Add a new ioctl, FS_IOC_GETLBMD_CAP, to query metadata and protection
info (PI) capabilities. This ioctl returns information about the files
integrity profile. This is useful for userspace applications to
understand a files end-to-end data protection support and configure the
I/O accordingly.
For now this interface is only supported by block devices. However the
design and placement of this ioctl in generic FS ioctl space allows us
to extend it to work over files as well. This maybe useful when
filesystems start supporting PI-aware layouts.
A new structure struct logical_block_metadata_cap is introduced, which
contains the following fields:
1. lbmd_flags: bitmask of logical block metadata capability flags
2. lbmd_interval: the amount of data described by each unit of logical
block metadata
3. lbmd_size: size in bytes of the logical block metadata associated
with each interval
4. lbmd_opaque_size: size in bytes of the opaque block tag associated
with each interval
5. lbmd_opaque_offset: offset in bytes of the opaque block tag within
the logical block metadata
6. lbmd_pi_size: size in bytes of the T10 PI tuple associated with each
interval
7. lbmd_pi_offset: offset in bytes of T10 PI tuple within the logical
block metadata
8. lbmd_pi_guard_tag_type: T10 PI guard tag type
9. lbmd_pi_app_tag_size: size in bytes of the T10 PI application tag
10. lbmd_pi_ref_tag_size: size in bytes of the T10 PI reference tag
11. lbmd_pi_storage_tag_size: size in bytes of the T10 PI storage tag
12. lbmd_rsvd: reserved for future use
The internal logic to fetch the capability is encapsulated in a helper
function blk_get_meta_cap(), which uses the blk_integrity profile
associated with the device. The ioctl returns -EOPNOTSUPP, if
CONFIG_BLK_DEV_INTEGRITY is not enabled.
Suggested-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Anuj Gupta <anuj20.g@xxxxxxxxxxx>
Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
---
block/blk-integrity.c | 53 +++++++++++++++++++++++++++++++++++
block/ioctl.c | 3 ++
include/linux/blk-integrity.h | 7 +++++
include/uapi/linux/fs.h | 43 ++++++++++++++++++++++++++++
4 files changed, 106 insertions(+)
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index e4e2567061f9..f9ad5bdb84f5 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -13,6 +13,7 @@
#include <linux/scatterlist.h>
#include <linux/export.h>
#include <linux/slab.h>
+#include <linux/t10-pi.h>
#include "blk.h"
@@ -54,6 +55,58 @@ int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
return segments;
}
+int blk_get_meta_cap(struct block_device *bdev,
+ struct logical_block_metadata_cap __user *argp)
+{
+ struct blk_integrity *bi = blk_get_integrity(bdev->bd_disk);
+ struct logical_block_metadata_cap meta_cap = {};
+
+ if (!bi)
+ goto out;
+
+ if (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE)
+ meta_cap.lbmd_flags |= LBMD_PI_CAP_INTEGRITY;
+ if (bi->flags & BLK_INTEGRITY_REF_TAG)
+ meta_cap.lbmd_flags |= LBMD_PI_CAP_REFTAG;
+ meta_cap.lbmd_interval = 1 << bi->interval_exp;
+ meta_cap.lbmd_size = bi->tuple_size;
+ if (bi->csum_type == BLK_INTEGRITY_CSUM_NONE) {
+ /* treat entire tuple as opaque block tag */
+ meta_cap.lbmd_opaque_size = bi->tuple_size;
+ goto out;
+ }
+ meta_cap.lbmd_pi_size = bi->pi_size;
+ meta_cap.lbmd_pi_offset = bi->pi_offset;
+ meta_cap.lbmd_opaque_size = bi->tuple_size - bi->pi_size;
+ if (meta_cap.lbmd_opaque_size && !bi->pi_offset)
+ meta_cap.lbmd_opaque_offset = bi->pi_size;
+
+ meta_cap.lbmd_guard_tag_type = bi->csum_type;
+ meta_cap.lbmd_app_tag_size = 2;
+
+ if (bi->flags & BLK_INTEGRITY_REF_TAG) {
+ switch (bi->csum_type) {
+ case BLK_INTEGRITY_CSUM_CRC64:
+ meta_cap.lbmd_ref_tag_size =
+ sizeof_field(struct crc64_pi_tuple, ref_tag);
+ break;
+ case BLK_INTEGRITY_CSUM_CRC:
+ case BLK_INTEGRITY_CSUM_IP:
+ meta_cap.lbmd_ref_tag_size =
+ sizeof_field(struct t10_pi_tuple, ref_tag);
+ break;
+ default:
+ break;
+ }
+ }
+
+out:
+ if (copy_to_user(argp, &meta_cap,
+ sizeof(struct logical_block_metadata_cap)))
