[PATCH 02/10] xfs: rewrite xfs_da_grow_inode_int

[Christoph Hellwig <hch@lst.de>]

Use one xfs_bmapi_write loop that just iterates if it didn't manage to
allocate enough blocks.  Get rid of the separate contig call that just
makes us call the allocator twice, and also get rid of the memory
allocation for the map array that we don't actually need.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_da_btree.c | 94 +++++++++++++-------------------------------
 1 file changed, 28 insertions(+), 66 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
index 1bdf2888295b..00853d332bcd 100644
--- a/fs/xfs/libxfs/xfs_da_btree.c
+++ b/fs/xfs/libxfs/xfs_da_btree.c
@@ -2007,84 +2007,46 @@ xfs_da_grow_inode_int(
 	xfs_fileoff_t		*bno,
 	int			count)
 {
-	struct xfs_trans	*tp = args->trans;
-	struct xfs_inode	*dp = args->dp;
 	int			w = args->whichfork;
-	xfs_rfsblock_t		nblks = dp->i_d.di_nblocks;
-	struct xfs_bmbt_irec	map, *mapp;
-	int			nmap, error, got, i, mapi;
+	xfs_fileoff_t		b;
+	int			error;
 
 	/*
 	 * Find a spot in the file space to put the new block.
 	 */
-	error = xfs_bmap_first_unused(tp, dp, count, bno, w);
+	error = xfs_bmap_first_unused(args->trans, args->dp, count, bno, w);
 	if (error)
 		return error;
 
-	/*
-	 * Try mapping it in one filesystem block.
-	 */
-	nmap = 1;
-	ASSERT(args->firstblock != NULL);
-	error = xfs_bmapi_write(tp, dp, *bno, count,
-			xfs_bmapi_aflag(w)|XFS_BMAPI_METADATA|XFS_BMAPI_CONTIG,
-			args->firstblock, args->total, &map, &nmap,
-			args->dfops);
-	if (error)
-		return error;
+	b = *bno;
+	do {
+		xfs_rfsblock_t nblks = args->dp->i_d.di_nblocks;
+		struct xfs_bmbt_irec imap;
+		xfs_extlen_t len;
+		int nmap = 1;
+
+		error = xfs_bmapi_write(args->trans, args->dp, b, count,
+				xfs_bmapi_aflag(w) | XFS_BMAPI_METADATA,
+				args->firstblock, args->total, &imap, &nmap,
+				args->dfops);
+		if (error)
+			return error;
+		if (!nmap)
+			return -ENOSPC;
 
-	ASSERT(nmap <= 1);
-	if (nmap == 1) {
-		mapp = &map;
-		mapi = 1;
-	} else if (nmap == 0 && count > 1) {
-		xfs_fileoff_t		b;
-		int			c;
+		len = imap.br_startoff + imap.br_blockcount - b;
+		ASSERT(imap.br_startoff <= b);
+		ASSERT(len > 0);
+		ASSERT(len <= count);
 
-		/*
-		 * If we didn't get it and the block might work if fragmented,
-		 * try without the CONTIG flag.  Loop until we get it all.
-		 */
-		mapp = kmem_alloc(sizeof(*mapp) * count, KM_SLEEP);
-		for (b = *bno, mapi = 0; b < *bno + count; ) {
-			nmap = MIN(XFS_BMAP_MAX_NMAP, count);
-			c = (int)(*bno + count - b);
-			error = xfs_bmapi_write(tp, dp, b, c,
-					xfs_bmapi_aflag(w)|XFS_BMAPI_METADATA,
-					args->firstblock, args->total,
-					&mapp[mapi], &nmap, args->dfops);
-			if (error)
-				goto out_free_map;
-			if (nmap < 1)
-				break;
-			mapi += nmap;
-			b = mapp[mapi - 1].br_startoff +
-			    mapp[mapi - 1].br_blockcount;
-		}
-	} else {
-		mapi = 0;
-		mapp = NULL;
-	}
-
-	/*
-	 * Count the blocks we got, make sure it matches the total.
-	 */
-	for (i = 0, got = 0; i < mapi; i++)
-		got += mapp[i].br_blockcount;
-	if (got != count || mapp[0].br_startoff != *bno ||
-	    mapp[mapi - 1].br_startoff + mapp[mapi - 1].br_blockcount !=
-	    *bno + count) {
-		error = -ENOSPC;
-		goto out_free_map;
-	}
+		/* account for newly allocated blocks in reserved blocks total */
+		args->total -= (args->dp->i_d.di_nblocks - nblks);
 
-	/* account for newly allocated blocks in reserved blocks total */
-	args->total -= dp->i_d.di_nblocks - nblks;
+		b += len;
+		count -= len;
+	} while (count > 0);
 
-out_free_map:
-	if (mapp != &map)
-		kmem_free(mapp);
-	return error;
+	return 0;
 }
 
 /*
-- 
2.11.0