### Please describe the problem.

One of my remotes (a USB drive) actually did not have a large number of files that should have been there, according to git annex's records.  When the assistant would try to fetch files from there, it would silently fail and go get them from another remote.  I noticed this behavior and was very puzzled by it.  I eventually went to the command line and started trying to fetch these files.  If I remember correctly, "getting" them would also fail silently.  "git annex whereis" said they were there on the drive.

Finally I did a "git annex fsck --fast" which quickly revealed the problem (several hundred files were gone, all in "archives")

I am not sure how this happened, though I have some vague ideas -- it could be relics of a time when an ordinary directory had been created where a mountpoint for the USB drive should have existed, and it was trying to copy files there.  Or it could have been a side effect of the somewhat confused process where I migrated to a new macbook using OS X's migration assistant and so I suddenly had two copies of the same archive, and some time was spent fiddling around trying to fix that situation up.  Maybe during that point I accidentally flipped that USB repo into being a client instead of a backup repo, and it started dropping archive content, and maybe I stopped it from recording that by impatiently killing what seemed to be a hung git-annex process.... In any case, I don't know how the situation came into existence, but once it existed, the silent failures made it difficult for me to realize that it was happening.  I thought the content really was there (trusting git annex whereis) and it was refusing to transfer it for some reason.

It would have been useful to get some feedback, either in the assistant or the commandline, to the effect that the files which were supposed to be there according to git-annex's information, were not in fact there, and a fsck was called for.

### What steps will reproduce the problem?

Create an annex, with content.  Clone the annex.  Sync.  Delete the files by force from the .git/annex/objects directory in the original.  Go to the clone, and try and "git annex get" the content.  It fails silently.


### What version of git-annex are you using? On what operating system?

    [12:17:03 PM]$ git annex version
    git-annex version: 4.20130709-ga2269ee
    
    build flags: Assistant Webapp Pairing Testsuite S3 WebDAV FsEvents XMPP DNS
    local repository version: 3
    default repository version: 3
    supported repository versions: 3 4 
    upgrade supported from repository versions: 0 1 2

My particular issue has probably existed through a few version upgrades though.

### Please provide any additional information below.

[[!format sh """
# If you can, paste a complete transcript of the problem occurring here.
# If the problem is with the git-annex assistant, paste in .git/annex/daemon.log


# End of transcript or log.
"""]]

> Since neither of us can think of a better behavior for `git annex
> get/copy > --from remote` in this case, I've been reduced to documenting
> it better. The docs now mention that --from will cause it to silently
> skip files that are not present in the specified remote. So, [[done]]
> --[[Joey]]
