btrfs: use memdup_user()
[safe/jmp/linux-2.6] / fs / btrfs / ioctl.c
index 0b63c3c..9f135e8 100644 (file)
@@ -21,6 +21,7 @@
 #include <linux/buffer_head.h>
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/fsnotify.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
 #include <linux/time.h>
 #include <linux/string.h>
 #include <linux/smp_lock.h>
 #include <linux/backing-dev.h>
+#include <linux/mount.h>
 #include <linux/mpage.h>
+#include <linux/namei.h>
 #include <linux/swap.h>
 #include <linux/writeback.h>
 #include <linux/statfs.h>
 #include <linux/compat.h>
 #include <linux/bit_spinlock.h>
-#include <linux/version.h>
+#include <linux/security.h>
 #include <linux/xattr.h>
+#include <linux/vmalloc.h>
+#include "compat.h"
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
@@ -47,8 +52,9 @@
 
 
 
-static noinline int create_subvol(struct btrfs_root *root, char *name,
-                                 int namelen)
+static noinline int create_subvol(struct btrfs_root *root,
+                                 struct dentry *dentry,
+                                 char *name, int namelen)
 {
        struct btrfs_trans_handle *trans;
        struct btrfs_key key;
@@ -61,9 +67,10 @@ static noinline int create_subvol(struct btrfs_root *root, char *name,
        int err;
        u64 objectid;
        u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
+       u64 index = 0;
        unsigned long nr = 1;
 
-       ret = btrfs_check_free_space(root, 1, 0);
+       ret = btrfs_check_metadata_free_space(root);
        if (ret)
                goto fail_commit;
 
@@ -75,9 +82,8 @@ static noinline int create_subvol(struct btrfs_root *root, char *name,
        if (ret)
                goto fail;
 
-       leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
-                                     objectid, trans->transid, 0, 0,
-                                     0, 0);
+       leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
+                                     objectid, trans->transid, 0, 0, 0);
        if (IS_ERR(leaf)) {
                ret = PTR_ERR(leaf);
                goto fail;
@@ -99,13 +105,15 @@ static noinline int create_subvol(struct btrfs_root *root, char *name,
        inode_item->generation = cpu_to_le64(1);
        inode_item->size = cpu_to_le64(3);
        inode_item->nlink = cpu_to_le32(1);
-       inode_item->nblocks = cpu_to_le64(1);
+       inode_item->nbytes = cpu_to_le64(root->leafsize);
        inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 
        btrfs_set_root_bytenr(&root_item, leaf->start);
+       btrfs_set_root_generation(&root_item, trans->transid);
        btrfs_set_root_level(&root_item, 0);
        btrfs_set_root_refs(&root_item, 1);
        btrfs_set_root_used(&root_item, 0);
+       btrfs_set_root_last_snapshot(&root_item, 0);
 
        memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
        root_item.drop_level = 0;
@@ -128,37 +136,51 @@ static noinline int create_subvol(struct btrfs_root *root, char *name,
         * insert the directory item
         */
        key.offset = (u64)-1;
-       dir = root->fs_info->sb->s_root->d_inode;
-       ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
+       dir = dentry->d_parent->d_inode;
+       ret = btrfs_set_inode_index(dir, &index);
+       BUG_ON(ret);
+
+       ret = btrfs_insert_dir_item(trans, root,
                                    name, namelen, dir->i_ino, &key,
-                                   BTRFS_FT_DIR, 0);
+                                   BTRFS_FT_DIR, index);
        if (ret)
                goto fail;
 
-       ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
-                            name, namelen, objectid,
-                            root->fs_info->sb->s_root->d_inode->i_ino, 0);
-       if (ret)
-               goto fail;
+       btrfs_i_size_write(dir, dir->i_size + namelen * 2);
+       ret = btrfs_update_inode(trans, root, dir);
+       BUG_ON(ret);
+
+       /* add the backref first */
+       ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
+                                objectid, BTRFS_ROOT_BACKREF_KEY,
+                                root->root_key.objectid,
+                                dir->i_ino, index, name, namelen);
+
+       BUG_ON(ret);
+
+       /* now add the forward ref */
+       ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
+                                root->root_key.objectid, BTRFS_ROOT_REF_KEY,
+                                objectid,
+                                dir->i_ino, index, name, namelen);
+
+       BUG_ON(ret);
 
        ret = btrfs_commit_transaction(trans, root);
        if (ret)
                goto fail_commit;
 
