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, 58 insertions, 0 deletions

diff --git a/fs/debugfs/internal.h b/fs/debugfs/internal.h
new file mode 100644
index 000000000..c95699b27
--- /dev/null
+++ b/fs/debugfs/internal.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  internal.h - declarations internal to debugfs
+ *
+ *  Copyright (C) 2016 Nicolai Stange <nicstange@gmail.com>
+ */
+
+#ifndef _DEBUGFS_INTERNAL_H_
+#define _DEBUGFS_INTERNAL_H_
+#include <linux/list.h>
+
+struct file_operations;
+
+struct debugfs_inode_info {
+	struct inode vfs_inode;
+	union {
+		const void *raw;
+		const struct file_operations *real_fops;
+		const struct debugfs_short_fops *short_fops;
+		debugfs_automount_t automount;
+	};
+	void *aux;
+};
+
+static inline struct debugfs_inode_info *DEBUGFS_I(struct inode *inode)
+{
+	return container_of(inode, struct debugfs_inode_info, vfs_inode);
+}
+
+/* declared over in file.c */
+extern const struct file_operations debugfs_noop_file_operations;
+extern const struct file_operations debugfs_open_proxy_file_operations;
+extern const struct file_operations debugfs_full_proxy_file_operations;
+extern const struct file_operations debugfs_full_short_proxy_file_operations;
+
+struct debugfs_fsdata {
+	const struct file_operations *real_fops;
+	const struct debugfs_short_fops *short_fops;
+	struct {
+		refcount_t active_users;
+		struct completion active_users_drained;
+
+		/* protect cancellations */
+		struct mutex cancellations_mtx;
+		struct list_head cancellations;
+		unsigned int methods;
+	};
+};
+
+enum {
+	HAS_READ = 1,
+	HAS_WRITE = 2,
+	HAS_LSEEK = 4,
+	HAS_POLL = 8,
+	HAS_IOCTL = 16
+};
+
+#endif /* _DEBUGFS_INTERNAL_H_ */