Re: [PATCH 05/11] xfs: make xfs_bmbt_to_iomap more useful

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

On Mon, Dec 03, 2018 at 05:24:57PM -0500, Christoph Hellwig wrote:
> Move checking for invalid zero blocks and setting of various iomap flags
> into this helper.  Also make it deal with "raw" delalloc extents to
> avoid clutter in the callers.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_iomap.c | 84 +++++++++++++++++++++-------------------------
>  fs/xfs/xfs_iomap.h |  4 +--
>  fs/xfs/xfs_pnfs.c  |  2 +-
>  3 files changed, 41 insertions(+), 49 deletions(-)
> 
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 6acfed2ae858..9f1fd224bb06 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -35,18 +35,40 @@
>  #define XFS_WRITEIO_ALIGN(mp,off)	(((off) >> mp->m_writeio_log) \
>  						<< mp->m_writeio_log)
>  
> -void
> +static int
> +xfs_alert_fsblock_zero(
> +	xfs_inode_t	*ip,
> +	xfs_bmbt_irec_t	*imap)
> +{
> +	xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
> +			"Access to block zero in inode %llu "
> +			"start_block: %llx start_off: %llx "
> +			"blkcnt: %llx extent-state: %x",
> +		(unsigned long long)ip->i_ino,
> +		(unsigned long long)imap->br_startblock,
> +		(unsigned long long)imap->br_startoff,
> +		(unsigned long long)imap->br_blockcount,
> +		imap->br_state);
> +	return -EFSCORRUPTED;
> +}
> +
> +int
>  xfs_bmbt_to_iomap(
>  	struct xfs_inode	*ip,
>  	struct iomap		*iomap,
> -	struct xfs_bmbt_irec	*imap)
> +	struct xfs_bmbt_irec	*imap,
> +	bool			shared)
>  {
>  	struct xfs_mount	*mp = ip->i_mount;
>  
> +	if (unlikely(!imap->br_startblock && !XFS_IS_REALTIME_INODE(ip)))
> +		return xfs_alert_fsblock_zero(ip, imap);
> +
>  	if (imap->br_startblock == HOLESTARTBLOCK) {
>  		iomap->addr = IOMAP_NULL_ADDR;
>  		iomap->type = IOMAP_HOLE;
> -	} else if (imap->br_startblock == DELAYSTARTBLOCK) {
> +	} else if (imap->br_startblock == DELAYSTARTBLOCK ||
> +		   isnullstartblock(imap->br_startblock)) {
>  		iomap->addr = IOMAP_NULL_ADDR;
>  		iomap->type = IOMAP_DELALLOC;
>  	} else {
> @@ -60,6 +82,13 @@ xfs_bmbt_to_iomap(
>  	iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
>  	iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));
>  	iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
> +
> +	if (xfs_ipincount(ip) &&
> +	    (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
> +		iomap->flags |= IOMAP_F_DIRTY;
> +	if (shared)
> +		iomap->flags |= IOMAP_F_SHARED;
> +	return 0;
>  }
>  
>  static void
> @@ -138,23 +167,6 @@ xfs_iomap_eof_align_last_fsb(
>  	return 0;
>  }
>  
> -STATIC int
> -xfs_alert_fsblock_zero(
> -	xfs_inode_t	*ip,
> -	xfs_bmbt_irec_t	*imap)
> -{
> -	xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
> -			"Access to block zero in inode %llu "
> -			"start_block: %llx start_off: %llx "
> -			"blkcnt: %llx extent-state: %x",
> -		(unsigned long long)ip->i_ino,
> -		(unsigned long long)imap->br_startblock,
> -		(unsigned long long)imap->br_startoff,
> -		(unsigned long long)imap->br_blockcount,
> -		imap->br_state);
> -	return -EFSCORRUPTED;
> -}
> -
>  int
>  xfs_iomap_write_direct(
>  	xfs_inode_t	*ip,
> @@ -649,17 +661,7 @@ xfs_file_iomap_begin_delay(
>  	iomap->flags |= IOMAP_F_NEW;
>  	trace_xfs_iomap_alloc(ip, offset, count, XFS_DATA_FORK, &got);
>  done:
> -	if (isnullstartblock(got.br_startblock))
> -		got.br_startblock = DELAYSTARTBLOCK;
> -
> -	if (!got.br_startblock) {
> -		error = xfs_alert_fsblock_zero(ip, &got);
> -		if (error)
> -			goto out_unlock;
> -	}
> -
> -	xfs_bmbt_to_iomap(ip, iomap, &got);
> -
> +	error = xfs_bmbt_to_iomap(ip, iomap, &got, false);
>  out_unlock:
>  	xfs_iunlock(ip, XFS_ILOCK_EXCL);
>  	return error;
> @@ -1097,15 +1099,7 @@ xfs_file_iomap_begin(
>  	trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
>  
>  out_finish:
> -	if (xfs_ipincount(ip) && (ip->i_itemp->ili_fsync_fields
> -				& ~XFS_ILOG_TIMESTAMP))
> -		iomap->flags |= IOMAP_F_DIRTY;
> -
> -	xfs_bmbt_to_iomap(ip, iomap, &imap);
> -
> -	if (shared)
> -		iomap->flags |= IOMAP_F_SHARED;
> -	return 0;
> +	return xfs_bmbt_to_iomap(ip, iomap, &imap, shared);
>  
>  out_found:
>  	ASSERT(nimaps);
> @@ -1228,12 +1222,10 @@ xfs_xattr_iomap_begin(
>  out_unlock:
>  	xfs_iunlock(ip, lockmode);
>  
> -	if (!error) {
> -		ASSERT(nimaps);
> -		xfs_bmbt_to_iomap(ip, iomap, &imap);
> -	}
> -
> -	return error;
> +	if (error)
> +		return error;
> +	ASSERT(nimaps);
> +	return xfs_bmbt_to_iomap(ip, iomap, &imap, false);
>  }
>  
>  const struct iomap_ops xfs_xattr_iomap_ops = {
> diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
> index c6170548831b..ed27e41b687c 100644
> --- a/fs/xfs/xfs_iomap.h
> +++ b/fs/xfs/xfs_iomap.h
> @@ -17,8 +17,8 @@ int xfs_iomap_write_allocate(struct xfs_inode *, int, xfs_off_t,
>  			struct xfs_bmbt_irec *, unsigned int *);
>  int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, xfs_off_t, bool);
>  
> -void xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
> -		struct xfs_bmbt_irec *);
> +int xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
> +		struct xfs_bmbt_irec *, bool shared);
>  xfs_extlen_t xfs_eof_alignment(struct xfs_inode *ip, xfs_extlen_t extsize);
>  
>  static inline xfs_filblks_t
> diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
> index f44c3599527d..bde2c9f56a46 100644
> --- a/fs/xfs/xfs_pnfs.c
> +++ b/fs/xfs/xfs_pnfs.c
> @@ -185,7 +185,7 @@ xfs_fs_map_blocks(
>  	}
>  	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
>  
> -	xfs_bmbt_to_iomap(ip, iomap, &imap);
> +	error = xfs_bmbt_to_iomap(ip, iomap, &imap, false);
>  	*device_generation = mp->m_generation;
>  	return error;
>  out_unlock:
> -- 
> 2.19.1
>