linux-kernel - [PATCH] ext4: fix fast commit may miss tracking range for FALLOC_FL_ZERO

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Message-Id: <20211201095258.1966-1-yinxin.x@bytedance.com>
Date:   Wed,  1 Dec 2021 17:52:58 +0800
From:   Xin Yin <yinxin.x@...edance.com>
To:     harshadshirwadkar@...il.com, tytso@....edu,
        adilger.kernel@...ger.ca
Cc:     linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
        Xin Yin <yinxin.x@...edance.com>
Subject: [PATCH] ext4: fix fast commit may miss tracking range for FALLOC_FL_ZERO_RANGE

when call falloc with FALLOC_FL_ZERO_RANGE, to set an range to unwritten,
which has been already initialized. If the range is align to blocksize,
fast commit will not track range for this change.

change to track range during allocating blocks.

Signed-off-by: Xin Yin <yinxin.x@...edance.com>
---
 fs/ext4/extents.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9229ab1f99c5..4108896d471b 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4433,6 +4433,8 @@ static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
 			ret2 = ext4_journal_stop(handle);
 			break;
 		}
+		ext4_fc_track_range(handle, inode, map.m_lblk,
+					map.m_lblk + map.m_len - 1);
 		map.m_lblk += ret;
 		map.m_len = len = len - ret;
 		epos = (loff_t)map.m_lblk << inode->i_blkbits;
@@ -4599,8 +4601,6 @@ static long ext4_zero_range(struct file *file, loff_t offset,
 	ret = ext4_mark_inode_dirty(handle, inode);
 	if (unlikely(ret))
 		goto out_handle;
-	ext4_fc_track_range(handle, inode, offset >> inode->i_sb->s_blocksize_bits,
-			(offset + len - 1) >> inode->i_sb->s_blocksize_bits);
 	/* Zero out partial block at the edges of the range */
 	ret = ext4_zero_partial_blocks(handle, inode, offset, len);
 	if (ret >= 0)
-- 
2.20.1