Hi Miao, I was following this thread in the past, but I did not understand it fully, maybe you can explain?
>> >> # mkfs.btrfs <partition> >> >> # mount <partition> <mnt> >> >> # cd <mnt> >> >> # for ((i=0;i<2400;i++)); do touch long_name_to_make_tree_more_deep$i; >> >> done >> >> # for ((i=0; i<4; i++)) >> >> > do >> >> > mkdir $i >> >> > for ((j=0; j<200; j++)) >> >> > do >> >> > btrfs sub snap . $i/$j >> >> > done & >> >> > done >> > >> > snapshot creation has a critical section. Once we copy a given root to >> > its snapshot, we're not allowed to change it until the transaction >> > is fully committed. Is the limitation that if we are creating a snap B of root A, and placing the root of B somewhere into the tree of A, then we can do this only once per transaction? Does this limitation still exist or your fix fixes it? Also, according to your reproducer, each "btrfs sub snap" will start/join a transaction, but then it will call btrfs_commit_transaction() and not btrfs_commit_transaction_async(), so it will wait until the transaction commits. So how it may happen that you create more than one snap in the same transaction with your reproducer? The reason I am asking, is that I want to try to write code that creates several snaps in one transaction and only then commits. Should this be possible or there is some limitation, like I mentioned above? Thanks for your help, Alex. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
