fs/udf/balloc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * balloc.c
  *
  * PURPOSE
  *	Block allocation handling routines for the OSTA-UDF(tm) filesystem.
  *
  * COPYRIGHT
  *  (C) 1999-2001 Ben Fennema
  *  (C) 1999 Stelias Computing Inc
  *
  * HISTORY
  *
  *  02/24/99 blf  Created.
  *
  */

 #include "udfdecl.h"

 #include <linux/bitops.h>
 #include <linux/overflow.h>

 #include "udf_i.h"
 #include "udf_sb.h"

 #define udf_clear_bit	__test_and_clear_bit_le
 #define udf_set_bit	__test_and_set_bit_le
 #define udf_test_bit	test_bit_le
 #define udf_find_next_one_bit	find_next_bit_le

 static int read_block_bitmap(struct super_block *sb,
 			     struct udf_bitmap *bitmap, unsigned int block,
 			     unsigned long bitmap_nr)
 {
 	struct buffer_head *bh = NULL;
 	int i;
 	int max_bits, off, count;
 	struct kernel_lb_addr loc;

 	loc.logicalBlockNum = bitmap->s_extPosition;
 	loc.partitionReferenceNum = UDF_SB(sb)->s_partition;

 	bh = sb_bread(sb, udf_get_lb_pblock(sb, &loc, block));
 	bitmap->s_block_bitmap[bitmap_nr] = bh;
 	if (!bh)
 		return -EIO;

 	/* Check consistency of Space Bitmap buffer. */
 	max_bits = sb->s_blocksize * 8;
 	if (!bitmap_nr) {
 		off = sizeof(struct spaceBitmapDesc) << 3;
 		count = min(max_bits - off, bitmap->s_nr_groups);
 	} else {
 		/*
 		 * Rough check if bitmap number is too big to have any bitmap
  		 * blocks reserved.
 		 */
 		if (bitmap_nr >
 		    (bitmap->s_nr_groups >> (sb->s_blocksize_bits + 3)) + 2)
 			return 0;
 		off = 0;
 		count = bitmap->s_nr_groups - bitmap_nr * max_bits +
 				(sizeof(struct spaceBitmapDesc) << 3);
 		count = min(count, max_bits);
 	}

 	for (i = 0; i < count; i++)
 		if (udf_test_bit(i + off, bh->b_data)) {
 			bitmap->s_block_bitmap[bitmap_nr] =
 							ERR_PTR(-EFSCORRUPTED);
 			brelse(bh);
 			return -EFSCORRUPTED;
 		}
 	return 0;
 }

 static int load_block_bitmap(struct super_block *sb,
 			     struct udf_bitmap *bitmap,
 			     unsigned int block_group)
 {
 	int retval = 0;
 	int nr_groups = bitmap->s_nr_groups;

 	if (block_group >= nr_groups) {
 		udf_debug("block_group (%u) > nr_groups (%d)\n",
 			  block_group, nr_groups);
 	}

 	if (bitmap->s_block_bitmap[block_group]) {
 		/*
 		 * The bitmap failed verification in the past. No point in
 		 * trying again.
 		 */
 		if (IS_ERR(bitmap->s_block_bitmap[block_group]))
 			return PTR_ERR(bitmap->s_block_bitmap[block_group]);
 		return block_group;
 	}

 	retval = read_block_bitmap(sb, bitmap, block_group, block_group);
 	if (retval < 0)
 		return retval;

 	return block_group;
 }

 static void udf_add_free_space(struct super_block *sb, u16 partition, u32 cnt)
 {
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	struct logicalVolIntegrityDesc *lvid;

 	if (!sbi->s_lvid_bh)
 		return;

 	lvid = (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
 	le32_add_cpu(&lvid->freeSpaceTable[partition], cnt);
 	udf_updated_lvid(sb);
 }

 static void udf_bitmap_free_blocks(struct super_block *sb,
 				   struct udf_bitmap *bitmap,
 				   struct kernel_lb_addr *bloc,
 				   uint32_t offset,
 				   uint32_t count)
 {
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	struct buffer_head *bh = NULL;
 	unsigned long block;
 	unsigned long block_group;
 	unsigned long bit;
 	unsigned long i;
 	int bitmap_nr;
 	unsigned long overflow;

 	mutex_lock(&sbi->s_alloc_mutex);
 	/* We make sure this cannot overflow when mounting the filesystem */
 	block = bloc->logicalBlockNum + offset +
 		(sizeof(struct spaceBitmapDesc) << 3);
 	do {
 		overflow = 0;
 		block_group = block >> (sb->s_blocksize_bits + 3);
 		bit = block % (sb->s_blocksize << 3);

 		/*
 		* Check to see if we are freeing blocks across a group boundary.
 		*/
 		if (bit + count > (sb->s_blocksize << 3)) {
 			overflow = bit + count - (sb->s_blocksize << 3);
 			count -= overflow;
 		}
 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 		if (bitmap_nr < 0)
 			goto error_return;

 		bh = bitmap->s_block_bitmap[bitmap_nr];
 		for (i = 0; i < count; i++) {
 			if (udf_set_bit(bit + i, bh->b_data)) {
 				udf_debug("bit %lu already set\n", bit + i);
 				udf_debug("byte=%2x\n",
 					  ((__u8 *)bh->b_data)[(bit + i) >> 3]);
 			}
 		}
 		udf_add_free_space(sb, sbi->s_partition, count);
 		mark_buffer_dirty(bh);
 		if (overflow) {
 			block += count;
 			count = overflow;
 		}
 	} while (overflow);

 error_return:
 	mutex_unlock(&sbi->s_alloc_mutex);
 }

 static int udf_bitmap_prealloc_blocks(struct super_block *sb,
 				      struct udf_bitmap *bitmap,
 				      uint16_t partition, uint32_t first_block,
 				      uint32_t block_count)
 {
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	int alloc_count = 0;
 	int bit, block, block_group;
 	int bitmap_nr;
 	struct buffer_head *bh;
 	__u32 part_len;

 	mutex_lock(&sbi->s_alloc_mutex);
 	part_len = sbi->s_partmaps[partition].s_partition_len;
 	if (first_block >= part_len)
 		goto out;

 	if (first_block + block_count > part_len)
 		block_count = part_len - first_block;

 	do {
 		block = first_block + (sizeof(struct spaceBitmapDesc) << 3);
 		block_group = block >> (sb->s_blocksize_bits + 3);

