On Wed, Jan 31, 2018 at 11:13 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> So far lower could not be a meta inode. So whenever it was time to copy
> up data of a meta inode, we could copy it up from top most lower dentry.
>
> But now lower itself can be a metacopy inode. That means data copy up
> needs to take place from a data inode in metacopy inode chain. Find
> lower data inode in the chain and use that for data copy up.
>
> Introduced a helper called ovl_path_lowerdata() to find the lower
> data inode chain.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/overlayfs/copy_up.c | 14 ++++++++++----
> fs/overlayfs/overlayfs.h | 1 +
> fs/overlayfs/util.c | 14 ++++++++++++++
> 3 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
> index 0bfc1df13b79..f4ece4754725 100644
> --- a/fs/overlayfs/copy_up.c
> +++ b/fs/overlayfs/copy_up.c
> @@ -489,13 +489,15 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
> }
>
> if (S_ISREG(c->stat.mode) && !c->metacopy) {
> - struct path upperpath;
> + struct path upperpath, datapath;
>
> ovl_path_upper(c->dentry, &upperpath);
> BUG_ON(upperpath.dentry != NULL);
> upperpath.dentry = temp;
>
> - err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size);
> + ovl_path_lowerdata(c->dentry, &datapath);
> + BUG_ON(datapath.dentry == NULL);
> + err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
> if (err)
> return err;
> }
> @@ -627,14 +629,18 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
> /* Copy up data of an inode which was copied up metadata only in the past. */
> static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
> {
> - struct path upperpath;
> + struct path upperpath, datapath;
> int err;
>
> ovl_path_upper(c->dentry, &upperpath);
> if (WARN_ON(upperpath.dentry == NULL))
> return -EIO;
>
> - err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size);
> + ovl_path_lowerdata(c->dentry, &datapath);
> + if (WARN_ON(datapath.dentry == NULL))
> + return -EIO;
> +
> + err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
> if (err)
> return err;
>
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index de400606df0c..9ec65f0b5384 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -210,6 +210,7 @@ bool ovl_dentry_weird(struct dentry *dentry);
> enum ovl_path_type ovl_path_type(struct dentry *dentry);
> void ovl_path_upper(struct dentry *dentry, struct path *path);
> void ovl_path_lower(struct dentry *dentry, struct path *path);
> +void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
> enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
> struct dentry *ovl_dentry_upper(struct dentry *dentry);
> struct dentry *ovl_dentry_lower(struct dentry *dentry);
> diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
> index e717d561019d..73c055ed34cd 100644
> --- a/fs/overlayfs/util.c
> +++ b/fs/overlayfs/util.c
> @@ -132,6 +132,20 @@ void ovl_path_lower(struct dentry *dentry, struct path *path)
> }
> }
>
> +void ovl_path_lowerdata(struct dentry *dentry, struct path *path)
> +{
> + struct ovl_entry *oe = dentry->d_fsdata;
> + int idx = oe->numlower - 1;
> +
> + if (!oe->numlower) {
> + *path = (struct path) { };
> + return;
> + }
> +
> + path->mnt = oe->lowerstack[idx].layer->mnt;
> + path->dentry = oe->lowerstack[idx].dentry;
> +}
> +
> enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
> {
> enum ovl_path_type type = ovl_path_type(dentry);
> --
> 2.13.6
>
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