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authorLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 10:39:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 10:39:18 -0700
commit7272c30b6fbc051bf8a3f3c973e64f230c91c8b3 (patch)
tree0989d2d97282e1f00aaa3575d459fcb5ce0beac1 /Documentation
parent6f51f51582e793ea13e7de7ed6b138f71c51784b (diff)
parent1f4e0ff07980820977f45d6a5dbc81d3bb9ce4d3 (diff)
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Merge tag 'dm-3.6-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm
Pull device-mapper updates from Alasdair G Kergon: - Flip the thin target into new read-only or failed modes if errors are detected; - Handle chunk sizes that are not powers of two in the snapshot and thin targets; - Provide a way for userspace to avoid replacing an already-loaded multipath hardware handler while booting; - Reduce dm_thin_endio_hook slab size to avoid allocation failures; - Numerous small changes and cleanups to the code. * tag 'dm-3.6-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm: (63 commits) dm thin: commit before gathering status dm thin: add read only and fail io modes dm thin metadata: introduce dm_pool_abort_metadata dm thin metadata: introduce dm_pool_metadata_set_read_only dm persistent data: introduce dm_bm_set_read_only dm thin: reduce number of metadata commits dm thin metadata: add dm_thin_changed_this_transaction dm thin metadata: add format option to dm_pool_metadata_open dm thin metadata: tidy up open and format error paths dm thin metadata: only check incompat features on open dm thin metadata: remove duplicate pmd initialisation dm thin metadata: remove create parameter from __create_persistent_data_objects dm thin metadata: move __superblock_all_zeroes to __open_or_format_metadata dm thin metadata: remove nr_blocks arg from __create_persistent_data_objects dm thin metadata: split __open or format metadata dm thin metadata: use struct dm_pool_metadata members in __open_or_format_metadata dm thin metadata: zero unused superblock uuid dm thin metadata: lift __begin_transaction out of __write_initial_superblock dm thin metadata: move dm_commit_pool_metadata into __write_initial_superblock dm thin metadata: factor out __write_initial_superblock ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/device-mapper/striped.txt7
-rw-r--r--Documentation/device-mapper/thin-provisioning.txt24
2 files changed, 26 insertions, 5 deletions
diff --git a/Documentation/device-mapper/striped.txt b/Documentation/device-mapper/striped.txt
index f34d3236b9d..45f3b91ea4c 100644
--- a/Documentation/device-mapper/striped.txt
+++ b/Documentation/device-mapper/striped.txt
@@ -9,15 +9,14 @@ devices in parallel.
Parameters: <num devs> <chunk size> [<dev path> <offset>]+
<num devs>: Number of underlying devices.
- <chunk size>: Size of each chunk of data. Must be a power-of-2 and at
- least as large as the system's PAGE_SIZE.
+ <chunk size>: Size of each chunk of data. Must be at least as
+ large as the system's PAGE_SIZE.
<dev path>: Full pathname to the underlying block-device, or a
"major:minor" device-number.
<offset>: Starting sector within the device.
One or more underlying devices can be specified. The striped device size must
-be a multiple of the chunk size and a multiple of the number of underlying
-devices.
+be a multiple of the chunk size multiplied by the number of underlying devices.
Example scripts
diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt
index f5cfc62b7ad..30b8b83bd33 100644
--- a/Documentation/device-mapper/thin-provisioning.txt
+++ b/Documentation/device-mapper/thin-provisioning.txt
@@ -231,6 +231,9 @@ i) Constructor
no_discard_passdown: Don't pass discards down to the underlying
data device, but just remove the mapping.
+ read_only: Don't allow any changes to be made to the pool
+ metadata.
+
Data block size must be between 64KB (128 sectors) and 1GB
(2097152 sectors) inclusive.
@@ -239,7 +242,7 @@ ii) Status
<transaction id> <used metadata blocks>/<total metadata blocks>
<used data blocks>/<total data blocks> <held metadata root>
-
+ [no_]discard_passdown ro|rw
transaction id:
A 64-bit number used by userspace to help synchronise with metadata
@@ -257,6 +260,21 @@ ii) Status
held root. This feature is not yet implemented so '-' is
always returned.
+ discard_passdown|no_discard_passdown
+ Whether or not discards are actually being passed down to the
+ underlying device. When this is enabled when loading the table,
+ it can get disabled if the underlying device doesn't support it.
+
+ ro|rw
+ If the pool encounters certain types of device failures it will
+ drop into a read-only metadata mode in which no changes to
+ the pool metadata (like allocating new blocks) are permitted.
+
+ In serious cases where even a read-only mode is deemed unsafe
+ no further I/O will be permitted and the status will just
+ contain the string 'Fail'. The userspace recovery tools
+ should then be used.
+
iii) Messages
create_thin <dev id>
@@ -329,3 +347,7 @@ regain some space then send the 'trim' message to the pool.
ii) Status
<nr mapped sectors> <highest mapped sector>
+
+ 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.