 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 		if (bitmap_nr < 0)
 			goto out;
 		bh = bitmap->s_block_bitmap[bitmap_nr];

 		bit = block % (sb->s_blocksize << 3);

 		while (bit < (sb->s_blocksize << 3) && block_count > 0) {
 			if (!udf_clear_bit(bit, bh->b_data))
 				goto out;
 			block_count--;
 			alloc_count++;
 			bit++;
 			block++;
 		}
 		mark_buffer_dirty(bh);
 	} while (block_count > 0);

 out:
 	udf_add_free_space(sb, partition, -alloc_count);
 	mutex_unlock(&sbi->s_alloc_mutex);
 	return alloc_count;
 }

 static udf_pblk_t udf_bitmap_new_block(struct super_block *sb,
 				struct udf_bitmap *bitmap, uint16_t partition,
 				uint32_t goal, int *err)
 {
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	int newbit, bit = 0;
 	udf_pblk_t block;
 	int block_group, group_start;
 	int end_goal, nr_groups, bitmap_nr, i;
 	struct buffer_head *bh = NULL;
 	char *ptr;
 	udf_pblk_t newblock = 0;

 	*err = -ENOSPC;
 	mutex_lock(&sbi->s_alloc_mutex);

 repeat:
 	if (goal >= sbi->s_partmaps[partition].s_partition_len)
 		goal = 0;

 	nr_groups = bitmap->s_nr_groups;
 	block = goal + (sizeof(struct spaceBitmapDesc) << 3);
 	block_group = block >> (sb->s_blocksize_bits + 3);
 	group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

 	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 	if (bitmap_nr < 0)
 		goto error_return;
 	bh = bitmap->s_block_bitmap[bitmap_nr];
 	ptr = memscan((char *)bh->b_data + group_start, 0xFF,
 		      sb->s_blocksize - group_start);

 	if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
 		bit = block % (sb->s_blocksize << 3);
 		if (udf_test_bit(bit, bh->b_data))
 			goto got_block;

 		end_goal = (bit + 63) & ~63;
 		bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
 		if (bit < end_goal)
 			goto got_block;

 		ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF,
 			      sb->s_blocksize - ((bit + 7) >> 3));
 		newbit = (ptr - ((char *)bh->b_data)) << 3;
 		if (newbit < sb->s_blocksize << 3) {
 			bit = newbit;
 			goto search_back;
 		}

 		newbit = udf_find_next_one_bit(bh->b_data,
 					       sb->s_blocksize << 3, bit);
 		if (newbit < sb->s_blocksize << 3) {
 			bit = newbit;
 			goto got_block;
 		}
 	}

 	for (i = 0; i < (nr_groups * 2); i++) {
 		block_group++;
 		if (block_group >= nr_groups)
 			block_group = 0;
 		group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

 		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
 		if (bitmap_nr < 0)
 			goto error_return;
 		bh = bitmap->s_block_bitmap[bitmap_nr];
 		if (i < nr_groups) {
 			ptr = memscan((char *)bh->b_data + group_start, 0xFF,
 				      sb->s_blocksize - group_start);
 			if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
 				bit = (ptr - ((char *)bh->b_data)) << 3;
 				break;
 			}
 		} else {
 			bit = udf_find_next_one_bit(bh->b_data,
 						    sb->s_blocksize << 3,
 						    group_start << 3);
 			if (bit < sb->s_blocksize << 3)
 				break;
 		}
 	}
 	if (i >= (nr_groups * 2)) {
 		mutex_unlock(&sbi->s_alloc_mutex);
 		return newblock;
 	}
 	if (bit < sb->s_blocksize << 3)
 		goto search_back;
 	else
 		bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3,
 					    group_start << 3);
 	if (bit >= sb->s_blocksize << 3) {
 		mutex_unlock(&sbi->s_alloc_mutex);
 		return 0;
 	}

 search_back:
 	i = 0;
 	while (i < 7 && bit > (group_start << 3) &&
 	       udf_test_bit(bit - 1, bh->b_data)) {
 		++i;
 		--bit;
 	}

 got_block:
 	newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
 		(sizeof(struct spaceBitmapDesc) << 3);

 	if (newblock >= sbi->s_partmaps[partition].s_partition_len) {
 		/*
 		 * Ran off the end of the bitmap, and bits following are
 		 * non-compliant (not all zero)
 		 */
 		udf_err(sb, "bitmap for partition %d corrupted (block %u marked"
 			" as free, partition length is %u)\n", partition,
 			newblock, sbi->s_partmaps[partition].s_partition_len);
 		goto error_return;
 	}

 	if (!udf_clear_bit(bit, bh->b_data)) {
 		udf_debug("bit already cleared for block %d\n", bit);
 		goto repeat;
 	}

 	mark_buffer_dirty(bh);

 	udf_add_free_space(sb, partition, -1);
 	mutex_unlock(&sbi->s_alloc_mutex);
 	*err = 0;
 	return newblock;

