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, 262 insertions, 0 deletions

diff --git a/fs/afs/callback.c b/fs/afs/callback.c
new file mode 100644
index 000000000..61354003c
--- /dev/null
+++ b/fs/afs/callback.c
@@ -0,0 +1,262 @@
+/*
+ * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
+ *
+ * This software may be freely redistributed under the terms of the
+ * GNU General Public License.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Authors: David Woodhouse <dwmw2@infradead.org>
+ *          David Howells <dhowells@redhat.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/circ_buf.h>
+#include <linux/sched.h>
+#include "internal.h"
+
+/*
+ * Handle invalidation of an mmap'd file.  We invalidate all the PTEs referring
+ * to the pages in this file's pagecache, forcing the kernel to go through
+ * ->fault() or ->page_mkwrite() - at which point we can handle invalidation
+ * more fully.
+ */
+void afs_invalidate_mmap_work(struct work_struct *work)
+{
+	struct afs_vnode *vnode = container_of(work, struct afs_vnode, cb_work);
+
+	unmap_mapping_pages(vnode->netfs.inode.i_mapping, 0, 0, false);
+}
+
+static void afs_volume_init_callback(struct afs_volume *volume)
+{
+	struct afs_vnode *vnode;
+
+	down_read(&volume->open_mmaps_lock);
+
+	list_for_each_entry(vnode, &volume->open_mmaps, cb_mmap_link) {
+		if (vnode->cb_v_check != atomic_read(&volume->cb_v_break)) {
+			afs_clear_cb_promise(vnode, afs_cb_promise_clear_vol_init_cb);
+			queue_work(system_dfl_wq, &vnode->cb_work);
+		}
+	}
+
+	up_read(&volume->open_mmaps_lock);
+}
+
+/*
+ * Allow the fileserver to request callback state (re-)initialisation.
+ * Unfortunately, UUIDs are not guaranteed unique.
+ */
+void afs_init_callback_state(struct afs_server *server)
+{
+	struct afs_server_entry *se;
+
+	down_read(&server->cell->vs_lock);
+
+	list_for_each_entry(se, &server->volumes, slink) {
+		se->cb_expires_at = AFS_NO_CB_PROMISE;
+		se->volume->cb_expires_at = AFS_NO_CB_PROMISE;
+		trace_afs_cb_v_break(se->volume->vid, atomic_read(&se->volume->cb_v_break),
+				     afs_cb_break_for_s_reinit);
+		if (!list_empty(&se->volume->open_mmaps))
+			afs_volume_init_callback(se->volume);
+	}
+
+	up_read(&server->cell->vs_lock);
+}
+
+/*
+ * actually break a callback
+ */
+void __afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
+{
+	_enter("");
+
+	clear_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
+	if (afs_clear_cb_promise(vnode, afs_cb_promise_clear_cb_break)) {
+		vnode->cb_break++;
+		vnode->cb_v_check = atomic_read(&vnode->volume->cb_v_break);
+		afs_clear_permits(vnode);
+
+		if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)
+			afs_lock_may_be_available(vnode);
+
+		if (reason != afs_cb_break_for_deleted &&
+		    vnode->status.type == AFS_FTYPE_FILE &&
+		    atomic_read(&vnode->cb_nr_mmap))
+			queue_work(system_dfl_wq, &vnode->cb_work);
+
+		trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, true);
+	} else {
+		trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, false);
+	}
+}
+
+void afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
+{
+	write_seqlock(&vnode->cb_lock);
+	__afs_break_callback(vnode, reason);
+	write_sequnlock(&vnode->cb_lock);
+}
+
+/*
+ * Look up a volume by volume ID under RCU conditions.
+ */
+static struct afs_volume *afs_lookup_volume_rcu(struct afs_cell *cell,
+						afs_volid_t vid)
+{
+	struct afs_volume *volume = NULL;
+	struct rb_node *p;
+
+	scoped_seqlock_read(&cell->volume_lock, ss_lock) {
+		/* Unfortunately, rbtree walking doesn't give reliable results
+		 * under just the RCU read lock, so we have to check for
+		 * changes.
