Btrfs: Deal with failed writes in mirrored configurations

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

4 files changed, 33 insertions, 8 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 1c7d84aff864..e35e70165b53 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1385,7 +1385,10 @@ int write_all_supers(struct btrfs_root *root)
         struct buffer_head *bh;
         int ret;
         int do_barriers;
+        int max_errors;
+        int total_errors = 0;
 
+        max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
         do_barriers = !btrfs_test_opt(root, NOBARRIER);
 
         sb = root->fs_info->sb_buffer;
@@ -1433,8 +1436,14 @@ int write_all_supers(struct btrfs_root *root)
                 } else {
                         ret = submit_bh(WRITE, bh);
                 }
-                BUG_ON(ret);
+                if (ret)
+                        total_errors++;
         }
+        if (total_errors > max_errors) {
+                printk("btrfs: %d errors while writing supers\n", total_errors);
+                BUG();
+        }
+        total_errors = 0;
 
         list_for_each(cur, head) {
                 dev = list_entry(cur, struct btrfs_device, dev_list);
@@ -1454,13 +1463,17 @@ int write_all_supers(struct btrfs_root *root)
                                 wait_on_buffer(bh);
                                 BUG_ON(!buffer_uptodate(bh));
                         } else {
-                                BUG();
+                                total_errors++;
                         }
 
                 }
                 dev->pending_io = NULL;
                 brelse(bh);
         }
+        if (total_errors > max_errors) {
+                printk("btrfs: %d errors while writing supers\n", total_errors);
+                BUG();
+        }
         return 0;
 }
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 95aee5a29375..f94794a99329 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -315,8 +315,8 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
         block_group_cache = &info->block_group_cache;
         total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 
-        if (!owner)
-                factor = 10;
+        if (data & BTRFS_BLOCK_GROUP_METADATA)
+                factor = 9;
 
         bit = block_group_state_bits(data);
 
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)
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 3f9a17f2e41b..a9663e92bb14 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -90,7 +90,8 @@ struct btrfs_multi_bio {
         atomic_t stripes_pending;
         bio_end_io_t *end_io;
         void *private;
-        int error;
+        atomic_t error;
+        int max_errors;
         int num_stripes;
         struct btrfs_bio_stripe stripes[];
 };