@@ -4994,25 +4994,12 @@ int extent_buffer_under_io(const struct extent_buffer *eb)
test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
}
-/*
- * Release all pages attached to the extent buffer.
- */
-static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
+static void detach_extent_buffer_page(struct extent_buffer *eb,
+ struct page *page)
{
- int i;
- int num_pages;
- int mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
-
- BUG_ON(extent_buffer_under_io(eb));
-
- num_pages = num_extent_pages(eb);
- for (i = 0; i < num_pages; i++) {
- struct page *page = eb->pages[i];
+ struct btrfs_fs_info *fs_info = eb->fs_info;
- if (!page)
- continue;
- if (mapped)
- spin_lock(&page->mapping->private_lock);
+ if (fs_info->sectorsize == PAGE_SIZE) {
/*
* We do this since we'll remove the pages after we've
* removed the eb from the radix tree, so we could race
@@ -5031,6 +5018,44 @@ static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
*/
detach_page_private(page);
}
+ return;
+ }
+
+ /*
+ * For subpage case, clear the range in tree_block_bitmap,
+ * and if we're the last one, detach private completely.
+ */
+ if (PagePrivate(page)) {
+ bool last = false;
+
+ last = btrfs_subpage_clear_and_test_tree_block(fs_info, page,
+ eb->start, eb->len);
+ if (last)
+ btrfs_detach_subpage(fs_info, page);
+ }
+}
+
+/*
+ * Release all pages attached to the extent buffer.
+ */
+static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
+{
+ int i;
+ int num_pages;
+ int mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
+
+ ASSERT(!extent_buffer_under_io(eb));
+
+ num_pages = num_extent_pages(eb);
+ for (i = 0; i < num_pages; i++) {
+ struct page *page = eb->pages[i];
+
+ if (!page)
+ continue;
+ if (mapped)
+ spin_lock(&page->mapping->private_lock);
+
+ detach_extent_buffer_page(eb, page);
if (mapped)
spin_unlock(&page->mapping->private_lock);
@@ -72,4 +72,28 @@ static inline void btrfs_subpage_set_tree_block(struct btrfs_fs_info *fs_info,
spin_unlock_irqrestore(&subpage->lock, flags);
}
+/*
+ * Clear the bits in tree_block_bitmap and return if we're the last bit set
+ * int tree_block_bitmap.
+ *
+ * Return true if we're the last bits in the tree_block_bitmap.
+ * Return false otherwise.
+ */
+static inline bool btrfs_subpage_clear_and_test_tree_block(
+ 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;
+ bool last = false;
+
+ spin_lock_irqsave(&subpage->lock, flags);
+ subpage->tree_block_bitmap &= ~tmp;
+ if (subpage->tree_block_bitmap == 0)
+ last = true;
+ spin_unlock_irqrestore(&subpage->lock, flags);
+ return last;
+}
+
#endif /* BTRFS_SUBPAGE_H */
In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. To do so, introduce a new helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, the new trick is to clear the range of current extent buffer, and detach page private if and only if we're the last tree block of the page. This part is handled by the subpage helper, btrfs_subpage_clear_and_test_tree_block(). Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/extent_io.c | 59 +++++++++++++++++++++++++++++++------------- fs/btrfs/subpage.h | 24 ++++++++++++++++++ 2 files changed, 66 insertions(+), 17 deletions(-)