--- fs/btrfs/volumes.c

+++ fs/btrfs/volumes.c

@@ -1135,7 +1135,7 @@ int btrfs_rm_device(struct btrfs_root *r

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;

@@ -1143,7 +1143,7 @@ int btrfs_rm_device(struct btrfs_root *r

}

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;

@@ -1434,8 +1434,8 @@ int btrfs_init_new_device(struct btrfs_r

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;

@@ -2209,7 +2209,7 @@ static int __btrfs_alloc_chunk(struct bt

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;

@@ -2538,6 +2538,11 @@ int btrfs_chunk_readonly(struct btrfs_ro

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) {

@@ -2649,8 +2654,10 @@ again:

em = lookup_extent_mapping(em_tree, logical, *length);

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",