 error_return:
 	*err = -EIO;
 	mutex_unlock(&sbi->s_alloc_mutex);
 	return 0;
 }

 static void udf_table_free_blocks(struct super_block *sb,
 				  struct inode *table,
 				  struct kernel_lb_addr *bloc,
 				  uint32_t offset,
 				  uint32_t count)
 {
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	uint32_t start, end;
 	uint32_t elen;
 	struct kernel_lb_addr eloc;
 	struct extent_position oepos, epos;
 	int8_t etype;
 	struct udf_inode_info *iinfo;

 	mutex_lock(&sbi->s_alloc_mutex);
 	iinfo = UDF_I(table);
 	udf_add_free_space(sb, sbi->s_partition, count);

 	start = bloc->logicalBlockNum + offset;
 	end = bloc->logicalBlockNum + offset + count - 1;

 	epos.offset = oepos.offset = sizeof(struct unallocSpaceEntry);
 	elen = 0;
 	epos.block = oepos.block = iinfo->i_location;
 	epos.bh = oepos.bh = NULL;

 	while (count &&
 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
 		if (((eloc.logicalBlockNum +
 			(elen >> sb->s_blocksize_bits)) == start)) {
 			if ((0x3FFFFFFF - elen) <
 					(count << sb->s_blocksize_bits)) {
 				uint32_t tmp = ((0x3FFFFFFF - elen) >>
 							sb->s_blocksize_bits);
 				count -= tmp;
 				start += tmp;
 				elen = (etype << 30) |
 					(0x40000000 - sb->s_blocksize);
 			} else {
 				elen = (etype << 30) |
 					(elen +
 					(count << sb->s_blocksize_bits));
 				start += count;
 				count = 0;
 			}
 			udf_write_aext(table, &oepos, &eloc, elen, 1);
 		} else if (eloc.logicalBlockNum == (end + 1)) {
 			if ((0x3FFFFFFF - elen) <
 					(count << sb->s_blocksize_bits)) {
 				uint32_t tmp = ((0x3FFFFFFF - elen) >>
 						sb->s_blocksize_bits);
 				count -= tmp;
 				end -= tmp;
 				eloc.logicalBlockNum -= tmp;
 				elen = (etype << 30) |
 					(0x40000000 - sb->s_blocksize);
 			} else {
 				eloc.logicalBlockNum = start;
 				elen = (etype << 30) |
 					(elen +
 					(count << sb->s_blocksize_bits));
 				end -= count;
 				count = 0;
 			}
 			udf_write_aext(table, &oepos, &eloc, elen, 1);
 		}

 		if (epos.bh != oepos.bh) {
 			oepos.block = epos.block;
 			brelse(oepos.bh);
 			get_bh(epos.bh);
 			oepos.bh = epos.bh;
 			oepos.offset = 0;
 		} else {
 			oepos.offset = epos.offset;
 		}
 	}

 	if (count) {
 		/*
 		 * NOTE: we CANNOT use udf_add_aext here, as it can try to
 		 * allocate a new block, and since we hold the super block
 		 * lock already very bad things would happen :)
 		 *
 		 * We copy the behavior of udf_add_aext, but instead of
 		 * trying to allocate a new block close to the existing one,
 		 * we just steal a block from the extent we are trying to add.
 		 *
 		 * It would be nice if the blocks were close together, but it
 		 * isn't required.
 		 */

 		int adsize;

 		eloc.logicalBlockNum = start;
 		elen = EXT_RECORDED_ALLOCATED |
 			(count << sb->s_blocksize_bits);

 		if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 			adsize = sizeof(struct short_ad);
 		else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 			adsize = sizeof(struct long_ad);
 		else {
 			brelse(oepos.bh);
 			brelse(epos.bh);
 			goto error_return;
 		}

 		if (epos.offset + (2 * adsize) > sb->s_blocksize) {
 			/* Steal a block from the extent being free'd */
 			udf_setup_indirect_aext(table, eloc.logicalBlockNum,
 						&epos);

 			eloc.logicalBlockNum++;
 			elen -= sb->s_blocksize;
 		}

 		/* It's possible that stealing the block emptied the extent */
 		if (elen)
 			__udf_add_aext(table, &epos, &eloc, elen, 1);
 	}

 	brelse(epos.bh);
 	brelse(oepos.bh);

 error_return:
 	mutex_unlock(&sbi->s_alloc_mutex);
 	return;
 }

 static int udf_table_prealloc_blocks(struct super_block *sb,
 				     struct inode *table, uint16_t partition,
 				     uint32_t first_block, uint32_t block_count)
 {
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	int alloc_count = 0;
 	uint32_t elen, adsize;
 	struct kernel_lb_addr eloc;
 	struct extent_position epos;
 	int8_t etype = -1;
 	struct udf_inode_info *iinfo;

 	if (first_block >= sbi->s_partmaps[partition].s_partition_len)
 		return 0;

 	iinfo = UDF_I(table);
 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(struct short_ad);
 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(struct long_ad);
 	else
 		return 0;

 	mutex_lock(&sbi->s_alloc_mutex);
 	epos.offset = sizeof(struct unallocSpaceEntry);
 	epos.block = iinfo->i_location;
 	epos.bh = NULL;
 	eloc.logicalBlockNum = 0xFFFFFFFF;

 	while (first_block != eloc.logicalBlockNum &&
 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
 		udf_debug("eloc=%u, elen=%u, first_block=%u\n",
 			  eloc.logicalBlockNum, elen, first_block);
 		; /* empty loop body */
 	}

 	if (first_block == eloc.logicalBlockNum) {
 		epos.offset -= adsize;

