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authorLinus Torvalds <torvalds@linux-foundation.org>2015-10-09 16:58:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-10-09 16:58:11 -0700
commit0444555670350b419496686f4012b9cef808c105 (patch)
treee9f20837bc0772829c6585ef21d70ee510a0e172 /Documentation
parent175d58cfed70f132b8d4df39e19267ad6094bd16 (diff)
parentb0d3cc011e532d8c9db76cf717bcafa53c135595 (diff)
downloadlinux-0444555670350b419496686f4012b9cef808c105.tar.bz2
Merge tag 'dm-4.3-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull dm fixes from Mike Snitzer: "Three stable fixes: - DM core AB-BA deadlock fix in the device destruction path (vs device creation's DM table swap). - DM raid fix to properly round up the region_size to the next power-of-2. - DM cache fix for a NULL pointer seen while switching from the "cleaner" cache policy. Two fixes for regressions introduced during the 4.3 merge: - request-based DM error propagation regressed due to incorrect changes introduced when adding the bi_error field to bio. - DM snapshot fix to only support snapshots that overflow if the client (e.g. lvm2) is prepared to deal with the associated snapshot status interface change" * tag 'dm-4.3-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm snapshot: add new persistent store option to support overflow dm cache: fix NULL pointer when switching from cleaner policy dm: fix request-based dm error reporting dm raid: fix round up of default region size dm: fix AB-BA deadlock in __dm_destroy()
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/device-mapper/snapshot.txt10
1 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/device-mapper/snapshot.txt b/Documentation/device-mapper/snapshot.txt
index 0d5bc46dc167..ad6949bff2e3 100644
--- a/Documentation/device-mapper/snapshot.txt
+++ b/Documentation/device-mapper/snapshot.txt
@@ -41,9 +41,13 @@ useless and be disabled, returning errors. So it is important to monitor
the amount of free space and expand the <COW device> before it fills up.
<persistent?> is P (Persistent) or N (Not persistent - will not survive
-after reboot).
-The difference is that for transient snapshots less metadata must be
-saved on disk - they can be kept in memory by the kernel.
+after reboot). O (Overflow) can be added as a persistent store option
+to allow userspace to advertise its support for seeing "Overflow" in the
+snapshot status. So supported store types are "P", "PO" and "N".
+
+The difference between persistent and transient is with transient
+snapshots less metadata must be saved on disk - they can be kept in
+memory by the kernel.
* snapshot-merge <origin> <COW device> <persistent> <chunksize>