[V5,3/5] ext4: quota handling for delayed allocation

在 2009-01-06二的 10:39 +0100，Jan Kara写道：
> On Tue 06-01-09 10:35:29, Jan Kara wrote:
> > On Mon 05-01-09 20:40:55, Mingming Cao wrote:
> > > ext4: quota reservation for delayed allocation
> > > 
> > > Uses quota reservation/claim/release to handle quota properly for delayed
> > > allocation in the three steps: 1) quotas are reserved when data being copied
> > > to cache when block allocation is defered 2) when new blocks are allocated.
> > > reserved quotas are converted to the real allocated quota, 2) over-booked
> > > quotas for metadata blocks are released back.
> > > 
> > > Signed-off-by: Mingming Cao <cmm@us.ibm.com>
> >   The patch looks fine as far as I can tell :). But I'm not to familiar
> > with the code so I won't add my Acked-by...
>   On a second thought:
> 
> > > +unsigned long long ext4_get_reserved_space(struct inode *inode)
> > > +{
> > > +	unsigned long long total;
> > > +
> > > +	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
> > > +	total = EXT4_I(inode)->i_reserved_data_blocks +
> > > +		EXT4_I(inode)->i_reserved_meta_blocks;
> > > +	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
> > > +
> > > +	return total;
> > > +}
>   Shouldn't we return here (total << inode->i_blksize)? Quota expects
> bytes as output...
> 

This is updated ext4 part to return number of bytes reserved as output.

Thanks,
Mingming

On Mon 12-01-09 16:47:09, Mingming Cao wrote:
> 在 2009-01-06二的 10:39 +0100，Jan Kara写道：
> > On Tue 06-01-09 10:35:29, Jan Kara wrote:
> > > On Mon 05-01-09 20:40:55, Mingming Cao wrote:
> > > > ext4: quota reservation for delayed allocation
> > > > 
> > > > Uses quota reservation/claim/release to handle quota properly for delayed
> > > > allocation in the three steps: 1) quotas are reserved when data being copied
> > > > to cache when block allocation is defered 2) when new blocks are allocated.
> > > > reserved quotas are converted to the real allocated quota, 2) over-booked
> > > > quotas for metadata blocks are released back.
> > > > 
> > > > Signed-off-by: Mingming Cao <cmm@us.ibm.com>
> > >   The patch looks fine as far as I can tell :). But I'm not to familiar
> > > with the code so I won't add my Acked-by...
> >   On a second thought:
> > 
> > > > +unsigned long long ext4_get_reserved_space(struct inode *inode)
> > > > +{
> > > > +	unsigned long long total;
> > > > +
> > > > +	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
> > > > +	total = EXT4_I(inode)->i_reserved_data_blocks +
> > > > +		EXT4_I(inode)->i_reserved_meta_blocks;
> > > > +	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
> > > > +
> > > > +	return total;
> > > > +}
> >   Shouldn't we return here (total << inode->i_blksize)? Quota expects
> > bytes as output...
> > 
> 
> This is updated ext4 part to return number of bytes reserved as output.
  OK, it looks fine now.
Acked-by: Jan Kara <jack@suse.cz>