 		alloc_count = (elen >> sb->s_blocksize_bits);
 		if (alloc_count > block_count) {
 			alloc_count = block_count;
 			eloc.logicalBlockNum += alloc_count;
 			elen -= (alloc_count << sb->s_blocksize_bits);
 			udf_write_aext(table, &epos, &eloc,
 					(etype << 30) | elen, 1);
 		} else
 			udf_delete_aext(table, epos);
 	} else {
 		alloc_count = 0;
 	}

 	brelse(epos.bh);

 	if (alloc_count)
 		udf_add_free_space(sb, partition, -alloc_count);
 	mutex_unlock(&sbi->s_alloc_mutex);
 	return alloc_count;
 }

 static udf_pblk_t udf_table_new_block(struct super_block *sb,
 			       struct inode *table, uint16_t partition,
 			       uint32_t goal, int *err)
 {
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	uint32_t spread = 0xFFFFFFFF, nspread = 0xFFFFFFFF;
 	udf_pblk_t newblock = 0;
 	uint32_t adsize;
 	uint32_t elen, goal_elen = 0;
 	struct kernel_lb_addr eloc, goal_eloc;
 	struct extent_position epos, goal_epos;
 	int8_t etype;
 	struct udf_inode_info *iinfo = UDF_I(table);

 	*err = -ENOSPC;

 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(struct short_ad);
 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(struct long_ad);
 	else
 		return newblock;

 	mutex_lock(&sbi->s_alloc_mutex);
 	if (goal >= sbi->s_partmaps[partition].s_partition_len)
 		goal = 0;

 	/* We search for the closest matching block to goal. If we find
 	   a exact hit, we stop. Otherwise we keep going till we run out
 	   of extents. We store the buffer_head, bloc, and extoffset
 	   of the current closest match and use that when we are done.
 	 */
 	epos.offset = sizeof(struct unallocSpaceEntry);
 	epos.block = iinfo->i_location;
 	epos.bh = goal_epos.bh = NULL;

 	while (spread &&
 	       (etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
 		if (goal >= eloc.logicalBlockNum) {
 			if (goal < eloc.logicalBlockNum +
 					(elen >> sb->s_blocksize_bits))
 				nspread = 0;
 			else
 				nspread = goal - eloc.logicalBlockNum -
 					(elen >> sb->s_blocksize_bits);
 		} else {
 			nspread = eloc.logicalBlockNum - goal;
 		}

 		if (nspread < spread) {
 			spread = nspread;
 			if (goal_epos.bh != epos.bh) {
 				brelse(goal_epos.bh);
 				goal_epos.bh = epos.bh;
 				get_bh(goal_epos.bh);
 			}
 			goal_epos.block = epos.block;
 			goal_epos.offset = epos.offset - adsize;
 			goal_eloc = eloc;
 			goal_elen = (etype << 30) | elen;
 		}
 	}

 	brelse(epos.bh);

 	if (spread == 0xFFFFFFFF) {
 		brelse(goal_epos.bh);
 		mutex_unlock(&sbi->s_alloc_mutex);
 		return 0;
 	}

 	/* Only allocate blocks from the beginning of the extent.
 	   That way, we only delete (empty) extents, never have to insert an
 	   extent because of splitting */
 	/* This works, but very poorly.... */

 	newblock = goal_eloc.logicalBlockNum;
 	goal_eloc.logicalBlockNum++;
 	goal_elen -= sb->s_blocksize;

 	if (goal_elen)
 		udf_write_aext(table, &goal_epos, &goal_eloc, goal_elen, 1);
 	else
 		udf_delete_aext(table, goal_epos);
 	brelse(goal_epos.bh);

 	udf_add_free_space(sb, partition, -1);

 	mutex_unlock(&sbi->s_alloc_mutex);
 	*err = 0;
 	return newblock;
 }

 void udf_free_blocks(struct super_block *sb, struct inode *inode,
 		     struct kernel_lb_addr *bloc, uint32_t offset,
 		     uint32_t count)
 {
 	uint16_t partition = bloc->partitionReferenceNum;
 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
 	uint32_t blk;

 	if (check_add_overflow(bloc->logicalBlockNum, offset, &blk) ||
 	    check_add_overflow(blk, count, &blk) ||
 	    bloc->logicalBlockNum + count > map->s_partition_len) {
 		udf_debug("Invalid request to free blocks: (%d, %u), off %u, "
 			  "len %u, partition len %u\n",
 			  partition, bloc->logicalBlockNum, offset, count,
 			  map->s_partition_len);
 		return;
 	}

 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
 		udf_bitmap_free_blocks(sb, map->s_uspace.s_bitmap,
 				       bloc, offset, count);
 	} else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE) {
 		udf_table_free_blocks(sb, map->s_uspace.s_table,
 				      bloc, offset, count);
 	}

 	if (inode) {
 		inode_sub_bytes(inode,
 				((sector_t)count) << sb->s_blocksize_bits);
 	}
 }

 inline int udf_prealloc_blocks(struct super_block *sb,
 			       struct inode *inode,
 			       uint16_t partition, uint32_t first_block,
 			       uint32_t block_count)
 {
 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
 	int allocated;

 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
 		allocated = udf_bitmap_prealloc_blocks(sb,
 						       map->s_uspace.s_bitmap,
 						       partition, first_block,
 						       block_count);
 	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
 		allocated = udf_table_prealloc_blocks(sb,
 						      map->s_uspace.s_table,
 						      partition, first_block,
 						      block_count);
 	else
 		return 0;

 	if (inode && allocated > 0)
 		inode_add_bytes(inode, allocated << sb->s_blocksize_bits);
 	return allocated;
 }

 inline udf_pblk_t udf_new_block(struct super_block *sb,
 			 struct inode *inode,
 			 uint16_t partition, uint32_t goal, int *err)
 {
 	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
 	udf_pblk_t block;

 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
 		block = udf_bitmap_new_block(sb,
 					     map->s_uspace.s_bitmap,
 					     partition, goal, err);
 	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
 		block = udf_table_new_block(sb,
 					    map->s_uspace.s_table,
 					    partition, goal, err);
 	else {
 		*err = -EIO;
 		return 0;
 	}
 	if (inode && block)
 		inode_add_bytes(inode, sb->s_blocksize);
 	return block;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* balloc.c
	*
	* PURPOSE
	* Block allocation handling routines for the OSTA-UDF(tm) filesystem.
	*
	* COPYRIGHT
	* (C) 1999-2001 Ben Fennema
	* (C) 1999 Stelias Computing Inc
	*
	* HISTORY
	*
	* 02/24/99 blf Created.
	*
	*/

	#include "udfdecl.h"

	#include <linux/bitops.h>
	#include <linux/overflow.h>

	#include "udf_i.h"
	#include "udf_sb.h"

	#define udf_clear_bit __test_and_clear_bit_le
	#define udf_set_bit __test_and_set_bit_le
	#define udf_test_bit test_bit_le
	#define udf_find_next_one_bit find_next_bit_le

	static int read_block_bitmap(struct super_block *sb,
	struct udf_bitmap *bitmap, unsigned int block,
	unsigned long bitmap_nr)
	{
	struct buffer_head *bh = NULL;
	int i;
	int max_bits, off, count;
	struct kernel_lb_addr loc;

	loc.logicalBlockNum = bitmap->s_extPosition;
	loc.partitionReferenceNum = UDF_SB(sb)->s_partition;

	bh = sb_bread(sb, udf_get_lb_pblock(sb, &loc, block));
	bitmap->s_block_bitmap[bitmap_nr] = bh;
	if (!bh)
	return -EIO;

	/* Check consistency of Space Bitmap buffer. */
	max_bits = sb->s_blocksize * 8;
	if (!bitmap_nr) {
	off = sizeof(struct spaceBitmapDesc) << 3;
	count = min(max_bits - off, bitmap->s_nr_groups);
	} else {
	/*
	* Rough check if bitmap number is too big to have any bitmap
	* blocks reserved.
	*/
	if (bitmap_nr >
	(bitmap->s_nr_groups >> (sb->s_blocksize_bits + 3)) + 2)
	return 0;
	off = 0;
	count = bitmap->s_nr_groups - bitmap_nr * max_bits +
	(sizeof(struct spaceBitmapDesc) << 3);
	count = min(count, max_bits);
	}

	for (i = 0; i < count; i++)
	if (udf_test_bit(i + off, bh->b_data)) {
	bitmap->s_block_bitmap[bitmap_nr] =
	ERR_PTR(-EFSCORRUPTED);
	brelse(bh);
	return -EFSCORRUPTED;
	}
	return 0;
	}

	static int load_block_bitmap(struct super_block *sb,
	struct udf_bitmap *bitmap,
	unsigned int block_group)
	{
	int retval = 0;
	int nr_groups = bitmap->s_nr_groups;

	if (block_group >= nr_groups) {
	udf_debug("block_group (%u) > nr_groups (%d)\n",
	block_group, nr_groups);
	}

	if (bitmap->s_block_bitmap[block_group]) {
	/*
	* The bitmap failed verification in the past. No point in
	* trying again.
	*/
	if (IS_ERR(bitmap->s_block_bitmap[block_group]))
	return PTR_ERR(bitmap->s_block_bitmap[block_group]);
	return block_group;
	}

	retval = read_block_bitmap(sb, bitmap, block_group, block_group);
	if (retval < 0)
	return retval;

	return block_group;
	}

	static void udf_add_free_space(struct super_block *sb, u16 partition, u32 cnt)
	{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct logicalVolIntegrityDesc *lvid;

	if (!sbi->s_lvid_bh)
	return;

	lvid = (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
	le32_add_cpu(&lvid->freeSpaceTable[partition], cnt);
	udf_updated_lvid(sb);
	}

	static void udf_bitmap_free_blocks(struct super_block *sb,
	struct udf_bitmap *bitmap,
	struct kernel_lb_addr *bloc,
	uint32_t offset,
	uint32_t count)
	{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct buffer_head *bh = NULL;
	unsigned long block;
	unsigned long block_group;
	unsigned long bit;
	unsigned long i;
	int bitmap_nr;
	unsigned long overflow;

	mutex_lock(&sbi->s_alloc_mutex);
	/* We make sure this cannot overflow when mounting the filesystem */
	block = bloc->logicalBlockNum + offset +
	(sizeof(struct spaceBitmapDesc) << 3);
	do {
	overflow = 0;
	block_group = block >> (sb->s_blocksize_bits + 3);
	bit = block % (sb->s_blocksize << 3);

