Re: [PATCH 06/11] xfs: kill struct xfs_iomap

[Alex Elder <aelder@sgi.com>]

On Wed, 2010-04-28 at 08:28 -0400, Christoph Hellwig wrote:
> plain text document attachment (xfs-iomap-cleanup-6)
> Now that struct xfs_iomap contains exactly the same units as
> struct xfs_bmbt_irec we can just use the latter directly in the aops
> code.  Replace the missing IOMAP_NEW flag with a new boolean output
> parameter to xfs_iomap.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good.  My only suggestion was going to be having xfs_iomap()
support passing a null pointer for "new" if it's a don't-care in
the caller, but in the end it's called in only two spots and the
result would not be an improvement.

Reviewed-by: Alex Elder <aelder@sgi.com>

> Index: xfs/fs/xfs/linux-2.6/xfs_aops.c
> ===================================================================
> --- xfs.orig/fs/xfs/linux-2.6/xfs_aops.c	2010-04-27 17:39:20.699003542 +0200
> +++ xfs/fs/xfs/linux-2.6/xfs_aops.c	2010-04-27 18:12:14.223025612 +0200
> @@ -309,23 +309,24 @@ xfs_map_blocks(
>  	struct inode		*inode,
>  	loff_t			offset,
>  	ssize_t			count,
> -	xfs_iomap_t		*mapp,
> +	struct xfs_bmbt_irec	*imap,
>  	int			flags)
>  {
>  	int			nmaps = 1;
> +	int			new = 0;
>  
> -	return -xfs_iomap(XFS_I(inode), offset, count, flags, mapp, &nmaps);
> +	return -xfs_iomap(XFS_I(inode), offset, count, flags, imap, &nmaps, &new);
>  }
>  
>  STATIC int
>  xfs_iomap_valid(
>  	struct inode		*inode,
> -	xfs_iomap_t		*iomapp,
> +	struct xfs_bmbt_irec	*imap,
>  	loff_t			offset)
>  {
>  	struct xfs_mount	*mp = XFS_I(inode)->i_mount;
> -	xfs_off_t		iomap_offset = XFS_FSB_TO_B(mp, iomapp->iomap_offset);
> -	xfs_off_t		iomap_bsize = XFS_FSB_TO_B(mp, iomapp->iomap_bsize);
> +	xfs_off_t		iomap_offset = XFS_FSB_TO_B(mp, imap->br_startoff);
> +	xfs_off_t		iomap_bsize = XFS_FSB_TO_B(mp, imap->br_blockcount);
>  
>  	return offset >= iomap_offset &&
>  		offset < iomap_offset + iomap_bsize;
> @@ -561,16 +562,16 @@ STATIC void
>  xfs_map_buffer(
>  	struct inode		*inode,
>  	struct buffer_head	*bh,
> -	xfs_iomap_t		*mp,
> +	struct xfs_bmbt_irec	*imap,
>  	xfs_off_t		offset)
>  {
>  	sector_t		bn;
>  	struct xfs_mount	*m = XFS_I(inode)->i_mount;
> -	xfs_off_t		iomap_offset = XFS_FSB_TO_B(m, mp->iomap_offset);
> -	xfs_daddr_t		iomap_bn = xfs_fsb_to_db(XFS_I(inode), mp->iomap_bn);
> +	xfs_off_t		iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff);
> +	xfs_daddr_t		iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock);
>  
> -	ASSERT(mp->iomap_bn != HOLESTARTBLOCK);
> -	ASSERT(mp->iomap_bn != DELAYSTARTBLOCK);
> +	ASSERT(imap->br_startblock != HOLESTARTBLOCK);
> +	ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
>  
>  	bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) +
>  	      ((offset - iomap_offset) >> inode->i_blkbits);
> @@ -585,14 +586,14 @@ STATIC void
>  xfs_map_at_offset(
>  	struct inode		*inode,
>  	struct buffer_head	*bh,
> -	xfs_iomap_t		*iomapp,
> +	struct xfs_bmbt_irec	*imap,
>  	xfs_off_t		offset)
>  {
