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, 8 insertions, 3 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b5d7bd1915b4..5fc7fb481474 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1807,14 +1807,19 @@ static int end_bio_multi_stripe(struct bio *bio,
         if (atomic_dec_and_test(&multi->stripes_pending)) {
                 bio->bi_private = multi->private;
                 bio->bi_end_io = multi->end_io;
-
                 /* only send an error to the higher layers if it is
                  * beyond the tolerance of the multi-bio
                  */
-                if (atomic_read(&multi->error) > multi->max_errors)
+                if (atomic_read(&multi->error) > multi->max_errors) {
                         err = -EIO;
-                else
+                } else if (err) {
+                        /*
+                         * this bio is actually up to date, we didn't
+                         * go over the max number of errors
+                         */
+                        set_bit(BIO_UPTODATE, &bio->bi_flags);
                         err = 0;
+                }
                 kfree(multi);
 
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)