Re: [PATCH v4 14/16] bcachefs: add pre-content fsnotify hook to fault

Jan Kara
2024-08-29T11:11:01Z

On Wed 14-08-24 17:25:32, Josef Bacik wrote:
> bcachefs has its own locking around filemap_fault, so we have to make
> sure we do the fsnotify hook before the locking. Add the check to emit
> the event before the locking and return VM_FAULT_RETRY to retrigger the
> fault once the event has been emitted.
>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>

Looks good to me. Would be nice to get ack from bcachefs guys. Kent?

Honza

> ---
> fs/bcachefs/fs-io-pagecache.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/fs/bcachefs/fs-io-pagecache.c b/fs/bcachefs/fs-io-pagecache.c
> index a9cc5cad9cc9..1fa1f1ac48c8 100644
> --- a/fs/bcachefs/fs-io-pagecache.c
> +++ b/fs/bcachefs/fs-io-pagecache.c
> @@ -570,6 +570,10 @@ vm_fault_t bch2_page_fault(struct vm_fault *vmf)
> if (fdm == mapping)
> return VM_FAULT_SIGBUS;
>
> + ret = filemap_maybe_emit_fsnotify_event(vmf);
> + if (unlikely(ret))
> + return ret;
> +
> /* Lock ordering: */
> if (fdm > mapping) {
> struct bch_inode_info *fdm_host = to_bch_ei(fdm->host);
> --
> 2.43.0
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR