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.
A transfer is queued, but if the file has already been transferred to the
remote before, the transfer is skipped. In this case, it needs to perform
any actions it would normally take after finishing the transfer, like
dropping the local object.
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.
The transfer queue can grow larger than 10 when queueing transfers for
files that were just received, as well as requeueing failed transfers.
I probably need to do some work to prevent that, as it could use a lot of
RAM. But for now, cap the number of displayed transfers in the webapp, to
avoid flooding the browser.
I have seen some other programs do this, and think it's pretty cool. Means
you can test wherever it's deployed, as well as at build time.
My other reason for doing it is less happy. Cabal's handling of test suites
sucks, requiring duplicated info, and even when that's done, it fails to
preprocess hsc files here. Building it in avoids that and avoids having
to explicitly tell cabal to enable test suites, which would then make it
link the test executable every time, which is unnecessarily slow.
This also has the benefit that now "make fast test" does a max speed build
and tests it.
The only thing lost is ./ghci
Speed: make fast used to take 20 seconds here, when rebuilding from
touching Command/Unused.hs. With cabal, it's 29 seconds.
Pity that the library does not provide a function to extract the status
code from the StatusCodeException, so when they had to add a new field, it
breaks every single place that does it.
Two fixes. First, and most importantly, relax the isLinkToAnnex check
to only look for /annex/objects/, not [^|/].git/annex/objects. If
GIT_DIR is used with a detached work tree, the git directory is
not necessarily named .git.
There are important caveats with doing that at all, since git-annex will
make symlinks that point at GIT_DIR, which means that the relative path
between GIT_DIR and GIT_WORK_TREE needs to remain stable across all clones
of the repository.
----
The other fix is just fixing crazy and wrong code that, when GIT_DIR is
set, expects to still find a git repository in the path below the work
tree, and uses some of its configuration, and some of GIT_DIR. What was I
thinking, and why can't I seem to get this code right?
In general, git-annex does not try to preserve file permissions. For
example, they don't round trip through special remotes. So it's ok to not
preserve them for git remotes either.
On crippled filesystems, rsync has been observed failing after the file
was transferred because it couldn't set some permission or other.
Adding a file that is already annexed, but has been modified, was broken in
direct mode.
This fix makes the new content be added. It does have the problem that
re-running `git annex add` will checksum and re-add the content repeatedly,
until it's committed. This happens because the key associated with the file
does not change until the new one gets committed, so it keeps thinking the
file has changed.
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!!
In indirect mode, now checks the inode cache to detect changes to a file.
Note that a file can still be changed if a process has it open for write,
after landing in the annex.
In direct mode, some checking of the inode cache was done before, but
from a much later point, so fewer modifications could be detected. Now it's
as good as indirect mode.
On crippled filesystems, no lock down is done before starting to add a
file, so checking the inode cache is the only protection we have.
git annex init probes for crippled filesystems, and sets direct mode, as
well as `annex.crippledfilesystem`.
Avoid manipulating permissions of files on crippled filesystems.
That would likely cause an exception to be thrown.
Very basic support in Command.Add for cripped filesystems; avoids the lock
down entirely since doing it needs both permissions and hard links.
Will make this better soon.
Been meaning to do this for some time; Android port was last straw.
Note that newer versions of the uuid library have a Data.UUID.V4 that
generates random UUIDs slightly more cleanly, but Debian has an old version
of the library, so I do it slightly round-about.
These files were left behind, and made getKeysPresent find keys that were
not present. It would be expensive to make getKeysPresent check that the
actual key files are present (it just lists the directories). But that's not
needed if we just clean up the stale cache and mapping files.
To handle systems that were in direct mode and got switched back with stale
direct mode files, made cleanObjectLoc remove all files in the key's directory.
git annex unused will still list keys that are gone but for which the stale
direct mode files exists. To deal with that, made dropunused remove the key's
directory even if the key does not seem to be present.
Making the pre-commit hook look at git diff-index to find changed direct
mode files and update the mappings works pretty well.
One case where it does not work is when a file is git annex added, and then
git rmed, and then this is committed. That's a no-op commit, so the hook
probably doesn't even run, and it certianly never notices that the file
was deleted, so the mapping will still have the original filename in it.
For this and other reasons, it's important that the mappings still be
treated as possibly inconsistent.
Also, the assistant now allows the pre-commit hook to run when in direct
mode, so the mappings also get updated there.
The most common way for a mapping to be stale is when a file was deleted,
or renamed. Nothing updates the mappings for deletions yet.
But they can also become stale in other ways. For example a file can
be modified.
So, the mapping is not trusted to be consistent. When we get a key,
only replace symlinks that still point to that key with its content.
When we drop a key, only put back symlinks for files that still have
the direct mode content.
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
