/*
    * Copyright (C) 2010 The Android Open Source Project
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  #include "ext4_utils.h"
  #include "ext4_extents.h"
  #include "allocate.h"
  #include "ext4fixup.h"
  
  #include <sparse/sparse.h>
  
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #include <sys/mman.h>
  #include <fcntl.h>
  #include <unistd.h>
  
  /* The inode block count for a file/directory is in units of 512 byte blocks,
   * _NOT_ the filesystem block size!
   */
  #define INODE_BLOCK_SIZE 512
  
  #define MAX_EXT4_BLOCK_SIZE 4096
  
  /* The two modes the recurse_dir() can be in */
  #define SANITY_CHECK_PASS 1
  #define MARK_INODE_NUMS   2
  #define UPDATE_INODE_NUMS 3
  
  /* Magic numbers to indicate what state the update process is in */
  #define MAGIC_STATE_MARKING_INUMS  0x7000151515565512ll
  #define MAGIC_STATE_UPDATING_INUMS 0x6121131211735123ll
  #define MAGIC_STATE_UPDATING_SB    0x15e1715151558477ll
  
  /* Internal state variables corresponding to the magic numbers */
  #define STATE_UNSET          0
  #define STATE_MARKING_INUMS  1
  #define STATE_UPDATING_INUMS 2
  #define STATE_UPDATING_SB    3
  
  /* Used for automated testing of this programs ability to stop and be restarted wthout error */
  static int bail_phase = 0;
  static int bail_loc = 0;
  static int bail_count = 0;
  static int count = 0;
  
  /* global flags */
  static int verbose = 0;
  static int no_write = 0;
  
  static int new_inodes_per_group = 0;
  
  static int no_write_fixup_state = 0;
  
  static int compute_new_inum(unsigned int old_inum)
  {
      unsigned int group, offset;
  
      group = (old_inum - 1) / info.inodes_per_group;
      offset = (old_inum -1) % info.inodes_per_group;
  
      return (group * new_inodes_per_group) + offset + 1;
  }
  
  static int get_fs_fixup_state(int fd)
  {
      unsigned long long magic;
      int ret, len;
  
      if (no_write) {
          return no_write_fixup_state;
      }
  
      lseek(fd, 0, SEEK_SET);
      len = read(fd, &magic, sizeof(magic));
      if (len != sizeof(magic)) {
          critical_error("cannot read fixup_state\n");
      }
  
      switch (magic) {
          case MAGIC_STATE_MARKING_INUMS:
              ret = STATE_MARKING_INUMS;
              break;
          case MAGIC_STATE_UPDATING_INUMS:
              ret = STATE_UPDATING_INUMS;
              break;
          case MAGIC_STATE_UPDATING_SB:
             ret = STATE_UPDATING_SB;
             break;
         default:
             ret = STATE_UNSET;
     }
     return ret;
 }
 
 static int set_fs_fixup_state(int fd, int state)
 {
     unsigned long long magic;
     struct ext4_super_block sb;
     int len;
 
     if (no_write) {
         no_write_fixup_state = state;
         return 0;
     }
 
     switch (state) {
         case STATE_MARKING_INUMS:
             magic = MAGIC_STATE_MARKING_INUMS;
             break;
         case STATE_UPDATING_INUMS:
             magic = MAGIC_STATE_UPDATING_INUMS;
             break;
         case STATE_UPDATING_SB:
             magic = MAGIC_STATE_UPDATING_SB;
             break;
         case STATE_UNSET:
         default:
             magic = 0ll;
             break;
     }
 
     lseek(fd, 0, SEEK_SET);
     len = write(fd, &magic, sizeof(magic));
     if (len != sizeof(magic)) {
         critical_error("cannot write fixup_state\n");
     }
 
     read_sb(fd, &sb);
     if (magic) {
         /* If we are in the process of updating the filesystem, make it unmountable */
         sb.s_desc_size |= 1;
     } else {
         /* we are done, so make the filesystem mountable again */
         sb.s_desc_size &= ~1;
     }
 
