[PATCH v2 20/20] ovl: constant inode number for hardlinks

Amir Goldstein
2017-06-07T07:51:44Z

When inodes index feature is enabled, it is safe to return the copy up
origin st_ino for indexed upper hardlinks, because all indexed upper
hardlinks are represented by the same overlay inode as the copy up
origin.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
fs/overlayfs/inode.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 6e85a2a7fcdc..8a30dc6cd42d 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -96,11 +96,14 @@ int ovl_getattr(const struct path *path, struct kstat *stat,

WARN_ON_ONCE(stat->dev != lowerstat.dev);
/*
- * Lower hardlinks are broken on copy up to different
+ * Lower hardlinks may be broken on copy up to different
* upper files, so we cannot use the lower origin st_ino
* for those different files, even for the same fs case.
+ * Indexed upper inodes are safe and non-hardlinked
+ * origin inodes are safe.
*/
- if (is_dir || lowerstat.nlink == 1)
+ if (is_dir || lowerstat.nlink == 1 ||
+ OVL_TYPE_INDEX(type))
stat->ino = lowerstat.ino;
}
stat->dev = dentry->d_sb->s_dev;
--
2.7.4