mkdumprd: basic support for btrfs subvol

dracut/99kdumpbase/module-setup.sh

@@ -683,16 +683,21 @@ kdump_install_pre_post_conf() {
 }
 
 default_dump_target_install_conf() {
-    local _target _fstype
+    local _target _fstype _subvol _options
     local _mntpoint _save_path
 
     is_user_configured_dump_target && return
 
     _save_path=$(get_bind_mount_source "$(get_save_path)")
     _target=$(get_target_from_path "$_save_path")
-    _mntpoint=$(get_mntpoint_from_target "$_target")
-
+    _options=$(get_mount_info OPTIONS target "$_save_path" -f)
     _fstype=$(get_fs_type_from_target "$_target")
+    if [[ $_fstype == btrfs ]]; then
+        _subvol=$(get_btrfs_subvol_from_mntopt "$_options")
+    fi
+
+    _mntpoint=$(get_mntpoint_from_target "$_target" "$_subvol")
+
     if is_fs_type_nfs "$_fstype"; then
         kdump_collect_netif_usage "$_target"
         _fstype="nfs"

kdump-lib-initramfs.sh

@@ -110,15 +110,29 @@ get_fs_type_from_target()
 
 get_mntpoint_from_target()
 {
-	# get the first TARGET when SOURCE doesn't end with ].
-	# In most cases, a SOURCE ends with ] when fsroot or subvol exists.
-	_mntpoint=$(get_mount_info TARGET,SOURCE source "$1" | grep -v "\]$" | awk 'NR==1 { print $1 }')
-
+	_subvol="$2"
+	if [ -z "$_subvol" ]; then
+		# get the first TARGET when SOURCE doesn't end with ].
+		# In most cases, a SOURCE ends with ] when fsroot or subvol exists.
+		_mntpoint=$(get_mount_info TARGET,SOURCE source "$1" | grep -v "\]$" | awk 'NR==1 { print $1 }')
+	else
+		# btrfs with subvol
+		_mntpoint=$(get_mount_info TARGET,SOURCE source "$1" | grep "\[$_subvol\]$" | awk 'NR==1 { print $1 }')
+	fi
 	# fallback to the old way when _mntpoint is empty.
 	[ -n "$_mntpoint" ] || _mntpoint=$(get_mount_info TARGET source "$1" -f)
 	echo "$_mntpoint"
 }
 
+get_btrfs_subvol_from_mntopt()
+{
+	_subvol=${1#*subvol=}
+	# mount option may not contain subvol
+	[ "$1" != "$_subvol" ] || return 0
+	_subvol=${_subvol%%,*}
+	echo "$_subvol"
+}
+
 is_ssh_dump_target()
 {
 	kdump_get_conf_val ssh | grep -q @

kdump-lib.sh

@@ -177,7 +177,7 @@ get_kdump_targets()
 # part is the bind mounted directory which quotes by bracket "[]".
 get_bind_mount_source()
 {
-	local _mnt _path _src _opt _fstype
+	local _mnt _path _src _opt _fstype _subvol
 	local _fsroot _src_nofsroot
 
 	_mnt=$(df "$1" | tail -1 | awk '{print $NF}')
@@ -200,15 +200,13 @@ get_bind_mount_source()
 
 	_fsroot=${_src#"${_src_nofsroot}"[}
 	_fsroot=${_fsroot%]}
-	_mnt=$(get_mntpoint_from_target "$_src_nofsroot")
-
 	# for btrfs, _fsroot will also contain the subvol value as well, strip it
 	if [[ $_fstype == btrfs ]]; then
-		local _subvol
-		_subvol=${_opt#*subvol=}
-		_subvol=${_subvol%,*}
+		_subvol=$(get_btrfs_subvol_from_mntopt "$_opt")
 		_fsroot=${_fsroot#"$_subvol"}
 	fi
+	_mnt=$(get_mntpoint_from_target "$_src_nofsroot" "$_subvol")
+
 	echo "$_mnt$_fsroot$_path"
 }
 
@@ -219,11 +217,12 @@ get_mntopt_from_target()
 
