[PATCH v2 01/12] xfs: add a helper to figure out the space log reservation per item

[Mark Tinguely]

On 01/10/13 07:47, Jeff Liu wrote:
> Add a helper xfs_calc_buf_res() to calcuate out the space log reservations per item which were got
> involved in a transaction.  It will call the xfs_buf_log_overhead() to figure out the extra space
> for the struct xfs_buf_log_format that gets written into the log for every buffer as well as a little
> bit of extra space because there also needs a log opheader, i.e. struct xlog_op_header.
>
The commit message is too wide.

> Signed-off-by: Jie Liu<jeff.liu at oracle.com>
> ---
>   fs/xfs/xfs_trans.c |   31 +++++++++++++++++++++++++++++++
>   1 file changed, 31 insertions(+)
>
> diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
> index 06ed520..6c601ea 100644
> --- a/fs/xfs/xfs_trans.c
> +++ b/fs/xfs/xfs_trans.c
> @@ -37,14 +37,45 @@
>   #include "xfs_extent_busy.h"
>   #include "xfs_bmap.h"
>   #include "xfs_quota.h"
> +#include "xfs_qm.h"
>   #include "xfs_trans_priv.h"
>   #include "xfs_trans_space.h"
>   #include "xfs_inode_item.h"
> +#include "xfs_log_priv.h"
> +#include "xfs_buf_item.h"
>   #include "xfs_trace.h"
>
>   kmem_zone_t	*xfs_trans_zone;
>   kmem_zone_t	*xfs_log_item_desc_zone;
>
> +/*
> + * A buffer has a format structure overhead in the log in addition
> + * to the data, so we need to take this into account when reserving
> + * space in a transaction for a buffer.  Round the space required up
> + * to a multiple of 128 bytes so that we don't change the historical
> + * reservation that has been used for this overhead.
> + */
> +STATIC uint
> +xfs_buf_log_overhead(void)
> +{
> +	return round_up(sizeof(struct xlog_op_header) +
> +			sizeof(struct xfs_buf_log_format), 128);
> +}

Not used directly except below. inline or fold below?

--Mark.