Re: [PATCH 2/2] xfs: make xfs_growfs_rt update secondary superblocks

[Chandan Babu R <chandanrlinux@gmail.com>]

On Thursday 8 October 2020 9:26:12 AM IST Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> When we call growfs on the data device, we update the secondary
> superblocks to reflect the updated filesystem geometry.  We need to do
> this for growfs on the realtime volume too, because a future xfs_repair
> run could try to fix the filesystem using a backup superblock.
> 
> This was observed by the online superblock scrubbers while running
> xfs/233.  One can also trigger this by growing an rt volume, cycling the
> mount, and creating new rt files.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/xfs_rtalloc.c |    7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> 
> diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
> index 1c3969807fb9..5b2e68d9face 100644
> --- a/fs/xfs/xfs_rtalloc.c
> +++ b/fs/xfs/xfs_rtalloc.c
> @@ -18,7 +18,7 @@
>  #include "xfs_trans_space.h"
>  #include "xfs_icache.h"
>  #include "xfs_rtalloc.h"
> -
> +#include "xfs_sb.h"
>  
>  /*
>   * Read and return the summary information for a given extent size,
> @@ -1108,6 +1108,11 @@ xfs_growfs_rt(
>  	 */
>  	kmem_free(nmp);
>  
> +	/* Update secondary superblocks now the physical grow has completed */
> +	error = xfs_update_secondary_sbs(mp);
> +	if (error)
> +		return error;
> +

If any of the operations in the previous "for" loop causes "error" to be set
and the loop to be exited, the call to xfs_update_secondary_sbs() would
overwrite this error value. In the worst case it might set error to 0 and
hence return a success status to the caller when the growfs operation
had actually failed.

-- 
chandan