Batch detection is heuristic, so can sometimes fail. I observed one such
failure while starting up in a repository with 87000 files. After the first
several batches of ~5000 files, it fell out of batch mode, and never
re-entered it, and so made many more commits of a few files at a time
than necessary.
So, let's always use batch mode when in the startup scan. This avoids the
heuristic there, at least.
There is clearly also room to improve the heuristic. Possibly 10 files is
too high a bar to be found during a commit, on a system that can commit
quickly.
Extends the index.lock handling to other git lock files. I surveyed
all lock files used by git, and found more than I expected. All are
handled the same in git; it leaves them open while doing the operation,
possibly writing the new file content to the lock file, and then closes
them when done.
The gc.pid file is excluded because it won't affect the normal operation
of the assistant, and waiting for a gc to finish on startup wouldn't be
good.
All threads except the webapp thread wait on the new startup sanity checker
thread to complete, so they won't try to do things with git that fail
due to stale lock files. The webapp thread mostly avoids doing that kind of
thing itself. A few configurators might fail on lock files, but only if the
user is explicitly trying to run them. The webapp needs to start
immediately when the user has opened it, even if there are stale lock
files.
Arranging for the threads to wait on the startup sanity checker was a bit
of a bear. Have to get all the NotificationHandles set up before the
startup sanity checker runs, or they won't see its signal. Perhaps
the NotificationBroadcaster is not the best interface to have used for
this. Oh well, it works.
This commit was sponsored by Michael Jakl
Requires git 1.8.4 or newer. When it's installed, a background
git check-ignore process is run, and used to efficiently check ignores
whenever a new file is added.
Thanks to Adam Spiers, for getting the necessary support into git for this.
A complication is what to do about files that are gitignored but have
been checked into git anyway. git commands assume the ignore has been
overridden in this case, and not need any more overriding to commit a
changed version.
However, for the assistant to do the same, it would have to run git ls-files
to check if the ignored file is in git. This is somewhat expensive. Or it
could use the running git-cat-file process to query the file that way,
but that requires transferring the whole file content over a pipe, so it
can be quite expensive too, for files that are not git-annex
symlinks.
Now imagine if the user knows that a file or directory tree will be getting
frequent changes, and doesn't want the assistant to sync it, so gitignores
it. The assistant could overload the system with repeated ls-files checks!
So, I've decided that the assistant will not automatically commit changes
to files that are gitignored. This is a tradeoff. Hopefully it won't be a
problem to adjust .gitignore settings to not ignore files you want the
assistant to autocommit, or to manually git annex add files that are listed
in .gitignore.
(This could be revisited if git-annex gets access to an interface to check
the content of the index w/o forking a git command. This could be libgit2,
or perhaps a separate git cat-file --batch-check process, so it wouldn't
need to ship over the whole file content.)
This commit was sponsored by Francois Marier. Thanks!
This fixes a bug with git annex add in direct mode. If some files already
existed in the tree pointing at the same key as a file that was just added,
and their content was not present, add neglected to copy the content to
those files.
I also changed the behavior of moveAnnex slightly: When content is moved
into the annex in direct mode, it does not overwrite any content already
present in direct mode files. That content may be modified after all.
That hook updates associated file bookkeeping info for direct mode.
But, everything already called addAssociatedFile when adding/changing a
file. It only needed to also call removeAssociatedFile when deleting a file,
or a directory.
This should make bulk adds faster, by some possibly significant amount.
Bulk removals may be a little slower, since it has to use catKeyFile now
on each removed file, but will still be faster than adds.
* since this is a crippled filesystem anyway, git-annex doesn't use
symlinks on it
* so there's no reason to use the mixed case hash directories that we're
stuck using to avoid breaking everyone's symlinks to the content
* so we can do what is already done for all bare repos, and make non-bare
repos on crippled filesystems use the all-lower case hash directories
* which are, happily, all 3 letters long, so they cannot conflict with
mixed case hash directories
* so I was able to 100% fix this and even resuming `git annex add` in the
test case will recover and it will all just work.
