On Thu, Apr 12, 2018 at 6:08 PM, Miklos Szeredi <mszeredi@xxxxxxxxxx> wrote:
> Implement stacked reading.
>
I couldn't decipher the meaning of "readd" in the subject of this
and other file ops pacthes??
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> ---
> fs/overlayfs/file.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 56 insertions(+)
>
> diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
> index 409b542ff30c..a19429c5965d 100644
> --- a/fs/overlayfs/file.c
> +++ b/fs/overlayfs/file.c
> @@ -9,6 +9,7 @@
> #include <linux/cred.h>
> #include <linux/file.h>
> #include <linux/xattr.h>
> +#include <linux/uio.h>
> #include "overlayfs.h"
>
> static struct file *ovl_open_realfile(const struct file *file)
> @@ -129,8 +130,63 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
> i_size_read(realinode));
> }
>
> +static void ovl_file_accessed(struct file *file)
> +{
> + struct inode *inode = file_inode(file);
> +
> + if ((file->f_flags & O_NOATIME) || !ovl_inode_upper(inode))
> + return;
> +
> + ovl_copytimes(inode);
> + touch_atime(&file->f_path);
> +}
> +
> +static rwf_t ovl_iocb_to_rwf(struct kiocb *iocb)
> +{
> + int ifl = iocb->ki_flags;
> + rwf_t flags = 0;
> +
> + if (ifl & IOCB_NOWAIT)
> + flags |= RWF_NOWAIT;
> + if (ifl & IOCB_HIPRI)
> + flags |= RWF_HIPRI;
> + if (ifl & IOCB_DSYNC)
> + flags |= RWF_DSYNC;
> + if (ifl & IOCB_SYNC)
> + flags |= RWF_SYNC;
> +
> + return flags;
> +}
> +
> +static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
> +{
> + struct file *file = iocb->ki_filp;
> + struct fd real;
> + const struct cred *old_cred;
> + ssize_t ret;
> +
> + if (!iov_iter_count(iter))
> + return 0;
> +
> + ret = ovl_real_file(file, &real);
> + if (ret)
> + return ret;
> +
> + old_cred = ovl_override_creds(file_inode(file)->i_sb);
> + ret = vfs_iter_read(real.file, iter, &iocb->ki_pos,
> + ovl_iocb_to_rwf(iocb));
> + revert_creds(old_cred);
> +
> + ovl_file_accessed(file);
> +
> + fdput(real);
I find it confusing that the name of ovl_real_file() does not suggest it
may take a reference, so this fdput() looks unbalanced.
All other ovl_XXX_{real,upper,lower} helpers do not take a reference.
Perhaps something along the lines of ovl_file_real_fdget().
Thanks,
Amir.
