From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 318ED4F5DE4; Tue, 13 Oct 2026 12:08:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893310; cv=none; b=Jv30xPuMRr7nElvKxWchbwVtZdDD+AhIKo+6pL1IPslMN9Ab8EOzQBik0xCKraKDpGFwgHd+A/1L6YVMBDgPA2QfxvIDW+PTsswVBs5V0Wu6E+3+zN20qpAmbYFjPsAPEICLWAWrlgGbu7h9mfwV9i9ZcKLgMcOfm7p/tLdxrDc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893310; c=relaxed/simple; bh=a7zuqYjJQCdZMcvQzfavPKQCiTDgMJltQ0u5o3U0nnA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rj7faCd0c3/7D6GVZLsuAuA2/yjhi2Kdv/ecs/JdTXhpWUlkTTqlVfFRbzT3Rq5OgiuxMubv9qSkX91thnHm3tzI9iya7kxq4g2Q33Qbc7rR/qyxzI64mLn34NY+S1lq5C3K1n89s/DsJOCro+eusEce5sZlf+YjM7VFTZ2NUD0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QdPti+p6; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="QdPti+p6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 813321F000FF; Tue, 13 Oct 2026 12:08:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791893309; bh=w4l2QLaTPji3D2Q+7avGA07+F4M91OSgafabR3rVSDQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QdPti+p6MJvzlfsMKzLif5/o//63ixHG+P+ugmDTQC+wy72qmWdCiPSgM1sRHqR4k Ap6GJLptmTvZ0OoL4f7JgmFz26Z15aM0T3JuJjo9P9SR0sFXIcdPkSXcP5WfEK08k0 Ibrmpw0j3ePrlWeUK0igIjSxA9xZw2W2XvwcTv+A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christoph Hellwig , Qu Wenruo , David Sterba , Sasha Levin Subject: [PATCH 6.18 183/621] btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure() Date: Tue, 13 Oct 2026 13:32:58 +0200 Message-ID: <20261013112925.206045468@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qu Wenruo [ Upstream commit 8ceaad6cd6e7fa5f73b0b2796a2e85d75d37e9f3 ] [BUG] There is a bug report that when btrfs hits ENOSPC error in a critical path, btrfs flips RO (this part is expected, although the ENOSPC bug still needs to be addressed). The problem is after the RO flip, if there is a read repair pending, we can hit the ASSERT() inside btrfs_repair_io_failure() like the following: BTRFS info (device vdc): relocating block group 30408704 flags metadata|raid1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -28) WARNING: fs/btrfs/extent-tree.c:3235 at __btrfs_free_extent.isra.0+0x453/0xfd0, CPU#1: btrfs/383844 Modules linked in: kvm_intel kvm irqbypass [...] ---[ end trace 0000000000000000 ]--- BTRFS info (device vdc state EA): 2 enospc errors during balance BTRFS info (device vdc state EA): balance: ended with status: -30 BTRFS error (device vdc state EA): parent transid verify failed on logical 30556160 mirror 2 wanted 8 found 6 BTRFS error (device vdc state EA): bdev /dev/nvme0n1 errs: wr 0, rd 0, flush 0, corrupt 10, gen 0 [...] assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 ------------[ cut here ]------------ assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 kernel BUG at fs/btrfs/bio.c:938! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 868 Comm: kworker/u8:13 Tainted: G W N 6.19.0-rc6+ #4788 PREEMPT(full) Tainted: [W]=WARN, [N]=TEST Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Workqueue: btrfs-endio simple_end_io_work RIP: 0010:btrfs_repair_io_failure.cold+0xb2/0x120 RSP: 0000:ffffc90001d2bcf0 EFLAGS: 00010246 RAX: 0000000000000051 RBX: 0000000000001000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8305cf42 RDI: 00000000ffffffff RBP: 0000000000000002 R08: 00000000fffeffff R09: ffffffff837fa988 R10: ffffffff8327a9e0 R11: 6f69747265737361 R12: ffff88813018d310 R13: ffff888168b8a000 R14: ffffc90001d2bd90 R15: ffff88810a169000 FS: 0000000000000000(0000) GS:ffff8885e752c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 ------------[ cut here ]------------ [CAUSE] The cause of -ENOSPC error during the test case btrfs/124 is still unknown, although it's known that we still have cases where metadata can be over-committed but can not be fulfilled correctly, thus if we hit such ENOSPC error inside a critical path, we have no choice but abort the current transaction. This will mark the fs read-only. The problem is inside the btrfs_repair_io_failure() path that we require the fs not to be mount read-only. This is normally fine, but if we are doing a read-repair meanwhile the fs flips RO due to a critical error, we can enter btrfs_repair_io_failure() with super block set to read-only, thus triggering the above crash. [FIX] Just replace the ASSERT() with a proper return if the fs is already read-only. Reported-by: Christoph Hellwig Link: https://lore.kernel.org/linux-btrfs/20260126045555.GB31641@lst.de/ Tested-by: Christoph Hellwig Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/bio.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c index afe022a3b8fc3..d13a143149225 100644 --- a/fs/btrfs/bio.c +++ b/fs/btrfs/bio.c @@ -902,7 +902,6 @@ int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 fileoff, struct bio *bio = NULL; int ret = 0; - ASSERT(!(fs_info->sb->s_flags & SB_RDONLY)); BUG_ON(!mirror_num); /* Basic alignment checks. */ @@ -914,6 +913,13 @@ int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 fileoff, ASSERT(step <= length); ASSERT(is_power_of_2(step)); + /* + * The fs either mounted RO or hit critical errors, no need + * to continue repairing. + */ + if (unlikely(sb_rdonly(fs_info->sb))) + return 0; + if (btrfs_repair_one_zone(fs_info, logical)) return 0; -- 2.53.0