btrfs: btrfs_wait_tree_block_writeback can be void return

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>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index bfeb5c12e3ff9e741612a8f5099adcf12e5bb7d1..cdc28ad7f1ed3a9efe7d6da3ab05edb22ffb2946 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1223,10 +1223,10 @@ 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,
-                                      buf->start, buf->start + buf->len - 1);
+       filemap_fdatawait_range(buf->pages[0]->mapping,
+                               buf->start, buf->start + buf->len - 1);
 }
 
 struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 35ddfcf04ad058cf21d763b0aae4937e9d331530..4654d129aa7621e389602b19ccdf79ed899077b3 100644 (file)
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -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,