nilfs2: ioctl operations

This adds userland interface implemented with ioctl.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 941 insertions, 0 deletions

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
new file mode 100644
index 00000000000..35ba60ea961
--- /dev/null
+++ b/fs/nilfs2/ioctl.c
@@ -0,0 +1,941 @@
+/*
+ * ioctl.c - NILFS ioctl operations.
+ *
+ * Copyright (C) 2007, 2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Written by Koji Sato <koji@osrg.net>.
+ */
+
+#include <linux/fs.h>
+#include <linux/wait.h>
+#include <linux/smp_lock.h>	/* lock_kernel(), unlock_kernel() */
+#include <linux/capability.h>	/* capable() */
+#include <linux/uaccess.h>	/* copy_from_user(), copy_to_user() */
+#include <linux/nilfs2_fs.h>
+#include "nilfs.h"
+#include "segment.h"
+#include "bmap.h"
+#include "cpfile.h"
+#include "sufile.h"
+#include "dat.h"
+
+
+#define KMALLOC_SIZE_MIN	4096	/* 4KB */
+#define KMALLOC_SIZE_MAX	131072	/* 128 KB */
+
+static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
+				 struct nilfs_argv *argv, int dir,
+				 ssize_t (*dofunc)(struct the_nilfs *,
+						   int, int,
+						   void *, size_t, size_t))
+{
+	void *buf;
+	size_t ksize, maxmembs, total, n;
+	ssize_t nr;
+	int ret, i;
+
+	if (argv->v_nmembs == 0)
+		return 0;
+
+	for (ksize = KMALLOC_SIZE_MAX; ksize >= KMALLOC_SIZE_MIN; ksize /= 2) {
+		buf = kmalloc(ksize, GFP_NOFS);
+		if (buf != NULL)
+			break;
+	}
+	if (ksize < KMALLOC_SIZE_MIN)
+		return -ENOMEM;
+	maxmembs = ksize / argv->v_size;
+
+	ret = 0;
+	total = 0;
+	for (i = 0; i < argv->v_nmembs; i += n) {
+		n = (argv->v_nmembs - i < maxmembs) ?
+			argv->v_nmembs - i : maxmembs;
+		if ((dir & _IOC_WRITE) &&
+		    copy_from_user(buf,
+			    (void __user *)argv->v_base + argv->v_size * i,
+			    argv->v_size * n)) {
+			ret = -EFAULT;
+			break;
+		}
+		nr = (*dofunc)(nilfs, argv->v_index + i, argv->v_flags, buf,
+			       argv->v_size, n);
+		if (nr < 0) {
+			ret = nr;
+			break;
+		}
+		if ((dir & _IOC_READ) &&
+		    copy_to_user(
+			    (void __user *)argv->v_base + argv->v_size * i,
+			    buf, argv->v_size * nr)) {
+			ret = -EFAULT;
+			break;
+		}
+		total += nr;
+	}
+	argv->v_nmembs = total;
+
+	kfree(buf);
+	return ret;
+}
+
+static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
+				     unsigned int cmd, void __user *argp)
+{
+	struct inode *cpfile = NILFS_SB(inode->i_sb)->s_nilfs->ns_cpfile;
+	struct nilfs_transaction_info ti;
+	struct nilfs_cpmode cpmode;
+	int ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	if (copy_from_user(&cpmode, argp, sizeof(cpmode)))
+		return -EFAULT;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_cpfile_change_cpmode(
+		cpfile, cpmode.cm_cno, cpmode.cm_mode);
+	nilfs_transaction_end(inode->i_sb, !ret);
+	return ret;
+}
+
+static int
+nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
+			      unsigned int cmd, void __user *argp)
+{
+	struct inode *cpfile = NILFS_SB(inode->i_sb)->s_nilfs->ns_cpfile;
+	struct nilfs_transaction_info ti;
+	__u64 cno;
+	int ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	if (copy_from_user(&cno, argp, sizeof(cno)))
+		return -EFAULT;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_cpfile_delete_checkpoint(cpfile, cno);
