Documentation/ABI/stable/sysfs-block

Source file repositories/reference/linux-study-clean/Documentation/ABI/stable/sysfs-block

File Facts

System
Linux kernel
Corpus path
Documentation/ABI/stable/sysfs-block
Extension
[no extension]
Size
35087 bytes
Lines
942
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: Documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

What:		/sys/block/<disk>/alignment_offset
Date:		April 2009
Contact:	Martin K. Petersen <martin.petersen@oracle.com>
Description:
		Storage devices may report a physical block size that is
		bigger than the logical block size (for instance a drive
		with 4KB physical sectors exposing 512-byte logical
		blocks to the operating system).  This parameter
		indicates how many bytes the beginning of the device is
		offset from the disk's natural alignment.


What:		/sys/block/<disk>/discard_alignment
Date:		May 2011
Contact:	Martin K. Petersen <martin.petersen@oracle.com>
Description:
		Devices that support discard functionality may
		internally allocate space in units that are bigger than
		the exported logical block size. The discard_alignment
		parameter indicates how many bytes the beginning of the
		device is offset from the internal allocation unit's
		natural alignment.

What:		/sys/block/<disk>/atomic_write_max_bytes
Date:		February 2024
Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
Description:
		[RO] This parameter specifies the maximum atomic write
		size reported by the device. This parameter is relevant
		for merging of writes, where a merged atomic write
		operation must not exceed this number of bytes.
		This parameter may be greater than the value in
		atomic_write_unit_max_bytes as
		atomic_write_unit_max_bytes will be rounded down to a
		power-of-two and atomic_write_unit_max_bytes may also be
		limited by some other queue limits, such as max_segments.
		This parameter - along with atomic_write_unit_min_bytes
		and atomic_write_unit_max_bytes - will not be larger than
		max_hw_sectors_kb, but may be larger than max_sectors_kb.


What:		/sys/block/<disk>/atomic_write_unit_min_bytes
Date:		February 2024
Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
Description:
		[RO] This parameter specifies the smallest block which can
		be written atomically with an atomic write operation. All
		atomic write operations must begin at a
		atomic_write_unit_min boundary and must be multiples of
		atomic_write_unit_min. This value must be a power-of-two.


What:		/sys/block/<disk>/atomic_write_unit_max_bytes
Date:		February 2024
Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
Description:
		[RO] This parameter defines the largest block which can be
		written atomically with an atomic write operation. This
		value must be a multiple of atomic_write_unit_min and must
		be a power-of-two. This value will not be larger than
		atomic_write_max_bytes.


What:		/sys/block/<disk>/atomic_write_boundary_bytes
Date:		February 2024
Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
Description:
		[RO] A device may need to internally split an atomic write I/O
		which straddles a given logical block address boundary. This
		parameter specifies the size in bytes of the atomic boundary if

Annotation

Implementation Notes