Hi, Am 15.05.25 um 04:28 schrieb Eric Blake: > +do_test full ignore off full
for me, this one fails irregularly (more than 50% of the time) with: -Destination is full; expected full +Destination is unknown; expected full My file system is ext4 inside a virtual machine. > [I] febner@dev8 ~/repos/qemu/build/tests/qemu-iotests (master) [1]> findmnt > --target . > TARGET SOURCE FSTYPE OPTIONS > /home/febner/repos /dev/sdb ext4 rw,relatime The virtual disk is an LVM image. When the test fails, I consistently get 20975616 bytes rather than 20971520 bytes as the result of disk_usage(), i.e. it has one 4 KiB block more. ls -l will still report 20971520 bytes as the length, qemu-img compare succeeds. After the image creation, i.e. job1, the allocation is still as expected: > +20971520 > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw > +-rw-r--r-- 1 febner febner 20971520 May 21 11:18 > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw Only after mirroring, i.e. job2, it will be larger: > +20975616 > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw > +-rw-r--r-- 1 febner febner 20971520 May 21 11:18 > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw Some more information: > [I] febner@dev8 ~/repos/qemu/tests/qemu-iotests/tests (master)> sudo filefrag > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw > -e > Filesystem type is: ef53 > File size of > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw > is 20971520 (5120 blocks of 4096 bytes) > ext: logical_offset: physical_offset: length: expected: flags: > 0: 0.. 15: 36233216.. 36233231: 16: > 1: 16.. 2047: 36233232.. 36235263: 2032: > unwritten > 2: 2048.. 2559: 36239360.. 36239871: 512: 36235264: > 3: 2560.. 4095: 36239872.. 36241407: 1536: > unwritten > 4: 4096.. 5119: 33792000.. 33793023: 1024: 36241408: > last,unwritten,eof > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw: > 3 extents found Note that one of the offsets is not 4KiB-aligned: > 36239360%4096 > 2048 I suppose that is the reason? > [I] febner@dev8 ~/repos/qemu/tests/qemu-iotests/tests (master)> stat > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw > File: > /home/febner/repos/qemu/build/tests/qemu-iotests/scratch/raw-file-mirror-sparse/t.raw > Size: 20971520 Blocks: 40968 IO Block: 4096 regular file > Device: 8,16 Inode: 4866541 Links: 1 > Access: (0644/-rw-r--r--) Uid: ( 1000/ febner) Gid: ( 1000/ febner) > Access: 2025-05-21 11:18:37.622692254 +0200 > Modify: 2025-05-21 11:18:37.540686997 +0200 > Change: 2025-05-21 11:18:37.540686997 +0200 > Birth: 2025-05-21 11:18:37.463682059 +0200 I also tried it on my host, where the filesystem is ZFS using compression, and there, 'du' will already report a lower value after creating the image, because of compression. And even without compression it seems that preallocation=full on ZFS is somehow async :/ > [I] febner@enia ~/qemu/build/tests/qemu-iotests (master)> qemu-img create > my.raw 20M -f raw -o preallocation=full > Formatting 'my.raw', fmt=raw size=20971520 preallocation=full > [I] febner@enia ~/qemu/build/tests/qemu-iotests (master)> du --block-size=1 > my.raw > 512 my.raw > [I] febner@enia ~/qemu/build/tests/qemu-iotests (master)> du --block-size=1 > my.raw > 20980224 my.raw Best Regards, Fiona
