10.5 Several developers simultaneously attempting to run CVS
If several developers try to run CVS at the same
time, one may get the following message:
| | [11:43:23] waiting for bach's lock in /usr/local/cvsroot/foo
|
CVS will try again every 30 seconds, and either
continue with the operation or print the message again,
if it still needs to wait. If a lock seems to stick
around for an undue amount of time, find the person
holding the lock and ask them about the cvs command
they are running. If they aren't running a cvs
command, look in the repository directory mentioned in
the message and remove files which they own whose names
start with `#cvs.rfl',
`#cvs.wfl', or `#cvs.lock'.
Note that these locks are to protect CVS's
internal data structures and have no relationship to
the word lock in the sense used by
RCS—which refers to reserved checkouts
(see section Multiple developers).
Any number of people can be reading from a given
repository at a time; only when someone is writing do
the locks prevent other people from reading or writing.
One might hope for the following property:
If someone commits some changes in one cvs command,
then an update by someone else will either get all the
changes, or none of them.
but CVS does not have this property. For
example, given the files
| | a/one.c
a/two.c
b/three.c
b/four.c
|
if someone runs
and someone else runs cvs update at the same
time, the person running update might get only
the change to `b/three.c' and not the change to
`a/two.c'.
