Re: [patch] make tmpfs_statfs more user friendly

[Christoph Rohland <cr@sap.com>]

Hi Andreas,

On Mon, 5 Feb 2001, Andreas Dilger wrote:
>> diff -uNr 2.4.1-tmpfs/mm/shmem.c 2.4.1-tmpfs-fstat/mm/shmem.c
>> --- 2.4.1-tmpfs/mm/shmem.c	Sun Feb  4 16:08:57 2001
>> +++ 2.4.1-tmpfs-fstat/mm/shmem.c	Sun Feb  4 16:09:50 2001
>> @@ -696,13 +696,20 @@
>>  	buf->f_type = TMPFS_MAGIC;
>>  	buf->f_bsize = PAGE_CACHE_SIZE;
>>  	spin_lock (&sb->u.shmem_sb.stat_lock);
>> -	if (sb->u.shmem_sb.max_blocks != ULONG_MAX || 
>> -	    sb->u.shmem_sb.max_inodes != ULONG_MAX) {
>> +	if (sb->u.shmem_sb.max_blocks == ULONG_MAX) {
>> +		/*
>> +		 * This is only a guestimate and not honoured.
>> +		 * We need it to make some programs happy which like to
>> +		 * test the free space of a file system.
>> +		 */
>> +		buf->f_bavail = buf->f_bfree = nr_free_pages() + nr_swap_pages + atomic_read(&buffermem_pages);
> 
> Should f_bavail be reduced by freepages.min or freepages.low?

Is it still used? If yes, good idea.

>> + buf->f_blocks = buf->f_bfree + ULONG_MAX - sb->u.shmem_sb.free_blocks;
> 
> It's not really clear what you are trying to calculate here... 

(ULONG_MAX - sb->u.shmem_sb.free_blocks) is the number of occupied
blocks by this instance. So the size of the instance should be clearly
buf->f_bfree + ULONG_MAX - sb->u.shmem_sb.free_blocks

> Since f_blocks is a long, adding ULONG_MAX == subtracting 1.  Maybe
> it should just hold the total amount of VM in the system,
> (i.e. totalram_pages)?

Nope, see above

Greetings
		Christoph

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