-       new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
+       new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
        BUG_ON(!new_root);
 
        trans = btrfs_start_transaction(new_root, 1);
        BUG_ON(!trans);
 
-       ret = btrfs_create_subvol_root(new_root, trans, new_dirid,
+       ret = btrfs_create_subvol_root(trans, new_root, dentry, new_dirid,
                                       BTRFS_I(dir)->block_group);
        if (ret)
                goto fail;
 
-       /* Invalidate existing dcache entry for new subvolume. */
-       btrfs_invalidate_dcache_root(root, name, namelen);
-
 fail:
        nr = trans->blocks_used;
        err = btrfs_commit_transaction(trans, new_root);
@@ -169,22 +191,23 @@ fail_commit:
        return ret;
 }
 
-static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
+static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
+                          char *name, int namelen)
 {
        struct btrfs_pending_snapshot *pending_snapshot;
        struct btrfs_trans_handle *trans;
-       int ret;
+       int ret = 0;
        int err;
        unsigned long nr = 0;
 
        if (!root->ref_cows)
                return -EINVAL;
 
-       ret = btrfs_check_free_space(root, 1, 0);
+       ret = btrfs_check_metadata_free_space(root);
        if (ret)
                goto fail_unlock;
 
-       pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
+       pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
        if (!pending_snapshot) {
                ret = -ENOMEM;
                goto fail_unlock;
@@ -197,12 +220,12 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
        }
        memcpy(pending_snapshot->name, name, namelen);
        pending_snapshot->name[namelen] = '\0';
+       pending_snapshot->dentry = dentry;
        trans = btrfs_start_transaction(root, 1);
        BUG_ON(!trans);
        pending_snapshot->root = root;
        list_add(&pending_snapshot->list,
                 &trans->transaction->pending_snapshots);
-       ret = btrfs_update_inode(trans, root, root->inode);
        err = btrfs_commit_transaction(trans, root);
 
