btrfs_create, btrfs_write_super, btrfs_sync_fs

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

10 files changed, 201 insertions, 47 deletions

diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index c5d67bbd4d90..4b5bd05de94f 100644
--- a/fs/btrfs/TODO
+++ b/fs/btrfs/TODO
@@ -3,6 +3,7 @@
 * Fix ENOSPC handling
 * make a real mkfs and superblock
 * Do checksumming
+* Use a real check instead of mark_buffer_dirty
 * Define FS objects in terms of different item types
 * Add block mapping tree (simple dm layer)
 * Add simple tree locking (semaphore per tree)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e690e2bb47d2..052434a328ec 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -39,7 +39,7 @@ static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
         struct buffer_head *cow;
         struct btrfs_node *cow_node;
 
-        if (!buffer_dirty(buf)) {
+        if (buffer_dirty(buf)) {
                 *cow_ret = buf;
                 return 0;
         }
@@ -48,6 +48,7 @@ static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
         memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize);
         btrfs_set_header_blocknr(&cow_node->header, cow->b_blocknr);
         *cow_ret = cow;
+        mark_buffer_dirty(cow);
         btrfs_inc_ref(trans, root, buf);
         if (buf == root->node) {
                 root->node = cow;
@@ -58,7 +59,7 @@ static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
         } else {
                 btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
                                         cow->b_blocknr);
-                BUG_ON(!buffer_dirty(parent));
+                mark_buffer_dirty(parent);
                 btrfs_free_extent(trans, root, buf->b_blocknr, 1, 1);
         }
         btrfs_block_release(root, buf);
@@ -362,7 +363,7 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
                         memcpy(&parent->ptrs[pslot + 1].key,
                                 &right->ptrs[0].key,
                                 sizeof(struct btrfs_disk_key));
-                        BUG_ON(!buffer_dirty(parent_buf));
+                        mark_buffer_dirty(parent_buf);
                 }
         }
         if (btrfs_header_nritems(&mid->header) == 1) {
@@ -398,7 +399,7 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
                 /* update the parent key to reflect our changes */
                 memcpy(&parent->ptrs[pslot].key, &mid->ptrs[0].key,
                        sizeof(struct btrfs_disk_key));
-                BUG_ON(!buffer_dirty(parent_buf));
+                mark_buffer_dirty(parent_buf);
         }
 
         /* update the path */
@@ -539,7 +540,7 @@ static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root
                         break;
                 t = btrfs_buffer_node(path->nodes[i]);
                 memcpy(&t->ptrs[tslot].key, key, sizeof(*key));
-                BUG_ON(!buffer_dirty(path->nodes[i]));
+                mark_buffer_dirty(path->nodes[i]);
                 if (tslot != 0)
                         break;
         }
@@ -583,8 +584,8 @@ static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
         }
         btrfs_set_header_nritems(&src->header, src_nritems - push_items);
         btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
-        BUG_ON(!buffer_dirty(src_buf));
-        BUG_ON(!buffer_dirty(dst_buf));
+        mark_buffer_dirty(src_buf);
+        mark_buffer_dirty(dst_buf);
         return ret;
 }
 
@@ -631,8 +632,8 @@ static int balance_node_right(struct btrfs_trans_handle *trans, struct
         btrfs_set_header_nritems(&src->header, src_nritems - push_items);
         btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
 
-        BUG_ON(!buffer_dirty(src_buf));
-        BUG_ON(!buffer_dirty(dst_buf));
+        mark_buffer_dirty(src_buf);
+        mark_buffer_dirty(dst_buf);
         return ret;
 }
 
@@ -669,6 +670,9 @@ static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
                 lower_key = &lower->ptrs[0].key;
         memcpy(&c->ptrs[0].key, lower_key, sizeof(struct btrfs_disk_key));
         btrfs_set_node_blockptr(c, 0, path->nodes[level - 1]->b_blocknr);
+
+        mark_buffer_dirty(t);
+
         /* the super has an extra ref to root->node */
         btrfs_block_release(root, root->node);
         root->node = t;
@@ -708,7 +712,7 @@ static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
         memcpy(&lower->ptrs[slot].key, key, sizeof(struct btrfs_disk_key));
         btrfs_set_node_blockptr(lower, slot, blocknr);
         btrfs_set_header_nritems(&lower->header, nritems + 1);
-        BUG_ON(!buffer_dirty(path->nodes[level]));
+        mark_buffer_dirty(path->nodes[level]);
         return 0;
 }
 
