fsck: Added --distributed and --expire options, for distributed fsck.

2 files changed, 40 insertions, 0 deletions

diff --git a/doc/design/iabackup.mdwn b/doc/design/iabackup.mdwn
index bff7a4953..da437aa19 100644
--- a/doc/design/iabackup.mdwn
+++ b/doc/design/iabackup.mdwn
@@ -134,6 +134,8 @@ It will probably take just a few hours to code.
 With that change, the server can check for files that not enough clients
 have verified they have recently, and distribute them to more clients.
 
+(This is now implemented.)
+
 Note that bad actors can lie about this verification; it's not a proof they
 still have the file. But, a bad actor could prove they have a file, and
 refuse to give it back if the IA needed to restore the backup, too.
diff --git a/doc/git-annex-fsck.mdwn b/doc/git-annex-fsck.mdwn
index cb27fe452..1f5d75f3e 100644
--- a/doc/git-annex-fsck.mdwn
+++ b/doc/git-annex-fsck.mdwn
@@ -53,6 +53,44 @@ With parameters, only the specified files are checked.
 
 	git annex fsck --incremental-schedule 30d --time-limit 5h
 
+* `--distributed`
+
+  Normally, fsck only fixes the git-annex location logs when an inconsistecy
+  is detected. In distributed mode, each file that is checked will result
+  in a location log update noting the time that it was present.
+
+  This is useful in situations where repositories cannot be trusted to
+  continue to exist. By running a periodic distributed fsck, those
+  repositories can verify that they still exist and that the information
+  about their contents is still accurate.
+
+  This is not the default mode, because each distributed fsck increases
+  the size of the git-annex branch. While it takes care to log identical
+  location tracking lines for all keys, which will delta-compress well,
+  there is still overhead in committing the changes. If this causes
+  the git-annex branch to grow too big, it can be pruned using
+  [[git-annex-forget]](1)
+
+* `--expire="[repository:]time`..."
+
+  This option makes the fsck check for location logs of the specified
+  repository that have not been updated by a distributed fsck within the
+  specified time period. Such stale location logs are then thrown out, so
+  git-annex will no longer think that a repository contains data, if it is
+  not participating in distributed fscking.
+  
+  The repository can be specified using the name of a remote,
+  or the description or uuid of the repository. If a time is specified
+  without a repository, it is used as the default value for all
+  repositories. Note that location logs for the current repository are
+  never expired, since they can be verified directly.
+
+  The time is in the form "60d" or "1y". A time of "never" will disable
+  expiration.
+
+  Note that a remote can always run `fsck` later on to re-update the
+  location log if it was expired in error.
+
 * `--numcopies=N`
 
   Override the normally configured number of copies.