Re: [patch 6/8] fuse: clean up setting i_size in write

From: Andrew Morton
Date: Tue Mar 18 2008 - 01:09:20 EST


On Mon, 17 Mar 2008 20:19:14 +0100 Miklos Szeredi <miklos@xxxxxxxxxx> wrote:

> From: Miklos Szeredi <mszeredi@xxxxxxx>
>
> Extract common code for setting i_size in write functions into a
> common helper.
>
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
> ---
> fs/fuse/file.c | 28 +++++++++++++++-------------
> 1 file changed, 15 insertions(+), 13 deletions(-)
>
> Index: linux/fs/fuse/file.c
> ===================================================================
> --- linux.orig/fs/fuse/file.c 2008-03-17 18:26:04.000000000 +0100
> +++ linux/fs/fuse/file.c 2008-03-17 18:26:28.000000000 +0100
> @@ -610,13 +610,24 @@ static int fuse_write_begin(struct file
> return 0;
> }
>
> +static void fuse_write_update_size(struct inode *inode, loff_t pos)
> +{
> + struct fuse_conn *fc = get_fuse_conn(inode);
> + struct fuse_inode *fi = get_fuse_inode(inode);
> +
> + spin_lock(&fc->lock);
> + fi->attr_version = ++fc->attr_version;
> + if (pos > inode->i_size)
> + i_size_write(inode, pos);
> + spin_unlock(&fc->lock);
> +}
>
> ...
>
> @@ -766,12 +772,8 @@ static ssize_t fuse_direct_io(struct fil
> }
> fuse_put_request(fc, req);
> if (res > 0) {
> - if (write) {
> - spin_lock(&fc->lock);
> - if (pos > inode->i_size)
> - i_size_write(inode, pos);
> - spin_unlock(&fc->lock);
> - }
> + if (write)
> + fuse_write_update_size(inode, pos);

We require that i_mutex be held here, to prevent i_size_write() deadlocks.
Is it held?

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