Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Content-Type: text/plain; charset="UTF-8"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Joe Habermann" <joe.habermann@quantum.com>,
        "Lukas Czerner" <lczerner@redhat.com>,
        "Theodore Ts'o" <tytso@mit.edu>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.225827293@decadent.org.uk>
Subject: [PATCH 3.16 043/366] ext4: update mtime in ext4_punch_hole even
 if no blocks are released
In-Reply-To: <lsq.1541965744.387173642@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Lukas Czerner <lczerner@redhat.com>

commit eee597ac931305eff3d3fd1d61d6aae553bc0984 upstream.

Currently in ext4_punch_hole we're going to skip the mtime update if
there are no actual blocks to release. However we've actually modified
the file by zeroing the partial block so the mtime should be updated.

Moreover the sync and datasync handling is skipped as well, which is
also wrong. Fix it.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Joe Habermann <joe.habermann@quantum.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 fs/ext4/inode.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3749,28 +3749,28 @@ int ext4_punch_hole(struct inode *inode,
 		EXT4_BLOCK_SIZE_BITS(sb);
 	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
 
-	/* If there are no blocks to remove, return now */
-	if (first_block >= stop_block)
-		goto out_stop;
-
-	down_write(&EXT4_I(inode)->i_data_sem);
-	ext4_discard_preallocations(inode);
-
-	ret = ext4_es_remove_extent(inode, first_block,
-				    stop_block - first_block);
-	if (ret) {
-		up_write(&EXT4_I(inode)->i_data_sem);
-		goto out_stop;
-	}
+	/* If there are blocks to remove, do it */
+	if (stop_block > first_block) {
+
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ext4_discard_preallocations(inode);
 
-	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-		ret = ext4_ext_remove_space(inode, first_block,
-					    stop_block - 1);
-	else
-		ret = ext4_ind_remove_space(handle, inode, first_block,
-					    stop_block);
+		ret = ext4_es_remove_extent(inode, first_block,
+					    stop_block - first_block);
+		if (ret) {
+			up_write(&EXT4_I(inode)->i_data_sem);
+			goto out_stop;
+		}
+
+		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+			ret = ext4_ext_remove_space(inode, first_block,
+						    stop_block - 1);
+		else
+			ret = ext4_ind_remove_space(handle, inode, first_block,
+						    stop_block);
 
-	up_write(&EXT4_I(inode)->i_data_sem);
+		up_write(&EXT4_I(inode)->i_data_sem);
+	}
 	if (IS_SYNC(inode))
 		ext4_handle_sync(handle);