quota: manage reserved space when quota is not active [v2]

Since we implemented generic reserved space management interface,
then it is possible to account reserved space even when quota
is not active (similar to i_blocks/i_bytes).

Without this patch following testcase result in massive comlain from
WARN_ON in dquot_claim_space()

TEST_CASE:
mount /dev/sdb /mnt -oquota
dd if=/dev/zero of=/mnt/test bs=1M count=1
quotaon /mnt
# fs_reserved_spave == 1Mb
# quota_reserved_space == 0, because quota was disabled
dd if=/dev/zero of=/mnt/test seek=1 bs=1M count=1
# fs_reserved_spave == 2Mb
# quota_reserved_space == 1Mb
sync  # ->dquot_claim_space() -> WARN_ON

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
 fs/quota/dquot.c         |   10 ++++++----
 include/linux/quotaops.h |   11 +++++++++--
 2 files changed, 15 insertions(+), 6 deletions(-)

On Thu 17-12-09 18:25:55, Dmitry Monakhov wrote:
> Since we implemented generic reserved space management interface,
> then it is possible to account reserved space even when quota
> is not active (similar to i_blocks/i_bytes).
> 
> Without this patch following testcase result in massive comlain from
> WARN_ON in dquot_claim_space()
> 
> TEST_CASE:
> mount /dev/sdb /mnt -oquota
> dd if=/dev/zero of=/mnt/test bs=1M count=1
> quotaon /mnt
> # fs_reserved_spave == 1Mb
> # quota_reserved_space == 0, because quota was disabled
> dd if=/dev/zero of=/mnt/test seek=1 bs=1M count=1
> # fs_reserved_spave == 2Mb
> # quota_reserved_space == 1Mb
> sync  # ->dquot_claim_space() -> WARN_ON
  Thanks. Folded into "quota: decouple fs reserved space from quota
reservation"

									Honza

> 
> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
> ---
>  fs/quota/dquot.c         |   10 ++++++----
>  include/linux/quotaops.h |   11 +++++++++--
>  2 files changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index dea86ab..a532d44 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -1351,28 +1351,30 @@ static qsize_t *inode_reserved_space(struct inode * inode)
>  	return inode->i_sb->dq_op->get_reserved_space(inode);
>  }
>  
> -static void inode_add_rsv_space(struct inode *inode, qsize_t number)
> +void inode_add_rsv_space(struct inode *inode, qsize_t number)
>  {
>  	spin_lock(&inode->i_lock);
>  	*inode_reserved_space(inode) += number;
>  	spin_unlock(&inode->i_lock);
>  }
> +EXPORT_SYMBOL(inode_add_rsv_space);
>  
> -
> -static void inode_claim_rsv_space(struct inode *inode, qsize_t number)
> +void inode_claim_rsv_space(struct inode *inode, qsize_t number)
>  {
>  	spin_lock(&inode->i_lock);
>  	*inode_reserved_space(inode) -= number;
>  	__inode_add_bytes(inode, number);
>  	spin_unlock(&inode->i_lock);
>  }
> +EXPORT_SYMBOL(inode_claim_rsv_space);
>  
> -static void inode_sub_rsv_space(struct inode *inode, qsize_t number)
> +void inode_sub_rsv_space(struct inode *inode, qsize_t number)
>  {
>  	spin_lock(&inode->i_lock);
>  	*inode_reserved_space(inode) -= number;
>  	spin_unlock(&inode->i_lock);
>  }
> +EXPORT_SYMBOL(inode_sub_rsv_space);
>  
>  static qsize_t inode_get_rsv_space(struct inode *inode)
>  {
> diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
> index 3ebb231..a529d86 100644
> --- a/include/linux/quotaops.h
> +++ b/include/linux/quotaops.h
> @@ -26,6 +26,10 @@ static inline void writeout_quota_sb(struct super_block *sb, int type)
>  		sb->s_qcop->quota_sync(sb, type);
>  }
>  
> +void inode_add_rsv_space(struct inode *inode, qsize_t number);
> +void inode_claim_rsv_space(struct inode *inode, qsize_t number);
> +void inode_sub_rsv_space(struct inode *inode, qsize_t number);
> +
>  int dquot_initialize(struct inode *inode, int type);
>  int dquot_drop(struct inode *inode);
>  struct dquot *dqget(struct super_block *sb, unsigned int id, int type);
> @@ -42,7 +46,6 @@ int dquot_alloc_inode(const struct inode *inode, qsize_t number);
>  int dquot_reserve_space(struct inode *inode, qsize_t number, int prealloc);
>  int dquot_claim_space(struct inode *inode, qsize_t number);
>  void dquot_release_reserved_space(struct inode *inode, qsize_t number);
> -qsize_t dquot_get_reserved_space(struct inode *inode);
>  
>  int dquot_free_space(struct inode *inode, qsize_t number);
>  int dquot_free_inode(const struct inode *inode, qsize_t number);
> @@ -199,6 +202,8 @@ static inline int vfs_dq_reserve_space(struct inode *inode, qsize_t nr)
>  		if (inode->i_sb->dq_op->reserve_space(inode, nr, 0) == NO_QUOTA)
>  			return 1;
>  	}
> +	else
> +		inode_add_rsv_space(inode, nr);
>  	return 0;
>  }
>  
> @@ -221,7 +226,7 @@ static inline int vfs_dq_claim_space(struct inode *inode, qsize_t nr)
>  		if (inode->i_sb->dq_op->claim_space(inode, nr) == NO_QUOTA)
>  			return 1;
>  	} else
> -		inode_add_bytes(inode, nr);
> +		inode_claim_rsv_space(inode, nr);
>  
>  	mark_inode_dirty(inode);
>  	return 0;
> @@ -235,6 +240,8 @@ void vfs_dq_release_reservation_space(struct inode *inode, qsize_t nr)
>  {
>  	if (sb_any_quota_active(inode->i_sb))
>  		inode->i_sb->dq_op->release_rsv(inode, nr);
> +	else
> +		inode_sub_rsv_space(inode, nr);
>  }
>  
>  static inline void vfs_dq_free_space_nodirty(struct inode *inode, qsize_t nr)
> -- 
> 1.6.0.4
>