Re: [PATCH 3/6] xfs: update the file system geometry after recoverying superblock buffers

[Brian Foster <bfoster@redhat.com>]

On Mon, Oct 14, 2024 at 08:04:52AM +0200, Christoph Hellwig wrote:
> Primary superblock buffers that change the file system geometry after a
> growfs operation can affect the operation of later CIL checkpoints that
> make use of the newly added space and allocation groups.
> 
> Apply the changes to the in-memory structures as part of recovery pass 2,
> to ensure recovery works fine for such cases.
> 
> In the future we should apply the logic to other updates such as features
> bits as well.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/xfs_buf_item_recover.c | 52 +++++++++++++++++++++++++++++++++++
>  fs/xfs/xfs_log_recover.c      |  8 ------
>  2 files changed, 52 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c
> index 09e893cf563cb9..edf1162a8c9dd0 100644
> --- a/fs/xfs/xfs_buf_item_recover.c
> +++ b/fs/xfs/xfs_buf_item_recover.c
> @@ -22,6 +22,9 @@
>  #include "xfs_inode.h"
>  #include "xfs_dir2.h"
>  #include "xfs_quota.h"
> +#include "xfs_alloc.h"
> +#include "xfs_ag.h"
> +#include "xfs_sb.h"
>  
>  /*
>   * This is the number of entries in the l_buf_cancel_table used during
> @@ -684,6 +687,49 @@ xlog_recover_do_inode_buffer(
>  	return 0;
>  }
>  
> +/*
> + * Update the in-memory superblock and perag structures from the primary SB
> + * buffer.
> + *
> + * This is required because transactions running after growfs may require the
> + * updated values to be set in a previous fully commit transaction.
> + */
> +static int
> +xlog_recover_do_primary_sb_buffer(
> +	struct xfs_mount		*mp,
> +	struct xlog_recover_item	*item,
> +	struct xfs_buf			*bp,
> +	struct xfs_buf_log_format	*buf_f,
> +	xfs_lsn_t			current_lsn)
> +{
> +	struct xfs_dsb			*dsb = bp->b_addr;
> +	xfs_agnumber_t			orig_agcount = mp->m_sb.sb_agcount;
> +	int				error;
> +
> +	xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn);
> +
> +	/*
> +	 * Update the in-core super block from the freshly recovered on-disk one.
> +	 */
> +	xfs_sb_from_disk(&mp->m_sb, dsb);
> +
> +	/*
> +	 * Initialize the new perags, and also update various block and inode
> +	 * allocator setting based off the number of AGs or total blocks.
> +	 * Because of the latter this also needs to happen if the agcount did
> +	 * not change.
> +	 */
> +	error = xfs_initialize_perag(mp, orig_agcount,
> +			mp->m_sb.sb_agcount, mp->m_sb.sb_dblocks,
> +			&mp->m_maxagi);
> +	if (error) {
> +		xfs_warn(mp, "Failed recovery per-ag init: %d", error);
> +		return error;
> +	}
> +	mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
> +	return 0;
> +}
> +
>  /*
>   * V5 filesystems know the age of the buffer on disk being recovered. We can
>   * have newer objects on disk than we are replaying, and so for these cases we
> @@ -967,6 +1013,12 @@ xlog_recover_buf_commit_pass2(
>  		dirty = xlog_recover_do_dquot_buffer(mp, log, item, bp, buf_f);
>  		if (!dirty)
>  			goto out_release;
> +	} else if ((xfs_blft_from_flags(buf_f) & XFS_BLFT_SB_BUF) &&
> +			xfs_buf_daddr(bp) == 0) {
> +		error = xlog_recover_do_primary_sb_buffer(mp, item, bp, buf_f,
> +				current_lsn);
> +		if (error)
> +			goto out_release;
>  	} else {
>  		xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn);
>  	}
> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> index 60d46338f51792..08b8938e4efb7d 100644
> --- a/fs/xfs/xfs_log_recover.c
> +++ b/fs/xfs/xfs_log_recover.c
> @@ -3346,7 +3346,6 @@ xlog_do_recover(
>  	struct xfs_mount	*mp = log->l_mp;
>  	struct xfs_buf		*bp = mp->m_sb_bp;
>  	struct xfs_sb		*sbp = &mp->m_sb;
> -	xfs_agnumber_t		orig_agcount = sbp->sb_agcount;
>  	int			error;
>  
>  	trace_xfs_log_recover(log, head_blk, tail_blk);
> @@ -3394,13 +3393,6 @@ xlog_do_recover(
>  	/* re-initialise in-core superblock and geometry structures */
>  	mp->m_features |= xfs_sb_version_to_features(sbp);
>  	xfs_reinit_percpu_counters(mp);
> -	error = xfs_initialize_perag(mp, orig_agcount, sbp->sb_agcount,
> -			sbp->sb_dblocks, &mp->m_maxagi);
> -	if (error) {
> -		xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
> -		return error;
> -	}
> -	mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
>  
>  	/* Normal transactions can now occur */
>  	clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
> -- 
> 2.45.2
> 
>