@@ -755,7 +759,8 @@ static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
         btrfs_set_header_nritems(&c->header, mid);
         ret = 0;
 
-        BUG_ON(!buffer_dirty(t));
+        mark_buffer_dirty(t);
+        mark_buffer_dirty(split_buffer);
         wret = insert_ptr(trans, root, path, &split->ptrs[0].key,
                           split_buffer->b_blocknr, path->slots[level + 1] + 1,
                           level + 1);
@@ -886,11 +891,11 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
         left_nritems -= push_items;
         btrfs_set_header_nritems(&left->header, left_nritems);
 
-        BUG_ON(!buffer_dirty(left_buf));
-        BUG_ON(!buffer_dirty(right_buf));
+        mark_buffer_dirty(left_buf);
+        mark_buffer_dirty(right_buf);
         memcpy(&upper_node->ptrs[slot + 1].key,
                 &right->items[0].key, sizeof(struct btrfs_disk_key));
-        BUG_ON(!buffer_dirty(upper));
+        mark_buffer_dirty(upper);
 
         /* then fixup the leaf pointer in the path */
         if (path->slots[0] >= left_nritems) {
@@ -1004,8 +1009,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                 push_space = btrfs_item_offset(right->items + i);
         }
 
-        BUG_ON(!buffer_dirty(t));
-        BUG_ON(!buffer_dirty(right_buf));
+        mark_buffer_dirty(t);
+        mark_buffer_dirty(right_buf);
 
         wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1);
         if (wret)
@@ -1115,8 +1120,8 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
                           right_buffer->b_blocknr, path->slots[1] + 1, 1);
         if (wret)
                 ret = wret;
-        BUG_ON(!buffer_dirty(right_buffer));
-        BUG_ON(!buffer_dirty(l_buf));
+        mark_buffer_dirty(right_buffer);
+        mark_buffer_dirty(l_buf);
         BUG_ON(path->slots[0] != slot);
         if (mid <= slot) {
                 btrfs_block_release(root, path->nodes[0]);
@@ -1202,12 +1207,12 @@ int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
         btrfs_set_item_offset(leaf->items + slot, data_end - data_size);
         btrfs_set_item_size(leaf->items + slot, data_size);
         btrfs_set_header_nritems(&leaf->header, nritems + 1);
+        mark_buffer_dirty(leaf_buf);
 
         ret = 0;
         if (slot == 0)
                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
 
-        BUG_ON(!buffer_dirty(leaf_buf));
         if (btrfs_leaf_free_space(root, leaf) < 0)
                 BUG();
         check_leaf(root, path, 0);
@@ -1233,6 +1238,7 @@ int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
                 ptr = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
                                      path.slots[0], u8);
                 memcpy(ptr, data, data_size);
+                mark_buffer_dirty(path.nodes[0]);
         }
         btrfs_release_path(root, &path);
         return ret;
@@ -1273,7 +1279,7 @@ static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                 if (wret)
                         ret = wret;
         }
-        BUG_ON(!buffer_dirty(parent));
+        mark_buffer_dirty(parent);
         return ret;
 }
 
@@ -1368,8 +1374,11 @@ int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                                 if (wret)
                                         ret = wret;
                         } else {
+                                mark_buffer_dirty(leaf_buf);
                                 btrfs_block_release(root, leaf_buf);
                         }
+                } else {
+                        mark_buffer_dirty(leaf_buf);
                 }
         }
         return ret;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4c19a3f12afd..983e3cc9ae9f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -833,7 +833,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
                          btrfs_root_item *item, struct btrfs_key *key);
 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
-                          *root, char *name, int name_len, u64 dir, u64
+                          *root, const char *name, int name_len, u64 dir, u64
                           objectid, u8 type);
 int btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
                           *root, struct btrfs_path *path, u64 dir,
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index 75d6e373e98d..f81cbcc83b66 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -5,7 +5,7 @@
 #include "transaction.h"
 
