Commit 217f5004 authored Aug 12, 2020 by Nikolay Borisov Committed by David Sterba Oct 07, 2020

btrfs: rework error detection in init_tree_roots



To avoid duplicating 3 lines of code the error detection logic in
init_tree_roots is somewhat quirky. It first checks for the presence of
any error condition, then checks for the specific condition to perform
any specific actions. That's spurious because directly checking for
each respective error condition and doing the necessary steps is more
obvious. While at it change the -EUCLEAN to -EIO in case the extent
buffer is not read correctly, this is in line with other sites which
return -EIO when the eb couldn't be read.

Additionally it results in smaller code and the code reads
more linearly:

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-95 (-95)
Function                                     old     new   delta
open_ctree                                 17243   17148     -95
Total: Before=113104, After=113009, chg -0.08%

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent e85fde51

fs/btrfs/disk-io.c

+9 −10

Original line number	Diff line number	Diff line
		@@ -2623,18 +2623,17 @@ static int __cold init_tree_roots(struct btrfs_fs_info *fs_info)
		level = btrfs_super_root_level(sb);
		tree_root->node = read_tree_block(fs_info, btrfs_super_root(sb),
		generation, level, NULL);
		if (IS_ERR(tree_root->node) \|\|
		!extent_buffer_uptodate(tree_root->node)) {
		handle_error = true;

		if (IS_ERR(tree_root->node)) {
		handle_error = true;
		ret = PTR_ERR(tree_root->node);
		tree_root->node = NULL;
		} else if (!extent_buffer_uptodate(tree_root->node)) {
		ret = -EUCLEAN;
		}
		btrfs_warn(fs_info, "couldn't read tree root");
		continue;

		btrfs_warn(fs_info, "failed to read tree root");
		} else if (!extent_buffer_uptodate(tree_root->node)) {
		handle_error = true;
		ret = -EIO;
		btrfs_warn(fs_info, "error while reading tree root");
		continue;
		}

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