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 A0B89311C01 for ; Mon, 11 Aug 2025 16:59:20 +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=1754931566; cv=none; b=NG7Lcw4nYRobGwENc6td7Nr3fkUVAe4C1elLMcBdjYDoxZ6s/rx+otjp6ufyiiGj1cCXZmK5kgEw7phwCygbzRtG6ONiZNaB6xCDbsN3PPKCvXrxtq17cEGzacQ2+pDNOaaSqheDkgeZ/mATE56diH9lwfvz9W3GtNGIRGjIpLo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754931566; c=relaxed/simple; bh=KfktSIZWRL7T+wNdocOLB9vpIRptYM0R/9LGtRN+8bs=; h=Message-ID:Date:Mime-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Mw4rRYoE6kD3OGrsgG39Armzi7mP8ItJdk3236XkJUkHsGDxS9MHSH77bmkhfdFsIb8tAuHnabMdatugLpLYZbLu/A/HAmjxywxg5owfxYGYsVI42BhmTqL1eCCEoY+uovj83DBKZkaquPqFzTN1nr+g8h9I+R5UowiEPDV/Gc4= 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=VAr0ISrQ; 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="VAr0ISrQ" Received: from [IPV6:2a02:8012:8cf0:0:ce28:aaff:fe0d:6db2] (beren.burntcomma.com [IPv6:2a02:8012:8cf0:0:ce28:aaff:fe0d:6db2]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "hellas", Issuer "burntcomma.com" (verified OK)) by mail.burntcomma.com (Postfix) with ESMTPS id 65B382A65FD; Mon, 11 Aug 2025 17:59:17 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=harmstone.com; s=mail; t=1754931557; bh=tAq0E0hPnycYSxecmc2bBnJr33xP+ULJ6q2wE8+QABo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=VAr0ISrQlXFC7x+KHnTuE239AujL1IQ8fwMAgzUBPGFp9C0xwpj5hSuwW0vWZhN45 GnARUZRyF4ixToVAdMweBAONvA09BzraF/9BoXDhWO1Bamcx7WaVixmpib0kvN/Lnz Ic+BKEcuBH1n6tHe09r5N2oj3v7f0/5ORiuX0E+o= Message-ID: Date: Mon, 11 Aug 2025 17:59:17 +0100 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Subject: Re: [PATCH 09/12] btrfs: handle deletions from remapped block group To: Boris Burkov Cc: linux-btrfs@vger.kernel.org References: <20250605162345.2561026-1-maharmstone@fb.com> <20250605162345.2561026-10-maharmstone@fb.com> <20250613234250.GG3621880@zen.localdomain> 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: <20250613234250.GG3621880@zen.localdomain> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 14/06/2025 12.42 am, Boris Burkov wrote: ... snip ... >> @@ -3002,10 +3005,22 @@ static int do_free_extent_accounting(struct btrfs_trans_handle *trans, >> return ret; >> } >> >> - ret = add_to_free_space_tree(trans, bytenr, num_bytes); >> - if (ret) { >> - btrfs_abort_transaction(trans, ret); >> - return ret; >> + if (btrfs_fs_incompat(trans->fs_info, REMAP_TREE)) { >> + bg = btrfs_lookup_block_group(trans->fs_info, bytenr); >> + bg_is_remapped = bg->flags & BTRFS_BLOCK_GROUP_REMAPPED; > > As mentioned in the patch that sets the flag, this feels quite > susceptible to races. I don't have a particular one in mind, it just > feels off to set and rely on this flag to decide what work to do without > some kind of explicit synchronization plan. I thought this was safe, but I think you're right. btrfs_remove_extent_from_remap_tree() ought to return a flag saying whether it touched the FST or not, rather than leaving us to racily guess here.