From eadb7525b0700a6390bb99c1f7b7493a93f0d8ac Mon Sep 17 00:00:00 2001
From: oxmc <67136658+oxmc@users.noreply.github.com>
Date: Sun, 7 Jun 2026 02:53:43 -0700
Subject: [PATCH] fstab: make discard opt-in via BOARD_STORAGE_SUPPORTS_DISCARD
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Add fstab.rpi4.discard (metadata with discard) alongside the default
fstab.rpi4 (no discard). device.mk selects between them based on
BOARD_STORAGE_SUPPORTS_DISCARD — set true for SD cards or SSDs that
actually support TRIM, leave unset for USB flash drives.
---
 device.mk                  | 14 ++++++++++++--
 ramdisk/fstab.rpi4.discard | 12 ++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 ramdisk/fstab.rpi4.discard

diff --git a/device.mk b/device.mk
index 4403d3f..246ac80 100644
--- a/device.mk
+++ b/device.mk
@@ -140,9 +140,19 @@ PRODUCT_PACKAGES += \
     com.android.hardware.power
 
 # Ramdisk
+# Set BOARD_STORAGE_SUPPORTS_DISCARD := true in BoardConfig.mk (or a device
+# variant makefile) to enable TRIM on the metadata partition. Only do this if
+# your storage device actually supports discard (SD cards, SSDs) — USB flash
+# drives typically don't, and requesting discard on them stalls jbd2.
+ifeq ($(BOARD_STORAGE_SUPPORTS_DISCARD),true)
+_FSTAB_SRC := $(DEVICE_PATH)/ramdisk/fstab.rpi4.discard
+else
+_FSTAB_SRC := $(DEVICE_PATH)/ramdisk/fstab.rpi4
+endif
+
 PRODUCT_COPY_FILES += \
-    $(DEVICE_PATH)/ramdisk/fstab.rpi4:$(TARGET_COPY_OUT_RAMDISK)/fstab.rpi4 \
-    $(DEVICE_PATH)/ramdisk/fstab.rpi4:$(TARGET_COPY_OUT_VENDOR)/etc/fstab.rpi4 \
+    $(_FSTAB_SRC):$(TARGET_COPY_OUT_RAMDISK)/fstab.rpi4 \
+    $(_FSTAB_SRC):$(TARGET_COPY_OUT_VENDOR)/etc/fstab.rpi4 \
     $(DEVICE_PATH)/ramdisk/init.rpi4.rc:$(TARGET_COPY_OUT_VENDOR)/etc/init/hw/init.rpi4.rc \
     $(DEVICE_PATH)/ramdisk/init.rpi4.usb.rc:$(TARGET_COPY_OUT_VENDOR)/etc/init/hw/init.rpi4.usb.rc \
     $(DEVICE_PATH)/ramdisk/ueventd.rpi4.rc:$(TARGET_COPY_OUT_VENDOR)/etc/ueventd.rc
diff --git a/ramdisk/fstab.rpi4.discard b/ramdisk/fstab.rpi4.discard
new file mode 100644
index 0000000..30f97f0
--- /dev/null
+++ b/ramdisk/fstab.rpi4.discard
@@ -0,0 +1,12 @@
+# Android fstab file.
+# The filesystem that contains the filesystem checker binary (typically /system) cannot
+# specify MF_CHECK, and must come before any filesystems that do specify MF_CHECK
+
+#<src>                                     <mnt_point>  <type>  <mnt_flags and options>                             <fs_mgr_flags>
+/dev/block/by-name/system                  /system      ext4    ro,barrier=1                                        wait,first_stage_mount
+/dev/block/by-name/system_ext              /system_ext  ext4    ro,barrier=1                                        wait,first_stage_mount
+/dev/block/by-name/vendor                  /vendor      ext4    ro,barrier=1                                        wait,first_stage_mount
+/dev/block/by-name/metadata                /metadata    ext4    noatime,nosuid,nodev,discard                        wait,formattable,first_stage_mount
+/dev/block/by-name/userdata                /data        ext4    noatime,nosuid,nodev,nomblk_io_submit,errors=panic  wait,check,formattable,quota
+/devices/platform/scb/*.pcie/*/*/*/usb*    auto         auto    defaults                                            voldmanaged=usb:auto
+/devices/platform/soc/*.usb/usb*           auto         auto    defaults                                            voldmanaged=usb:auto