On Tue, 02 Oct 2007 17:50:35 +0200
Miklos Szeredi <[EMAIL PROTECTED]> wrote:

> From: Miklos Szeredi <[EMAIL PROTECTED]>
> 
> Each WRITE request must carry a valid file descriptor.  When a page is
> written back from a memory mapping, the file through which the page
> was dirtied is not available, so a new mechananism is needed to find a
> suitable file in ->writepage(s).
> 
> A list of fuse_files is added to fuse_inode.  The file is removed from
> the list in fuse_release().
> 
> This patch is in preparation for writable mmap support.
> 
> Signed-off-by: Miklos Szeredi <[EMAIL PROTECTED]>
> ---
> 
> Index: linux/fs/fuse/file.c
> ===================================================================
> --- linux.orig/fs/fuse/file.c 2007-10-01 22:42:26.000000000 +0200
> +++ linux/fs/fuse/file.c      2007-10-01 22:42:27.000000000 +0200
> @@ -56,6 +56,7 @@ struct fuse_file *fuse_file_alloc(void)
>                       kfree(ff);
>                       ff = NULL;
>               }
> +             INIT_LIST_HEAD(&ff->write_entry);
>               atomic_set(&ff->count, 0);
>       }
>       return ff;
> @@ -150,12 +151,18 @@ int fuse_release_common(struct inode *in
>  {
>       struct fuse_file *ff = file->private_data;
>       if (ff) {
> +             struct fuse_conn *fc = get_fuse_conn(inode);
> +
>               fuse_release_fill(ff, get_node_id(inode), file->f_flags,
>                                 isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
>  
>               /* Hold vfsmount and dentry until release is finished */
>               ff->reserved_req->vfsmount = mntget(file->f_path.mnt);
>               ff->reserved_req->dentry = dget(file->f_path.dentry);
> +
> +             spin_lock(&fc->lock);
> +             list_del(&ff->write_entry);
> +             spin_unlock(&fc->lock);
>               /*
>                * Normally this will send the RELEASE request,
>                * however if some asynchronous READ or WRITE requests
> Index: linux/fs/fuse/fuse_i.h
> ===================================================================
> --- linux.orig/fs/fuse/fuse_i.h       2007-10-01 22:42:24.000000000 +0200
> +++ linux/fs/fuse/fuse_i.h    2007-10-01 22:43:15.000000000 +0200
> @@ -70,6 +70,9 @@ struct fuse_inode {
>  
>       /** Version of last attribute change */
>       u64 attr_version;
> +
> +     /** Files usable in writepage.  Protected by fc->lock */
> +     struct list_head write_files;
>  };
>  
>  /** FUSE specific file data */
> @@ -82,6 +85,9 @@ struct fuse_file {
>  
>       /** Refcount */
>       atomic_t count;
> +
> +     /** Entry on inode's write_files list */
> +     struct list_head write_entry;
>  };
>  
>  /** One input argument of a request */
> Index: linux/fs/fuse/inode.c
> ===================================================================
> --- linux.orig/fs/fuse/inode.c        2007-10-01 22:42:24.000000000 +0200
> +++ linux/fs/fuse/inode.c     2007-10-01 22:42:27.000000000 +0200
> @@ -56,6 +56,7 @@ static struct inode *fuse_alloc_inode(st
>       fi->i_time = 0;
>       fi->nodeid = 0;
>       fi->nlookup = 0;
> +     INIT_LIST_HEAD(&fi->write_files);
>       fi->forget_req = fuse_request_alloc();
>       if (!fi->forget_req) {
>               kmem_cache_free(fuse_inode_cachep, inode);
> @@ -68,6 +69,7 @@ static struct inode *fuse_alloc_inode(st
>  static void fuse_destroy_inode(struct inode *inode)
>  {
>       struct fuse_inode *fi = get_fuse_inode(inode);
> +     BUG_ON(!list_empty(&fi->write_files));
>       if (fi->forget_req)
>               fuse_request_free(fi->forget_req);
>       kmem_cache_free(fuse_inode_cachep, inode);

hm.  At no point in this patch series does anything actually get added to
these lists, so this patch is presently a no-op.

I'll assume that it will get used later.  But it is a bit odd to add
infrastructure in a patch series, then not use it.  Why not hold the patch
back and include it in the patch series which actually uses these lists for
something?


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