On Fri, May 14, 2010 at 05:20:55PM +1000, Dave Chinner wrote: > On Fri, May 14, 2010 at 03:50:54PM +1000, Nick Piggin wrote: > > Now is there really a good reason to go this way and add more to the > > write_begin/write_end paths? Rather than having filesystems just > > implement their own write file_operations in order to do multi-block > > operations? > > Well, if we've got xfs, btrfs, gfs2, ext4, and others all wanting to > do multipage writes, shouldn't we be trying doing in a generic way? If it makes sense, definitely. > Fuse doesn't have to deal with allocation of blocks in > fuse_perform_write() I just can't see how the generic code can really help out with that problem of error handling in various parts of the operation allocation. > > From what I can see, the generic code is not going to be able to be > > much help with error handling etc. so I would prefer to keep it as > > simple as possible. I think it is still adequate for most cases. > > > > Take a look at how fuse does multi-page write operations. It is about > > the simplest case you can get, but it still requires all the generic > > checks etc. > > fuse_perform_write() doesn't do allocation, and so can easily abort > at the first error and just complete the writes that did succeed. > Hence it don't think it's a model that a filesystem that has to > handle space allocation can use. No but it does all the _generic_ vfs checks required, which sounded like what the btrfs folk were concerned about duplicating. My point was just that there isn't very much duplication really. > > and it is quite neat -- I don't see a big issue with > > duplicating generic code? > > When a large number of filesystems end up duplicating the same code, > then we should be looking at how to implement that functionality > generically, right? Yes if it captures a good chunk of common code without unduely complicating things. I'll be interested to see if that can be made the case. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
