Re: [fuse-devel] [PATCH] fuse: avoid deadlock when write fuse inode
From: Miklos Szeredi
Date: Wed Mar 24 2021 - 11:29:53 EST
On Tue, Feb 2, 2021 at 5:41 AM Huang Jianan via fuse-devel
<fuse-devel@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> We found the following deadlock situations in low memory scenarios:
> Thread A Thread B
> - __writeback_single_inode
> - fuse_write_inode
> - fuse_simple_request
> - __fuse_request_send
> - request_wait_answer
> - fuse_dev_splice_read
> - fuse_copy_fill
> - __alloc_pages_direct_reclaim
> - do_shrink_slab
> - super_cache_scan
> - shrink_dentry_list
> - dentry_unlink_inode
> - iput_final
> - inode_wait_for_writeback
On what kernel are you seeing this?
I don't see how it can happen on upstream kernels, since there's a
"write_inode_now(inode, 1)" call in fuse_release() and nothing can
dirty the inode after the file has been released.
Thanks,
Miklos