On Fri, Oct 17, 2008 at 08:25:52AM -0400, Theodore Tso wrote: > On Fri, Oct 17, 2008 at 06:02:14AM -0400, Theodore Tso wrote: > > Thanks for reminding me about that; I had completely forgotten about > > Andreas' patch. Sure, I'll respin the patch to use his extension. > > I looked more closely at Andreas' patch, and it's really not a good > fit for what we want to do. The problem is that it is designed to > attach arbitrary callbacks on a per transaction basis. Each time you > add a callback you need to allocate a stucture, and then it gets > chained onto a inked list. Yeah, I looked at a similar scheme for the buffer commit callbacks, and I realized that it would be a total pain. So I went with a static callback. > What I added was a dead-simple per-journal commit callback, with no > additional memory allocations (and requirement to do error handling if > the memory allocation fails), no need to take a spinlock before > manually adding the call back to each transaction handle, no need to > search the linked list to see if we have an entry on the linked list > already, etc. And this simple callback can used by a jbd2 client to build the machinery for per-transaction callbacks if they want. Joel -- "We will have to repent in this generation not merely for the vitriolic words and actions of the bad people, but for the appalling silence of the good people." - Rev. Dr. Martin Luther King, Jr. Joel Becker Principal Software Developer Oracle E-mail: joel.becker@xxxxxxxxxx Phone: (650) 506-8127 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
