On 2/27/13 2:58 PM, Dmitry Monakhov wrote: > On Wed, 27 Feb 2013 14:29:07 -0500, Theodore Ts'o <tytso@xxxxxxx> 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. Before anyone does too much work, it would be worth revisiting dchinner's [PATCH 0/10] xfstests: rework large filesystem testing series from July 2012 to see if it meets the needs already. It almost got all reviews, with one sticking point left, AFAICT. -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
