From: Dmitry Monakhov Subject: Re: [GIT PULL] ext4 updates for 3.9 Date: Thu, 28 Feb 2013 00:58:55 +0400 Message-ID: <87k3pteank.fsf@openvz.org> References: <20130227154450.GA23402@x4> <20130227170157.GA222@x4> <98C6DE45-F050-4AAD-82E2-7352F5BB0A5D@gmail.com> <20130227172256.GA236@x4> <7BFB2135-A1F0-4B6D-9962-16E75E5560F8@gmail.com> <20130227174553.GA224@x4> <20130227184912.GA19624@thunk.org> <20130227185625.GA224@x4> <20130227191923.GA1121@redhat.com> <20130227192907.GB14253@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Theodore Ts'o , Dave Jones , Markus Trippelsdorf , Linus Torvalds , "gnehzuil.liu" , Zheng Liu , Borislav Petkov , "linux-ext4\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" Return-path: In-Reply-To: <20130227192907.GB14253@thunk.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed, 27 Feb 2013 14:29:07 -0500, Theodore Ts'o wrote: > On Wed, Feb 27, 2013 at 02:19:23PM -0500, Dave Jones wrote: > > > > Looks like it's fixed here too. > > > > How did this make it through -next without anyone hitting it ? > > > > I can't remember how many years ago I last bought a disk < 1TB, > > and I can't be alone. Or is everyone all about SSDs these days? > > I use LVM, so I have a number of volues which are smaler than 512GB, > but very few which are actually larger than 1TB. And none on my test > boxes. I was running the bleeding edge ext4 code on my laptop as for > dogfooding purposes, but I have an 80GB mSATA SSD and a 500GB HDD on > my X230 laptop (it requires a thin laptop drive, and 7mm drives don't > come any bigger, alas). > > > Is anyone running xfstests or similar on linux-next regularly ? > > I run xfstests on the ext4 tree, and I ran it on ext4 plus Linus's tip > before I submitted a pull request. The problem is that XFSTESTS is > S-L-O-W if you use large partitions, so typically I use a 5GB Indeed. That's why i give-up rotated disks and run xfstest only on SSD or brd module > partition sizes for my test runs. Normally we're worried about race > condition bugs, not something as bone-headed as a bitmasking problem, > so it makes sense to use a smaller disk for most of your testing. > (Some folks do their xfstests run on SSD's or tmpfs image files, again > for speed reasons, and it's unlikely they would be big enough.) > > So what we probably need to do is to have a separate set of tests > using a loopback mount, and perhaps an artificially created file > system which has a large percentage of the blocks in the middle of the > file system busied out, to make efficient testing of these sorts of > bugs more efficient. As I said, I'm thinking about how's the best way > to improve our testing regime to catch such problems the next time around. Amazing idea. Something like: #dd if=/dev/zero of=/tmp/fs.img bs=1M seek=2000000 count=1 #mkfs.ext4 -m0 -i4096000 /tmp/fs.img #mount /tmp/fs.img /mnt/ -oloop #for ((i=0; i < 2000; i++));do fallocate -l $((1024*1024*1024)) /mnt/f$i ;done #for ((i=0; i < 2000; i++));do truncate -s $((1023*1024*1024)) /mnt/f$i ;done As result file system image has 2gb of free space wich is fragmented to ~2000 chunks 1Mb each. But image itself is quite small # df /mnt Filesystem 1K-blocks Used Available Use% Mounted on /dev/loop0 2047678076 2045679228 1998848 100% /mnt # du -sch /tmp/fs.img 242M /tmp/fs.img 242M total Later we can simply run xfstest/fio/fsx on this image. I'll prepare new xfstest based on that idea. But the only disadvantage is that loop dev has bottleneck, all requests will be serialized on i_mutex. > > Cheers, > > - Ted > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html