doc: improve readonly option description

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 4398ffa717843095889b8d2065d5a05769a50acb..e1399b4a101925d94527542e4c5f8f696668912b 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -163,12 +163,12 @@ Command line options
 
 .. option:: --readonly
 
-       Turn on safety read-only checks, preventing writes.  The ``--readonly``
-       option is an extra safety guard to prevent users from accidentally starting
-       a write workload when that is not desired.  Fio will only write if
-       `rw=write/randwrite/rw/randrw` is given.  This extra safety net can be used
-       as an extra precaution as ``--readonly`` will also enable a write check in
-       the I/O engine core to prevent writes due to unknown user space bug(s).
+       Turn on safety read-only checks, preventing writes and trims.  The
+       ``--readonly`` option is an extra safety guard to prevent users from
+       accidentally starting a write or trim workload when that is not desired.
+       Fio will only modify the device under test if
+       `rw=write/randwrite/rw/randrw/trim/randtrim/trimwrite` is given.  This
+       safety net can be used as an extra precaution.
 
 .. option:: --eta=when