Re: [RFC PATCH 24/35] Revert "ovl: fix relatime for directories"

[Vivek Goyal <vgoyal@redhat.com>]

On Thu, Apr 12, 2018 at 05:08:15PM +0200, Miklos Szeredi wrote:
> This reverts commit cd91304e7190b4c4802f8e413ab2214b233e0260.
> 
> Overlayfs no longer relies on the vfs correct atime handling.
> 
> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
> ---
>  fs/inode.c             | 21 ++++-----------------
>  fs/overlayfs/super.c   |  3 ---
>  include/linux/dcache.h |  3 ---
>  3 files changed, 4 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/inode.c b/fs/inode.c
> index ef362364d396..163715de8cb2 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -1570,24 +1570,11 @@ EXPORT_SYMBOL(bmap);
>  static void update_ovl_inode_times(struct dentry *dentry, struct inode *inode,
>  			       bool rcu)
>  {
> -	struct dentry *upperdentry;
> +	if (!rcu) {
> +		struct inode *realinode = d_real_inode(dentry);
>  
> -	/*
> -	 * 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) ||
> +		if (unlikely(inode != realinode) &&
> +		    (!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;
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index c3d8c7ea180f..006dc70d7425 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -107,9 +107,6 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
>  	if (inode && d_inode(dentry) == inode)
>  		return dentry;
>  
> -	if (flags & D_REAL_UPPER)
> -		return ovl_dentry_upper(dentry);
> -
>  	if (!d_is_reg(dentry)) {
>  		if (!inode || inode == d_inode(dentry))
>  			return dentry;
> diff --git a/include/linux/dcache.h b/include/linux/dcache.h
> index 82a99d366aec..4c7ab11c627a 100644
> --- a/include/linux/dcache.h
> +++ b/include/linux/dcache.h
> @@ -565,9 +565,6 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper)
>  	return upper;
>  }
>  
> -/* d_real() flags */
> -#define D_REAL_UPPER	0x2	/* return upper dentry or NULL if non-upper */

Good to see this go away. It was a major headache for metacopy only
patches. 

Vivek
> -
>  /**
>   * d_real - Return the real dentry
>   * @dentry: the dentry to query
> -- 
> 2.14.3
> 
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