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author | Joey Hess <joey@kitenet.net> | 2012-06-14 20:06:43 -0400 |
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committer | Joey Hess <joey@kitenet.net> | 2012-06-14 20:06:43 -0400 |
commit | 06caf52f03de118e08dbe368d431835b5a8e6bd6 (patch) | |
tree | 300682566cede1bc15170175c2754a692443f235 /doc/design/assistant/blog/day_9__correctness.mdwn | |
parent | 6b56abf215701b294895c175499fe0493360427c (diff) |
blog for the day
Diffstat (limited to 'doc/design/assistant/blog/day_9__correctness.mdwn')
-rw-r--r-- | doc/design/assistant/blog/day_9__correctness.mdwn | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/doc/design/assistant/blog/day_9__correctness.mdwn b/doc/design/assistant/blog/day_9__correctness.mdwn new file mode 100644 index 000000000..1fa4c09d0 --- /dev/null +++ b/doc/design/assistant/blog/day_9__correctness.mdwn @@ -0,0 +1,30 @@ + git merge watch_ + +My cursor has been mentally poised here all day, but I've been reluctant to +merge watch into master. It seems solid, but is it correct? I was able to +think up a lot of races it'd be subject to, and deal with them, but did I +find them all? + +Perhaps I need to do some automated fuzz testing to reassure myself. +I looked into using [genbackupdata](http://liw.fi/genbackupdata/) to that +end. It's not quite what I need, but could be +[moved in that direction](http://bugs.debian.org/677542). Or I could write +my own fuzz tester, but it seems better to use someone else's, because +a) laziness and b) they're less likely to have the same blind spots I do. + +My reluctance to merge isn't helped by the known bugs with files that are +either already open before `git annex watch` starts, or are opened by two +processes at once, and confuse it into annexing the still-open file when one +process closes it. + +I've been thinking about just running `lsof` on every file as it's being +annexed to check for that, but in the end, `lsof` is too slow. Since its +check involves trawling through all of /proc, it takes it a good half a +second to check a file, and adding 25 seconds to the time it takes to +process 100 files is just not acceptable. + +But an option that could work is to run `lsof` after a bunch of new files +have been annexed. It can check a lot of files nearly as fast as a single +one. In the rare case that an annexed file is indeed still open, it could +be moved back out of the annex. Then when its remaining writer finally +closes it, another inotify event would re-annex it. |