[PATCH v5 09/18] btrfs: introduce helpers for subpage error status

[Qu Wenruo]

Introduce the following functions to handle subpage error status:

- btrfs_subpage_set_error()
- btrfs_subpage_clear_error()
- btrfs_subpage_test_error()
  These helpers can only be called when the page has subpage attached
  and the range is ensured to be inside the page.

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

Signed-off-by: Qu Wenruo <w...@suse.com>
Reviewed-by: David Sterba <dste...@suse.com>
Signed-off-by: David Sterba <dste...@suse.com>
---
 fs/btrfs/subpage.c | 29 +++++++++++++++++++++++++++++
 fs/btrfs/subpage.h |  2 ++
 2 files changed, 31 insertions(+)

diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index 50b56e58ca93..2fe55a712557 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -161,6 +161,33 @@ void btrfs_subpage_clear_uptodate(const struct 
btrfs_fs_info *fs_info,
        spin_unlock_irqrestore(&subpage->lock, flags);
 }
 
+void btrfs_subpage_set_error(const struct btrfs_fs_info *fs_info,
+               struct page *page, u64 start, u32 len)
+{
+       struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
+       const 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);
+}
+
+void btrfs_subpage_clear_error(const struct btrfs_fs_info *fs_info,
+               struct page *page, u64 start, u32 len)
+{
+       struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
+       const 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.
@@ -180,6 +207,7 @@ bool btrfs_subpage_test_##name(const struct btrfs_fs_info 
*fs_info, \
        return ret;                                                     \
 }
 IMPLEMENT_BTRFS_SUBPAGE_TEST_OP(uptodate);
+IMPLEMENT_BTRFS_SUBPAGE_TEST_OP(error);
 
 /*
  * Note that, in selftests (extent-io-tests), we can have empty fs_info passed
@@ -215,3 +243,4 @@ bool btrfs_page_test_##name(const struct btrfs_fs_info 
*fs_info,    \
 }
 IMPLEMENT_BTRFS_PAGE_OPS(uptodate, SetPageUptodate, ClearPageUptodate,
                         PageUptodate);
+IMPLEMENT_BTRFS_PAGE_OPS(error, SetPageError, ClearPageError, PageError);
diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 1dee4eb1c5c1..68cbfc4f6765 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -20,6 +20,7 @@ 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
@@ -78,5 +79,6 @@ bool btrfs_page_test_##name(const struct btrfs_fs_info 
*fs_info,      \
                struct page *page, u64 start, u32 len);
 
 DECLARE_BTRFS_SUBPAGE_OPS(uptodate);
+DECLARE_BTRFS_SUBPAGE_OPS(error);
 
 #endif
-- 
2.30.0