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

[Mark Tinguely]

On 01/18/13 21:28, Jeff Liu wrote:
> On 01/19/2013 07:03 AM, Mark Tinguely wrote:
>> 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?
> I should be inline.  Maybe it's proper to make xfs_calc_buf_res() inline
> as well?

Looks like these routines just get run at boot time - the existing 
reservations routines that run at boot time are routines too, so you are 
following the existing style. So I don't want to build a bikeshed so I 
am flexible on this point.

There appears seems to be some errors in patch 2....

--Mark.