ra8_fs_space_t Struct Reference

A mounted volume's capacity, free space, and cluster geometry. More...

#include <ra8_fs_meta.h>

Data Fields
uint64_t	total_bytes
	Whole data region, in bytes.
uint64_t	free_bytes
	Unallocated data region, in bytes.
uint64_t	used_bytes
	Allocated data region, in bytes.
uint32_t	bytes_per_cluster
	Allocation-unit size in bytes.
uint32_t	total_clusters
	Data-region cluster count.
uint32_t	free_clusters
	Clusters not currently allocated.
uint32_t	used_clusters
	Clusters currently allocated.

Detailed Description

A mounted volume's capacity, free space, and cluster geometry.

What ra8_fs_free_space reports. Byte counts are 64-bit because a 2 TiB volume's byte total overflows 32 bits even though FAT file sizes stay 32-bit; the cluster counts and the per-cluster byte size are 32-bit, matching the on-disk fields they come from.

Invariant

used_clusters + free_clusters == total_clusters.

total_bytes == (uint64_t)total_clusters * bytes_per_cluster (and likewise for free_bytes / used_bytes).

bytes_per_cluster == sectors_per_cluster * bytes_per_sector.

Example:

ra8_fs_space_t sp = {};
if (ra8_fs_free_space(mnt, &sp) == k_ra8_ok && sp.free_bytes < need) {
  // not enough room -- roll the log or refuse the run
}

See also

ra8_fs_free_space()

Since

0.1.0

Definition at line 84 of file ra8_fs_meta.h.

Field Documentation

bytes_per_cluster

uint32_t ra8_fs_space_t::bytes_per_cluster

Allocation-unit size in bytes.

Definition at line 88 of file ra8_fs_meta.h.

free_bytes

uint64_t ra8_fs_space_t::free_bytes

Unallocated data region, in bytes.

Definition at line 86 of file ra8_fs_meta.h.

Referenced by internal_space().

free_clusters

uint32_t ra8_fs_space_t::free_clusters

Clusters not currently allocated.

Definition at line 90 of file ra8_fs_meta.h.

total_bytes

uint64_t ra8_fs_space_t::total_bytes

Whole data region, in bytes.

Definition at line 85 of file ra8_fs_meta.h.

Referenced by internal_space().

total_clusters

uint32_t ra8_fs_space_t::total_clusters

Data-region cluster count.

Definition at line 89 of file ra8_fs_meta.h.

used_bytes

uint64_t ra8_fs_space_t::used_bytes

Allocated data region, in bytes.

Definition at line 87 of file ra8_fs_meta.h.

Referenced by internal_space().

used_clusters

uint32_t ra8_fs_space_t::used_clusters

Clusters currently allocated.

Definition at line 91 of file ra8_fs_meta.h.

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The documentation for this struct was generated from the following file:

• libs/ra8_fs/inc/ra8_fs_meta.h