Fix corners in writepage and btrfs_truncate_page

The extent_io writepage calls needed an extra check for discarding pages that started on th last byte in the file. btrfs_truncate_page needed checks to make sure the page was still part of the file after reading it, and most importantly, needed to wait for all IO to the page to finish before freeing the corresponding extents on disk. Signed-off-by: Chris Mason <[email protected]>
qwerty123443 · Sep 25, 2008 · 211c17f · 211c17f
1 parent a0af469
commit 211c17f
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Showing 3 changed files with 17 additions and 15 deletions.
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
@@ -1988,23 +1988,26 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	u64 nr_delalloc;
 	u64 delalloc_end;
 
+
 	WARN_ON(!PageLocked(page));
-	if (page->index > end_index) {
-		clear_extent_dirty(tree, start, page_end, GFP_NOFS);
+	page_offset = i_size & (PAGE_CACHE_SIZE - 1);
+	if (page->index > end_index ||
+	   (page->index == end_index && !page_offset)) {
+		page->mapping->a_ops->invalidatepage(page, 0);
 		unlock_page(page);
 		return 0;
 	}
 
 	if (page->index == end_index) {
 		char *userpage;
 
-		size_t offset = i_size & (PAGE_CACHE_SIZE - 1);
-
 		userpage = kmap_atomic(page, KM_USER0);
-		memset(userpage + offset, 0, PAGE_CACHE_SIZE - offset);
-		flush_dcache_page(page);
+		memset(userpage + page_offset, 0,
+		       PAGE_CACHE_SIZE - page_offset);
 		kunmap_atomic(userpage, KM_USER0);
+		flush_dcache_page(page);
 	}
+	page_offset = 0;
 
 	set_page_extent_mapped(page);
 

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
@@ -305,7 +305,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 	    (inline_size & (root->sectorsize -1)) == 0 ||
 	    inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
 		u64 last_end;
-		u64 existing_delalloc = 0;
 
 		for (i = 0; i < num_pages; i++) {
 			struct page *p = pages[i];
@@ -315,13 +314,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 		last_end = (u64)(pages[num_pages -1]->index) <<
 				PAGE_CACHE_SHIFT;
 		last_end += PAGE_CACHE_SIZE - 1;
-		if (start_pos < isize) {
-			u64 delalloc_start = start_pos;
-			existing_delalloc = count_range_bits(io_tree,
-					     &delalloc_start,
-					     end_of_last_block, (u64)-1,
-					     EXTENT_DELALLOC);
-		}
 		set_extent_delalloc(io_tree, start_pos, end_of_last_block,
 				 GFP_NOFS);
 		btrfs_add_ordered_inode(inode);

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
@@ -1180,19 +1180,26 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
 		goto out;
 
 	ret = -ENOMEM;
+again:
 	page = grab_cache_page(mapping, index);
 	if (!page)
 		goto out;
 	if (!PageUptodate(page)) {
 		ret = btrfs_readpage(NULL, page);
 		lock_page(page);
+		if (page->mapping != mapping) {
+			unlock_page(page);
+			page_cache_release(page);
+			goto again;
+		}
 		if (!PageUptodate(page)) {
 			ret = -EIO;
 			goto out;
 		}
 	}
-	page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 
+	page_start = (u64)page->index << PAGE_CACHE_SHIFT;
+	wait_on_page_writeback(page);
 	ret = btrfs_cow_one_page(inode, page, offset);
 
 	unlock_page(page);