Btrfs: initial move to kernel module land

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

1 files changed, 205 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
new file mode 100644
index 000000000000..4ae76044aeab
--- /dev/null
+++ b/fs/btrfs/super.c
@@ -0,0 +1,205 @@
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+#include "ctree.h"
+
+#define BTRFS_SUPER_MAGIC 0x9123682E
+#if 0
+/* some random number */
+
+static struct super_operations ramfs_ops;
+static struct inode_operations ramfs_dir_inode_operations;
+
+static struct backing_dev_info ramfs_backing_dev_info = {
+        .ra_pages       = 0,    /* No readahead */
+        .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK |
+                          BDI_CAP_MAP_DIRECT | BDI_CAP_MAP_COPY |
+                          BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP,
+};
+
+struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev)
+{
+        struct inode * inode = new_inode(sb);
+
+        if (inode) {
+                inode->i_mode = mode;
+                inode->i_uid = current->fsuid;
+                inode->i_gid = current->fsgid;
+                inode->i_blocks = 0;
+                inode->i_mapping->a_ops = &ramfs_aops;
+                inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;
+                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+                switch (mode & S_IFMT) {
+                default:
+                        init_special_inode(inode, mode, dev);
+                        break;
+                case S_IFREG:
+                        inode->i_op = &ramfs_file_inode_operations;
+                        inode->i_fop = &ramfs_file_operations;
+                        break;
+                case S_IFDIR:
+                        inode->i_op = &ramfs_dir_inode_operations;
+                        inode->i_fop = &simple_dir_operations;
+
+                        /* directory inodes start off with i_nlink == 2 (for "." entry) */
+                        inc_nlink(inode);
+                        break;
+                case S_IFLNK:
+                        inode->i_op = &page_symlink_inode_operations;
+                        break;
+                }
+        }
+        return inode;
+}
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+/* SMP-safe */
+static int
+ramfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+{
+        struct inode * inode = ramfs_get_inode(dir->i_sb, mode, dev);
+        int error = -ENOSPC;
+
+        if (inode) {
+                if (dir->i_mode & S_ISGID) {
+                        inode->i_gid = dir->i_gid;
+                        if (S_ISDIR(mode))
+                                inode->i_mode |= S_ISGID;
+                }
+                d_instantiate(dentry, inode);
+                dget(dentry);   /* Extra count - pin the dentry in core */
+                error = 0;
+                dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+        }
+        return error;
+}
+
+static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
+{
+        int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+        if (!retval)
+                inc_nlink(dir);
+        return retval;
+}
+
+static int ramfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
+{
+        return ramfs_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
+{
+        struct inode *inode;
+        int error = -ENOSPC;
+
+        inode = ramfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
+        if (inode) {
+                int l = strlen(symname)+1;
+                error = page_symlink(inode, symname, l);
+                if (!error) {
+                        if (dir->i_mode & S_ISGID)
+                                inode->i_gid = dir->i_gid;
+                        d_instantiate(dentry, inode);
+                        dget(dentry);
+                        dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+                } else
+                        iput(inode);
+        }
+        return error;
+}
+
+static struct inode_operations ramfs_dir_inode_operations = {
+        .create         = ramfs_create,
+        .lookup         = simple_lookup,
+        .link           = simple_link,
+        .unlink         = simple_unlink,
+        .symlink        = ramfs_symlink,
+        .mkdir          = ramfs_mkdir,
+        .rmdir          = simple_rmdir,
+        .mknod          = ramfs_mknod,
+        .rename         = simple_rename,
+};
+#endif
+
+struct inode *btrfs_get_inode(struct super_block *sb, int mode, dev_t dev)
+{
+        struct inode * inode = new_inode(sb);
+
+        if (inode) {
+                inode->i_mode = mode;
+                inode->i_uid = current->fsuid;
+                inode->i_gid = current->fsgid;
+                inode->i_blocks = 0;
+                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+        }
+        return inode;
+}
+
+static struct super_operations btrfs_ops = {
+        .statfs         = simple_statfs,
+        .drop_inode     = generic_delete_inode,
+};
+
+static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
+{
+        struct inode * inode;
+        struct dentry * root;
+
+        sb->s_maxbytes = MAX_LFS_FILESIZE;
+        sb->s_blocksize = PAGE_CACHE_SIZE;
+        sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+        sb->s_magic = BTRFS_SUPER_MAGIC;
+        sb->s_op = &btrfs_ops;
+        sb->s_time_gran = 1;
+        inode = btrfs_get_inode(sb, S_IFDIR | 0755, 0);
+        if (!inode)
+                return -ENOMEM;
+
+        root = d_alloc_root(inode);
+        if (!root) {
+                iput(inode);
+                return -ENOMEM;
+        }
+        sb->s_root = root;
+        return 0;
+}
+
+static int btrfs_get_sb(struct file_system_type *fs_type,
+        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
+{
+        return get_sb_bdev(fs_type, flags, dev_name, data,
+                           btrfs_fill_super, mnt);
+}
+
+static struct file_system_type btrfs_fs_type = {
+        .owner          = THIS_MODULE,
+        .name           = "btrfs",
+        .get_sb         = btrfs_get_sb,
+        .kill_sb        = kill_block_super,
+        .fs_flags       = FS_REQUIRES_DEV,
+};
+
+static int __init init_btrfs_fs(void)
+{
+        printk("btrfs loaded!\n");
+        return register_filesystem(&btrfs_fs_type);
+}
+
+static void __exit exit_btrfs_fs(void)
+{
+        unregister_filesystem(&btrfs_fs_type);
+        printk("btrfs unloaded\n");
+}
+
+module_init(init_btrfs_fs)
+module_exit(exit_btrfs_fs)
+
+MODULE_LICENSE("GPL");