On Mon, Aug 16, 2021 at 8:39 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
>
> On Fri, Aug 13, 2021 at 05:31:55PM +0800, Xie Yongji wrote:
> > The invalidate_inode_pages2() might be called with FUSE_NOWRITE
> > set in fuse_finish_open(), which can lead to deadlock in
> > fuse_launder_page().
> >
> > To fix it, this tries to delay calling invalidate_inode_pages2()
> > until FUSE_NOWRITE is removed.
>
> Thanks for the report and the patch. I think it doesn't make sense to delay the
> invalidate_inode_pages2() call since the inode has been truncated in this case,
> there's no data worth writing out.
>
Right.
> This patch replaces the invalidate_inode_pages2() with a truncate_pagecache()
> call. This makes sense regardless of FOPEN_KEEP_CACHE or fc->writeback cache,
> so do it unconditionally.
>
> Can you please check out the following patch?
>
> Thanks,
> Miklos
>
> ---
> fs/fuse/file.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -198,12 +198,11 @@ void fuse_finish_open(struct inode *inod
> struct fuse_file *ff = file->private_data;
> struct fuse_conn *fc = get_fuse_conn(inode);
>
> - if (!(ff->open_flags & FOPEN_KEEP_CACHE))
> - invalidate_inode_pages2(inode->i_mapping);
> if (ff->open_flags & FOPEN_STREAM)
> stream_open(inode, file);
> else if (ff->open_flags & FOPEN_NONSEEKABLE)
> nonseekable_open(inode, file);
> +
> if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
> struct fuse_inode *fi = get_fuse_inode(inode);
>
> @@ -211,10 +210,14 @@ void fuse_finish_open(struct inode *inod
> fi->attr_version = atomic64_inc_return(&fc->attr_version);
> i_size_write(inode, 0);
> spin_unlock(&fi->lock);
> + truncate_pagecache(inode, 0);
> fuse_invalidate_attr(inode);
> if (fc->writeback_cache)
> file_update_time(file);
> + } else if (!(ff->open_flags & FOPEN_KEEP_CACHE)) {
> + invalidate_inode_pages2(inode->i_mapping);
> }
> +
> if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
> fuse_link_write_file(file);
> }
It looks good to me!
Thanks,
Yongji
