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Commit 12219aea authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o
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ext4: Cleanup the block reservation code path 



The truncate patch should not use the i_allocated_meta_blocks
value. So add seperate functions to be used in the truncate
and alloc path. We also need to release the meta-data block
that we reserved for the blocks that we are truncating.

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 34071da7

fs/ext4/ext4.h

+0 −1
Original line number Diff line number Diff line
@@ -1044,7 +1044,6 @@ extern void ext4_mb_update_group_info(struct ext4_group_info *grp, 




/* inode.c */

void ext4_da_release_space(struct inode *inode, int used, int to_free);

int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,

		struct buffer_head *bh, ext4_fsblk_t blocknr);

struct buffer_head *ext4_getblk(handle_t *, struct inode *,

fs/ext4/inode.c

+67 −41
Original line number Diff line number Diff line
@@ -980,6 +980,67 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode, 
	return err;

}



/*

 * Calculate the number of metadata blocks need to reserve

 * to allocate @blocks for non extent file based file

 */

static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)

{

	int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);

	int ind_blks, dind_blks, tind_blks;



	/* number of new indirect blocks needed */

	ind_blks = (blocks + icap - 1) / icap;



	dind_blks = (ind_blks + icap - 1) / icap;



	tind_blks = 1;



	return ind_blks + dind_blks + tind_blks;

}



/*

 * Calculate the number of metadata blocks need to reserve

 * to allocate given number of blocks

 */

static int ext4_calc_metadata_amount(struct inode *inode, int blocks)

{

	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)

		return ext4_ext_calc_metadata_amount(inode, blocks);



	return ext4_indirect_calc_metadata_amount(inode, blocks);

}



static void ext4_da_update_reserve_space(struct inode *inode, int used)

{

	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

	int total, mdb, mdb_free;



	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);

	/* recalculate the number of metablocks still need to be reserved */

	total = EXT4_I(inode)->i_reserved_data_blocks - used;

	mdb = ext4_calc_metadata_amount(inode, total);



	/* figure out how many metablocks to release */

	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);

	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;



	/* Account for allocated meta_blocks */

	mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;



	/* update fs free blocks counter for truncate case */

	percpu_counter_add(&sbi->s_freeblocks_counter, mdb_free);



	/* update per-inode reservations */

	BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);

	EXT4_I(inode)->i_reserved_data_blocks -= used;



	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);

	EXT4_I(inode)->i_reserved_meta_blocks = mdb;

	EXT4_I(inode)->i_allocated_meta_blocks = 0;

	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

}



/* Maximum number of blocks we map for direct IO at once. */

#define DIO_MAX_BLOCKS 4096

/*
@@ -1097,7 +1158,7 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, 
		 * which were deferred till now

		 */

		if ((retval > 0) && buffer_delay(bh))

			ext4_da_release_space(inode, retval, 0);

			ext4_da_update_reserve_space(inode, retval);

	}



	up_write((&EXT4_I(inode)->i_data_sem));
@@ -1465,36 +1526,6 @@ static int ext4_journalled_write_end(struct file *file, 


	return ret ? ret : copied;

}

/*

 * Calculate the number of metadata blocks need to reserve

 * to allocate @blocks for non extent file based file

 */

static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)

{

	int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);

	int ind_blks, dind_blks, tind_blks;



	/* number of new indirect blocks needed */

	ind_blks = (blocks + icap - 1) / icap;



	dind_blks = (ind_blks + icap - 1) / icap;



	tind_blks = 1;



	return ind_blks + dind_blks + tind_blks;

}



/*

 * Calculate the number of metadata blocks need to reserve

 * to allocate given number of blocks

 */

static int ext4_calc_metadata_amount(struct inode *inode, int blocks)

{

	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)

		return ext4_ext_calc_metadata_amount(inode, blocks);



	return ext4_indirect_calc_metadata_amount(inode, blocks);

}



static int ext4_da_reserve_space(struct inode *inode, int nrblocks)

{
@@ -1518,7 +1549,6 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks) 
		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

		return -ENOSPC;

	}



	/* reduce fs free blocks counter */

	percpu_counter_sub(&sbi->s_freeblocks_counter, total);
@@ -1529,35 +1559,31 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks) 
	return 0;       /* success */

}



void ext4_da_release_space(struct inode *inode, int used, int to_free)

static void ext4_da_release_space(struct inode *inode, int to_free)

{

	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

	int total, mdb, mdb_free, release;



	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);

	/* recalculate the number of metablocks still need to be reserved */

	total = EXT4_I(inode)->i_reserved_data_blocks - used - to_free;

	total = EXT4_I(inode)->i_reserved_data_blocks - to_free;

	mdb = ext4_calc_metadata_amount(inode, total);



	/* figure out how many metablocks to release */

	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);

	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;



	/* Account for allocated meta_blocks */

	mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;



	release = to_free + mdb_free;



	/* update fs free blocks counter for truncate case */

	percpu_counter_add(&sbi->s_freeblocks_counter, release);



	/* update per-inode reservations */

	BUG_ON(used + to_free > EXT4_I(inode)->i_reserved_data_blocks);

	EXT4_I(inode)->i_reserved_data_blocks -= (used + to_free);

	BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);

	EXT4_I(inode)->i_reserved_data_blocks -= to_free;



	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);

	EXT4_I(inode)->i_reserved_meta_blocks = mdb;

	EXT4_I(inode)->i_allocated_meta_blocks = 0;

	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

}
@@ -1579,7 +1605,7 @@ static void ext4_da_page_release_reservation(struct page *page, 
		}

		curr_off = next_off;

	} while ((bh = bh->b_this_page) != head);

	ext4_da_release_space(page->mapping->host, 0, to_release);

	ext4_da_release_space(page->mapping->host, to_release);

}



/*