linux-ext4 - [PATCH v3 4/4] ext4: convert ext4_split_extent() to return requested length

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Date:   Fri, 25 Jan 2019 20:30:56 +0800
From:   "zhangyi (F)" <yi.zhang@...wei.com>
To:     <linux-ext4@...r.kernel.org>
CC:     <tytso@....edu>, <jack@...e.cz>, <adilger.kernel@...ger.ca>,
        <yi.zhang@...wei.com>, <miaoxie@...wei.com>
Subject: [PATCH v3 4/4] ext4: convert ext4_split_extent() to return requested length

After we remove clean_bdev_aliases() calls which used to unmap extra
blocks in ext4_ext_handle_unwritten_extents(), return extra initialized
region in ext4_ext_convert_to_initialized() is no longer needed, so
in order to simplify logic, this patch convert to return the requested
size instead.

Signed-off-by: zhangyi (F) <yi.zhang@...wei.com>
---
 fs/ext4/extents.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ffb72d8..ffe9671 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3456,9 +3456,8 @@ static int ext4_split_extent(handle_t *handle,
  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
  *
  * Post-conditions on success:
- *  - the returned value is the number of blocks beyond map->l_lblk
- *    that are allocated and initialized.
- *    It is guaranteed to be >= map->m_len.
+ *  - The returned value is the minimum number of requested blocks or
+ *    initialized blocks. It is guaranteed to be <= map->m_len.
  */
 static int ext4_ext_convert_to_initialized(handle_t *handle,
 					   struct inode *inode,
@@ -3700,7 +3699,6 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 
 			split_map.m_len += split_map.m_lblk - ee_block;
 			split_map.m_lblk = ee_block;
-			allocated = map->m_len;
 		}
 	}
 
@@ -3709,6 +3707,9 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 	if (err > 0)
 		err = 0;
 out:
+	if (allocated > map->m_len)
+		allocated = map->m_len;
+
 	/* If we have gotten a failure, don't zero out status tree */
 	if (!err) {
 		err = ext4_zeroout_es(inode, &zero_ex1);
@@ -4065,11 +4066,10 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
 	if (ret <= 0) {
 		err = ret;
 		goto out2;
-	} else
-		allocated = ret;
+	}
+
+	allocated = ret;
 	map->m_flags |= EXT4_MAP_NEW;
-	if (allocated > map->m_len)
-		allocated = map->m_len;
 	map->m_len = allocated;
 
 map_out:
-- 
2.7.4