git-annex get when run as the first git-annex command in a new repo did not
populate unlocked files. (Reversion in version 8.20210621)
I am not entirely happy with this, because I don't understand how
428c91606b caused the problem in the first
place, and I don't fully understand how skipping calling scanAnnexedFiles
during autoinit avoids the problem.
Kept the explicit call to scanAnnexedFiles during git-annex init,
so that when reconcileStaged is expensive, it can be made to run then,
rather than at some later point when the information is needed.
Sponsored-by: Brock Spratlen on Patreon
The pass was needed to populate files when annex.thin was set,
but in commit 73e0cbbb19,
reconcileStaged started to do that. So, this second pass is not needed
any longer.
I'm now reasonably sure I've identified both cases where this can
happen. v8 upgrades and certian filesystems eg NFS. Both are handled as
well as can be, though it may involve some extra checksumming work.
Eg, showImprecise 1 1.99 returned "1.1" rather than "2". The 9 rounded
upward to 10, and that was wrongly used as the decimal, rather than
carrying the 1.
Sponsored-by: Jack Hill on Patreon
An easy way to see this in action is to have an unlocked file, and touch the
object file.
While all code that compares inode caches for object files needs to be
prepared for this kind of problem and fall back to verification, having
fsck notice it and correct it is cheap (as long as fsck is being run
anyway) and ensures that if it happens for some unusual reason, there's a
way for the user to notice that it's happening.
Not that, when annex.thin is in use, the earlier call to isUnmodified
(and also potentially earlier calls to inAnnex in eg, verifyLocationLog)
will fix up the same problem silently. That might prevent the warning
being displayed, although probably it still will be, because the
Database.Keys write of the InodeCache will be queued but will not have
happened yet. I can't see a way to improve this, but it's not great.
Sponsored-by: Dartmouth College's Datalad project
This avoids it calling enteringStage VerifyStage when it's used in
places that only fall back to verification rarely, and which might be
called while in TransferStage and be going to perform a transfer after
the verification.
This is a result of an audit of every use of getInodeCaches,
to find places that misbehave when the annex object is not in the inode
cache, despite pointer files for the same key being in the inode cache.
Unfortunately, that is the case for objects that were in v7 repos that
upgraded to v8. Added a note about this gotcha to getInodeCaches.
Database.Keys.reconcileStaged, then annex.thin is set, would fail to
populate pointer files in this situation. Changed it to check if the
annex object is unmodified the same way inAnnex does, falling back to a
checksum if the inode cache is not recorded.
Sponsored-by: Dartmouth College's Datalad project
The goal is that Database.Keys be able to use it; it can't use
Annex.Content.Presence due to an import loop.
Several other things also needed to be moved to Annex.Verify as a
conseqence.
Some uses of linkFromAnnex are inside replaceWorkTreeFile, which was
already safe, but others use it directly on the work tree file, which
was race-prone. Eg, if the work tree file was first removed, then
linkFromAnnex called to populate it, the user could have re-written it in
the interim.
This came to light during an audit of all calls of addInodeCaches,
looking for such races. All the other uses of it seem ok.
Sponsored-by: Brett Eisenberg on Patreon
In Annex.Content, the object file was statted after pointer files were
populated. But if annex.thin is set, once the pointer files are
populated, the object file can potentially be modified via the hard
link. So, it was possible, though seemingly very unlikely, for the inode
of the modified object file to be cached.
Command.Fix and Command.Fsck had similar problems, statting the work
tree files after they were in place. Changed them to stat the temp file
that gets moved into place. This does rely on .git/annex being on the
same filesystem. If it's not, the cached inode will not be the same as
the one that the temp file gets moved to. Result will be that git-annex
will later need to do an expensive verification of the content of the
worktree files. Note that the cross-filesystem move of the temp file
already is a larger amount of extra work, so this seems acceptable.
Sponsored-by: Luke Shumaker on Patreon
Fix bug that caused some transfers to incorrectly fail with "content
changed while it was being sent", when the content was not changed.
While I don't know how to reproduce the problem that several people
reported, it is presumably due to the inode cache somehow being stale.
So check isUnmodified', and if it's not modified, include the file's
current inode cache in the set to accept, when checking for modification
after the transfer.
That seems like the right thing to do for another reason: The failure
says the file changed while it was being sent, but if the object file was
changed before the transfer started, that's wrong. So it needs to check
before allowing the transfer at all if the file is modified.
(Other calls to sameInodeCache or elemInodeCaches, when operating on inode
caches from the database, could also be problimatic if the inode cache is
somehow getting stale. This does not address such problems.)
Sponsored-by: Dartmouth College's Datalad project
When git-annex lock repopulates the object file by copying an associated
file that still has its content, it negected to update the inode cache.
I was not able to actually get this code to successfully repopulate the
object file; the associated file gets replaced with a dangling pointer
before unlock is able to do that. (By what I'm not sure..
reconcileStaged?) Which might be itself a bug, but
anyway this makes me doubtful that this was really leading to a stale
inode cache. Still, in case there is some situation in which it does
work, fixed it to update the inode cache.
Which is the same as the git merge option.
After last commit, this turns out to be needed in the test suite, and when
doing git-annex import from special remote, followed by a git-annex merge.
Sponsored-by: Svenne Krap on Patreon
sync, merge, post-receive: Avoid merging unrelated histories, which used to
be allowed only to support direct mode repositories.
(However, sync does still merge unrelated histories when importing trees
from special remotes, and the assistant still merges unrelated histories
always.)
See 556b2ded2b for why this was added
back in 2016, for direct mode.
This is a behavior change, which might break something that was relying
on sync merging unrelated histories, but git had a good reason to
prevent it, since it's easy to foot shoot with it, and git-annex should
follow suit.
Sponsored-by: Noam Kremen on Patreon
