On 2019/11/11 6:03 PM, Qu Wenruo wrote:
On 2019/11/11 下午5:49, Su Yue wrote:
On 2019/11/11 5:28 PM, Qu Wenruo wrote:
On 2019/11/11 下午4:42, damenly.su@xxxxxxxxx wrote:
From: Su Yue <Damenly_Su@xxxxxxx>
The progs side function btrfs_lookup_first_block_group() calls
find_first_extent_bit() to find block group which contains bytenr
or after the bytenr. This behavior differs from kernel code, so
add the comments.
Add the coments of btrfs_lookup_block_group() too, this one works
like kernel side.
Signed-off-by: Su Yue <Damenly_Su@xxxxxxx>
---
extent-tree.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/extent-tree.c b/extent-tree.c
index d67e4098351f..f690ae999f37 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -164,6 +164,9 @@ err:
return 0;
}
+/*
+ * Return the block group that contains or after bytenr
+ */
What about "Return the block group thart starts at or after @bytenr" ?
That's what documented in kernel already.
The thing I try to express is "contains".
For such a block group marked as B[n, m).
btrfs_lookup_first_block_group(x) (x > n && x < m). Kernel code will
return the block group next to B. However, progs side will return the
block group B.
"Contains" indeed covers your example.
But the "after @bytenr" part looks strange to me.
Did you mean if @bytenr is not covered by any block group, then the next
block group starts after @bytenr is returned?
Yes, that's precisely what I mean.
Thanks.
Then the comment is good.
Thanks,
Qu
Thanks.
Thanks,
Qu
struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
btrfs_fs_info *info,
u64 bytenr)
@@ -193,6 +196,9 @@ struct btrfs_block_group_cache
*btrfs_lookup_first_block_group(struct
return block_group;
}
+/*
+ * Return the block group that contains the given bytenr
+ */
struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
btrfs_fs_info *info,
u64 bytenr)
