Re: Big files in ext2fs (but not i_osync)

Albert D. Cahalan (
Tue, 3 Mar 1998 07:20:00 -0500 (EST)

Itai Nahshon writes:
> Albert D. Cahalan wrote:

>> Less complicated:
>> Because of the block groups, fragments will always contain less
>> than 2**16 blocks. Correct? The 12 direct pointers are enough
>> space for 8 extents if you skip the file offset information.
>> The file offset information can be skipped since a linear search
>> through 8 extents is not too bad.
> Maybe, but it does not allow any form of sparse files!

Sure it does, since you can always revert to traditional ext2
as soon as some broken software tries to make a sparse file.
If extents already exist, the remaining ones get filled in with
one-block references to block 0.

A file with 1 block at a random location is never going to be
faster than a file with 1 block at the beginning, and it will
always be slower on traditional unix filesystems like ext2.
I think sparse files are a hack related to a.out binary format
and obsolete database libraries.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to