Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6
[safe/jmp/linux-2.6] / fs / btrfs / volumes.c
index 27d5f37..d6e3af8 100644 (file)
@@ -17,6 +17,7 @@
  */
 #include <linux/sched.h>
 #include <linux/bio.h>
+#include <linux/slab.h>
 #include <linux/buffer_head.h>
 #include <linux/blkdev.h>
 #include <linux/random.h>
@@ -256,13 +257,13 @@ loop_lock:
                        wake_up(&fs_info->async_submit_wait);
 
                BUG_ON(atomic_read(&cur->bi_cnt) == 0);
-               submit_bio(cur->bi_rw, cur);
-               num_run++;
-               batch_run++;
 
-               if (bio_sync(cur))
+               if (bio_rw_flagged(cur, BIO_RW_SYNCIO))
                        num_sync_run++;
 
+               submit_bio(cur->bi_rw, cur);
+               num_run++;
+               batch_run++;
                if (need_resched()) {
                        if (num_sync_run) {
                                blk_run_backing_dev(bdi, NULL);
@@ -276,7 +277,7 @@ loop_lock:
                 * is now congested.  Back off and let other work structs
                 * run instead
                 */
-               if (pending && bdi_write_congested(bdi) && batch_run > 32 &&
+               if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
                    fs_info->fs_devices->open_devices > 1) {
                        struct io_context *ioc;
 
@@ -325,16 +326,6 @@ loop_lock:
                num_sync_run = 0;
                blk_run_backing_dev(bdi, NULL);
        }
-
-       cond_resched();
-       if (again)
-               goto loop;
-
-       spin_lock(&device->io_lock);
-       if (device->pending_bios.head || device->pending_sync_bios.head)
-               goto loop_lock;
-       spin_unlock(&device->io_lock);
-
        /*
         * IO has already been through a long path to get here.  Checksumming,
         * async helper threads, perhaps compression.  We've done a pretty
@@ -346,6 +337,16 @@ loop_lock:
         * cared about found its way down here.
         */
        blk_run_backing_dev(bdi, NULL);
+
+       cond_resched();
+       if (again)
+               goto loop;
+
+       spin_lock(&device->io_lock);
+       if (device->pending_bios.head || device->pending_sync_bios.head)
+               goto loop_lock;
+       spin_unlock(&device->io_lock);
+
 done:
        return 0;
 }
@@ -365,6 +366,7 @@ static noinline int device_list_add(const char *path,
        struct btrfs_device *device;
        struct btrfs_fs_devices *fs_devices;
        u64 found_transid = btrfs_super_generation(disk_super);
+       char *name;
 
        fs_devices = find_fsid(disk_super->fsid);
        if (!fs_devices) {
@@ -377,6 +379,7 @@ static noinline int device_list_add(const char *path,
                memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
                fs_devices->latest_devid = devid;
                fs_devices->latest_trans = found_transid;
+               mutex_init(&fs_devices->device_list_mutex);
                device = NULL;
        } else {
                device = __find_device(&fs_devices->devices, devid,
@@ -403,9 +406,19 @@ static noinline int device_list_add(const char *path,
                        return -ENOMEM;
                }
                INIT_LIST_HEAD(&device->dev_alloc_list);
+
+               mutex_lock(&fs_devices->device_list_mutex);
                list_add(&device->dev_list, &fs_devices->devices);
+               mutex_unlock(&fs_devices->device_list_mutex);
+
                device->fs_devices = fs_devices;
                fs_devices->num_devices++;
+       } else if (strcmp(device->name, path)) {
+               name = kstrdup(path, GFP_NOFS);
+               if (!name)
+                       return -ENOMEM;
+               kfree(device->name);
+               device->name = name;
        }
 
