From: David Lang Date: Wed, 11 Apr 2007 23:30:19 GMT Subject: Re: [PATCH 5/6] Teach "fsck" not to follow subproject links Message-ID: In-Reply-To: On Wed, 11 Apr 2007, Linus Torvalds wrote: > On Wed, 11 Apr 2007, David Lang wrote: >> >> would it make sense to have a --multiple-project option for fsck that would >> let you specify multiple 'projects' that share a object set and have the >> default checking not do the reachability checks that cause problems in this >> case? > > Well, the thing is, sharing object directories actually makes things > *harder* to check, rather than easier. > > It can be a nice space optimization, and yes, if there really is a lot of > shared state, it can make it much cheaper to do some of the checks, but > right now we have absolutely *no* way for fsck to then do the reachability > check, because there is no way to tell fsck where all the refs are (since > now the refs come in from multiple repositories!) this is why I was suggesting a --multiple-project option to let you tell fsck about all of the repositories that it needs to look for refs in. > So the individual objects get cheaper to fsck (no need to fsck shared > objects over and over again), but the reachability gets much harder to > fsck. agreed. > It's not an insurmountable problem, or even necessarily a very large one, > but it boils down to one very basic issue: > > - nobody seems to actually *use* the shared object directory model! > > The thing is, with pack-files and alternates directories, a lot of the > original reasons for shared object directories simply don't exist.. I suspect that if it coudl be checked it would be used more, especially with the subproject support. David Lang