Merge branch 'master' into watch

Command/InitRemote.hs

@@ -15,6 +15,7 @@ import qualified Remote
 import qualified Logs.Remote
 import qualified Types.Remote as R
 import Annex.UUID
+import Logs.UUID
 
 def :: [Command]
 def = [command "initremote"
@@ -60,6 +61,7 @@ findByName name = do
 	where
 		generate = do
 			uuid <- liftIO genUUID
+			describeUUID uuid name
 			return (uuid, M.insert nameKey name M.empty)
 
 findByName' :: String ->  M.Map UUID R.RemoteConfig -> Maybe (UUID, R.RemoteConfig)

Remote.hs

@@ -54,9 +54,9 @@ remoteMap :: (Remote -> a) -> Annex (M.Map UUID a)
 remoteMap c = M.fromList . map (\r -> (uuid r, c r)) .
 	filter (\r -> uuid r /= NoUUID) <$> remoteList
 
-{- Map of UUIDs and their descriptions.
+{- Map of UUIDs of remotes and their descriptions.
  - The names of Remotes are added to suppliment any description that has
- - been set for a repository. -}
+ - been set for a repository.  -}
 uuidDescriptions :: Annex (M.Map UUID String)
 uuidDescriptions = M.unionWith addName <$> uuidMap <*> remoteMap name
 
@@ -101,9 +101,6 @@ nameToUUID n = byName' n >>= go
 		double (a, _) = (a, a)
 
 {- Pretty-prints a list of UUIDs of remotes, for human display.
- -
- - Shows descriptions from the uuid log, falling back to remote names,
- - as some remotes may not be in the uuid log.
  -
  - When JSON is enabled, also generates a machine-readable description
  - of the UUIDs. -}

debian/changelog

@@ -5,6 +5,7 @@ git-annex (3.20120606) UNRELEASED; urgency=low
     to manually run git commands when manipulating files.
   * add: Prevent (most) modifications from being made to a file while it
     is being added to the annex.
+  * initremote: Automatically describe a remote when creating it.
 
  -- Joey Hess <joeyh@debian.org>  Tue, 05 Jun 2012 20:25:51 -0400
 

doc/design/assistant/blog/day_3__more_races.mdwn

@@ -0,0 +1,26 @@
+Today I worked on the race conditions, and fixed two of them. Both
+were fixed by avoiding using `git add`, which looks at the files currently
+on disk. Instead, `git annex watch` injects symlinks directly into git's
+index, using `git update-index`.
+
+There is one bad race condition remaining. If multiple processes have a
+file open for write, one can close it, and it will be added to the annex.
+But then the other can still write to it.
+
+----
+
+Getting away from race conditions for a while, I made `git annex watch`
+not annex `.gitignore` and `.gitattributes` files.
+
+And, I made it handle running out of inotify descriptors. By default,
+`/proc/sys/fs/inotify/max_user_watches` is 8192, and that's how many
+directories inotify can watch. Now when it needs more, it will print
+a nice message showing how to increase it with `sysctl`.
+
+FWIW, DropBox also uses inotify and has the same limit. It seems to not
+tell the user how to fix it when it goes over. Here's what `git annex
+watch` will say:
+
+	Too many directories to watch! (Not watching ./dir4299)
+	Increase the limit by running:
+	  echo fs.inotify.max_user_watches=81920 | sudo tee -a /etc/sysctl.conf; sudo sysctl -p

doc/design/assistant/blog/day_3__more_races/comment_1_d6015338f602b574a3805de5481fc45e._comment

@@ -0,0 +1,8 @@
+[[!comment format=mdwn
+ username="https://www.google.com/accounts/o8/id?id=AItOawkmtR6oVColYKoU0SjBORLDGrwR10G-mKo"
+ nickname="Jo-Herman"
+ subject="Dropbox Inotify"
+ date="2012-06-06T22:03:29Z"
+ content="""
+Actually, Dropbox giver you a warning via libnotify inotify. It tends to go away too quickly to properly read though, much less actually copy down the command...
+"""]]

doc/design/assistant/blog/day_3__more_races/comment_2_4d6b23fc6442e0ee0303523cb69d0fba._comment

@@ -0,0 +1,8 @@
+[[!comment format=mdwn
+ username="http://joeyh.name/"
+ ip="4.252.8.36"
+ subject="comment 2"
+ date="2012-06-06T23:25:57Z"
+ content="""
+When I work on the [[webapp]], I'm planning to make it display this warning, and any other similar warning messages that might come up.
+"""]]

doc/design/assistant/blog/day_3__more_races/comment_3_03f5b2344c2a47dea60086f217d60f9b._comment

