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Commit dd748aa4 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

fs_mgr: Add fs_mgr_overlayfs_is_setup() 

Provide a means to determine if overlayfs is currently active with
fs_mgr_overlayfs_is_setup().  Search for current clues in the system
that the overrides are in play.  If /mnt/scratch/ is mounted, that
may be enough of a smoking gun because the resource itself may
interfere with operations.

Related to update_engine calling this function to reject performing
an OTA as its operations are incompatible with the overrides.

Test: adb-remount-test.sh
Bug: 120034852
Change-Id: I641163b1559c1a83fe7d0c336d04c10e9956ad3a
parent bb72b808

fs_mgr/README.overlayfs.md

+6 −0
Original line number Original line Diff line number Diff line
@@ -89,6 +89,12 @@ Caveats 
  if higher than 4.6.

  if higher than 4.6.

- *adb enable-verity* will free up overlayfs and as a bonus the

- *adb enable-verity* will free up overlayfs and as a bonus the

  device will be reverted pristine to before any content was updated.

  device will be reverted pristine to before any content was updated.

  Update engine does not take advantage of this, will perform a full OTA.

- Update engine will not run if *fs_mgr_overlayfs_is_setup*() reports

  true as adb remount overrides are incompatable with an OTA for

  multiple reasons.

  NB: This is not a problem for fastbootd or recovery as overrides are

  disabled for those special boot scenarios.

- If dynamic partitions runs out of space, resizing a logical

- If dynamic partitions runs out of space, resizing a logical

  partition larger may fail because of the scratch partition.

  partition larger may fail because of the scratch partition.

  If this happens, either fastboot flashall or adb enable-verity can

  If this happens, either fastboot flashall or adb enable-verity can

fs_mgr/fs_mgr_overlayfs.cpp

+15 −0
Original line number Original line Diff line number Diff line
@@ -96,6 +96,10 @@ bool fs_mgr_overlayfs_teardown(const char*, bool* change) { 
    return false;

    return false;

}

}





bool fs_mgr_overlayfs_is_setup() {

    return false;

}



#else  // ALLOW_ADBD_DISABLE_VERITY == 0

#else  // ALLOW_ADBD_DISABLE_VERITY == 0





namespace {

namespace {
@@ -924,6 +928,17 @@ bool fs_mgr_overlayfs_teardown(const char* mount_point, bool* change) { 
    return ret;

    return ret;

}

}





bool fs_mgr_overlayfs_is_setup() {

    if (fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false)) return true;

    std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(),

                                                               fs_mgr_free_fstab);

    if (fs_mgr_overlayfs_invalid(fstab.get())) return false;

    for (const auto& mount_point : fs_mgr_candidate_list(fstab.get())) {

        if (fs_mgr_overlayfs_already_mounted(mount_point)) return true;

    }

    return false;

}



#endif  // ALLOW_ADBD_DISABLE_VERITY != 0

#endif  // ALLOW_ADBD_DISABLE_VERITY != 0





bool fs_mgr_has_shared_blocks(const std::string& mount_point, const std::string& dev) {

bool fs_mgr_has_shared_blocks(const std::string& mount_point, const std::string& dev) {

fs_mgr/include/fs_mgr_overlayfs.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -29,6 +29,7 @@ std::vector<std::string> fs_mgr_overlayfs_required_devices( 
bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,

bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,

                            bool* change = nullptr);

                            bool* change = nullptr);

bool fs_mgr_overlayfs_teardown(const char* mount_point = nullptr, bool* change = nullptr);

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_has_shared_blocks(const std::string& mount_point, const std::string& dev);

std::string fs_mgr_get_context(const std::string& mount_point);

std::string fs_mgr_get_context(const std::string& mount_point);