From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A515A3C1967 for ; Wed, 25 Feb 2026 13:47:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772027266; cv=none; b=i/Hoz/Z/OXju7N+jzbfmcgMv2KnRtnOLbpHdcPTDYU/7P9hwzfyBMGKh+uLI3S+OlsaW40qmzlLCKaWPuQZXUlMRDtHjXCQDMvDtaL2XLtwu5OKr7oBKMygKQibBE5nX3L5a60ABGZ8EdHraeOK6PHJLb1LVnr0aN4Svah7jgOo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772027266; c=relaxed/simple; bh=16YVwGmRyCsDl532QjpJpz0BJTf40SoA/nMDbQ3EoQA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jdXtuAOIFahWWLkNSCS7VWNzR71dw9Xzey3OxrE+choZSaETOYFWuc3gff0tEuvxlJsiqPhC4feTo255CL/IAdelsx4lxs2Jpzdc724Hdd8FpCLzm83gqFJb7mhstXmEaZxTCo/40ekvc4OkbRnap4RPDSGxwNcOVp3XRzVbo1A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eMxA+i+a; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eMxA+i+a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9C4BC116D0; Wed, 25 Feb 2026 13:47:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772027266; bh=16YVwGmRyCsDl532QjpJpz0BJTf40SoA/nMDbQ3EoQA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eMxA+i+aQVtgsJ/RPI4lcz/L8aWyubxR37c2dxZ7iViPsCYgQewlkRi2oIte/D/I0 v4uPI64Wn9oVgOW9jUX2sYcpSoZ22raIU509pv+/8G1FFCap3CwicUpLFOndR0fby5 8x8BWdpqwvmCABr/3Nu/FmQKxrCS2mfV3J9y5O58e6tdz/hTciH9ge1bGQl8tiY88X 9k2HsRn98QPQ+1g9mQQwc9royAYtBlP4gHatvv9BmY2RtWE7dv5g2SmQI7gPt4c5Et 5QcCGCdyS64ETkq0S6dgoqhQ6IQMOymqjPR04hrahoMnR8YRi426SgmkBrXzk0bgch fiC1vUB8baWTQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Brian Foster , Baokun Li , Theodore Ts'o , stable@kernel.org, Sasha Levin Subject: [PATCH 6.6.y] ext4: fix dirtyclusters double decrement on fs shutdown Date: Wed, 25 Feb 2026 08:47:44 -0500 Message-ID: <20260225134744.311174-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2026022419-resonate-expanse-908a@gregkh> References: <2026022419-resonate-expanse-908a@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Brian Foster [ Upstream commit 94a8cea54cd935c54fa2fba70354757c0fc245e3 ] 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 Reviewed-by: Baokun Li Link: https://patch.msgid.link/20260113171905.118284-1-bfoster@redhat.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org [ Drop mballoc-test changes ] Signed-off-by: Sasha Levin --- 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 5ba161bd66a3e..4a71a92ce12aa 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3998,8 +3998,7 @@ void ext4_exit_mballoc(void) * 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 buffer_head *bitmap_bh = NULL; struct ext4_group_desc *gdp; @@ -4085,13 +4084,6 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, ext4_unlock_group(sb, ac->ac_b_ex.fe_group); 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); if (sbi->s_log_groups_per_flex) { ext4_group_t flex_group = ext4_flex_group(sbi, @@ -6264,7 +6256,7 @@ 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; @@ -6295,12 +6287,9 @@ 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 any reserved blocks */ + if (reserv_clstrs) + percpu_counter_sub(&sbi->s_dirtyclusters_counter, reserv_clstrs); trace_ext4_allocate_blocks(ar, (unsigned long long)block); -- 2.51.0