[PATCH 0/2] nvmet: add namespace-level debugfs for reservation state

[Daniel Wagner]

On Mon, Jul 06, 2026 at 11:10:41AM +0800, Guixin Liu wrote:
> > > > Example output with two registered hosts and an active holder:
> > > > 
> > > >    $ cat /sys/kernel/debug/nvmet/testnqn/ns1/reservation
> > > >    enable : 1
> > > >    generation : 2
> > > >    notify_mask : 0x0
> > > >    rtype : write_exclusive
> > > >    holder : hostid=11111111-1111-1111-1111-111111111111, rkey=0x1111
> > > >    registrants:
> > > >      hostid=11111111-1111-1111-1111-111111111111, rkey=0x1111
> > > >      hostid=22222222-2222-2222-2222-222222222222, rkey=0x2222
> > > I expect blktests will make use of this interface eventually. The parser
> > > for this wont be dead simple, sure doable but not simple. If you see a
> > > way to make a bit simpler I wouldn't mind.
> > How about this:
> > 
> > 1. One holer, multi registrants:
> >   enable=1
> >   generation=2
> >   notify_mask=0x0
> >   rtype=write_exclusive
> >   holder=11111111-1111-1111-1111-111111111111,0x1111
> >   reg=11111111-1111-1111-1111-111111111111,0x1111
> >   reg=22222222-2222-2222-2222-222222222222,0x2222
> > 
> > 2. No holder, multi registrants:
> >   enable=1
> >   generation=1
> >   notify_mask=0x0
> >   rtype=none
> >   holder=none
> >   reg=11111111-1111-1111-1111-111111111111,0x1111
> >   reg=22222222-2222-2222-2222-222222222222,0x2222
> > 
> > 3. No registrant:
> >   enable=1
> >   generation=0
> >   notify_mask=0x0
> >   rtype=none
> >   holder=none
> > 
> > 4. Reservation not enabled:
> >   enable=0
> > 
> > Otherwise, the notify_mask can be stringization:
> > 
> >   notify_mask=reg_preempted,resv_released,resv_preempted

Sorry, missed your previous post. This looks easier to parser (*), but I
think it's up to Shiinchiro to make the call.

Thanks,
Daniel

(*) I asked a LLM to generate one and it looks straight forward.

#!/bin/bash

# Clean plaintext data with email/quote formatting completely removed
DATA=$(cat << 'EOF'
  19   enable=1
  20   generation=2
  21   notify_mask=0x0
  22   rtype=write_exclusive
  23   holder=11111111-1111-1111-1111-111111111111,0x1111
  24   reg=11111111-1111-1111-1111-111111111111,0x1111
  25   reg=22222222-2222-2222-2222-222222222222,0x2222
  26 
  27 2. No holder, multi registrants:
  28   enable=1
  29   generation=1
  30   notify_mask=0x0
  31   rtype=none
  32   holder=none
  33   reg=11111111-1111-1111-1111-111111111111,0x1111
  34   reg=22222222-2222-2222-2222-222222222222,0x2222
  35 
  36 3. No registrant:
  37   enable=1
  38   generation=0
  39   notify_mask=0x0
  40   rtype=none
  41   holder=none
  42 
  43 4. Reservation not enabled:
  44   enable=0
EOF
)

# Declare an associative array to store parsed data
declare -A INI_DATA

# Tracks the active section namespace
current_section="1. Default"

# Read line-by-line
while IFS= read -r raw_line; do
    # Strip leading line numbers (e.g., "  19 ") and trim surrounding spaces
    line=$(echo "$raw_line" | sed -E 's/^[[:space:]]*[0-9]+[[:space:]]+//; s/^[[:space:]]+//; s/[[:space:]]+$//')

    # Skip empty lines
    [[ -z "$line" ]] && continue

    # Check if the line is a section header (e.g., "2. No holder, multi registrants:")
    if [[ "$line" =~ ^[0-9]+\. ]]; then
        current_section="$line"
        continue
    fi

    # Parse Key=Value configurations
    if [[ "$line" == *"="* ]]; then
        key="${line%%=*}"
        val="${line#*=}"
        
        # Build a compound key: "SectionName|||KeyName"
        map_key="${current_section}|||${key}"

        # If key already exists in this section, append value using a pipe '|' delimiter
        if [[ -n "${INI_DATA[$map_key]}" ]]; then
            INI_DATA[$map_key]+="|$val"
        else
            INI_DATA[$map_key]="$val"
        fi
    fi
done <<< "$DATA"

# --- Demonstrate Accessing the Generated Arrays ---
echo "=== PARSED DATA STRUCTURE ==="

for compound_key in "${!INI_DATA[@]}"; do
    section="${compound_key%%|||*}"
    key="${compound_key##*|||}"
    raw_value="${INI_DATA[$compound_key]}"

    echo "[$section]"
    
    # If the value contains our delimiter '|', turn it into a real Bash array
    if [[ "$raw_value" == *"|"* ]]; then
        IFS='|' read -r -a val_array <<< "$raw_value"
        echo "  Key '$key' is an ARRAY (${#val_array[@]} elements):"
        for i in "${!val_array[@]}"; do
            echo "    -> index [$i]: ${val_array[$i]}"
        done
    else
        echo "  Key '$key' is a STRING:"
        echo "    -> value: $raw_value"
    fi
    echo "----------------------------------------"
done


=== PARSED DATA STRUCTURE ===
[3. No registrant:]
  Key 'rtype' is a STRING:
    -> value: none
----------------------------------------
[3. No registrant:]
  Key 'generation' is a STRING:
    -> value: 0
----------------------------------------
[1. Default]
  Key 'generation' is a STRING:
    -> value: 2
----------------------------------------
[2. No holder, multi registrants:]
  Key 'holder' is a STRING:
    -> value: none
----------------------------------------
[2. No holder, multi registrants:]
  Key 'reg' is an ARRAY (2 elements):
    -> index [0]: 11111111-1111-1111-1111-111111111111,0x1111
    -> index [1]: 22222222-2222-2222-2222-222222222222,0x2222
----------------------------------------
[2. No holder, multi registrants:]
  Key 'enable' is a STRING:
    -> value: 1
----------------------------------------
[1. Default]
  Key 'enable' is a STRING:
    -> value: 1
----------------------------------------
[1. Default]
  Key 'notify_mask' is a STRING:
    -> value: 0x0
----------------------------------------
[2. No holder, multi registrants:]
  Key 'generation' is a STRING:
    -> value: 1
----------------------------------------
[3. No registrant:]
  Key 'notify_mask' is a STRING:
    -> value: 0x0
----------------------------------------
[1. Default]
  Key 'holder' is a STRING:
    -> value: 11111111-1111-1111-1111-111111111111,0x1111
----------------------------------------
[3. No registrant:]
  Key 'holder' is a STRING:
    -> value: none
----------------------------------------
[2. No holder, multi registrants:]
  Key 'rtype' is a STRING:
    -> value: none
----------------------------------------
[3. No registrant:]
  Key 'enable' is a STRING:
    -> value: 1
----------------------------------------
[4. Reservation not enabled:]
  Key 'enable' is a STRING:
    -> value: 0
----------------------------------------
[1. Default]
  Key 'rtype' is a STRING:
    -> value: write_exclusive
----------------------------------------
[2. No holder, multi registrants:]
  Key 'notify_mask' is a STRING:
    -> value: 0x0
----------------------------------------
[1. Default]
  Key 'reg' is an ARRAY (2 elements):
    -> index [0]: 11111111-1111-1111-1111-111111111111,0x1111
    -> index [1]: 22222222-2222-2222-2222-222222222222,0x2222
----------------------------------------