Btrfs: Deal with failed writes in mirrored configurations

[linux-2.6-block.git] / fs / btrfs / volumes.c

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9a72411345608dbdd03292151e93f51df36384c5..57ab755aca76b3f70cd8c6a44a2c18364a52a38d 100644 (file)
--- 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)