Hello, just a little review on the afr return "struct stat" scheme there are 18 functions[1] in xlator_fops which return a struct stat* in cbk. in 1.3.7 afr implement 16 of them(except fchmod and fchown, which return ENOSYS), and in TLA, all of them is implemented. most of them adopt a scheme to return a stable struct stat* when no child is out of work. It pick the successful returned value which is first appeared in the conf file. fstat and 1.3.7 readv is a little difference with others, these two functions do not send the op to all children, but only the first succesful child. So it's also stable. And in TLA, some funtion is changed to serial call (for example, mknod), and the returned struct stat is also come from the first succesful child, so it's also stable. but ftruncate, writev, lookup and TLA-version does not return a stable struct stat, ftruncate and writev pick the return value from the last successful returned child . and lookup pick the child with the largest mtime. the TLA-version readv return the struct stat from the rchild. Bug: when you use vim on a glusterfs file system (with afr and the children of afr direct to different machine). Sometimes you will get a warning: The file has been changed since reading it!!! I have submitted this bug at https://savannah.nongnu.org/bugs/?21945, but the patch provided by me only concern the writev and ftruncate functions, so it still can't fix this bug. I will provide a improved patch later. But is there a good excuse to let lookup return the stat with a largest mtime? And If you use read-volume option in afr, I suggest you putting the `read-volume' volume at the first place in the sub-volumes. Any suggestion? Thanks. [1] 1. lookup 2. stat 3. fstat 4. chmod 5. fchmod 6. chown 7. fchown 8. truncate 9. ftruncate 10. utimens 11. mknod 12. mkdir 13. symlink 14. rename 15. link 16. create 17. readv 18. writev -- Best Regards, LI Daobing
