Re: [PATCH v2 07/28] fsnotify: add FSNOTIFY_EVENT_RENAME data type

[Amir Goldstein]

On Thu, Apr 16, 2026 at 7:35 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>
> Add a new fsnotify_rename_data struct and FSNOTIFY_EVENT_RENAME data
> type that carries both the moved dentry and the inode that was
> overwritten by the rename (if any).
>
> Update fsnotify_data_inode(), fsnotify_data_dentry(), and
> fsnotify_data_sb() to handle the new type, and add a new
> fsnotify_data_rename_target() helper for extracting the overwritten
> target inode.
>
> Update fsnotify_move() to use the new data type for FS_RENAME and
> FS_MOVED_TO events, passing the overwritten target inode through the
> event data. FS_MOVED_FROM is unchanged since the source directory
> doesn't need overwrite information.
>
> This is done so that fsnotify consumers like nfsd can atomically
> observe the overwritten file when a rename replaces an existing entry,
> without needing a separate FS_DELETE event.
>
> Assisted-by: Claude (Anthropic Claude Code)
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
>  include/linux/fsnotify.h         |  8 ++++++--
>  include/linux/fsnotify_backend.h | 20 ++++++++++++++++++++
>  2 files changed, 26 insertions(+), 2 deletions(-)

It is strange to me that the NFS protocol needs to report the overwritten
node in the same event of the rename, but oh well, fine by me.

Feel free to add:
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>

Thanks,
Amir.

>
> diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> index 079c18bcdbde..bda798bc67bc 100644
> --- a/include/linux/fsnotify.h
> +++ b/include/linux/fsnotify.h
> @@ -257,6 +257,10 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
>         __u32 new_dir_mask = FS_MOVED_TO;
>         __u32 rename_mask = FS_RENAME;
>         const struct qstr *new_name = &moved->d_name;
> +       struct fsnotify_rename_data rd = {
> +               .moved = moved,
> +               .target = target,
> +       };
>
>         if (isdir) {
>                 old_dir_mask |= FS_ISDIR;
> @@ -265,12 +269,12 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
>         }
>
>         /* Event with information about both old and new parent+name */
> -       fsnotify_name(rename_mask, moved, FSNOTIFY_EVENT_DENTRY,
> +       fsnotify_name(rename_mask, &rd, FSNOTIFY_EVENT_RENAME,
>                       old_dir, old_name, 0);
>
>         fsnotify_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE,
>                       old_dir, old_name, fs_cookie);
> -       fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE,
> +       fsnotify_name(new_dir_mask, &rd, FSNOTIFY_EVENT_RENAME,
>                       new_dir, new_name, fs_cookie);
>
>         if (target)
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index 66e185bd1b1b..f8c8fb7f34ae 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -311,6 +311,7 @@ enum fsnotify_data_type {
>         FSNOTIFY_EVENT_DENTRY,
>         FSNOTIFY_EVENT_MNT,
>         FSNOTIFY_EVENT_ERROR,
> +       FSNOTIFY_EVENT_RENAME,
>  };
>
>  struct fs_error_report {
> @@ -335,6 +336,11 @@ struct fsnotify_mnt {
>         u64 mnt_id;
>  };
>
> +struct fsnotify_rename_data {
> +       struct dentry *moved;   /* the dentry that was renamed */
> +       struct inode *target;   /* inode overwritten by rename, or NULL */
> +};
> +
>  static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
>  {
>         switch (data_type) {
> @@ -348,6 +354,8 @@ static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
>                 return d_inode(file_range_path(data)->dentry);
>         case FSNOTIFY_EVENT_ERROR:
>                 return ((struct fs_error_report *)data)->inode;
> +       case FSNOTIFY_EVENT_RENAME:
> +               return d_inode(((const struct fsnotify_rename_data *)data)->moved);
>         default:
>                 return NULL;
>         }
> @@ -363,6 +371,8 @@ static inline struct dentry *fsnotify_data_dentry(const void *data, int data_typ
>                 return ((const struct path *)data)->dentry;
>         case FSNOTIFY_EVENT_FILE_RANGE:
>                 return file_range_path(data)->dentry;
> +       case FSNOTIFY_EVENT_RENAME:
> +               return ((struct fsnotify_rename_data *)data)->moved;
>         default:
>                 return NULL;
>         }
> @@ -395,6 +405,8 @@ static inline struct super_block *fsnotify_data_sb(const void *data,
>                 return file_range_path(data)->dentry->d_sb;
>         case FSNOTIFY_EVENT_ERROR:
>                 return ((struct fs_error_report *) data)->sb;
> +       case FSNOTIFY_EVENT_RENAME:
> +               return ((const struct fsnotify_rename_data *)data)->moved->d_sb;
>         default:
>                 return NULL;
>         }
> @@ -430,6 +442,14 @@ static inline struct fs_error_report *fsnotify_data_error_report(
>         }
>  }
>
> +static inline struct inode *fsnotify_data_rename_target(const void *data,
> +                                                       int data_type)
> +{
> +       if (data_type == FSNOTIFY_EVENT_RENAME)
> +               return ((const struct fsnotify_rename_data *)data)->target;
> +       return NULL;
> +}
> +
>  static inline const struct file_range *fsnotify_data_file_range(
>                                                         const void *data,
>                                                         int data_type)
>
> --
> 2.53.0
>