        if (found_transid > fs_devices->latest_trans) {
@@ -429,18 +442,22 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
        INIT_LIST_HEAD(&fs_devices->devices);
        INIT_LIST_HEAD(&fs_devices->alloc_list);
        INIT_LIST_HEAD(&fs_devices->list);
+       mutex_init(&fs_devices->device_list_mutex);
        fs_devices->latest_devid = orig->latest_devid;
        fs_devices->latest_trans = orig->latest_trans;
        memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 
+       mutex_lock(&orig->device_list_mutex);
        list_for_each_entry(orig_dev, &orig->devices, dev_list) {
                device = kzalloc(sizeof(*device), GFP_NOFS);
                if (!device)
                        goto error;
 
                device->name = kstrdup(orig_dev->name, GFP_NOFS);
-               if (!device->name)
+               if (!device->name) {
+                       kfree(device);
                        goto error;
+               }
 
                device->devid = orig_dev->devid;
                device->work.func = pending_bios_fn;
@@ -454,8 +471,10 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
                device->fs_devices = fs_devices;
                fs_devices->num_devices++;
        }
+       mutex_unlock(&orig->device_list_mutex);
        return fs_devices;
 error:
+       mutex_unlock(&orig->device_list_mutex);
        free_fs_devices(fs_devices);
        return ERR_PTR(-ENOMEM);
 }
@@ -466,6 +485,7 @@ int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 
        mutex_lock(&uuid_mutex);
 again:
+       mutex_lock(&fs_devices->device_list_mutex);
        list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
                if (device->in_fs_metadata)
                        continue;
@@ -485,6 +505,7 @@ again:
                kfree(device->name);
                kfree(device);
        }
+       mutex_unlock(&fs_devices->device_list_mutex);
 
        if (fs_devices->seed) {
                fs_devices = fs_devices->seed;
@@ -579,7 +600,7 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                        goto error_close;
 
                disk_super = (struct btrfs_super_block *)bh->b_data;
-               devid = le64_to_cpu(disk_super->dev_item.devid);
+               devid = btrfs_stack_device_id(&disk_super->dev_item);
                if (devid != device->devid)
                        goto error_brelse;
 
@@ -605,6 +626,9 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                device->in_fs_metadata = 0;
                device->mode = flags;
 
+               if (!blk_queue_nonrot(bdev_get_queue(bdev)))
+                       fs_devices->rotating = 1;
+
                fs_devices->open_devices++;
                if (device->writeable) {
                        fs_devices->rw_devices++;
@@ -678,7 +702,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
                goto error_close;
        }
        disk_super = (struct btrfs_super_block *)bh->b_data;
-       devid = le64_to_cpu(disk_super->dev_item.devid);
+       devid = btrfs_stack_device_id(&disk_super->dev_item);
        transid = btrfs_super_generation(disk_super);
        if (disk_super->label[0])
                printk(KERN_INFO "device label %s ", disk_super->label);
@@ -705,9 +729,9 @@ error:
  * called very infrequently and that a given device has a small number
  * of extents
  */
-static noinline int find_free_dev_extent(struct btrfs_trans_handle *trans,
-                                        struct btrfs_device *device,
-                                        u64 num_bytes, u64 *start)
+int find_free_dev_extent(struct btrfs_trans_handle *trans,
+                        struct btrfs_device *device, u64 num_bytes,
+                        u64 *start, u64 *max_avail)
 {
        struct btrfs_key key;
        struct btrfs_root *root = device->dev_root;
@@ -744,9 +768,13 @@ static noinline int find_free_dev_extent(struct btrfs_trans_handle *trans,
        ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
        if (ret < 0)
                goto error;
-       ret = btrfs_previous_item(root, path, 0, key.type);
-       if (ret < 0)
-               goto error;
+       if (ret > 0) {
+               ret = btrfs_previous_item(root, path, key.objectid, key.type);
+               if (ret < 0)
+                       goto error;
+               if (ret > 0)
+                       start_found = 1;
+       }
        l = path->nodes[0];
        btrfs_item_key_to_cpu(l, &key, path->slots[0]);
        while (1) {
@@ -789,6 +817,10 @@ no_more_items:
                        if (last_byte < search_start)
                                last_byte = search_start;
                        hole_size = key.offset - last_byte;
+
+                       if (hole_size > *max_avail)
+                               *max_avail = hole_size;
+
                        if (key.offset > last_byte &&
                            hole_size >= num_bytes) {
                                *start = last_byte;
@@ -1065,7 +1097,7 @@ static int btrfs_rm_dev_item(struct btrfs_root *root,
        if (!path)
                return -ENOMEM;
 
