[PATCH v3 09/10] ext4: make ext4_insert_delayed_block() insert multi-blocks

[Zhang Yi <yi.zhang@xxxxxxxxxxxxxxx>]

From: Zhang Yi <yi.zhang@xxxxxxxxxx>

Rename ext4_insert_delayed_block() to ext4_insert_delayed_blocks(),
pass length parameter to make it insert multiple delalloc blocks at a
time. For non-bigalloc case, just reserve len blocks and insert delalloc
extent. For bigalloc case, we can ensure that the clusters in the middle
of a extent must be unallocated, we only need to check whether the start
and end clusters are delayed/allocated. We should subtract the space for
the start and/or end block(s) if they are allocated.

Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
 fs/ext4/inode.c | 48 ++++++++++++++++++++++++++++++++++--------------
 1 file changed, 34 insertions(+), 14 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 6e418d3f8e87..c56386d1b10d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1678,24 +1678,29 @@ static int ext4_da_check_clu_allocated(struct inode *inode, ext4_lblk_t lblk,
 }
 
 /*
- * ext4_insert_delayed_block - adds a delayed block to the extents status
- *                             tree, incrementing the reserved cluster/block
- *                             count or making a pending reservation
- *                             where needed
+ * ext4_insert_delayed_blocks - adds a multiple delayed blocks to the extents
+ *                              status tree, incrementing the reserved
+ *                              cluster/block count or making pending
+ *                              reservations where needed
  *
  * @inode - file containing the newly added block
- * @lblk - logical block to be added
+ * @lblk - start logical block to be added
+ * @len - length of blocks to be added
  *
  * Returns 0 on success, negative error code on failure.
  */
-static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
+static int ext4_insert_delayed_blocks(struct inode *inode, ext4_lblk_t lblk,
+				      ext4_lblk_t len)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	int ret;
-	bool allocated = false;
+	bool lclu_allocated = false;
+	bool end_allocated = false;
+	ext4_lblk_t resv_clu;
+	ext4_lblk_t end = lblk + len - 1;
 
 	/*
-	 * If the cluster containing lblk is shared with a delayed,
+	 * If the cluster containing lblk or end is shared with a delayed,
 	 * written, or unwritten extent in a bigalloc file system, it's
 	 * already been accounted for and does not need to be reserved.
 	 * A pending reservation must be made for the cluster if it's
@@ -1706,21 +1711,36 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
 	 * extents status tree doesn't get a match.
 	 */
 	if (sbi->s_cluster_ratio == 1) {
-		ret = ext4_da_reserve_space(inode, 1);
+		ret = ext4_da_reserve_space(inode, len);
 		if (ret != 0)   /* ENOSPC */
 			return ret;
 	} else {   /* bigalloc */
-		ret = ext4_da_check_clu_allocated(inode, lblk, &allocated);
+		resv_clu = EXT4_B2C(sbi, end) - EXT4_B2C(sbi, lblk) + 1;
+
+		ret = ext4_da_check_clu_allocated(inode, lblk, &lclu_allocated);
 		if (ret < 0)
 			return ret;
-		if (ret > 0) {
-			ret = ext4_da_reserve_space(inode, 1);
+		if (ret == 0)
+			resv_clu--;
+
+		if (EXT4_B2C(sbi, lblk) != EXT4_B2C(sbi, end)) {
+			ret = ext4_da_check_clu_allocated(inode, end,
+							  &end_allocated);
+			if (ret < 0)
+				return ret;
+			if (ret == 0)
+				resv_clu--;
+		}
+
+		if (resv_clu) {
+			ret = ext4_da_reserve_space(inode, resv_clu);
 			if (ret != 0)   /* ENOSPC */
 				return ret;
 		}
 	}
 
-	ext4_es_insert_delayed_extent(inode, lblk, 1, allocated, false);
+	ext4_es_insert_delayed_extent(inode, lblk, len, lclu_allocated,
+				      end_allocated);
 	return 0;
 }
 
@@ -1825,7 +1845,7 @@ static int ext4_da_map_blocks(struct inode *inode, struct ext4_map_blocks *map,
 		}
 	}
 
-	retval = ext4_insert_delayed_block(inode, map->m_lblk);
+	retval = ext4_insert_delayed_blocks(inode, map->m_lblk, map->m_len);
 	up_write(&EXT4_I(inode)->i_data_sem);
 	if (retval)
 		return retval;
-- 
2.39.2