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authorJohannes Thumshirn <johannes.thumshirn@wdc.com>2020-09-11 11:56:51 +0300
committerDamien Le Moal <damien.lemoal@wdc.com>2020-09-15 12:32:58 +0300
commit48bfd5c6fac10e10b7066bf4aeb919ed9a4e87d3 (patch)
treea88f651abcfcaaf350de4aff8f110f8f16bd8aa7 /Documentation/filesystems
parentb5c00e975779c3d9e6d530c5481309257d5e4220 (diff)
downloadlinux-48bfd5c6fac10e10b7066bf4aeb919ed9a4e87d3.tar.xz
zonefs: document the explicit-open mount option
Document the newly introduced explicit-open mount option. Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/zonefs.rst15
1 files changed, 15 insertions, 0 deletions
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
=======================