Re: [PATCH 072/104] virtiofsd: passthrough_ll: fix refcounting on remove/rename

[Misono Tomohiro]

> From: Miklos Szeredi <address@hidden>
> 
> Signed-off-by: Miklos Szeredi <address@hidden>

I'm not familiar with qemu convention but shouldn't we put
at least one line of description like linux kernel?

For code itself:
 Reviewed-by: Misono Tomohiro <address@hidden>

> ---
>  tools/virtiofsd/passthrough_ll.c | 50 +++++++++++++++++++++++++++++++-
>  1 file changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/virtiofsd/passthrough_ll.c 
> b/tools/virtiofsd/passthrough_ll.c
> index 0f33c3c5e9..1b84d4f313 100644
> --- a/tools/virtiofsd/passthrough_ll.c
> +++ b/tools/virtiofsd/passthrough_ll.c
> @@ -1077,17 +1077,42 @@ out_err:
>      fuse_reply_err(req, saverr);
>  }
>  
> +static struct lo_inode *lookup_name(fuse_req_t req, fuse_ino_t parent,
> +                                    const char *name)
> +{
> +    int res;
> +    struct stat attr;
> +
> +    res = fstatat(lo_fd(req, parent), name, &attr,
> +                  AT_EMPTY_PATH | AT_SYMLINK_NOFOLLOW);
> +    if (res == -1) {
> +        return NULL;
> +    }
> +
> +    return lo_find(lo_data(req), &attr);
> +}
> +
>  static void lo_rmdir(fuse_req_t req, fuse_ino_t parent, const char *name)
>  {
>      int res;
> +    struct lo_inode *inode;
> +    struct lo_data *lo = lo_data(req);
> +
>      if (!is_safe_path_component(name)) {
>          fuse_reply_err(req, EINVAL);
>          return;
>      }
>  
> +    inode = lookup_name(req, parent, name);
> +    if (!inode) {
> +        fuse_reply_err(req, EIO);
> +        return;
> +    }
> +
>      res = unlinkat(lo_fd(req, parent), name, AT_REMOVEDIR);
>  
>      fuse_reply_err(req, res == -1 ? errno : 0);
> +    unref_inode_lolocked(lo, inode, 1);
>  }
>  
>  static void lo_rename(fuse_req_t req, fuse_ino_t parent, const char *name,
> @@ -1095,12 +1120,23 @@ static void lo_rename(fuse_req_t req, fuse_ino_t 
> parent, const char *name,
>                        unsigned int flags)
>  {
>      int res;
> +    struct lo_inode *oldinode;
> +    struct lo_inode *newinode;
> +    struct lo_data *lo = lo_data(req);
>  
>      if (!is_safe_path_component(name) || !is_safe_path_component(newname)) {
>          fuse_reply_err(req, EINVAL);
>          return;
>      }
>  
> +    oldinode = lookup_name(req, parent, name);
> +    newinode = lookup_name(req, newparent, newname);
> +
> +    if (!oldinode) {
> +        fuse_reply_err(req, EIO);
> +        goto out;
> +    }
> +
>      if (flags) {
>  #ifndef SYS_renameat2
>          fuse_reply_err(req, EINVAL);
> @@ -1113,26 +1149,38 @@ static void lo_rename(fuse_req_t req, fuse_ino_t 
> parent, const char *name,
>              fuse_reply_err(req, res == -1 ? errno : 0);
>          }
>  #endif
> -        return;
> +        goto out;
>      }
>  
>      res = renameat(lo_fd(req, parent), name, lo_fd(req, newparent), newname);
>  
>      fuse_reply_err(req, res == -1 ? errno : 0);
> +out:
> +    unref_inode_lolocked(lo, oldinode, 1);
> +    unref_inode_lolocked(lo, newinode, 1);
>  }
>  
>  static void lo_unlink(fuse_req_t req, fuse_ino_t parent, const char *name)
>  {
>      int res;
> +    struct lo_inode *inode;
> +    struct lo_data *lo = lo_data(req);
>  
>      if (!is_safe_path_component(name)) {
>          fuse_reply_err(req, EINVAL);
>          return;
>      }
>  
> +    inode = lookup_name(req, parent, name);
> +    if (!inode) {
> +        fuse_reply_err(req, EIO);
> +        return;
> +    }
> +
>      res = unlinkat(lo_fd(req, parent), name, 0);
>  
>      fuse_reply_err(req, res == -1 ? errno : 0);
> +    unref_inode_lolocked(lo, inode, 1);
>  }
>  
>  static void unref_inode_lolocked(struct lo_data *lo, struct lo_inode *inode,
> -- 
> 2.23.0