On Mon, Mar 11, 2019 at 03:54:16PM +0800, Dongli Zhang wrote: > > > On 3/11/19 10:24 AM, Ming Lei wrote: > > Hi, > > > > It is observed that ext4 is corrupted easily by running some workloads > > on QEMU NVMe, such as: > > I cannot reproduce with most recent up-to-date mainline kernel on below qemu > versions: > > - qemu-2.10.2 > - qemu-3.0.0 The qemu in my test is from Fedora 27, and it isn't built by me, and 'qemu-system-x86_64 -version' shows that: QEMU emulator version 2.10.2(qemu-2.10.2-1.fc27) My test VM is actually cloned from the official Fedora 27 Cloud image[1], then run 'dnf update' before starting the test. [1] https://download.fedoraproject.org/pub/fedora/linux/releases/27/CloudImages/x86_64/images/Fedora-Cloud-Base-27-1.6.x86_64.qcow2 > > > > > 1) mkfs.ext4 /dev/nvme0n1 > > > > 2) mount /dev/nvme0n1 /mnt > > > > 3) cd /mnt; git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > > 4) then the following error message may show up: > > > > [ 1642.271816] EXT4-fs error (device nvme0n1): ext4_mb_generate_buddy:747: group 0, block bitmap and bg descriptor inconsistent: 32768 vs 23513 free clusters > > > > Or fsck.ext4 will complain after running 'umount /mnt' > > > > The issue disappears by reverting 6e02318eaea53eaafe6 ("nvme: add support for the > > Write Zeroes command"). > > As above commit is for Write Zeros command, I instrument and add printf at the > beginning of nvme_write_zeros() for qemu-2.10.2. > > nvme_write_zeros() are only called for 47 times during "mount /dev/nvme0n1 /mnt". > > > During "git clone" from torvalds' linux.git, there is no call of nvme_write_zeros(). > > Perhaps there is some special configuration required to trigger the > nvme_write_zeros() on purpose during "git clone" to involve the > nvme_cmd_write_zeroes on kernel side? It can be triggered by random write workloads after mkfs & mount on the nvme. > > My test nvme image is only about 5GB. Mine is 8GB. Thanks, Ming
