Btrfs: Deal with failed writes in mirrored configurations

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

1 files changed, 14 insertions, 3 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9a7241134560..57ab755aca76 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1425,6 +1425,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
         int stripe_index;
         int i;
         int num_stripes;
+        int max_errors = 0;
         struct btrfs_multi_bio *multi = NULL;
 
         if (multi_ret && !(rw & (1 << BIO_RW))) {
@@ -1436,6 +1437,8 @@ again:
                                 GFP_NOFS);
                 if (!multi)
                         return -ENOMEM;
+
+                atomic_set(&multi->error, 0);
         }
 
         spin_lock(&em_tree->lock);
@@ -1462,8 +1465,10 @@ again:
                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
                                  BTRFS_BLOCK_GROUP_DUP)) {
                         stripes_required = map->num_stripes;
+                        max_errors = 1;
                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
                         stripes_required = map->sub_stripes;
+                        max_errors = 1;
                 }
         }
         if (multi_ret && rw == WRITE &&
@@ -1561,6 +1566,7 @@ again:
         if (multi_ret) {
                 *multi_ret = multi;
                 multi->num_stripes = num_stripes;
+                multi->max_errors = max_errors;
         }
 out:
         free_extent_map(em);
@@ -1598,14 +1604,19 @@ static int end_bio_multi_stripe(struct bio *bio,
                 return 1;
 #endif
         if (err)
-                multi->error = err;
+                atomic_inc(&multi->error);
 
         if (atomic_dec_and_test(&multi->stripes_pending)) {
                 bio->bi_private = multi->private;
                 bio->bi_end_io = multi->end_io;
 
-                if (!err && multi->error)
-                        err = multi->error;
+                /* 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)
+                        err = -EIO;
+                else
+                        err = 0;
                 kfree(multi);
 
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)