Messages in this thread | | | Date | Thu, 31 Jan 2008 11:51:17 -0500 | Subject | Re: How does ext2 implement sparse files? | From | (Lennart Sorensen) |
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On Thu, Jan 31, 2008 at 04:28:23PM +0100, Lars Noschinski wrote: > For an university project, we had to write a toy filesystem (ext2-like), > for which I would like to implement sparse file support. For this, I > digged through the ext2 source code; but I could not find the point, > where ext2 detects holes. > > As far as I can see from fs/buffer.c, an hole is a buffer_head which is > not mapped, but uptodate. But I cannot find a relevant source line, > where ext2 makes usage of this information. > > Any hints would be greatly appreciated,
While I don't actually know, I always thought it was up to the application to create files with holes by seeking over the holes before writing data. That seems like the simplest way to me.
-- Len Sorensen
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