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-rw-r--r--Documentation/device-mapper/thin-provisioning.txt14
1 files changed, 10 insertions, 4 deletions
diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt
index 1699a55b7b70..4bcd4b7f79f9 100644
--- a/Documentation/device-mapper/thin-provisioning.txt
+++ b/Documentation/device-mapper/thin-provisioning.txt
@@ -112,9 +112,11 @@ $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.
A low water mark for the metadata device is maintained in the kernel and
will trigger a dm event if free space on the metadata device drops below
@@ -274,7 +276,8 @@ ii) Status
<transaction id> <used metadata blocks>/<total metadata blocks>
<used data blocks>/<total data blocks> <held metadata root>
- [no_]discard_passdown ro|rw
+ ro|rw|out_of_data_space [no_]discard_passdown [error|queue]_if_no_space
+ needs_check|-
transaction id:
A 64-bit number used by userspace to help synchronise with metadata
@@ -394,3 +397,6 @@ ii) Status
If the pool has encountered device errors and failed, the status
will just contain the string 'Fail'. The userspace recovery
tools should then be used.
+
+ In the case where <nr mapped sectors> is 0, there is no highest
+ mapped sector and the value of <highest mapped sector> is unspecified.