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Merge "Try to recover corrupted ext4 /data with backup superblock"

This commit is contained in:
Randall Huang 2020-06-11 23:46:17 +00:00 committed by Gerrit Code Review
parent 8d3265539b 72abd7b246
commit 78e0d064c7
1 changed files with 30 additions and 5 deletions
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35
fs_mgr/fs_mgr.cpp
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@ -301,10 +301,13 @@ static bool is_ext4_superblock_valid(const struct ext4_super_block* es) {
return true;
}
static bool needs_block_encryption(const FstabEntry& entry);
static bool should_use_metadata_encryption(const FstabEntry& entry);
// Read the primary superblock from an ext4 filesystem. On failure return
// false. If it's not an ext4 filesystem, also set FS_STAT_INVALID_MAGIC.
static bool read_ext4_superblock(const std::string& blk_device, struct ext4_super_block* sb,
int* fs_stat) {
static bool read_ext4_superblock(const std::string& blk_device, const FstabEntry& entry,
struct ext4_super_block* sb, int* fs_stat) {
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(blk_device.c_str(), O_RDONLY | O_CLOEXEC)));
if (fd < 0) {
@ -321,7 +324,29 @@ static bool read_ext4_superblock(const std::string& blk_device, struct ext4_supe
LINFO << "Invalid ext4 superblock on '" << blk_device << "'";
// not a valid fs, tune2fs, fsck, and mount will all fail.
*fs_stat |= FS_STAT_INVALID_MAGIC;
return false;
bool encrypted = should_use_metadata_encryption(entry) || needs_block_encryption(entry);
if (entry.mount_point == "/data" &&
(!encrypted || android::base::StartsWith(blk_device, "/dev/block/dm-"))) {
// try backup superblock, if main superblock is corrupted
for (unsigned int blocksize = EXT4_MIN_BLOCK_SIZE; blocksize <= EXT4_MAX_BLOCK_SIZE;
blocksize *= 2) {
unsigned int superblock = blocksize * 8;
if (blocksize == EXT4_MIN_BLOCK_SIZE) superblock++;
if (TEMP_FAILURE_RETRY(pread(fd, sb, sizeof(*sb), superblock * blocksize)) !=
sizeof(*sb)) {
PERROR << "Can't read '" << blk_device << "' superblock";
return false;
}
if (is_ext4_superblock_valid(sb) &&
(1 << (10 + sb->s_log_block_size) == blocksize)) {
*fs_stat &= ~FS_STAT_INVALID_MAGIC;
break;
}
}
}
if (*fs_stat & FS_STAT_INVALID_MAGIC) return false;
}
*fs_stat |= FS_STAT_IS_EXT4;
LINFO << "superblock s_max_mnt_count:" << sb->s_max_mnt_count << "," << blk_device;
@ -662,7 +687,7 @@ static int prepare_fs_for_mount(const std::string& blk_device, const FstabEntry&
if (is_extfs(entry.fs_type)) {
struct ext4_super_block sb;
if (read_ext4_superblock(blk_device, &sb, &fs_stat)) {
if (read_ext4_superblock(blk_device, entry, &sb, &fs_stat)) {
if ((sb.s_feature_incompat & EXT4_FEATURE_INCOMPAT_RECOVER) != 0 ||
(sb.s_state & EXT4_VALID_FS) == 0) {
LINFO << "Filesystem on " << blk_device << " was not cleanly shutdown; "
@ -692,7 +717,7 @@ static int prepare_fs_for_mount(const std::string& blk_device, const FstabEntry&
entry.fs_mgr_flags.fs_verity || entry.fs_mgr_flags.ext_meta_csum)) {
struct ext4_super_block sb;
if (read_ext4_superblock(blk_device, &sb, &fs_stat)) {
if (read_ext4_superblock(blk_device, entry, &sb, &fs_stat)) {
tune_reserved_size(blk_device, entry, &sb, &fs_stat);
tune_encrypt(blk_device, entry, &sb, &fs_stat);
tune_verity(blk_device, entry, &sb, &fs_stat);