From: Tomohiro Kusumi <tkusumi@xxxxxxxxxx> allow_mounted_write= is useful on Linux, but some platforms just return some error on open(2) for mounted devices. # uname Linux # mkfs.ext4 /dev/loop0 > /dev/null mke2fs 1.43.3 (04-Sep-2016) # mount /dev/loop0 /mnt # mount | grep /dev/loop0 /dev/loop0 on /mnt type ext4 (rw,relatime,seclabel,data=ordered) # fio --name=xxxxx --ioengine=sync --rw=write --bs=32k --size=1m --filename=/dev/loop0 xxxxx: (g=0): rw=write, bs=32.0KiB-32.0KiB,32.0KiB-32.0KiB,32.0KiB-32.0KiB, ioengine=sync, iodepth=1 fio-2.18-21-gca205 fio: /dev/loop0 appears mounted, and 'allow_mounted_write' isn't set. Aborting. Run status group 0 (all jobs): # fio --name=xxxxx --ioengine=sync --rw=write --bs=32k --size=1m --filename=/dev/loop0 --allow_mounted_write=1 > /dev/null; echo $? 0 # uname FreeBSD # newfs /dev/da1 > /dev/null # mount /dev/da1 /mnt # mount | grep /dev/da1 /dev/da1 on /mnt (ufs, local) # fio --name=xxxxx --ioengine=sync --rw=write --bs=32k --size=1m --filename=/dev/da1 --allow_mounted_write=1 fio: this platform does not support process shared mutexes, forcing use of threads. Use the 'thread' option to get rid of this warning. xxxxx: (g=0): rw=write, bs=32.0KiB-32.0KiB,32.0KiB-32.0KiB,32.0KiB-32.0KiB, ioengine=sync, iodepth=1 fio-2.18-21-gca205 Starting 1 thread fio: failed opening chardev /dev/da1 for size check file:filesetup.c:654, func=open(/dev/da1), error=Operation not permitted fio: pid=0, err=1/file:filesetup.c:654, func=open(/dev/da1), error=Operation not permitted Run status group 0 (all jobs) Signed-off-by: Tomohiro Kusumi <tkusumi@xxxxxxxxxx> --- HOWTO | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/HOWTO b/HOWTO index c2c6509..e376ea5 100644 --- a/HOWTO +++ b/HOWTO @@ -886,7 +886,8 @@ Target file/device If this isn't set, fio will abort jobs that are destructive (e.g. that write) to what appears to be a mounted device or partition. This should help catch creating inadvertently destructive tests, not realizing that the test will - destroy data on the mounted file system. Default: false. + destroy data on the mounted file system. Note that some platforms don't allow + writing against a mounted device regardless of this option. Default: false. .. option:: pre_read=bool -- 2.9.3 -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
