Andreas Dilger wrote: > On 2010-07-05, at 13:24, Eric Sandeen wrote: >> [root@host ~]# filefrag -B /mnt/test/file >> /mnt/test/file: 34 extents found >> [root@host ~]# filefrag /mnt/test/file >> /mnt/test/file: 1058 extents found, perfection would be 1 extent >> >> Hum, is it 34 or 1058? :) > > What do the extents look like on disk? Is this just because it is running on a block-mapped file and is skipping a singleton block periodically for indirect blocks, or is there a bug in the way the extents are being reported? Well, I didn't actually look but I'm 98% sure it's just because it's not reporting the interspersed metadata blocks. Sorry, above was on ext3, that wasn't clear, just a stock dd-streamed file. >> Older filefrag counted contiguous metadata as part of a contiguous >> extent... newer filefrag works in fiemap query-only mode by default, >> and just takes what fiemap tells it. The inconsistency is weird >> though, and led to a Red Hat bug that I'm inclined to NOTABUG... but >> do people think this needs to be made any more consistent? >> >> Should we hack ext3_fiemap() to include the checks for contiguous >> metadata? Or was that too shady/clever to start with ...? :) > > I wouldn't object to having FIEMAP add a flag for metadata blocks. I've always thought it would be useful to be able to query/dump metadata blocks (e.g. indirect/index blocks) and the inode itself. Hm don't we have that already? Hmm... just xattr I guess. In any case it's still a question of whether ext3 extent count should be "fudged" to make blocks separated by metadata look contiguous or not ... -Eric > Cheers, Andreas > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