 fail_unlock:
@@ -210,7 +233,133 @@ fail_unlock:
        return ret;
 }
 
-int btrfs_defrag_file(struct file *file)
+/* copy of may_create in fs/namei.c() */
+static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
+{
+       if (child->d_inode)
+               return -EEXIST;
+       if (IS_DEADDIR(dir))
+               return -ENOENT;
+       return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+}
+
+/*
+ * Create a new subvolume below @parent.  This is largely modeled after
+ * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
+ * inside this filesystem so it's quite a bit simpler.
+ */
+static noinline int btrfs_mksubvol(struct path *parent, char *name,
+                                  int mode, int namelen,
+                                  struct btrfs_root *snap_src)
+{
+       struct dentry *dentry;
+       int error;
+
+       mutex_lock_nested(&parent->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+
+       dentry = lookup_one_len(name, parent->dentry, namelen);
+       error = PTR_ERR(dentry);
+       if (IS_ERR(dentry))
+               goto out_unlock;
+
+       error = -EEXIST;
+       if (dentry->d_inode)
+               goto out_dput;
+
+       if (!IS_POSIXACL(parent->dentry->d_inode))
+               mode &= ~current_umask();
+
+       error = mnt_want_write(parent->mnt);
+       if (error)
+               goto out_dput;
+
+       error = btrfs_may_create(parent->dentry->d_inode, dentry);
+       if (error)
+               goto out_drop_write;
+
+       /*
+        * Actually perform the low-level subvolume creation after all
+        * this VFS fuzz.
+        *
+        * Eventually we want to pass in an inode under which we create this
+        * subvolume, but for now all are under the filesystem root.
+        *
+        * Also we should pass on the mode eventually to allow creating new
+        * subvolume with specific mode bits.
+        */
+       if (snap_src) {
+               struct dentry *dir = dentry->d_parent;
+               struct dentry *test = dir->d_parent;
+               struct btrfs_path *path = btrfs_alloc_path();
+               int ret;
+               u64 test_oid;
+               u64 parent_oid = BTRFS_I(dir->d_inode)->root->root_key.objectid;
+
+               test_oid = snap_src->root_key.objectid;
+
+               ret = btrfs_find_root_ref(snap_src->fs_info->tree_root,
+                                         path, parent_oid, test_oid);
+               if (ret == 0)
+                       goto create;
+               btrfs_release_path(snap_src->fs_info->tree_root, path);
+
+               /* we need to make sure we aren't creating a directory loop
+                * by taking a snapshot of something that has our current
+                * subvol in its directory tree.  So, this loops through
+                * the dentries and checks the forward refs for each subvolume
+                * to see if is references the subvolume where we are
+                * placing this new snapshot.
+                */
+               while (1) {
+                       if (!test ||
+                           dir == snap_src->fs_info->sb->s_root ||
+                           test == snap_src->fs_info->sb->s_root ||
+                           test->d_inode->i_sb != snap_src->fs_info->sb) {
+                               break;
+                       }
+                       if (S_ISLNK(test->d_inode->i_mode)) {
+                               printk(KERN_INFO "Btrfs symlink in snapshot "
+                                      "path, failed\n");
+                               error = -EMLINK;
+                               btrfs_free_path(path);
+                               goto out_drop_write;
+                       }
+                       test_oid =
+                               BTRFS_I(test->d_inode)->root->root_key.objectid;
+                       ret = btrfs_find_root_ref(snap_src->fs_info->tree_root,
+                                 path, test_oid, parent_oid);
+                       if (ret == 0) {
+                               printk(KERN_INFO "Btrfs snapshot creation "
+                                      "failed, looping\n");
+                               error = -EMLINK;
+                               btrfs_free_path(path);
+                               goto out_drop_write;
+                       }
+                       btrfs_release_path(snap_src->fs_info->tree_root, path);
+                       test = test->d_parent;
+               }
+create:
+               btrfs_free_path(path);
+               error = create_snapshot(snap_src, dentry, name, namelen);
+       } else {
+               error = create_subvol(BTRFS_I(parent->dentry->d_inode)->root,
+                                     dentry, name, namelen);
+       }
+       if (error)
+               goto out_drop_write;
+
+       fsnotify_mkdir(parent->dentry->d_inode, dentry);
+out_drop_write:
+       mnt_drop_write(parent->mnt);
+out_dput:
+       dput(dentry);
+out_unlock:
+       mutex_unlock(&parent->dentry->d_inode->i_mutex);
+       return error;
+}
+
+
+static int btrfs_defrag_file(struct file *file)
 {
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -225,7 +374,7 @@ int btrfs_defrag_file(struct file *file)
        unsigned long i;
        int ret;
 
-       ret = btrfs_check_free_space(root, inode->i_size, 0);
+       ret = btrfs_check_data_free_space(root, inode, inode->i_size);
        if (ret)
                return -ENOSPC;
 
@@ -274,8 +423,7 @@ again:
                 */
                clear_page_dirty_for_io(page);
 
-               set_extent_delalloc(io_tree, page_start,
-                                   page_end, GFP_NOFS);
+               btrfs_set_extent_delalloc(inode, page_start, page_end);
 
                unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
                set_page_dirty(page);
@@ -307,15 +455,15 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
        int namelen;
        int mod = 0;
 
-       vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
 
-       if (!vol_args)
-               return -ENOMEM;
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
 
-       if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
-               ret = -EFAULT;
-               goto out;
-       }
+       vol_args = memdup_user(arg, sizeof(*vol_args));
+       if (IS_ERR(vol_args))
+               return PTR_ERR(vol_args);
 
