Support mounting same mount points with different fstab config
This commits allows multiple lines in a fstab have the same mount
point for first-stage mount, where the first successful mount will be
used.
This allows us to specify a common/shared fstab, with different
settings (e.g., ext4, squashfs) per line, to mount different types
of images on the same mount point. e.g., allows the device to mount
GSI (ext4) while support mounting the original squashfs system.img.
Sample fstab:
fstab in dt:
android {
fstab {
odm_ext4 {
dev = "/dev/block/by-name/odm";
mnt_point = "/odm";
type = ext4;
mnt_flags = "ro";
fs_mgr_flags = "slotselect";
};
odm_f2fs {
dev = "/dev/block/by-name/odm";
mnt_point = "/odm";
type = f2fs;
mnt_flags = "ro";
fs_mgr_flags = "slotselect";
};
};
}
fstab in file:
/dev/block/by-name/odm /odm ext4 ro slotselect
/dev/block/by-name/odm /odm f2fs ro slotselect
Test: make & boot & check /proc/mounts
Change-Id: I64892e3007b0cfd7d06dad1cfc664c45305197ee
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index b5ff658..71fe401 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -414,16 +414,32 @@
return entry.mount_point == "/system";
});
- if (system_partition != fstab_.end()) {
- if (!MountPartition(&(*system_partition))) {
- return false;
+ if (system_partition == fstab_.end()) return true;
+
+ bool mounted = false;
+ bool no_fail = false;
+ for (auto it = system_partition; it != fstab_.end();) {
+ if (it->mount_point != "/system") {
+ break;
}
-
- SwitchRoot((*system_partition).mount_point);
-
- fstab_.erase(system_partition);
+ no_fail |= (it->fs_mgr_flags).no_fail;
+ if (MountPartition(&(*it))) {
+ mounted = true;
+ SwitchRoot("/system");
+ break;
+ }
+ it++;
}
+ if (!mounted && !no_fail) {
+ LOG(ERROR) << "Failed to mount /system";
+ return false;
+ }
+
+ auto it = std::remove_if(fstab_.begin(), fstab_.end(),
+ [](const auto& entry) { return entry.mount_point == "/system"; });
+ fstab_.erase(it, fstab_.end());
+
return true;
}
@@ -444,14 +460,12 @@
if (skip_mount_point.empty()) {
continue;
}
- auto removing_entry =
- std::find_if(fstab_.begin(), fstab_.end(), [&skip_mount_point](const auto& entry) {
- return entry.mount_point == skip_mount_point;
- });
- if (removing_entry != fstab_.end()) {
- fstab_.erase(removing_entry);
- LOG(INFO) << "Skip mounting partition: " << skip_mount_point;
- }
+ auto it = std::remove_if(fstab_.begin(), fstab_.end(),
+ [&skip_mount_point](const auto& entry) {
+ return entry.mount_point == skip_mount_point;
+ });
+ fstab_.erase(it, fstab_.end());
+ LOG(INFO) << "Skip mounting partition: " << skip_mount_point;
}
return true;
@@ -462,8 +476,21 @@
if (!TrySkipMountingPartitions()) return false;
- for (auto& fstab_entry : fstab_) {
- if (!MountPartition(&fstab_entry) && !fstab_entry.fs_mgr_flags.no_fail) {
+ for (auto it = fstab_.begin(); it != fstab_.end();) {
+ bool mounted = false;
+ bool no_fail = false;
+ auto start_mount_point = it->mount_point;
+ do {
+ no_fail |= (it->fs_mgr_flags).no_fail;
+ if (!mounted)
+ mounted = MountPartition(&(*it));
+ else
+ LOG(INFO) << "Skip already-mounted partition: " << start_mount_point;
+ it++;
+ } while (it != fstab_.end() && it->mount_point == start_mount_point);
+
+ if (!mounted && !no_fail) {
+ LOG(ERROR) << start_mount_point << " mounted unsuccessfully but it is required!";
return false;
}
}