[[!comment format=mdwn
 username="joey"
 subject="""comment 2"""
 date="2017-10-10T17:23:14Z"
 content="""
The write bit is necessary so that the files can be opened in write mode to
lock them. Normally the write bit is temporarily enabled and then disabled
for locking, but in a shared repository, some other user may own the file,
which prevents the user from changing its permissions.

Similarly, the parent directory is not made unwritable in a shared
repository, because other users won't be able to temporarily flip the write
bit on when making changes.

[[!commit 0d432dd1a4f718225c4192d0834a4e0a34b3e4bd]] used the latter as a
rationalle to allow the former.

I suppose it could use separate lock files from the content file, 
as is already done in direct mode. However interaction between different
versions of git-annex with different ideas about locking could result in
`git annex drop` losing data.
"""]]
