On Fri 16-09-16 14:19:23, Miklos Szeredi wrote:
> From: Aihua Zhang <zhangaihua1@xxxxxxxxxx>
>
> When an event occurs direct it to the overlay inode instead of the real
> underlying inode.
>
> This will work even if the file was first on the lower layer and then
> copied up, while the watch is there. This is because the watch is on the
> overlay inode, which stays the same through the copy-up.
>
> For filesystems other than overlayfs this is a no-op, except for the
> performance impact of an extra pointer dereferece.
>
> Verified to work correctly with the inotify/fanotify tests in LTP.
>
> Signed-off-by: Aihua Zhang <zhangaihua1@xxxxxxxxxx>
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Eric Paris <eparis@xxxxxxxxxx>
> ---
> include/linux/fsnotify.h | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> index eed9e853a06f..b8bcc058e031 100644
> --- a/include/linux/fsnotify.h
> +++ b/include/linux/fsnotify.h
> @@ -29,7 +29,11 @@ static inline int fsnotify_parent(struct path *path, struct dentry *dentry, __u3
> static inline int fsnotify_perm(struct file *file, int mask)
> {
> struct path *path = &file->f_path;
> - struct inode *inode = file_inode(file);
> + /*
> + * Do not use file_inode() here or anywhere in this file to get the
> + * inode. That would break *notity on overlayfs.
> + */
> + struct inode *inode = path->dentry->d_inode;
So shouldn't we rather have d_backing_inode(path->dentry) here and
everywhere else?
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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