This avoids commit churn by the assistant when eg,
replacing a file with a symlink.
But, just as importantly, it prevents the working tree being left with a
deleted file if git-annex, or perhaps the whole system, crashes at the
wrong time.
(It also probably avoids confusing displays in file managers.)
My test case for this bug is to have the assistant running and syncing to
a remote, and create a file in the annex. Then at the command line run
git annex drop. The assistant sees that the file is gone, sees it's a wanted
file, and downloads it from the remote.
With a directory special remote and a small file, I was seeing around 1
time in 3, a race where the file got unstaged from git after it got
downloaded.
Looking at what direct mode content managing code does in this case, it
deletes the symlink, and then adds the file content back. It would be
possible, sometimes, to avoid removing the symlink and do this atomically.
And I probably should.. but in some cases, particularly where the file
needs to be run through `cp` (multiple direct mode files with same
content), there's no way to atomically replace the symlink with the
content.
Anyway, the bug turns out to be something that the watcher does right for
indirect mode, but not for direct mode. When it got an add event, it
checked to see if this was a new file, or one we've already added. In the
latter case, no add event was queued. But that means that only the rm event
is queued, and so it unstages the file.
Fixed by queueing an add event even when the file is already in git.
Tested by running hundreds of drops in a loop; file remained staged.
I would have sort of liked to put this in .gitattributes, but it seems
it does not support multi-word attribute values. Also, making this a single
config setting makes it easy to only parse the expression once.
A natural next step would be to make the assistant `git add` files that
are not annex.largefiles. OTOH, I don't think `git annex add` should
`git add` such files, because git-annex command line tools are
not in the business of wrapping git command line tools.
This cleaned up the code quite a bit; now the committer just looks at the
Change to see if it's a change that needs to have a transfer queued for it.
If I later want to add dropping keys for files that were removed, or
something like that, this should make it straightforward.
This also fixes a bug. In direct mode, moving a file out of an archive
directory failed to start a transfer to get its content. The problem
was that the file had not been committed to git yet, and so the transfer
code didn't want to touch it, since fileKey failed to get its key.
Only starting transfers after a commit avoids this problem.
Watcher wants to rewrite symlink to fix it. But in direct mode, the symlink
could be replaced at any time with file content that has finished being
transferred by some other process. So, just don't touch it.
FWIW, I audited the rest of the assistant for places where it removes
files, and the rest is ok. I have not audited the rest of git-annex.
assistant: Fix bug in direct mode that could occur when a symlink is moved
out of an archive directory, and resulted in the file not being set to
direct mode when it was transferred.
The bug was that the direct mode mapping was not up-to-date when the
transferrer finished. So, finding no direct mode place to store the object,
it was put into .git/annex in indirect mode.
To fix this, just make the watcher update the direct mode mapping to
include the new file before it starts the transfer. (Seems we don't need to
update it to remove the old file if the link was moved, because the direct
mode code will notice it's not present and the mapping gets updated for its
removal later.)
The reason this was a race, and was probably not seen often is because
the committer came along and updated the direct mode mapping as part of
adding the moved symlink. But when the file was sufficiently small or
the remote sufficiently fast, this could happen after the transfer
finished.
Refactored annex link code into nice clean new library.
Audited and dealt with calls to createSymbolicLink.
Remaining calls are all safe, because:
Annex/Link.hs: ( liftIO $ createSymbolicLink linktarget file
only when core.symlinks=true
Assistant/WebApp/Configurators/Local.hs: createSymbolicLink link link
test if symlinks can be made
Command/Fix.hs: liftIO $ createSymbolicLink link file
command only works in indirect mode
Command/FromKey.hs: liftIO $ createSymbolicLink link file
command only works in indirect mode
Command/Indirect.hs: liftIO $ createSymbolicLink l f
refuses to run if core.symlinks=false
Init.hs: createSymbolicLink f f2
test if symlinks can be made
Remote/Directory.hs: go [file] = catchBoolIO $ createSymbolicLink file f >> return True
fast key linking; catches failure to make symlink and falls back to copy
Remote/Git.hs: liftIO $ catchBoolIO $ createSymbolicLink loc file >> return True
ditto
Upgrade/V1.hs: liftIO $ createSymbolicLink link f
v1 repos could not be on a filesystem w/o symlinks
Audited and dealt with calls to readSymbolicLink.
