mount: fix the wrongly stored fs creation time

This bug made our ext2 images non-mountable by ext4 driver.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 54 insertions, 14 deletions

diff --git a/include/bb_e2fs_defs.h b/include/bb_e2fs_defs.h
index 071c660c5..b400f8c11 100644
--- a/include/bb_e2fs_defs.h
+++ b/include/bb_e2fs_defs.h
@@ -406,25 +406,43 @@ struct ext2_super_block {
          * Performance hints.  Directory preallocation should only
          * happen if the EXT2_FEATURE_COMPAT_DIR_PREALLOC flag is on.
          */
-        uint8_t s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
-        uint8_t s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
+        uint8_t         s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
+        uint8_t         s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
         uint16_t        s_reserved_gdt_blocks;  /* Per group table for online growth */
         /*
          * Journaling support valid if EXT2_FEATURE_COMPAT_HAS_JOURNAL set.
          */
-        uint8_t         s_journal_uuid[16];     /* uuid of journal superblock */
-        uint32_t        s_journal_inum;         /* inode number of journal file */
+/*D0*/  uint8_t         s_journal_uuid[16];     /* uuid of journal superblock */
+/*E0*/  uint32_t        s_journal_inum;         /* inode number of journal file */
         uint32_t        s_journal_dev;          /* device number of journal file */
         uint32_t        s_last_orphan;          /* start of list of inodes to delete */
         uint32_t        s_hash_seed[4];         /* HTREE hash seed */
         uint8_t         s_def_hash_version;     /* Default hash version to use */
         uint8_t         s_jnl_backup_type;      /* Default type of journal backup */
         uint16_t        s_reserved_word_pad;
-        uint32_t        s_default_mount_opts;
+/*100*/ uint32_t        s_default_mount_opts;
         uint32_t        s_first_meta_bg;        /* First metablock group */
+        /* ext3 additions */
         uint32_t        s_mkfs_time;            /* When the filesystem was created */
         uint32_t        s_jnl_blocks[17];       /* Backup of the journal inode */
-        uint32_t        s_reserved[172];        /* Padding to the end of the block */
+        /* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
+/*150*/ uint32_t        s_blocks_count_hi;      /* Blocks count */
+        uint32_t        s_r_blocks_count_hi;    /* Reserved blocks count */
+        uint32_t        s_free_blocks_count_hi; /* Free blocks count */
+        uint16_t        s_min_extra_isize;      /* All inodes have at least # bytes */
+        uint16_t        s_want_extra_isize;     /* New inodes should reserve # bytes */
+        uint32_t        s_flags;                /* Miscellaneous flags */
+        uint16_t        s_raid_stride;          /* RAID stride */
+        uint16_t        s_mmp_interval;         /* # seconds to wait in MMP checking */
+        uint64_t        s_mmp_block;            /* Block for multi-mount protection */
+        uint32_t        s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
+        uint8_t         s_log_groups_per_flex;  /* FLEX_BG group size */
+        uint8_t         s_reserved_char_pad2;
+        uint16_t        s_reserved_pad;
+        uint32_t        s_reserved[162];        /* Padding to the end of the block */
+};
+struct BUG_ext2_super_block {
+        char bug[sizeof(struct ext2_super_block) == 1024 ? 1 : -1];
 };
 
 /*
diff --git a/testsuite/mount.tests b/testsuite/mount.tests
index c5891be83..a0bc50888 100755
--- a/testsuite/mount.tests
+++ b/testsuite/mount.tests
@@ -36,7 +36,8 @@ testing "mount -o remount,mand" \
 "mount -o loop mount.image1m $testdir "\
 "&& grep -Fc $testdir </proc/mounts "\
 "&& mount -o remount,mand $testdir "\
-"&& grep -F $testdir </proc/mounts | grep -c '[, ]mand[, ]'" \
+"&& grep -F $testdir </proc/mounts | grep -c '[, ]mand[, ]'"\
+"|| grep -F $testdir </proc/mounts" \
         "1\n""1\n" \
         "" ""
 
@@ -83,4 +84,28 @@ b
         "" ""
 SKIP=
 
+
+testing "mount RO loop" "\
+exec 2>&1
+umount -d mount.dir 2>/dev/null
+rmdir mount.dir     2>/dev/null
+mkdir -p mount.dir
+(
+cd mount.dir                               || { echo 'cd error'; exit 1; }
+mkdir z1 z2                                || { echo 'mkdir error'; exit 1; }
+mount -t tmpfs tmpfs z1                    || { echo 'mount tmpfs error'; exit 1; }
+dd if=/dev/zero of=z1/e2img count=10 bs=1M 2>/dev/null || { echo 'dd error'; exit 1; }
+mke2fs -F z1/e2img                         2>/dev/null >&2 || { echo 'mke2fs error'; exit 1; }
+mount -r -o loop -t ext2 z1/e2img z2       || { echo 'mount -r -o loop error'; exit 1; }
+mount -o remount,ro z1                     || { echo 'mount -o remount,ro error'; exit 1; }
+)
+umount -d mount.dir/z2
+##losetup -d /dev/loop*
+umount -d mount.dir/z1
+rm -rf mount.dir
+echo DONE
+" \
+"DONE\n" "" ""
+
+
 exit $FAILCOUNT
diff --git a/util-linux/mkfs_ext2.c b/util-linux/mkfs_ext2.c
index 69b25c946..3258d7eee 100644
--- a/util-linux/mkfs_ext2.c
+++ b/util-linux/mkfs_ext2.c
@@ -53,11 +53,6 @@
 #define ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT 0
 #define ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX    1
 
-// from e2fsprogs
-#define s_reserved_gdt_blocks s_padding1
-#define s_mkfs_time           s_reserved[0]
-#define s_flags               s_reserved[22]
-
 #define EXT2_HASH_HALF_MD4       1
 #define EXT2_FLAGS_SIGNED_HASH   0x0001
 #define EXT2_FLAGS_UNSIGNED_HASH 0x0002
@@ -482,8 +477,10 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
         STORE_LE(sb->s_magic, EXT2_SUPER_MAGIC);
         STORE_LE(sb->s_inode_size, inodesize);
         // set "Required extra isize" and "Desired extra isize" fields to 28
-        if (inodesize != sizeof(*inode))
-                STORE_LE(sb->s_reserved[21], 0x001C001C);
+        if (inodesize != sizeof(*inode)) {
+                STORE_LE(sb->s_min_extra_isize, 0x001c);
+                STORE_LE(sb->s_want_extra_isize, 0x001c);
+        }
         STORE_LE(sb->s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
         STORE_LE(sb->s_log_block_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
         STORE_LE(sb->s_log_frag_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);