     if (!no_write) {
         write_sb(fd, 1024, &sb);
     }
 
     return 0;
 }
 
 static int read_inode(int fd, unsigned int inum, struct ext4_inode *inode)
 {
     unsigned int bg_num, bg_offset;
     off_t inode_offset;
     int len;
 
     bg_num = (inum-1) / info.inodes_per_group;
     bg_offset = (inum-1) % info.inodes_per_group;
 
     inode_offset = ((unsigned long long)aux_info.bg_desc[bg_num].bg_inode_table * info.block_size) +
                     (bg_offset * info.inode_size);
 
     if (lseek(fd, inode_offset, SEEK_SET) < 0) {
         critical_error_errno("failed to seek to inode %d\n", inum);
     }
 
     len=read(fd, inode, sizeof(*inode));
     if (len != sizeof(*inode)) {
         critical_error_errno("failed to read inode %d\n", inum);
     }
 
     return 0;
 }
 
 static int read_block(int fd, unsigned long long block_num, void *block)
 {
     off_t off;
     unsigned int len;
 
     off = block_num * info.block_size;
 
     if (lseek(fd, off, SEEK_SET) , 0) {
         critical_error_errno("failed to seek to block %lld\n", block_num);
     }
 
     len=read(fd, block, info.block_size);
     if (len != info.block_size) {
         critical_error_errno("failed to read block %lld\n", block_num);
     }
 
     return 0;
 }
 
 static int write_block(int fd, unsigned long long block_num, void *block)
 {
     off_t off;
     unsigned int len;
 
     if (no_write) {
         return 0;
     }
 
     off = block_num * info.block_size;
 
     if (lseek(fd, off, SEEK_SET) < 0) {
         critical_error_errno("failed to seek to block %lld\n", block_num);
     }
 
     len=write(fd, block, info.block_size);
     if (len != info.block_size) {
         critical_error_errno("failed to write block %lld\n", block_num);
     }
 
     return 0;
 }
 
 static void check_inode_bitmap(int fd, unsigned int bg_num)
 {
     unsigned int inode_bitmap_block_num;
     unsigned char block[MAX_EXT4_BLOCK_SIZE];
     int i, bitmap_updated = 0;
 
     /* Using the bg_num, aux_info.bg_desc[], info.inodes_per_group and
      * new_inodes_per_group, retrieve the inode bitmap, and make sure
      * the bits between the old and new size are clear
      */
     inode_bitmap_block_num = aux_info.bg_desc[bg_num].bg_inode_bitmap;
 
     read_block(fd, inode_bitmap_block_num, block);
 
     for (i = info.inodes_per_group; i < new_inodes_per_group; i++) {
         if (bitmap_get_bit(block, i)) {
             bitmap_clear_bit(block, i);
             bitmap_updated = 1;
         }
     }
 
     if (bitmap_updated) {
         if (verbose) {
             printf("Warning: updated inode bitmap for block group %d\n", bg_num);
         }
         write_block(fd, inode_bitmap_block_num, block);
     }
 
     return;
 }
 
 /* Update the superblock and bgdesc of the specified block group */
 static int update_superblocks_and_bg_desc(int fd, int state)
 {
     off_t ret;
     struct ext4_super_block sb;
     unsigned int num_block_groups, total_new_inodes;
     unsigned int i;
 
 
     read_sb(fd, &sb);
 
     /* Compute how many more inodes are now available */
     num_block_groups = DIV_ROUND_UP(aux_info.len_blocks, info.blocks_per_group);
     total_new_inodes = num_block_groups * (new_inodes_per_group - sb.s_inodes_per_group);
 
     if (verbose) {
         printf("created %d additional inodes\n", total_new_inodes);
     }
 
     /* Update the free inodes count in each block group descriptor */
     for (i = 0; i < num_block_groups; i++) {
        if (state == STATE_UPDATING_SB) {
            aux_info.bg_desc[i].bg_free_inodes_count += (new_inodes_per_group - sb.s_inodes_per_group);
        }
        check_inode_bitmap(fd, i);
     }
 
