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
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.
Looking through the git sources (documentation is unclear),
it seems commit doesn't ever trigger git-gc, mostly fetching and merging
seems to. I cannot easily override the setting in all those places, so
instead set gc.auto in git config when initializing a repository with
the assistant.
This does mean that the user cannot set gc.auto=0 and completely avoid
repacks, as the assistant does it daily. But, it only does it after there
are 100x the default number of loose objects, so this is probably not going
to be too annoying.
This cannot completely guard against a runaway log event, and only runs
every hour anyway, but it should avoid most problems with very
long-running, active assistants using up too much space.
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.
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.
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.