-       trans = btrfs_start_transaction(root, 1);
+       trans = btrfs_start_transaction(root, 0);
        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
        key.type = BTRFS_DEV_ITEM_KEY;
        key.offset = device->devid;
@@ -1111,7 +1143,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                root->fs_info->avail_metadata_alloc_bits;
 
        if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
-           root->fs_info->fs_devices->rw_devices <= 4) {
+           root->fs_info->fs_devices->num_devices <= 4) {
                printk(KERN_ERR "btrfs: unable to go below four devices "
                       "on raid10\n");
                ret = -EINVAL;
@@ -1119,7 +1151,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
        }
 
        if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
-           root->fs_info->fs_devices->rw_devices <= 2) {
+           root->fs_info->fs_devices->num_devices <= 2) {
                printk(KERN_ERR "btrfs: unable to go below two "
                       "devices on raid1\n");
                ret = -EINVAL;
@@ -1132,12 +1164,14 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 
                device = NULL;
                devices = &root->fs_info->fs_devices->devices;
+               mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
                list_for_each_entry(tmp, devices, dev_list) {
                        if (tmp->in_fs_metadata && !tmp->bdev) {
                                device = tmp;
                                break;
                        }
                }
+               mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
                bdev = NULL;
                bh = NULL;
                disk_super = NULL;
@@ -1161,7 +1195,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                        goto error_close;
                }
                disk_super = (struct btrfs_super_block *)bh->b_data;
-               devid = le64_to_cpu(disk_super->dev_item.devid);
+               devid = btrfs_stack_device_id(&disk_super->dev_item);
                dev_uuid = disk_super->dev_item.uuid;
                device = btrfs_find_device(root, devid, dev_uuid,
                                           disk_super->fsid);
@@ -1192,7 +1226,16 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                goto error_brelse;
 
        device->in_fs_metadata = 0;
+
+       /*
+        * the device list mutex makes sure that we don't change
+        * the device list while someone else is writing out all
+        * the device supers.
+        */
+       mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
        list_del_init(&device->dev_list);
+       mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+
        device->fs_devices->num_devices--;
 
        next_device = list_entry(root->fs_info->fs_devices->devices.next,
@@ -1286,6 +1329,7 @@ static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
        seed_devices->opened = 1;
        INIT_LIST_HEAD(&seed_devices->devices);
        INIT_LIST_HEAD(&seed_devices->alloc_list);
+       mutex_init(&seed_devices->device_list_mutex);
        list_splice_init(&fs_devices->devices, &seed_devices->devices);
        list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
        list_for_each_entry(device, &seed_devices->devices, dev_list) {
@@ -1398,8 +1442,8 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
                return -EINVAL;
 
        bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
-       if (!bdev)
-               return -EIO;
+       if (IS_ERR(bdev))
+               return PTR_ERR(bdev);
 
        if (root->fs_info->fs_devices->seeding) {
                seeding_dev = 1;
@@ -1411,6 +1455,10 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
        mutex_lock(&root->fs_info->volume_mutex);
 
        devices = &root->fs_info->fs_devices->devices;
+       /*
+        * we have the volume lock, so we don't need the extra
+        * device list mutex while reading the list here.
+        */
        list_for_each_entry(device, devices, dev_list) {
                if (device->bdev == bdev) {
                        ret = -EEXIST;
@@ -1438,7 +1486,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
                goto error;
        }
 
