> To simplify metadata tracking for delalloc writes, ext4
> will simply claim metadata blocks at allocation time, without
> first speculatively reserving the worst case and then freeing
> what was not used.
>
> To do this, we need a mechanism to track allocations in
> the quota subsystem, but potentially allow that allocation
> to actually go over quota.
>
> This patch adds a DQUOT_SPACE_NOFAIL flag and function
> variants for this purpose.
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Looks fine. Acked-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
>
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index 8436d9b..c38b137 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -1490,6 +1490,7 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
> char warntype[MAXQUOTAS];
> int warn = flags & DQUOT_SPACE_WARN;
> int reserve = flags & DQUOT_SPACE_RESERVE;
> + int nofail = flags & DQUOT_SPACE_NOFAIL;
>
> /*
> * First test before acquiring mutex - solves deadlocks when we
> @@ -1510,7 +1511,7 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
> continue;
> ret = check_bdq(inode->i_dquot[cnt], number, !warn,
> warntype+cnt);
> - if (ret) {
> + if (ret && !nofail) {
> spin_unlock(&dq_data_lock);
> goto out_flush_warn;
> }
> diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
> index daa106f..8f858ce 100644
> --- a/include/linux/quotaops.h
> +++ b/include/linux/quotaops.h
> @@ -16,6 +16,7 @@ static inline struct quota_info *sb_dqopt(struct super_block *sb)
>
> #define DQUOT_SPACE_WARN 0x1
> #define DQUOT_SPACE_RESERVE 0x2
> +#define DQUOT_SPACE_NOFAIL 0x4
>
> #if defined(CONFIG_QUOTA)
>
> @@ -262,6 +263,12 @@ static inline int dquot_alloc_space_nodirty(struct inode *inode, qsize_t nr)
> return __dquot_alloc_space(inode, nr, DQUOT_SPACE_WARN);
> }
>
> +static inline void dquot_alloc_space_nofail(struct inode *inode, qsize_t nr)
> +{
> + __dquot_alloc_space(inode, nr, DQUOT_SPACE_WARN|DQUOT_SPACE_NOFAIL);
> + mark_inode_dirty(inode);
> +}
> +
> static inline int dquot_alloc_space(struct inode *inode, qsize_t nr)
> {
> int ret;
> @@ -277,6 +284,11 @@ static inline int dquot_alloc_block_nodirty(struct inode *inode, qsize_t nr)
> return dquot_alloc_space_nodirty(inode, nr << inode->i_blkbits);
> }
>
> +static inline void dquot_alloc_block_nofail(struct inode *inode, qsize_t nr)
> +{
> + dquot_alloc_space_nofail(inode, nr << inode->i_blkbits);
> +}
> +
> static inline int dquot_alloc_block(struct inode *inode, qsize_t nr)
> {
> return dquot_alloc_space(inode, nr << inode->i_blkbits);
>
> --
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--
Jan Kara <jack@xxxxxxx>
SuSE CR Labs
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