	/*
	* Check to see if we are freeing blocks across a group boundary.
	*/
	if (bit + count > (sb->s_blocksize << 3)) {
	overflow = bit + count - (sb->s_blocksize << 3);
	count -= overflow;
	}
	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
	if (bitmap_nr < 0)
	goto error_return;

	bh = bitmap->s_block_bitmap[bitmap_nr];
	for (i = 0; i < count; i++) {
	if (udf_set_bit(bit + i, bh->b_data)) {
	udf_debug("bit %lu already set\n", bit + i);
	udf_debug("byte=%2x\n",
	((__u8 *)bh->b_data)[(bit + i) >> 3]);
	}
	}
	udf_add_free_space(sb, sbi->s_partition, count);
	mark_buffer_dirty(bh);
	if (overflow) {
	block += count;
	count = overflow;
	}
	} while (overflow);

	error_return:
	mutex_unlock(&sbi->s_alloc_mutex);
	}

	static int udf_bitmap_prealloc_blocks(struct super_block *sb,
	struct udf_bitmap *bitmap,
	uint16_t partition, uint32_t first_block,
	uint32_t block_count)
	{
	struct udf_sb_info *sbi = UDF_SB(sb);
	int alloc_count = 0;
	int bit, block, block_group;
	int bitmap_nr;
	struct buffer_head *bh;
	__u32 part_len;

	mutex_lock(&sbi->s_alloc_mutex);
	part_len = sbi->s_partmaps[partition].s_partition_len;
	if (first_block >= part_len)
	goto out;

	if (first_block + block_count > part_len)
	block_count = part_len - first_block;

	do {
	block = first_block + (sizeof(struct spaceBitmapDesc) << 3);
	block_group = block >> (sb->s_blocksize_bits + 3);

	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
	if (bitmap_nr < 0)
	goto out;
	bh = bitmap->s_block_bitmap[bitmap_nr];

	bit = block % (sb->s_blocksize << 3);

	while (bit < (sb->s_blocksize << 3) && block_count > 0) {
	if (!udf_clear_bit(bit, bh->b_data))
	goto out;
	block_count--;
	alloc_count++;
	bit++;
	block++;
	}
	mark_buffer_dirty(bh);
	} while (block_count > 0);

	out:
	udf_add_free_space(sb, partition, -alloc_count);
	mutex_unlock(&sbi->s_alloc_mutex);
	return alloc_count;
	}

	static udf_pblk_t udf_bitmap_new_block(struct super_block *sb,
	struct udf_bitmap *bitmap, uint16_t partition,
	uint32_t goal, int *err)
	{
	struct udf_sb_info *sbi = UDF_SB(sb);
	int newbit, bit = 0;
	udf_pblk_t block;
	int block_group, group_start;
	int end_goal, nr_groups, bitmap_nr, i;
	struct buffer_head *bh = NULL;
	char *ptr;
	udf_pblk_t newblock = 0;

	*err = -ENOSPC;
	mutex_lock(&sbi->s_alloc_mutex);

	repeat:
	if (goal >= sbi->s_partmaps[partition].s_partition_len)
	goal = 0;

	nr_groups = bitmap->s_nr_groups;
	block = goal + (sizeof(struct spaceBitmapDesc) << 3);
	block_group = block >> (sb->s_blocksize_bits + 3);
	group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
	if (bitmap_nr < 0)
	goto error_return;
	bh = bitmap->s_block_bitmap[bitmap_nr];
	ptr = memscan((char *)bh->b_data + group_start, 0xFF,
	sb->s_blocksize - group_start);

	if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
	bit = block % (sb->s_blocksize << 3);
	if (udf_test_bit(bit, bh->b_data))
	goto got_block;

	end_goal = (bit + 63) & ~63;
	bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);
	if (bit < end_goal)
	goto got_block;

	ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF,
	sb->s_blocksize - ((bit + 7) >> 3));
	newbit = (ptr - ((char *)bh->b_data)) << 3;
	if (newbit < sb->s_blocksize << 3) {
	bit = newbit;
	goto search_back;
	}

	newbit = udf_find_next_one_bit(bh->b_data,
	sb->s_blocksize << 3, bit);
	if (newbit < sb->s_blocksize << 3) {
	bit = newbit;
	goto got_block;
	}
	}

	for (i = 0; i < (nr_groups * 2); i++) {
	block_group++;
	if (block_group >= nr_groups)
	block_group = 0;
	group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

	bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
	if (bitmap_nr < 0)
	goto error_return;
	bh = bitmap->s_block_bitmap[bitmap_nr];
	if (i < nr_groups) {
	ptr = memscan((char *)bh->b_data + group_start, 0xFF,
	sb->s_blocksize - group_start);
	if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize) {
	bit = (ptr - ((char *)bh->b_data)) << 3;
	break;
	}
	} else {
	bit = udf_find_next_one_bit(bh->b_data,
	sb->s_blocksize << 3,
	group_start << 3);
	if (bit < sb->s_blocksize << 3)
	break;
	}
	}
	if (i >= (nr_groups * 2)) {
	mutex_unlock(&sbi->s_alloc_mutex);
	return newblock;
	}
	if (bit < sb->s_blocksize << 3)
	goto search_back;
	else
	bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3,
	group_start << 3);
	if (bit >= sb->s_blocksize << 3) {
	mutex_unlock(&sbi->s_alloc_mutex);
	return 0;
	}

	search_back:
	i = 0;
	while (i < 7 && bit > (group_start << 3) &&
	udf_test_bit(bit - 1, bh->b_data)) {
	++i;
	--bit;
	}

	got_block:
	newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -
	(sizeof(struct spaceBitmapDesc) << 3);

	if (newblock >= sbi->s_partmaps[partition].s_partition_len) {
	/*
	* Ran off the end of the bitmap, and bits following are
	* non-compliant (not all zero)
	*/
	udf_err(sb, "bitmap for partition %d corrupted (block %u marked"
	" as free, partition length is %u)\n", partition,
	newblock, sbi->s_partmaps[partition].s_partition_len);
	goto error_return;
	}

	if (!udf_clear_bit(bit, bh->b_data)) {
	udf_debug("bit already cleared for block %d\n", bit);
	goto repeat;
	}

	mark_buffer_dirty(bh);

	udf_add_free_space(sb, partition, -1);
	mutex_unlock(&sbi->s_alloc_mutex);
	*err = 0;
	return newblock;

	error_return:
	*err = -EIO;
	mutex_unlock(&sbi->s_alloc_mutex);
	return 0;
	}

	static void udf_table_free_blocks(struct super_block *sb,
	struct inode *table,
	struct kernel_lb_addr *bloc,
	uint32_t offset,
	uint32_t count)
	{
	struct udf_sb_info *sbi = UDF_SB(sb);
	uint32_t start, end;
	uint32_t elen;
	struct kernel_lb_addr eloc;
	struct extent_position oepos, epos;
	int8_t etype;
	struct udf_inode_info *iinfo;

	mutex_lock(&sbi->s_alloc_mutex);
	iinfo = UDF_I(table);
	udf_add_free_space(sb, sbi->s_partition, count);

	start = bloc->logicalBlockNum + offset;
	end = bloc->logicalBlockNum + offset + count - 1;

	epos.offset = oepos.offset = sizeof(struct unallocSpaceEntry);
	elen = 0;
	epos.block = oepos.block = iinfo->i_location;
	epos.bh = oepos.bh = NULL;

	while (count &&
	(etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
	if (((eloc.logicalBlockNum +
	(elen >> sb->s_blocksize_bits)) == start)) {
	if ((0x3FFFFFFF - elen) <
	(count << sb->s_blocksize_bits)) {
	uint32_t tmp = ((0x3FFFFFFF - elen) >>
	sb->s_blocksize_bits);
	count -= tmp;
	start += tmp;
	elen = (etype << 30) \|
	(0x40000000 - sb->s_blocksize);
	} else {
	elen = (etype << 30) \|
	(elen +
	(count << sb->s_blocksize_bits));
	start += count;
	count = 0;
	}
	udf_write_aext(table, &oepos, &eloc, elen, 1);
	} else if (eloc.logicalBlockNum == (end + 1)) {
	if ((0x3FFFFFFF - elen) <
	(count << sb->s_blocksize_bits)) {
	uint32_t tmp = ((0x3FFFFFFF - elen) >>
	sb->s_blocksize_bits);
	count -= tmp;
	end -= tmp;
	eloc.logicalBlockNum -= tmp;
	elen = (etype << 30) \|
	(0x40000000 - sb->s_blocksize);
	} else {
	eloc.logicalBlockNum = start;
	elen = (etype << 30) \|
	(elen +
	(count << sb->s_blocksize_bits));
	end -= count;
	count = 0;
	}
	udf_write_aext(table, &oepos, &eloc, elen, 1);
	}

	if (epos.bh != oepos.bh) {
	oepos.block = epos.block;
	brelse(oepos.bh);
	get_bh(epos.bh);
	oepos.bh = epos.bh;
	oepos.offset = 0;
	} else {
	oepos.offset = epos.offset;
	}
	}

	if (count) {
	/*
	* NOTE: we CANNOT use udf_add_aext here, as it can try to
	* allocate a new block, and since we hold the super block
	* lock already very bad things would happen :)
	*
	* We copy the behavior of udf_add_aext, but instead of
	* trying to allocate a new block close to the existing one,
	* we just steal a block from the extent we are trying to add.
	*
	* It would be nice if the blocks were close together, but it
	* isn't required.
	*/

	int adsize;

	eloc.logicalBlockNum = start;
	elen = EXT_RECORDED_ALLOCATED \|
	(count << sb->s_blocksize_bits);

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
	adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
	adsize = sizeof(struct long_ad);
	else {
	brelse(oepos.bh);
	brelse(epos.bh);
	goto error_return;
	}

	if (epos.offset + (2 * adsize) > sb->s_blocksize) {
	/* Steal a block from the extent being free'd */
	udf_setup_indirect_aext(table, eloc.logicalBlockNum,
	&epos);

	eloc.logicalBlockNum++;
	elen -= sb->s_blocksize;
	}

	/* It's possible that stealing the block emptied the extent */
	if (elen)
	__udf_add_aext(table, &epos, &eloc, elen, 1);
	}

	brelse(epos.bh);
	brelse(oepos.bh);

	error_return:
	mutex_unlock(&sbi->s_alloc_mutex);
	return;
	}

	static int udf_table_prealloc_blocks(struct super_block *sb,
	struct inode *table, uint16_t partition,
	uint32_t first_block, uint32_t block_count)
	{
	struct udf_sb_info *sbi = UDF_SB(sb);
	int alloc_count = 0;
	uint32_t elen, adsize;
	struct kernel_lb_addr eloc;
	struct extent_position epos;
	int8_t etype = -1;
	struct udf_inode_info *iinfo;

	if (first_block >= sbi->s_partmaps[partition].s_partition_len)
	return 0;

	iinfo = UDF_I(table);
	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
	adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
	adsize = sizeof(struct long_ad);
	else
	return 0;

	mutex_lock(&sbi->s_alloc_mutex);
	epos.offset = sizeof(struct unallocSpaceEntry);
	epos.block = iinfo->i_location;
	epos.bh = NULL;
	eloc.logicalBlockNum = 0xFFFFFFFF;

	while (first_block != eloc.logicalBlockNum &&
	(etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
	udf_debug("eloc=%u, elen=%u, first_block=%u\n",
	eloc.logicalBlockNum, elen, first_block);
	; /* empty loop body */
	}

	if (first_block == eloc.logicalBlockNum) {
	epos.offset -= adsize;

	alloc_count = (elen >> sb->s_blocksize_bits);
	if (alloc_count > block_count) {
	alloc_count = block_count;
	eloc.logicalBlockNum += alloc_count;
	elen -= (alloc_count << sb->s_blocksize_bits);
	udf_write_aext(table, &epos, &eloc,
	(etype << 30) \| elen, 1);
	} else
	udf_delete_aext(table, epos);
	} else {
	alloc_count = 0;
	}

	brelse(epos.bh);

	if (alloc_count)
	udf_add_free_space(sb, partition, -alloc_count);
	mutex_unlock(&sbi->s_alloc_mutex);
	return alloc_count;
	}

	static udf_pblk_t udf_table_new_block(struct super_block *sb,
	struct inode *table, uint16_t partition,
	uint32_t goal, int *err)
	{
	struct udf_sb_info *sbi = UDF_SB(sb);
	uint32_t spread = 0xFFFFFFFF, nspread = 0xFFFFFFFF;
	udf_pblk_t newblock = 0;
	uint32_t adsize;
	uint32_t elen, goal_elen = 0;
	struct kernel_lb_addr eloc, goal_eloc;
	struct extent_position epos, goal_epos;
	int8_t etype;
	struct udf_inode_info *iinfo = UDF_I(table);

	*err = -ENOSPC;

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
	adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
	adsize = sizeof(struct long_ad);
	else
	return newblock;

	mutex_lock(&sbi->s_alloc_mutex);
	if (goal >= sbi->s_partmaps[partition].s_partition_len)
	goal = 0;

	/* We search for the closest matching block to goal. If we find
	a exact hit, we stop. Otherwise we keep going till we run out
	of extents. We store the buffer_head, bloc, and extoffset
	of the current closest match and use that when we are done.
	*/
	epos.offset = sizeof(struct unallocSpaceEntry);
	epos.block = iinfo->i_location;
	epos.bh = goal_epos.bh = NULL;

	while (spread &&
	(etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1) {
	if (goal >= eloc.logicalBlockNum) {
	if (goal < eloc.logicalBlockNum +
	(elen >> sb->s_blocksize_bits))
	nspread = 0;
	else
	nspread = goal - eloc.logicalBlockNum -
	(elen >> sb->s_blocksize_bits);
	} else {
	nspread = eloc.logicalBlockNum - goal;
	}

	if (nspread < spread) {
	spread = nspread;
	if (goal_epos.bh != epos.bh) {
	brelse(goal_epos.bh);
	goal_epos.bh = epos.bh;
	get_bh(goal_epos.bh);
	}
	goal_epos.block = epos.block;
	goal_epos.offset = epos.offset - adsize;
	goal_eloc = eloc;
	goal_elen = (etype << 30) \| elen;
	}
	}

	brelse(epos.bh);

	if (spread == 0xFFFFFFFF) {
	brelse(goal_epos.bh);
	mutex_unlock(&sbi->s_alloc_mutex);
	return 0;
	}

	/* Only allocate blocks from the beginning of the extent.
	That way, we only delete (empty) extents, never have to insert an
	extent because of splitting */
	/* This works, but very poorly.... */

	newblock = goal_eloc.logicalBlockNum;
	goal_eloc.logicalBlockNum++;
	goal_elen -= sb->s_blocksize;

	if (goal_elen)
	udf_write_aext(table, &goal_epos, &goal_eloc, goal_elen, 1);
	else
	udf_delete_aext(table, goal_epos);
	brelse(goal_epos.bh);

	udf_add_free_space(sb, partition, -1);

	mutex_unlock(&sbi->s_alloc_mutex);
	*err = 0;
	return newblock;
	}

	void udf_free_blocks(struct super_block sb, struct inode inode,
	struct kernel_lb_addr *bloc, uint32_t offset,
	uint32_t count)
	{
	uint16_t partition = bloc->partitionReferenceNum;
	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
	uint32_t blk;

	if (check_add_overflow(bloc->logicalBlockNum, offset, &blk) \|\|
	check_add_overflow(blk, count, &blk) \|\|
	bloc->logicalBlockNum + count > map->s_partition_len) {
	udf_debug("Invalid request to free blocks: (%d, %u), off %u, "
	"len %u, partition len %u\n",
	partition, bloc->logicalBlockNum, offset, count,
	map->s_partition_len);
	return;
	}

	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
	udf_bitmap_free_blocks(sb, map->s_uspace.s_bitmap,
	bloc, offset, count);
	} else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE) {
	udf_table_free_blocks(sb, map->s_uspace.s_table,
	bloc, offset, count);
	}

	if (inode) {
	inode_sub_bytes(inode,
	((sector_t)count) << sb->s_blocksize_bits);
	}
	}

	inline int udf_prealloc_blocks(struct super_block *sb,
	struct inode *inode,
	uint16_t partition, uint32_t first_block,
	uint32_t block_count)
	{
	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
	int allocated;

	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
	allocated = udf_bitmap_prealloc_blocks(sb,
	map->s_uspace.s_bitmap,
	partition, first_block,
	block_count);
	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
	allocated = udf_table_prealloc_blocks(sb,
	map->s_uspace.s_table,
	partition, first_block,
	block_count);
	else
	return 0;

	if (inode && allocated > 0)
	inode_add_bytes(inode, allocated << sb->s_blocksize_bits);
	return allocated;
	}

	inline udf_pblk_t udf_new_block(struct super_block *sb,
	struct inode *inode,
	uint16_t partition, uint32_t goal, int *err)
	{
	struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
	udf_pblk_t block;

	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
	block = udf_bitmap_new_block(sb,
	map->s_uspace.s_bitmap,
	partition, goal, err);
	else if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
	block = udf_table_new_block(sb,
	map->s_uspace.s_table,
	partition, goal, err);
	else {
	*err = -EIO;
	return 0;
	}
	if (inode && block)
	inode_add_bytes(inode, sb->s_blocksize);
	return block;
	}