+	nilfs_transaction_end(inode->i_sb, !ret);
+	return ret;
+}
+
+static ssize_t
+nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, int index, int flags,
+			  void *buf, size_t size, size_t nmembs)
+{
+	return nilfs_cpfile_get_cpinfo(nilfs->ns_cpfile, index, flags, buf,
+				       nmembs);
+}
+
+static int nilfs_ioctl_get_cpinfo(struct inode *inode, struct file *filp,
+				  unsigned int cmd, void __user *argp)
+{
+	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct nilfs_argv argv;
+	struct nilfs_transaction_info ti;
+	int ret;
+
+	if (copy_from_user(&argv, argp, sizeof(argv)))
+		return -EFAULT;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
+				    nilfs_ioctl_do_get_cpinfo);
+	nilfs_transaction_end(inode->i_sb, 0);
+
+	if (copy_to_user(argp, &argv, sizeof(argv)))
+		ret = -EFAULT;
+	return ret;
+}
+
+static int nilfs_ioctl_get_cpstat(struct inode *inode, struct file *filp,
+				  unsigned int cmd, void __user *argp)
+{
+	struct inode *cpfile = NILFS_SB(inode->i_sb)->s_nilfs->ns_cpfile;
+	struct nilfs_cpstat cpstat;
+	struct nilfs_transaction_info ti;
+	int ret;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_cpfile_get_stat(cpfile, &cpstat);
+	nilfs_transaction_end(inode->i_sb, 0);
+	if (ret < 0)
+		return ret;
+
+	if (copy_to_user(argp, &cpstat, sizeof(cpstat)))
+		ret = -EFAULT;
+	return ret;
+}
+
+static ssize_t
+nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, int index, int flags,
+			  void *buf, size_t size, size_t nmembs)
+{
+	return nilfs_sufile_get_suinfo(nilfs->ns_sufile, index, buf, nmembs);
+}
+
+static int nilfs_ioctl_get_suinfo(struct inode *inode, struct file *filp,
+				  unsigned int cmd, void __user *argp)
+{
+	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct nilfs_argv argv;
+	struct nilfs_transaction_info ti;
+	int ret;
+
+	if (copy_from_user(&argv, argp, sizeof(argv)))
+		return -EFAULT;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
+				    nilfs_ioctl_do_get_suinfo);
+	nilfs_transaction_end(inode->i_sb, 0);
+
+	if (copy_to_user(argp, &argv, sizeof(argv)))
+		ret = -EFAULT;
+	return ret;
+}
+
+static int nilfs_ioctl_get_sustat(struct inode *inode, struct file *filp,
+				  unsigned int cmd, void __user *argp)
+{
+	struct inode *sufile = NILFS_SB(inode->i_sb)->s_nilfs->ns_sufile;
+	struct nilfs_sustat sustat;
+	struct nilfs_transaction_info ti;
+	int ret;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_sufile_get_stat(sufile, &sustat);
+	nilfs_transaction_end(inode->i_sb, 0);
+	if (ret < 0)
+		return ret;
+
+	if (copy_to_user(argp, &sustat, sizeof(sustat)))
+		ret = -EFAULT;
+	return ret;
+}
+
+static ssize_t
+nilfs_ioctl_do_get_vinfo(struct the_nilfs *nilfs, int index, int flags,
+			 void *buf, size_t size, size_t nmembs)
+{
+	return nilfs_dat_get_vinfo(nilfs_dat_inode(nilfs), buf, nmembs);
+}
+
+static int nilfs_ioctl_get_vinfo(struct inode *inode, struct file *filp,
+				 unsigned int cmd, void __user *argp)
+{
+	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct nilfs_argv argv;
+	struct nilfs_transaction_info ti;
+	int ret;
+
+	if (copy_from_user(&argv, argp, sizeof(argv)))
+		return -EFAULT;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
+				    nilfs_ioctl_do_get_vinfo);
