Btrfs ioctls for:
subvolume and snapshot creation
defragmentation
Resizing
Device add/remove
Single file cloning (COW copies)
Balancing extents across drives (restriping)
Signed-off-by: Chris Mason <chris.mason@xxxxxxxxxx>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
new file mode 100644
index 0000000..c2aa33e
--- /dev/null
+++ b/fs/btrfs/ioctl.c
@@ -0,0 +1,1132 @@
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/bio.h>
+#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/init.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/security.h>
+#include <linux/version.h>
+#include <linux/xattr.h>
+#include <linux/vmalloc.h>
+#include "compat.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "ioctl.h"
+#include "print-tree.h"
+#include "volumes.h"
+#include "locking.h"
+
+
+
+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;
+ struct btrfs_root_item root_item;
+ struct btrfs_inode_item *inode_item;
+ struct extent_buffer *leaf;
+ struct btrfs_root *new_root = root;
+ struct inode *dir;
+ int ret;
+ 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);
+ if (ret)
+ goto fail_commit;
+
+ trans = btrfs_start_transaction(root, 1);
+ BUG_ON(!trans);
+
+ ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
+ 0, &objectid);
+ if (ret)
+ goto fail;
+
+ 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;
+ }
+
+ btrfs_set_header_nritems(leaf, 0);
+ btrfs_set_header_level(leaf, 0);
+ btrfs_set_header_bytenr(leaf, leaf->start);
+ btrfs_set_header_generation(leaf, trans->transid);
+ btrfs_set_header_owner(leaf, objectid);
+
+ write_extent_buffer(leaf, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(leaf),
+ BTRFS_FSID_SIZE);
+ btrfs_mark_buffer_dirty(leaf);
+
+ inode_item = &root_item.inode;
+ memset(inode_item, 0, sizeof(*inode_item));
+ inode_item->generation = cpu_to_le64(1);
+ inode_item->size = cpu_to_le64(3);
+ inode_item->nlink = cpu_to_le32(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;
+
+ btrfs_tree_unlock(leaf);
+ free_extent_buffer(leaf);
+ leaf = NULL;
+
+ btrfs_set_root_dirid(&root_item, new_dirid);
+
+ key.objectid = objectid;
+ key.offset = 1;
+ btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+ ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
+ &root_item);
+ if (ret)
+ goto fail;
+
+ /*
+ * insert the directory item
+ */
+ key.offset = (u64)-1;
+ 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, index);
+ 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_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(trans, new_root, dentry, new_dirid,
+ BTRFS_I(dir)->block_group);
+ if (ret)
+ goto fail;
+
+fail:
+ nr = trans->blocks_used;
+ err = btrfs_commit_transaction(trans, new_root);
+ if (err && !ret)
+ ret = err;
+fail_commit:
+ btrfs_btree_balance_dirty(root, nr);
+ return ret;
+}
+
+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 = 0;
+ int err;
+ unsigned long nr = 0;
+
+ if (!root->ref_cows)
+ return -EINVAL;
+
+ ret = btrfs_check_free_space(root, 1, 0);
+ if (ret)
+ goto fail_unlock;
+
+ pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
+ if (!pending_snapshot) {
+ ret = -ENOMEM;
+ goto fail_unlock;
+ }
+ pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
+ if (!pending_snapshot->name) {
+ ret = -ENOMEM;
+ kfree(pending_snapshot);
+ goto fail_unlock;
+ }
+ 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);
+ err = btrfs_commit_transaction(trans, root);
+
+fail_unlock:
+ btrfs_btree_balance_dirty(root, nr);
+ return ret;
+}
+
+/* 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->fs->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;
+ struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+ struct btrfs_ordered_extent *ordered;
+ struct page *page;
+ unsigned long last_index;
+ unsigned long ra_pages = root->fs_info->bdi.ra_pages;
+ unsigned long total_read = 0;
+ u64 page_start;
+ u64 page_end;
+ unsigned long i;
+ int ret;
+
+ ret = btrfs_check_free_space(root, inode->i_size, 0);
+ if (ret)
+ return -ENOSPC;
+
+ mutex_lock(&inode->i_mutex);
+ last_index = inode->i_size >> PAGE_CACHE_SHIFT;
+ for (i = 0; i <= last_index; i++) {
+ if (total_read % ra_pages == 0) {
+ btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
+ min(last_index, i + ra_pages - 1));
+ }
+ total_read++;
+again:
+ page = grab_cache_page(inode->i_mapping, i);
+ if (!page)
+ goto out_unlock;
+ if (!PageUptodate(page)) {
+ btrfs_readpage(NULL, page);
+ lock_page(page);
+ if (!PageUptodate(page)) {
+ unlock_page(page);
+ page_cache_release(page);
+ goto out_unlock;
+ }
+ }
+
+ wait_on_page_writeback(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);
