On Tue, Sep 5, 2017 at 10:55 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: [...] > Alternatively, update_ovl_inode_times() could use D_REAL_UPPER > and then we explicitly say that we don't care about lower mtime/ctime > modifications. Right, you convinced me that this is the right way to go. Updated patch below (and pushed to overlayfs-next). Thanks, Miklos --- From: Miklos Szeredi <mszeredi@xxxxxxxxxx> Subject: ovl: fix relatime for directories Need to treat non-regular overlayfs files the same as regular files when checking for an atime update. Add a d_real() flag to make it return the upper dentry for all file types. Reported-by: "zhangyi (F)" <yi.zhang@xxxxxxxxxx> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx> --- fs/inode.c | 21 +++++++++++++++++---- fs/overlayfs/super.c | 3 +++ include/linux/dcache.h | 3 +++ 3 files changed, 23 insertions(+), 4 deletions(-) --- a/fs/inode.c +++ b/fs/inode.c @@ -1569,11 +1569,24 @@ EXPORT_SYMBOL(bmap); static void update_ovl_inode_times(struct dentry *dentry, struct inode *inode, bool rcu) { - if (!rcu) { - struct inode *realinode = d_real_inode(dentry); + struct dentry *upperdentry; - if (unlikely(inode != realinode) && - (!timespec_equal(&inode->i_mtime, &realinode->i_mtime) || + /* + * Nothing to do if in rcu or if non-overlayfs + */ + if (rcu || likely(!(dentry->d_flags & DCACHE_OP_REAL))) + return; + + upperdentry = d_real(dentry, NULL, 0, D_REAL_UPPER); + + /* + * If file is on lower then we can't update atime, so no worries about + * stale mtime/ctime. + */ + if (upperdentry) { + struct inode *realinode = d_inode(upperdentry); + + if ((!timespec_equal(&inode->i_mtime, &realinode->i_mtime) || !timespec_equal(&inode->i_ctime, &realinode->i_ctime))) { inode->i_mtime = realinode->i_mtime; inode->i_ctime = realinode->i_ctime; --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -75,6 +75,9 @@ static struct dentry *ovl_d_real(struct struct dentry *real; int err; + if (flags & D_REAL_UPPER) + return ovl_dentry_upper(dentry); + if (!d_is_reg(dentry)) { if (!inode || inode == d_inode(dentry)) return dentry; --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -562,6 +562,9 @@ static inline struct dentry *d_backing_d return upper; } +/* d_real() flags */ +#define D_REAL_UPPER 0x2 /* return upper dentry or NULL if non-upper */ + /** * d_real - Return the real dentry * @dentry: the dentry to query -- 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