+	nilfs_transaction_end(inode->i_sb, 0);
+
+	if (copy_to_user(argp, &argv, sizeof(argv)))
+		ret = -EFAULT;
+	return ret;
+}
+
+static ssize_t
+nilfs_ioctl_do_get_bdescs(struct the_nilfs *nilfs, int index, int flags,
+			  void *buf, size_t size, size_t nmembs)
+{
+	struct inode *dat = nilfs_dat_inode(nilfs);
+	struct nilfs_bmap *bmap = NILFS_I(dat)->i_bmap;
+	struct nilfs_bdesc *bdescs = buf;
+	int ret, i;
+
+	for (i = 0; i < nmembs; i++) {
+		ret = nilfs_bmap_lookup_at_level(bmap,
+						 bdescs[i].bd_offset,
+						 bdescs[i].bd_level + 1,
+						 &bdescs[i].bd_blocknr);
+		if (ret < 0) {
+			if (ret != -ENOENT)
+				return ret;
+			bdescs[i].bd_blocknr = 0;
+		}
+	}
+	return nmembs;
+}
+
+static int nilfs_ioctl_get_bdescs(struct inode *inode, struct file *filp,
+				  unsigned int cmd, void __user *argp)
+{
+	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct nilfs_argv argv;
+	struct nilfs_transaction_info ti;
+	int ret;
+
+	if (copy_from_user(&argv, argp, sizeof(argv)))
+		return -EFAULT;
+
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
+				    nilfs_ioctl_do_get_bdescs);
+	nilfs_transaction_end(inode->i_sb, 0);
+
+	if (copy_to_user(argp, &argv, sizeof(argv)))
+		ret = -EFAULT;
+	return ret;
+}
+
+static int nilfs_ioctl_move_inode_block(struct inode *inode,
+					struct nilfs_vdesc *vdesc,
+					struct list_head *buffers)
+{
+	struct buffer_head *bh;
+	int ret;
+
+	if (vdesc->vd_flags == 0)
+		ret = nilfs_gccache_submit_read_data(
+			inode, vdesc->vd_offset, vdesc->vd_blocknr,
+			vdesc->vd_vblocknr, &bh);
+	else
+		ret = nilfs_gccache_submit_read_node(
+			inode, vdesc->vd_blocknr, vdesc->vd_vblocknr, &bh);
+
+	if (unlikely(ret < 0)) {
+		if (ret == -ENOENT)
+			printk(KERN_CRIT
+			       "%s: invalid virtual block address (%s): "
+			       "ino=%llu, cno=%llu, offset=%llu, "
+			       "blocknr=%llu, vblocknr=%llu\n",
+			       __func__, vdesc->vd_flags ? "node" : "data",
+			       (unsigned long long)vdesc->vd_ino,
+			       (unsigned long long)vdesc->vd_cno,
+			       (unsigned long long)vdesc->vd_offset,
+			       (unsigned long long)vdesc->vd_blocknr,
+			       (unsigned long long)vdesc->vd_vblocknr);
+		return ret;
+	}
+	bh->b_private = vdesc;
+	list_add_tail(&bh->b_assoc_buffers, buffers);
+	return 0;
+}
+
+static ssize_t
+nilfs_ioctl_do_move_blocks(struct the_nilfs *nilfs, int index, int flags,
+			   void *buf, size_t size, size_t nmembs)
+{
+	struct inode *inode;
+	struct nilfs_vdesc *vdesc;
+	struct buffer_head *bh, *n;
+	LIST_HEAD(buffers);
+	ino_t ino;
+	__u64 cno;
+	int i, ret;
+
+	for (i = 0, vdesc = buf; i < nmembs; ) {
+		ino = vdesc->vd_ino;
+		cno = vdesc->vd_cno;
+		inode = nilfs_gc_iget(nilfs, ino, cno);
+		if (unlikely(inode == NULL)) {
+			ret = -ENOMEM;
+			goto failed;
+		}
+		do {
+			ret = nilfs_ioctl_move_inode_block(inode, vdesc,
+							   &buffers);
+			if (unlikely(ret < 0))
+				goto failed;
+			vdesc++;
+		} while (++i < nmembs &&
+			 vdesc->vd_ino == ino && vdesc->vd_cno == cno);
+	}
+
+	list_for_each_entry_safe(bh, n, &buffers, b_assoc_buffers) {
+		ret = nilfs_gccache_wait_and_mark_dirty(bh);
+		if (unlikely(ret < 0)) {
+			if (ret == -EEXIST) {
+				vdesc = bh->b_private;
+				printk(KERN_CRIT