+		 */
+		p = rcu_dereference_raw(cell->volumes.rb_node);
+		while (p) {
+			volume = rb_entry(p, struct afs_volume, cell_node);
+
+			if (volume->vid < vid)
+				p = rcu_dereference_raw(p->rb_left);
+			else if (volume->vid > vid)
+				p = rcu_dereference_raw(p->rb_right);
+			else
+				break;
+			volume = NULL;
+		}
+
+		if (volume && afs_try_get_volume(volume, afs_volume_trace_get_callback))
+			break;
+		volume = NULL;
+	}
+
+	return volume;
+}
+
+/*
+ * Allow the fileserver to break callbacks at the volume-level.  This is
+ * typically done when, for example, a R/W volume is snapshotted to a R/O
+ * volume (the only way to change an R/O volume).  It may also, however, happen
+ * when a volserver takes control of a volume (offlining it, moving it, etc.).
+ *
+ * Every file in that volume will need to be reevaluated.
+ */
+static void afs_break_volume_callback(struct afs_server *server,
+				      struct afs_volume *volume)
+	__releases(RCU)
+{
+	struct afs_server_list *slist = rcu_dereference(volume->servers);
+	unsigned int i, cb_v_break;
+
+	write_lock(&volume->cb_v_break_lock);
+
+	for (i = 0; i < slist->nr_servers; i++)
+		if (slist->servers[i].server == server)
+			slist->servers[i].cb_expires_at = AFS_NO_CB_PROMISE;
+	volume->cb_expires_at = AFS_NO_CB_PROMISE;
+
+	cb_v_break = atomic_inc_return_release(&volume->cb_v_break);
+	trace_afs_cb_v_break(volume->vid, cb_v_break, afs_cb_break_for_volume_callback);
+
+	write_unlock(&volume->cb_v_break_lock);
+	rcu_read_unlock();
+
+	if (!list_empty(&volume->open_mmaps))
+		afs_volume_init_callback(volume);
+}
+
+/*
+ * allow the fileserver to explicitly break one callback
+ * - happens when
+ *   - the backing file is changed
+ *   - a lock is released
+ */
+static void afs_break_one_callback(struct afs_server *server,
+				   struct afs_volume *volume,
+				   struct afs_fid *fid)
+{
+	struct super_block *sb;
+	struct afs_vnode *vnode;
+	struct inode *inode;
+
+	/* See if we can find a matching inode - even an I_NEW inode needs to
+	 * be marked as it can have its callback broken before we finish
+	 * setting up the local inode.
+	 */
+	sb = rcu_dereference(volume->sb);
+	if (!sb)
+		return;
+
+	inode = find_inode_rcu(sb, fid->vnode, afs_ilookup5_test_by_fid, fid);
+	if (inode) {
+		vnode = AFS_FS_I(inode);
+		afs_break_callback(vnode, afs_cb_break_for_callback);
+	} else {
+		trace_afs_cb_miss(fid, afs_cb_break_for_callback);
+	}
+}
+
+static void afs_break_some_callbacks(struct afs_server *server,
+				     struct afs_callback_break *cbb,
+				     size_t *_count)
+{
+	struct afs_callback_break *residue = cbb;
+	struct afs_volume *volume;
+	afs_volid_t vid = cbb->fid.vid;
+	size_t i;
+
+	rcu_read_lock();
+	volume = afs_lookup_volume_rcu(server->cell, vid);
+	if (!volume) {
+		/* Ignore breaks on unknown volumes. */
+		rcu_read_unlock();
+		*_count = 0;
+	} else if (cbb->fid.vnode == 0 && cbb->fid.unique == 0) {
+		afs_break_volume_callback(server, volume);
+		*_count -= 1;
+		if (*_count)
+			memmove(cbb, cbb + 1, sizeof(*cbb) * *_count);
+	} else {
+		/* TODO: Find all matching volumes if we couldn't match the server and
+		 * break them anyway.
+		 */
+
+		for (i = *_count; i > 0; cbb++, i--) {
+			if (cbb->fid.vid == vid) {
+				_debug("- Fid { vl=%08llx n=%llu u=%u }",
+				       cbb->fid.vid,
+				       cbb->fid.vnode,
+				       cbb->fid.unique);
+				--*_count;
+				if (volume)
+					afs_break_one_callback(server, volume, &cbb->fid);
+			} else {
+				*residue++ = *cbb;
+			}
+		}
+		rcu_read_unlock();
+	}
+
+	afs_put_volume(volume, afs_volume_trace_put_callback);
+}
+
+/*
+ * allow the fileserver to break callback promises
+ */
+void afs_break_callbacks(struct afs_server *server, size_t count,
+			 struct afs_callback_break *callbacks)
+{
+	_enter("%p,%zu,", server, count);
+
+	ASSERT(server != NULL);
+
+	while (count > 0)
+		afs_break_some_callbacks(server, callbacks, &count);
+}