remount: Prevent error spam when remounting fails.
Cuttlefish's combined fstab has two entries for every partition, which
causes a lot of error spam when remount fails. Fix this by only
remounting entries that match an actual mount point (if such a mount
point exists).
Bug: 241179247
Test: remount on broken kernel
Change-Id: I3ddab553706f98b45f83221fd195f481dfdcc5c0
diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index b1606d9..4fe00d1 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -370,28 +370,6 @@
return ret;
}
-bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point, bool overlay_only = true) {
- Fstab fstab;
- auto save_errno = errno;
- if (!ReadFstabFromFile("/proc/mounts", &fstab)) {
- return false;
- }
- errno = save_errno;
- const auto lowerdir = kLowerdirOption + mount_point;
- for (const auto& entry : fstab) {
- if (overlay_only && "overlay" != entry.fs_type && "overlayfs" != entry.fs_type) continue;
- if (mount_point != entry.mount_point) continue;
- if (!overlay_only) return true;
- const auto options = android::base::Split(entry.fs_options, ",");
- for (const auto& opt : options) {
- if (opt == lowerdir) {
- return true;
- }
- }
- }
- return false;
-}
-
constexpr char kOverlayfsFileContext[] = "u:object_r:overlayfs_file:s0";
bool fs_mgr_overlayfs_setup_dir(const std::string& dir, std::string* overlay, bool* change) {
@@ -1290,8 +1268,23 @@
}
Fstab fs_mgr_overlayfs_candidate_list(const Fstab& fstab) {
+ android::fs_mgr::Fstab mounts;
+ if (!android::fs_mgr::ReadFstabFromFile("/proc/mounts", &mounts)) {
+ PLOG(ERROR) << "Failed to read /proc/mounts";
+ return {};
+ }
+
Fstab candidates;
for (const auto& entry : fstab) {
+ // Filter out partitions whose type doesn't match what's mounted.
+ // This avoids spammy behavior on devices which can mount different
+ // filesystems for each partition.
+ auto proc_mount_point = (entry.mount_point == "/system") ? "/" : entry.mount_point;
+ auto mounted = GetEntryForMountPoint(&mounts, proc_mount_point);
+ if (!mounted || mounted->fs_type != entry.fs_type) {
+ continue;
+ }
+
FstabEntry new_entry = entry;
if (!fs_mgr_overlayfs_already_mounted(entry.mount_point) &&
!fs_mgr_wants_overlayfs(&new_entry)) {
@@ -1698,6 +1691,28 @@
#endif // ALLOW_ADBD_DISABLE_VERITY != 0
+bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point, bool overlay_only) {
+ Fstab fstab;
+ auto save_errno = errno;
+ if (!ReadFstabFromFile("/proc/mounts", &fstab)) {
+ return false;
+ }
+ errno = save_errno;
+ const auto lowerdir = kLowerdirOption + mount_point;
+ for (const auto& entry : fstab) {
+ if (overlay_only && "overlay" != entry.fs_type && "overlayfs" != entry.fs_type) continue;
+ if (mount_point != entry.mount_point) continue;
+ if (!overlay_only) return true;
+ const auto options = android::base::Split(entry.fs_options, ",");
+ for (const auto& opt : options) {
+ if (opt == lowerdir) {
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
bool fs_mgr_has_shared_blocks(const std::string& mount_point, const std::string& dev) {
struct statfs fs;
if ((statfs((mount_point + "/lost+found").c_str(), &fs) == -1) ||
diff --git a/fs_mgr/fs_mgr_remount.cpp b/fs_mgr/fs_mgr_remount.cpp
index 8bc5681..d17e4f7 100644
--- a/fs_mgr/fs_mgr_remount.cpp
+++ b/fs_mgr/fs_mgr_remount.cpp
@@ -186,8 +186,8 @@
if (entry.fs_type == "vfat") {
return false;
}
- if (GetEntryForMountPoint(&candidates, entry.mount_point)) {
- return true;
+ if (auto candidate_entry = GetEntryForMountPoint(&candidates, entry.mount_point)) {
+ return candidate_entry->fs_type == entry.fs_type;
}
if (GetWrappedEntry(candidates, entry)) {
return false;
@@ -196,13 +196,22 @@
}
static Fstab::const_iterator FindPartition(const Fstab& fstab, const std::string& partition) {
+ Fstab mounts;
+ if (!android::fs_mgr::ReadFstabFromFile("/proc/mounts", &mounts)) {
+ LOG(ERROR) << "Failed to read /proc/mounts";
+ return fstab.end();
+ }
+
for (auto iter = fstab.begin(); iter != fstab.end(); iter++) {
const auto mount_point = system_mount_point(*iter);
- if (partition == mount_point) {
- return iter;
- }
- if (partition == android::base::Basename(mount_point)) {
- return iter;
+ if (partition == mount_point || partition == android::base::Basename(mount_point)) {
+ // In case fstab has multiple entries, pick the one that matches the
+ // actual mounted filesystem type.
+ auto proc_mount_point = (iter->mount_point == "/system") ? "/" : iter->mount_point;
+ auto mounted = GetEntryForMountPoint(&mounts, proc_mount_point);
+ if (mounted && mounted->fs_type == iter->fs_type) {
+ return iter;
+ }
}
}
return fstab.end();
@@ -243,7 +252,10 @@
entry = wrap;
}
- if (!IsRemountable(candidates, *entry)) {
+ // If it's already remounted, include it so it gets gracefully skipped
+ // later on.
+ if (!fs_mgr_overlayfs_already_mounted(entry->mount_point) &&
+ !IsRemountable(candidates, *entry)) {
LOG(ERROR) << "Invalid partition " << arg;
return INVALID_PARTITION;
}
diff --git a/fs_mgr/include/fs_mgr_overlayfs.h b/fs_mgr/include/fs_mgr_overlayfs.h
index 21d7cd9..b328052 100644
--- a/fs_mgr/include/fs_mgr_overlayfs.h
+++ b/fs_mgr/include/fs_mgr_overlayfs.h
@@ -33,6 +33,7 @@
bool fs_mgr_overlayfs_teardown(const char* mount_point = nullptr, bool* change = nullptr);
bool fs_mgr_overlayfs_is_setup();
bool fs_mgr_has_shared_blocks(const std::string& mount_point, const std::string& dev);
+bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point, bool overlay_only = true);
std::string fs_mgr_get_context(const std::string& mount_point);
enum class OverlayfsValidResult {