+ return -EFAULT;
+ return 0;
+}
+
/**
* blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
* @rq: request to map
diff --git a/block/ioctl.c b/block/ioctl.c
index e472cc1030c6..19782f7b5ff1 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -13,6 +13,7 @@
#include <linux/uaccess.h>
#include <linux/pagemap.h>
#include <linux/io_uring/cmd.h>
+#include <linux/blk-integrity.h>
#include <uapi/linux/blkdev.h>
#include "blk.h"
#include "blk-crypto-internal.h"
@@ -643,6 +644,8 @@ static int blkdev_common_ioctl(struct block_device *bdev, blk_mode_t mode,
return blkdev_pr_preempt(bdev, mode, argp, true);
case IOC_PR_CLEAR:
return blkdev_pr_clear(bdev, mode, argp);
+ case FS_IOC_GETLBMD_CAP:
+ return blk_get_meta_cap(bdev, argp);
default:
return -ENOIOCTLCMD;
}
diff --git a/include/linux/blk-integrity.h b/include/linux/blk-integrity.h
index c7eae0bfb013..b4aff4dff843 100644
--- a/include/linux/blk-integrity.h
+++ b/include/linux/blk-integrity.h
@@ -29,6 +29,8 @@ int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
int blk_rq_integrity_map_user(struct request *rq, void __user *ubuf,
ssize_t bytes);
+int blk_get_meta_cap(struct block_device *bdev,
+ struct logical_block_metadata_cap __user *argp);
static inline bool
blk_integrity_queue_supports_integrity(struct request_queue *q)
@@ -92,6 +94,11 @@ static inline struct bio_vec rq_integrity_vec(struct request *rq)
rq->bio->bi_integrity->bip_iter);
}
#else /* CONFIG_BLK_DEV_INTEGRITY */
+static inline int blk_get_meta_cap(struct block_device *bdev,
+ struct logical_block_metadata_cap __user *argp)
+{
+ return -EOPNOTSUPP;
+}
static inline int blk_rq_count_integrity_sg(struct request_queue *q,
struct bio *b)
{
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 0098b0ce8ccb..70350d5a4cd6 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -91,6 +91,47 @@ struct fs_sysfs_path {
__u8 name[128];
};
+/* Protection info capability flags */
+#define LBMD_PI_CAP_INTEGRITY (1 << 0)
+#define LBMD_PI_CAP_REFTAG (1 << 1)
+
+/* Checksum types for Protection Information */
+#define LBMD_PI_CSUM_NONE 0
+#define LBMD_PI_CSUM_IP 1
+#define LBMD_PI_CSUM_CRC16_T10DIF 2
+#define LBMD_PI_CSUM_CRC64_NVME 4
+
+/*
+ * struct logical_block_metadata_cap - Logical block metadata
+ * @lbmd_flags: Bitmask of logical block metadata capability flags
+ * @lbmd_interval: The amount of data described by each unit of logical block metadata
+ * @lbmd_size: Size in bytes of the logical block metadata associated with each interval
+ * @lbmd_opaque_size: Size in bytes of the opaque block tag associated with each interval
+ * @lbmd_opaque_offset: Offset in bytes of the opaque block tag within the logical block metadata
+ * @lbmd_pi_size: Size in bytes of the T10 PI tuple associated with each interval
+ * @lbmd_pi_offset: Offset in bytes of T10 PI tuple within the logical block metadata
+ * @lbmd_pi_guard_tag_type: T10 PI guard tag type
+ * @lbmd_pi_app_tag_size: Size in bytes of the T10 PI application tag
+ * @lbmd_pi_ref_tag_size: Size in bytes of the T10 PI reference tag
+ * @lbmd_pi_storage_tag_size: Size in bytes of the T10 PI storage tag
+ * @lbmd_rsvd: Reserved for future use
+ */
+
+struct logical_block_metadata_cap {
+ __u32 lbmd_flags;
+ __u16 lbmd_interval;
+ __u8 lbmd_size;
+ __u8 lbmd_opaque_size;
+ __u8 lbmd_opaque_offset;
+ __u8 lbmd_pi_size;
+ __u8 lbmd_pi_offset;
+ __u8 lbmd_guard_tag_type;
+ __u8 lbmd_app_tag_size;
+ __u8 lbmd_ref_tag_size;
+ __u8 lbmd_storage_tag_size;
+ __u8 lbmd_rsvd[17];
+};
+
/* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */
#define FILE_DEDUPE_RANGE_SAME 0
#define FILE_DEDUPE_RANGE_DIFFERS 1
@@ -247,6 +288,8 @@ struct fsxattr {
* also /sys/kernel/debug/ for filesystems with debugfs exports
*/
#define FS_IOC_GETFSSYSFSPATH _IOR(0x15, 1, struct fs_sysfs_path)
+/* Get logical block metadata capability details */
+#define FS_IOC_GETLBMD_CAP _IOR(0x15, 2, struct logical_block_metadata_cap)
/*
* Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
--
2.25.1
