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

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Oct 08, 2020 at 01:01:59PM +0530, Chandan Babu R wrote:
> 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.

Oops, good catch!

--D

> -- 
> chandan
> 
> 
>