btrfs: cleanup for extent_write_locked_range()
There are several cleanups for extent_write_locked_range(), most of them
are pure cleanups, but with some preparation for future subpage support.
- Add a proper comment for which call sites are suitable
Unlike regular synchronized extent write back, if async COW or zoned
COW happens, we have all pages in the range still locked.
Thus for those (only) two call sites, we need this function to submit
page content into bios and submit them.
- Remove @mode parameter
All the existing two call sites pass WB_SYNC_ALL. No need for @mode
parameter.
- Better error handling
Currently if we hit an error during the page iteration loop, we
overwrite @ret, causing only the last error can be recorded.
Here we add @found_error and @first_error variable to record if we hit
any error, and the first error we hit.
So the first error won't get lost.
- Don't reuse @start as the cursor
We reuse the parameter @start as the cursor to iterate the range, not
a big problem, but since we're here, introduce a proper @cur as the
cursor.
- Remove impossible branch
Since all pages are still locked after the ordered extent is inserted,
there is no way that pages can get its dirty bit cleared.
Remove the branch where page is not dirty and replace it with an
ASSERT().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index bb47b0b..aaeb219 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -873,8 +873,7 @@ static int submit_one_async_extent(struct btrfs_inode *inode,
* drive.
*/
if (!page_started && !ret)
- extent_write_locked_range(&inode->vfs_inode, start,
- end, WB_SYNC_ALL);
+ extent_write_locked_range(&inode->vfs_inode, start, end);
else if (ret && async_chunk->locked_page)
unlock_page(async_chunk->locked_page);
kfree(async_extent);
@@ -1454,7 +1453,7 @@ static noinline int run_delalloc_zoned(struct btrfs_inode *inode,
__set_page_dirty_nobuffers(locked_page);
account_page_redirty(locked_page);
- extent_write_locked_range(&inode->vfs_inode, start, end, WB_SYNC_ALL);
+ extent_write_locked_range(&inode->vfs_inode, start, end);
*page_started = 1;
return 0;