     /* First some sanity checks */
     if ((sb.s_inodes_count + total_new_inodes) != (new_inodes_per_group * num_block_groups)) {
         critical_error("Failed sanity check on new inode count\n");
     }
     if (new_inodes_per_group % (info.block_size/info.inode_size)) {
         critical_error("Failed sanity check on new inode per group alignment\n");
     }
 
     /* Update the free inodes count in the superblock */
     sb.s_inodes_count += total_new_inodes;
     sb.s_free_inodes_count += total_new_inodes;
     sb.s_inodes_per_group = new_inodes_per_group;
 
     for (i = 0; i < aux_info.groups; i++) {
         if (ext4_bg_has_super_block(i)) {
             unsigned int sb_offset;
 
             if (i == 0) {
               /* The first superblock is offset by 1K to leave room for boot sectors */
               sb_offset = 1024;
             } else {
               sb_offset = 0;
             }
 
             sb.s_block_group_nr = i;
             /* Don't write out the backup superblocks with the bit set in the s_desc_size
              * which prevents the filesystem from mounting.  The bit for the primary
              * superblock will be cleared on the final call to set_fs_fixup_state() */
             if (i != 0) {
                 sb.s_desc_size &= ~1;
             }
 
             if (!no_write) {
                 write_sb(fd,
                          (unsigned long long)i
                          * info.blocks_per_group * info.block_size
                          + sb_offset,
                          &sb);
             }
 
             ret = lseek(fd, ((unsigned long long)i * info.blocks_per_group * info.block_size) +
                               (info.block_size * (aux_info.first_data_block + 1)), SEEK_SET);
             if (ret < 0)
                 critical_error_errno("failed to seek to block group descriptors");
 
             if (!no_write) {
                 ret = write(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
                 if (ret < 0)
                     critical_error_errno("failed to write block group descriptors");
                 if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
                     critical_error("failed to write all of block group descriptors");
             }
         }
         if ((bail_phase == 4) && ((unsigned int)bail_count == i)) {
             critical_error("bailing at phase 4\n");
         }
     }
 
     return 0;
 }
 
 
 static int get_direct_blocks(struct ext4_inode *inode, unsigned long long *block_list,
                                                        unsigned int *count)
 {
     unsigned int i = 0;
     unsigned int ret = 0;
     unsigned int sectors_per_block;
 
     sectors_per_block = info.block_size / INODE_BLOCK_SIZE;
     while ((i < (inode->i_blocks_lo / sectors_per_block)) && (i < EXT4_NDIR_BLOCKS)) {
         block_list[i] = inode->i_block[i];
         i++;
     }
 
     *count += i;
 
     if ((inode->i_blocks_lo / sectors_per_block) > EXT4_NDIR_BLOCKS) {
         ret = 1;
     }
 
     return ret;
 }
 
 static int get_indirect_blocks(int fd, struct ext4_inode *inode,
                                unsigned long long *block_list, unsigned int *count)
 {
     unsigned int i;
     unsigned int *indirect_block;
     unsigned int sectors_per_block;
 
     sectors_per_block = info.block_size / INODE_BLOCK_SIZE;
 
     indirect_block = (unsigned int *)malloc(info.block_size);
     if (indirect_block == 0) {
         critical_error("failed to allocate memory for indirect_block\n");
     }
 
     read_block(fd, inode->i_block[EXT4_NDIR_BLOCKS], indirect_block);
 
     for(i = 0; i < (inode->i_blocks_lo / sectors_per_block - EXT4_NDIR_BLOCKS); i++) {
        block_list[EXT4_NDIR_BLOCKS+i] = indirect_block[i];
     }
 
     *count += i;
 
     free(indirect_block);
 
     return 0;
 }
 
 static int get_block_list_indirect(int fd, struct ext4_inode *inode, unsigned long long *block_list)
 {
     unsigned int count=0;
 
     if (get_direct_blocks(inode, block_list, &count)) {
         get_indirect_blocks(fd, inode, block_list, &count);
     }
 
     return count;
 }
 
 static int get_extent_ents(struct ext4_extent_header *ext_hdr, unsigned long long *block_list)
 {
     int i, j;
     struct ext4_extent *extent;
     off_t fs_block_num;
 
     if (ext_hdr->eh_depth != 0) {
         critical_error("get_extent_ents called with eh_depth != 0\n");
     }
 
     /* The extent entries immediately follow the header, so add 1 to the pointer
      * and cast it to an extent pointer.
      */
     extent = (struct ext4_extent *)(ext_hdr + 1);
 
     for (i = 0; i < ext_hdr->eh_entries; i++) {
          fs_block_num = ((off_t)extent->ee_start_hi << 32) | extent->ee_start_lo;
          for (j = 0; j < extent->ee_len; j++) {
              block_list[extent->ee_block+j] = fs_block_num+j;
          }
          extent++;
     }
 
     return 0;
 }
 
 static int get_extent_idx(int fd, struct ext4_extent_header *ext_hdr, unsigned long long *block_list)
 {
     int i;
     struct ext4_extent_idx *extent_idx;
     struct ext4_extent_header *tmp_ext_hdr;
     off_t fs_block_num;
     unsigned char block[MAX_EXT4_BLOCK_SIZE];
 
     /* Sanity check */
     if (ext_hdr->eh_depth == 0) {
         critical_error("get_extent_idx called with eh_depth == 0\n");
     }
 
     /* The extent entries immediately follow the header, so add 1 to the pointer
      * and cast it to an extent pointer.
      */
     extent_idx = (struct ext4_extent_idx *)(ext_hdr + 1);
 
     for (i = 0; i < ext_hdr->eh_entries; i++) {
          fs_block_num = ((off_t)extent_idx->ei_leaf_hi << 32) | extent_idx->ei_leaf_lo;
          read_block(fd, fs_block_num, block);
          tmp_ext_hdr = (struct ext4_extent_header *)block;
 
          if (tmp_ext_hdr->eh_depth == 0) {
              get_extent_ents(tmp_ext_hdr, block_list); /* leaf node, fill in block_list */
          } else {
              get_extent_idx(fd, tmp_ext_hdr, block_list); /* recurse down the tree */
          }
     }
 
     return 0;
 }
 
 static int get_block_list_extents(int fd, struct ext4_inode *inode, unsigned long long *block_list)
 {
     struct ext4_extent_header *extent_hdr;
 
     extent_hdr = (struct ext4_extent_header *)inode->i_block;
 
     if (extent_hdr->eh_magic != EXT4_EXT_MAGIC) {
         critical_error("extent header has unexpected magic value 0x%4.4x\n",
                        extent_hdr->eh_magic);
     }
 
     if (extent_hdr->eh_depth == 0) {
          get_extent_ents((struct ext4_extent_header *)inode->i_block, block_list);
          return 0;
     }
 
     get_extent_idx(fd, (struct ext4_extent_header *)inode->i_block, block_list);
 
     return 0;
 }
 
 static int is_entry_dir(int fd, struct ext4_dir_entry_2 *dirp, int pass)
 {
     struct ext4_inode inode;
     int ret = 0;
 
     if (dirp->file_type == EXT4_FT_DIR) {
         ret = 1;
     } else if (dirp->file_type == EXT4_FT_UNKNOWN) {
         /* Somebody was too lazy to fill in the dir entry,
          * so we have to go fetch it from the inode. Grrr.
          */
         /* if UPDATE_INODE_NUMS pass and the inode high bit is not
          * set return false so we don't recurse down the tree that is
          * already updated.  Otherwise, fetch inode, and return answer.
          */
         if ((pass == UPDATE_INODE_NUMS) && !(dirp->inode & 0x80000000)) {
             ret = 0;
         } else {
             read_inode(fd, (dirp->inode & 0x7fffffff), &inode);
             if (S_ISDIR(inode.i_mode)) {
                 ret = 1;
             }
         }
     }
 
     return ret;
 }
 
 static int recurse_dir(int fd, struct ext4_inode *inode, char *dirbuf, int dirsize, int mode)
 {
     unsigned long long *block_list;
     unsigned int num_blocks;
     struct ext4_dir_entry_2 *dirp, *prev_dirp = 0;
     char name[256];
     unsigned int i, leftover_space, is_dir;
     struct ext4_inode tmp_inode;
     int tmp_dirsize;
     char *tmp_dirbuf;
 
     switch (mode) {
         case SANITY_CHECK_PASS:
         case MARK_INODE_NUMS:
         case UPDATE_INODE_NUMS:
             break;
         default:
             critical_error("recurse_dir() called witn unknown mode!\n");
     }
 
     if (dirsize % info.block_size) {
         critical_error("dirsize %d not a multiple of block_size %d.  This is unexpected!\n",
                 dirsize, info.block_size);
     }
 
     num_blocks = dirsize / info.block_size;
 
     block_list = malloc((num_blocks + 1) * sizeof(*block_list));
     if (block_list == 0) {
         critical_error("failed to allocate memory for block_list\n");
     }
 
     if (inode->i_flags & EXT4_EXTENTS_FL) {
         get_block_list_extents(fd, inode, block_list);
     } else {
         /* A directory that requires doubly or triply indirect blocks in huge indeed,
          * and will almost certainly not exist, especially since make_ext4fs only creates
          * directories with extents, and the kernel will too, but check to make sure the
          * directory is not that big and give an error if so.  Our limit is 12 direct blocks,
          * plus block_size/4 singly indirect blocks, which for a filesystem with 4K blocks
          * is a directory 1036 blocks long, or 4,243,456 bytes long!  Assuming an average
          * filename length of 20 (which I think is generous) thats 20 + 8 bytes overhead
          * per entry, or 151,552 entries in the directory!
          */
         if (num_blocks > (info.block_size / 4 + EXT4_NDIR_BLOCKS)) {
             critical_error("Non-extent based directory is too big!\n");
         }
         get_block_list_indirect(fd, inode, block_list);
     }
 
     /* Read in all the blocks for this directory */
     for (i = 0; i < num_blocks; i++) {
         read_block(fd, block_list[i], dirbuf + (i * info.block_size));
     }
 
     dirp = (struct ext4_dir_entry_2 *)dirbuf;
     while (dirp < (struct ext4_dir_entry_2 *)(dirbuf + dirsize)) {
         count++;
         leftover_space = (char *)(dirbuf + dirsize) - (char *)dirp;
         if (((mode == SANITY_CHECK_PASS) || (mode == UPDATE_INODE_NUMS)) &&
             (leftover_space <= 8) && prev_dirp) {
             /* This is a bug in an older version of make_ext4fs, where it
              * didn't properly include the rest of the block in rec_len.
              * Update rec_len on the previous entry to include the rest of
              * the block and exit the loop.
              */
             if (verbose) {
                 printf("fixing up short rec_len for diretory entry for %s\n", name);
             }
             prev_dirp->rec_len += leftover_space;
             break;
         }
 
         if (dirp->inode == 0) {
             /* This is the last entry in the directory */
             break;
         }
 
         strncpy(name, dirp->name, dirp->name_len);
         name[dirp->name_len]='\0';
 
         /* Only recurse on pass UPDATE_INODE_NUMS if the high bit is set.
          * Otherwise, this inode entry has already been updated
          * and we'll do the wrong thing.  Also don't recurse on . or ..,
          * and certainly not on non-directories!
          */
         /* Hrm, looks like filesystems made by fastboot on stingray set the file_type
          * flag, but the lost+found directory has the type set to Unknown, which
          * seems to imply I need to read the inode and get it.
          */
         is_dir = is_entry_dir(fd, dirp, mode);
         if ( is_dir && (strcmp(name, ".") && strcmp(name, "..")) &&
             ((mode == SANITY_CHECK_PASS) || (mode == MARK_INODE_NUMS) ||
               ((mode == UPDATE_INODE_NUMS) && (dirp->inode & 0x80000000))) ) {
             /* A directory!  Recurse! */
             read_inode(fd, dirp->inode & 0x7fffffff, &tmp_inode);
 
             if (!S_ISDIR(tmp_inode.i_mode)) {
                 critical_error("inode %d for name %s does not point to a directory\n",
                         dirp->inode & 0x7fffffff, name);
             }
             if (verbose) {
                 printf("inode %d %s use extents\n", dirp->inode & 0x7fffffff,
                        (tmp_inode.i_flags & EXT4_EXTENTS_FL) ? "does" : "does not");
             }
 
             tmp_dirsize = tmp_inode.i_blocks_lo * INODE_BLOCK_SIZE;
             if (verbose) {
                 printf("dir size = %d bytes\n", tmp_dirsize);
             }
 
             tmp_dirbuf = malloc(tmp_dirsize);
             if (tmp_dirbuf == 0) {
                 critical_error("failed to allocate memory for tmp_dirbuf\n");
             }
 
             recurse_dir(fd, &tmp_inode, tmp_dirbuf, tmp_dirsize, mode);
 
             free(tmp_dirbuf);
         }
 
         if (verbose) {
             if (is_dir) {
                 printf("Directory %s\n", name);
             } else {
                 printf("Non-directory %s\n", name);
             }
         }
 
         /* Process entry based on current mode.  Either set high bit or change inode number */
         if (mode == MARK_INODE_NUMS) {
             dirp->inode |= 0x80000000;
         } else if (mode == UPDATE_INODE_NUMS) {
             if (dirp->inode & 0x80000000) {
                 dirp->inode = compute_new_inum(dirp->inode & 0x7fffffff);
             }
         }
 
         if ((bail_phase == mode) && (bail_loc == 1) && (bail_count == count)) {
             critical_error("Bailing at phase %d, loc 1 and count %d\n", mode, count);
         }
 
         /* Point dirp at the next entry */
         prev_dirp = dirp;
         dirp = (struct ext4_dir_entry_2*)((char *)dirp + dirp->rec_len);
     }
 
     /* Write out all the blocks for this directory */
     for (i = 0; i < num_blocks; i++) {
         write_block(fd, block_list[i], dirbuf + (i * info.block_size));
         if ((bail_phase == mode) && (bail_loc == 2) && (bail_count <= count)) {
             critical_error("Bailing at phase %d, loc 2 and count %d\n", mode, count);
         }
     }
 
     free(block_list);
 
     return 0;
 }
 
 int ext4fixup(char *fsdev)
 {
     return ext4fixup_internal(fsdev, 0, 0, 0, 0, 0);
 }
 
 int ext4fixup_internal(char *fsdev, int v_flag, int n_flag,
                        int stop_phase, int stop_loc, int stop_count)
 {
     int fd;
     struct ext4_inode root_inode;
     unsigned int dirsize;
     char *dirbuf;
 
     if (setjmp(setjmp_env))
         return EXIT_FAILURE; /* Handle a call to longjmp() */
 
     verbose = v_flag;
     no_write = n_flag;
 
     bail_phase = stop_phase;
     bail_loc = stop_loc;
     bail_count = stop_count;
 
     fd = open(fsdev, O_RDWR);
 
     if (fd < 0)
         critical_error_errno("failed to open filesystem image");
 
     read_ext(fd, verbose);
 
     if (info.feat_incompat & EXT4_FEATURE_INCOMPAT_RECOVER) {
         critical_error("Filesystem needs recovery first, mount and unmount to do that\n");
     }
 
     /* Clear the low bit which is set while this tool is in progress.
      * If the tool crashes, it will still be set when we restart.
      * The low bit is set to make the filesystem unmountable while
      * it is being fixed up.  Also allow 0, which means the old ext2
      * size is in use.
      */
     if (((aux_info.sb->s_desc_size & ~1) != sizeof(struct ext2_group_desc)) &&
         ((aux_info.sb->s_desc_size & ~1) != 0))
         critical_error("error: bg_desc_size != sizeof(struct ext2_group_desc)\n");
 
     if ((info.feat_incompat & EXT4_FEATURE_INCOMPAT_FILETYPE) == 0) {
         critical_error("Expected filesystem to have filetype flag set\n");
     }
 
 #if 0 // If we have to fix the directory rec_len issue, we can't use this check
     /* Check to see if the inodes/group is copacetic */
     if (info.inodes_per_blockgroup % (info.block_size/info.inode_size) == 0) {
              /* This filesystem has either already been updated, or was
               * made correctly.
               */
              if (verbose) {
                  printf("%s: filesystem correct, no work to do\n", me);
              }
              exit(0);
     }
 #endif
 
     /* Compute what the new value of inodes_per_blockgroup will be when we're done */
     new_inodes_per_group=EXT4_ALIGN(info.inodes_per_group,(info.block_size/info.inode_size));
 
     read_inode(fd, EXT4_ROOT_INO, &root_inode);
 
     if (!S_ISDIR(root_inode.i_mode)) {
         critical_error("root inode %d does not point to a directory\n", EXT4_ROOT_INO);
     }
     if (verbose) {
         printf("inode %d %s use extents\n", EXT4_ROOT_INO,
                (root_inode.i_flags & EXT4_EXTENTS_FL) ? "does" : "does not");
     }
 
     dirsize = root_inode.i_blocks_lo * INODE_BLOCK_SIZE;
     if (verbose) {
         printf("root dir size = %d bytes\n", dirsize);
     }
 
     dirbuf = malloc(dirsize);
     if (dirbuf == 0) {
         critical_error("failed to allocate memory for dirbuf\n");
     }
 
     /* Perform a sanity check pass first, try to catch any errors that will occur
      * before we actually change anything, so we don't leave a filesystem in a
      * corrupted, unrecoverable state.  Set no_write, make it quiet, and do a recurse
      * pass and a update_superblock pass.  Set flags back to requested state when done.
      * Only perform sanity check if the state is unset.  If the state is _NOT_ unset,
      * then the tool has already been run and interrupted, and it presumably ran and
      * passed sanity checked before it got interrupted.  It is _NOT_ safe to run sanity
      * check if state is unset because it assumes inodes are to be computed using the
      * old inodes/group, but some inode numbers may be updated to the new number.
      */
     if (get_fs_fixup_state(fd) == STATE_UNSET) {
         verbose = 0;
         no_write = 1;
         recurse_dir(fd, &root_inode, dirbuf, dirsize, SANITY_CHECK_PASS);
         update_superblocks_and_bg_desc(fd, STATE_UNSET);
         verbose = v_flag;
         no_write = n_flag;
 
         set_fs_fixup_state(fd, STATE_MARKING_INUMS);
     }
 
     if (get_fs_fixup_state(fd) == STATE_MARKING_INUMS) {
         count = 0; /* Reset debugging counter */
         if (!recurse_dir(fd, &root_inode, dirbuf, dirsize, MARK_INODE_NUMS)) {
             set_fs_fixup_state(fd, STATE_UPDATING_INUMS);
         }
     }
 
     if (get_fs_fixup_state(fd) == STATE_UPDATING_INUMS) {
         count = 0; /* Reset debugging counter */
         if (!recurse_dir(fd, &root_inode, dirbuf, dirsize, UPDATE_INODE_NUMS)) {
             set_fs_fixup_state(fd, STATE_UPDATING_SB);
         }
     }
 
     if (get_fs_fixup_state(fd) == STATE_UPDATING_SB) {
         /* set the new inodes/blockgroup number,
          * and sets the state back to 0.
          */
         if (!update_superblocks_and_bg_desc(fd, STATE_UPDATING_SB)) {
             set_fs_fixup_state(fd, STATE_UNSET);
         }
     }
 
     close(fd);
 
     return 0;
 }
 

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