btrfs: btrfs_wait_tree_block_writeback can be void return (3189ff77) · Commits · 戴 / test

Nothing checks its return value. Is it safe to skip checking return value of btrfs_wait_tree_block_writeback? Liu Bo: I think yes, it's used in walk_log_tree which is called in two places, free_log_tree and log replay. For free_log_tree, it waits for any running writeback of the extent buffer under freeing to finish in case we need to access the eb pointer from page->private, and it's OK to not check the return value, while for log replay, it's doesn't wait because wc->wait is not set. So neither cares about the writeback error. Signed-off-by:

Jeff Layton <jlayton@redhat.com> Reviewed-by:

Jan Kara <jack@suse.cz> Reviewed-by:

Liu Bo <bo.li.liu@oracle.com> [ added more explanation to changelog, from Liu Bo ] Signed-off-by:

David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1223,9 +1223,9 @@ int btrfs_write_tree_block(struct extent_buffer *buf)
		buf->start + buf->len - 1);
		}

		int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
		void btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
		{
		return filemap_fdatawait_range(buf->pages[0]->mapping,
		filemap_fdatawait_range(buf->pages[0]->mapping,
		buf->start, buf->start + buf->len - 1);
		}

fs/btrfs/disk-io.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -127,7 +127,7 @@ int btrfs_wq_submit_bio(struct btrfs_fs_info fs_info, struct bio bio,
		extent_submit_bio_hook_t *submit_bio_done);
		unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info);
		int btrfs_write_tree_block(struct extent_buffer *buf);
		int btrfs_wait_tree_block_writeback(struct extent_buffer *buf);
		void btrfs_wait_tree_block_writeback(struct extent_buffer *buf);
		int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
		struct btrfs_fs_info *fs_info);
		int btrfs_add_log_tree(struct btrfs_trans_handle *trans,

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