From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srinivas Eeda Date: Mon, 07 May 2012 19:10:32 -0700 Subject: [Ocfs2-devel] [PATCH 2/3] ocfs2: implement discontiguous localalloc bitmap In-Reply-To: <20120508002256.GD4713@dhcp-172-17-9-228.mtv.corp.google.com> References: <1336432890-18638-1-git-send-email-srinivas.eeda@oracle.com> <1336432890-18638-3-git-send-email-srinivas.eeda@oracle.com> <20120508002256.GD4713@dhcp-172-17-9-228.mtv.corp.google.com> Message-ID: <4FA88098.9070301@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com Joel Becker wrote: > On Mon, May 07, 2012 at 04:21:29PM -0700, Srinivas Eeda wrote: > > > OH MY DOG NO. NEVER EVER DO THIS. You cannot update an old > filesystem on the fly! What about other nodes that are running older > versions of the software? They will crash or corrupt data! The entire > point of feature bits is to make sure all nodes are speaking the same > code. > > NAK NAK NAK > > This explains why you trusted la_rec_count earlier. But that is > broken. When your patches are done, the code should use la_bm_off and > la_bitmap when !DISCONTIG_LA and then use la_rec_count, etc when > DISCONTIG_LA. The only way to transition between them is a tunefs.ocfs2 > operation that walks the filesystem, flushes the bitmap, and then > sets/clears la_rec_count appropriately depending on the direction.. > Please please don't hate me :( ... the changes takes care of old formats as well ... I used the reserved space in the structure so that the code changes will be minimal and still compatible with old file system formats. I agree that we need to have some reserved space still available. So as discussed I'll redo the changes accordingly. Please ignore all the patches. Thanks, --Srini