Btrfs: Add balance ioctl to restripe the chunks

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

5 files changed, 208 insertions, 27 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b9257b37bb96..73b92dd150ff 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1364,7 +1364,7 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
                        u64 root_objectid, u64 ref_generation,
                        u64 owner, u64 owner_offset,
                        u64 empty_size, u64 hint_byte,
-                       u64 search_end, struct btrfs_key *ins, int data);
+                       u64 search_end, struct btrfs_key *ins, u64 data);
 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct extent_buffer *buf);
 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fe4fe709c312..95aee5a29375 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -17,6 +17,7 @@
  */
 #include <linux/sched.h>
 #include <linux/pagemap.h>
+#include <linux/writeback.h>
 #include "hash.h"
 #include "crc32c.h"
 #include "ctree.h"
@@ -1058,6 +1059,26 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
         }
 }
 
+static u64 reduce_alloc_profile(u64 flags)
+{
+        if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
+            (flags & (BTRFS_BLOCK_GROUP_RAID1 |
+                      BTRFS_BLOCK_GROUP_RAID10)))
+                flags &= ~BTRFS_BLOCK_GROUP_DUP;
+
+        if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
+            (flags & BTRFS_BLOCK_GROUP_RAID10))
+                flags &= ~BTRFS_BLOCK_GROUP_RAID1;
+
+        if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
+            ((flags & BTRFS_BLOCK_GROUP_RAID1) |
+             (flags & BTRFS_BLOCK_GROUP_RAID10) |
+             (flags & BTRFS_BLOCK_GROUP_DUP)))
+                flags &= ~BTRFS_BLOCK_GROUP_RAID0;
+        return flags;
+}
+
+
 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
                           struct btrfs_root *extent_root, u64 alloc_bytes,
                           u64 flags)
@@ -1068,6 +1089,8 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
         u64 num_bytes;
         int ret;
 
+        flags = reduce_alloc_profile(flags);
+
         space_info = __find_space_info(extent_root->fs_info, flags);
         if (!space_info) {
                 ret = update_space_info(extent_root->fs_info, flags,
@@ -1684,6 +1707,7 @@ enospc:
 error:
         return ret;
 }
+
 /*
  * finds a free extent and does all the dirty work required for allocation
  * returns the key for the extent through ins, and a tree buffer for
@@ -1697,7 +1721,7 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
                        u64 root_objectid, u64 ref_generation,
                        u64 owner, u64 owner_offset,
                        u64 empty_size, u64 hint_byte,
-                       u64 search_end, struct btrfs_key *ins, int data)
+                       u64 search_end, struct btrfs_key *ins, u64 data)
 {
         int ret;
         int pending_ret;
@@ -1727,6 +1751,7 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
         }
 again:
+        data = reduce_alloc_profile(data);
         if (root->ref_cows) {
                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
@@ -1752,6 +1777,9 @@ again:
                 num_bytes = max(num_bytes, min_alloc_size);
                 goto again;
         }
+        if (ret) {
+                printk("allocation failed flags %Lu\n", data);
+        }
         BUG_ON(ret);
         if (ret)
                 return ret;
@@ -2274,8 +2302,6 @@ static int noinline relocate_inode_pages(struct inode *inode, u64 start,
 {
         u64 page_start;
         u64 page_end;
-        u64 delalloc_start;
-        u64 existing_delalloc;
         unsigned long last_index;
         unsigned long i;
         struct page *page;
@@ -2293,7 +2319,6 @@ static int noinline relocate_inode_pages(struct inode *inode, u64 start,
         ra_pages = BTRFS_I(inode)->root->fs_info->bdi.ra_pages;
 
         file_ra_state_init(ra, inode->i_mapping);
-        kfree(ra);
 
         for (; i <= last_index; i++) {
                 if (total_read % ra_pages == 0) {
@@ -2313,26 +2338,30 @@ static int noinline relocate_inode_pages(struct inode *inode, u64 start,
                                 goto out_unlock;
                         }
                 }
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
+                ClearPageDirty(page);
+#else
+                cancel_dirty_page(page, PAGE_CACHE_SIZE);
+#endif
+                wait_on_page_writeback(page);
+                set_page_extent_mapped(page);
                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 
                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 
-                delalloc_start = page_start;
-                existing_delalloc = count_range_bits(io_tree,
-                                             &delalloc_start, page_end,
-                                             PAGE_CACHE_SIZE, EXTENT_DELALLOC);
-
+                set_page_dirty(page);
                 set_extent_delalloc(io_tree, page_start,
                                     page_end, GFP_NOFS);
 
