ovl: update atime on upper
Fix atime update logic in overlayfs.
This patch adds an i_op->update_time() handler to overlayfs inodes. This
forwards atime updates to the upper layer only. No atime updates are done
on lower layers.
Remove implicit atime updates to underlying files and directories with
O_NOATIME. Remove explicit atime update in ovl_readlink().
Clear atime related mnt flags from cloned upper mount. This means atime
updates are controlled purely by overlayfs mount options.
Reported-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 8059891..058103c 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -608,7 +608,7 @@
struct file *ovl_path_open(struct path *path, int flags)
{
- return dentry_open(path, flags, current_cred());
+ return dentry_open(path, flags | O_NOATIME, current_cred());
}
static void ovl_put_super(struct super_block *sb)
@@ -1075,6 +1075,10 @@
pr_err("overlayfs: failed to clone upperpath\n");
goto out_put_lowerpath;
}
+ /* Don't inherit atime flags */
+ ufs->upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);
+
+ sb->s_time_gran = ufs->upper_mnt->mnt_sb->s_time_gran;
ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
err = PTR_ERR(ufs->workdir);
@@ -1122,7 +1126,7 @@
* Make lower_mnt R/O. That way fchmod/fchown on lower file
* will fail instead of modifying lower fs.
*/
- mnt->mnt_flags |= MNT_READONLY;
+ mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
ufs->lower_mnt[ufs->numlower] = mnt;
ufs->numlower++;