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, 110 insertions, 0 deletions

diff --git a/fs/fuse/dev.h b/fs/fuse/dev.h
new file mode 100644
index 000000000..8d25378c0
--- /dev/null
+++ b/fs/fuse/dev.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _FS_FUSE_DEV_H
+#define _FS_FUSE_DEV_H
+
+#include <linux/cleanup.h>
+
+/** Maximum number of outstanding background requests */
+#define FUSE_DEFAULT_MAX_BACKGROUND 12
+
+struct fuse_conn;
+struct fuse_chan;
+struct fuse_dev;
+struct fuse_args;
+struct fuse_copy_state;
+struct fuse_backing_map;
+struct file;
+struct folio;
+enum fuse_notify_code;
+
+struct fuse_chan_param {
+	unsigned int minor;
+	unsigned int max_write;
+	unsigned int max_pages;
+	bool io_uring_enabled;
+};
+
+struct fuse_chan *fuse_chan_new(void);
+struct fuse_chan *fuse_dev_chan_new(void);
+void fuse_chan_release(struct fuse_chan *fch);
+void fuse_chan_free(struct fuse_chan *fch);
+unsigned int fuse_chan_num_background(struct fuse_chan *fch);
+unsigned int fuse_chan_max_background(struct fuse_chan *fch);
+void fuse_chan_max_background_set(struct fuse_chan *fch, unsigned int val);
+unsigned int fuse_chan_num_waiting(struct fuse_chan *fch);
+void fuse_chan_set_fc(struct fuse_chan *fch, struct fuse_conn *fc);
+void fuse_chan_set_initialized(struct fuse_chan *fch, struct fuse_chan_param *param);
+ssize_t fuse_chan_send(struct fuse_chan *fch, struct fuse_args *args);
+int fuse_chan_send_bg(struct fuse_chan *fch, struct fuse_args *args, gfp_t gfp_flags);
+int fuse_chan_send_notify_reply(struct fuse_chan *fch, struct fuse_args *args, u64 unique);
+void fuse_chan_resend(struct fuse_chan *fch);
+
+struct fuse_forget_link *fuse_alloc_forget(void);
+void fuse_chan_queue_forget(struct fuse_chan *fch, struct fuse_forget_link *forget,
+			    u64 nodeid, u64 nlookup);
+
+DEFINE_FREE(fuse_chan_free, struct fuse_chan *, if (_T) fuse_chan_free(_T))
+
+/**
+ * Initialize the client device
+ */
+int fuse_dev_init(void);
+
+/**
+ * Cleanup the client device
+ */
+void fuse_dev_cleanup(void);
+
+void fuse_dev_install(struct fuse_dev *fud, struct fuse_chan *fch);
+bool fuse_dev_verify(struct fuse_dev *fud, struct fuse_chan *fch);
+void fuse_dev_put(struct fuse_dev *fud);
+bool fuse_dev_is_installed(struct fuse_dev *fud);
+bool fuse_dev_is_sync_init(struct fuse_dev *fud);
+struct fuse_dev *fuse_dev_grab(struct file *file);
+
+void fuse_init_server_timeout(struct fuse_chan *fch, unsigned int timeout);
+
+/* Abort all requests */
+void fuse_chan_abort(struct fuse_chan *fch, bool abort_with_err);
+void fuse_chan_wait_aborted(struct fuse_chan *fch);
+
+/**
+ * Acquire reference to fuse_conn
+ */
+struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
+
+/**
+ * Release reference to fuse_conn
+ */
+void fuse_conn_put(struct fuse_conn *fc);
+
+dev_t fuse_conn_get_id(struct fuse_conn *fc);
+
+void fuse_end_polls(struct fuse_conn *fc);
+int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
+		unsigned int size, struct fuse_copy_state *cs);
+
+int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map);
+int fuse_backing_close(struct fuse_conn *fc, int backing_id);
+
+int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size);
+int fuse_copy_folio(struct fuse_copy_state *cs, struct folio **foliop,
+		    unsigned offset, unsigned count, int zeroing);
+void fuse_copy_finish(struct fuse_copy_state *cs);
+
+#ifdef CONFIG_FUSE_IO_URING
+bool fuse_uring_enabled(void);
+void fuse_uring_destruct(struct fuse_chan *fch);
+#else /* CONFIG_FUSE_IO_URING */
+static inline bool fuse_uring_enabled(void)
+{
+	return false;
+}
+
+static inline void fuse_uring_destruct(struct fuse_chan *fch)
+{
+}
+#endif /* CONFIG_FUSE_IO_URING */
+
+#endif /* _FS_FUSE_DEV_H */