On Thu, Nov 2, 2017 at 2:28 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > On Wed, Nov 01, 2017 at 10:22:47PM +0200, Amir Goldstein wrote: >> From: Chandan Rajendra <chandan@xxxxxxxxxxxxxxxxxx> >> >> Generate unique values of st_dev per lower layer for non-samefs >> overlay mount. The unique values are obtained by allocating anonymous >> bdevs for each of the lowerdirs in the overlayfs instance. > > Still not sure that why are we allocating anonymous bdev only for > lower and not upper. Until and unless we have a good reason not not > do so, treating them in same way will make it atleast easier to > understand? > I too find it hard to understand and to explain why anonymous bdev are needed. But I really don't see how allocating anonymous bdev for upper makes it easier to understand... If you think that it makes the code easier to understand, please show me where, because I don't see it. Both in ovl_getattr() and in ovl_lookup(), lower and upper are handled with completely different code anyway and upper dentry is stored differently (in overlay inode) than lower dentry (in overlay dentry). Anyway, as I wrote, I don't remember if there was a concrete reason why *not* to allocate anon bdev for upper, or simply that there was no good reason to *yes* allocate anon bdev to upper, so need to refer this question to Miklos who suggested this solution: https://marc.info/?l=linux-unionfs&m=149259338809700&w=2 Amir. -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
