mirrors/git-annex
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages 1 Wiki Activity Actions

avoid update-index race

Browse source 
This commit was supported by the NSF-funded DataLad project.
This commit is contained in:
Joey Hess 2018-08-17 16:03:40 -04:00
parent 82c5dd8a01
commit 54d49eeac8
No known key found for this signature in database
GPG key ID: DB12DB0FF05F8F38
7 changed files with 91 additions and 46 deletions
Download patch file Download diff file Expand all files Collapse all files

20
doc/todo/smudge.mdwn
View file

@ -12,26 +12,6 @@ git-annex should use smudge/clean filters. v6 mode
# because it doesn't know it has that name
# git commit clears up this mess
* If the user is getting a file that was not present, and at the same
time overwrites the file with new content, the new content can be staged
accidentially when git-annex runs git update-index on the file.
The race window size has been made fairly small, but still
varies with annex.queuesize, since it filters out modified files
before running git update-index on all queued files. A modification
that occurs after the filter checks the file triggers the race.
Here's how to prevent this race: Lock the index file before running git
update-index. Filter out worktree files that were modified already.
Run git update-index on a copy of the index so it runs despite the lock,
and once it's done, replace the old index with it and drop the lock.
Copying the index would be expensive. Could hard link it on systems that
support them.
Note that git split index files complicate this since there are other
files than the main index file.
* Checking out a different branch causes git to smudge all changed files,
and write their content. This does not honor annex.thin. A warning
message is printed in this case.