> -	ASSERT(iomapp->iomap_bn != HOLESTARTBLOCK);
> -	ASSERT(iomapp->iomap_bn != DELAYSTARTBLOCK);
> +	ASSERT(imap->br_startblock != HOLESTARTBLOCK);
> +	ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
>  
>  	lock_buffer(bh);
> -	xfs_map_buffer(inode, bh, iomapp, offset);
> +	xfs_map_buffer(inode, bh, imap, offset);
>  	bh->b_bdev = xfs_find_bdev_for_inode(inode);
>  	set_buffer_mapped(bh);
>  	clear_buffer_delay(bh);
> @@ -749,7 +750,7 @@ xfs_convert_page(
>  	struct inode		*inode,
>  	struct page		*page,
>  	loff_t			tindex,
> -	xfs_iomap_t		*mp,
> +	struct xfs_bmbt_irec	*imap,
>  	xfs_ioend_t		**ioendp,
>  	struct writeback_control *wbc,
>  	int			startio,
> @@ -814,15 +815,15 @@ xfs_convert_page(
>  			else
>  				type = IOMAP_DELAY;
>  
> -			if (!xfs_iomap_valid(inode, mp, offset)) {
> +			if (!xfs_iomap_valid(inode, imap, offset)) {
>  				done = 1;
>  				continue;
>  			}
>  
> -			ASSERT(mp->iomap_bn != HOLESTARTBLOCK);
> -			ASSERT(mp->iomap_bn != DELAYSTARTBLOCK);
> +			ASSERT(imap->br_startblock != HOLESTARTBLOCK);
> +			ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
>  
> -			xfs_map_at_offset(inode, bh, mp, offset);
> +			xfs_map_at_offset(inode, bh, imap, offset);
>  			if (startio) {
>  				xfs_add_to_ioend(inode, bh, offset,
>  						type, ioendp, done);
> @@ -874,7 +875,7 @@ STATIC void
>  xfs_cluster_write(
>  	struct inode		*inode,
>  	pgoff_t			tindex,
> -	xfs_iomap_t		*iomapp,
> +	struct xfs_bmbt_irec	*imap,
>  	xfs_ioend_t		**ioendp,
>  	struct writeback_control *wbc,
>  	int			startio,
> @@ -893,7 +894,7 @@ xfs_cluster_write(
>  
>  		for (i = 0; i < pagevec_count(&pvec); i++) {
>  			done = xfs_convert_page(inode, pvec.pages[i], tindex++,
> -					iomapp, ioendp, wbc, startio, all_bh);
> +					imap, ioendp, wbc, startio, all_bh);
>  			if (done)
>  				break;
>  		}
> @@ -1050,7 +1051,7 @@ xfs_page_state_convert(
>  	int		unmapped) /* also implies page uptodate */
>  {
>  	struct buffer_head	*bh, *head;
> -	xfs_iomap_t		iomap;
> +	struct xfs_bmbt_irec	imap;
>  	xfs_ioend_t		*ioend = NULL, *iohead = NULL;
>  	loff_t			offset;
>  	unsigned long           p_offset = 0;
> @@ -1124,7 +1125,7 @@ xfs_page_state_convert(
>  		}
>  
>  		if (iomap_valid)
> -			iomap_valid = xfs_iomap_valid(inode, &iomap, offset);
> +			iomap_valid = xfs_iomap_valid(inode, &imap, offset);
>  
>  		/*
>  		 * First case, map an unwritten extent and prepare for
> @@ -1176,13 +1177,13 @@ xfs_page_state_convert(
>  				}
>  
>  				err = xfs_map_blocks(inode, offset, size,
> -						&iomap, flags);
> +						&imap, flags);
>  				if (err)
>  					goto error;
> -				iomap_valid = xfs_iomap_valid(inode, &iomap, offset);
> +				iomap_valid = xfs_iomap_valid(inode, &imap, offset);
>  			}
>  			if (iomap_valid) {
> -				xfs_map_at_offset(inode, bh, &iomap, offset);
> +				xfs_map_at_offset(inode, bh, &imap, offset);
>  				if (startio) {
>  					xfs_add_to_ioend(inode, bh, offset,
>  							type, &ioend,
> @@ -1206,10 +1207,10 @@ xfs_page_state_convert(
>  				size = xfs_probe_cluster(inode, page, bh,