									Honza
> 
> Thanks,
> Mingming

> ext4: quota reservation for delayed allocation
> 
> Uses quota reservation/claim/release to handle quota properly for delayed
> allocation in the three steps: 1) quotas are reserved when data being copied
> to cache when block allocation is defered 2) when new blocks are allocated.
> reserved quotas are converted to the real allocated quota, 2) over-booked
> quotas for metadata blocks are released back.
> 
> 
> Signed-off-by: Mingming Cao <cmm@us.ibm.com>
> ---
>  fs/ext4/ext4.h    |    1 +
>  fs/ext4/inode.c   |   36 +++++++++++++++++++++++++++++++++---
>  fs/ext4/mballoc.c |   44 ++++++++++++++++++++++++++------------------
>  fs/ext4/super.c   |    4 ++++
>  4 files changed, 64 insertions(+), 21 deletions(-)
> 
> Index: linux-2.6.29-rc1/fs/ext4/inode.c
> ===================================================================
> --- linux-2.6.29-rc1.orig/fs/ext4/inode.c	2009-01-10 15:43:05.000000000 -0800
> +++ linux-2.6.29-rc1/fs/ext4/inode.c	2009-01-12 16:31:34.000000000 -0800
> @@ -973,6 +973,17 @@ out:
>  	return err;
>  }
>  
> +qsize_t ext4_get_reserved_space(struct inode *inode)
> +{
> +	unsigned long long total;
> +
> +	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
> +	total = EXT4_I(inode)->i_reserved_data_blocks +
> +		EXT4_I(inode)->i_reserved_meta_blocks;
> +	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
> +
> +	return (qsize_t)total << inode->i_blkbits;
> +}
>  /*
>   * Calculate the number of metadata blocks need to reserve
>   * to allocate @blocks for non extent file based file
> @@ -1034,8 +1045,14 @@ static void ext4_da_update_reserve_space
>  	/* update per-inode reservations */
>  	BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
>  	EXT4_I(inode)->i_reserved_data_blocks -= used;
> -
>  	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
> +
> +	/*
> +	 * free those over-booking quota for metadata blocks
> +	 */
> +
> +	if (mdb_free)
> +		vfs_dq_release_reservation_block(inode, mdb_free);
>  }
>  
>  /*
> @@ -1547,8 +1564,8 @@ static int ext4_journalled_write_end(str
>  static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
>  {
>  	int retries = 0;
> -       struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> -       unsigned long md_needed, mdblocks, total = 0;
> +	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> +	unsigned long md_needed, mdblocks, total = 0;
>  
>  	/*
>  	 * recalculate the amount of metadata blocks to reserve
> @@ -1564,12 +1581,23 @@ repeat:
>  	md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
>  	total = md_needed + nrblocks;
>  
> +	/*
> +	 * Make quota reservation here to prevent quota overflow
> +	 * later. Real quota accounting is done at pages writeout
> +	 * time.
> +	 */
> +	if (vfs_dq_reserve_block(inode, total)) {
> +		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
> +		return -EDQUOT;
> +	}
> +
>  	if (ext4_claim_free_blocks(sbi, total)) {
>  		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
>  		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
>  			yield();
>  			goto repeat;
>  		}
> +		vfs_dq_release_reservation_block(inode, total);
>  		return -ENOSPC;
>  	}
>  	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
> @@ -1623,6 +1651,8 @@ static void ext4_da_release_space(struct
>  	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
>  	EXT4_I(inode)->i_reserved_meta_blocks = mdb;
>  	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
> +
> +	vfs_dq_release_reservation_block(inode, release);
>  }
>  
>  static void ext4_da_page_release_reservation(struct page *page,
> Index: linux-2.6.29-rc1/fs/ext4/super.c
> ===================================================================
> --- linux-2.6.29-rc1.orig/fs/ext4/super.c	2009-01-10 15:43:05.000000000 -0800
> +++ linux-2.6.29-rc1/fs/ext4/super.c	2009-01-12 16:28:44.000000000 -0800
> @@ -945,6 +945,10 @@ static struct dquot_operations ext4_quot
>  	.initialize	= ext4_dquot_initialize,
>  	.drop		= ext4_dquot_drop,