        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        namelen = strlen(vol_args->name);
@@ -331,7 +479,7 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
                devid = simple_strtoull(devstr, &end, 10);
                printk(KERN_INFO "resizing devid %llu\n", devid);
        }
-       device = btrfs_find_device(root, devid, NULL);
+       device = btrfs_find_device(root, devid, NULL, NULL);
        if (!device) {
                printk(KERN_INFO "resizer unable to find device %llu\n", devid);
                ret = -EINVAL;
@@ -391,30 +539,28 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 
 out_unlock:
        mutex_unlock(&root->fs_info->volume_mutex);
-out:
        kfree(vol_args);
        return ret;
 }
 
-static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
-                                           void __user *arg)
+static noinline int btrfs_ioctl_snap_create(struct file *file,
+                                           void __user *arg, int subvol)
 {
+       struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
        struct btrfs_ioctl_vol_args *vol_args;
        struct btrfs_dir_item *di;
        struct btrfs_path *path;
+       struct file *src_file;
        u64 root_dirid;
        int namelen;
-       int ret;
-
-       vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+       int ret = 0;
 
-       if (!vol_args)
-               return -ENOMEM;
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
 
-       if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
-               ret = -EFAULT;
-               goto out;
-       }
+       vol_args = memdup_user(arg, sizeof(*vol_args));
+       if (IS_ERR(vol_args))
+               return PTR_ERR(vol_args);
 
        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        namelen = strlen(vol_args->name);
@@ -445,12 +591,32 @@ static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
                goto out;
        }
 
-       mutex_lock(&root->fs_info->drop_mutex);
-       if (root == root->fs_info->tree_root)
-               ret = create_subvol(root, vol_args->name, namelen);
-       else
-               ret = create_snapshot(root, vol_args->name, namelen);
-       mutex_unlock(&root->fs_info->drop_mutex);
+       if (subvol) {
+               ret = btrfs_mksubvol(&file->f_path, vol_args->name,
+                                    file->f_path.dentry->d_inode->i_mode,
+                                    namelen, NULL);
+       } else {
+               struct inode *src_inode;
+               src_file = fget(vol_args->fd);
+               if (!src_file) {
+                       ret = -EINVAL;
+                       goto out;
+               }
+
+               src_inode = src_file->f_path.dentry->d_inode;
+               if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
+                       printk(KERN_INFO "btrfs: Snapshot src from "
+                              "another FS\n");
+                       ret = -EINVAL;
+                       fput(src_file);
+                       goto out;
+               }
+               ret = btrfs_mksubvol(&file->f_path, vol_args->name,
+                            file->f_path.dentry->d_inode->i_mode,
+                            namelen, BTRFS_I(src_inode)->root);
+               fput(src_file);
+       }
+
 out:
        kfree(vol_args);
        return ret;
@@ -460,114 +626,143 @@ static int btrfs_ioctl_defrag(struct file *file)
 {
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
+       int ret;
+
+       ret = mnt_want_write(file->f_path.mnt);
+       if (ret)
+               return ret;
 
        switch (inode->i_mode & S_IFMT) {
        case S_IFDIR:
+               if (!capable(CAP_SYS_ADMIN)) {
+                       ret = -EPERM;
+                       goto out;
+               }
                btrfs_defrag_root(root, 0);
                btrfs_defrag_root(root->fs_info->extent_root, 0);
                break;
        case S_IFREG:
+               if (!(file->f_mode & FMODE_WRITE)) {
+                       ret = -EINVAL;
+                       goto out;
+               }
                btrfs_defrag_file(file);
                break;
        }
-
-       return 0;
+out:
+       mnt_drop_write(file->f_path.mnt);
+       return ret;
 }
 
-long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
+static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 {
        struct btrfs_ioctl_vol_args *vol_args;
        int ret;
 
-       vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
 
-       if (!vol_args)
-               return -ENOMEM;
+       vol_args = memdup_user(arg, sizeof(*vol_args));
+       if (IS_ERR(vol_args))
+               return PTR_ERR(vol_args);
 
-       if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
-               ret = -EFAULT;
-               goto out;
-       }
        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        ret = btrfs_init_new_device(root, vol_args->name);
 
-out:
        kfree(vol_args);
        return ret;
 }
 
-long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
+static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 {
        struct btrfs_ioctl_vol_args *vol_args;
        int ret;
 
-       vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
 
-       if (!vol_args)
-               return -ENOMEM;
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
+
+       vol_args = memdup_user(arg, sizeof(*vol_args));
+       if (IS_ERR(vol_args))
+               return PTR_ERR(vol_args);
 
-       if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
-               ret = -EFAULT;
-               goto out;
-       }
        vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        ret = btrfs_rm_device(root, vol_args->name);
 
-out:
        kfree(vol_args);
        return ret;
 }
 
-int dup_item_to_inode(struct btrfs_trans_handle *trans,
-                      struct btrfs_root *root,
-                      struct btrfs_path *path,
-                      struct extent_buffer *leaf,
-                      int slot,
-                      struct btrfs_key *key,
-                      u64 destino)
-{
-       char *dup;
-       int len = btrfs_item_size_nr(leaf, slot);
-       struct btrfs_key ckey = *key;
-       int ret = 0;
-
-       dup = kmalloc(len, GFP_NOFS);
-       if (!dup)
-               return -ENOMEM;
-
-       read_extent_buffer(leaf, dup, btrfs_item_ptr_offset(leaf, slot), len);
-       btrfs_release_path(root, path);
-
-       ckey.objectid = destino;
-       ret = btrfs_insert_item(trans, root, &ckey, dup, len);
-       kfree(dup);
-       return ret;
-}
-
-long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
+static long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
+               u64 off, u64 olen, u64 destoff)
 {
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
        struct file *src_file;
        struct inode *src;
        struct btrfs_trans_handle *trans;
-       int ret;
-       u64 pos;
        struct btrfs_path *path;
-       struct btrfs_key key;
        struct extent_buffer *leaf;
+       char *buf;
+       struct btrfs_key key;
        u32 nritems;
        int slot;
+       int ret;
+       u64 len = olen;
+       u64 bs = root->fs_info->sb->s_blocksize;
+       u64 hint_byte;
+
+       /*
+        * TODO:
+        * - split compressed inline extents.  annoying: we need to
+        *   decompress into destination's address_space (the file offset
+        *   may change, so source mapping won't do), then recompress (or
+        *   otherwise reinsert) a subrange.
+        * - allow ranges within the same file to be cloned (provided
+        *   they don't overlap)?
+        */
 
-       src_file = fget(src_fd);
-       if (!src_file)
-               return -EBADF;
+       /* the destination must be opened for writing */
+       if (!(file->f_mode & FMODE_WRITE))
+               return -EINVAL;
+
+       ret = mnt_want_write(file->f_path.mnt);
+       if (ret)
+               return ret;
+
+       src_file = fget(srcfd);
+       if (!src_file) {
+               ret = -EBADF;
+               goto out_drop_write;
+       }
        src = src_file->f_dentry->d_inode;
 
+       ret = -EINVAL;
+       if (src == inode)
+               goto out_fput;
+
+       ret = -EISDIR;
+       if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
+               goto out_fput;
+
        ret = -EXDEV;
-       if (src->i_sb != inode->i_sb)
+       if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
+               goto out_fput;
+
+       ret = -ENOMEM;
+       buf = vmalloc(btrfs_level_size(root, 0));
+       if (!buf)
                goto out_fput;
 
+       path = btrfs_alloc_path();
+       if (!path) {
+               vfree(buf);
+               goto out_fput;
+       }
+       path->reada = 2;
+
        if (inode < src) {
                mutex_lock(&inode->i_mutex);
                mutex_lock(&src->i_mutex);
@@ -576,31 +771,46 @@ long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
                mutex_lock(&inode->i_mutex);
        }
 
-       ret = -ENOTEMPTY;
-       if (inode->i_size)
+       /* determine range to clone */
+       ret = -EINVAL;
+       if (off >= src->i_size || off + len > src->i_size)
+               goto out_unlock;
+       if (len == 0)
+               olen = len = src->i_size - off;
+       /* if we extend to eof, continue to block boundary */
+       if (off + len == src->i_size)
+               len = ((src->i_size + bs-1) & ~(bs-1))
+                       - off;
+
+       /* verify the end result is block aligned */
+       if ((off & (bs-1)) ||
+           ((off + len) & (bs-1)))
                goto out_unlock;
 
