Btrfs: Search for all ordered extents that could span across a page

In subpagesize-blocksize scenario it is not sufficient to search using the
first byte of the page to make sure that there are no ordered extents
present across the page. Fix this.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -3186,7 +3186,8 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
 
 	while (1) {
 		lock_extent(tree, start, end);
-		ordered = btrfs_lookup_ordered_extent(inode, start);
+		ordered = btrfs_lookup_ordered_range(inode, start,
+						PAGE_CACHE_SIZE);
 		if (!ordered)
 			break;
 		unlock_extent(tree, start, end);

fs/btrfs/inode.c

@@ -2002,7 +2002,8 @@ again:
 	if (PagePrivate2(page))
 		goto out;
 
-	ordered = btrfs_lookup_ordered_extent(inode, page_start);
+	ordered = btrfs_lookup_ordered_range(inode, page_start,
+					PAGE_CACHE_SIZE);
 	if (ordered) {
 		unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
 				     page_end, &cached_state, GFP_NOFS);
@@ -8683,6 +8684,8 @@ static void btrfs_invalidatepage(struct page *page, unsigned int offset,
 	struct extent_state *cached_state = NULL;
 	u64 page_start = page_offset(page);
 	u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
+	u64 start;
+	u64 end;
 	int inode_evicting = inode->i_state & I_FREEING;
 
 	/*
@@ -8702,14 +8705,18 @@ static void btrfs_invalidatepage(struct page *page, unsigned int offset,
 
 	if (!inode_evicting)
 		lock_extent_bits(tree, page_start, page_end, &cached_state);
-	ordered = btrfs_lookup_ordered_extent(inode, page_start);
+again:
+	start = page_start;
+	ordered = btrfs_lookup_ordered_range(inode, start,
+					page_end - start + 1);
 	if (ordered) {
+		end = min(page_end, ordered->file_offset + ordered->len - 1);
 		/*
 		 * IO on this page will never be started, so we need
 		 * to account for any ordered extents now
 		 */
 		if (!inode_evicting)
-			clear_extent_bit(tree, page_start, page_end,
+			clear_extent_bit(tree, start, end,
 					 EXTENT_DIRTY | EXTENT_DELALLOC |
 					 EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
 					 EXTENT_DEFRAG, 1, 0, &cached_state,
@@ -8726,22 +8733,26 @@ static void btrfs_invalidatepage(struct page *page, unsigned int offset,
 
 			spin_lock_irq(&tree->lock);
 			set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
-			new_len = page_start - ordered->file_offset;
+			new_len = start - ordered->file_offset;
 			if (new_len < ordered->truncated_len)
 				ordered->truncated_len = new_len;
 			spin_unlock_irq(&tree->lock);
 
 			if (btrfs_dec_test_ordered_pending(inode, &ordered,
-							   page_start,
+							   start,
-							   PAGE_CACHE_SIZE, 1))
+							   end - start + 1, 1))
 				btrfs_finish_ordered_io(ordered);
 		}
 		btrfs_put_ordered_extent(ordered);
 		if (!inode_evicting) {
 			cached_state = NULL;
-			lock_extent_bits(tree, page_start, page_end,
+			lock_extent_bits(tree, start, end,
 					 &cached_state);
 		}
+
+		start = end + 1;
+		if (start < page_end)
+			goto again;
 	}
 
 	/*