get_mounted_entry_for_userdata: Realpath block devices from fstabs
Use realpath as a canonical representation of block devices. This makes
it easier to reason about block devices. This also fixes a bug, in which
fs_mgr_get_mounted_entry_for_userdata didn't properly work on devices
that don't support metadata encryption.
Test: atest CtsFsMgrTestCases
Test: atest CtsUserspaceRebootHostSideTestCases
Bug: 153363818
Change-Id: I139c2be46336a632bbaee86667019c075d7de814
Merged-In: I139c2be46336a632bbaee86667019c075d7de814
(cherry picked from commit 7aa37f1f21c83479b047706a8867d8ba225b1691)
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index 12aa1f0..47cf843 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -97,7 +97,6 @@
using android::base::Basename;
using android::base::GetBoolProperty;
using android::base::GetUintProperty;
-using android::base::Readlink;
using android::base::Realpath;
using android::base::SetProperty;
using android::base::StartsWith;
@@ -1573,8 +1572,8 @@
return std::chrono::milliseconds(std::move(value));
}
-static bool fs_mgr_unmount_all_data_mounts(const std::string& block_device) {
- LINFO << __FUNCTION__ << "(): about to umount everything on top of " << block_device;
+static bool fs_mgr_unmount_all_data_mounts(const std::string& data_block_device) {
+ LINFO << __FUNCTION__ << "(): about to umount everything on top of " << data_block_device;
Timer t;
auto timeout = GetMillisProperty("init.userspace_reboot.userdata_remount.timeoutmillis", 5s);
while (true) {
@@ -1586,7 +1585,13 @@
}
// Now proceed with other bind mounts on top of /data.
for (const auto& entry : proc_mounts) {
- if (entry.blk_device == block_device) {
+ std::string block_device;
+ if (StartsWith(entry.blk_device, "/dev/block") &&
+ !Realpath(entry.blk_device, &block_device)) {
+ PWARNING << __FUNCTION__ << "(): failed to realpath " << entry.blk_device;
+ block_device = entry.blk_device;
+ }
+ if (data_block_device == block_device) {
if (umount2(entry.mount_point.c_str(), 0) != 0) {
PERROR << __FUNCTION__ << "(): Failed to umount " << entry.mount_point;
umount_done = false;
@@ -1598,7 +1603,8 @@
return true;
}
if (t.duration() > timeout) {
- LERROR << __FUNCTION__ << "(): Timed out unmounting all mounts on " << block_device;
+ LERROR << __FUNCTION__ << "(): Timed out unmounting all mounts on "
+ << data_block_device;
Fstab remaining_mounts;
if (!ReadFstabFromFile("/proc/mounts", &remaining_mounts)) {
LERROR << __FUNCTION__ << "(): Can't read /proc/mounts";
@@ -1637,14 +1643,11 @@
return true;
}
-FstabEntry* fs_mgr_get_mounted_entry_for_userdata(Fstab* fstab, const FstabEntry& mounted_entry) {
- if (mounted_entry.mount_point != "/data") {
- LERROR << mounted_entry.mount_point << " is not /data";
- return nullptr;
- }
+FstabEntry* fs_mgr_get_mounted_entry_for_userdata(Fstab* fstab,
+ const std::string& data_block_device) {
std::vector<std::string> dm_stack;
- if (!UnwindDmDeviceStack(mounted_entry.blk_device, &dm_stack)) {
- LERROR << "Failed to unwind dm-device stack for " << mounted_entry.blk_device;
+ if (!UnwindDmDeviceStack(data_block_device, &dm_stack)) {
+ LERROR << "Failed to unwind dm-device stack for " << data_block_device;
return nullptr;
}
for (auto& entry : *fstab) {
@@ -1658,15 +1661,15 @@
continue;
}
block_device = entry.blk_device;
- } else if (!Readlink(entry.blk_device, &block_device)) {
- PWARNING << "Failed to read link " << entry.blk_device;
+ } else if (!Realpath(entry.blk_device, &block_device)) {
+ PWARNING << "Failed to realpath " << entry.blk_device;
block_device = entry.blk_device;
}
if (std::find(dm_stack.begin(), dm_stack.end(), block_device) != dm_stack.end()) {
return &entry;
}
}
- LERROR << "Didn't find entry that was used to mount /data onto " << mounted_entry.blk_device;
+ LERROR << "Didn't find entry that was used to mount /data onto " << data_block_device;
return nullptr;
}
@@ -1677,14 +1680,17 @@
LERROR << "Can't read /proc/mounts";
return -1;
}
- std::string block_device;
auto mounted_entry = GetEntryForMountPoint(&proc_mounts, "/data");
if (mounted_entry == nullptr) {
LERROR << "/data is not mounted";
return -1;
}
- block_device = mounted_entry->blk_device;
- auto fstab_entry = fs_mgr_get_mounted_entry_for_userdata(fstab, *mounted_entry);
+ std::string block_device;
+ if (!Realpath(mounted_entry->blk_device, &block_device)) {
+ PERROR << "Failed to realpath " << mounted_entry->blk_device;
+ return -1;
+ }
+ auto fstab_entry = fs_mgr_get_mounted_entry_for_userdata(fstab, block_device);
if (fstab_entry == nullptr) {
LERROR << "Can't find /data in fstab";
return -1;
diff --git a/fs_mgr/include/fs_mgr.h b/fs_mgr/include/fs_mgr.h
index 3d556c9..86090c1 100644
--- a/fs_mgr/include/fs_mgr.h
+++ b/fs_mgr/include/fs_mgr.h
@@ -107,10 +107,9 @@
// it destroys verity devices from device mapper after the device is unmounted.
int fs_mgr_umount_all(android::fs_mgr::Fstab* fstab);
-// Finds a entry in |fstab| that was used to mount a /data |mounted_entry| from
-// /proc/mounts.
+// Finds a entry in |fstab| that was used to mount a /data on |data_block_device|.
android::fs_mgr::FstabEntry* fs_mgr_get_mounted_entry_for_userdata(
- android::fs_mgr::Fstab* fstab, const android::fs_mgr::FstabEntry& mounted_entry);
+ android::fs_mgr::Fstab* fstab, const std::string& data_block_device);
int fs_mgr_remount_userdata_into_checkpointing(android::fs_mgr::Fstab* fstab);
// Finds the dm_bow device on which this block device is stacked, or returns
diff --git a/fs_mgr/tests/fs_mgr_test.cpp b/fs_mgr/tests/fs_mgr_test.cpp
index 16e38f1..46f1c59 100644
--- a/fs_mgr/tests/fs_mgr_test.cpp
+++ b/fs_mgr/tests/fs_mgr_test.cpp
@@ -1006,6 +1006,8 @@
ASSERT_TRUE(ReadFstabFromFile("/proc/mounts", &proc_mounts)) << "Failed to read /proc/mounts";
auto mounted_entry = GetEntryForMountPoint(&proc_mounts, "/data");
ASSERT_NE(mounted_entry, nullptr) << "/data is not mounted";
- ASSERT_NE(nullptr, fs_mgr_get_mounted_entry_for_userdata(&fstab, *mounted_entry))
+ std::string block_device;
+ ASSERT_TRUE(android::base::Realpath(mounted_entry->blk_device, &block_device));
+ ASSERT_NE(nullptr, fs_mgr_get_mounted_entry_for_userdata(&fstab, block_device))
<< "/data wasn't mounted from default fstab";
}