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Commit 835239a2 authored by Keun-young Park's avatar Keun-young Park
Browse files

check ext4 magic before running next steps 

- mount, e2fsck, tune2fs will all fail if magic number does not match.
- mismatch always happen for FDE and is wasting boot-up time to try
  all and fail always.
- skip mount steps if it has invalid magic number and do not record
  fs_stat either.
- For ext4 fs with corrupt superblock, e2fsck refuses to do anything if
  superblock magic is invalid. So simply running e2fsck does not help
  anyway.

bug: 36231950
Test: reboot ane check fs_mgr log from dmesg

(cherry picked from commit 6000a3f6)

Change-Id: Ia7120a188c316262da5fdb986c7d9c76db86aa7b
parent fb803d50

fs_mgr/fs_mgr.cpp

+25 −9
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include <ext4_utils/wipe.h>

#include <linux/fs.h>

#include <linux/loop.h>

#include <linux/magic.h>

#include <logwrap/logwrap.h>

#include <private/android_logger.h>  // for __android_log_is_debuggable()
@@ -78,6 +79,7 @@ enum FsStatFlags { 
    FS_STAT_FULL_MOUNT_FAILED = 0x0100,

    FS_STAT_E2FSCK_FAILED = 0x0200,

    FS_STAT_E2FSCK_FS_FIXED = 0x0400,

    FS_STAT_EXT4_INVALID_MAGIC = 0x0800,

};



/*
@@ -136,6 +138,9 @@ static void check_fs(const char *blk_device, char *fs_type, char *target, int *f 


    /* Check for the types of filesystems we know how to check */

    if (!strcmp(fs_type, "ext2") || !strcmp(fs_type, "ext3") || !strcmp(fs_type, "ext4")) {

        if (*fs_stat & FS_STAT_EXT4_INVALID_MAGIC) {  // will fail, so do not try

            return;

        }

        /*

         * First try to mount and unmount the filesystem.  We do this because

         * the kernel is more efficient than e2fsck in running the journal and
@@ -282,6 +287,11 @@ static int do_quota_with_shutdown_check(char *blk_device, char *fs_type, 
                    PERROR << "Can't read '" << blk_device << "' super block";

                    return force_check;

                }

                if (sb.s_magic != EXT4_SUPER_MAGIC) {

                    LINFO << "Invalid ext4 magic:0x" << std::hex << sb.s_magic << "," << blk_device;

                    *fs_stat |= FS_STAT_EXT4_INVALID_MAGIC;

                    return 0;  // not a valid fs, tune2fs, fsck, and mount  will all fail.

                }

                *fs_stat |= FS_STAT_IS_EXT4;

                LINFO << "superblock s_max_mnt_count:" << sb.s_max_mnt_count << "," << blk_device;

                if (sb.s_max_mnt_count == 0xffff) {  // -1 (int16) in ext2, but uint16 in ext4
@@ -542,7 +552,13 @@ static int mount_with_alternatives(struct fstab *fstab, int start_idx, int *end_ 
            int force_check = do_quota_with_shutdown_check(fstab->recs[i].blk_device,

                                                           fstab->recs[i].fs_type,

                                                           &fstab->recs[i], &fs_stat);



            if (fs_stat & FS_STAT_EXT4_INVALID_MAGIC) {

                LERROR << __FUNCTION__ << "(): skipping mount, invalid ext4, mountpoint="

                       << fstab->recs[i].mount_point << " rec[" << i

                       << "].fs_type=" << fstab->recs[i].fs_type;

                mount_errno = EINVAL;  // continue bootup for FDE

                continue;

            }

            if ((fstab->recs[i].fs_mgr_flags & MF_CHECK) || force_check) {

                check_fs(fstab->recs[i].blk_device, fstab->recs[i].fs_type,

                         fstab->recs[i].mount_point, &fs_stat);