Re: [PATCH 5/8] exofs: dir_inode and directory operations

[Boaz Harrosh <bharrosh@panasas.com>]

On 03/31/2009 11:04 AM, Andrew Morton wrote:
> On Wed, 18 Mar 2009 20:08:49 +0200 Boaz Harrosh <bharrosh@panasas.com> wrote:
> 
>> implementation of directory and inode operations.
>>
>> * A directory is treated as a file, and essentially contains a list
>>   of <file name, inode #> pairs for files that are found in that
>>   directory. The object IDs correspond to the files' inode numbers
>>   and are allocated using a 64bit incrementing global counter.
>> * Each file's control block (AKA on-disk inode) is stored in its
>>   object's attributes. This applies to both regular files and other
>>   types (directories, device files, symlinks, etc.).
>>
>>
>> ...
>>
>> +static inline unsigned long dir_pages(struct inode *inode)
>> +{
>> +	return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
>> +}
> 
> Do we need i_size_read() here?  Probably not if it's always called
> under i_mutex.  Needs checking and commenting please.
> 

Don't know, I'll have a look

>> +static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
>> +{
>> +	unsigned last_byte = inode->i_size;
>> +
>> +	last_byte -= page_nr << PAGE_CACHE_SHIFT;
> 
> hm.  Strange to left-shift an unsigned long and then copy it to a
> smaller type.
> 

wrong type, thanks!

> Are the types here appropriately chosen?
> 
>> +	if (last_byte > PAGE_CACHE_SIZE)
>> +		last_byte = PAGE_CACHE_SIZE;
>> +	return last_byte;
>> +}
>> +
>> +static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
>>
>> ...
>>
> 
> This all looks vaguely familiar :)

Yep ;). Don't forget that all this started with a cp ...

Boaz