On Tue, May 04, 2010 at 10:14:18AM +1000, Dave Chinner wrote: > On Mon, May 03, 2010 at 01:27:02PM -0400, Josef Bacik wrote: > > This is similar to what already happens in the write case. If we have a short > > read while doing O_DIRECT, instead of just returning, fallthrough and try to > > read the rest via buffered IO. BTRFS needs this because if we encounter a > > compressed or inline extent during DIO, we need to fallback on buffered. If the > > extent is compressed we need to read the entire thing into memory and > > de-compress it into the users pages. I have tested this with fsx and everything > > works great. Thanks, > > Won't this mean that any direct IO read that spans EOF (i.e. get a > short read) now attempt a buffered IO (that will fail) before returning? > Hmm yeah you are right. What would be an acceptable way to avoid this, do a if (retval || !count || ppos >= i_size_read(inode)) goto out; type thing? Thanks, Josef -- 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
