fs_mgr: overlay: use alternate for backing storage
When we have multiple physical super partitions, it is prudent to
take the alternate super physical partition in its raw entirety
rather than to construct a logical partition out of the current
super partition's limited remaining space.
SideEffect: alternate boot partitions destroyed for the sake of debug
Test: adb-remount-test.sh (including manually disabled to check
both code paths).
Bug: 119885423
Change-Id: I368d3a5619f69de3b0d1fcad73c4b42d25d0d969
diff --git a/fs_mgr/README.overlayfs.md b/fs_mgr/README.overlayfs.md
index 171936b..fbb5f5d 100644
--- a/fs_mgr/README.overlayfs.md
+++ b/fs_mgr/README.overlayfs.md
@@ -95,6 +95,12 @@
multiple reasons.
NB: This is not a problem for fastbootd or recovery as overrides are
disabled for those special boot scenarios.
+- For implementation simplicity on retrofit dynamic partition devices,
+ take the whole alternate super (eg: if "*a*" slot, then the whole of
+ "*system_b*").
+ Since landing a filesystem on the alternate super physical device
+ without differentiating if it is setup to support logical or physical,
+ the alternate slot metadata and previous content will be lost.
- If dynamic partitions runs out of space, resizing a logical
partition larger may fail because of the scratch partition.
If this happens, either fastboot flashall or adb enable-verity can
diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index 25b32c8..fdfe1c0 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -386,8 +386,10 @@
return SlotNumberForSlotSuffix(fs_mgr_get_slot_suffix());
}
+const auto kPhysicalDevice = "/dev/block/by-name/"s;
+
std::string fs_mgr_overlayfs_super_device(uint32_t slot_number) {
- return "/dev/block/by-name/" + fs_mgr_get_super_partition_name(slot_number);
+ return kPhysicalDevice + fs_mgr_get_super_partition_name(slot_number);
}
bool fs_mgr_overlayfs_has_logical(const fstab* fstab) {
@@ -645,10 +647,16 @@
std::string fs_mgr_overlayfs_scratch_device() {
if (!scratch_device_cache.empty()) return scratch_device_cache;
- auto& dm = DeviceMapper::Instance();
- const auto partition_name = android::base::Basename(kScratchMountPoint);
- std::string path;
- if (!dm.GetDmDevicePathByName(partition_name, &path)) return "";
+ // Is this a multiple super device (retrofit)?
+ auto slot_number = fs_mgr_overlayfs_slot_number();
+ auto super_device = fs_mgr_overlayfs_super_device(slot_number);
+ auto path = fs_mgr_overlayfs_super_device(slot_number == 0);
+ if (super_device == path) {
+ // Create from within single super device;
+ auto& dm = DeviceMapper::Instance();
+ const auto partition_name = android::base::Basename(kScratchMountPoint);
+ if (!dm.GetDmDevicePathByName(partition_name, &path)) return "";
+ }
return scratch_device_cache = path;
}
@@ -679,6 +687,10 @@
*scratch_device = fs_mgr_overlayfs_scratch_device();
*partition_exists = fs_mgr_rw_access(*scratch_device);
auto partition_create = !*partition_exists;
+ // Do we need to create a logical "scratch" partition?
