/*
 * 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 ((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;
	}
	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;
				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;
				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;
				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);
	}

	return;
}