Re: [PATCH 09/10] fuse mount: Do not set sync_init when sync_init was not used

[Bernd Schubert <bernd@bsbernd.com>]

On 5/9/26 02:35, Darrick J. Wong wrote:
> On Fri, May 08, 2026 at 06:39:12PM +0200, Bernd Schubert via B4 Relay wrote:
>> From: Bernd Schubert <bernd@bsbernd.com>
>>
>> synchronous init is just a hint and we cannot fail on it, but for
>> daemonization we need to do know when it was actually used.
>> Bug was that se->sync_init() was set unconditionally on mount success.
>>
>> Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
>> ---
>>  lib/fuse_lowlevel.c | 22 +++++++++++++++-------
>>  1 file changed, 15 insertions(+), 7 deletions(-)
>>
>> diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
>> index 6e078e82..60b936c3 100644
>> --- a/lib/fuse_lowlevel.c
>> +++ b/lib/fuse_lowlevel.c
>> @@ -4471,10 +4471,13 @@ static void *session_sync_init_worker(void *data)
>>  }
>>  
>>  /* Enable synchronous FUSE_INIT and start worker thread */
>> -static int session_start_sync_init(struct fuse_session *se, int fd)
>> +static int session_start_sync_init(struct fuse_session *se, int fd,
>> +				   bool *is_sync_init)
>>  {
>>  	int err, res;
>>  
>> +	*is_sync_init = false;
>> +
>>  	/*
>>  	 * Older fuse servers do not set want_sync_init or start the new
>>  	 * daemonize code, so they get async init.
>> @@ -4536,6 +4539,8 @@ static int session_start_sync_init(struct fuse_session *se, int fd)
>>  		return -EIO;
>>  	}
>>  
>> +	*is_sync_init = true;
> 
> Hrm.  So we only end up with return value == 0 and *is_sync_init==true
> if SYNC_INIT was enabled via ioctl and all the pthread stuff is ready to
> go.  The other two outcomes are:
> 
> 1. return == 0 && *is_sync_init==false if the kernel didn't let us use
>    synchronous init
> 
> 2. return != 0 if something broke and we just want to abort
> 
> If that's all correct then I've understood this patch well enough to say

Exactly! I'm going to amend the commit message.

> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
> 
> --D
> 


Thanks,
Bernd