Commit d5b8f310 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: bigalloc changes to block bitmap initialization functions 



Add bigalloc support to ext4_init_block_bitmap() and
ext4_free_blocks_after_init().

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent fd034a84

fs/ext4/balloc.c

+90 −41
Original line number Diff line number Diff line
@@ -23,9 +23,6 @@ 


#include <trace/events/ext4.h>



static unsigned int num_base_meta_blocks(struct super_block *sb,

					 ext4_group_t block_group);



/*

 * balloc.c contains the blocks allocation and deallocation routines

 */
@@ -58,37 +55,87 @@ static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block, 
	return 0;

}



static int ext4_group_used_meta_blocks(struct super_block *sb,

/* Return the number of clusters used for file system metadata; this

 * represents the overhead needed by the file system.

 */

unsigned ext4_num_overhead_clusters(struct super_block *sb,

				    ext4_group_t block_group,

				    struct ext4_group_desc *gdp)

{

	ext4_fsblk_t tmp;

	unsigned num_clusters;

	int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;

	ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);

	ext4_fsblk_t itbl_blk;

	struct ext4_sb_info *sbi = EXT4_SB(sb);

	/* block bitmap, inode bitmap, and inode table blocks */

	int used_blocks = sbi->s_itb_per_group + 2;



	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {

		if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),

					block_group))

			used_blocks--;



		if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp),

					block_group))

			used_blocks--;

	/* This is the number of clusters used by the superblock,

	 * block group descriptors, and reserved block group

	 * descriptor blocks */

	num_clusters = ext4_num_base_meta_clusters(sb, block_group);



		tmp = ext4_inode_table(sb, gdp);

		for (; tmp < ext4_inode_table(sb, gdp) +

				sbi->s_itb_per_group; tmp++) {

			if (!ext4_block_in_group(sb, tmp, block_group))

				used_blocks -= 1;

	/*

	 * For the allocation bitmaps and inode table, we first need

	 * to check to see if the block is in the block group.  If it

	 * is, then check to see if the cluster is already accounted

	 * for in the clusters used for the base metadata cluster, or

	 * if we can increment the base metadata cluster to include

	 * that block.  Otherwise, we will have to track the cluster

	 * used for the allocation bitmap or inode table explicitly.

	 * Normally all of these blocks are contiguous, so the special

	 * case handling shouldn't be necessary except for *very*

	 * unusual file system layouts.

	 */

	if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {

		block_cluster = EXT4_B2C(sbi, (start -

					       ext4_block_bitmap(sb, gdp)));

		if (block_cluster < num_clusters)

			block_cluster = -1;

		else if (block_cluster == num_clusters) {

			num_clusters++;

			block_cluster = -1;

		}

	}



	if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {

		inode_cluster = EXT4_B2C(sbi,

					 start - ext4_inode_bitmap(sb, gdp));

		if (inode_cluster < num_clusters)

			inode_cluster = -1;

		else if (inode_cluster == num_clusters) {

			num_clusters++;

			inode_cluster = -1;

		}

	}



	itbl_blk = ext4_inode_table(sb, gdp);

	for (i = 0; i < sbi->s_itb_per_group; i++) {

		if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {

			c = EXT4_B2C(sbi, start - itbl_blk + i);

			if ((c < num_clusters) || (c == inode_cluster) ||

			    (c == block_cluster) || (c == itbl_cluster))

				continue;

			if (c == num_clusters) {

				num_clusters++;

				continue;

			}

			num_clusters++;

			itbl_cluster = c;

		}

	}

	return used_blocks;



	if (block_cluster != -1)

		num_clusters++;

	if (inode_cluster != -1)

		num_clusters++;



	return num_clusters;

}



static unsigned int num_blocks_in_group(struct super_block *sb,

static unsigned int num_clusters_in_group(struct super_block *sb,

					  ext4_group_t block_group)

{

	unsigned int blocks;



	if (block_group == ext4_get_groups_count(sb) - 1) {

		/*

		 * Even though mke2fs always initializes the first and
@@ -96,10 +143,11 @@ static unsigned int num_blocks_in_group(struct super_block *sb, 
		 * we need to make sure we calculate the right free

		 * blocks.

		 */

		return ext4_blocks_count(EXT4_SB(sb)->s_es) -

		blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -

			ext4_group_first_block_no(sb, block_group);

	} else

		return EXT4_BLOCKS_PER_GROUP(sb);

		blocks = EXT4_BLOCKS_PER_GROUP(sb);

	return EXT4_NUM_B2C(EXT4_SB(sb), blocks);

}



/* Initializes an uninitialized block bitmap */
@@ -107,7 +155,7 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, 
			    ext4_group_t block_group,

			    struct ext4_group_desc *gdp)

{

	unsigned int bit, bit_max = num_base_meta_blocks(sb, block_group);

	unsigned int bit, bit_max;

	struct ext4_sb_info *sbi = EXT4_SB(sb);

	ext4_fsblk_t start, tmp;

	int flex_bg = 0;
@@ -126,6 +174,7 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, 
	}

	memset(bh->b_data, 0, sb->s_blocksize);



	bit_max = ext4_num_base_meta_clusters(sb, block_group);

	for (bit = 0; bit < bit_max; bit++)

		ext4_set_bit(bit, bh->b_data);
@@ -137,24 +186,25 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, 
	/* Set bits for block and inode bitmaps, and inode table */

	tmp = ext4_block_bitmap(sb, gdp);

	if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))

		ext4_set_bit(tmp - start, bh->b_data);

		ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);



	tmp = ext4_inode_bitmap(sb, gdp);

	if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))

		ext4_set_bit(tmp - start, bh->b_data);

		ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);



	tmp = ext4_inode_table(sb, gdp);

	for (; tmp < ext4_inode_table(sb, gdp) +

		     sbi->s_itb_per_group; tmp++) {

		if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))

			ext4_set_bit(tmp - start, bh->b_data);

			ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);

	}



	/*

	 * Also if the number of blocks within the group is less than

	 * the blocksize * 8 ( which is the size of bitmap ), set rest

	 * of the block bitmap to 1

	 */

	ext4_mark_bitmap_end(num_blocks_in_group(sb, block_group),

	ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),

			     sb->s_blocksize * 8, bh->b_data);

}
@@ -165,9 +215,8 @@ unsigned ext4_free_blocks_after_init(struct super_block *sb, 
				     ext4_group_t block_group,

				     struct ext4_group_desc *gdp)

{

	return num_blocks_in_group(sb, block_group) -

		num_base_meta_blocks(sb, block_group) -

		ext4_group_used_meta_blocks(sb, block_group, gdp);

	return num_clusters_in_group(sb, block_group) - 

		ext4_num_overhead_clusters(sb, block_group, gdp);

}



/*
@@ -611,14 +660,14 @@ unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 
}



/*

 * This function returns the number of file system metadata blocks at

 * This function returns the number of file system metadata clusters at

 * the beginning of a block group, including the reserved gdt blocks.

 */

static unsigned int num_base_meta_blocks(struct super_block *sb,

unsigned ext4_num_base_meta_clusters(struct super_block *sb,

				     ext4_group_t block_group)

{

	struct ext4_sb_info *sbi = EXT4_SB(sb);

	int num;

	unsigned num;



	/* Check for superblock and gdt backups in this group */

	num = ext4_bg_has_super(sb, block_group);
@@ -633,7 +682,7 @@ static unsigned int num_base_meta_blocks(struct super_block *sb, 
	} else { /* For META_BG_BLOCK_GROUPS */

		num += ext4_bg_num_gdb(sb, block_group);

	}

	return num;

	return EXT4_NUM_B2C(sbi, num);

}

/**

 *	ext4_inode_to_goal_block - return a hint for block allocation

fs/ext4/ext4.h

+13 −0
Original line number Diff line number Diff line
@@ -261,6 +261,14 @@ struct ext4_io_submit { 
#endif

#define EXT4_BLOCK_ALIGN(size, blkbits)		ALIGN((size), (1 << (blkbits)))



/* Translate a block number to a cluster number */

#define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)

/* Translate a cluster number to a block number */

#define EXT4_C2B(sbi, cluster)	((cluster) << (sbi)->s_cluster_bits)

/* Translate # of blks to # of clusters */

#define EXT4_NUM_B2C(sbi, blks)	(((blks) + (sbi)->s_cluster_ratio - 1) >> \

				 (sbi)->s_cluster_bits)



/*

 * Structure of a blocks group descriptor

 */
@@ -1770,6 +1778,11 @@ extern void ext4_init_block_bitmap(struct super_block *sb, 
extern unsigned ext4_free_blocks_after_init(struct super_block *sb,

					    ext4_group_t block_group,

					    struct ext4_group_desc *gdp);

extern unsigned ext4_num_base_meta_clusters(struct super_block *sb,

					    ext4_group_t block_group);

extern unsigned ext4_num_overhead_clusters(struct super_block *sb,

					   ext4_group_t block_group,

					   struct ext4_group_desc *gdp);

ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);



/* dir.c */