+				       "%s: conflicting %s buffer: "
+				       "ino=%llu, cno=%llu, offset=%llu, "
+				       "blocknr=%llu, vblocknr=%llu\n",
+				       __func__,
+				       vdesc->vd_flags ? "node" : "data",
+				       (unsigned long long)vdesc->vd_ino,
+				       (unsigned long long)vdesc->vd_cno,
+				       (unsigned long long)vdesc->vd_offset,
+				       (unsigned long long)vdesc->vd_blocknr,
+				       (unsigned long long)vdesc->vd_vblocknr);
+			}
+			goto failed;
+		}
+		list_del_init(&bh->b_assoc_buffers);
+		bh->b_private = NULL;
+		brelse(bh);
+	}
+	return nmembs;
+
+ failed:
+	list_for_each_entry_safe(bh, n, &buffers, b_assoc_buffers) {
+		list_del_init(&bh->b_assoc_buffers);
+		bh->b_private = NULL;
+		brelse(bh);
+	}
+	return ret;
+}
+
+static inline int nilfs_ioctl_move_blocks(struct the_nilfs *nilfs,
+					  struct nilfs_argv *argv,
+					  int dir)
+{
+	return nilfs_ioctl_wrap_copy(nilfs, argv, dir,
+				     nilfs_ioctl_do_move_blocks);
+}
+
+static ssize_t
+nilfs_ioctl_do_delete_checkpoints(struct the_nilfs *nilfs, int index,
+				  int flags, void *buf, size_t size,
+				  size_t nmembs)
+{
+	struct inode *cpfile = nilfs->ns_cpfile;
+	struct nilfs_period *periods = buf;
+	int ret, i;
+
+	for (i = 0; i < nmembs; i++) {
+		ret = nilfs_cpfile_delete_checkpoints(
+			cpfile, periods[i].p_start, periods[i].p_end);
+		if (ret < 0)
+			return ret;
+	}
+	return nmembs;
+}
+
+static inline int nilfs_ioctl_delete_checkpoints(struct the_nilfs *nilfs,
+						 struct nilfs_argv *argv,
+						 int dir)
+{
+	return nilfs_ioctl_wrap_copy(nilfs, argv, dir,
+				     nilfs_ioctl_do_delete_checkpoints);
+}
+
+static ssize_t
+nilfs_ioctl_do_free_vblocknrs(struct the_nilfs *nilfs, int index, int flags,
+			      void *buf, size_t size, size_t nmembs)
+{
+	int ret = nilfs_dat_freev(nilfs_dat_inode(nilfs), buf, nmembs);
+
+	return (ret < 0) ? ret : nmembs;
+}
+
+static inline int nilfs_ioctl_free_vblocknrs(struct the_nilfs *nilfs,
+					     struct nilfs_argv *argv,
+					     int dir)
+{
+	return nilfs_ioctl_wrap_copy(nilfs, argv, dir,
+				     nilfs_ioctl_do_free_vblocknrs);
+}
+
+static ssize_t
+nilfs_ioctl_do_mark_blocks_dirty(struct the_nilfs *nilfs, int index, int flags,
+				 void *buf, size_t size, size_t nmembs)
+{
+	struct inode *dat = nilfs_dat_inode(nilfs);
+	struct nilfs_bmap *bmap = NILFS_I(dat)->i_bmap;
+	struct nilfs_bdesc *bdescs = buf;
+	int ret, i;
+
+	for (i = 0; i < nmembs; i++) {
+		/* XXX: use macro or inline func to check liveness */
+		ret = nilfs_bmap_lookup_at_level(bmap,
+						 bdescs[i].bd_offset,
+						 bdescs[i].bd_level + 1,
+						 &bdescs[i].bd_blocknr);
+		if (ret < 0) {
+			if (ret != -ENOENT)
+				return ret;
+			bdescs[i].bd_blocknr = 0;
+		}
+		if (bdescs[i].bd_blocknr != bdescs[i].bd_oblocknr)
+			/* skip dead block */
+			continue;
+		if (bdescs[i].bd_level == 0) {
+			ret = nilfs_mdt_mark_block_dirty(dat,
+							 bdescs[i].bd_offset);
+			if (ret < 0) {
+				BUG_ON(ret == -ENOENT);
+				return ret;
+			}
+		} else {
+			ret = nilfs_bmap_mark(bmap, bdescs[i].bd_offset,
+					      bdescs[i].bd_level);
+			if (ret < 0) {
+				BUG_ON(ret == -ENOENT);
+				return ret;
+			}
+		}
+	}
+	return nmembs;
+}
+
