On 03/10/2012 03:34 PM, Anand Avati wrote: > There is a no rule written on stone here. It is good practice to make > copies. Note that for things like iatt structure, you need not > "allocate" and "free" from the heap. Most of the time you can copy to > a structure on the stack, modify and return that. You will see that > for parameters which get modified in the callback (typically > aggregated from multiple subvolumes), most translators have a > "modified" copy inside frame->local. Object-lifecycle management in GlusterFS can be a bit tricky. The two most common patterns I see are that dict_t and similar structures will be *dereferenced* either when the originator's (i.e. FUSE or protocol/server) STACK_WIND returns or when the callback completes. Thus, you can usually ensure their continued existence by doing a dict_ref (or data_ref if you really only care about a single value). IIRC, DHT already does this for some layout xattrs that it aggregates across subvolumes. In most cases, though, Avati is correct: good practice would be to make a copy.
