REMAP flags aren't set unless the >> REMAP_TREE incompat flag is also set >> * That `remap_bytes` isn't more than the size of the block group >> * That `identity_remap_count` isn't more than the number of sectors in >> the block group >> >> Signed-off-by: Mark Harmstone >> --- >> fs/btrfs/tree-checker.c | 42 +++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 42 insertions(+) >> >> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c >> index 495d1dd61e66c2..cad23f3fadfd34 100644 >> --- a/fs/btrfs/tree-checker.c >> +++ b/fs/btrfs/tree-checker.c >> @@ -777,6 +777,48 @@ static int check_block_group_item(struct extent_buffer *leaf, >> BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA); >> return -EUCLEAN; >> } >> + >> + if (unlikely(!btrfs_fs_incompat(fs_info, REMAP_TREE) && >> + type == BTRFS_BLOCK_GROUP_METADATA_REMAP)) { >> + block_group_err(leaf, slot, >> +"invalid type, METADATA_REMAP set but REMAP_TREE incompat flag not set"); >> + return -EUCLEAN; >> + } >> + >> + if (unlikely(!btrfs_fs_incompat(fs_info, REMAP_TREE) && >> + flags & BTRFS_BLOCK_GROUP_REMAPPED)) { >> + block_group_err(leaf, slot, >> +"invalid flags, REMAPPED set but REMAP_TREE incompat flag not set"); >> + return -EUCLEAN; >> + } >> + >> + if (item_size == sizeof(struct btrfs_block_group_item_v2)) { >> + struct btrfs_block_group_item_v2 *bgi2; >> + u64 remap_bytes; >> + u32 identity_remap_count; >> + >> + bgi2 = btrfs_item_ptr(leaf, slot, struct btrfs_block_group_item_v2); >> + >> + remap_bytes = btrfs_block_group_v2_remap_bytes(leaf, bgi2); >> + >> + if (unlikely(remap_bytes > key->offset)) { >> + block_group_err(leaf, slot, >> + "invalid remap_bytes, have %llu expect [0, %llu]", >> + remap_bytes, key->offset); >> + return -EUCLEAN; >> + } >> + >> + identity_remap_count = btrfs_block_group_v2_identity_remap_count(leaf, bgi2); >> + if (unlikely((u64)identity_remap_count > >> + key->offset / fs_info->sectorsize)) { > > 64bit / 32bit may not work on all arches, we have the sectorize_bits to > avoid it. Annoying. Thank you, I've sent another patch. >> + block_group_err(leaf, slot, >> + "invalid identity_remap_count, have %u expect [0, %llu]", >> + identity_remap_count, >> + key->offset / fs_info->sectorsize); >> + return -EUCLEAN; >> + } >> + } >> + >> return 0; >> } >> >> -- >> 2.52.0 >>