+static inline int nilfs_ioctl_mark_blocks_dirty(struct the_nilfs *nilfs,
+						struct nilfs_argv *argv,
+						int dir)
+{
+	return nilfs_ioctl_wrap_copy(nilfs, argv, dir,
+				     nilfs_ioctl_do_mark_blocks_dirty);
+}
+
+static ssize_t
+nilfs_ioctl_do_free_segments(struct the_nilfs *nilfs, int index, int flags,
+			     void *buf, size_t size, size_t nmembs)
+{
+	struct nilfs_sb_info *sbi = nilfs_get_writer(nilfs);
+	int ret;
+
+	BUG_ON(!sbi);
+	ret = nilfs_segctor_add_segments_to_be_freed(
+		NILFS_SC(sbi), buf, nmembs);
+	nilfs_put_writer(nilfs);
+
+	return (ret < 0) ? ret : nmembs;
+}
+
+static inline int nilfs_ioctl_free_segments(struct the_nilfs *nilfs,
+					     struct nilfs_argv *argv,
+					     int dir)
+{
+	return nilfs_ioctl_wrap_copy(nilfs, argv, dir,
+				     nilfs_ioctl_do_free_segments);
+}
+
+int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,
+				       void __user *argp)
+{
+	struct nilfs_argv argv[5];
+	int dir, ret;
+
+	if (copy_from_user(argv, argp, sizeof(argv)))
+		return -EFAULT;
+
+	dir = _IOC_WRITE;
+	ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], dir);
+	if (ret < 0)
+		goto out_move_blks;
+	ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], dir);
+	if (ret < 0)
+		goto out_del_cps;
+	ret = nilfs_ioctl_free_vblocknrs(nilfs, &argv[2], dir);
+	if (ret < 0)
+		goto out_free_vbns;
+	ret = nilfs_ioctl_mark_blocks_dirty(nilfs, &argv[3], dir);
+	if (ret < 0)
+		goto out_free_vbns;
+	ret = nilfs_ioctl_free_segments(nilfs, &argv[4], dir);
+	if (ret < 0)
+		goto out_free_segs;
+
+	return 0;
+
+ out_free_segs:
+	BUG(); /* XXX: not implemented yet */
+ out_free_vbns:
+	BUG();/* XXX: not implemented yet */
+ out_del_cps:
+	BUG();/* XXX: not implemented yet */
+ out_move_blks:
+	nilfs_remove_all_gcinode(nilfs);
+	return ret;
+}
+
+static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
+				      unsigned int cmd, void __user *argp)
+{
+	int ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	ret = nilfs_clean_segments(inode->i_sb, argp);
+	clear_nilfs_cond_nongc_write(NILFS_SB(inode->i_sb)->s_nilfs);
+	return ret;
+}
+
+static int nilfs_ioctl_test_cond(struct the_nilfs *nilfs, int cond)
+{
+	return (cond & NILFS_TIMEDWAIT_SEG_WRITE) &&
+		nilfs_cond_nongc_write(nilfs);
+}
+
+static void nilfs_ioctl_clear_cond(struct the_nilfs *nilfs, int cond)
+{
+	if (cond & NILFS_TIMEDWAIT_SEG_WRITE)
+		clear_nilfs_cond_nongc_write(nilfs);
+}
+
+static int nilfs_ioctl_timedwait(struct inode *inode, struct file *filp,
+				 unsigned int cmd, void __user *argp)
+{
+	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct nilfs_wait_cond wc;
+	long ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	if (copy_from_user(&wc, argp, sizeof(wc)))
+		return -EFAULT;
+
+	unlock_kernel();
+	ret = wc.wc_flags ?
+		wait_event_interruptible_timeout(
+			nilfs->ns_cleanerd_wq,
+			nilfs_ioctl_test_cond(nilfs, wc.wc_cond),
+			timespec_to_jiffies(&wc.wc_timeout)) :
+		wait_event_interruptible(
+			nilfs->ns_cleanerd_wq,
+			nilfs_ioctl_test_cond(nilfs, wc.wc_cond));
+	lock_kernel();
+	nilfs_ioctl_clear_cond(nilfs, wc.wc_cond);
+
+	if (ret > 0) {
+		jiffies_to_timespec(ret, &wc.wc_timeout);
+		if (copy_to_user(argp, &wc, sizeof(wc)))
+			return -EFAULT;
+		return 0;
+	}
