linux-kernel - [PATCH v2 2/4] ext4: fix incorrect punch max

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Message-ID: <20250506012009.3896990-2-yi.zhang@huaweicloud.com>
Date: Tue,  6 May 2025 09:20:07 +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,
	wanghaichi0403@...il.com,
	yi.zhang@...wei.com,
	yi.zhang@...weicloud.com,
	libaokun1@...wei.com,
	yukuai3@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH v2 2/4] ext4: fix incorrect punch max_end

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

For the extents based inodes, the maxbytes should be sb->s_maxbytes
instead of sbi->s_bitmap_maxbytes. Additionally, for the calculation of
max_end, the -sb->s_blocksize operation is necessary only for
indirect-block based inodes. Correct the maxbytes and max_end value to
correct the behavior of punch hole.

Fixes: 2da376228a24 ("ext4: limit length to bitmap_maxbytes - blocksize in punch_hole")
Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/ext4/inode.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4ec4a80b6879..5691966a19e1 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4006,7 +4006,7 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 	struct inode *inode = file_inode(file);
 	struct super_block *sb = inode->i_sb;
 	ext4_lblk_t start_lblk, end_lblk;
-	loff_t max_end = EXT4_SB(sb)->s_bitmap_maxbytes - sb->s_blocksize;
+	loff_t max_end = sb->s_maxbytes;
 	loff_t end = offset + length;
 	handle_t *handle;
 	unsigned int credits;
@@ -4015,14 +4015,20 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 	trace_ext4_punch_hole(inode, offset, length, 0);
 	WARN_ON_ONCE(!inode_is_locked(inode));
 
+	/*
+	 * For indirect-block based inodes, make sure that the hole within
+	 * one block before last range.
+	 */
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		max_end = EXT4_SB(sb)->s_bitmap_maxbytes - sb->s_blocksize;
+
 	/* No need to punch hole beyond i_size */
 	if (offset >= inode->i_size || offset >= max_end)
 		return 0;
 
 	/*
 	 * If the hole extends beyond i_size, set the hole to end after
-	 * the page that contains i_size, and also make sure that the hole
-	 * within one block before last range.
+	 * the page that contains i_size.
 	 */
 	if (end > inode->i_size)
 		end = round_up(inode->i_size, PAGE_SIZE);
-- 
2.46.1