On Tue, Jan 6, 2015 at 8:44 AM, Sage Weil <sweil@xxxxxxxxxx> wrote: > Hey, > > In an exchange on linux-fsdevel yesterday it became clear that even when > FIEMAP isn't buggy it's not a good interface to build a map of sparse > files. For example, XFS defrag or other future fs features may muck with > fiemap results. One wouldn't expect those things to change whether a file > extent is allocated or not allocated, but given what we've seen so far I > wouldn't bet on it. > > Instead, we should use lseek SEEK_DATA/SEEK_HOLE, which is a more natural > interface for what we need. This should simply be a matter of replacing > the fiemap() method implementation in FileStore.cc, I think. > > See this thread: > > http://marc.info/?l=linux-fsdevel&m=142050204317588&w=2 > > The other half of this is we should confirm that xfstests.git has good > SEEK_HOLE/SEEK_DATA stress tests (that verify correct results on both > recently written, recently synced, and uncached files). Is there a ticket covering this? :) -Greg -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