        /* do any pending delalloc/csum calc on src, one way or
           another, and lock file content */
        while (1) {
-               filemap_write_and_wait(src->i_mapping);
-               lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
-               if (BTRFS_I(src)->delalloc_bytes == 0)
+               struct btrfs_ordered_extent *ordered;
+               lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
+               ordered = btrfs_lookup_first_ordered_extent(inode, off+len);
+               if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
                        break;
-               unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
+               unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
+               if (ordered)
+                       btrfs_put_ordered_extent(ordered);
+               btrfs_wait_ordered_range(src, off, off+len);
        }
 
-       trans = btrfs_start_transaction(root, 0);
-       path = btrfs_alloc_path();
-       if (!path) {
-               ret = -ENOMEM;
-               goto out;
-       }
-       key.offset = 0;
-       key.type = BTRFS_EXTENT_DATA_KEY;
+       trans = btrfs_start_transaction(root, 1);
+       BUG_ON(!trans);
+
+       /* punch hole in destination first */
+       btrfs_drop_extents(trans, root, inode, off, off+len, 0, &hint_byte);
+
+       /* clone data */
        key.objectid = src->i_ino;
-       pos = 0;
-       path->reada = 2;
+       key.type = BTRFS_EXTENT_DATA_KEY;
+       key.offset = 0;
 
        while (1) {
                /*
@@ -611,97 +821,190 @@ long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
                if (ret < 0)
                        goto out;
 
-               if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
+               nritems = btrfs_header_nritems(path->nodes[0]);
+               if (path->slots[0] >= nritems) {
                        ret = btrfs_next_leaf(root, path);
                        if (ret < 0)
                                goto out;
                        if (ret > 0)
                                break;
+                       nritems = btrfs_header_nritems(path->nodes[0]);
                }
                leaf = path->nodes[0];
                slot = path->slots[0];
-               btrfs_item_key_to_cpu(leaf, &key, slot);
-               nritems = btrfs_header_nritems(leaf);
 
-               if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
+               btrfs_item_key_to_cpu(leaf, &key, slot);
+               if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
                    key.objectid != src->i_ino)
                        break;
 
