On Sun, Jan 15, 2017 at 2:57 PM, Amir Goldstein <amir73il@xxxxxxxxx> wrote:
> Factor out some common vfs bits from do_tmpfile()
> to be used by overlayfs for concurrent copy up.
I'm wondering whether the vfs helper should do everything except the
path lookup and the open: d_alloc(), ->tmpfile() and setting
I_LINKABLE. This will also aid in doing a ->tmpfile() for overlayfs.
Thanks,
Miklos
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/namei.c | 26 ++++++++++++++++----------
> include/linux/fs.h | 1 +
> 2 files changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/fs/namei.c b/fs/namei.c
> index ad74877..4cbaf54 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -3353,6 +3353,20 @@ static int do_last(struct nameidata *nd,
> return error;
> }
>
> +int vfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
> +{
> + int error;
> +
> + /* we want directory to be writable */
> + error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
> + if (error)
> + return error;
> + if (!dir->i_op->tmpfile)
> + return -EOPNOTSUPP;
> + return dir->i_op->tmpfile(dir, dentry, mode);
> +}
> +EXPORT_SYMBOL(vfs_tmpfile);
> +
> static int do_tmpfile(struct nameidata *nd, unsigned flags,
> const struct open_flags *op,
> struct file *file, int *opened)
> @@ -3368,14 +3382,6 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
> if (unlikely(error))
> goto out;
> dir = path.dentry->d_inode;
> - /* we want directory to be writable */
> - error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
> - if (error)
> - goto out2;
> - if (!dir->i_op->tmpfile) {
> - error = -EOPNOTSUPP;
> - goto out2;
> - }
> child = d_alloc(path.dentry, &name);
> if (unlikely(!child)) {
> error = -ENOMEM;
> @@ -3383,8 +3389,8 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
> }
> dput(path.dentry);
> path.dentry = child;
> - error = dir->i_op->tmpfile(dir, child, op->mode);
> - if (error)
> + error = vfs_tmpfile(dir, child, op->mode);
> + if (unlikely(error))
> goto out2;
> audit_inode(nd->name, child, 0);
> /* Don't check for other permissions, the inode was just created */
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 2ba0743..13f56f1 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1560,6 +1560,7 @@ extern int vfs_rmdir(struct inode *, struct dentry *);
> extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
> extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
> extern int vfs_whiteout(struct inode *, struct dentry *);
> +extern int vfs_tmpfile(struct inode *, struct dentry *, umode_t);
>
> /*
> * VFS file helper functions.
> --
> 2.7.4
>
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