lwn.git/Documentation/device-mapper/thin-provisioning.txt, branch docs-5.8-2

docs: convert docs to ReST and rename to *.rst

2019-06-14T20:21:04+00:00

The conversion is actually: - add blank lines and indentation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab Acked-by: Bjorn Helgaas Acked-by: Mark Brown Signed-off-by: Jonathan Corbet

dm thin: include metadata_low_watermark threshold in pool status

2018-07-30T15:49:08+00:00

The metadata low watermark threshold is set by the kernel. But the kernel depends on userspace to extend the thinpool metadata device when the threshold is crossed. Since the metadata low watermark threshold is not visible to userspace, upon receiving an event, userspace cannot tell that the kernel wants the metadata device extended, instead of some other eventing condition. Making it visible (but not settable) enables userspace to affirmatively know the kernel is asking for a metadata device extension, by comparing metadata_low_watermark against nr_free_blocks_metadata, also reported in status. Current solutions like dmeventd have their own thresholds for extending the data and metadata devices, and both devices are checked against their thresholds on each event. This lessens the value of the kernel-set threshold, since userspace will either extend the metadata device sooner, when receiving another event; or will receive the metadata lowater event and do nothing, if dmeventd's threshold is less than the kernel's. (This second case is dangerous. The metadata lowater event will not be re-sent, so no further event will be generated before the metadata device is out if space, unless some other event causes userspace to recheck its thresholds.) Signed-off-by: Andy Grover Signed-off-by: Mike Snitzer

dm thin: update stale "Status" Documentation

2018-07-27T19:24:03+00:00

Documentation/device-mapper-/thin-provisioning.txt's "Status" section no longer reflected the current fitness level of DM thin-provisioning. That is, DM thinp is no longer "EXPERIMENTAL". It has since seen considerable improvement, has been fairly widely deployed and has performed in a robust manner. Update Documentation to dispel concern raised by potential DM thinp users. Reported-by: Drew Hastings Signed-off-by: Mike Snitzer

dm thin: update Documentation to clarify when "read_only" is valid

2018-05-10T15:18:49+00:00

Due to user confusion, clarify that it doesn't make sense to try to create a thin-pool with "read_only" mode enabled. Signed-off-by: Mike Snitzer

dm thin: extend thinpool status format string with omitted fields

2018-01-17T14:16:12+00:00

Signed-off-by: mulhern Signed-off-by: Mike Snitzer

dm thin: fixes in thin-provisioning.txt

2018-01-17T14:16:12+00:00

Make the format string for thinpool status more correct. Swap the order of two items to correspond with reality. Signed-off-by: mulhern Signed-off-by: Mike Snitzer

dm thin: document representation of when there is none

2018-01-17T14:16:11+00:00

Signed-off-by: mulhern Signed-off-by: Mike Snitzer

dm thin: fix documentation relative to low water mark threshold

2018-01-17T14:16:10+00:00

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

dm thin: display 'needs_check' in status if it is set

2015-07-16T14:23:50+00:00

There is currently no way to see that the needs_check flag has been set in the metadata. Display 'needs_check' in the thin-pool status if it is set in the thinp metadata. Also, update thinp documentation. Signed-off-by: Mike Snitzer

dm thin: remove stale 'trim' message documentation

2015-04-15T16:10:22+00:00

The 'trim' message wasn't ever implemented. Signed-off-by: Mike Snitzer