                if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
                        struct btrfs_file_extent_item *extent;
-                       int found_type;
-                       pos = key.offset;
+                       int type;
+                       u32 size;
+                       struct btrfs_key new_key;
+                       u64 disko = 0, diskl = 0;
+                       u64 datao = 0, datal = 0;
+                       u8 comp;
+
+                       size = btrfs_item_size_nr(leaf, slot);
+                       read_extent_buffer(leaf, buf,
+                                          btrfs_item_ptr_offset(leaf, slot),
+                                          size);
+
                        extent = btrfs_item_ptr(leaf, slot,
                                                struct btrfs_file_extent_item);
-                       found_type = btrfs_file_extent_type(leaf, extent);
-                       if (found_type == BTRFS_FILE_EXTENT_REG) {
-                               u64 len = btrfs_file_extent_num_bytes(leaf,
+                       comp = btrfs_file_extent_compression(leaf, extent);
+                       type = btrfs_file_extent_type(leaf, extent);
+                       if (type == BTRFS_FILE_EXTENT_REG) {
+                               disko = btrfs_file_extent_disk_bytenr(leaf,
                                                                      extent);
-                               u64 ds = btrfs_file_extent_disk_bytenr(leaf,
-                                                                      extent);
-                               u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
+                               diskl = btrfs_file_extent_disk_num_bytes(leaf,
                                                                 extent);
-                               u64 off = btrfs_file_extent_offset(leaf,
-                                                                  extent);
-                               btrfs_insert_file_extent(trans, root,
-                                                        inode->i_ino, pos,
-                                                        ds, dl, len, off);
-                               /* ds == 0 means there's a hole */
-                               if (ds != 0) {
-                                       btrfs_inc_extent_ref(trans, root,
-                                                    ds, dl,
-                                                    root->root_key.objectid,
-                                                    trans->transid,
-                                                    inode->i_ino, pos);
+                               datao = btrfs_file_extent_offset(leaf, extent);
+                               datal = btrfs_file_extent_num_bytes(leaf,
+                                                                   extent);
+                       } else if (type == BTRFS_FILE_EXTENT_INLINE) {
+                               /* take upper bound, may be compressed */
+                               datal = btrfs_file_extent_ram_bytes(leaf,
+                                                                   extent);
+                       }
+                       btrfs_release_path(root, path);
+
+                       if (key.offset + datal < off ||
+                           key.offset >= off+len)
+                               goto next;
+
+                       memcpy(&new_key, &key, sizeof(new_key));
+                       new_key.objectid = inode->i_ino;
+                       new_key.offset = key.offset + destoff - off;
+
+                       if (type == BTRFS_FILE_EXTENT_REG) {
+                               ret = btrfs_insert_empty_item(trans, root, path,
+                                                             &new_key, size);
+                               if (ret)
+                                       goto out;
+
+                               leaf = path->nodes[0];
+                               slot = path->slots[0];
+                               write_extent_buffer(leaf, buf,
+                                           btrfs_item_ptr_offset(leaf, slot),
+                                           size);
+
+                               extent = btrfs_item_ptr(leaf, slot,
+                                               struct btrfs_file_extent_item);
+
+                               if (off > key.offset) {
+                                       datao += off - key.offset;
+                                       datal -= off - key.offset;
+                               }
+                               if (key.offset + datao + datal + key.offset >
+                                   off + len)
+                                       datal = off + len - key.offset - datao;
+                               /* disko == 0 means it's a hole */
+                               if (!disko)
+                                       datao = 0;
+
+                               btrfs_set_file_extent_offset(leaf, extent,
+                                                            datao);
+                               btrfs_set_file_extent_num_bytes(leaf, extent,
+                                                               datal);
+                               if (disko) {
+                                       inode_add_bytes(inode, datal);
+                                       ret = btrfs_inc_extent_ref(trans, root,
+                                                  disko, diskl, leaf->start,
+                                                  root->root_key.objectid,
+                                                  trans->transid,
+                                                  inode->i_ino);
+                                       BUG_ON(ret);
                                }
-                               pos = key.offset + len;
-                       } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
-                               ret = dup_item_to_inode(trans, root, path,
-                                                       leaf, slot, &key,
-                                                       inode->i_ino);
+                       } else if (type == BTRFS_FILE_EXTENT_INLINE) {
+                               u64 skip = 0;
+                               u64 trim = 0;
+                               if (off > key.offset) {
+                                       skip = off - key.offset;
+                                       new_key.offset += skip;
+                               }
+
+                               if (key.offset + datal > off+len)
+                                       trim = key.offset + datal - (off+len);
+
+                               if (comp && (skip || trim)) {
+                                       ret = -EINVAL;
+                                       goto out;
+                               }
+                               size -= skip + trim;
+                               datal -= skip + trim;
+                               ret = btrfs_insert_empty_item(trans, root, path,
+                                                             &new_key, size);
                                if (ret)
                                        goto out;
-                               pos = key.offset + btrfs_item_size_nr(leaf,
-                                                                     slot);
+
+                               if (skip) {
+                                       u32 start =
+                                         btrfs_file_extent_calc_inline_size(0);
+                                       memmove(buf+start, buf+start+skip,
+                                               datal);
+                               }
+
+                               leaf = path->nodes[0];
+                               slot = path->slots[0];
+                               write_extent_buffer(leaf, buf,
+                                           btrfs_item_ptr_offset(leaf, slot),
+                                           size);
+                               inode_add_bytes(inode, datal);
                        }
-               } else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
-                       ret = dup_item_to_inode(trans, root, path, leaf,
-                                               slot, &key, inode->i_ino);
 
