On Tue, May 15, 2018 at 12:26 PM, Amir Goldstein <amir73il@xxxxxxxxx> wrote:
> Al Viro suggested to simplify callers of ovl_create_real() by
> returning the created dentry (or ERR_PTR) from ovl_create_real().
> This is a spin off of his suggestion, which is cleaner in my opinion.
>
> Also created a wrapper ovl_create_temp_dir() and used it in
> ovl_create_index() instead of calling ovl_do_mkdir(), so now all callers
> of ovl_do_mkdir() are routed through ovl_create_real(), which paves the
> way for Al's fix for non-hashed result from vfs_mkdir().
>
> Suggested-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/overlayfs/copy_up.c | 27 +++++++--------------------
> fs/overlayfs/dir.c | 47 +++++++++++++++++++++++++++++------------------
> fs/overlayfs/overlayfs.h | 9 ++++++++-
> 3 files changed, 44 insertions(+), 39 deletions(-)
>
> diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
> index 8bede0742619..4ba16cbeaec2 100644
> --- a/fs/overlayfs/copy_up.c
> +++ b/fs/overlayfs/copy_up.c
> @@ -365,14 +365,10 @@ static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
> if (err)
> return err;
>
> - temp = ovl_lookup_temp(indexdir);
> + temp = ovl_create_temp_dir(indexdir);
#define OVL_DIR_CATTR(m) (&(struct cattr) { .mode = S_IFDIR | (m) })
temp = ovl_create_temp(indexdir, OVL_DIR_CATTR(0), NULL);
> if (IS_ERR(temp))
> goto temp_err;
>
> - err = ovl_do_mkdir(dir, temp, S_IFDIR, true);
> - if (err)
> - goto out;
> -
> err = ovl_set_upper_fh(upper, temp);
> if (err)
> goto out_cleanup;
> @@ -501,22 +497,13 @@ static int ovl_get_tmpfile(struct ovl_copy_up_ctx *c, struct dentry **tempp)
> if (new_creds)
> old_creds = override_creds(new_creds);
>
> - if (c->tmpfile) {
> + if (c->tmpfile)
> temp = ovl_do_tmpfile(c->workdir, c->stat.mode);
> - if (IS_ERR(temp))
> - goto temp_err;
> - } else {
> - temp = ovl_lookup_temp(c->workdir);
> - if (IS_ERR(temp))
> - goto temp_err;
> -
> - err = ovl_create_real(d_inode(c->workdir), temp, &cattr,
> - NULL, true);
> - if (err) {
> - dput(temp);
> - goto out;
> - }
> - }
> + else
> + temp = ovl_create_temp(c->workdir, &cattr, NULL);
> + if (IS_ERR(temp))
> + goto temp_err;
> +
> err = 0;
> *tempp = temp;
> out:
> diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
> index 25b339278684..45f5f9232e71 100644
> --- a/fs/overlayfs/dir.c
> +++ b/fs/overlayfs/dir.c
> @@ -160,6 +160,26 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
> return err;
> }
>
> +struct dentry *ovl_create_temp(struct dentry *workdir, struct cattr *attr,
> + struct dentry *hardlink)
Talking of cleanups, can we put hardlink into cattr as well? (separate patch)
> +{
> + struct inode *wdir = workdir->d_inode;
> + struct dentry *temp;
> + int err;
> +
> + temp = ovl_lookup_temp(workdir);
> + if (IS_ERR(temp))
> + return temp;
What's wrong with viro's version of dentry in ovl_create_real()?
Turns this whole function into:
return ovl_create_real(d_inode(workdir),
ovl_lookup_temp(workdir), attr, hardlink, true);
> +
> + err = ovl_create_real(wdir, temp, attr, hardlink, true);
> + if (err) {
> + dput(temp);
> + return ERR_PTR(err);
> + }
> +
> + return temp;
> +}
> +
> static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
> int xerr)
> {
> @@ -292,15 +312,11 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
> if (upper->d_parent->d_inode != udir)
> goto out_unlock;
>
> - opaquedir = ovl_lookup_temp(workdir);
> + opaquedir = ovl_create_temp_dir(workdir);
Where has the mode gone?
> err = PTR_ERR(opaquedir);
> if (IS_ERR(opaquedir))
> - goto out_unlock;
> -
> - err = ovl_create_real(wdir, opaquedir,
> - &(struct cattr){.mode = stat.mode}, NULL, true);
> if (err)
> - goto out_dput;
> + goto out_unlock;
>
> err = ovl_copy_xattr(upper, opaquedir);
> if (err)
> @@ -331,7 +347,6 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
>
> out_cleanup:
> ovl_cleanup(wdir, opaquedir);
> -out_dput:
> dput(opaquedir);
> out_unlock:
> unlock_rename(workdir, upperdir);
> @@ -392,20 +407,16 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
> if (err)
> goto out;
>
> - newdentry = ovl_lookup_temp(workdir);
> - err = PTR_ERR(newdentry);
> - if (IS_ERR(newdentry))
> - goto out_unlock;
> -
> upper = lookup_one_len(dentry->d_name.name, upperdir,
> dentry->d_name.len);
> err = PTR_ERR(upper);
> if (IS_ERR(upper))
> - goto out_dput;
> + goto out_unlock;
>
> - err = ovl_create_real(wdir, newdentry, cattr, hardlink, true);
> - if (err)
> - goto out_dput2;
> + newdentry = ovl_create_temp(workdir, cattr, hardlink);
> + err = PTR_ERR(newdentry);
> + if (IS_ERR(newdentry))
> + goto out_dput;
>
> /*
> * mode could have been mutilated due to umask (e.g. sgid directory)
> @@ -454,9 +465,9 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
> err = ovl_instantiate(dentry, inode, newdentry, !!hardlink);
> newdentry = NULL;
> out_dput2:
> - dput(upper);
> -out_dput:
> dput(newdentry);
> +out_dput:
> + dput(upper);
> out_unlock:
> unlock_rename(workdir, upperdir);
> out:
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index 642b25702092..967183175ef5 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -369,6 +369,7 @@ static inline void ovl_copyflags(struct inode *from, struct inode *to)
>
> /* dir.c */
> extern const struct inode_operations ovl_dir_inode_operations;
> +int ovl_cleanup(struct inode *dir, struct dentry *dentry);
> struct dentry *ovl_lookup_temp(struct dentry *workdir);
> int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
> struct dentry *dentry);
> @@ -380,7 +381,13 @@ struct cattr {
> int ovl_create_real(struct inode *dir, struct dentry *newdentry,
> struct cattr *attr,
> struct dentry *hardlink, bool debug);
> -int ovl_cleanup(struct inode *dir, struct dentry *dentry);
> +struct dentry *ovl_create_temp(struct dentry *workdir, struct cattr *attr,
> + struct dentry *hardlink);
> +
> +static inline struct dentry *ovl_create_temp_dir(struct dentry *workdir)
> +{
> + return ovl_create_temp(workdir, &(struct cattr){.mode = S_IFDIR}, NULL);
> +}
>
> /* file.c */
> extern const struct file_operations ovl_file_operations;
> --
> 2.7.4
>
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