>  	.alloc_space	= dquot_alloc_space,
> +	.reserve_space	= dquot_reserve_space,
> +	.claim_space	= dquot_claim_space,
> +	.release_rsv	= dquot_release_reserved_space,
> +	.get_reserved_space = ext4_get_reserved_space,
>  	.alloc_inode	= dquot_alloc_inode,
>  	.free_space	= dquot_free_space,
>  	.free_inode	= dquot_free_inode,
> Index: linux-2.6.29-rc1/fs/ext4/mballoc.c
> ===================================================================
> --- linux-2.6.29-rc1.orig/fs/ext4/mballoc.c	2009-01-10 15:43:05.000000000 -0800
> +++ linux-2.6.29-rc1/fs/ext4/mballoc.c	2009-01-12 16:28:44.000000000 -0800
> @@ -3086,9 +3086,12 @@ ext4_mb_mark_diskspace_used(struct ext4_
>  	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
>  		/* release all the reserved blocks if non delalloc */
>  		percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks);
> -	else
> +	else {
>  		percpu_counter_sub(&sbi->s_dirtyblocks_counter,
>  						ac->ac_b_ex.fe_len);
> +		/* convert reserved quota blocks to real quota blocks */
> +		vfs_dq_claim_block(ac->ac_inode, ac->ac_b_ex.fe_len);
> +	}
>  
>  	if (sbi->s_log_groups_per_flex) {
>  		ext4_group_t flex_group = ext4_flex_group(sbi,
> @@ -4533,7 +4536,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
>  	struct ext4_sb_info *sbi;
>  	struct super_block *sb;
>  	ext4_fsblk_t block = 0;
> -	unsigned int inquota;
> +	unsigned int inquota = 0;
>  	unsigned int reserv_blks = 0;
>  
>  	sb = ar->inode->i_sb;
> @@ -4551,9 +4554,17 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
>  		   (unsigned long long) ar->pleft,
>  		   (unsigned long long) ar->pright);
>  
> -	if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag) {
> -		/*
> -		 * With delalloc we already reserved the blocks
> +	/*
> +	 * For delayed allocation, we could skip the ENOSPC and
> +	 * EDQUOT check, as blocks and quotas have been already
> +	 * reserved when data being copied into pagecache.
> +	 */
> +	if (EXT4_I(ar->inode)->i_delalloc_reserved_flag)
> +		ar->flags |= EXT4_MB_DELALLOC_RESERVED;
> +	else {
> +		/* Without delayed allocation we need to verify
> +		 * there is enough free blocks to do block allocation
> +		 * and verify allocation doesn't exceed the quota limits.
>  		 */
>  		while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
>  			/* let others to free the space */
> @@ -4565,19 +4576,16 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
>  			return 0;
>  		}
>  		reserv_blks = ar->len;
> +		while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) {
> +			ar->flags |= EXT4_MB_HINT_NOPREALLOC;
> +			ar->len--;
> +		}
> +		inquota = ar->len;
> +		if (ar->len == 0) {
> +			*errp = -EDQUOT;
> +			goto out3;
> +		}
>  	}
> -	while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) {
> -		ar->flags |= EXT4_MB_HINT_NOPREALLOC;
> -		ar->len--;
> -	}
> -	if (ar->len == 0) {
> -		*errp = -EDQUOT;
> -		goto out3;
> -	}
> -	inquota = ar->len;
> -
> -	if (EXT4_I(ar->inode)->i_delalloc_reserved_flag)
> -		ar->flags |= EXT4_MB_DELALLOC_RESERVED;
>  
>  	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
>  	if (!ac) {
> @@ -4643,7 +4651,7 @@ repeat:
>  out2:
>  	kmem_cache_free(ext4_ac_cachep, ac);
>  out1:
> -	if (ar->len < inquota)
> +	if (inquota && ar->len < inquota)
>  		DQUOT_FREE_BLOCK(ar->inode, inquota - ar->len);
>  out3:
>  	if (!ar->len) {
> Index: linux-2.6.29-rc1/fs/ext4/ext4.h
> ===================================================================
> --- linux-2.6.29-rc1.orig/fs/ext4/ext4.h	2009-01-10 15:43:05.000000000 -0800
> +++ linux-2.6.29-rc1/fs/ext4/ext4.h	2009-01-12 16:28:44.000000000 -0800
> @@ -1098,6 +1098,7 @@ extern int ext4_chunk_trans_blocks(struc
>  extern int ext4_block_truncate_page(handle_t *handle,
>  		struct address_space *mapping, loff_t from);
>  extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page);
> +extern qsize_t ext4_get_reserved_space(struct inode *inode);
>  
>  /* ioctl.c */
>  extern long ext4_ioctl(struct file *, unsigned int, unsigned long);