Re: [PATCH v3 1/4] fs: add generic helper for filling statx attribute flags

Re: [PATCH v3 1/4] fs: add generic helper for filling statx attribute flags

[Amir Goldstein]

Forgot to CC linux-fsdevel and vfs/orangefs maintainers

On Sat, Jun 19, 2021 at 12:26 PM Amir Goldstein <amir73il@gmail.com> wrote:
>
> The immutable and append-only properties on an inode are published on
> the inode's i_flags and enforced by the VFS.
>
> Create a helper to fill the corresponding STATX_ATTR_ flags in the kstat
> structure from the inode's i_flags.
>
> Only orange was converted to use this helper.
> Other filesystems could use it in the future.
>
> Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>  fs/orangefs/inode.c  |  7 +------
>  fs/stat.c            | 18 ++++++++++++++++++
>  include/linux/fs.h   |  1 +
>  include/linux/stat.h |  4 ++++
>  4 files changed, 24 insertions(+), 6 deletions(-)
>
> diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
> index 6bf35a0d61f3..4092009716a3 100644
> --- a/fs/orangefs/inode.c
> +++ b/fs/orangefs/inode.c
> @@ -883,12 +883,7 @@ int orangefs_getattr(struct user_namespace *mnt_userns, const struct path *path,
>                 if (!(request_mask & STATX_SIZE))
>                         stat->result_mask &= ~STATX_SIZE;
>
> -               stat->attributes_mask = STATX_ATTR_IMMUTABLE |
> -                   STATX_ATTR_APPEND;
> -               if (inode->i_flags & S_IMMUTABLE)
> -                       stat->attributes |= STATX_ATTR_IMMUTABLE;
> -               if (inode->i_flags & S_APPEND)
> -                       stat->attributes |= STATX_ATTR_APPEND;
> +               generic_fill_statx_attr(inode, stat);
>         }
>         return ret;
>  }
> diff --git a/fs/stat.c b/fs/stat.c
> index 1fa38bdec1a6..314269150b5b 100644
> --- a/fs/stat.c
> +++ b/fs/stat.c
> @@ -59,6 +59,24 @@ void generic_fillattr(struct user_namespace *mnt_userns, struct inode *inode,
>  }
>  EXPORT_SYMBOL(generic_fillattr);
>
> +/**
> + * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
> + * @inode:     Inode to use as the source
> + * @stat:      Where to fill in the attribute flags
> + *
> + * Fill in the STATX_ATTR_ flags in the kstat structure for properties of the
> + * inode that are published on i_flags and enforced by the VFS.
> + */
> +void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
> +{
> +       if (inode->i_flags & S_IMMUTABLE)
> +               stat->attributes |= STATX_ATTR_IMMUTABLE;
> +       if (inode->i_flags & S_APPEND)
> +               stat->attributes |= STATX_ATTR_APPEND;
> +       stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
> +}
> +EXPORT_SYMBOL(generic_fill_statx_attr);
> +
>  /**
>   * vfs_getattr_nosec - getattr without security checks
>   * @path: file to get attributes from
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index c3c88fdb9b2a..647664316013 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3353,6 +3353,7 @@ extern int page_symlink(struct inode *inode, const char *symname, int len);
>  extern const struct inode_operations page_symlink_inode_operations;
>  extern void kfree_link(void *);
>  void generic_fillattr(struct user_namespace *, struct inode *, struct kstat *);
> +void generic_fill_statx_attr(struct inode *inode, struct kstat *stat);
>  extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
>  extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
>  void __inode_add_bytes(struct inode *inode, loff_t bytes);
> diff --git a/include/linux/stat.h b/include/linux/stat.h
> index fff27e603814..7df06931f25d 100644
> --- a/include/linux/stat.h
> +++ b/include/linux/stat.h
> @@ -34,6 +34,10 @@ struct kstat {
>          STATX_ATTR_ENCRYPTED |                         \
>          STATX_ATTR_VERITY                              \
>          )/* Attrs corresponding to FS_*_FL flags */
> +#define KSTAT_ATTR_VFS_FLAGS                           \
> +       (STATX_ATTR_IMMUTABLE |                         \
> +        STATX_ATTR_APPEND                              \
> +        ) /* Attrs corresponding to S_* flags that are enforced by the VFS */
>         u64             ino;
>         dev_t           dev;
>         dev_t           rdev;
> --
> 2.32.0
>