From: mulhern Date: Mon, 27 Nov 2017 15:02:39 +0000 (-0500) Subject: dm thin: fix documentation relative to low water mark threshold X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=bdd119a94b74acb4cc720695eac50f01173b7496;hp=396293c0274c394da7e9d19260c632c970656b90 dm thin: fix documentation relative to low water mark threshold commit 9b28a1102efc75d81298198166ead87d643a29ce upstream. Fixes: 1. The use of "exceeds" when the opposite of exceeds, falls below, was meant. 2. Properly speaking, a table can not exceed a threshold. It emphasizes the important point, which is that it is the userspace daemon's responsibility to check for low free space when a device is resumed, since it won't get a special event indicating low free space in that situation. Signed-off-by: mulhern Signed-off-by: Mike Snitzer Signed-off-by: Ben Hutchings --- diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt index 801d9d1cf82b..55faf875ef99 100644 --- a/Documentation/device-mapper/thin-provisioning.txt +++ b/Documentation/device-mapper/thin-provisioning.txt @@ -109,9 +109,11 @@ $low_water_mark is expressed in blocks of size $data_block_size. If free space on the data device drops below this level then a dm event will be triggered which a userspace daemon should catch allowing it to extend the pool device. Only one such event will be sent. -Resuming a device with a new table itself triggers an event so the -userspace daemon can use this to detect a situation where a new table -already exceeds the threshold. + +No special event is triggered if a just resumed device's free space is below +the low water mark. However, resuming a device always triggers an +event; a userspace daemon should verify that free space exceeds the low +water mark when handling this event. Thin provisioning -----------------