@@ -0,0 +1,14 @@
+[[!comment format=mdwn
+ username="https://www.google.com/accounts/o8/id?id=AItOawnBJ6Dv1glxzzi4qIzGFNa6F-mfHIvv9Ck"
+ nickname="Jim"
+ subject="Wording"
+ date="2012-06-07T03:43:19Z"
+ content="""
+For the unfamiliar, it's hard to tell if a command like that would persist.  I'd suggest being as clear as possible, e.g.:
+
+    Increase the limit for now by running:
+      sudo sysctl fs.inotify.max_user_watches=81920
+    Increase the limit now and automatically at every boot by running:
+      echo fs.inotify.max_user_watches=81920 | sudo tee -a /etc/sysctl.conf; sudo sysctl -p
+
+"""]]

doc/design/assistant/blog/day_3__more_races/comment_4_860e90e989ec022100001c65e353a91e._comment

@@ -0,0 +1,8 @@
+[[!comment format=mdwn
+ username="http://joeyh.name/"
+ ip="4.252.8.36"
+ subject="comment 4"
+ date="2012-06-07T04:48:15Z"
+ content="""
+Good thought Jim. I've done something like that.
+"""]]

doc/design/assistant/inotify.mdwn

@@ -19,23 +19,22 @@ really useful, it needs to:
 - notice deleted files and stage the deletion
   (tricky; there's a race with add since it replaces the file with a symlink..)
   **done**
+- Gracefully handle when the default limit of 8192 inotified directories
+  is exceeded. This can be tuned by root, so help the user fix it.
+  **done**
 - periodically auto-commit staged changes (avoid autocommitting when
   lots of changes are coming in)
 - tunable delays before adding new files, etc
-- Coleasce related add/rm events. See commit
+- coleasce related add/rm events for speed and less disk IO
-  cbdaccd44aa8f0ca30afba23fc06dd244c242075 for some details of the problems
+- don't annex `.gitignore` and `.gitattributes` files **done**
-  with doing this.
-- don't annex `.gitignore` and `.gitattributes` files, but do auto-stage
-  changes to them
 - configurable option to only annex files meeting certian size or
   filename criteria
+- option to check files not meeting annex criteria into git directly
 - honor .gitignore, not adding files it excludes (difficult, probably
   needs my own .gitignore parser to avoid excessive running of git commands
   to check for ignored files)
 - Possibly, when a directory is moved out of the annex location,
   unannex its contents.
-- Gracefully handle when the default limit of 8192 inotified directories
-  is exceeded. This can be tuned by root, so help the user fix it.
 - Support OSes other than Linux; it only uses inotify currently.
   OSX and FreeBSD use the same mechanism, and there is a Haskell interface
   for it,
@@ -67,10 +66,18 @@ Many races need to be dealt with by this code. Here are some of them.
   **Currently unfixed**; This changes content in the annex, and fsck will
   later catch the inconsistency.
 
-  Possible fixes: Somehow track or detect if a file is open for write
+  Possible fixes: 
-  by any processes. Or, when possible, making a copy on write copy
+
-  before adding the file would avoid this.  Or, as a last resort, make
+  * Somehow track or detect if a file is open for write by any processes.
-  an expensive copy of the file and add that.
+  * Or, when possible, making a copy on write copy before adding the file
+    would avoid this.
+  * Or, as a last resort, make an expensive copy of the file and add that.
+  * Tracking file opens and closes with inotify could tell if any other
+    processes have the file open. But there are problems.. It doesn't
+    seem to differentiate between files opened for read and for write.
+    And there would still be a race after the last close and before it's
+    injected into the annex, where it could be opened for write again.
+    Would need to detect that and undo the annex injection or something.
 
 * File is added and then replaced with another file before the annex add
   makes its symlink.
@@ -82,16 +89,14 @@ Many races need to be dealt with by this code. Here are some of them.
 * File is added and then replaced with another file before the annex add
   stages the symlink in git.
 
-  **Currently unfixed**; `git add` will be run on the new file, which is
+  Now fixed; `git annex watch` avoids running `git add` because of this
-  not at all good when it's big. Could be dealt with by using `git
+  race. Instead, it stages symlinks directly into the index, without
-  update-index` to manually put the symlink into the index without git
   looking at what's currently on disk.
 
 * Link is moved, fixed link is written by fix event, but then that is
   removed by the user and replaced with a file before the event finishes.
 
-  **Currently unfixed**: `git add` will be run on the file. Basically same
+  Now fixed; same fix as previous race above.
-  effect as previous race above.
 
 * File is removed and then re-added before the removal event starts.
 

doc/design/assistant/webapp.mdwn

@@ -23,6 +23,8 @@ The webapp is a web server that displays a shiny interface.
 
 * there could be a UI to export a file, which would make it be served up
   over http by the web app
+* Display any relevant warning messages. One is the `inotify max_user_watches`
+  exceeded message.
 
 ## implementation
 

doc/tips/using_box.com_as_a_special_remote.mdwn

@@ -24,7 +24,7 @@ With a little setup, git-annex can use Box as a
 * Create `~/.davfs2/davfs2.conf` with some important settings:
 
         mkdir ~/.davfs2/
-        echo use_locks 0 >> ~/.davfs2/davfs2.conf
+        echo use_locks 0 > ~/.davfs2/davfs2.conf
         echo cache_size 1 >> ~/.davfs2/davfs2.conf
         echo delay_upload 0 >> ~/.davfs2/davfs2.conf