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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xin Yin <yinxin.x@bytedance.com>,
        Harshad Shirwadkar <harshadshirwadkar@gmail.com>,
        Theodore Tso <tytso@mit.edu>, stable@kernel.org
Subject: [PATCH 5.15 717/846] ext4: fix fast commit may miss tracking range for FALLOC_FL_ZERO_RANGE
Date:   Mon, 24 Jan 2022 19:43:54 +0100
Message-Id: <20220124184125.755716147@linuxfoundation.org>
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From: Xin Yin <yinxin.x@bytedance.com>

commit 5e4d0eba1ccaf19f93222abdeda5a368be141785 upstream.

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.

Also track range for unwritten range in ext4_map_blocks().

Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211221022839.374606-1-yinxin.x@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/ext4/extents.c |    2 --
 fs/ext4/inode.c   |    7 ++++---
 2 files changed, 4 insertions(+), 5 deletions(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4645,8 +4645,6 @@ static long ext4_zero_range(struct file
 	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)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -741,10 +741,11 @@ out_sem:
 			if (ret)
 				return ret;
 		}
-		ext4_fc_track_range(handle, inode, map->m_lblk,
-			    map->m_lblk + map->m_len - 1);
 	}
-
+	if (retval > 0 && (map->m_flags & EXT4_MAP_UNWRITTEN ||
+				map->m_flags & EXT4_MAP_MAPPED))
+		ext4_fc_track_range(handle, inode, map->m_lblk,
+					map->m_lblk + map->m_len - 1);
 	if (retval < 0)
 		ext_debug(inode, "failed with err %d\n", retval);
 	return retval;