+ if (!partition_create && android::base::StartsWith(*scratch_device, kPhysicalDevice)) {
+ return true;
+ }
auto slot_number = fs_mgr_overlayfs_slot_number();
auto super_device = fs_mgr_overlayfs_super_device(slot_number);
if (!fs_mgr_rw_access(super_device)) return false;
@@ -784,6 +796,7 @@
bool fs_mgr_overlayfs_scratch_can_be_mounted(const std::string& scratch_device) {
if (scratch_device.empty()) return false;
if (fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false)) return false;
+ if (android::base::StartsWith(scratch_device, kPhysicalDevice)) return true;
if (fs_mgr_rw_access(scratch_device)) return true;
auto slot_number = fs_mgr_overlayfs_slot_number();
auto super_device = fs_mgr_overlayfs_super_device(slot_number);
diff --git a/fs_mgr/tests/adb-remount-test.sh b/fs_mgr/tests/adb-remount-test.sh
index c7c86eb..561debb 100755
--- a/fs_mgr/tests/adb-remount-test.sh
+++ b/fs_mgr/tests/adb-remount-test.sh
@@ -378,6 +378,11 @@
M=`adb_sh cat /proc/mounts | sed -n 's@\([^ ]*\) /mnt/scratch \([^ ]*\) .*@\2 on \1@p'`
[ -n "${M}" ] &&
echo "${BLUE}[ INFO ]${NORMAL} scratch filesystem ${M}"
+uses_dynamic_scratch=true
+if [ "${M}" != "${M##*/dev/block/by-name/}" ]; then
+ uses_dynamic_scratch=false
+ scratch_partition="${M##*/dev/block/by-name/}"
+fi
scratch_size=`adb_sh df -k /mnt/scratch </dev/null 2>/dev/null |
while read device kblocks used available use mounted on; do
if [ "/mnt/scratch" = "\${mounted}" ]; then
@@ -453,16 +458,30 @@
fastboot flash vendor ||
( fastboot reboot && false) ||
die "fastboot flash vendor"
-# check ${scratch_partition} via fastboot
-fastboot_getvar partition-type:${scratch_partition} raw &&
- fastboot_getvar has-slot:${scratch_partition} no &&
- fastboot_getvar is-logical:${scratch_partition} yes ||
+fastboot_getvar partition-type:${scratch_partition} raw ||
( fastboot reboot && false) ||
die "fastboot can not see ${scratch_partition} parameters"
-echo "${BLUE}[ INFO ]${NORMAL} expect fastboot erase ${scratch_partition} to fail" >&2
-fastboot erase ${scratch_partition} &&
- ( fastboot reboot || true) &&
- die "fastboot can erase ${scratch_partition}"
+if ${uses_dynamic_scratch}; then
+ # check ${scratch_partition} via fastboot
+ fastboot_getvar has-slot:${scratch_partition} no &&
+ fastboot_getvar is-logical:${scratch_partition} yes ||
+ ( fastboot reboot && false) ||
+ die "fastboot can not see ${scratch_partition} parameters"
+else
+ fastboot_getvar is-logical:${scratch_partition} no ||
+ ( fastboot reboot && false) ||
+ die "fastboot can not see ${scratch_partition} parameters"
+fi
+if ! ${uses_dynamic_scratch}; then
+ fastboot reboot-bootloader ||
+ die "Reboot into fastboot"
+fi
+if ${uses_dynamic_scratch}; then
+ echo "${BLUE}[ INFO ]${NORMAL} expect fastboot erase ${scratch_partition} to fail" >&2
+ fastboot erase ${scratch_partition} &&
+ ( fastboot reboot || true) &&
+ die "fastboot can erase ${scratch_partition}"
+fi
echo "${BLUE}[ INFO ]${NORMAL} expect fastboot format ${scratch_partition} to fail" >&2
fastboot format ${scratch_partition} &&
( fastboot reboot || true) &&
@@ -507,12 +526,13 @@
echo "${GREEN}[ RUN ]${NORMAL} test fastboot flash to ${scratch_partition}" >&2
-adb reboot-fastboot &&
- dd if=/dev/zero of=/tmp/adb-remount-test.img bs=4096 count=16 2>/dev/null &&
+adb reboot-fastboot ||
+ die "Reboot into fastbootd"
+dd if=/dev/zero of=/tmp/adb-remount-test.img bs=4096 count=16 2>/dev/null &&
fastboot_wait 2m ||
( rm /tmp/adb-remount-test.img && false) ||
die "reboot into fastboot"
-fastboot flash ${scratch_partition} /tmp/adb-remount-test.img
+fastboot flash --force ${scratch_partition} /tmp/adb-remount-test.img
err=${?}
rm /tmp/adb-remount-test.img
fastboot reboot ||