Commit b98f2b8f authored Sep 11, 2019 by Filipe Manana Committed by Greg Kroah-Hartman Nov 18, 2020

Btrfs: fix missing error return if writeback for extent buffer never started



[ Upstream commit 0607eb1d452d45c5ac4c745a9e9e0d95152ea9d0 ]

If lock_extent_buffer_for_io() fails, it returns a negative value, but its
caller btree_write_cache_pages() ignores such error. This means that a
call to flush_write_bio(), from lock_extent_buffer_for_io(), might have
failed. We should make btree_write_cache_pages() notice such error values
and stop immediatelly, making sure filemap_fdatawrite_range() returns an
error to the transaction commit path. A failure from flush_write_bio()
should also result in the endio callback end_bio_extent_buffer_writepage()
being invoked, which sets the BTRFS_FS_*_ERR bits appropriately, so that
there's no risk a transaction or log commit doesn't catch a writeback
failure.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 0982aa54

fs/btrfs/extent_io.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -3913,6 +3913,10 @@ int btree_write_cache_pages(struct address_space *mapping,
		if (!ret) {
		free_extent_buffer(eb);
		continue;
		} else if (ret < 0) {
		done = 1;
		free_extent_buffer(eb);
		break;
		}

		ret = write_one_eb(eb, fs_info, wbc, &epd);