 # Get the path where the target will be mounted in kdump kernel
 # $1: kdump target device
+# $2: btrfs subvol
 get_kdump_mntpoint_from_target()
 {
 	local _mntpoint
 
-	_mntpoint=$(get_mntpoint_from_target "$1")
+	_mntpoint=$(get_mntpoint_from_target "$1" "$2")
 	# mount under /sysroot if dump to root disk or mount under
 	# mount under /kdumproot if dump target is not mounted in first kernel
 	# mount under /kdumproot/$_mntpoint in other cases in 2nd kernel.

mkdumprd

@@ -76,10 +76,13 @@ to_mount()
 {
 	local _target=$1 _fstype=$2 _options=$3 _sed_cmd _new_mntpoint _pdev
 
-	_new_mntpoint=$(get_kdump_mntpoint_from_target "$_target")
 	_fstype="${_fstype:-$(get_fs_type_from_target "$_target")}"
 	_options="${_options:-$(get_mntopt_from_target "$_target")}"
 	_options="${_options:-defaults}"
+	if [[ $_fstype == btrfs ]]; then
+		_subvol=$(get_btrfs_subvol_from_mntopt "$_options")
+	fi
+	_new_mntpoint=$(get_kdump_mntpoint_from_target "$_target" "$_subvol")
 
 	if [[ $_fstype == "nfs"* ]]; then
 		_pdev=$_target
@@ -146,7 +149,7 @@ mkdir_save_path_ssh()
 #$1=dump target
 get_fs_size()
 {
-	df --output=avail "$(get_mntpoint_from_target "$1")/$SAVE_PATH" | tail -1
+	df --output=avail "$(get_mntpoint_from_target "$1" "$2")/$SAVE_PATH" | tail -1
 }
 
 #Function: get_raw_size
@@ -159,6 +162,7 @@ get_raw_size()
 #Function: check_size
 #$1: dump type string ('raw', 'fs', 'ssh')
 #$2: dump target
+#$3: btrfs subvol
 check_size()
 {
 	local avail memtotal
@@ -172,7 +176,7 @@ check_size()
 		avail=$(get_ssh_size "$2")
 		;;
 	fs)
-		avail=$(get_fs_size "$2")
+		avail=$(get_fs_size "$2" "$3")
 		;;
 	*)
 		return
@@ -302,20 +306,24 @@ add_mount()
 #handle the case user does not specify the dump target explicitly
 handle_default_dump_target()
 {
-	local _target
-	local _mntpoint
+	local _target _mntpoint _fstype _subvol _options
 
 	is_user_configured_dump_target && return
 
 	check_save_path_fs "$SAVE_PATH"
 
 	_save_path=$(get_bind_mount_source "$SAVE_PATH")
+	_options=$(get_mount_info OPTIONS target "$_save_path" -f)
 	_target=$(get_target_from_path "$_save_path")
-	_mntpoint=$(get_mntpoint_from_target "$_target")
+	_fstype=$(get_fs_type_from_target "$_target")
+	if [[ $_fstype == btrfs ]]; then
+		_subvol=$(get_btrfs_subvol_from_mntopt "$_options")
+	fi
 
+	_mntpoint=$(get_mntpoint_from_target "$_target" "$_subvol")
 	SAVE_PATH=${_save_path##"$_mntpoint"}
-	add_mount "$_target"
-	check_size fs "$_target"
+	add_mount "$_target" "$_fstype" "$_options"
+	check_size fs "$_target" "$_subvol"
 }
 
 # firstly get right SSH_KEY_LOCATION

spec/kdump-lib-initramfs_spec.sh

@@ -67,6 +67,12 @@ Describe 'kdump-lib-initramfs'
 				else
 					printf '/var %s[/ostree/deploy/default/var]\n/sysroot %s\n' "$7" "$7"
 				fi
+			elif [[ "$7" == '/dev/nvme0n1p3' ]]; then
+				if [[ "$8" == "-f" ]]; then
+					printf '/ /dev/nvme0n1p3[/root]\n'
+				else
+					printf '/ /dev/nvme0n1p3[/root]\n/var /dev/nvme0n1p3[/var]\n'
+				fi
 			fi
 		}
 
