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Commit 3065976b authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: extent_io: Handle errors better in extent_write_full_page() 



Since now flush_write_bio() could return error, kill the BUG_ON() first.
Then don't call flush_write_bio() unconditionally, instead we check the
return value from __extent_writepage() first.

If __extent_writepage() fails, we do cleanup, and return error without
submitting the possible corrupted or half-baked bio.

If __extent_writepage() successes, then we call flush_write_bio() and
return the result.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent f4340622

fs/btrfs/extent_io.c

+21 −3
Original line number Diff line number Diff line
@@ -170,6 +170,16 @@ static int __must_check submit_one_bio(struct bio *bio, int mirror_num, 
	return blk_status_to_errno(ret);

}



/* Cleanup unsubmitted bios */

static void end_write_bio(struct extent_page_data *epd, int ret)

{

	if (epd->bio) {

		epd->bio->bi_status = errno_to_blk_status(ret);

		bio_endio(epd->bio);

		epd->bio = NULL;

	}

}



/*

 * Submit bio from extent page data via submit_one_bio

 *
@@ -3397,6 +3407,9 @@ static noinline_for_stack int __extent_writepage_io(struct inode *inode, 
 * records are inserted to lock ranges in the tree, and as dirty areas

 * are found, they are marked writeback.  Then the lock bits are removed

 * and the end_io handler clears the writeback ranges

 *

 * Return 0 if everything goes well.

 * Return <0 for error.

 */

static int __extent_writepage(struct page *page, struct writeback_control *wbc,

			      struct extent_page_data *epd)
@@ -3466,6 +3479,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, 
		end_extent_writepage(page, ret, start, page_end);

	}

	unlock_page(page);

	ASSERT(ret <= 0);

	return ret;



done_unlocked:
@@ -4007,7 +4021,6 @@ static int extent_write_cache_pages(struct address_space *mapping, 
int extent_write_full_page(struct page *page, struct writeback_control *wbc)

{

	int ret;

	int flush_ret;

	struct extent_page_data epd = {

		.bio = NULL,

		.tree = &BTRFS_I(page->mapping->host)->io_tree,
@@ -4016,9 +4029,14 @@ int extent_write_full_page(struct page *page, struct writeback_control *wbc) 
	};



	ret = __extent_writepage(page, wbc, &epd);

	ASSERT(ret <= 0);

	if (ret < 0) {

		end_write_bio(&epd, ret);

		return ret;

	}



	flush_ret = flush_write_bio(&epd);

	BUG_ON(flush_ret < 0);

	ret = flush_write_bio(&epd);

	ASSERT(ret <= 0);

	return ret;

}