Hi Dongyang, Yan, When testing BTRFS with RAID 0 metadata on linux-3.3, we see discard ranges exceeding the end of the block device [1], potentially causing dataloss; when this occurs, filesystem writeback becomes catatonic due to continual resubmission. The reproducer is quite simple [2]. Hope this proves useful... Thanks, Daniel --- [1] attempt to access beyond end of device ram0: rw=129, want=8452072, limit=4096000 ... --- [2] modprobe brd rd_size=2048000 (or boot with ramdisk_size=2048000) mkfs.btrfs -m raid0 /dev/ram0 /dev/ram1 mount /dev/ram0 /mnt -o discard fio testcase umount /mnt --- [3] testcase [global] directory=/mnt rw=randread size=256m ioengine=libaio iodepth=4 invalidate=1 direct=1 [bgwriter] rw=randwrite iodepth=32 [queryA] iodepth=1 ioengine=mmap thinktime=3 [queryB] iodepth=1 ioengine=mmap thinktime=1 [bgupdater] rw=randrw iodepth=16 thinktime=1 size=32m -- Daniel J Blueman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
