[PATCH v3 13/22] btrfs: subpage: introduce helper for subpage error status

[Qu Wenruo <wqu@suse.com>]

This patch introduce the following functions to handle btrfs subpage
error status:
- btrfs_subpage_set_error()
- btrfs_subpage_clear_error()
- btrfs_subpage_test_error()
  Those helpers can only be called when the range is ensured to be
  inside the page.

- btrfs_page_set_error()
- btrfs_page_clear_error()
- btrfs_page_test_error()
  Those helpers can handle both regular sector size and subpage without
  problem.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/subpage.h | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 2b2d25cc6cba..25f6d0cd1a1e 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -24,6 +24,7 @@ struct btrfs_subpage {
 	/* Common members for both data and metadata pages */
 	spinlock_t lock;
 	u16 uptodate_bitmap;
+	u16 error_bitmap;
 	union {
 		/* Structures only used by metadata */
 		struct {
@@ -130,6 +131,35 @@ static inline void btrfs_subpage_clear_uptodate(struct btrfs_fs_info *fs_info,
 	spin_unlock_irqrestore(&subpage->lock, flags);
 }
 
+static inline void btrfs_subpage_set_error(struct btrfs_fs_info *fs_info,
+					   struct page *page, u64 start,
+					   u32 len)
+{
+	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
+	u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len);
+	unsigned long flags;
+
+	spin_lock_irqsave(&subpage->lock, flags);
+	subpage->error_bitmap |= tmp;
+	SetPageError(page);
+	spin_unlock_irqrestore(&subpage->lock, flags);
+}
+
+static inline void btrfs_subpage_clear_error(struct btrfs_fs_info *fs_info,
+					   struct page *page, u64 start,
+					   u32 len)
+{
+	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
+	u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len);
+	unsigned long flags;
+
+	spin_lock_irqsave(&subpage->lock, flags);
+	subpage->error_bitmap &= ~tmp;
+	if (subpage->error_bitmap == 0)
+		ClearPageError(page);
+	spin_unlock_irqrestore(&subpage->lock, flags);
+}
+
 /*
  * Unlike set/clear which is dependent on each page status, for test all bits
  * are tested in the same way.
@@ -149,6 +179,7 @@ static inline bool btrfs_subpage_test_##name(struct btrfs_fs_info *fs_info, \
 	return ret;							\
 }
 DECLARE_BTRFS_SUBPAGE_TEST_OP(uptodate);
+DECLARE_BTRFS_SUBPAGE_TEST_OP(error);
 
 /*
  * Note that, in selftest, especially extent-io-tests, we can have empty
@@ -185,5 +216,6 @@ static inline bool btrfs_page_test_##name(struct btrfs_fs_info *fs_info, \
 }
 DECLARE_BTRFS_PAGE_OPS(uptodate, SetPageUptodate, ClearPageUptodate,
 			PageUptodate);
+DECLARE_BTRFS_PAGE_OPS(error, SetPageError, ClearPageError, PageError);
 
 #endif /* BTRFS_SUBPAGE_H */
-- 
2.29.2