+
+ ordered = btrfs_lookup_ordered_extent(inode, page_start);
+ if (ordered) {
+ unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+ unlock_page(page);
+ page_cache_release(page);
+ btrfs_start_ordered_extent(inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ goto again;
+ }
+ set_page_extent_mapped(page);
+
+ /*
+ * this makes sure page_mkwrite is called on the
+ * page if it is dirtied again later
+ */
+ clear_page_dirty_for_io(page);
+
+ btrfs_set_extent_delalloc(inode, page_start, page_end);
+
+ 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:
+ mutex_unlock(&inode->i_mutex);
+ return 0;
+}
+
+/*
+ * Called inside transaction, so use GFP_NOFS
+ */
+
+static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
+{
+ u64 new_size;
+ u64 old_size;
+ u64 devid = 1;
+ struct btrfs_ioctl_vol_args *vol_args;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_device *device = NULL;
+ char *sizestr;
+ char *devstr = NULL;
+ int ret = 0;
+ int namelen;
+ int mod = 0;
+
+ if (root->fs_info->sb->s_flags & MS_RDONLY)
+ return -EROFS;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+
+ if (!vol_args)
+ return -ENOMEM;
+
+ if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
+ namelen = strlen(vol_args->name);
+
+ mutex_lock(&root->fs_info->volume_mutex);
+ sizestr = vol_args->name;
+ devstr = strchr(sizestr, ':');
+ if (devstr) {
+ char *end;
+ sizestr = devstr + 1;
+ *devstr = '\0';
+ devstr = vol_args->name;
+ devid = simple_strtoull(devstr, &end, 10);
+ printk(KERN_INFO "resizing devid %llu\n", devid);
+ }
+ device = btrfs_find_device(root, devid, NULL, NULL);
+ if (!device) {
+ printk(KERN_INFO "resizer unable to find device %llu\n", devid);
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ if (!strcmp(sizestr, "max"))
+ new_size = device->bdev->bd_inode->i_size;
+ else {
+ if (sizestr[0] == '-') {
+ mod = -1;
+ sizestr++;
+ } else if (sizestr[0] == '+') {
+ mod = 1;
+ sizestr++;
+ }
+ new_size = btrfs_parse_size(sizestr);
+ if (new_size == 0) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ }
+
+ old_size = device->total_bytes;
+
+ if (mod < 0) {
+ if (new_size > old_size) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ new_size = old_size - new_size;
+ } else if (mod > 0) {
+ new_size = old_size + new_size;
+ }
+
+ if (new_size < 256 * 1024 * 1024) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ if (new_size > device->bdev->bd_inode->i_size) {
+ ret = -EFBIG;
+ goto out_unlock;
+ }
+
+ do_div(new_size, root->sectorsize);
+ new_size *= root->sectorsize;
+
+ printk(KERN_INFO "new size for %s is %llu\n",
+ device->name, (unsigned long long)new_size);
+
+ if (new_size > old_size) {
+ trans = btrfs_start_transaction(root, 1);
+ ret = btrfs_grow_device(trans, device, new_size);
+ btrfs_commit_transaction(trans, root);
+ } else {
+ ret = btrfs_shrink_device(device, new_size);
+ }
+
+out_unlock:
+ mutex_unlock(&root->fs_info->volume_mutex);
+out:
+ kfree(vol_args);
+ return ret;
+}
+
+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 = 0;
+
+ if (root->fs_info->sb->s_flags & MS_RDONLY)
+ return -EROFS;
+
+ vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+
+ if (!vol_args)
+ return -ENOMEM;
+
+ if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
+ namelen = strlen(vol_args->name);
+ if (strchr(vol_args->name, '/')) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
+ di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
+ path, root_dirid,
+ vol_args->name, namelen, 0);
+ btrfs_free_path(path);
+
+ if (di && !IS_ERR(di)) {
+ ret = -EEXIST;
+ goto out;
+ }
+
+ if (IS_ERR(di)) {
+ ret = PTR_ERR(di);
+ goto out;
+ }
+
+ 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;
+}
+
+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;
+ }
+out:
+ mnt_drop_write(file->f_path.mnt);
+ return ret;
+}
+
+static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
+{
+ struct btrfs_ioctl_vol_args *vol_args;
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+
+ if (!vol_args)
+ return -ENOMEM;
+
+ 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;
+}
+
+static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
+{
+ struct btrfs_ioctl_vol_args *vol_args;
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (root->fs_info->sb->s_flags & MS_RDONLY)
+ return -EROFS;
+
+ vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+
+ if (!vol_args)
+ return -ENOMEM;
+
+ 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;
+}
+
+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;
+ struct btrfs_path *path;
+ 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)?
+ */
+
+ /* 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 || 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);
+ } else {
+ mutex_lock(&src->i_mutex);
+ mutex_lock(&inode->i_mutex);
+ }
+
+ /* 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) {
+ 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, 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, 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;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = 0;
+
+ while (1) {
+ /*
+ * note the key will change type as we walk through the
+ * tree.
+ */
+ ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ 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);
+ 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 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);
+ 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);
+ diskl = btrfs_file_extent_disk_num_bytes(leaf,
+ extent);
+ 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);
+ }
+ } 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;
+
+ 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);
+ }
+
+ btrfs_mark_buffer_dirty(leaf);
+ }
+
+next:
+ btrfs_release_path(root, path);
+ key.offset++;
+ }
+ ret = 0;
+out:
+ 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.
+ */
+static long btrfs_ioctl_trans_start(struct file *file)
+{
+ struct inode *inode = fdentry(file)->d_inode;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_trans_handle *trans;
+ int ret = 0;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (file->private_data) {
+ ret = -EINPROGRESS;
+ 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);
+
+ trans = btrfs_start_ioctl_transaction(root, 0);
+ if (trans)
+ file->private_data = trans;
+ else
+ ret = -ENOMEM;
+ /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
+out:
+ return ret;
+}
+
+/*
+ * 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_end(struct file *file)
+{
+ struct inode *inode = fdentry(file)->d_inode;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_trans_handle *trans;
+ int ret = 0;
+
+ trans = file->private_data;
+ if (!trans) {
+ ret = -EINVAL;
+ goto out;
+ }
+ btrfs_end_transaction(trans, root);
+ 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;
+}
+
+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(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, argp);
+ case BTRFS_IOC_ADD_DEV:
+ return btrfs_ioctl_add_dev(root, argp);
+ case BTRFS_IOC_RM_DEV:
+ 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, 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:
+ return btrfs_ioctl_trans_end(file);
+ case BTRFS_IOC_SYNC:
+ btrfs_sync_fs(file->f_dentry->d_sb, 1);
+ return 0;
+ }
+
+ return -ENOTTY;
+}
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
new file mode 100644
index 0000000..78049ea
--- /dev/null
+++ b/fs/btrfs/ioctl.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __IOCTL_
+#define __IOCTL_
+#include <linux/ioctl.h>
+
+#define BTRFS_IOCTL_MAGIC 0x94
+#define BTRFS_VOL_NAME_MAX 255
+#define BTRFS_PATH_NAME_MAX 3072
+
+struct btrfs_ioctl_vol_args {
+ __s64 fd;
+ char name[BTRFS_PATH_NAME_MAX + 1];
+};
+
+#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
+ struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, \
+ struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_RESIZE _IOW(BTRFS_IOCTL_MAGIC, 3, \
+ struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \
+ struct btrfs_ioctl_vol_args)
+/* trans start and trans end are dangerous, and only for
+ * use by applications that know how to avoid the
+ * resulting deadlocks
+ */
+#define BTRFS_IOC_TRANS_START _IO(BTRFS_IOCTL_MAGIC, 6)
+#define BTRFS_IOC_TRANS_END _IO(BTRFS_IOCTL_MAGIC, 7)
+#define BTRFS_IOC_SYNC _IO(BTRFS_IOCTL_MAGIC, 8)
+
+#define BTRFS_IOC_CLONE _IOW(BTRFS_IOCTL_MAGIC, 9, int)
+#define BTRFS_IOC_ADD_DEV _IOW(BTRFS_IOCTL_MAGIC, 10, \
+ struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_RM_DEV _IOW(BTRFS_IOCTL_MAGIC, 11, \
+ struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_BALANCE _IOW(BTRFS_IOCTL_MAGIC, 12, \
+ struct btrfs_ioctl_vol_args)
+struct btrfs_ioctl_clone_range_args {
+ __s64 src_fd;
+ __u64 src_offset, src_length;
+ __u64 dest_offset;
+};
+
+#define BTRFS_IOC_CLONE_RANGE _IOW(BTRFS_IOCTL_MAGIC, 13, \
+ struct btrfs_ioctl_clone_range_args)
+
+#define BTRFS_IOC_SUBVOL_CREATE _IOW(BTRFS_IOCTL_MAGIC, 14, \
+ struct btrfs_ioctl_vol_args)
+
+#endif
--
1.6.0.2
--
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