This is a note to let you know that I've just added the patch titled
dm table: propagate BDI_CAP_STABLE_WRITES to fix sporadic checksum errors
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-table-propagate-bdi_cap_stable_writes-to-fix-sporadic-checksum-errors.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From eb40c0acdc342b815d4d03ae6abb09e80c0f2988 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@xxxxxxxxx>
Date: Tue, 26 Mar 2019 20:20:58 +0100
Subject: dm table: propagate BDI_CAP_STABLE_WRITES to fix sporadic checksum errors
From: Ilya Dryomov <idryomov@xxxxxxxxx>
commit eb40c0acdc342b815d4d03ae6abb09e80c0f2988 upstream.
Some devices don't use blk_integrity but still want stable pages
because they do their own checksumming. Examples include rbd and iSCSI
when data digests are negotiated. Stacking DM (and thus LVM) on top of
these devices results in sporadic checksum errors.
Set BDI_CAP_STABLE_WRITES if any underlying device has it set.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-table.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1435,6 +1435,36 @@ static bool dm_table_supports_discards(s
return 0;
}
+static int device_requires_stable_pages(struct dm_target *ti,
+ struct dm_dev *dev, sector_t start,
+ sector_t len, void *data)
+{
+ struct request_queue *q = bdev_get_queue(dev->bdev);
+
+ return q && bdi_cap_stable_pages_required(q->backing_dev_info);
+}
+
+/*
+ * If any underlying device requires stable pages, a table must require
+ * them as well. Only targets that support iterate_devices are considered:
+ * don't want error, zero, etc to require stable pages.
+ */
+static bool dm_table_requires_stable_pages(struct dm_table *t)
+{
+ struct dm_target *ti;
+ unsigned i;
+
+ for (i = 0; i < dm_table_get_num_targets(t); i++) {
+ ti = dm_table_get_target(t, i);
+
+ if (ti->type->iterate_devices &&
+ ti->type->iterate_devices(ti, device_requires_stable_pages, NULL))
+ return true;
+ }
+
+ return false;
+}
+
void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
struct queue_limits *limits)
{
@@ -1486,6 +1516,15 @@ void dm_table_set_restrictions(struct dm
queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
/*
+ * Some devices don't use blk_integrity but still want stable pages
+ * because they do their own checksumming.
+ */
+ if (dm_table_requires_stable_pages(t))
+ q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
+ else
+ q->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
+
+ /*
* QUEUE_FLAG_STACKABLE must be set after all queue settings are
* visible to other CPUs because, once the flag is set, incoming bios
* are processed by request-based dm, which refers to the queue
Patches currently in stable-queue which might be from idryomov@xxxxxxxxx are
queue-3.18/dm-table-propagate-bdi_cap_stable_writes-to-fix-sporadic-checksum-errors.patch