+	if (ret != 0)
+		return -EINTR;
+
+	return wc.wc_flags ? -ETIME : 0;
+}
+
+static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
+			    unsigned int cmd, void __user *argp)
+{
+	__u64 cno;
+	int ret;
+
+	ret = nilfs_construct_segment(inode->i_sb);
+	if (ret < 0)
+		return ret;
+
+	if (argp != NULL) {
+		cno = NILFS_SB(inode->i_sb)->s_nilfs->ns_cno - 1;
+		if (copy_to_user(argp, &cno, sizeof(cno)))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+int nilfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
+		unsigned long arg)
+{
+	void __user *argp = (void * __user *)arg;
+
+	switch (cmd) {
+	case NILFS_IOCTL_CHANGE_CPMODE:
+		return nilfs_ioctl_change_cpmode(inode, filp, cmd, argp);
+	case NILFS_IOCTL_DELETE_CHECKPOINT:
+		return nilfs_ioctl_delete_checkpoint(inode, filp, cmd, argp);
+	case NILFS_IOCTL_GET_CPINFO:
+		return nilfs_ioctl_get_cpinfo(inode, filp, cmd, argp);
+	case NILFS_IOCTL_GET_CPSTAT:
+		return nilfs_ioctl_get_cpstat(inode, filp, cmd, argp);
+	case NILFS_IOCTL_GET_SUINFO:
+		return nilfs_ioctl_get_suinfo(inode, filp, cmd, argp);
+	case NILFS_IOCTL_GET_SUSTAT:
+		return nilfs_ioctl_get_sustat(inode, filp, cmd, argp);
+	case NILFS_IOCTL_GET_VINFO:
+		/* XXX: rename to ??? */
+		return nilfs_ioctl_get_vinfo(inode, filp, cmd, argp);
+	case NILFS_IOCTL_GET_BDESCS:
+		return nilfs_ioctl_get_bdescs(inode, filp, cmd, argp);
+	case NILFS_IOCTL_CLEAN_SEGMENTS:
+		return nilfs_ioctl_clean_segments(inode, filp, cmd, argp);
+	case NILFS_IOCTL_TIMEDWAIT:
+		return nilfs_ioctl_timedwait(inode, filp, cmd, argp);
+	case NILFS_IOCTL_SYNC:
+		return nilfs_ioctl_sync(inode, filp, cmd, argp);
+	default:
+		return -ENOTTY;
+	}
+}
+
+/* compat_ioctl */
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+
+static int nilfs_compat_locked_ioctl(struct inode *inode, struct file *filp,
+				     unsigned int cmd, unsigned long arg)
+{
+	int ret;
+
+	lock_kernel();
+	ret = nilfs_ioctl(inode, filp, cmd, arg);
+	unlock_kernel();
+	return ret;
+}
+
+static int
+nilfs_compat_ioctl_uargv32_to_uargv(struct nilfs_argv32 __user *uargv32,
+				    struct nilfs_argv __user *uargv)
+{
+	compat_uptr_t base;
+	compat_size_t nmembs, size;
+	compat_int_t index, flags;
+
+	if (get_user(base, &uargv32->v_base) ||
+	    put_user(compat_ptr(base), &uargv->v_base) ||
+	    get_user(nmembs, &uargv32->v_nmembs) ||
+	    put_user(nmembs, &uargv->v_nmembs) ||
+	    get_user(size, &uargv32->v_size) ||
+	    put_user(size, &uargv->v_size) ||
+	    get_user(index, &uargv32->v_index) ||
+	    put_user(index, &uargv->v_index) ||
+	    get_user(flags, &uargv32->v_flags) ||
+	    put_user(flags, &uargv->v_flags))
+		return -EFAULT;
+	return 0;
+}
+
+static int
+nilfs_compat_ioctl_uargv_to_uargv32(struct nilfs_argv __user *uargv,
+				    struct nilfs_argv32 __user *uargv32)
+{
+	size_t nmembs;
+
+	if (get_user(nmembs, &uargv->v_nmembs) ||
+	    put_user(nmembs, &uargv32->v_nmembs))
+		return -EFAULT;
+	return 0;
+}
+
+static int
+nilfs_compat_ioctl_get_by_argv(struct inode *inode, struct file *filp,
+			       unsigned int cmd, unsigned long arg)
+{
+	struct nilfs_argv __user *uargv;
+	struct nilfs_argv32 __user *uargv32;
+	int ret;
+
+	uargv = compat_alloc_user_space(sizeof(struct nilfs_argv));