-       trans = btrfs_start_transaction(root, 1);
+       trans = btrfs_start_transaction(root, 0);
        lock_chunks(root);
 
        device->barriers = 1;
@@ -1465,6 +1513,12 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
        }
 
        device->fs_devices = root->fs_info->fs_devices;
+
+       /*
+        * we don't want write_supers to jump in here with our device
+        * half setup
+        */
+       mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
        list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
        list_add(&device->dev_alloc_list,
                 &root->fs_info->fs_devices->alloc_list);
@@ -1473,6 +1527,9 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
        root->fs_info->fs_devices->rw_devices++;
        root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
 
+       if (!blk_queue_nonrot(bdev_get_queue(bdev)))
+               root->fs_info->fs_devices->rotating = 1;
+
        total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
        btrfs_set_super_total_bytes(&root->fs_info->super_copy,
                                    total_bytes + device->total_bytes);
@@ -1480,6 +1537,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
        total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
        btrfs_set_super_num_devices(&root->fs_info->super_copy,
                                    total_bytes + 1);
+       mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
        if (seeding_dev) {
                ret = init_first_rw_device(trans, root, device);
@@ -1581,6 +1639,7 @@ static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
        device->fs_devices->total_rw_bytes += diff;
 
        device->total_bytes = new_size;
+       device->disk_total_bytes = new_size;
        btrfs_clear_space_info_full(device->dev_root->fs_info);
 
        return btrfs_update_device(trans, device);
@@ -1686,11 +1745,16 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
        extent_root = root->fs_info->extent_root;
        em_tree = &root->fs_info->mapping_tree.map_tree;
 
+       ret = btrfs_can_relocate(extent_root, chunk_offset);
+       if (ret)
+               return -ENOSPC;
+
        /* step one, relocate all the extents inside this chunk */
        ret = btrfs_relocate_block_group(extent_root, chunk_offset);
-       BUG_ON(ret);
+       if (ret)
+               return ret;
 
-       trans = btrfs_start_transaction(root, 1);
+       trans = btrfs_start_transaction(root, 0);
        BUG_ON(!trans);
 
        lock_chunks(root);
@@ -1699,9 +1763,9 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
         * step two, delete the device extents and the
         * chunk tree entries
         */
-       spin_lock(&em_tree->lock);
+       read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, chunk_offset, 1);
-       spin_unlock(&em_tree->lock);
+       read_unlock(&em_tree->lock);
 
        BUG_ON(em->start > chunk_offset ||
               em->start + em->len < chunk_offset);
@@ -1730,9 +1794,9 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
        ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
        BUG_ON(ret);
 
-       spin_lock(&em_tree->lock);
+       write_lock(&em_tree->lock);
        remove_extent_mapping(em_tree, em);
-       spin_unlock(&em_tree->lock);
+       write_unlock(&em_tree->lock);
 
        kfree(map);
        em->bdev = NULL;
@@ -1757,12 +1821,15 @@ static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
        struct btrfs_key found_key;
        u64 chunk_tree = chunk_root->root_key.objectid;
        u64 chunk_type;
+       bool retried = false;
+       int failed = 0;
        int ret;
 
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
 
+again:
        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
        key.offset = (u64)-1;
        key.type = BTRFS_CHUNK_ITEM_KEY;
@@ -1792,7 +1859,10 @@ static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
                        ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
                                                   found_key.objectid,
                                                   found_key.offset);
-                       BUG_ON(ret);
+                       if (ret == -ENOSPC)
+                               failed++;
+                       else if (ret)
+                               BUG();
                }
 
                if (found_key.offset == 0)
@@ -1800,6 +1870,14 @@ static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
                key.offset = found_key.offset - 1;
        }
        ret = 0;
+       if (failed && !retried) {
+               failed = 0;
+               retried = true;
+               goto again;
+       } else if (failed && retried) {
+               WARN_ON(1);
+               ret = -ENOSPC;
+       }
 error:
        btrfs_free_path(path);
        return ret;
@@ -1844,9 +1922,11 @@ int btrfs_balance(struct btrfs_root *dev_root)
                        continue;
 
                ret = btrfs_shrink_device(device, old_size - size_to_free);
+               if (ret == -ENOSPC)
+                       break;
                BUG_ON(ret);
 
-               trans = btrfs_start_transaction(dev_root, 1);
+               trans = btrfs_start_transaction(dev_root, 0);
                BUG_ON(!trans);
 
                ret = btrfs_grow_device(trans, device, old_size);
@@ -1888,9 +1968,8 @@ int btrfs_balance(struct btrfs_root *dev_root)
                chunk = btrfs_item_ptr(path->nodes[0],
                                       path->slots[0],
                                       struct btrfs_chunk);
-               key.offset = found_key.offset;
                /* chunk zero is special */
-               if (key.offset == 0)
+               if (found_key.offset == 0)
                        break;
 
                btrfs_release_path(chunk_root, path);
@@ -1898,7 +1977,8 @@ int btrfs_balance(struct btrfs_root *dev_root)
                                           chunk_root->root_key.objectid,
                                           found_key.objectid,
                                           found_key.offset);
-               BUG_ON(ret);
+               BUG_ON(ret && ret != -ENOSPC);
+               key.offset = found_key.offset - 1;
        }
        ret = 0;
 error:
@@ -1924,10 +2004,13 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
        u64 chunk_offset;
        int ret;
        int slot;
+       int failed = 0;
+       bool retried = false;
        struct extent_buffer *l;
        struct btrfs_key key;
        struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
        u64 old_total = btrfs_super_total_bytes(super_copy);
+       u64 old_size = device->total_bytes;
        u64 diff = device->total_bytes - new_size;
 
        if (new_size >= device->total_bytes)
@@ -1937,12 +2020,6 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
        if (!path)
                return -ENOMEM;
 
-       trans = btrfs_start_transaction(root, 1);
-       if (!trans) {
-               ret = -ENOMEM;
-               goto done;
-       }
-
        path->reada = 2;
 
        lock_chunks(root);
@@ -1951,8 +2028,8 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
        if (device->writeable)
                device->fs_devices->total_rw_bytes -= diff;
        unlock_chunks(root);
-       btrfs_end_transaction(trans, root);
 
+again:
        key.objectid = device->devid;
        key.offset = (u64)-1;
        key.type = BTRFS_DEV_EXTENT_KEY;
@@ -1967,21 +2044,26 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
                        goto done;
                if (ret) {
                        ret = 0;
-                       goto done;
+                       btrfs_release_path(root, path);
+                       break;
                }
 
                l = path->nodes[0];
                slot = path->slots[0];
                btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 
-               if (key.objectid != device->devid)
-                       goto done;
+               if (key.objectid != device->devid) {
+                       btrfs_release_path(root, path);
+                       break;
+               }
 
                dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
                length = btrfs_dev_extent_length(l, dev_extent);
 
-               if (key.offset + length <= new_size)
+               if (key.offset + length <= new_size) {
+                       btrfs_release_path(root, path);
                        break;
+               }
 
                chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
                chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
@@ -1990,16 +2072,30 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 
                ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
                                           chunk_offset);
-               if (ret)
+               if (ret && ret != -ENOSPC)
                        goto done;
+               if (ret == -ENOSPC)
+                       failed++;
+               key.offset -= 1;
        }
 
-       /* Shrinking succeeded, else we would be at "done". */
-       trans = btrfs_start_transaction(root, 1);
-       if (!trans) {
-               ret = -ENOMEM;
+       if (failed && !retried) {
+               failed = 0;
+               retried = true;
+               goto again;
+       } else if (failed && retried) {
+               ret = -ENOSPC;
+               lock_chunks(root);
+
+               device->total_bytes = old_size;
+               if (device->writeable)
+                       device->fs_devices->total_rw_bytes += diff;
+               unlock_chunks(root);
                goto done;
        }
+
+       /* Shrinking succeeded, else we would be at "done". */
+       trans = btrfs_start_transaction(root, 0);
        lock_chunks(root);
 
        device->disk_total_bytes = new_size;
@@ -2100,9 +2196,9 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                min_stripes = 2;
        }
        if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
-               num_stripes = min_t(u64, 2, fs_devices->rw_devices);
-               if (num_stripes < 2)
+               if (fs_devices->rw_devices < 2)
                        return -ENOSPC;
+               num_stripes = 2;
                min_stripes = 2;
        }
        if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
@@ -2118,7 +2214,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                max_chunk_size = 10 * calc_size;
                min_stripe_size = 64 * 1024 * 1024;
        } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
-               max_chunk_size = 4 * calc_size;
+               max_chunk_size = 256 * 1024 * 1024;
                min_stripe_size = 32 * 1024 * 1024;
        } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
                calc_size = 8 * 1024 * 1024;
@@ -2131,6 +2227,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                             max_chunk_size);
 
 again:
+       max_avail = 0;
        if (!map || map->num_stripes != num_stripes) {
                kfree(map);
                map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
@@ -2145,8 +2242,16 @@ again:
                do_div(calc_size, stripe_len);
                calc_size *= stripe_len;
        }
+
        /* we don't want tiny stripes */
-       calc_size = max_t(u64, min_stripe_size, calc_size);
+       if (!looped)
+               calc_size = max_t(u64, min_stripe_size, calc_size);
+
+       /*
+        * we're about to do_div by the stripe_len so lets make sure
+        * we end up with something bigger than a stripe
+        */
+       calc_size = max_t(u64, calc_size, stripe_len * 4);
 
        do_div(calc_size, stripe_len);
        calc_size *= stripe_len;
@@ -2179,7 +2284,8 @@ again:
 
                if (device->in_fs_metadata && avail >= min_free) {
                        ret = find_free_dev_extent(trans, device,
-                                                  min_free, &dev_offset);
+                                                  min_free, &dev_offset,
+                                                  &max_avail);
                        if (ret == 0) {
                                list_move_tail(&device->dev_alloc_list,
                                               &private_devs);
@@ -2242,9 +2348,9 @@ again:
        em->block_len = em->len;
 
        em_tree = &extent_root->fs_info->mapping_tree.map_tree;
-       spin_lock(&em_tree->lock);
+       write_lock(&em_tree->lock);
        ret = add_extent_mapping(em_tree, em);
-       spin_unlock(&em_tree->lock);
+       write_unlock(&em_tree->lock);
        BUG_ON(ret);
        free_extent_map(em);
 
@@ -2439,12 +2545,17 @@ int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
        int readonly = 0;
        int i;
 
-       spin_lock(&map_tree->map_tree.lock);
+       read_lock(&map_tree->map_tree.lock);
        em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
-       spin_unlock(&map_tree->map_tree.lock);
+       read_unlock(&map_tree->map_tree.lock);
        if (!em)
                return 1;
 
+       if (btrfs_test_opt(root, DEGRADED)) {
+               free_extent_map(em);
+               return 0;
+       }
+
        map = (struct map_lookup *)em->bdev;
        for (i = 0; i < map->num_stripes; i++) {
                if (!map->stripes[i].dev->writeable) {
@@ -2466,11 +2577,11 @@ void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
        struct extent_map *em;
 
        while (1) {
-               spin_lock(&tree->map_tree.lock);
+               write_lock(&tree->map_tree.lock);
                em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
                if (em)
                        remove_extent_mapping(&tree->map_tree, em);
-               spin_unlock(&tree->map_tree.lock);
+               write_unlock(&tree->map_tree.lock);
                if (!em)
                        break;
                kfree(em->bdev);
@@ -2488,9 +2599,9 @@ int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
        struct extent_map_tree *em_tree = &map_tree->map_tree;
        int ret;
 
-       spin_lock(&em_tree->lock);
+       read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, logical, len);
-       spin_unlock(&em_tree->lock);
+       read_unlock(&em_tree->lock);
        BUG_ON(!em);
 
        BUG_ON(em->start > logical || em->start + em->len < logical);
@@ -2552,12 +2663,14 @@ again:
                atomic_set(&multi->error, 0);
        }
 
-       spin_lock(&em_tree->lock);
+       read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, logical, *length);
-       spin_unlock(&em_tree->lock);
+       read_unlock(&em_tree->lock);
 
-       if (!em && unplug_page)
+       if (!em && unplug_page) {
+               kfree(multi);
                return 0;
+       }
 
        if (!em) {
                printk(KERN_CRIT "unable to find logical %llu len %llu\n",
@@ -2711,9 +2824,9 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
        u64 stripe_nr;
        int i, j, nr = 0;
 
-       spin_lock(&em_tree->lock);
+       read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, chunk_start, 1);
-       spin_unlock(&em_tree->lock);
+       read_unlock(&em_tree->lock);
 
        BUG_ON(!em || em->start != chunk_start);
        map = (struct map_lookup *)em->bdev;
@@ -2755,26 +2868,6 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
                }
        }
 
-       for (i = 0; i > nr; i++) {
-               struct btrfs_multi_bio *multi;
-               struct btrfs_bio_stripe *stripe;
-               int ret;
-
-               length = 1;
-               ret = btrfs_map_block(map_tree, WRITE, buf[i],
-                                     &length, &multi, 0);
-               BUG_ON(ret);
-
-               stripe = multi->stripes;
-               for (j = 0; j < multi->num_stripes; j++) {
-                       if (stripe->physical >= physical &&
-                           physical < stripe->physical + length)
-                               break;
-               }
-               BUG_ON(j >= multi->num_stripes);
-               kfree(multi);
-       }
-
        *logical = buf;
        *naddrs = nr;
        *stripe_len = map->stripe_len;
@@ -2871,7 +2964,7 @@ static noinline int schedule_bio(struct btrfs_root *root,
        bio->bi_rw |= rw;
 
        spin_lock(&device->io_lock);
-       if (bio_sync(bio))
+       if (bio_rw_flagged(bio, BIO_RW_SYNCIO))
                pending_bios = &device->pending_sync_bios;
        else
                pending_bios = &device->pending_bios;
@@ -3021,9 +3114,9 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
        logical = key->offset;
        length = btrfs_chunk_length(leaf, chunk);
 
-       spin_lock(&map_tree->map_tree.lock);
+       read_lock(&map_tree->map_tree.lock);
        em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
-       spin_unlock(&map_tree->map_tree.lock);
+       read_unlock(&map_tree->map_tree.lock);
 
        /* already mapped? */
        if (em && em->start <= logical && em->start + em->len > logical) {
@@ -3082,9 +3175,9 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                map->stripes[i].dev->in_fs_metadata = 1;
        }
 
-       spin_lock(&map_tree->map_tree.lock);
+       write_lock(&map_tree->map_tree.lock);
        ret = add_extent_mapping(&map_tree->map_tree, em);
-       spin_unlock(&map_tree->map_tree.lock);
+       write_unlock(&map_tree->map_tree.lock);
        BUG_ON(ret);
        free_extent_map(em);
 
@@ -3302,6 +3395,8 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
        key.type = 0;
 again:
        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+       if (ret < 0)
+               goto error;
        while (1) {
                leaf = path->nodes[0];
                slot = path->slots[0];