virtio_blk: set the zone write granularitygrafted

virtblk_read_zoned_limits() reads the write granularity that the device
reports in virtio_blk_zoned_characteristics and assigns it to the
physical block size and to io_min, but never to the limit that is named
after it. queue_limits.zone_write_granularity is left at zero, so
blk_validate_zoned_limits() raises it to the logical block size:

	if (lim->zone_write_granularity < lim->logical_block_size)
		lim->zone_write_granularity = lim->logical_block_size;

A device that reports a granularity coarser than its logical block size,
which is what the field exists to express, therefore has it silently
reduced. A 512e host managed disk passed through to a guest reports a
logical block size of 512 and a write granularity of 4096, and the guest
ends up with a zone write granularity of 512.

bio_split_alignment() returns lim->zone_write_granularity if it is non-zero
and bio_split_io_at() may split a bio with as per bio_split_alignment().
This can real to the write getting rejected by the host drive, as the write
is not aligned to the physical block size.

zonefs also takes its block size from bdev_zone_write_granularity(), so it
would incorrectly use 512 on a disk that requires 4096.

sd_zbc_read_zones() sets the limit from the physical block size for the
same reason. NVMe ZNS and null_blk leave it unset, but the fallback
gives the right answer for them, as their write granularity is the
logical block size. virtio carries a separate value that may exceed it.

Set the zone write granularity from the value that the device reports.

Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices")
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://patch.msgid.link/20260918140641.2031075-2-cassel@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 260 insertions, 0 deletions

diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c
new file mode 100644
index 000000000..01461a746
--- /dev/null
+++ b/fs/netfs/objects.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Object lifetime handling and tracing.
+ *
+ * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/slab.h>
+#include <linux/mempool.h>
+#include "internal.h"
+
+static void netfs_free_request(struct work_struct *work);
+
+/*
+ * Allocate an I/O request and initialise it.
+ */
+struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
+					     struct file *file,
+					     loff_t start, size_t len,
+					     enum netfs_io_origin origin)
+{
+	static atomic_t debug_ids;
+	struct inode *inode = file ? file_inode(file) : mapping->host;
+	struct netfs_inode *ctx = netfs_inode(inode);
+	struct netfs_io_request *rreq;
+	mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
+	struct kmem_cache *cache = mempool->pool_data;
+	gfp_t gfp = GFP_KERNEL;
+	int ret;
+
+	/* Writeback is part of memory reclaim and must not fail due to ENOMEM. */
+	if (origin == NETFS_WRITEBACK || origin == NETFS_WRITEBACK_SINGLE) {
+		gfp = GFP_NOFS; /* Allows use of mempools. */
+
+		rreq = mempool_alloc(mempool, gfp);
+	} else {
+		rreq = mempool->alloc(gfp, mempool->pool_data);
+		if (!rreq)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	memset(rreq, 0, kmem_cache_size(cache));
+	INIT_WORK(&rreq->cleanup_work, netfs_free_request);
+	rreq->gfp	= gfp;
+	rreq->start	= start;
+	rreq->len	= len;
+	rreq->origin	= origin;
+	rreq->netfs_ops	= ctx->ops;
+	rreq->mapping	= mapping;
+	rreq->inode	= inode;
+	rreq->i_size	= i_size_read(inode);
+	rreq->debug_id	= atomic_inc_return(&debug_ids);
+	rreq->wsize	= INT_MAX;
+	rreq->io_streams[0].sreq_max_len = ULONG_MAX;
+	rreq->io_streams[0].sreq_max_segs = 0;
+	spin_lock_init(&rreq->lock);
+	INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);
+	INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);
+	init_waitqueue_head(&rreq->waitq);
+	refcount_set(&rreq->ref, 2);
+
+	if (origin == NETFS_READAHEAD ||
+	    origin == NETFS_READPAGE ||
+	    origin == NETFS_READ_GAPS ||
+	    origin == NETFS_READ_SINGLE ||
+	    origin == NETFS_READ_FOR_WRITE ||
+	    origin == NETFS_UNBUFFERED_READ ||
+	    origin == NETFS_DIO_READ) {
+		INIT_WORK(&rreq->work, netfs_read_collection_worker);
+		rreq->io_streams[0].avail = true;
+	} else {
+		INIT_WORK(&rreq->work, netfs_write_collection_worker);
+	}
+
+	__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
+	if (rreq->netfs_ops->init_request) {
+		ret = rreq->netfs_ops->init_request(rreq, file);
+		if (ret < 0) {
+			mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
+			return ERR_PTR(ret);
+		}
+	}
+
+	atomic_inc(&ctx->io_count);
+	trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), netfs_rreq_trace_new);
+	netfs_proc_add_rreq(rreq);
+	netfs_stat(&netfs_n_rh_rreq);
+	return rreq;
+}
+
+void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
+{
+	int r;
+
+	__refcount_inc(&rreq->ref, &r);
+	trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
+}
+
+void netfs_clear_subrequests(struct netfs_io_request *rreq)
+{
+	struct netfs_io_subrequest *subreq;
+	struct netfs_io_stream *stream;
+	int s;
+
+	for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
+		stream = &rreq->io_streams[s];
+		while (!list_empty(&stream->subrequests)) {
+			subreq = list_first_entry(&stream->subrequests,
+						  struct netfs_io_subrequest, rreq_link);
+			list_del(&subreq->rreq_link);
+			netfs_put_subrequest(subreq, netfs_sreq_trace_put_clear);
+		}
+	}
+}
+
+static void netfs_free_request_rcu(struct rcu_head *rcu)
+{
+	struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
+
+	mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
+	netfs_stat_d(&netfs_n_rh_rreq);
+}
+
+static void netfs_deinit_request(struct netfs_io_request *rreq)
+{
+	struct netfs_inode *ictx = netfs_inode(rreq->inode);
+	unsigned int i;
+
+	trace_netfs_rreq(rreq, netfs_rreq_trace_free);
+
+	/* Cancel/flush the result collection worker.  That does not carry a
+	 * ref of its own, so we must wait for it somewhere.
+	 */
+	cancel_work_sync(&rreq->work);
+
+	netfs_proc_del_rreq(rreq);
+	netfs_clear_subrequests(rreq);
+	if (rreq->netfs_ops->free_request)
+		rreq->netfs_ops->free_request(rreq);
+	if (rreq->cache_resources.ops)
+		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
+	if (rreq->direct_bv) {
+		for (i = 0; i < rreq->direct_bv_count; i++) {
+			if (rreq->direct_bv[i].bv_page) {
+				if (rreq->direct_bv_unpin)
+					unpin_user_page(rreq->direct_bv[i].bv_page);
+			}
+		}
+		kvfree(rreq->direct_bv);
+	}
+	rolling_buffer_clear(&rreq->buffer);
+
+	if (atomic_dec_and_test(&ictx->io_count))
+		wake_up_var(&ictx->io_count);
+}
+
+static void netfs_free_request(struct work_struct *work)
+{
+	struct netfs_io_request *rreq =
+		container_of(work, struct netfs_io_request, cleanup_work);
+
+	netfs_deinit_request(rreq);
+	call_rcu(&rreq->rcu, netfs_free_request_rcu);
+}
+
+void netfs_put_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
+{
+	unsigned int debug_id;
+	bool dead;
+	int r;
+
+	if (rreq) {
+		debug_id = rreq->debug_id;
+		dead = __refcount_dec_and_test(&rreq->ref, &r);
+		trace_netfs_rreq_ref(debug_id, r - 1, what);
+		if (dead)
+			WARN_ON(!queue_work(system_dfl_wq, &rreq->cleanup_work));
+	}
+}
+
+/*
+ * Free a request (synchronously) that was just allocated but has
+ * failed before it could be submitted.
+ */
+void netfs_put_failed_request(struct netfs_io_request *rreq)
+{
+	int r = refcount_read(&rreq->ref);
+
+	/* new requests have two references (see
+	 * netfs_alloc_request(), and this function is only allowed on
+	 * new request objects
+	 */
+	WARN_ON_ONCE(r != 2);
+
+	trace_netfs_rreq_ref(rreq->debug_id, r, netfs_rreq_trace_put_failed);
+	netfs_free_request(&rreq->cleanup_work);
+}
+
+/*
+ * Allocate and partially initialise an I/O request structure.
+ */
+struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
+{
+	struct netfs_io_subrequest *subreq;
+	mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
+	struct kmem_cache *cache = mempool->pool_data;
+
+	if (rreq->gfp == GFP_KERNEL)
+		subreq = mempool->alloc(rreq->gfp, mempool->pool_data);
+	else
+		subreq = mempool_alloc(mempool, rreq->gfp);
+	if (!subreq)
+		return NULL;
+
+	memset(subreq, 0, kmem_cache_size(cache));
+	INIT_WORK(&subreq->work, NULL);
+	INIT_LIST_HEAD(&subreq->rreq_link);
+	refcount_set(&subreq->ref, 2);
+	subreq->rreq = rreq;
+	subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
+	netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
+	netfs_stat(&netfs_n_rh_sreq);
+	return subreq;
+}
+
+void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
+			  enum netfs_sreq_ref_trace what)
+{
+	int r;
+
+	__refcount_inc(&subreq->ref, &r);
+	trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
+			     what);
+}
+
+static void netfs_free_subrequest(struct netfs_io_subrequest *subreq)
+{
+	struct netfs_io_request *rreq = subreq->rreq;
+
+	trace_netfs_sreq(subreq, netfs_sreq_trace_free);
+	if (rreq->netfs_ops->free_subrequest)
+		rreq->netfs_ops->free_subrequest(subreq);
+	mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
+	netfs_stat_d(&netfs_n_rh_sreq);
+	netfs_put_request(rreq, netfs_rreq_trace_put_subreq);
+}
+
+void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
+			  enum netfs_sreq_ref_trace what)
+{
+	unsigned int debug_index = subreq->debug_index;
+	unsigned int debug_id = subreq->rreq->debug_id;
+	bool dead;
+	int r;
+
+	dead = __refcount_dec_and_test(&subreq->ref, &r);
+	trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
+	if (dead)
+		netfs_free_subrequest(subreq);
+}