>  								head, 1);
>  				err = xfs_map_blocks(inode, offset, size,
> -						&iomap, flags);
> +						&imap, flags);
>  				if (err)
>  					goto error;
> -				iomap_valid = xfs_iomap_valid(inode, &iomap, offset);
> +				iomap_valid = xfs_iomap_valid(inode, &imap, offset);
>  			}
>  
>  			/*
> @@ -1250,13 +1251,13 @@ xfs_page_state_convert(
>  
>  	if (ioend && iomap_valid) {
>  		struct xfs_mount	*m = XFS_I(inode)->i_mount;
> -		xfs_off_t		iomap_offset = XFS_FSB_TO_B(m, iomap.iomap_offset);
> -		xfs_off_t		iomap_bsize = XFS_FSB_TO_B(m, iomap.iomap_bsize);
> +		xfs_off_t		iomap_offset = XFS_FSB_TO_B(m, imap.br_startoff);
> +		xfs_off_t		iomap_bsize = XFS_FSB_TO_B(m, imap.br_blockcount);
>  
>  		offset = (iomap_offset + iomap_bsize - 1) >>
>  					PAGE_CACHE_SHIFT;
>  		tlast = min_t(pgoff_t, offset, last_index);
> -		xfs_cluster_write(inode, page->index + 1, &iomap, &ioend,
> +		xfs_cluster_write(inode, page->index + 1, &imap, &ioend,
>  					wbc, startio, all_bh, tlast);
>  	}
>  
> @@ -1459,10 +1460,11 @@ __xfs_get_blocks(
>  	int			direct,
>  	bmapi_flags_t		flags)
>  {
> -	xfs_iomap_t		iomap;
> +	struct xfs_bmbt_irec	imap;
>  	xfs_off_t		offset;
>  	ssize_t			size;
> -	int			niomap = 1;
> +	int			nimap = 1;
> +	int			new = 0;
>  	int			error;
>  
>  	offset = (xfs_off_t)iblock << inode->i_blkbits;
> @@ -1473,21 +1475,21 @@ __xfs_get_blocks(
>  		return 0;
>  
>  	error = xfs_iomap(XFS_I(inode), offset, size,
> -			     create ? flags : BMAPI_READ, &iomap, &niomap);
> +			     create ? flags : BMAPI_READ, &imap, &nimap, &new);
>  	if (error)
>  		return -error;
> -	if (niomap == 0)
> +	if (nimap == 0)
>  		return 0;
>  
> -	if (iomap.iomap_bn != HOLESTARTBLOCK &&
> -	    iomap.iomap_bn != DELAYSTARTBLOCK) {
> +	if (imap.br_startblock != HOLESTARTBLOCK &&
> +	    imap.br_startblock != DELAYSTARTBLOCK) {
>  		/*
>  		 * For unwritten extents do not report a disk address on
>  		 * the read case (treat as if we're reading into a hole).
>  		 */
> -		if (create || !(iomap.iomap_flags & IOMAP_UNWRITTEN))
> -			xfs_map_buffer(inode, bh_result, &iomap, offset);
> -		if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) {
> +		if (create || !ISUNWRITTEN(&imap))
> +			xfs_map_buffer(inode, bh_result, &imap, offset);
> +		if (create && ISUNWRITTEN(&imap)) {
>  			if (direct)
>  				bh_result->b_private = inode;
>  			set_buffer_unwritten(bh_result);
> @@ -1512,10 +1514,10 @@ __xfs_get_blocks(
>  	if (create &&
>  	    ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
>  	     (offset >= i_size_read(inode)) ||
> -	     (iomap.iomap_flags & (IOMAP_NEW|IOMAP_UNWRITTEN))))
> +	     (new || ISUNWRITTEN(&imap))))
>  		set_buffer_new(bh_result);
>  
> -	if (iomap.iomap_bn == DELAYSTARTBLOCK) {
> +	if (imap.br_startblock == DELAYSTARTBLOCK) {
>  		BUG_ON(direct);
>  		if (create) {
>  			set_buffer_uptodate(bh_result);
> @@ -1526,9 +1528,9 @@ __xfs_get_blocks(
>  
>  	if (direct || size > (1 << inode->i_blkbits)) {
>  		struct xfs_mount	*mp = XFS_I(inode)->i_mount;