@@ -76,19 +82,51 @@ Describe 'kdump-lib-initramfs'
 			#  - IPv6 NFS target also contain '[' in the export
 			#  - local dumping target that has '[' in the name
 			#  - has bind mint
+			#  - has subvol
 			Parameters
-				'eng.redhat.com:/srv/[nfs]' '/mnt'
-				'[2620:52:0:a1:217:38ff:fe01:131]:/srv/[nfs]' '/mnt'
-				'/dev/mapper/rhel[disk]' '/'
-				'/dev/vda4' '/sysroot'
+				'eng.redhat.com:/srv/[nfs]' '' '/mnt'
+				'[2620:52:0:a1:217:38ff:fe01:131]:/srv/[nfs]' '' '/mnt'
+				'/dev/mapper/rhel[disk]' '' '/'
+				'/dev/vda4' '' '/sysroot'
+				'/dev/nvme0n1p3' '/var' '/var'
 			End
 
 			It 'should handle all cases correctly'
-				When call get_mntpoint_from_target "$1"
-				The output should equal "$2"
+				When call get_mntpoint_from_target "$1" "$2"
+				The output should equal "$3"
 			End
 		End
 
 	End
 
+	Describe 'Test get_btrfs_subvol_from_mntopt'
+		Context 'Given different mount option formats'
+			# Test the following cases:
+			#  - Standard subvol option at the beginning
+			#  - Standard subvol option in the middle
+			#  - Standard subvol option at the end
+			#  - Subvol with @ prefix (common btrfs pattern)
+			#  - Subvol with complex path
+			#  - No subvol option present
+			#  - Empty mount options
+			#  - Subvol option with no value
+			#  - Similar but different option names
+			Parameters
+				"subvol=/home,rw,relatime" "/home"
+				"rw,subvol=/root,defaults" "/root"
+				"rw,relatime,subvol=/root" "/root"
+				"subvol=@home" "@home"
+				"subvol=/path/to/subvolume,rw" "/path/to/subvolume"
+				"rw,relatime,defaults" ""
+				true ''
+				"subvol=,rw" ""
+				"rw,subvolume=@home" ""
+			End
+
+			It 'should extract subvolume correctly'
+				When call get_btrfs_subvol_from_mntopt "$1"
+				The output should equal "$2"
+			End
+		End
+	End
 End

spec/kdump-lib_spec.sh

@@ -133,4 +133,52 @@ Describe 'kdump-lib'
 		End
 	End
 
+	Describe "get_kdump_mntpoint_from_target with btrfs subvolume support"
+		# Mock get_mntpoint_from_target to simulate different mount scenarios
+		get_mntpoint_from_target() {
+			local device="$1" subvol="$2"
+			case "$device" in
+				'/dev/sda1')
+					if [[ "$subvol" == "@home" ]]; then
+						echo "/mnt/btrfs"
+					elif [[ "$subvol" == "/root" ]]; then
+						echo "/"
+					else
+						echo "/"
+					fi
+					;;
+				'/dev/sdb1')
+					if [[ "$subvol" == "@backup" ]]; then
+						echo "/backup"
+					else
+						echo "/backup"
+					fi
+					;;
+				*)
+					echo "/"
+					;;
+			esac
+		}
+
+		Context 'Given various mount point scenarios with subvolumes'
+			# Test the following cases:
+			#  - Root filesystem with @ subvolume -> /sysroot
+			#  - Home subvolume on non-root -> /kdumproot/mnt/btrfs
+			#  - Backup subvolume -> /kdumproot/backup
+			#  - Regular filesystem without subvolume -> /sysroot
+			Parameters
+				'/dev/sda1 /root /sysroot'
+				'/dev/sda1 @home /kdumproot/mnt/btrfs'
+				'/dev/sdb1 @backup /kdumproot/backup'
+				'/dev/vda2 "" /sysroot'
+			End
+
+			It 'should handle btrfs subvolumes correctly'
+				# Parse parameters: device subvol expected_result
+				read -r device subvol expected_result <<< "$1"
+				When call get_kdump_mntpoint_from_target "$device" "$subvol"
+				The output should equal "$expected_result"
+			End
+		End
+	End
 End