On Fri, Jun 2, 2017 at 8:32 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > On Thu, Jun 1, 2017 at 10:55 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: >> On Thu, Jun 1, 2017 at 11:02 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: >>> For the case of all layers not on the same fs, use the copy up >>> origin st_ino/st_dev for non-dir, if we know it. >>> >>> This guarantied constant and persistent st_ino/st_dev for non-dir, >>> but not system-wide uniqueness, like in the same fs case. >> >> I'd rather leave this until the st_dev uniqueness is sorted out. Non >> unique st_ino/st_dev is just asking for trouble. >> > > I don't mind leaving this out, but you do realize that this commit > doesn't change st_dev/st_ino uniqueness one way or the other, right? Depends on how you look at it. Before the patch it was (just the non-samefs, non-directory case): - if lower: st_ino/st_dev comes from lower - if upper: st_ino/st_dev comes from upper This only violates the uniqueness rule if check+use of st_ino/st_dev races with the copy up After the patch it's: - if copied up: st_ino/st_dev comes from origin - otherwise same as above Now the uniqueness is violated for all copied up files (origin and overlay file will have the same st_ino/st_dev pair even though they possibly have different contents). So that transforms a race into a permanent error, which is not good. Thanks, Miklos -- 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
