In find_free_extent() under checks: tag, we have the following code
------
search_start = ALIGN(offset, fs_info->stripesize);
/* move on to the next group */
if (search_start + num_bytes >
block_group->key.objectid + block_group->key.offset) {
btrfs_add_free_space(block_group, offset, num_bytes);
goto loop;
}
if (offset < search_start)
btrfs_add_free_space(block_group, offset,
search_start - offset);
BUG_ON(offset > search_start);
------
However ALIGN() is rounding down, thus @search_start <= @offset.
That later (offset < search_start) check will never be true, but that
BUG_ON(offset > search_start) can be triggered as long as our @offset is
not aligned to @stripesize.
However we never has such report on this BUG_ON(), which means the
search result @offset is always aligned to @fs_info->stripesize (which
is also set to sector size at mkfs time), or it's handled by block group
range check.
Anyway, remove such dead unalignment check.
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
fs/btrfs/extent-tree.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f18e86177067..48a2aec7dc59 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7754,7 +7754,7 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
goto loop;
}
checks:
- search_start = ALIGN(offset, fs_info->stripesize);
+ search_start = round_down(offset, fs_info->stripesize);
/* move on to the next group */
if (search_start + num_bytes >
@@ -7763,11 +7763,6 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
goto loop;
}
- if (offset < search_start)
- btrfs_add_free_space(block_group, offset,
- search_start - offset);
- BUG_ON(offset > search_start);
-
ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
num_bytes, delalloc);
if (ret == -EAGAIN) {
--
2.18.0
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