tree 6a68fdb6a0b6dfca8f1962ab327b85ea6cdbc14b
parent 2a9c6d066e98c1fe51a735b1439929f2f2afd891
author Chandan Rajendra <chandan@linux.vnet.ibm.com> 1500879474 -0500
committer Miklos Szeredi <mszeredi@redhat.com> 1510219407 +0100

ovl: return anonymous st_dev for lower inodes

For non-samefs setup, to make sure that st_dev/st_ino pair is unique
across the system, we return a unique anonymous st_dev for stat(2)
of lower layer inode.

A following patch is going to fix constant st_dev/st_ino across copy up
by returning origin st_dev/st_ino for copied up objects.

If the st_dev/st_ino for copied up object would have been the same as
that of the real underlying lower file, running diff on underlying lower
file and overlay copied up file would result in diff reporting that the
2 files are equal when in fact, they may have different content.

[amir: simplify ovl_get_pseudo_dev()
       split from allocate anonymous bdev patch]

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>