                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
-                set_page_dirty(page);
                 unlock_page(page);
                 page_cache_release(page);
+                balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
         }
 
 out_unlock:
+        kfree(ra);
         mutex_unlock(&inode->i_mutex);
         return 0;
 }
@@ -2397,8 +2426,6 @@ static int noinline relocate_one_reference(struct btrfs_root *extent_root,
                         goto out;
                 }
                 relocate_inode_pages(inode, ref_offset, extent_key->offset);
-                /* FIXME, data=ordered will help get rid of this */
-                filemap_fdatawrite(inode->i_mapping);
                 iput(inode);
                 mutex_lock(&extent_root->fs_info->fs_mutex);
         } else {
@@ -2486,6 +2513,47 @@ out:
         return ret;
 }
 
+static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
+{
+        u64 num_devices;
+        u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
+                BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
+
+        num_devices = btrfs_super_num_devices(&root->fs_info->super_copy);
+        if (num_devices == 1) {
+                stripped |= BTRFS_BLOCK_GROUP_DUP;
+                stripped = flags & ~stripped;
+
+                /* turn raid0 into single device chunks */
+                if (flags & BTRFS_BLOCK_GROUP_RAID0)
+                        return stripped;
+
+                /* turn mirroring into duplication */
+                if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
+                             BTRFS_BLOCK_GROUP_RAID10))
+                        return stripped | BTRFS_BLOCK_GROUP_DUP;
+                return flags;
+        } else {
+                /* they already had raid on here, just return */
+                if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
+                    (flags & BTRFS_BLOCK_GROUP_RAID1)) {
+                }
+                if (flags & stripped)
+                        return flags;
+
+                stripped |= BTRFS_BLOCK_GROUP_DUP;
+                stripped = flags & ~stripped;
+
+                /* switch duplicated blocks with raid1 */
+                if (flags & BTRFS_BLOCK_GROUP_DUP)
+                        return stripped | BTRFS_BLOCK_GROUP_RAID1;
+
+                /* turn single device chunks into raid0 */
+                return stripped | BTRFS_BLOCK_GROUP_RAID0;
+        }
+        return flags;
+}
+
 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
 {
         struct btrfs_trans_handle *trans;
@@ -2494,6 +2562,7 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
         u64 cur_byte;
         u64 total_found;
         u64 shrink_last_byte;
+        u64 new_alloc_flags;
         struct btrfs_block_group_cache *shrink_block_group;
         struct btrfs_fs_info *info = root->fs_info;
         struct btrfs_key key;
@@ -2511,17 +2580,20 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
 
         shrink_block_group->space_info->total_bytes -=
                 shrink_block_group->key.offset;
-printk("shrink_extent_tree %Lu -> %Lu type %Lu\n", shrink_start, shrink_last_byte, shrink_block_group->flags);
         path = btrfs_alloc_path();
         root = root->fs_info->extent_root;
         path->reada = 2;
 
 again:
-        trans = btrfs_start_transaction(root, 1);
-        do_chunk_alloc(trans, root->fs_info->extent_root,
+        if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
+                trans = btrfs_start_transaction(root, 1);
+                new_alloc_flags = update_block_group_flags(root,
+                                                   shrink_block_group->flags);
+                do_chunk_alloc(trans, root->fs_info->extent_root,
                         btrfs_block_group_used(&shrink_block_group->item) +
-                        2 * 1024 * 1024, shrink_block_group->flags);
-        btrfs_end_transaction(trans, root);
+                        2 * 1024 * 1024, new_alloc_flags);
+                btrfs_end_transaction(trans, root);
+        }
         shrink_block_group->ro = 1;
 
         total_found = 0;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1a74b5018699..994834474590 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2864,6 +2864,15 @@ int btrfs_defrag_file(struct file *file) {
                                 goto out_unlock;
                         }
                 }
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
+                ClearPageDirty(page);
+#else
+                cancel_dirty_page(page, PAGE_CACHE_SIZE);
+#endif
+                wait_on_page_writeback(page);
+                set_page_extent_mapped(page);
+
                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 
@@ -3105,6 +3114,8 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_resize(root, (void __user *)arg);
         case BTRFS_IOC_ADD_DEV:
                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
+        case BTRFS_IOC_BALANCE:
+                return btrfs_balance(root->fs_info->dev_root);
         }
 
         return -ENOTTY;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b93c15aa17db..6476ecbf132e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -869,6 +869,107 @@ out:
         return 0;
 }
 
+static u64 div_factor(u64 num, int factor)
+{
+        if (factor == 10)
+                return num;
+        num *= factor;
+        do_div(num, 10);
+        return num;
+}
+
+
+int btrfs_balance(struct btrfs_root *dev_root)
+{
+        int ret;
+        struct list_head *cur;
+        struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
+        struct btrfs_device *device;
+        u64 old_size;
+        u64 size_to_free;
+        struct btrfs_path *path;
+        struct btrfs_key key;
+        struct btrfs_chunk *chunk;
+        struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
+        struct btrfs_trans_handle *trans;
+        struct btrfs_key found_key;
+
+
+        dev_root = dev_root->fs_info->dev_root;
+
+        mutex_lock(&dev_root->fs_info->fs_mutex);
+        /* step one make some room on all the devices */
+        list_for_each(cur, devices) {
+                device = list_entry(cur, struct btrfs_device, dev_list);
+                old_size = device->total_bytes;
+                size_to_free = div_factor(old_size, 1);
+                size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
+                if (device->total_bytes - device->bytes_used > size_to_free)
+                        continue;
+
+                ret = btrfs_shrink_device(device, old_size - size_to_free);
+                BUG_ON(ret);
+
+                trans = btrfs_start_transaction(dev_root, 1);
+                BUG_ON(!trans);
+
+                ret = btrfs_grow_device(trans, device, old_size);
+                BUG_ON(ret);
+
+                btrfs_end_transaction(trans, dev_root);
+        }
+
+        /* step two, relocate all the chunks */
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+
+        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+        key.offset = (u64)-1;
+        key.type = BTRFS_CHUNK_ITEM_KEY;
+
+        while(1) {
+                ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
+                if (ret < 0)
+                        goto error;
+
+                /*
+                 * this shouldn't happen, it means the last relocate
+                 * failed
+                 */
+                if (ret == 0)
+                        break;
+
+                ret = btrfs_previous_item(chunk_root, path, 0,
+                                          BTRFS_CHUNK_ITEM_KEY);
+                if (ret) {
+                        break;
+                }
+                btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+                                      path->slots[0]);
+                if (found_key.objectid != key.objectid)
+                        break;
+                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)
+                        break;
+
+                ret = btrfs_relocate_chunk(chunk_root,
+                                           chunk_root->root_key.objectid,
+                                           found_key.objectid,
+                                           found_key.offset);
+                BUG_ON(ret);
+                btrfs_release_path(chunk_root, path);
+        }
+        ret = 0;
+error:
+        btrfs_free_path(path);
+        mutex_unlock(&dev_root->fs_info->fs_mutex);
+        return ret;
+}
+
 /*
  * shrinking a device means finding all of the device extents past
  * the new size, and then following the back refs to the chunks.
@@ -985,15 +1086,6 @@ int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
         return 0;
 }
 
-static u64 div_factor(u64 num, int factor)
-{
-        if (factor == 10)
-                return num;
-        num *= factor;
-        do_div(num, 10);
-        return num;
-}
-
 static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
                                int sub_stripes)
 {
@@ -1040,6 +1132,11 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
         int stripe_len = 64 * 1024;
         struct btrfs_key key;
 
+        if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
+            (type & BTRFS_BLOCK_GROUP_DUP)) {
+                WARN_ON(1);
+                type &= ~BTRFS_BLOCK_GROUP_DUP;
+        }
         dev_list = &extent_root->fs_info->fs_devices->alloc_list;
         if (list_empty(dev_list))
                 return -ENOSPC;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 6f173450378b..3f9a17f2e41b 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -134,4 +134,5 @@ struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
                                        u8 *uuid);
 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
 int btrfs_init_new_device(struct btrfs_root *root, char *path);
+int btrfs_balance(struct btrfs_root *dev_root);
 #endif