Re: [PATCH] ext4: Support large files

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Andreas Dilger wrote:
> On Oct 11, 2007  10:41 +0530, Aneesh Kumar K.V wrote:
>> This patch converts ext4_inode i_blocks to represent total
>> blocks occupied by the inode in file system block size.
>> Earlier the variable used to represent this in 512 byte
>> block size. This actually limited the total size of the file.
>>
>> This is enabled only if the incompat feature flag
>> EXT4_FEATURE_INCOMPAT_LARGE_BLOCK is set in super block
>> and the kernel is built with CONFIG_LSF.
> 
> NACK.  This must be an old version of the patch.  The major problem is
> that there is no way to incrementally enable this feature, so as soon
> as some file needs to be larger than 2TB, it means that the i_blocks
> count on EVERY file needs to be updated, or it will be incorrect.
> 
> The updated proposal was to set EXT4_HUGE_FILE_FL on the inodes that
> are using fs-blocksize for i_blocks, and if this flag is not set then
> use 512-byte i_blocks.  This allows the filesystem to be compatible
> unless there really are gigantic files.
> 

So how do we calculate ext4_max_size ? Can we do 

if CONFIG_LSF is set then consider that that i_blocks can be represented 
using file system block size ?

-aneesh