From: Milan Broz Date: Sun, 13 Mar 2011 23:51:27 +0000 (+0000) Subject: Document loopback device use. X-Git-Tag: upstream/1.6~496 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=762e9afd78ce230afd835466a4e4a74483ed5647;p=platform%2Fupstream%2Fcryptsetup.git Document loopback device use. git-svn-id: https://cryptsetup.googlecode.com/svn/trunk@456 36d66b0a-2a48-0410-832c-cd162a569da5 --- diff --git a/man/cryptsetup.8 b/man/cryptsetup.8 index 136d9cb..6cb262e 100644 --- a/man/cryptsetup.8 +++ b/man/cryptsetup.8 @@ -336,6 +336,14 @@ using /dev/random and /dev/urandom here, see \fP--use-random\fR and \fP--use-ur options. Using /dev/random on system without enough entropy sources can cause \fPluksFormat\fR to block until the requested amount of random data is gathered. See \fPurandom(4)\fR for more information. +.SH NOTES ON LOOPBACK DEVICE USE +Cryptsetup is usually used directly over block device (like disk partition or LVM volume). +However if the device argument is file, cryptsetup tries to allocate loopback device +and map it into this file. This mode requires Linux kernel 2.6.25 or more recent which +supports loop autoclear flag (loop device is cleared on last close automatically). + +When device mapping is active, you can see loop backing file in status command output. +Also see losetup(8). .SH AUTHORS cryptsetup is written by Christophe Saout .br