>> After Linux 5.10, write zeros to a multipath device using >> ioctl(fd, BLKZEROOUT, range) with cache none or directsync will return EBUSY. >> >> Similar to handle_aiocb_write_zeroes_unmap, handle_aiocb_write_zeroes_block >> allow -EBUSY errors during ioctl(fd, BLKZEROOUT, range). >> >> Reference commit in Linux 5.10: >> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=384d87ef2c954fc58e6c5fd8253e4a1984f5fe02 > >But this can happen only when the block device is used by a file system or >maybe someone else. In qemu we assume that we are the only user of the >block device, so EBUSY is a fatal error that should never happen, no? > >Can you explain a real world use case when we get EBUSY? > >Nir >
Please refer to https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_device_mapper_multipath/index Where multipath is configured to a SAN LUN, ioctl(fd, BLKZEROOUT, range) to the /dev/dm-x return EBUSY permanently since Linux 5.10. ChangLimin >> Signed-off-by: ChangLimin <chan...@chinatelecom.cn> >> --- >> block/file-posix.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/block/file-posix.c b/block/file-posix.c >> index 05079b40ca..3e60c96214 100644 >> --- a/block/file-posix.c >> +++ b/block/file-posix.c >> @@ -1629,8 +1629,13 @@ static ssize_t >> handle_aiocb_write_zeroes_block(RawPosixAIOData *aiocb) >> } while (errno == EINTR); >> >> ret = translate_err(-errno); >> - if (ret == -ENOTSUP) { >> + switch (ret) { >> + case -ENOTSUP: >> + case -EINVAL: >> + case -EBUSY: >> s->has_write_zeroes = false; >> + return -ENOTSUP; >> + break; >> } >> } >> #endif >> -- >> 2.27.0 >>
