Hi Xin, On Thu 29-03-07 10:41:01, Xin Zhao wrote: > I know we can use device inode's radix tree to achieve the same goal. > The only downside could be: First, by default, Linux will not add the > data pages into that radix tree. Only when a file is opened in Right. > O_DIRECT, the data pages will be put into dev's radix tree. Moreover, If you use O_DIRECT, I don't think the data will and in any radix tree - ideally they go directly to disk in this case. > if the partition is big, I am not sure whether the lookup overhead is > an issue. So it might need some optimization. Maybe, but I'd not say so as my first guess. > Can you elaborate more about the aliasing issues mentioned in your > email? I do have some mechanisms to handle the following situation: > suppose two files share same data blocks. Now two processes open the > two files separately. If one process writes a file, the other file > will be affected. Is this the aliasing issue you referred to? Yes, this is exactly what I meant. Note that these problems are not only about writes but also about truncate and such... Honza -- Jan Kara <jack@xxxxxxx> SuSE CR Labs - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
