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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 5.15 721/846] ext4: fast commit may miss tracking unwritten range during ftruncate
Date:   Mon, 24 Jan 2022 19:43:58 +0100
Message-Id: <20220124184125.887304707@linuxfoundation.org>
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From: Xin Yin <yinxin.x@bytedance.com>

commit 9725958bb75cdfa10f2ec11526fdb23e7485e8e4 upstream.

If use FALLOC_FL_KEEP_SIZE to alloc unwritten range at bottom, the
inode->i_size will not include the unwritten range. When call
ftruncate with fast commit enabled, it will miss to track the
unwritten range.

Change to trace the full range during ftruncate.

Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223032337.5198-3-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/inode.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5414,8 +5414,7 @@ int ext4_setattr(struct user_namespace *
 				ext4_fc_track_range(handle, inode,
 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
 					inode->i_sb->s_blocksize_bits,
-					(oldsize > 0 ? oldsize - 1 : 0) >>
-					inode->i_sb->s_blocksize_bits);
+					EXT_MAX_BLOCKS - 1);
 			else
 				ext4_fc_track_range(
 					handle, inode,