From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 BACC02236E8 for ; Mon, 12 Jan 2026 14:36:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768228621; cv=none; b=IJ5ILDXaBxlykhFvu5ImHogZBuS1HGRcPbmB42+TFjKfL75unUoN/aUZLm8Ml2d+BTOmTzEmDK/I4RLhJdehLKDTrgS4Ggv7YuzRp0MeFbD8Yg4xjrheiVdCPYd2pJo0K7E/LEHgxnEIL871BxLDgfpP5Tx4aif8Otkmmg8SvMw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768228621; c=relaxed/simple; bh=NOXNpr+veNZ3w+W1EaQej6dMqv7vo7eYUDi1UM2fuSQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=GywL25ont9IVlveSCqq7LSmdhtrTpCGNnJ0NlQGG2cm6ZNrF41RN3v3omQ+ZVYeHmnezYPGW6CkIX6eNMoXAyLwaqrYBu6kMwN9MWOvwcGN+abLdcarUSw9TwkSyzGaB5BNNhy4vpxEidSt3TIgUtjNlwuHmj6k0g3GJXo3qxfo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=BhA6XUvC; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BhA6XUvC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1768228618; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=8fyZO6SMIkSovJJo1An6UJRIOobMaKu0KJq1LKoziaw=; b=BhA6XUvCHjQ/pMPBUEYqgtw5ibn3MXrYgCq6O9DQTvh5DdEMV4m15cYcajPBQnhoNO9aRJ mv2IJq67fUD+xal8PTC2XcvOS9PzhPbXbgkk8WRVkU9Cl7ptjvJzIWuP0tiA82urF+KuWS KGnUgNxB6hFIYfCN9uO5H10AR3jrzMU= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-553-u-7qApM1OY6PfBu2oSbGJg-1; Mon, 12 Jan 2026 09:36:54 -0500 X-MC-Unique: u-7qApM1OY6PfBu2oSbGJg-1 X-Mimecast-MFC-AGG-ID: u-7qApM1OY6PfBu2oSbGJg_1768228613 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 79DA51956046; Mon, 12 Jan 2026 14:36:53 +0000 (UTC) Received: from bfoster.redhat.com (unknown [10.22.80.146]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C9A281800665; Mon, 12 Jan 2026 14:36:52 +0000 (UTC) From: Brian Foster To: linux-ext4@vger.kernel.org Cc: Baokun Li Subject: [PATCH v2] ext4: fix dirtyclusters double decrement on fs shutdown Date: Mon, 12 Jan 2026 09:36:52 -0500 Message-ID: <20260112143652.8085-1-bfoster@redhat.com> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 fstests test generic/388 occasionally reproduces a warning in ext4_put_super() associated with the dirty clusters count: WARNING: CPU: 7 PID: 76064 at fs/ext4/super.c:1324 ext4_put_super+0x48c/0x590 [ext4] Tracing the failure shows that the warning fires due to an s_dirtyclusters_counter value of -1. IOW, this appears to be a spurious decrement as opposed to some sort of leak. Further tracing of the dirty cluster count deltas and an LLM scan of the resulting output identified the cause as a double decrement in the error path between ext4_mb_mark_diskspace_used() and the caller ext4_mb_new_blocks(). First, note that generic/388 is a shutdown vs. fsstress test and so produces a random set of operations and shutdown injections. In the problematic case, the shutdown triggers an error return from the ext4_handle_dirty_metadata() call(s) made from ext4_mb_mark_context(). The changed value is non-zero at this point, so ext4_mb_mark_diskspace_used() does not exit after the error bubbles up from ext4_mb_mark_context(). Instead, the former decrements both cluster counters and returns the error up to ext4_mb_new_blocks(). The latter falls into the !ar->len out path which decrements the dirty clusters counter a second time, creating the inconsistency. To avoid this problem and simplify ownership of the cluster reservation in this codepath, lift the counter reduction to a single place in the caller. This makes it more clear that ext4_mb_new_blocks() is responsible for acquiring cluster reservation (via ext4_claim_free_clusters()) in the !delalloc case as well as releasing it, regardless of whether it ends up consumed or returned due to failure. Fixes: 0087d9fb3f29 ("ext4: Fix s_dirty_blocks_counter if block allocation failed with nodelalloc") Signed-off-by: Brian Foster --- v2: - Condense counter update logic instead of modifying return flow. - Added Fixes: tag. v1: https://lore.kernel.org/linux-ext4/20251212154735.512651-1-bfoster@redhat.com/ fs/ext4/mballoc.c | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 56d50fd3310b..b31d7ddc52a9 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4185,8 +4185,7 @@ ext4_mb_mark_context(handle_t *handle, struct super_block *sb, bool state, * Returns 0 if success or error code */ static noinline_for_stack int -ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, - handle_t *handle, unsigned int reserv_clstrs) +ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, handle_t *handle) { struct ext4_group_desc *gdp; struct ext4_sb_info *sbi; @@ -4241,13 +4240,6 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, BUG_ON(changed != ac->ac_b_ex.fe_len); #endif percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len); - /* - * Now reduce the dirty block count also. Should not go negative - */ - if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED)) - /* release all the reserved blocks if non delalloc */ - percpu_counter_sub(&sbi->s_dirtyclusters_counter, - reserv_clstrs); return err; } @@ -6332,7 +6324,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, ext4_mb_pa_put_free(ac); } if (likely(ac->ac_status == AC_STATUS_FOUND)) { - *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs); + *errp = ext4_mb_mark_diskspace_used(ac, handle); if (*errp) { ext4_discard_allocated_blocks(ac); goto errout; @@ -6363,12 +6355,9 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, out: if (inquota && ar->len < inquota) dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len)); - if (!ar->len) { - if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) - /* release all the reserved blocks if non delalloc */ - percpu_counter_sub(&sbi->s_dirtyclusters_counter, - reserv_clstrs); - } + /* release all the reserved blocks if non delalloc */ + if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) + percpu_counter_sub(&sbi->s_dirtyclusters_counter, reserv_clstrs); trace_ext4_allocate_blocks(ar, (unsigned long long)block); -- 2.52.0