On 2020/09/09 19:26, Johannes Thumshirn wrote: > Document the newly introduced explicit-open mount option. > > Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> > > --- > Changes to v1: > - Address Randy's comments > --- > Documentation/filesystems/zonefs.rst | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/Documentation/filesystems/zonefs.rst b/Documentation/filesystems/zonefs.rst > index 6c18bc8ce332..6b213fe9a33e 100644 > --- a/Documentation/filesystems/zonefs.rst > +++ b/Documentation/filesystems/zonefs.rst > @@ -326,6 +326,21 @@ discover the amount of data that has been written to the zone. In the case of a > read-only zone discovered at run-time, as indicated in the previous section. > The size of the zone file is left unchanged from its last updated value. > > +A zoned block device (e.g. an NVMe Zoned Namespace device) may have limits on > +the number of zones that can be active, that is, zones that are in the > +implicit open, explicit open or closed conditions. This potential limitation > +translates into a risk for applications to see write IO errors due to this > +limit being exceeded if the zone of a file is not already active when a write > +request is issued by the user. > + > +To avoid these potential errors, the "explicit-open" mount option forces zones > +to be made active using an open zone command when a file is opened for writing > +for the first time. If the zone open command succeeds, the application is then > +guaranteed that write requests can be processed. Conversely, the > +"explicit-open" mount option will result in a zone close command being issued > +to the device on the last close() of a zone file if the zone is not full nor > +empty. > + > Zonefs User Space Tools > ======================= > > Looks good. Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx> -- Damien Le Moal Western Digital Research
