Btrfs: Add support for multiple devices per filesystem

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

1 files changed, 91 insertions, 6 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 88e21bdbc478..8e37fa120cc8 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -28,6 +28,7 @@
 #include "disk-io.h"
 #include "transaction.h"
 #include "btrfs_inode.h"
+#include "volumes.h"
 #include "print-tree.h"
 
 #if 0
@@ -234,6 +235,19 @@ static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
         return 0;
 }
 
+static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio)
+{
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        u64 offset;
+        offset = bio->bi_sector << 9;
+        if (offset == BTRFS_SUPER_INFO_OFFSET) {
+                bio->bi_bdev = root->fs_info->sb->s_bdev;
+                submit_bio(rw, bio);
+                return 0;
+        }
+        return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio);
+}
+
 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 {
         struct extent_io_tree *tree;
@@ -345,6 +359,23 @@ int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize)
         return ret;
 }
 
+static int close_all_devices(struct btrfs_fs_info *fs_info)
+{
+        struct list_head *list;
+        struct list_head *next;
+        struct btrfs_device *device;
+
+        list = &fs_info->devices;
+        while(!list_empty(list)) {
+                next = list->next;
+                list_del(next);
+                device = list_entry(next, struct btrfs_device, dev_list);
+                kfree(device->name);
+                kfree(device);
+        }
+        return 0;
+}
+
 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
                                       u32 blocksize)
 {
@@ -420,6 +451,8 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         root->leafsize = leafsize;
         root->stripesize = stripesize;
         root->ref_cows = 0;
+        root->track_dirty = 0;
+
         root->fs_info = fs_info;
         root->objectid = objectid;
         root->last_trans = 0;
@@ -427,6 +460,8 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         root->last_inode_alloc = 0;
         root->name = NULL;
         root->in_sysfs = 0;
+
+        INIT_LIST_HEAD(&root->dirty_list);
         memset(&root->root_key, 0, sizeof(root->root_key));
         memset(&root->root_item, 0, sizeof(root->root_item));
         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
@@ -634,6 +669,10 @@ struct btrfs_root *open_ctree(struct super_block *sb)
                                                GFP_NOFS);
         struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
                                                 GFP_NOFS);
+        struct btrfs_root *chunk_root = kmalloc(sizeof(struct btrfs_root),
+                                                GFP_NOFS);
+        struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
+                                              GFP_NOFS);
         int ret;
         int err = -EIO;
         struct btrfs_super_block *disk_super;
@@ -657,6 +696,12 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         fs_info->last_trans_committed = 0;
         fs_info->tree_root = tree_root;
         fs_info->extent_root = extent_root;
+        fs_info->chunk_root = chunk_root;
+        fs_info->dev_root = dev_root;
+        INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
+        INIT_LIST_HEAD(&fs_info->devices);
+        btrfs_mapping_init(&fs_info->mapping_tree);
+        fs_info->last_device = &fs_info->devices;
         fs_info->sb = sb;
         fs_info->throttles = 0;
         fs_info->mount_opt = 0;
@@ -714,12 +759,12 @@ struct btrfs_root *open_ctree(struct super_block *sb)
                 goto fail_iput;
         }
 #endif
-        __setup_root(512, 512, 512, 512, tree_root,
+        __setup_root(4096, 4096, 4096, 4096, tree_root,
                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
 
         fs_info->sb_buffer = read_tree_block(tree_root,
                                              BTRFS_SUPER_INFO_OFFSET,
-                                             512);
+                                             4096);
 
         if (!fs_info->sb_buffer)
                 goto fail_iput;
@@ -730,6 +775,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         read_extent_buffer(fs_info->sb_buffer, fs_info->fsid,
                            (unsigned long)btrfs_super_fsid(fs_info->sb_buffer),
                            BTRFS_FSID_SIZE);
+
         disk_super = &fs_info->super_copy;
         if (!btrfs_super_root(disk_super))
                 goto fail_sb_buffer;
@@ -753,23 +799,47 @@ struct btrfs_root *open_ctree(struct super_block *sb)
                 goto fail_sb_buffer;
         }
 
+        mutex_lock(&fs_info->fs_mutex);
+        ret = btrfs_read_sys_array(tree_root);
+        BUG_ON(ret);
+
+        blocksize = btrfs_level_size(tree_root,
+                                     btrfs_super_chunk_root_level(disk_super));
+
+        __setup_root(nodesize, leafsize, sectorsize, stripesize,
+                     chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
+
+        chunk_root->node = read_tree_block(chunk_root,
+                                           btrfs_super_chunk_root(disk_super),
+                                           blocksize);
+        BUG_ON(!chunk_root->node);
+
+        ret = btrfs_read_chunk_tree(chunk_root);
+        BUG_ON(ret);
+
         blocksize = btrfs_level_size(tree_root,
                                      btrfs_super_root_level(disk_super));
 
+
         tree_root->node = read_tree_block(tree_root,
                                           btrfs_super_root(disk_super),
                                           blocksize);
         if (!tree_root->node)
                 goto fail_sb_buffer;
 
-        mutex_lock(&fs_info->fs_mutex);
 
         ret = find_and_setup_root(tree_root, fs_info,
                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
-        if (ret) {
-                mutex_unlock(&fs_info->fs_mutex);
+        if (ret)
                 goto fail_tree_root;
-        }
+        extent_root->track_dirty = 1;
+
+        ret = find_and_setup_root(tree_root, fs_info,
+                                  BTRFS_DEV_TREE_OBJECTID, dev_root);
+        dev_root->track_dirty = 1;
+
+        if (ret)
+                goto fail_extent_root;
 
         btrfs_read_block_groups(extent_root);
 
@@ -777,7 +847,10 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         mutex_unlock(&fs_info->fs_mutex);
         return tree_root;
 
+fail_extent_root:
+        free_extent_buffer(extent_root->node);
 fail_tree_root:
+        mutex_unlock(&fs_info->fs_mutex);
         free_extent_buffer(tree_root->node);
 fail_sb_buffer:
         free_extent_buffer(fs_info->sb_buffer);
@@ -874,6 +947,12 @@ int close_ctree(struct btrfs_root *root)
         if (fs_info->tree_root->node)
                 free_extent_buffer(fs_info->tree_root->node);
 
+        if (root->fs_info->chunk_root->node);
+                free_extent_buffer(root->fs_info->chunk_root->node);
+
+        if (root->fs_info->dev_root->node);
+                free_extent_buffer(root->fs_info->dev_root->node);
+
         free_extent_buffer(fs_info->sb_buffer);
 
         btrfs_free_block_groups(root->fs_info);
@@ -901,8 +980,13 @@ int close_ctree(struct btrfs_root *root)
                 kfree(hasher);
         }
 #endif
+        close_all_devices(fs_info);
+        btrfs_mapping_tree_free(&fs_info->mapping_tree);
+
         kfree(fs_info->extent_root);
         kfree(fs_info->tree_root);
+        kfree(fs_info->chunk_root);
+        kfree(fs_info->dev_root);
         return 0;
 }
 
@@ -1016,4 +1100,5 @@ int btrfs_read_buffer(struct extent_buffer *buf)
 
 static struct extent_io_ops btree_extent_io_ops = {
         .writepage_io_hook = btree_writepage_io_hook,
+        .submit_bio_hook = btree_submit_bio_hook,
 };