From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaya Potter Date: Fri Oct 14 00:33:34 2005 Subject: [Ocfs2-devel] ocfs2's bmap output Message-ID: <1129268016.8092.28.camel@localhost.localdomain> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com I'm writing a stackable file system and one of it's features is that it can combine many sparse files into a single view. On ext2/3 I was using bmap to give me the information needed, so for instance, if I created a big sparse file and tacked on some information at the end on ext2/3 I'd get something like blade12:~# ~/a.out abc File: abc Size: 30002 Blocks: 8 Blocksize: 4096 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 833699 where my test program basically calls bmap (or in this case as it's from userspace, it calls the FIBMAP ioctl) on each block of the file. however, when I run it on OCFS2, I get. blade12:/san/lc2# ~/a.out abc File: abc Size: 30002 Blocks: 8 Blocksize: 4096 0 5700288 1 5700289 2 5700290 3 5700291 4 5700292 5 5700293 6 5700294 7 5700295 I'm guessing this is because of its use of extents, and probably means I've screwed myself in trying to use bmap in this way. Is that a correct assumption? Is there any other interface into OCFS2 to tell if a block is a "blank" sparse area? thanks, shaya