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
Change-Id: I9ad9e0cd30fd074b3bbf8f450bd401b133d5771a
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index 78d0c07..a6e1344 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -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()
@@ -67,17 +68,18 @@
// record fs stat
enum FsStatFlags {
- FS_STAT_IS_EXT4 = 0x0001,
+ FS_STAT_IS_EXT4 = 0x0001,
FS_STAT_NEW_IMAGE_VERSION = 0x0002,
- FS_STAT_E2FSCK_F_ALWAYS = 0x0004,
- FS_STAT_UNCLEAN_SHUTDOWN = 0x0008,
- FS_STAT_QUOTA_ENABLED = 0x0010,
- FS_STAT_TUNE2FS_FAILED = 0x0020,
- FS_STAT_RO_MOUNT_FAILED = 0x0040,
+ FS_STAT_E2FSCK_F_ALWAYS = 0x0004,
+ FS_STAT_UNCLEAN_SHUTDOWN = 0x0008,
+ FS_STAT_QUOTA_ENABLED = 0x0010,
+ FS_STAT_TUNE2FS_FAILED = 0x0020,
+ FS_STAT_RO_MOUNT_FAILED = 0x0040,
FS_STAT_RO_UNMOUNT_FAILED = 0x0080,
FS_STAT_FULL_MOUNT_FAILED = 0x0100,
- FS_STAT_E2FSCK_FAILED = 0x0200,
- FS_STAT_E2FSCK_FS_FIXED = 0x0400,
+ FS_STAT_E2FSCK_FAILED = 0x0200,
+ FS_STAT_E2FSCK_FS_FIXED = 0x0400,
+ FS_STAT_EXT4_INVALID_MAGIC = 0x0800,
};
/*
@@ -136,6 +138,9 @@
/* 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 @@
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 @@
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);