Re: a question about quota credits ...

> Good day,
> 
> in include/linux/ext3_jbd.h:
> 
> /* Define the number of blocks we need to account to a transaction to
>  * modify one block of data.
>  * 
>  * We may have to touch one inode, one bitmap buffer, up to three
>  * indirection blocks, the group and superblock summaries, and the data
>  * block to complete the transaction.  */
> 
> #define EXT3_SINGLEDATA_TRANS_BLOCKS	8U
> 
> 
> who does take a care about allocation those indirect blocks?
> 
> shouldn't it be like this:
> 
>    inode                 - 1
> +  3 indirect blocks     - 3 * 4 (bitmap + group + sb + block itself)
> +  data block            - 4 (bitmap + group + sb + block itself)
> = 17
  Umm, you are right we may end up using more blocks as far as I can see.
You can reduce your estimate by counting 'sb' just once so you get to
14 blocks but it's still more than 8. I guess we originally assumed that
indirect blocks are allocated in the same group as the data block. That
is mostly the case but not necessarily...

								Honza