From eee597ac931305eff3d3fd1d61d6aae553bc0984 Mon Sep 17 00:00:00 2001
From: Lukas Czerner <lczerner@redhat.com>
Date: Sun, 13 May 2018 19:28:35 -0400
Subject: [PATCH] ext4: update mtime in ext4_punch_hole even if no blocks are
 released
Git-commit: eee597ac931305eff3d3fd1d61d6aae553bc0984
Patch-mainline: v4.18-rc1
References: bsc#1101895

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>
Cc: <stable@vger.kernel.org>
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/ext4/inode.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9d512fa80d28..58301a697379 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4298,28 +4298,28 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
 		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;
+	/* 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);
+		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;
-	}
+		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);
+		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);
 
-- 
2.16.4