> -		xfs_off_t		iomap_offset = XFS_FSB_TO_B(mp, iomap.iomap_offset);
> +		xfs_off_t		iomap_offset = XFS_FSB_TO_B(mp, imap.br_startoff);
>  		xfs_off_t		iomap_delta = offset - iomap_offset;
> -		xfs_off_t		iomap_bsize = XFS_FSB_TO_B(mp, iomap.iomap_bsize);
> +		xfs_off_t		iomap_bsize = XFS_FSB_TO_B(mp, imap.br_blockcount);
>  
>  		ASSERT(iomap_bsize - iomap_delta > 0);
>  		offset = min_t(xfs_off_t,
> Index: xfs/fs/xfs/xfs_iomap.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_iomap.c	2010-04-27 17:39:20.700004101 +0200
> +++ xfs/fs/xfs/xfs_iomap.c	2010-04-27 18:12:21.135027288 +0200
> @@ -55,46 +55,25 @@
>  #define XFS_STRAT_WRITE_IMAPS	2
>  #define XFS_WRITE_IMAPS		XFS_BMAP_MAX_NMAP
>  
> -STATIC void
> -xfs_imap_to_bmap(
> -	xfs_inode_t	*ip,
> -	xfs_off_t	offset,
> -	xfs_bmbt_irec_t *imap,
> -	xfs_iomap_t	*iomapp,
> -	int		imaps,			/* Number of imap entries */
> -	int		flags)
> -{
> -	iomapp->iomap_offset = imap->br_startoff;
> -	iomapp->iomap_bsize = imap->br_blockcount;
> -	iomapp->iomap_flags = flags;
> -	iomapp->iomap_bn = imap->br_startblock;
> -
> -	if (imap->br_startblock != HOLESTARTBLOCK &&
> -	    imap->br_startblock != DELAYSTARTBLOCK &&
> -	    ISUNWRITTEN(imap))
> -		iomapp->iomap_flags |= IOMAP_UNWRITTEN;
> -}
> -
>  int
>  xfs_iomap(
> -	xfs_inode_t	*ip,
> -	xfs_off_t	offset,
> -	ssize_t		count,
> -	int		flags,
> -	xfs_iomap_t	*iomapp,
> -	int		*niomaps)
> +	struct xfs_inode	*ip,
> +	xfs_off_t		offset,
> +	ssize_t			count,
> +	int			flags,
> +	struct xfs_bmbt_irec	*imap,
> +	int			*nimaps,
> +	int			*new)
>  {
> -	xfs_mount_t	*mp = ip->i_mount;
> -	xfs_fileoff_t	offset_fsb, end_fsb;
> -	int		error = 0;
> -	int		lockmode = 0;
> -	xfs_bmbt_irec_t	imap;
> -	int		nimaps = 1;
> -	int		bmapi_flags = 0;
> -	int		iomap_flags = 0;
> +	struct xfs_mount	*mp = ip->i_mount;
> +	xfs_fileoff_t		offset_fsb, end_fsb;
> +	int			error = 0;
> +	int			lockmode = 0;
> +	int			bmapi_flags = 0;
>  
>  	ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
> -	ASSERT(niomaps && *niomaps == 1);
> +
> +	*new = 0;
>  
>  	if (XFS_FORCED_SHUTDOWN(mp))
>  		return XFS_ERROR(EIO);
> @@ -136,8 +115,8 @@ xfs_iomap(
>  
>  	error = xfs_bmapi(NULL, ip, offset_fsb,
>  			(xfs_filblks_t)(end_fsb - offset_fsb),
> -			bmapi_flags,  NULL, 0, &imap,
> -			&nimaps, NULL, NULL);
> +			bmapi_flags,  NULL, 0, imap,
> +			nimaps, NULL, NULL);
>  
>  	if (error)
>  		goto out;
> @@ -145,45 +124,41 @@ xfs_iomap(
>  	switch (flags & (BMAPI_WRITE|BMAPI_ALLOCATE)) {
>  	case BMAPI_WRITE:
>  		/* If we found an extent, return it */
> -		if (nimaps &&
> -		    (imap.br_startblock != HOLESTARTBLOCK) &&
> -		    (imap.br_startblock != DELAYSTARTBLOCK)) {
> -			trace_xfs_iomap_found(ip, offset, count, flags, &imap);
> +		if (*nimaps &&
> +		    (imap->br_startblock != HOLESTARTBLOCK) &&
> +		    (imap->br_startblock != DELAYSTARTBLOCK)) {
> +			trace_xfs_iomap_found(ip, offset, count, flags, imap);
>  			break;
>  		}
>  
>  		if (flags & (BMAPI_DIRECT|BMAPI_MMAP)) {
>  			error = xfs_iomap_write_direct(ip, offset, count, flags,
