On Thu, Apr 26, 2018 at 12:09 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> Right now ovl_inode stores inode pointer for lower inode. This helps
> with quickly getting lower inode given overlay inode (ovl_inode_lower()).
>
> Now with metadata only copy-up, we can have metacopy inode in middle
> layer as well and inode containing data can be different from ->lower.
> I need to be able to open the real file in ovl_open_realfile() and
> for that I need to quickly find the lower data inode.
>
> Hence store lower data inode also in ovl_inode. Also provide an
> helper ovl_inode_lowerdata() to access this field.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> ---
> fs/overlayfs/export.c | 3 ++-
> fs/overlayfs/inode.c | 5 +++--
> fs/overlayfs/namei.c | 5 ++++-
> fs/overlayfs/overlayfs.h | 6 ++++--
> fs/overlayfs/ovl_entry.h | 1 +
> fs/overlayfs/super.c | 4 +++-
> fs/overlayfs/util.c | 10 +++++++++-
> 7 files changed, 26 insertions(+), 8 deletions(-)
>
> diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
> index e1f6546b6c84..d43d926ae68e 100644
> --- a/fs/overlayfs/export.c
> +++ b/fs/overlayfs/export.c
> @@ -305,7 +305,8 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
> if (d_is_dir(upper ?: lower))
> return ERR_PTR(-EIO);
>
> - inode = ovl_get_inode(sb, dget(upper), lowerpath, index, !!lower, NULL);
> + inode = ovl_get_inode(sb, dget(upper), lowerpath, index, !!lower, NULL,
> + NULL);
> if (IS_ERR(inode)) {
> dput(upper);
> return ERR_CAST(inode);
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index 9d17f15480de..a6cd57741a1f 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -802,7 +802,8 @@ static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper,
>
> struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
> struct ovl_path *lowerpath, struct dentry *index,
> - unsigned int numlower, char *redirect)
> + unsigned int numlower, char *redirect,
> + struct dentry *lowerdata)
> {
> struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL;
> struct inode *inode;
> @@ -861,7 +862,7 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
> }
> }
> ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino, fsid);
> - ovl_inode_init(inode, upperdentry, lowerdentry);
> + ovl_inode_init(inode, upperdentry, lowerdentry, lowerdata);
>
> if (upperdentry && ovl_is_impuredir(upperdentry))
> ovl_set_flag(OVL_IMPURE, inode);
> diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
> index 682f0d402986..b25e32cf5916 100644
> --- a/fs/overlayfs/namei.c
> +++ b/fs/overlayfs/namei.c
> @@ -1070,8 +1070,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
> upperdentry = dget(index);
>
> if (upperdentry || ctr) {
> + struct dentry *lowerdata = NULL;
> + if (ctr > 1 && !d.is_dir)
> + lowerdata = stack[ctr - 1].dentry;
> inode = ovl_get_inode(dentry->d_sb, upperdentry, stack, index,
> - ctr, upperredirect);
> + ctr, upperredirect, lowerdata);
> err = PTR_ERR(inode);
> if (IS_ERR(inode))
> goto out_free_oe;
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index 29b28ee50b0f..29c3498a7e61 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -234,6 +234,7 @@ struct dentry *ovl_dentry_real_data(struct dentry *dentry);
> struct dentry *ovl_i_dentry_upper(struct inode *inode);
> struct inode *ovl_inode_upper(struct inode *inode);
> struct inode *ovl_inode_lower(struct inode *inode);
> +struct inode *ovl_inode_lowerdata(struct inode *inode);
> struct inode *ovl_inode_real(struct inode *inode);
> struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
> void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
> @@ -253,7 +254,7 @@ bool ovl_redirect_dir(struct super_block *sb);
> const char *ovl_dentry_get_redirect(struct dentry *dentry);
> void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
> void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
> - struct dentry *lowerdentry);
> + struct dentry *lowerdentry, struct dentry *lowerdata);
> void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
> void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
> u64 ovl_dentry_version_get(struct dentry *dentry);
> @@ -373,7 +374,8 @@ struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
> bool is_upper);
> struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
> struct ovl_path *lowerpath, struct dentry *index,
> - unsigned int numlower, char *redirect);
> + unsigned int numlower, char *redirect,
> + struct dentry *lowerdata);
I don't like the fact that the argument list keeps on growing.
It might be the right time to add an "inode context" or extend struct
ovl_lookup_data to include also all or many of the arguments passed
into ovl_get_inode().
You don't have to to that if you don't want to...
> static inline void ovl_copyattr(struct inode *from, struct inode *to)
> {
> to->i_uid = from->i_uid;
> diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
> index da65118a0567..83e031e31ff9 100644
> --- a/fs/overlayfs/ovl_entry.h
> +++ b/fs/overlayfs/ovl_entry.h
> @@ -97,6 +97,7 @@ struct ovl_inode {
> struct inode vfs_inode;
> struct dentry *__upperdentry;
> struct inode *lower;
> + struct inode *lowerdata;
Please union this field with struct ovl_dir_cache *cache,
but need to be careful when freeing.
Thanks,
Amir.
--
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
