linux-ext4 - [PATCH 6/9] ext4: correct the journal credits calculations of allocating blocks

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Message-ID: <20241125114419.903270-7-yi.zhang@huaweicloud.com>
Date: Mon, 25 Nov 2024 19:44:16 +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,
	willy@...radead.org,
	adilger.kernel@...ger.ca,
	jack@...e.cz,
	brauner@...nel.org,
	yi.zhang@...wei.com,
	yi.zhang@...weicloud.com,
	chengzhihao1@...wei.com,
	yukuai3@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH 6/9] ext4: correct the journal credits calculations of allocating blocks

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

The journal credits calculation in ext4_ext_index_trans_blocks() is
currently inadequate. It only multiplies the depth of the extents tree
and doesn't account for the blocks that may be required for adding the
leaf extents themselves.

After enabling large folios, we can easily run out of handle credits,
triggering a warning in jbd2_journal_dirty_metadata() on filesystems
with a 1KB block size. This occurs because we may need more extents when
iterating through each folio. Therefore, we should modify ext4_ext_index
trans_blocks() to include a count of the leaf extents as well.

Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/ext4/extents.c | 5 +++--
 fs/ext4/inode.c   | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 34e25eee6521..1dbcf0cb8003 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2405,9 +2405,10 @@ int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
 	depth = ext_depth(inode);
 
 	if (extents <= 1)
-		index = depth * 2;
+		index = depth * 2 + extents;
 	else
-		index = depth * 3;
+		index = depth * 3 +
+			DIV_ROUND_UP(extents, ext4_ext_space_block(inode, 0));
 
 	return index;
 }
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e7b485b0f81b..0ef41e264ee8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5687,7 +5687,7 @@ static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
 	 * Now let's see how many group bitmaps and group descriptors need
 	 * to account
 	 */
-	groups = idxblocks + pextents;
+	groups = idxblocks;
 	gdpblocks = groups;
 	if (groups > ngroups)
 		groups = ngroups;
-- 
2.46.1