libnvme(9) API Manual libnvme(9)

# [NAME](#NAME)

enum nvme\_id\_ns\_dlfeat - This field indicates information about features that affect deallocating logical blocks for this namespace.

# [SYNOPSIS](#SYNOPSIS)

enum nvme\_id\_ns\_dlfeat {  
**NVME\_NS\_DLFEAT\_RB** ,  
**NVME\_NS\_DLFEAT\_RB\_NR** ,  
**NVME\_NS\_DLFEAT\_RB\_ALL\_0S** ,  
**NVME\_NS\_DLFEAT\_RB\_ALL\_FS** ,  
**NVME\_NS\_DLFEAT\_WRITE\_ZEROES** ,  
**NVME\_NS\_DLFEAT\_CRC\_GUARD**

};

# [Constants](#Constants)

[NVME\_NS\_DLFEAT\_RB](#NVME_NS_DLFEAT_RB)

Mask to get the value of the read behavior

[NVME\_NS\_DLFEAT\_RB\_NR](#NVME_NS_DLFEAT_RB_NR)

Read behvaior is not reported

[NVME\_NS\_DLFEAT\_RB\_ALL\_0S](#NVME_NS_DLFEAT_RB_ALL_0S)

A deallocated logical block returns all bytes cleared to 0h.

[NVME\_NS\_DLFEAT\_RB\_ALL\_FS](#NVME_NS_DLFEAT_RB_ALL_FS)

A deallocated logical block returns all bytes set to FFh.

[NVME\_NS\_DLFEAT\_WRITE\_ZEROES](#NVME_NS_DLFEAT_WRITE_ZEROES)

If set, indicates that the controller supports the Deallocate bit in the Write Zeroes command for this namespace.

[NVME\_NS\_DLFEAT\_CRC\_GUARD](#NVME_NS_DLFEAT_CRC_GUARD)

If set, indicates that the Guard field for deallocated logical blocks that contain protection information is set to the CRC for the value read from the deallocated logical block and its metadata

enum nvme\_id\_ns\_dlfeat October 2026

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Document: nvme_id_ns_dlfeat-libnvme3(2) from nvme-cli 3.2-r0 (Chainguard OS)
Source: https://github.com/linux-nvme/nvme-cli