From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794049283; b=myvm4nXQx0c5pTMsz/7SsKzQkYPwjzCLnWlt7hP5O5M+gG4xs4Szyn82RhWmLUI05uwb iWGQxEMX0njVbEhSil6eHJfdfRKu9ac9enA7oWISRjagj4jZZQrcIGoaALGbW4oOb/nRq Z8mCds4vleEoso6XPHrZUaX8ymXzwBY6WFtujW8CcD7HNctv41JhLNgCiY1MPQ4RV7KrL UUimZ56AgTRb2KVAQmEQv9FWU5rqBua28hbPed7ex0kvzsuKFU7jRGVcbHNYh7oaWacO2 T5LGIJi9dXGG6trPZOj4rRTuvoaOfSwfSxIgdir+1gw8NSmfFspDi9stzqmE4Wm2IZQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794049283; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=ZG02YtCWlItD3n2tyHZvuB73ie0W4MTagLAouTG0FXA=; b=UErC9zihAJv7Cilj1Y3MHDhdF3QbLovTwvIxeEaQcJrTHkfNSGPczB8+ZNq7BK5Yz5Os /6ChC0nKi9klDH6p3IUNSv+tlaRjpu/nVqGkkScuXK/0t8kGs82deBEj5BH0CAoj/bANC erALKSKBXGHVx6/3G/rpQOf+QC7LMi+uIPJgpUKAErigeyl+kcE2hQdhD87RSSilKPwLO 8Csj6lN9VpCGVuUlpFCS69KPXMozTJFY2+gsBryZ/RXk3xbkYzQOyZuEG0W0zx+LgnR6C dnNPnRQz07K+MfpB1o8WjyjSSwh+2h7VhpHzo1ChTVVXTc54eYKkGsm6oTdoqjt+o1A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mjNI2ggk; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D6811606A32C for ; Sat, 7 Nov 2026 11:01:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mjNI2ggk Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A8AB1F0089F; Sat, 7 Nov 2026 11:01:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794049282; bh=ZG02YtCWlItD3n2tyHZvuB73ie0W4MTagLAouTG0FXA=; h=From:To:Cc:Subject:Date; b=mjNI2ggkuTnyeN15GaHxJz5V+LTlG8GJS4mswFOK2Gx98pa94NGZhfGnNaX0+nrOg /WTkifm3W4CpotphekLtDLwJLDNpkcEJz7HlobZNIR4tpt9uQS4soHHzXdvPvlntzM eJMlyVChwU/VXLwfnygyHLZsWzmVtkwl/zAoP+Bp0M+KkbF5D6nxyrXc28OspLvCsg mriLIxKQkNNitzYf2ASuYrHRXxmVdY0pFRrjvV7D1VzdHbGkBF8VUgqTm9h//w2zuO Xrp/Nw/9AvAJO1+mjvTORp+6jExdFcDYSOSLmnBC1ePgR5SResqy/lmvHYwgDqcLE/ pc17yRxPZ95Bg== From: Sasha Levin To: mpatocka@redhat.com Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] dm-writecache: fix REQ_FUA processing" failed to apply to 5.15-stable tree Date: Sat, 7 Nov 2026 06:01:21 -0500 Message-ID: <20261107060120-failed-5.15-c0df022cb0fa@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x c0df022cb0fa2bbee74bd9b90c66790bcd4e3050 # git commit -s git send-email --to '' --in-reply-to '20261107060120-failed-5.15-c0df022cb0fa@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From c0df022cb0fa2bbee74bd9b90c66790bcd4e3050 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Wed, 30 Sep 2026 21:43:26 +0200 Subject: [PATCH] dm-writecache: fix REQ_FUA processing REQ_FUA did not flush metadata in SSD mode, this commit fixes it. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Fixes: c1005322ff02 ("dm writecache: handle REQ_FUA") Assisted-by: Claude:claude-opus-5 Assisted-by: Codex:gpt-6-sol --- drivers/md/dm-writecache.c | 45 +++++++++++++++++++++++++++++--------- 1 file changed, 35 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index a38780a7b1be9..6f977fb8c9397 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -188,6 +188,7 @@ struct dm_writecache { struct task_struct *endio_thread; struct task_struct *flush_thread; + spinlock_t flush_list_lock; struct bio_list flush_list; struct dm_kcopyd_client *dm_kcopyd; @@ -1289,9 +1290,11 @@ static int writecache_flush_thread(void *data) struct bio *bio; wc_lock(wc); + spin_lock_irq(&wc->flush_list_lock); bio = bio_list_pop(&wc->flush_list); if (!bio) { set_current_state(TASK_INTERRUPTIBLE); + spin_unlock_irq(&wc->flush_list_lock); wc_unlock(wc); if (unlikely(kthread_should_stop())) { @@ -1302,6 +1305,7 @@ static int writecache_flush_thread(void *data) schedule(); continue; } + spin_unlock_irq(&wc->flush_list_lock); if (bio_op(bio) == REQ_OP_DISCARD) { writecache_discard(wc, bio->bi_iter.bi_sector, @@ -1323,9 +1327,12 @@ static int writecache_flush_thread(void *data) static void writecache_offload_bio(struct dm_writecache *wc, struct bio *bio) { + unsigned long flags; + spin_lock_irqsave(&wc->flush_list_lock, flags); if (bio_list_empty(&wc->flush_list)) wake_up_process(wc->flush_thread); bio_list_add(&wc->flush_list, bio); + spin_unlock_irqrestore(&wc->flush_list_lock, flags); } enum wc_map_op { @@ -1437,6 +1444,8 @@ static void writecache_bio_copy_ssd(struct dm_writecache *wc, struct bio *bio, static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio *bio) { struct wc_entry *e; + enum wc_map_op ret = WC_MAP_SUBMIT; + bool need_flush = false; do { bool found_entry = false; @@ -1473,7 +1482,8 @@ static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio writecache_map_remap_origin(wc, bio, e); wc->stats.writes_around += bio->bi_iter.bi_size >> wc->block_size_bits; wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits; - return WC_MAP_REMAP_ORIGIN; + ret = WC_MAP_REMAP_ORIGIN; + goto flush_pmem_and_ret; } wc->stats.writes_blocked_on_freelist++; writecache_wait_on_freelist(wc); @@ -1487,21 +1497,25 @@ static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio if (WC_MODE_PMEM(wc)) { bio_copy_block(wc, bio, memory_data(wc, e)); wc->stats.writes++; + need_flush = true; } else { writecache_bio_copy_ssd(wc, bio, e, search_used); return WC_MAP_REMAP; } } while (bio->bi_iter.bi_size); - if (unlikely(bio->bi_opf & REQ_FUA || wc->uncommitted_blocks >= wc->autocommit_blocks)) { - writecache_flush(wc); - if (writecache_has_error(wc)) - bio->bi_status = BLK_STS_IOERR; - } else { - writecache_schedule_autocommit(wc); +flush_pmem_and_ret: + if (need_flush) { + if (unlikely(bio->bi_opf & REQ_FUA || wc->uncommitted_blocks >= wc->autocommit_blocks)) { + writecache_flush(wc); + if (writecache_has_error(wc)) + ret = WC_MAP_ERROR; + } else { + writecache_schedule_autocommit(wc); + } } - return WC_MAP_SUBMIT; + return ret; } static enum wc_map_op writecache_map_flush(struct dm_writecache *wc, struct bio *bio) @@ -1591,7 +1605,10 @@ static int writecache_map(struct dm_target *ti, struct bio *bio) case WC_MAP_REMAP: /* make sure that writecache_end_io decrements bio_in_progress: */ - bio->bi_private = (void *)1; + if (unlikely(bio->bi_opf & REQ_FUA) && bio_op(bio) == REQ_OP_WRITE) + bio->bi_private = (void *)3; + else + bio->bi_private = (void *)1; atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]); wc_unlock(wc); return DM_MAPIO_REMAPPED; @@ -1621,12 +1638,19 @@ static int writecache_end_io(struct dm_target *ti, struct bio *bio, blk_status_t { struct dm_writecache *wc = ti->private; - if (bio->bi_private == (void *)1) { + if (bio->bi_private == (void *)1 || bio->bi_private == (void *)3) { int dir = bio_data_dir(bio); + bool fua = bio->bi_private == (void *)3; if (atomic_dec_and_test(&wc->bio_in_progress[dir])) if (unlikely(waitqueue_active(&wc->bio_in_progress_wait[dir]))) wake_up(&wc->bio_in_progress_wait[dir]); + + if (fua && likely(*status == BLK_STS_OK)) { + bio->bi_private = NULL; + writecache_offload_bio(wc, bio); + return DM_ENDIO_INCOMPLETE; + } } else if (bio->bi_private == (void *)2) { dm_iot_io_end(&wc->iot, 1); } @@ -2519,6 +2543,7 @@ static int writecache_ctr(struct dm_target *ti, unsigned int argc, char **argv) wc->memory_map_size -= (uint64_t)wc->start_sector << SECTOR_SHIFT; + spin_lock_init(&wc->flush_list_lock); bio_list_init(&wc->flush_list); wc->flush_thread = kthread_run(writecache_flush_thread, wc, "dm_writecache_flush"); if (IS_ERR(wc->flush_thread)) { -- 2.53.0