-                       if (ret)
-                               goto out;
+                       btrfs_mark_buffer_dirty(leaf);
                }
-               key.offset++;
+
+next:
                btrfs_release_path(root, path);
+               key.offset++;
        }
-
        ret = 0;
 out:
-       btrfs_free_path(path);
-
-       inode->i_blocks = src->i_blocks;
-       i_size_write(inode, src->i_size);
-       btrfs_update_inode(trans, root, inode);
-
-       unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
-
+       btrfs_release_path(root, path);
+       if (ret == 0) {
+               inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+               if (destoff + olen > inode->i_size)
+                       btrfs_i_size_write(inode, destoff + olen);
+               BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
+               ret = btrfs_update_inode(trans, root, inode);
+       }
        btrfs_end_transaction(trans, root);
-
+       unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
+       if (ret)
+               vmtruncate(inode, 0);
 out_unlock:
        mutex_unlock(&src->i_mutex);
        mutex_unlock(&inode->i_mutex);
+       vfree(buf);
+       btrfs_free_path(path);
 out_fput:
        fput(src_file);
+out_drop_write:
+       mnt_drop_write(file->f_path.mnt);
        return ret;
 }
 
+static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
+{
+       struct btrfs_ioctl_clone_range_args args;
+
+       if (copy_from_user(&args, argp, sizeof(args)))
+               return -EFAULT;
+       return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
+                                args.src_length, args.dest_offset);
+}
+
 /*
  * there are many ways the trans_start and trans_end ioctls can lead
  * to deadlocks.  They should only be used by applications that
  * basically own the machine, and have a very in depth understanding
  * of all the possible deadlocks and enospc problems.
  */
-long btrfs_ioctl_trans_start(struct file *file)
+static long btrfs_ioctl_trans_start(struct file *file)
 {
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -716,6 +1019,10 @@ long btrfs_ioctl_trans_start(struct file *file)
                goto out;
        }
 
+       ret = mnt_want_write(file->f_path.mnt);
+       if (ret)
+               goto out;
+
        mutex_lock(&root->fs_info->trans_mutex);
        root->fs_info->open_ioctl_trans++;
        mutex_unlock(&root->fs_info->trans_mutex);
@@ -749,12 +1056,14 @@ long btrfs_ioctl_trans_end(struct file *file)
                goto out;
        }
        btrfs_end_transaction(trans, root);
-       file->private_data = 0;
+       file->private_data = NULL;
 
        mutex_lock(&root->fs_info->trans_mutex);
        root->fs_info->open_ioctl_trans--;
        mutex_unlock(&root->fs_info->trans_mutex);
 
+       mnt_drop_write(file->f_path.mnt);
+
 out:
        return ret;
 }
@@ -763,22 +1072,27 @@ long btrfs_ioctl(struct file *file, unsigned int
                cmd, unsigned long arg)
 {
        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+       void __user *argp = (void __user *)arg;
 
        switch (cmd) {
        case BTRFS_IOC_SNAP_CREATE:
-               return btrfs_ioctl_snap_create(root, (void __user *)arg);
+               return btrfs_ioctl_snap_create(file, argp, 0);
+       case BTRFS_IOC_SUBVOL_CREATE:
+               return btrfs_ioctl_snap_create(file, argp, 1);
        case BTRFS_IOC_DEFRAG:
                return btrfs_ioctl_defrag(file);
        case BTRFS_IOC_RESIZE:
-               return btrfs_ioctl_resize(root, (void __user *)arg);
+               return btrfs_ioctl_resize(root, argp);
        case BTRFS_IOC_ADD_DEV:
-               return btrfs_ioctl_add_dev(root, (void __user *)arg);
+               return btrfs_ioctl_add_dev(root, argp);
        case BTRFS_IOC_RM_DEV:
-               return btrfs_ioctl_rm_dev(root, (void __user *)arg);
+               return btrfs_ioctl_rm_dev(root, argp);
        case BTRFS_IOC_BALANCE:
                return btrfs_balance(root->fs_info->dev_root);
        case BTRFS_IOC_CLONE:
-               return btrfs_ioctl_clone(file, arg);
+               return btrfs_ioctl_clone(file, arg, 0, 0, 0);
+       case BTRFS_IOC_CLONE_RANGE:
+               return btrfs_ioctl_clone_range(file, argp);
        case BTRFS_IOC_TRANS_START:
                return btrfs_ioctl_trans_start(file);
        case BTRFS_IOC_TRANS_END: