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super.c

/*
 * e2fsck.c - superblock checks
 * 
 * Copyright (C) 1993, 1994, 1995, 1996, 1997 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif

#ifndef EXT2_SKIP_UUID
#include "uuid/uuid.h"
#endif
#include "e2fsck.h"
#include "problem.h"

#define MIN_CHECK 1
#define MAX_CHECK 2

static void check_super_value(e2fsck_t ctx, const char *descr,
                        unsigned long value, int flags,
                        unsigned long min_val, unsigned long max_val)
{
      struct            problem_context pctx;

      if (((flags & MIN_CHECK) && (value < min_val)) ||
          ((flags & MAX_CHECK) && (value > max_val))) {
            clear_problem_context(&pctx);
            pctx.num = value;
            pctx.str = descr;
            fix_problem(ctx, PR_0_MISC_CORRUPT_SUPER, &pctx);
            ctx->flags |= E2F_FLAG_ABORT; /* never get here! */
      }
}

/*
 * This routine may get stubbed out in special compilations of the
 * e2fsck code..
 */
#ifndef EXT2_SPECIAL_DEVICE_SIZE
errcode_t e2fsck_get_device_size(e2fsck_t ctx)
{
      return (ext2fs_get_device_size(ctx->filesystem_name,
                               EXT2_BLOCK_SIZE(ctx->fs->super),
                               &ctx->num_blocks));
}
#endif

/*
 * helper function to release an inode
 */
struct process_block_struct {
      e2fsck_t    ctx;
      char        *buf;
      struct problem_context *pctx;
      int         truncating;
      int         truncate_offset;
      blk_t       truncate_block;
      int         truncated_blocks;
      int         abort;
      errcode_t   errcode;
};

static int release_inode_block(ext2_filsys fs,
                         blk_t      *block_nr,
                         int blockcnt,
                         void *priv_data)
{
      struct process_block_struct *pb;
      e2fsck_t          ctx;
      struct problem_context  *pctx;
      blk_t             blk = *block_nr;
      int               retval = 0;

      pb = (struct process_block_struct *) priv_data;
      ctx = pb->ctx;
      pctx = pb->pctx;

      pctx->blk = blk;
      pctx->blkcount = blockcnt;

      if (HOLE_BLKADDR(blk))
            return 0;

      if ((blk < fs->super->s_first_data_block) ||
          (blk >= fs->super->s_blocks_count)) {
            fix_problem(ctx, PR_0_ORPHAN_ILLEGAL_BLOCK_NUM, pctx);
      return_abort:
            pb->abort = 1;
            return BLOCK_ABORT;
      }

      if (!ext2fs_test_block_bitmap(fs->block_map, blk)) {
            fix_problem(ctx, PR_0_ORPHAN_ALREADY_CLEARED_BLOCK, pctx);
            goto return_abort;
      }

      /*
       * If we are deleting an orphan, then we leave the fields alone.
       * If we are truncating an orphan, then update the inode fields
       * and clean up any partial block data.
       */
      if (pb->truncating) {
            /*
             * We only remove indirect blocks if they are
             * completely empty.
             */
            if (blockcnt < 0) {
                  int   i, limit;
                  blk_t *bp;
                  
                  pb->errcode = io_channel_read_blk(fs->io, blk, 1,
                                          pb->buf);
                  if (pb->errcode)
                        goto return_abort;

                  limit = fs->blocksize >> 2;
                  for (i = 0, bp = (blk_t *) pb->buf;
                       i < limit;    i++, bp++)
                        if (*bp)
                              return 0;
            }
            /*
             * We don't remove direct blocks until we've reached
             * the truncation block.
             */
            if (blockcnt >= 0 && blockcnt < pb->truncate_block)
                  return 0;
            /*
             * If part of the last block needs truncating, we do
             * it here.
             */
            if ((blockcnt == pb->truncate_block) && pb->truncate_offset) {
                  pb->errcode = io_channel_read_blk(fs->io, blk, 1,
                                          pb->buf);
                  if (pb->errcode)
                        goto return_abort;
                  memset(pb->buf + pb->truncate_offset, 0,
                         fs->blocksize - pb->truncate_offset);
                  pb->errcode = io_channel_write_blk(fs->io, blk, 1,
                                           pb->buf);
                  if (pb->errcode)
                        goto return_abort;
            }
            pb->truncated_blocks++;
            *block_nr = 0;
            retval |= BLOCK_CHANGED;
      }
      
      ext2fs_unmark_block_bitmap(fs->block_map, blk);
      fs->group_desc[ext2fs_group_of_blk(fs, blk)].bg_free_blocks_count++;
      fs->super->s_free_blocks_count++;
      
      return retval;
}
            
/*
 * This function releases an inode.  Returns 1 if an inconsistency was
 * found.  If the inode has a link count, then it is being truncated and
 * not deleted.
 */
static int release_inode_blocks(e2fsck_t ctx, ext2_ino_t ino,
                        struct ext2_inode *inode, char *block_buf,
                        struct problem_context *pctx)
{
      ext2_filsys             fs = ctx->fs;
      errcode_t               retval;
      struct process_block_struct   pb;

      if (!ext2fs_inode_has_valid_blocks(inode))
            return 0;

      pb.buf = block_buf + 3 * ctx->fs->blocksize;
      pb.ctx = ctx;
      pb.abort = 0;
      pb.errcode = 0;
      pb.pctx = pctx;
      if (inode->i_links_count) {
            pb.truncating = 1;
            pb.truncate_block = (blk_t)
                  ((((long long)inode->i_size_high << 32) +
                    inode->i_size + fs->blocksize - 1) /
                   fs->blocksize);
            pb.truncate_offset = inode->i_size % fs->blocksize;
      } else {
            pb.truncating = 0;
            pb.truncate_block = 0;
            pb.truncate_offset = 0;
      }
      pb.truncated_blocks = 0;
      retval = ext2fs_block_iterate(fs, ino, BLOCK_FLAG_DEPTH_TRAVERSE, 
                              block_buf, release_inode_block, &pb);
      if (retval) {
            com_err("release_inode_blocks", retval,
                  _("while calling ext2fs_block_iterate for inode %d"),
                  ino);
            return 1;
      }
      if (pb.abort)
            return 1;

      /* Refresh the inode since ext2fs_block_iterate may have changed it */
      e2fsck_read_inode(ctx, ino, inode, "release_inode_blocks");

      if (pb.truncated_blocks)
            inode->i_blocks -= pb.truncated_blocks *
                  (fs->blocksize / 512);

      ext2fs_mark_bb_dirty(fs);
      return 0;
}

/*
 * This function releases all of the orphan inodes.  It returns 1 if
 * it hit some error, and 0 on success.
 */
static int release_orphan_inodes(e2fsck_t ctx)
{
      ext2_filsys fs = ctx->fs;
      int group;
      ext2_ino_t  ino, next_ino;
      struct ext2_inode inode;
      struct problem_context pctx;
      char *block_buf;

      if ((ino = fs->super->s_last_orphan) == 0)
            return 0;

      /*
       * Win or lose, we won't be using the head of the orphan inode
       * list again.
       */
      fs->super->s_last_orphan = 0;
      ext2fs_mark_super_dirty(fs);

      /*
       * If the filesystem contains errors, don't run the orphan
       * list, since the orphan list can't be trusted; and we're
       * going to be running a full e2fsck run anyway...
       */
      if (fs->super->s_state & EXT2_ERROR_FS)
            return 0;
      
      if ((ino < EXT2_FIRST_INODE(fs->super)) ||
          (ino > fs->super->s_inodes_count)) {
            clear_problem_context(&pctx);
            pctx.ino = ino;
            fix_problem(ctx, PR_0_ORPHAN_ILLEGAL_HEAD_INODE, &pctx);
            return 1;
      }

      block_buf = (char *) e2fsck_allocate_memory(ctx, fs->blocksize * 4,
                                        "block iterate buffer");
      e2fsck_read_bitmaps(ctx);
      
      while (ino) {
            e2fsck_read_inode(ctx, ino, &inode, "release_orphan_inodes");
            clear_problem_context(&pctx);
            pctx.ino = ino;
            pctx.inode = &inode;
            pctx.str = inode.i_links_count ? _("Truncating") :
                  _("Clearing");

            fix_problem(ctx, PR_0_ORPHAN_CLEAR_INODE, &pctx);

            next_ino = inode.i_dtime;
            if (next_ino &&
                ((next_ino < EXT2_FIRST_INODE(fs->super)) ||
                 (next_ino > fs->super->s_inodes_count))) {
                  pctx.ino = next_ino;
                  fix_problem(ctx, PR_0_ORPHAN_ILLEGAL_INODE, &pctx);
                  goto return_abort;
            }

            if (release_inode_blocks(ctx, ino, &inode, block_buf, &pctx))
                  goto return_abort;

            if (!inode.i_links_count) {
                  ext2fs_unmark_inode_bitmap(fs->inode_map, ino);
                  ext2fs_mark_ib_dirty(fs);
                  group = ext2fs_group_of_ino(fs, ino);
                  fs->group_desc[group].bg_free_inodes_count++;
                  fs->super->s_free_inodes_count++;
                  if (LINUX_S_ISDIR(inode.i_mode))
                        fs->group_desc[group].bg_used_dirs_count--;
                  
                  inode.i_dtime = time(0);
            }
            e2fsck_write_inode(ctx, ino, &inode, "delete_file");
            ino = next_ino;
      }
      ext2fs_free_mem((void **) &block_buf);
      return 0;
return_abort:
      ext2fs_free_mem((void **) &block_buf);
      return 1;
}


void check_super_block(e2fsck_t ctx)
{
      ext2_filsys fs = ctx->fs;
      blk_t first_block, last_block;
      struct ext2_super_block *sb = fs->super;
      blk_t blocks_per_group = fs->super->s_blocks_per_group;
      int   inodes_per_block;
      dgrp_t      i;
      blk_t should_be;
      struct problem_context  pctx;
      
      inodes_per_block = (EXT2_BLOCK_SIZE(fs->super) /
                      EXT2_INODE_SIZE(fs->super));

      ctx->invalid_inode_bitmap_flag = (int *) e2fsck_allocate_memory(ctx,
             sizeof(int) * fs->group_desc_count, "invalid_inode_bitmap");
      ctx->invalid_block_bitmap_flag = (int *) e2fsck_allocate_memory(ctx,
             sizeof(int) * fs->group_desc_count, "invalid_block_bitmap");
      ctx->invalid_inode_table_flag = (int *) e2fsck_allocate_memory(ctx,
            sizeof(int) * fs->group_desc_count, "invalid_inode_table");
            
      clear_problem_context(&pctx);

      /*
       * Verify the super block constants...
       */
      check_super_value(ctx, "inodes_count", sb->s_inodes_count,
                    MIN_CHECK, 1, 0);
      check_super_value(ctx, "blocks_count", sb->s_blocks_count,
                    MIN_CHECK, 1, 0);
      check_super_value(ctx, "first_data_block", sb->s_first_data_block,
                    MAX_CHECK, 0, sb->s_blocks_count);
      check_super_value(ctx, "log_frag_size", sb->s_log_frag_size,
                    MAX_CHECK, 0, 2);
      check_super_value(ctx, "log_block_size", sb->s_log_block_size,
                    MIN_CHECK | MAX_CHECK, sb->s_log_frag_size,
                    2);
      check_super_value(ctx, "frags_per_group", sb->s_frags_per_group,
                    MIN_CHECK | MAX_CHECK, sb->s_blocks_per_group,
                    8 * EXT2_BLOCK_SIZE(sb));
      check_super_value(ctx, "blocks_per_group", sb->s_blocks_per_group,
                    MIN_CHECK | MAX_CHECK, 8, 8 * EXT2_BLOCK_SIZE(sb));
      check_super_value(ctx, "inodes_per_group", sb->s_inodes_per_group,
                    MIN_CHECK | MAX_CHECK, inodes_per_block,
                    inodes_per_block * (blocks_per_group-4));
      check_super_value(ctx, "r_blocks_count", sb->s_r_blocks_count,
                    MAX_CHECK, 0, sb->s_blocks_count / 4);

      if (!ctx->num_blocks) {
            pctx.errcode = e2fsck_get_device_size(ctx);
            if (pctx.errcode && pctx.errcode != EXT2_ET_UNIMPLEMENTED) {
                  fix_problem(ctx, PR_0_GETSIZE_ERROR, &pctx);
                  ctx->flags |= E2F_FLAG_ABORT;
                  return;
            }
            if ((pctx.errcode != EXT2_ET_UNIMPLEMENTED) &&
                (ctx->num_blocks < sb->s_blocks_count)) {
                  pctx.blk = sb->s_blocks_count;
                  pctx.blk2 = ctx->num_blocks;
                  if (fix_problem(ctx, PR_0_FS_SIZE_WRONG, &pctx)) {
                        ctx->flags |= E2F_FLAG_ABORT;
                        return;
                  }
            }
      }

      if (sb->s_log_block_size != sb->s_log_frag_size) {
            pctx.blk = EXT2_BLOCK_SIZE(sb);
            pctx.blk2 = EXT2_FRAG_SIZE(sb);
            fix_problem(ctx, PR_0_NO_FRAGMENTS, &pctx);
            ctx->flags |= E2F_FLAG_ABORT;
            return;
      }

      should_be = sb->s_frags_per_group >>
            (sb->s_log_block_size - sb->s_log_frag_size);         
      if (sb->s_blocks_per_group != should_be) {
            pctx.blk = sb->s_blocks_per_group;
            pctx.blk2 = should_be;
            fix_problem(ctx, PR_0_BLOCKS_PER_GROUP, &pctx);
            ctx->flags |= E2F_FLAG_ABORT;
            return;
      }

      should_be = (sb->s_log_block_size == 0) ? 1 : 0;
      if (sb->s_first_data_block != should_be) {
            pctx.blk = sb->s_first_data_block;
            pctx.blk2 = should_be;
            fix_problem(ctx, PR_0_FIRST_DATA_BLOCK, &pctx);
            ctx->flags |= E2F_FLAG_ABORT;
            return;
      }

      should_be = sb->s_inodes_per_group * fs->group_desc_count;
      if (sb->s_inodes_count != should_be) {
            pctx.ino = sb->s_inodes_count;
            pctx.ino2 = should_be;
            if (fix_problem(ctx, PR_0_INODE_COUNT_WRONG, &pctx)) {
                  sb->s_inodes_count = should_be;
                  ext2fs_mark_super_dirty(fs);
            }
      }

      /*
       * Verify the group descriptors....
       */
      first_block =  fs->super->s_first_data_block;
      last_block = first_block + blocks_per_group;

      for (i = 0; i < fs->group_desc_count; i++) {
            pctx.group = i;
            
            if (i == fs->group_desc_count - 1)
                  last_block = fs->super->s_blocks_count;
            if ((fs->group_desc[i].bg_block_bitmap < first_block) ||
                (fs->group_desc[i].bg_block_bitmap >= last_block)) {
                  pctx.blk = fs->group_desc[i].bg_block_bitmap;
                  if (fix_problem(ctx, PR_0_BB_NOT_GROUP, &pctx))
                        fs->group_desc[i].bg_block_bitmap = 0;
            }
            if (fs->group_desc[i].bg_block_bitmap == 0) {
                  ctx->invalid_block_bitmap_flag[i]++;
                  ctx->invalid_bitmaps++;
            }
            if ((fs->group_desc[i].bg_inode_bitmap < first_block) ||
                (fs->group_desc[i].bg_inode_bitmap >= last_block)) {
                  pctx.blk = fs->group_desc[i].bg_inode_bitmap;
                  if (fix_problem(ctx, PR_0_IB_NOT_GROUP, &pctx))
                        fs->group_desc[i].bg_inode_bitmap = 0;
            }
            if (fs->group_desc[i].bg_inode_bitmap == 0) {
                  ctx->invalid_inode_bitmap_flag[i]++;
                  ctx->invalid_bitmaps++;
            }
            if ((fs->group_desc[i].bg_inode_table < first_block) ||
                ((fs->group_desc[i].bg_inode_table +
                  fs->inode_blocks_per_group - 1) >= last_block)) {
                  pctx.blk = fs->group_desc[i].bg_inode_table;
                  if (fix_problem(ctx, PR_0_ITABLE_NOT_GROUP, &pctx))
                        fs->group_desc[i].bg_inode_table = 0;
            }
            if (fs->group_desc[i].bg_inode_table == 0) {
                  ctx->invalid_inode_table_flag[i]++;
                  ctx->invalid_bitmaps++;
            }
            first_block += fs->super->s_blocks_per_group;
            last_block += fs->super->s_blocks_per_group;
      }
      /*
       * If we have invalid bitmaps, set the error state of the
       * filesystem.
       */
      if (ctx->invalid_bitmaps && !(ctx->options & E2F_OPT_READONLY)) {
            fs->super->s_state &= ~EXT2_VALID_FS;
            ext2fs_mark_super_dirty(fs);
      }

      clear_problem_context(&pctx);
      
#ifndef EXT2_SKIP_UUID
      /*
       * If the UUID field isn't assigned, assign it.
       */
      if (!(ctx->options & E2F_OPT_READONLY) && uuid_is_null(sb->s_uuid)) {
            if (fix_problem(ctx, PR_0_ADD_UUID, &pctx)) {
                  uuid_generate(sb->s_uuid);
                  ext2fs_mark_super_dirty(fs);
            }
      }
#endif
      
      /*
       * For the Hurd, check to see if the filetype option is set,
       * since it doesn't support it.
       */
      if (!(ctx->options & E2F_OPT_READONLY) &&
          fs->super->s_creator_os == EXT2_OS_HURD &&
          (fs->super->s_feature_incompat &
           EXT2_FEATURE_INCOMPAT_FILETYPE)) {
            if (fix_problem(ctx, PR_0_HURD_CLEAR_FILETYPE, &pctx)) {
                  fs->super->s_feature_incompat &=
                        ~EXT2_FEATURE_INCOMPAT_FILETYPE;
                  ext2fs_mark_super_dirty(fs);

            }
      }

      /*
       * If we have any of the compatibility flags set, we need to have a
       * revision 1 filesystem.  Most kernels will not check the flags on
       * a rev 0 filesystem and we may have corruption issues because of
       * the incompatible changes to the filesystem.
       */
      if (!(ctx->options & E2F_OPT_READONLY) &&
          fs->super->s_rev_level == EXT2_GOOD_OLD_REV &&
          (fs->super->s_feature_compat ||
           fs->super->s_feature_ro_compat ||
           fs->super->s_feature_incompat) &&
          fix_problem(ctx, PR_0_FS_REV_LEVEL, &pctx)) {
            ext2fs_update_dynamic_rev(fs);
            ext2fs_mark_super_dirty(fs);
      }

      /*
       * Clean up any orphan inodes, if present.
       */
      if (!(ctx->options & E2F_OPT_READONLY) && release_orphan_inodes(ctx)) {
            fs->super->s_state &= ~EXT2_VALID_FS;
            ext2fs_mark_super_dirty(fs);
      }

      /*
       * Move the ext3 journal file, if necessary.
       */
      e2fsck_move_ext3_journal(ctx);
      return;
}



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