 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
-                          *root, char *name, int name_len, u64 dir, u64
+                          *root, const char *name, int name_len, u64 dir, u64
                           objectid, u8 type)
 {
         int ret = 0;
@@ -35,6 +35,7 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
         btrfs_set_dir_name_len(dir_item, name_len);
         name_ptr = (char *)(dir_item + 1);
         memcpy(name_ptr, name, name_len);
+        mark_buffer_dirty(path.nodes[0]);
 out:
         btrfs_release_path(root, &path);
         return ret;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9cacca0c525c..8e1dcda0839c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -145,19 +145,20 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root)
 {
-        return 0;
-#if 0
-        int ret;
-        btrfs_set_super_root(s, root->fs_info->tree_root->node->b_blocknr);
-
-        ret = pwrite(root->fs_info->fp, s, sizeof(*s),
-                     BTRFS_SUPER_INFO_OFFSET);
-        if (ret != sizeof(*s)) {
-                fprintf(stderr, "failed to write new super block err %d\n", ret);
-                return ret;
+        struct buffer_head *bh = root->fs_info->sb_buffer;
+        btrfs_set_super_root(root->fs_info->disk_super,
+                             root->fs_info->tree_root->node->b_blocknr);
+        lock_buffer(bh);
+        clear_buffer_dirty(bh);
+        bh->b_end_io = end_buffer_write_sync;
+        get_bh(bh);
+        submit_bh(WRITE, bh);
+        wait_on_buffer(bh);
+        if (!buffer_uptodate(bh)) {
+                WARN_ON(1);
+                return -EIO;
         }
         return 0;
-#endif
 }
 
 int close_ctree(struct btrfs_root *root)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e3af2c035687..2818f1c57170 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -49,6 +49,7 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
         item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item);
         refs = btrfs_extent_refs(item);
         btrfs_set_extent_refs(item, refs + 1);
+        mark_buffer_dirty(path.nodes[0]);
 
         btrfs_release_path(root->fs_info->extent_root, &path);
         finish_current_insert(trans, root->fs_info->extent_root);
@@ -103,7 +104,7 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
                                btrfs_root *root)
 {
-        unsigned long gang[8];
+        struct buffer_head *gang[8];
         u64 first = 0;
         int ret;
         int i;
@@ -116,13 +117,15 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
                 if (!ret)
                         break;
                 if (!first)
-                        first = gang[0];
+                        first = gang[0]->b_blocknr;
                 for (i = 0; i < ret; i++) {
                         radix_tree_delete(&root->fs_info->pinned_radix,
-                                          gang[i]);
+                                          gang[i]->b_blocknr);
+                        brelse(gang[i]);
                 }
         }
-        root->fs_info->last_insert.objectid = first;
+        if (root->fs_info->last_insert.objectid > first)
+                root->fs_info->last_insert.objectid = first;
         root->fs_info->last_insert.offset = 0;
         return 0;
 }
@@ -161,8 +164,10 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
 static int pin_down_block(struct btrfs_root *root, u64 blocknr, int tag)
 {
         int err;
+        struct buffer_head *bh = sb_getblk(root->fs_info->sb, blocknr);
+        BUG_ON(!bh);
         err = radix_tree_insert(&root->fs_info->pinned_radix,
-                                blocknr, (void *)blocknr);
+                                blocknr, bh);
         BUG_ON(err);
         if (err)
                 return err;
@@ -217,6 +222,7 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                 if (ret)
                         BUG();
         }
+        mark_buffer_dirty(path.nodes[0]);
         btrfs_release_path(extent_root, &path);
         finish_current_insert(trans, extent_root);
         return ret;
@@ -232,7 +238,7 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
         int ret;
         int wret;
         int err = 0;
-        unsigned long gang[4];
+        struct buffer_head *gang[4];
         int i;
         struct radix_tree_root *radix = &extent_root->fs_info->pinned_radix;
 