Remaining calls are all safe, because:
Annex/Link.hs: ( liftIO $ catchMaybeIO $ readSymbolicLink file
only when core.symlinks=true
Assistant/Threads/Watcher.hs: ifM ((==) (Just link) <$> liftIO (catchMaybeIO $ readSymbolicLink file))
code that fixes real symlinks when inotify sees them
It's ok to not fix psdueo-symlinks.
Assistant/Threads/Watcher.hs: mlink <- liftIO (catchMaybeIO $ readSymbolicLink file)
ditto
Command/Fix.hs: stopUnless ((/=) (Just link) <$> liftIO (catchMaybeIO $ readSymbolicLink file)) $ do
command only works in indirect mode
Upgrade/V1.hs: getsymlink = takeFileName <$> readSymbolicLink file
v1 repos could not be on a filesystem w/o symlinks
Audited and dealt with calls to isSymbolicLink.
(Typically used with getSymbolicLinkStatus, but that is just used because
getFileStatus is not as robust; it also works on pseudolinks.)
Remaining calls are all safe, because:
Assistant/Threads/SanityChecker.hs: | isSymbolicLink s -> addsymlink file ms
only handles staging of symlinks that were somehow not staged
(might need to be updated to support pseudolinks, but this is
only a belt-and-suspenders check anyway, and I've never seen the code run)
Command/Add.hs: if isSymbolicLink s || not (isRegularFile s)
avoids adding symlinks to the annex, so not relevant
Command/Indirect.hs: | isSymbolicLink s -> void $ flip whenAnnexed f $
only allowed on systems that support symlinks
Command/Indirect.hs: whenM (liftIO $ not . isSymbolicLink <$> getSymbolicLinkStatus f) $ do
ditto
Seek.hs:notSymlink f = liftIO $ not . isSymbolicLink <$> getSymbolicLinkStatus f
used to find unlocked files, only relevant in indirect mode
Utility/FSEvents.hs: | Files.isSymbolicLink s = runhook addSymlinkHook $ Just s
Utility/FSEvents.hs: | Files.isSymbolicLink s ->
Utility/INotify.hs: | Files.isSymbolicLink s ->
Utility/INotify.hs: checkfiletype Files.isSymbolicLink addSymlinkHook f
Utility/Kqueue.hs: | Files.isSymbolicLink s = callhook addSymlinkHook (Just s) change
all above are lower-level, not relevant
Audited and dealt with calls to isSymLink.
Remaining calls are all safe, because:
Annex/Direct.hs: | isSymLink (getmode item) =
This is looking at git diff-tree objects, not files on disk
Command/Unused.hs: | isSymLink (LsTree.mode l) = do
This is looking at git ls-tree, not file on disk
Utility/FileMode.hs:isSymLink :: FileMode -> Bool
Utility/FileMode.hs:isSymLink = checkMode symbolicLinkMode
low-level
Done!!
New setting, can be used to disable autocommit of changed files by the
assistant, while it still does data syncing and other tasks.
Also wired into webapp UI
It used to not log to daemon.log when a repository was first created, and
when starting the webapp. Now both do. Redirecting stdout and stderr to the
log is tricky when starting the webapp, because the web browser may want to
communicate with the user. (Either a console web browser, or web.browser = echo)
This is handled by restoring the original fds when running the browser.
The expensive scan uses lookupFile, but in direct mode, that doesn't work
for files that are present. So the scan was not finding things that are
present that need to be uploaded. (It did find things not present that
needed to be downloaded.)
