Re: [PATCH 23/28] open-by-handle.c: use syncfs() rather than sync()

["Nirjhar Roy (IBM)" <nirjhar.roy.lists@gmail.com>]

On Thu, 2025-04-17 at 13:01 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> generic/467 runs open_by_handle at least 15 times. Each
> execution runs sync() at least once, sometimes three times.
> 
> When running check-parallel, sync() can take a -long- time to
> run as there can be dozens of filesystems that need to be synced,
> not to mention sync getting hung up behind all the mount and
> unmounts that are also being run. This results in:
> 
> Ten slowest tests - runtime in seconds:
> generic/467 442
> .....
> 
> This test running for a really long time.
> 
> Convert the sync() calls to syncfs() so that they only try to sync
> the filesystem under test and not the entire system. This avoids
> interactions and delays with other tests and mount/unmount
> operations, hence allowing both the test and the overall
> check-parallel operation to run faster:
> 
> generic/467        6s
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  src/open_by_handle.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/src/open_by_handle.c b/src/open_by_handle.c
> index a99cce4b3..816bb5d12 100644
> --- a/src/open_by_handle.c
> +++ b/src/open_by_handle.c
> @@ -430,7 +430,7 @@ int main(int argc, char **argv)
>  	}
>  
>  	/* sync to get the new inodes to hit the disk */
> -	sync();
> +	syncfs(mount_fd);
>  
>  	/*
>  	 * encode the file handles or read them from file (-i) and
> maybe store
> @@ -563,10 +563,10 @@ int main(int argc, char **argv)
>  	}
>  
>  	/* sync to get log forced for unlink transactions to hit the
> disk */
> -	sync();
> +	syncfs(mount_fd);
>  
>  	/* sync once more FTW */
> -	sync();
> +	syncfs(mount_fd);
I don't see mount_fd being closed at the end. Maybe all the file
descriptors are closed after the program finishes execution?
Other than this:
Feel free to add 
Reviewed-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>

>  
>  	/*
>  	 * now drop the caches so that unlinked inodes are reclaimed
> and