From 02c6db4f7308e4f5adf4df2ef623160bfdb18636 Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Wed, 20 Mar 2019 14:27:45 +0800
Patch-mainline: v5.2
Git-commit: 02c6db4f7308e4f5adf4df2ef623160bfdb18636
References: bsc#1168273
Subject: [PATCH 5/7] btrfs: extent_io: Handle errors better in
 extent_write_locked_range()

We can only get @ret <= 0.  Add an ASSERT() for it just in case.

Then, instead of submitting the write bio even we got some error, check
the return value first.

If we have already hit some error, just clean up the corrupted or
half-baked bio, and return error.

If there is no error so far, then call flush_write_bio() and return the
result.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/extent_io.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index cd76be7013d8..b43a0a0f41e4 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4042,7 +4042,6 @@ int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
 			      int mode)
 {
 	int ret = 0;
-	int flush_ret;
 	struct address_space *mapping = inode->i_mapping;
 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 	struct page *page;
@@ -4075,8 +4074,12 @@ int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
 		start += PAGE_SIZE;
 	}
 
-	flush_ret = flush_write_bio(&epd);
-	BUG_ON(flush_ret < 0);
+	ASSERT(ret <= 0);
+	if (ret < 0) {
+		end_write_bio(&epd, ret);
+		return ret;
+	}
+	ret = flush_write_bio(&epd);
 	return ret;
 }
 
-- 
2.26.0