Now lookupFile also works in direct mode. Note that it still prefers
symlinks on disk to info committed to git, in direct mode. This is
necessary to make things like Assistant.Threads.Watcher.onAddSymlink
work correctly, when given a new symlink not yet checked into git (or
replacing a file checked into git).
When a file is changed in direct mode, the old content is probably lost
(at least from the local repo), and bookeeping needs to be updated to
reflect this.
Also, synthetic add events are generated at assistant startup, so
make it detect when the file has not really changed, and avoid re-adding
it.
This does add the overhead of querying the runing git cat-file for the
key that's recorded in git for the file, each time a file is added or
modified in direct mode.
git add --update cannot be used, because it'll stage typechanged direct
mode files. Intead, use ls-files to find deleted files, and stage them
ourselves.
It seems that no commit was made before when the scan staged deleted files.
(Probably masked since if files were added, a commit happened then..)
Now that I'm doing the staging, I was also able to fix that bug.
This allows it to use Build.SysConfig to always install the programs
configure detected. Amoung other fixes, this ensures the right uuid
generator and checksum programs are installed.
I also cleaned up the handling of lsof's path; configure now checks for
it in PATH, but falls back to looking for it in sbin directories.
Currently have three old versions of functions that more reworking is
needed to remove: getDaemonStatusOld, modifyDaemonStatusOld_, and
modifyDaemonStatusOld
This is a nice win; much less code runs in Annex, so other threads have
more chances to run concurrently.
I do notice that renaming a file has gone from 1 to 2 commits. I think this
is due to the above improvement letting the committer run more frequently,
so it commits the rm first.
Converted several threads to run in the monad.
Added a lot of useful combinators for working with the monad.
Now the monad includes the name of the thread.
Some debugging messages are disabled pending converting other threads.
This can result in the file being dropped, or being downloaded, or even
being dropped from some other repo.
It's even possible to create a file in a directory where content is not
wanted, which will make the assistant immediately send it elsewhere, and
then drop it.
Makes it safe to use git annex unlock with the watcher/assistant.
And also to mix use of the watcher/assistant with regular files stored in git.
Long ago, I had avoided doing this check, except during the startup scan,
because it would be slow to run ls-files repeatedly.
But then I added the lsof check, and to make that fast, got it to detect
batch file adds. So let's move the ls-files check to also occur when it'll
have a batch, and can check them all with one call.
This does slow down adding a single file by just a bit, but really only
a little bit. (The lsof check is probably more expensive.) It also
speeds up the startup scan, especially when there are lots of new files
found by the scan.
Also, fixed the sleep for annex.delayadd to not run while the threadstate
lock is held, so it doesn't unnecessarily freeze everything else.
Also, --force no longer makes it skip the lsof check, which was not
documented, and seems never a good idea.
This is handled differently for inotify, which can track modifications of
existing files, and kqueue, which cannot (TTBOMK). On the inotify side,
the TransferWatcher just waits for the file to be updated and reads the new
bytesComplete. On the kqueue side, the TransferPoller has to re-read the
file every update (currently 0.5 seconds, might need to increase that).
I did think about working around kqueue's limitations by somehow creating
a new file each time the size changed. But cleaning up all the files that
would result seemed difficult. And really, this is not a lot worse than
the TransferWatcher's behavior for downloads, which stats a file every 0.5
seconds. As long as the OS has decent file caching behavior..
I've convinced myself that nothing in DaemonStatus can deadlock,
as it always keepts the TMVar full. That was the only reason it was in the
Annex monad.
There's still a bug; if the child updates its transfer info file,
then the data from it will superscede the TransferInfo, losing the
info that we should wait on this child.
The reason the DirWatcher had to wait for program termination was because
it used withINotify, so when it finished, its watcher threads were killed.
But since I have two DirWatcher threads now, that was not good, and could
perhaps explain the MVar problem I saw yesterday. In any case, fixed this
part of the code by making the DirWatcher return a handle that can be used
to stop it, and now the main Assistant thread is the only one calling
waitForTermination.
