Btrfs: Handle write errors on raid1 and raid10

When duplicate copies exist, writes are allowed to fail to one of those
copies.  This changeset includes a few changes that allow the FS to
continue even when some IOs fail.

It also adds verification of the parent generation number for btree blocks.
This generation is stored in the pointer to a block, and it ensures
that missed writes to are detected.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 41 insertions, 8 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index dd403b426ff..2a3624adc0c 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1366,7 +1366,7 @@ static int end_bio_extent_writepage(struct bio *bio,
 				   unsigned int bytes_done, int err)
 #endif
 {
-	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+	int uptodate = err == 0;
 	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
 	struct extent_state *state = bio->bi_private;
 	struct extent_io_tree *tree = state->tree;
@@ -1375,6 +1375,7 @@ static int end_bio_extent_writepage(struct bio *bio,
 	u64 end;
 	u64 cur;
 	int whole_page;
+	int ret;
 	unsigned long flags;
 
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
@@ -1395,17 +1396,30 @@ static int end_bio_extent_writepage(struct bio *bio,
 		if (--bvec >= bio->bi_io_vec)
 			prefetchw(&bvec->bv_page->flags);
 
+		if (tree->ops && tree->ops->writepage_end_io_hook) {
+			ret = tree->ops->writepage_end_io_hook(page, start,
+						       end, state);
+			if (ret)
+				uptodate = 0;
+		}
+
+		if (!uptodate && tree->ops &&
+		    tree->ops->writepage_io_failed_hook) {
+			ret = tree->ops->writepage_io_failed_hook(bio, page,
+							 start, end, state);
+			if (ret == 0) {
+				state = NULL;
+				uptodate = (err == 0);
+				continue;
+			}
+		}
+
 		if (!uptodate) {
 			clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
 			ClearPageUptodate(page);
 			SetPageError(page);
 		}
 
-		if (tree->ops && tree->ops->writepage_end_io_hook) {
-			tree->ops->writepage_end_io_hook(page, start, end,
-							 state);
-		}
-
 		/*
 		 * bios can get merged in funny ways, and so we need to
 		 * be careful with the state variable.  We know the
@@ -2073,9 +2087,9 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 		} else {
 			ret = 0;
 		}
-		if (ret)
+		if (ret) {
 			SetPageError(page);
-		else {
+		} else {
 			unsigned long max_nr = end_index + 1;
 			set_range_writeback(tree, cur, cur + iosize - 1);
 			if (!PageWriteback(page)) {
@@ -2948,6 +2962,25 @@ int set_extent_buffer_dirty(struct extent_io_tree *tree,
 }
 EXPORT_SYMBOL(set_extent_buffer_dirty);
 
+int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
+				struct extent_buffer *eb)
+{
+	unsigned long i;
+	struct page *page;
+	unsigned long num_pages;
+
+	num_pages = num_extent_pages(eb->start, eb->len);
+	eb->flags &= ~EXTENT_UPTODATE;
+
+	clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
+			      GFP_NOFS);
+	for (i = 0; i < num_pages; i++) {
+		page = extent_buffer_page(eb, i);
+		ClearPageUptodate(page);
+	}
+	return 0;
+}
+
 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
 				struct extent_buffer *eb)
 {