linux-kernel - [PATCH v2 01/13] ext4: cleanup zeroout in ext4_split_extent

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Message-ID: <20251121060811.1685783-2-yi.zhang@huaweicloud.com>
Date: Fri, 21 Nov 2025 14:07:59 +0800
From: Zhang Yi <yi.zhang@...weicloud.com>
To: linux-ext4@...r.kernel.org
Cc: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	tytso@....edu,
	adilger.kernel@...ger.ca,
	jack@...e.cz,
	yi.zhang@...wei.com,
	yi.zhang@...weicloud.com,
	yizhang089@...il.com,
	libaokun1@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH v2 01/13] ext4: cleanup zeroout in ext4_split_extent_at()

From: Zhang Yi <yi.zhang@...wei.com>

zero_ex is a temporary variable used only for writing zeros and
inserting extent status entry, it will not be directly inserted into the
tree. Therefore, it can be assigned values from the target extent in
various scenarios, eliminating the need to explicitly assign values to
each variable individually.

Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/ext4/extents.c | 63 ++++++++++++++++++-----------------------------
 1 file changed, 24 insertions(+), 39 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index c7d219e6c6d8..91682966597d 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3278,46 +3278,31 @@ static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,
 	ex = path[depth].p_ext;
 
 	if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
-		if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
-			if (split_flag & EXT4_EXT_DATA_VALID1) {
-				err = ext4_ext_zeroout(inode, ex2);
-				zero_ex.ee_block = ex2->ee_block;
-				zero_ex.ee_len = cpu_to_le16(
-						ext4_ext_get_actual_len(ex2));
-				ext4_ext_store_pblock(&zero_ex,
-						      ext4_ext_pblock(ex2));
-			} else {
-				err = ext4_ext_zeroout(inode, ex);
-				zero_ex.ee_block = ex->ee_block;
-				zero_ex.ee_len = cpu_to_le16(
-						ext4_ext_get_actual_len(ex));
-				ext4_ext_store_pblock(&zero_ex,
-						      ext4_ext_pblock(ex));
-			}
-		} else {
-			err = ext4_ext_zeroout(inode, &orig_ex);
-			zero_ex.ee_block = orig_ex.ee_block;
-			zero_ex.ee_len = cpu_to_le16(
-						ext4_ext_get_actual_len(&orig_ex));
-			ext4_ext_store_pblock(&zero_ex,
-					      ext4_ext_pblock(&orig_ex));
-		}
+		if (split_flag & EXT4_EXT_DATA_VALID1)
+			memcpy(&zero_ex, ex2, sizeof(zero_ex));
+		else if (split_flag & EXT4_EXT_DATA_VALID2)
+			memcpy(&zero_ex, ex, sizeof(zero_ex));
+		else
+			memcpy(&zero_ex, &orig_ex, sizeof(zero_ex));
 
-		if (!err) {
-			/* update the extent length and mark as initialized */
-			ex->ee_len = cpu_to_le16(ee_len);
-			ext4_ext_try_to_merge(handle, inode, path, ex);
-			err = ext4_ext_dirty(handle, inode, path + path->p_depth);
-			if (!err)
-				/* update extent status tree */
-				ext4_zeroout_es(inode, &zero_ex);
-			/* If we failed at this point, we don't know in which
-			 * state the extent tree exactly is so don't try to fix
-			 * length of the original extent as it may do even more
-			 * damage.
-			 */
-			goto out;
-		}
+		err = ext4_ext_zeroout(inode, &zero_ex);
+		if (err)
+			goto fix_extent_len;
+
+		/* update the extent length and mark as initialized */
+		ex->ee_len = cpu_to_le16(ee_len);
+		ext4_ext_try_to_merge(handle, inode, path, ex);
+		err = ext4_ext_dirty(handle, inode, path + path->p_depth);
+		if (!err)
+			/* update extent status tree */
+			ext4_zeroout_es(inode, &zero_ex);
+		/*
+		 * If we failed at this point, we don't know in which
+		 * state the extent tree exactly is so don't try to fix
+		 * length of the original extent as it may do even more
+		 * damage.
+		 */
+		goto out;
 	}
 
 fix_extent_len:
-- 
2.46.1