On 12/10/20 1:38 AM, Qu Wenruo wrote:
The refactor involves the following modifications:
- iosize alignment
In fact we don't really need to manually do alignment at all.
All extent maps should already be aligned, thus basic ASSERT() check
would be enough.
- redundant variables
We have extra variable like blocksize/pg_offset/end.
They are all unnecessary.
@blocksize can be replaced by sectorsize size directly, and it's only
used to verify the em start/size is aligned.
@pg_offset can be easily calculated using @cur and page_offset(page).
@end is just assigned to @page_end and never modified, use @page_end
to replace it.
- remove some BUG_ON()s
The BUG_ON()s are for extent map, which we have tree-checker to check
on-disk extent data item and runtime check.
ASSERT() should be enough.
Signed-off-by: Qu Wenruo <[email protected]>
---
fs/btrfs/extent_io.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2650e8720394..612fe60b367e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3515,17 +3515,14 @@ static noinline_for_stack int
__extent_writepage_io(struct btrfs_inode *inode,
unsigned long nr_written,
int *nr_ret)
{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct extent_io_tree *tree = &inode->io_tree;
u64 start = page_offset(page);
u64 page_end = start + PAGE_SIZE - 1;
- u64 end;
u64 cur = start;
u64 extent_offset;
u64 block_start;
- u64 iosize;
struct extent_map *em;
- size_t pg_offset = 0;
- size_t blocksize;
int ret = 0;
int nr = 0;
const unsigned int write_flags = wbc_to_write_flags(wbc);
@@ -3546,19 +3543,17 @@ static noinline_for_stack int
__extent_writepage_io(struct btrfs_inode *inode,
*/
update_nr_written(wbc, nr_written + 1);
- end = page_end;
- blocksize = inode->vfs_inode.i_sb->s_blocksize;
-
- while (cur <= end) {
+ while (cur <= page_end) {
u64 disk_bytenr;
u64 em_end;
+ u32 iosize;
if (cur >= i_size) {
btrfs_writepage_endio_finish_ordered(page, cur,
page_end, 1);
break;
}
- em = btrfs_get_extent(inode, NULL, 0, cur, end - cur + 1);
+ em = btrfs_get_extent(inode, NULL, 0, cur, page_end - cur + 1);
if (IS_ERR_OR_NULL(em)) {
SetPageError(page);
ret = PTR_ERR_OR_ZERO(em);
@@ -3567,16 +3562,20 @@ static noinline_for_stack int
__extent_writepage_io(struct btrfs_inode *inode,
extent_offset = cur - em->start;
em_end = extent_map_end(em);
- BUG_ON(em_end <= cur);
- BUG_ON(end < cur);
- iosize = min(em_end - cur, end - cur + 1);
- iosize = ALIGN(iosize, blocksize);
- disk_bytenr = em->block_start + extent_offset;
+ ASSERT(cur <= em_end);
+ ASSERT(cur < page_end);
+ ASSERT(IS_ALIGNED(em->start, fs_info->sectorsize));
+ ASSERT(IS_ALIGNED(em->len, fs_info->sectorsize));
block_start = em->block_start;
compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+ disk_bytenr = em->block_start + extent_offset;
+
+ /* Note that em_end from extent_map_end() is exclusive */
+ iosize = min(em_end, page_end + 1) - cur;
free_extent_map(em);
em = NULL;
+
Random extra whitespace. Once you fix you can add
Reviewed-by: Josef Bacik <[email protected]>
Thanks,
Josef
