Hello, everyone. I have some questions about mds locks. I search google and read almost all Sage's papers, but I found no details about mds locks. :( 1, There are three classes about locks in mds: SimpleLock, ScatterLock and LocalLock which are used for different lock items such as CDentry.lock, CInode.authlock. What is the difference among the three classes? or which situation they are used for? 2, There are 13 kinds of locks defined in ceph_fs.h: CEPH_LOCK_DVERSION to CEPH_LOCK_IPOLICY, according to them there are 13 kinds of lock items,: two in CDentry and 11 in CInode. I think they are used to lock different zone of their parent (CDentry or CInode). Is that right? And which zone they locks? 2, Each lock item have 38 states which is defined in locks.h and organized by 4 state machines. Is there any documents described these states and state machines? Many states look the same, such as LOCK_LOCK and LOCK_EXCL, What is their difference? Or under what condition, the state changes? 3, Each lock item can get rdlocks, wrlocks, xlocks and maybe remote_wrlocks. It seems that the life cycle of rdlocks, wrlocks and xlocks is the same as a MDRequest, is that right? What is the difference between these kinds of locks and the states(LOCK_SYNC, LOCK_LOCK ,....)? I have read the codes about mds locks for almost one week, but I think I missed some key designs or ideas, so the codes is quite hard to understand for me. Thanks for any help. -- Dong Yuan Email:yuandong1222@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
