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Commit 3212a80a authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: convert block group-relative offsets to use clusters 



Certain parts of the ext4 code base, primarily in mballoc.c, use a
block group number and offset from the beginning of the block group.
This offset is invariably used to index into the allocation bitmap, so
change the offset to be denominated in units of clusters.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent d5b8f310

fs/ext4/balloc.c

+4 −2
Original line number Diff line number Diff line
@@ -28,7 +28,8 @@ 
 */



/*

 * Calculate the block group number and offset, given a block number

 * Calculate the block group number and offset into the block/cluster

 * allocation bitmap, given a block number

 */

void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,

		ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
@@ -37,7 +38,8 @@ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, 
	ext4_grpblk_t offset;



	blocknr = blocknr - le32_to_cpu(es->s_first_data_block);

	offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb));

	offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>

		EXT4_SB(sb)->s_cluster_bits;

	if (offsetp)

		*offsetp = offset;

	if (blockgrpp)

fs/ext4/mballoc.h

+2 −1
Original line number Diff line number Diff line
@@ -216,6 +216,7 @@ struct ext4_buddy { 
static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,

					struct ext4_free_extent *fex)

{

	return ext4_group_first_block_no(sb, fex->fe_group) + fex->fe_start;

	return ext4_group_first_block_no(sb, fex->fe_group) +

		(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);

}

#endif