Re: 2.6.21-git10/11: files getting truncated on xfs? or maybe an nlink problem?

Jeremy Fitzhardinge
2007-05-12T14:56:27Z

David Chinner wrote:
> What I don't understand is that on unmount dirty xfs inodes get
> written out. Clearly this is not happening - either there's a hole
> in the writeback logic (unlikely - it was unchanged) or we've missed
> some case where we need to update the filesize and mark the inode
> dirty.
>
> Hmmmm - if the write was just a short append to the file, then the
> block that was written to should already be mapped. Then we'll just
> look up the extent by doing a BMAPI_READ lookup, set the type to
> IOMAP_READ and add the block to ioend we are building.
>

Well, that result I mailed you showed that the difference was just over
16k, and that there was a 32 block difference in the final extent
length. Does that fit with this theory?

> The type IOMAP_READ determines the I/O completion behaviour - in this case
> it is xfs_end_bio_read(), which fails to update the file size....
>
> Bingo.
>
> A patch for you to try, Jeremy. I've just started a test run on it...
>

Thanks, I'll give it a spin. Have you reproduced the bug yourself?

J