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Commit a962ec0c authored by David Anderson's avatar David Anderson
Browse files

adb: better error messages on deduplicated filesystems. 

If BOARD_EXT4_SHARE_DUP_BLOCKS is true, "adb remount" will error saying
the filesystem is read-only. Instead, it will now list affected
partitions and explain why they can't be remounted.

Bug: 64109868
Test: adb remount with deduplicated system image
Change-Id: Ida737a6be8e9fe9ea26300897d82b1a149e72f6d
parent 53248e47

adb/daemon/remount_service.cpp

+51 −9
Original line number Diff line number Diff line
@@ -25,14 +25,18 @@ 
#include <stdlib.h>

#include <string.h>

#include <sys/mount.h>

#include <sys/vfs.h>

#include <unistd.h>



#include <string>

#include <vector>



#include <android-base/properties.h>

#include <ext4_utils/ext4_utils.h>



#include "adb.h"

#include "adb_io.h"

#include "adb_unique_fd.h"

#include "adb_utils.h"

#include "fs_mgr.h"
@@ -82,7 +86,27 @@ bool make_block_device_writable(const std::string& dev) { 
    return result;

}



static bool remount_partition(int fd, const char* dir) {

static bool fs_has_shared_blocks(const char* dev) {

    struct statfs fs;

    if (statfs(dev, &fs) == -1 || fs.f_type == EXT4_SUPER_MAGIC) {

        return false;

    }

    unique_fd fd(unix_open(dev, O_RDONLY));

    if (fd < 0) {

        return false;

    }

    struct ext4_super_block sb;

    if (lseek64(fd, 1024, SEEK_SET) < 0 || unix_read(fd, &sb, sizeof(sb)) < 0) {

        return false;

    }

    struct fs_info info;

    if (ext4_parse_sb(&sb, &info) < 0) {

        return false;

    }

    return (info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SHARED_BLOCKS) != 0;

}



static bool remount_partition(int fd, const char* dir, std::vector<std::string>& dedup) {

    if (!directory_exists(dir)) {

        return true;

    }
@@ -108,6 +132,12 @@ static bool remount_partition(int fd, const char* dir) { 
        return false;

    }

    if (mount(dev.c_str(), dir, "none", MS_REMOUNT, nullptr) == -1) {

        if (errno == EROFS && fs_has_shared_blocks(dev.c_str())) {

            // We return true so remount_service() can detect that the only

            // failure was deduplicated filesystems.

            dedup.push_back(dev);

            return true;

        }

        WriteFdFmt(fd, "remount of the %s superblock failed: %s\n", dir, strerror(errno));

        return false;

    }
@@ -140,17 +170,29 @@ void remount_service(int fd, void* cookie) { 
    }



    bool success = true;

    std::vector<std::string> dedup;

    if (android::base::GetBoolProperty("ro.build.system_root_image", false)) {

        success &= remount_partition(fd, "/");

        success &= remount_partition(fd, "/", dedup);

    } else {

        success &= remount_partition(fd, "/system");

        success &= remount_partition(fd, "/system", dedup);

    }

    success &= remount_partition(fd, "/odm");

    success &= remount_partition(fd, "/oem");

    success &= remount_partition(fd, "/product");

    success &= remount_partition(fd, "/vendor");

    success &= remount_partition(fd, "/odm", dedup);

    success &= remount_partition(fd, "/oem", dedup);

    success &= remount_partition(fd, "/product", dedup);

    success &= remount_partition(fd, "/vendor", dedup);



    WriteFdExactly(fd, success ? "remount succeeded\n" : "remount failed\n");

    if (!success) {

        WriteFdExactly(fd, "remount failed\n");

    } else if (dedup.empty()) {

        WriteFdExactly(fd, "remount succeeded\n");

    } else {

        WriteFdExactly(fd,

                       "The following partitions are deduplicated and could "

                       "not be remounted:\n");

        for (const std::string& name : dedup) {

            WriteFdFmt(fd, "  %s\n", name.c_str());

        }

    }



    adb_close(fd);

}