linux-kernel - [PATCH 5.0 003/346] ext4: wait for outstanding dio during truncate in nojournal mode

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Message-Id: <20190530030540.580600723@linuxfoundation.org>
Date:   Wed, 29 May 2019 20:01:16 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ira Weiny <ira.weiny@...el.com>,
        Jan Kara <jack@...e.cz>, Theodore Tso <tytso@....edu>
Subject: [PATCH 5.0 003/346] ext4: wait for outstanding dio during truncate in nojournal mode

From: Jan Kara <jack@...e.cz>

commit 82a25b027ca48d7ef197295846b352345853dfa8 upstream.

We didn't wait for outstanding direct IO during truncate in nojournal
mode (as we skip orphan handling in that case). This can lead to fs
corruption or stale data exposure if truncate ends up freeing blocks
and these get reallocated before direct IO finishes. Fix the condition
determining whether the wait is necessary.

CC: stable@...r.kernel.org
Fixes: 1c9114f9c0f1 ("ext4: serialize unlocked dio reads with truncate")
Reviewed-by: Ira Weiny <ira.weiny@...el.com>
Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Theodore Ts'o <tytso@....edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/ext4/inode.c |   21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5632,20 +5632,17 @@ int ext4_setattr(struct dentry *dentry,
 				goto err_out;
 			}
 		}
-		if (!shrink)
+		if (!shrink) {
 			pagecache_isize_extended(inode, oldsize, inode->i_size);
-
-		/*
-		 * Blocks are going to be removed from the inode. Wait
-		 * for dio in flight.  Temporarily disable
-		 * dioread_nolock to prevent livelock.
-		 */
-		if (orphan) {
-			if (!ext4_should_journal_data(inode)) {
-				inode_dio_wait(inode);
-			} else
-				ext4_wait_for_tail_page_commit(inode);
+		} else {
+			/*
+			 * Blocks are going to be removed from the inode. Wait
+			 * for dio in flight.
+			 */
+			inode_dio_wait(inode);
 		}
+		if (orphan && ext4_should_journal_data(inode))
+			ext4_wait_for_tail_page_commit(inode);
 		down_write(&EXT4_I(inode)->i_mmap_sem);
 
 		rc = ext4_break_layouts(inode);