> -						       &imap, &nimaps, nimaps);
> +						       imap, nimaps, *nimaps);
>  		} else {
>  			error = xfs_iomap_write_delay(ip, offset, count, flags,
> -						      &imap, &nimaps);
> +						      imap, nimaps);
>  		}
>  		if (!error) {
> -			trace_xfs_iomap_alloc(ip, offset, count, flags, &imap);
> +			trace_xfs_iomap_alloc(ip, offset, count, flags, imap);
>  		}
> -		iomap_flags = IOMAP_NEW;
> +		*new = 1;
>  		break;
>  	case BMAPI_ALLOCATE:
>  		/* If we found an extent, return it */
>  		xfs_iunlock(ip, lockmode);
>  		lockmode = 0;
>  
> -		if (nimaps && !isnullstartblock(imap.br_startblock)) {
> -			trace_xfs_iomap_found(ip, offset, count, flags, &imap);
> +		if (*nimaps && !isnullstartblock(imap->br_startblock)) {
> +			trace_xfs_iomap_found(ip, offset, count, flags, imap);
>  			break;
>  		}
>  
>  		error = xfs_iomap_write_allocate(ip, offset, count,
> -						 &imap, &nimaps);
> +						 imap, nimaps);
>  		break;
>  	}
>  
> -	ASSERT(nimaps <= 1);
> -
> -	if (nimaps)
> -		xfs_imap_to_bmap(ip, offset, &imap, iomapp, nimaps, iomap_flags);
> -	*niomaps = nimaps;
> +	ASSERT(*nimaps <= 1);
>  
>  out:
>  	if (lockmode)
> @@ -191,7 +166,6 @@ out:
>  	return XFS_ERROR(error);
>  }
>  
> -
>  STATIC int
>  xfs_iomap_eof_align_last_fsb(
>  	xfs_mount_t	*mp,
> Index: xfs/fs/xfs/xfs_iomap.h
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_iomap.h	2010-04-27 17:39:27.783067167 +0200
> +++ xfs/fs/xfs/xfs_iomap.h	2010-04-27 18:12:14.232003612 +0200
> @@ -47,35 +47,11 @@ typedef enum {
>  	{ BMAPI_MMAP,		"MMAP" }, \
>  	{ BMAPI_TRYLOCK,	"TRYLOCK" }
>  
> -/*
> - * xfs_iomap_t:  File system I/O map
> - *
> - * The iomap_bn field is expressed in 512-byte blocks, and is where the
> - * mapping starts on disk.
> - *
> - * The iomap_offset, iomap_bsize and iomap_delta fields are in bytes.
> - * iomap_offset is the offset of the mapping in the file itself.
> - * iomap_bsize is the size of the mapping,  iomap_delta is the
> - * desired data's offset into the mapping, given the offset supplied
> - * to the file I/O map routine.
> - *
> - * When a request is made to read beyond the logical end of the object,
> - * iomap_size may be set to 0, but iomap_offset and iomap_length should be set
> - * to the actual amount of underlying storage that has been allocated, if any.
> - */
> -
> -typedef struct xfs_iomap {
> -	xfs_daddr_t		iomap_bn;	/* first 512B blk of mapping */
> -	xfs_off_t		iomap_offset;	/* offset of mapping, bytes */
> -	xfs_off_t		iomap_bsize;	/* size of mapping, bytes */
> -	iomap_flags_t		iomap_flags;
> -} xfs_iomap_t;
> -
>  struct xfs_inode;
>  struct xfs_bmbt_irec;
>  
>  extern int xfs_iomap(struct xfs_inode *, xfs_off_t, ssize_t, int,
> -		     struct xfs_iomap *, int *);
> +		     struct xfs_bmbt_irec *, int *, int *);
>  extern int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
>  				  int, struct xfs_bmbt_irec *, int *, int);
>  extern int xfs_iomap_write_delay(struct xfs_inode *, xfs_off_t, size_t, int,
> 
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