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Commit b447fe5a authored by Dave Chinner's avatar Dave Chinner Committed by Alex Elder
Browse files

xfs: factor unwritten extent map manipulations out of xfs_bmapi 



To further improve the readability of xfs_bmapi(), factor the
unwritten extent conversion out into a separate function. This
removes large block of logic from the xfs_bmapi() code loop and
makes it easier to see the operational logic flow for xfs_bmapi().

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAlex Elder <aelder@sgi.com>
parent 7e47a4ef

fs/xfs/xfs_bmap.c

+70 −37
Original line number Diff line number Diff line
@@ -4089,7 +4089,6 @@ xfs_bmap_read_extents( 
		xfs_extnum_t	num_recs;

		xfs_extnum_t	start;





		num_recs = xfs_btree_get_numrecs(block);

		if (unlikely(i + num_recs > room)) {

			ASSERT(i + num_recs <= room);
@@ -4746,6 +4745,69 @@ xfs_bmapi_allocate( 
	return 0;

}



STATIC int

xfs_bmapi_convert_unwritten(

	struct xfs_bmalloca	*bma,

	struct xfs_bmbt_irec	*mval,

	xfs_filblks_t		len,

	xfs_extnum_t		*lastx,

	struct xfs_btree_cur	**cur,

	xfs_fsblock_t		*firstblock,

	struct xfs_bmap_free	*flist,

	int			flags,

	int			*logflags)

{

	int			whichfork = (flags & XFS_BMAPI_ATTRFORK) ?

						XFS_ATTR_FORK : XFS_DATA_FORK;

	struct xfs_ifork	*ifp = XFS_IFORK_PTR(bma->ip, whichfork);

	int			error;



	*logflags = 0;



	/* check if we need to do unwritten->real conversion */

	if (mval->br_state == XFS_EXT_UNWRITTEN &&

	    (flags & XFS_BMAPI_PREALLOC))

		return 0;



	/* check if we need to do real->unwritten conversion */

	if (mval->br_state == XFS_EXT_NORM &&

	    (flags & (XFS_BMAPI_PREALLOC | XFS_BMAPI_CONVERT)) !=

			(XFS_BMAPI_PREALLOC | XFS_BMAPI_CONVERT))

		return 0;



	/*

	 * Modify (by adding) the state flag, if writing.

	 */

	ASSERT(mval->br_blockcount <= len);

	if ((ifp->if_flags & XFS_IFBROOT) && !*cur) {

		*cur = xfs_bmbt_init_cursor(bma->ip->i_mount, bma->tp,

					bma->ip, whichfork);

		(*cur)->bc_private.b.firstblock = *firstblock;

		(*cur)->bc_private.b.flist = flist;

	}

	mval->br_state = (mval->br_state == XFS_EXT_UNWRITTEN)

				? XFS_EXT_NORM : XFS_EXT_UNWRITTEN;



	error = xfs_bmap_add_extent(bma->tp, bma->ip, lastx, cur, mval,

				firstblock, flist, logflags, whichfork);

	if (error)

		return error;



	/*

	 * Update our extent pointer, given that xfs_bmap_add_extent  might

	 * have merged it into one of the neighbouring ones.

	 */

	xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx), bma->gotp);



	/*

	 * We may have combined previously unwritten space with written space,

	 * so generate another request.

	 */

	if (mval->br_blockcount < len)

		return EAGAIN;

	return 0;

}



/*

 * Map file blocks to filesystem blocks.

 * File range is given by the bno/len pair.
@@ -4932,45 +4994,16 @@ xfs_bmapi( 
		/* Deal with the allocated space we found.  */

		xfs_bmapi_trim_map(mval, &got, &bno, len, obno, end, n, flags);



		/*

		 * Check if writing previously allocated but

		 * unwritten extents.

		 */

		if (wr &&

		    ((mval->br_state == XFS_EXT_UNWRITTEN &&

		      ((flags & XFS_BMAPI_PREALLOC) == 0)) ||

		     (mval->br_state == XFS_EXT_NORM &&

		      ((flags & (XFS_BMAPI_PREALLOC|XFS_BMAPI_CONVERT)) ==

				(XFS_BMAPI_PREALLOC|XFS_BMAPI_CONVERT))))) {

			/*

			 * Modify (by adding) the state flag, if writing.

			 */

			ASSERT(mval->br_blockcount <= len);

			if ((ifp->if_flags & XFS_IFBROOT) && !cur) {

				cur = xfs_bmbt_init_cursor(mp,

					tp, ip, whichfork);

				cur->bc_private.b.firstblock =

					*firstblock;

				cur->bc_private.b.flist = flist;

			}

			mval->br_state = (mval->br_state == XFS_EXT_UNWRITTEN)

						? XFS_EXT_NORM

						: XFS_EXT_UNWRITTEN;

			error = xfs_bmap_add_extent(tp, ip, &lastx, &cur, mval,

				firstblock, flist, &tmp_logflags,

				whichfork);

		/* Execute unwritten extent conversion if necessary */

		if (wr) {

			error = xfs_bmapi_convert_unwritten(&bma, mval, len,

						&lastx, &cur, firstblock, flist, flags,

						&tmp_logflags);

			logflags |= tmp_logflags;

			if (error == EAGAIN)

				continue;

			if (error)

				goto error0;

			ep = xfs_iext_get_ext(ifp, lastx);

			xfs_bmbt_get_all(ep, &got);

			/*

			 * We may have combined previously unwritten

			 * space with written space, so generate

			 * another request.

			 */

			if (mval->br_blockcount < len)

				continue;

		}



		/* update the extent map to return */