[Ocfs2-devel] [PATCH 1/2] Ocfs2: Add a new code 'OCFS2_INFO_FREEINODE' for o2info ioctl.

[tristan <tristan.ye@oracle.com>]

Joel Becker wrote:
> On Wed, Nov 03, 2010 at 07:02:05PM +0800, Tristan Ye wrote:
>> The new code is dedicated to calculate free inodes number of all inode_allocs,
>> then return the info to userpace in terms of an array.
>>
>> Specially, flag 'OCFS2_INFO_FL_NON_COHERENT', manipulated by '--cluster-coherent'
>> from userspace, is now going to be involved. setting the flag on means no cluster
>> coherency considered, usually, userspace tools choose none-coherency strategy by
>> default for the sake of performace.
>
> 	This looks pretty straightforward.  Note that any non-cached
> allocator is going to lock, regardless of the coherency flag.  Do we
> want to use ocfs2_ilookup() instead?

A bit confused here, did you mean we use 'ocfs2_ilookup' instead of 
'ocfs2_get_system_file_inode' here?

coherency flag refers to a cluster-aware lock, while 
ocfs2_get_system_file_inode will use iget_locked() to get
the inode if it didn't exist in cache, does iget_locked() also refer to 
a cluster-aware lock somehow?


Or you mean using following logic is not fine?

if (!coherency)
ocfs2_inode_lock();
else
ocfs2_read_inode_block();


>
>> +int ocfs2_info_scan_inode_alloc(struct inode *inode_alloc,
>> +				struct ocfs2_info_freeinode *fi, __u32 slot)
>> +{
>> +	int status = 0, unlock = 0;
>> +
>> +	struct buffer_head *bh = NULL;
>> +	struct ocfs2_dinode *dinode_alloc = NULL;
>> +
>> +	mutex_lock(&inode_alloc->i_mutex);
>> +
>> +	if (!(fi->ifi_req.ir_flags & OCFS2_INFO_FL_NON_COHERENT)) {
>
> 	Also, I'm thinking that this would look much better as:
>
> 	if (!ocfs2_info_coherent(&fi->ifi_req)) {
>
> That implies we probably also want ocfs2_info_set_filled(request), etc.
> Good, bad?

Good idea, it does simplify the codes.

>
> Joel
>