On Thu, Mar 29, 2018 at 10:38 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> Set redirect on metacopy files upon rename. This will help find data dentry
> in lower dirs.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> ---
> fs/overlayfs/dir.c | 50 +++++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 37 insertions(+), 13 deletions(-)
>
> diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
> index 3ea052b6bac7..7c0a02d9f6bd 100644
> --- a/fs/overlayfs/dir.c
> +++ b/fs/overlayfs/dir.c
> @@ -968,6 +968,27 @@ static void ovl_rename_unlock_ovl_inodes(struct dentry *old, struct dentry *new,
> mutex_unlock(&OVL_I(d_inode(new))->lock);
> }
>
> +static bool ovl_relative_redirect(struct dentry *dentry, bool samedir)
> +{
> + if (d_is_dir(dentry))
> + return samedir;
> +
> + /*
> + * For non-dir hardlinked files, we need absolute redirects
> + * in general as two upper hardlinks could be in different
> + * dirs. We could put a relative redirect now and convert
> + * it to absolute redirect later. But when nlink > 1 and
> + * indexing is on, that means relative redirect needs to be
> + * converted to absolute during copy up of another lower
> + * hardllink as well.
> + *
> + * So without optimizing too much, just check if non-dir
> + * has nlink > 1 or not. If yes, set absolute redirect to
> + * begin with.
> + */
> + return (d_inode(dentry)->i_nlink > 1 ? false : samedir);
I don't think this is wrong, but I don't like relying on the overlay inode
nlink. I wonder if you should separate the case of indexed and
non-indexed inode.
> +}
> +
> static int ovl_rename(struct inode *olddir, struct dentry *old,
> struct inode *newdir, struct dentry *new,
> unsigned int flags)
> @@ -1131,22 +1152,25 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
> goto out_dput;
>
> err = 0;
> - if (is_dir) {
> - if (ovl_type_merge_or_lower(old))
> - err = ovl_set_redirect(old, samedir);
> - else if (!old_opaque && ovl_type_merge(new->d_parent))
> - err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
> - if (err)
> - goto out_dput;
> - }
> - if (!overwrite && new_is_dir) {
> + if (ovl_type_merge_or_lower(old))
> + err = ovl_set_redirect(old,
> + ovl_relative_redirect(old, samedir));
> + else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent))
> + err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
> +
> + if (err)
> + goto out_dput;
> +
> + if (!overwrite) {
> if (ovl_type_merge_or_lower(new))
> - err = ovl_set_redirect(new, samedir);
> - else if (!new_opaque && ovl_type_merge(old->d_parent))
> + err = ovl_set_redirect(new, ovl_relative_redirect(new,
> + samedir));
> + else if (new_is_dir && !new_opaque &&
> + ovl_type_merge(old->d_parent))
> err = ovl_set_opaque_xerr(new, newdentry, -EXDEV);
> - if (err)
> - goto out_dput;
> }
> + if (err)
> + goto out_dput;
>
> err = ovl_do_rename(old_upperdir->d_inode, olddentry,
> new_upperdir->d_inode, newdentry, flags);
> --
> 2.13.6
>
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