On Sat, Apr 19, 2008 at 11:07 PM, Eric Sandeen <sandeen@xxxxxxxxxx> wrote: > Theodore Tso wrote: > > On Sat, Apr 19, 2008 at 01:44:51PM +0400, Alexey Zaytsev wrote: > >> If it is a block containing a metadata object fsck has already read, > >> than we already know what kind of object it is (there must be a way > >> to quickly find all cached objects derived from a given block), and > >> can update the cached version. And if fsck has not yet read the > >> block, it can just be ignored, no matter what kind of data it > >> contains. If it contains metadata and fsck is intrested in it, it > >> will read it sooner or later anyway. If it contains file data, why > >> should fsck even care? > > It seems to me that what the proposed project really does, in essence, > is a read-only check of a filesystem snapshot. It's just that the > snapshot is proposed to be constructed in a complex and non-generic (and > maybe impossible) way. Maybe complex and non-generic, but also quite efficient. Only the actually used matadata is cached, and everything is done in userspace. > > If you really just want to verify a snapshot of the fs at a point in > time, surely there are simpler ways. If the device is on lvm, there's > already a script floating around to do it in automated fasion. (I'd > pondered the idea of introducing META_WRITE (to go with META_READ) and > maybe lvm could do a "metadata-only" snapshot to be lighter weight?) How do you tell data from metadata on this level? > > -Eric > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