+	uargv32 = compat_ptr(arg);
+	ret = nilfs_compat_ioctl_uargv32_to_uargv(uargv32, uargv);
+	if (ret < 0)
+		return ret;
+
+	ret = nilfs_compat_locked_ioctl(inode, filp, cmd, (unsigned long)uargv);
+	if (ret < 0)
+		return ret;
+
+	return nilfs_compat_ioctl_uargv_to_uargv32(uargv, uargv32);
+}
+
+static int
+nilfs_compat_ioctl_change_cpmode(struct inode *inode, struct file *filp,
+				 unsigned int cmd, unsigned long arg)
+{
+	struct nilfs_cpmode __user *ucpmode;
+	struct nilfs_cpmode32 __user *ucpmode32;
+	int mode;
+
+	ucpmode = compat_alloc_user_space(sizeof(struct nilfs_cpmode));
+	ucpmode32 = compat_ptr(arg);
+	if (copy_in_user(&ucpmode->cm_cno, &ucpmode32->cm_cno,
+			 sizeof(__u64)) ||
+	    get_user(mode, &ucpmode32->cm_mode) ||
+	    put_user(mode, &ucpmode->cm_mode))
+		return -EFAULT;
+
+	return nilfs_compat_locked_ioctl(
+		inode, filp, cmd, (unsigned long)ucpmode);
+}
+
+
+static inline int
+nilfs_compat_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
+				     unsigned int cmd, unsigned long arg)
+{
+	return nilfs_compat_locked_ioctl(inode, filp, cmd, arg);
+}
+
+static inline int
+nilfs_compat_ioctl_get_cpinfo(struct inode *inode, struct file *filp,
+			      unsigned int cmd, unsigned long arg)
+{
+	return nilfs_compat_ioctl_get_by_argv(inode, filp, cmd, arg);
+}
+
+static inline int
+nilfs_compat_ioctl_get_cpstat(struct inode *inode, struct file *filp,
+			      unsigned int cmd, unsigned long arg)
+{
+	return nilfs_compat_locked_ioctl(inode, filp, cmd, arg);
+}
+
+static inline int
+nilfs_compat_ioctl_get_suinfo(struct inode *inode, struct file *filp,
+			      unsigned int cmd, unsigned long arg)
+{
+	return nilfs_compat_ioctl_get_by_argv(inode, filp, cmd, arg);
+}
+
+static int
+nilfs_compat_ioctl_get_sustat(struct inode *inode, struct file *filp,
+			      unsigned int cmd, unsigned long arg)
+{
+	struct nilfs_sustat __user *usustat;
+	struct nilfs_sustat32 __user *usustat32;
+	time_t ctime, nongc_ctime;
+	int ret;
+
+	usustat = compat_alloc_user_space(sizeof(struct nilfs_sustat));
+	ret = nilfs_compat_locked_ioctl(inode, filp, cmd,
+					(unsigned long)usustat);
+	if (ret < 0)
+		return ret;
+
+	usustat32 = compat_ptr(arg);
+	if (copy_in_user(&usustat32->ss_nsegs, &usustat->ss_nsegs,
+			 sizeof(__u64)) ||
+	    copy_in_user(&usustat32->ss_ncleansegs, &usustat->ss_ncleansegs,
+			 sizeof(__u64)) ||
+	    copy_in_user(&usustat32->ss_ndirtysegs, &usustat->ss_ndirtysegs,
+			 sizeof(__u64)) ||
+	    get_user(ctime, &usustat->ss_ctime) ||
+	    put_user(ctime, &usustat32->ss_ctime) ||
+	    get_user(nongc_ctime, &usustat->ss_nongc_ctime) ||
+	    put_user(nongc_ctime, &usustat32->ss_nongc_ctime))
+		return -EFAULT;
+	return 0;
+}
+
+static inline int
+nilfs_compat_ioctl_get_vinfo(struct inode *inode, struct file *filp,
+			      unsigned int cmd, unsigned long arg)
+{
+	return nilfs_compat_ioctl_get_by_argv(inode, filp, cmd, arg);
+}
+
+static inline int
+nilfs_compat_ioctl_get_bdescs(struct inode *inode, struct file *filp,
+			     unsigned int cmd, unsigned long arg)
+{
+	return nilfs_compat_ioctl_get_by_argv(inode, filp, cmd, arg);
+}
+
+static int
+nilfs_compat_ioctl_clean_segments(struct inode *inode, struct file *filp,
+				  unsigned int cmd, unsigned long arg)