@@ -245,10 +251,12 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
                 if (!ret)
                         break;
                 for (i = 0; i < ret; i++) {
-                        radix_tree_tag_set(radix, gang[i], CTREE_EXTENT_PINNED);
-                        radix_tree_tag_clear(radix, gang[i],
+                        radix_tree_tag_set(radix, gang[i]->b_blocknr,
+                                           CTREE_EXTENT_PINNED);
+                        radix_tree_tag_clear(radix, gang[i]->b_blocknr,
                                              CTREE_EXTENT_PENDING_DEL);
-                        wret = __free_extent(trans, extent_root, gang[i], 1);
+                        wret = __free_extent(trans, extent_root,
+                                             gang[i]->b_blocknr, 1);
                         if (wret)
                                 err = wret;
                 }
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index c45aec258bd5..ad2d375b830d 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -108,6 +108,7 @@ int btrfs_insert_inode_map(struct btrfs_trans_handle *trans,
         inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
                                     path.slots[0], struct btrfs_inode_map_item);
         btrfs_cpu_key_to_disk(&inode_item->key, location);
+        mark_buffer_dirty(path.nodes[0]);
 out:
         btrfs_release_path(inode_root, &path);
         return ret;
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index a4554c007ef7..a821b5d1e233 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -55,6 +55,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
         slot = path.slots[0];
         memcpy(btrfs_item_ptr(l, slot, struct btrfs_root_item), item,
                 sizeof(*item));
+        mark_buffer_dirty(path.nodes[0]);
 out:
         btrfs_release_path(root, &path);
         return ret;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 620430825840..6080a8133d71 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -10,6 +10,7 @@
 #include <linux/backing-dev.h>
 #include "ctree.h"
 #include "disk-io.h"
+#include "transaction.h"
 
 #define BTRFS_SUPER_MAGIC 0x9123682E
 
@@ -357,6 +358,131 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
         return 0;
 }
 
+static void fill_inode_item(struct btrfs_inode_item *item,
+                            struct inode *inode)
+{
+        btrfs_set_inode_uid(item, inode->i_uid);
+        btrfs_set_inode_gid(item, inode->i_gid);
+        btrfs_set_inode_size(item, inode->i_size);
+        btrfs_set_inode_mode(item, inode->i_mode);
+        btrfs_set_inode_nlink(item, inode->i_nlink);
+        btrfs_set_timespec_sec(&item->atime, inode->i_atime.tv_sec);
+        btrfs_set_timespec_nsec(&item->atime, inode->i_atime.tv_nsec);
+        btrfs_set_timespec_sec(&item->mtime, inode->i_mtime.tv_sec);
+        btrfs_set_timespec_nsec(&item->mtime, inode->i_mtime.tv_nsec);
+        btrfs_set_timespec_sec(&item->ctime, inode->i_ctime.tv_sec);
+        btrfs_set_timespec_nsec(&item->ctime, inode->i_ctime.tv_nsec);
+        btrfs_set_inode_nblocks(item, inode->i_blocks);
+        btrfs_set_inode_generation(item, inode->i_generation);
+}
+
+static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
+                                     struct inode *dir, int mode)
+{
+        struct inode *inode;
+        struct btrfs_inode_item inode_item;
+        struct btrfs_root *root = btrfs_sb(dir->i_sb);
+        struct btrfs_key key;
+        int ret;
+        u64 objectid;
+
+        inode = new_inode(dir->i_sb);
+        if (!inode)
+                return ERR_PTR(-ENOMEM);
+
+        ret = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
+        BUG_ON(ret);
+
+        inode->i_uid = current->fsuid;
+        inode->i_gid = current->fsgid;
+        inode->i_mode = mode;
+        inode->i_ino = objectid;
+        inode->i_blocks = 0;
+        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
+        fill_inode_item(&inode_item, inode);
+
+
+        key.objectid = objectid;
+        key.flags = 0;
+        key.offset = 0;
+        btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+        ret = btrfs_insert_inode_map(trans, root, objectid, &key);
+        BUG_ON(ret);
+
+        ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
+        BUG_ON(ret);
+
+        insert_inode_hash(inode);
+        // FIXME mark_inode_dirty(inode)
+        return inode;
+}
+
+static int btrfs_add_link(struct btrfs_trans_handle *trans,
+                            struct dentry *dentry, struct inode *inode)
+{
+        int ret;
+        ret = btrfs_insert_dir_item(trans, btrfs_sb(inode->i_sb),
+                                    dentry->d_name.name, dentry->d_name.len,
+                                    dentry->d_parent->d_inode->i_ino,
+                                    inode->i_ino, 0);
+        BUG_ON(ret);
+        return ret;
+}
+
+static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
+                            struct dentry *dentry, struct inode *inode)
+{
+        int err = btrfs_add_link(trans, dentry, inode);
+        if (!err) {
+                d_instantiate(dentry, inode);
+                return 0;
+        }
+        inode_dec_link_count(inode);
+        iput(inode);
+        return err;
+}
+
+static int btrfs_create(struct inode *dir, struct dentry *dentry,
+                        int mode, struct nameidata *nd)
+{
+        struct btrfs_trans_handle *trans;
+        struct btrfs_root *root = btrfs_sb(dir->i_sb);
+        struct inode *inode;
+        int err;
+
+        trans = btrfs_start_transaction(root, 1);
+        inode = btrfs_new_inode(trans, dir, mode);
+        err = PTR_ERR(inode);
+        if (IS_ERR(inode))
+                return err;
+        // FIXME mark the inode dirty
+        err = btrfs_add_nondir(trans, dentry, inode);
+        dir->i_sb->s_dirt = 1;
+        btrfs_end_transaction(trans, root);
+        return err;
+}
+
+static void btrfs_write_super(struct super_block *sb)
+{
+        sb->s_dirt = 0;
+printk("btrfs write_super!\n");
+}
+
+static int btrfs_sync_fs(struct super_block *sb, int wait)
+{
+        struct btrfs_trans_handle *trans;
+        struct btrfs_root *root;
+        int ret;
+        sb->s_dirt = 0;
+        root = btrfs_sb(sb);
+        trans = btrfs_start_transaction(root, 1);
+        ret = btrfs_commit_transaction(trans, root);
+        sb->s_dirt = 0;
+        BUG_ON(ret);
+printk("btrfs sync_fs\n");
+        return 0;
+}
+
 static int btrfs_get_sb(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
@@ -377,10 +503,13 @@ static struct super_operations btrfs_super_ops = {
         .drop_inode     = generic_delete_inode,
         .put_super      = btrfs_put_super,
         .read_inode     = btrfs_read_locked_inode,
+        .write_super    = btrfs_write_super,
+        .sync_fs        = btrfs_sync_fs,
 };
 
 static struct inode_operations btrfs_dir_inode_operations = {
         .lookup         = btrfs_lookup,
+        .create         = btrfs_create,
 };
 
 static struct file_operations btrfs_dir_file_operations = {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 8dc1c170f10f..4903b47c9780 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -25,7 +25,7 @@ static int join_transaction(struct btrfs_root *root)
                 init_waitqueue_head(&cur_trans->writer_wait);
                 init_waitqueue_head(&cur_trans->commit_wait);
                 cur_trans->in_commit = 0;
-                cur_trans->use_count = 0;
+                cur_trans->use_count = 1;
                 cur_trans->commit_done = 0;
         }
         cur_trans->num_writers++;
@@ -56,7 +56,7 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans,
         struct btrfs_transaction *cur_trans;
         mutex_lock(&root->fs_info->trans_mutex);
         cur_trans = root->fs_info->running_transaction;
-        WARN_ON(cur_trans->num_writers <= 1);
+        WARN_ON(cur_trans->num_writers < 1);
         if (waitqueue_active(&cur_trans->writer_wait))
                 wake_up(&cur_trans->writer_wait);
         cur_trans->num_writers--;
@@ -155,10 +155,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
         cur_trans = root->fs_info->running_transaction;
         root->fs_info->running_transaction = NULL;
-        mutex_unlock(&root->fs_info->trans_mutex);
 
-        memcpy(&snap_key, &root->root_key, sizeof(snap_key));
-        root->root_key.offset++;
+        if (root->node != root->commit_root) {
+                memcpy(&snap_key, &root->root_key, sizeof(snap_key));
+                root->root_key.offset++;
+        }
+
+        mutex_unlock(&root->fs_info->trans_mutex);
 
         if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) {
                 btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr);