From 2ded6409b3a22e68c19236153f0456e1c079d0da Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@redhat.com>
Date: Tue, 20 Dec 2016 09:23:29 -0600
Subject: [PATCH] libext2fs: don't ignore fsync errors

Today, if mke2fs experiences IO errors (say, on a thin device
which filled up during mkfs), mke2fs is silent and returns
success even though the filesystem was not properly created.

Catch errors from the io_channel_flush() callchain to
fix this up.  Fix formatting of the printed error as
well:

...
Creating journal (262144 blocks): done
Writing superblocks and filesystem accounting information:
Warning, had trouble writing out superblocks.
# echo $?
5

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 lib/ext2fs/closefs.c | 10 ++++++++--
 lib/ext2fs/unix_io.c |  3 ++-
 misc/mke2fs.c        |  2 +-
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/ext2fs/closefs.c b/lib/ext2fs/closefs.c
index a73c53f..000ebd8 100644
--- a/lib/ext2fs/closefs.c
+++ b/lib/ext2fs/closefs.c
@@ -410,16 +410,22 @@ write_primary_superblock_only:
 	ext2fs_swap_super(super_shadow);
 #endif
 
-	if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
+	if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC)) {
 		retval = io_channel_flush(fs->io);
+		if (retval)
+			goto errout;
+	}
 	retval = write_primary_superblock(fs, super_shadow);
 	if (retval)
 		goto errout;
 
 	fs->flags &= ~EXT2_FLAG_DIRTY;
 
-	if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
+	if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC)) {
 		retval = io_channel_flush(fs->io);
+		if (retval)
+			goto errout;
+	}
 errout:
 	fs->super->s_state = fs_state;
 #ifdef WORDS_BIGENDIAN
diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
index 19be630..a2069f0 100644
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -885,7 +885,8 @@ static errcode_t unix_flush(io_channel channel)
 #ifndef NO_IO_CACHE
 	retval = flush_cached_blocks(channel, data, 0);
 #endif
-	fsync(data->dev);
+	if (!retval && fsync(data->dev) != 0)
+		return errno;
 	return retval;
 }
 
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index 3e3ef95..8952a5f 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -2764,7 +2764,7 @@ no_journal:
 	retval = ext2fs_close(fs);
 	if (retval) {
 		fprintf(stderr, "%s",
-			_("\nWarning, had trouble writing out superblocks."));
+			_("\nWarning, had trouble writing out superblocks.\n"));
 	} else if (!quiet) {
 		printf("%s", _("done\n\n"));
 		if (!getenv("MKE2FS_SKIP_CHECK_MSG"))
-- 
2.7.4