+{
+	struct nilfs_argv __user *uargv;
+	struct nilfs_argv32 __user *uargv32;
+	int i, ret;
+
+	uargv = compat_alloc_user_space(sizeof(struct nilfs_argv) * 5);
+	uargv32 = compat_ptr(arg);
+	for (i = 0; i < 5; i++) {
+		ret = nilfs_compat_ioctl_uargv32_to_uargv(&uargv32[i],
+							  &uargv[i]);
+		if (ret < 0)
+			return ret;
+	}
+	return nilfs_compat_locked_ioctl(
+		inode, filp, cmd, (unsigned long)uargv);
+}
+
+static int
+nilfs_compat_ioctl_timedwait(struct inode *inode, struct file *filp,
+			     unsigned int cmd, unsigned long arg)
+{
+	struct nilfs_wait_cond __user *uwcond;
+	struct nilfs_wait_cond32 __user *uwcond32;
+	struct timespec ts;
+	int cond, flags, ret;
+
+	uwcond = compat_alloc_user_space(sizeof(struct nilfs_wait_cond));
+	uwcond32 = compat_ptr(arg);
+	if (get_user(cond, &uwcond32->wc_cond) ||
+	    put_user(cond, &uwcond->wc_cond) ||
+	    get_user(flags, &uwcond32->wc_flags) ||
+	    put_user(flags, &uwcond->wc_flags) ||
+	    get_user(ts.tv_sec, &uwcond32->wc_timeout.tv_sec) ||
+	    get_user(ts.tv_nsec, &uwcond32->wc_timeout.tv_nsec) ||
+	    put_user(ts.tv_sec, &uwcond->wc_timeout.tv_sec) ||
+	    put_user(ts.tv_nsec, &uwcond->wc_timeout.tv_nsec))
+		return -EFAULT;
+
+	ret = nilfs_compat_locked_ioctl(inode, filp, cmd,
+					(unsigned long)uwcond);
+	if (ret < 0)
+		return ret;
+
+	if (get_user(ts.tv_sec, &uwcond->wc_timeout.tv_sec) ||
+	    get_user(ts.tv_nsec, &uwcond->wc_timeout.tv_nsec) ||
+	    put_user(ts.tv_sec, &uwcond32->wc_timeout.tv_sec) ||
+	    put_user(ts.tv_nsec, &uwcond32->wc_timeout.tv_nsec))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int nilfs_compat_ioctl_sync(struct inode *inode, struct file *filp,
+				   unsigned int cmd, unsigned long arg)
+{
+	return nilfs_compat_locked_ioctl(inode, filp, cmd, arg);
+}
+
+long nilfs_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+
+	switch (cmd) {
+	case NILFS_IOCTL32_CHANGE_CPMODE:
+		return nilfs_compat_ioctl_change_cpmode(
+			inode, filp, NILFS_IOCTL_CHANGE_CPMODE, arg);
+	case NILFS_IOCTL_DELETE_CHECKPOINT:
+		return nilfs_compat_ioctl_delete_checkpoint(
+			inode, filp, cmd, arg);
+	case NILFS_IOCTL32_GET_CPINFO:
+		return nilfs_compat_ioctl_get_cpinfo(
+			inode, filp, NILFS_IOCTL_GET_CPINFO, arg);
+	case NILFS_IOCTL_GET_CPSTAT:
+		return nilfs_compat_ioctl_get_cpstat(inode, filp, cmd, arg);
+	case NILFS_IOCTL32_GET_SUINFO:
+		return nilfs_compat_ioctl_get_suinfo(
+			inode, filp, NILFS_IOCTL_GET_SUINFO, arg);
+	case NILFS_IOCTL32_GET_SUSTAT:
+		return nilfs_compat_ioctl_get_sustat(
+			inode, filp, NILFS_IOCTL_GET_SUSTAT, arg);
+	case NILFS_IOCTL32_GET_VINFO:
+		return nilfs_compat_ioctl_get_vinfo(
+			inode, filp, NILFS_IOCTL_GET_VINFO, arg);
+	case NILFS_IOCTL32_GET_BDESCS:
+		return nilfs_compat_ioctl_get_bdescs(
+			inode, filp, NILFS_IOCTL_GET_BDESCS, arg);
+	case NILFS_IOCTL32_CLEAN_SEGMENTS:
+		return nilfs_compat_ioctl_clean_segments(
+			inode, filp, NILFS_IOCTL_CLEAN_SEGMENTS, arg);
+	case NILFS_IOCTL32_TIMEDWAIT:
+		return nilfs_compat_ioctl_timedwait(
+			inode, filp, NILFS_IOCTL_TIMEDWAIT, arg);
+	case NILFS_IOCTL_SYNC:
+		return nilfs_compat_ioctl_sync(inode, filp, cmd, arg);
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+#endif