]> pilppa.com Git - linux-2.6-omap-h63xx.git/commitdiff
nilfs2: persistent object allocator
authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tue, 7 Apr 2009 02:01:29 +0000 (19:01 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 7 Apr 2009 15:31:13 +0000 (08:31 -0700)
This adds common functions to allocate or deallocate entries with bitmaps
on a meta data file.  This feature is used by the DAT and ifile.

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: Yoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/nilfs2/alloc.c [new file with mode: 0644]
fs/nilfs2/alloc.h [new file with mode: 0644]

diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
new file mode 100644 (file)
index 0000000..d69e6ae
--- /dev/null
@@ -0,0 +1,504 @@
+/*
+ * alloc.c - NILFS dat/inode allocator
+ *
+ * Copyright (C) 2006-2008 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
+ *
+ * Original code was written by Koji Sato <koji@osrg.net>.
+ * Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
+ *                                Amagai Yoshiji <amagai@osrg.net>.
+ */
+
+#include <linux/types.h>
+#include <linux/buffer_head.h>
+#include <linux/fs.h>
+#include <linux/bitops.h>
+#include "mdt.h"
+#include "alloc.h"
+
+
+static inline unsigned long
+nilfs_palloc_groups_per_desc_block(const struct inode *inode)
+{
+       return (1UL << inode->i_blkbits) /
+               sizeof(struct nilfs_palloc_group_desc);
+}
+
+static inline unsigned long
+nilfs_palloc_groups_count(const struct inode *inode)
+{
+       return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));
+}
+
+int nilfs_palloc_init_blockgroup(struct inode *inode, unsigned entry_size)
+{
+       struct nilfs_mdt_info *mi = NILFS_MDT(inode);
+
+       mi->mi_bgl = kmalloc(sizeof(*mi->mi_bgl), GFP_NOFS);
+       if (!mi->mi_bgl)
+               return -ENOMEM;
+
+       bgl_lock_init(mi->mi_bgl);
+
+       nilfs_mdt_set_entry_size(inode, entry_size, 0);
+
+       mi->mi_blocks_per_group =
+               DIV_ROUND_UP(nilfs_palloc_entries_per_group(inode),
+                            mi->mi_entries_per_block) + 1;
+               /* Number of blocks in a group including entry blocks and
+                  a bitmap block */
+       mi->mi_blocks_per_desc_block =
+               nilfs_palloc_groups_per_desc_block(inode) *
+               mi->mi_blocks_per_group + 1;
+               /* Number of blocks per descriptor including the
+                  descriptor block */
+       return 0;
+}
+
+static unsigned long nilfs_palloc_group(const struct inode *inode, __u64 nr,
+                                       unsigned long *offset)
+{
+       __u64 group = nr;
+
+       *offset = do_div(group, nilfs_palloc_entries_per_group(inode));
+       return group;
+}
+
+static unsigned long
+nilfs_palloc_desc_blkoff(const struct inode *inode, unsigned long group)
+{
+       unsigned long desc_block =
+               group / nilfs_palloc_groups_per_desc_block(inode);
+       return desc_block * NILFS_MDT(inode)->mi_blocks_per_desc_block;
+}
+
+static unsigned long
+nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
+{
+       unsigned long desc_offset =
+               group % nilfs_palloc_groups_per_desc_block(inode);
+       return nilfs_palloc_desc_blkoff(inode, group) + 1 +
+               desc_offset * NILFS_MDT(inode)->mi_blocks_per_group;
+}
+
+static unsigned long
+nilfs_palloc_group_desc_nfrees(struct inode *inode, unsigned long group,
+                              const struct nilfs_palloc_group_desc *desc)
+{
+       unsigned long nfree;
+
+       spin_lock(nilfs_mdt_bgl_lock(inode, group));
+       nfree = le32_to_cpu(desc->pg_nfrees);
+       spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+       return nfree;
+}
+
+static void
+nilfs_palloc_group_desc_add_entries(struct inode *inode,
+                                   unsigned long group,
+                                   struct nilfs_palloc_group_desc *desc,
+                                   u32 n)
+{
+       spin_lock(nilfs_mdt_bgl_lock(inode, group));
+       le32_add_cpu(&desc->pg_nfrees, n);
+       spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+}
+
+static unsigned long
+nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr)
+{
+       unsigned long group, group_offset;
+
+       group = nilfs_palloc_group(inode, nr, &group_offset);
+
+       return nilfs_palloc_bitmap_blkoff(inode, group) + 1 +
+               group_offset / NILFS_MDT(inode)->mi_entries_per_block;
+}
+
+static void nilfs_palloc_desc_block_init(struct inode *inode,
+                                        struct buffer_head *bh, void *kaddr)
+{
+       struct nilfs_palloc_group_desc *desc = kaddr + bh_offset(bh);
+       unsigned long n = nilfs_palloc_groups_per_desc_block(inode);
+       __le32 nfrees;
+
+       nfrees = cpu_to_le32(nilfs_palloc_entries_per_group(inode));
+       while (n-- > 0) {
+               desc->pg_nfrees = nfrees;
+               desc++;
+       }
+}
+
+static int nilfs_palloc_get_desc_block(struct inode *inode,
+                                      unsigned long group,
+                                      int create, struct buffer_head **bhp)
+{
+       return nilfs_mdt_get_block(inode,
+                                  nilfs_palloc_desc_blkoff(inode, group),
+                                  create, nilfs_palloc_desc_block_init, bhp);
+}
+
+static int nilfs_palloc_get_bitmap_block(struct inode *inode,
+                                        unsigned long group,
+                                        int create, struct buffer_head **bhp)
+{
+       return nilfs_mdt_get_block(inode,
+                                  nilfs_palloc_bitmap_blkoff(inode, group),
+                                  create, NULL, bhp);
+}
+
+int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
+                                int create, struct buffer_head **bhp)
+{
+       return nilfs_mdt_get_block(inode, nilfs_palloc_entry_blkoff(inode, nr),
+                                  create, NULL, bhp);
+}
+
+static struct nilfs_palloc_group_desc *
+nilfs_palloc_block_get_group_desc(const struct inode *inode,
+                                 unsigned long group,
+                                 const struct buffer_head *bh, void *kaddr)
+{
+       return (struct nilfs_palloc_group_desc *)(kaddr + bh_offset(bh)) +
+               group % nilfs_palloc_groups_per_desc_block(inode);
+}
+
+static unsigned char *
+nilfs_palloc_block_get_bitmap(const struct inode *inode,
+                             const struct buffer_head *bh, void *kaddr)
+{
+       return (unsigned char *)(kaddr + bh_offset(bh));
+}
+
+void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
+                                  const struct buffer_head *bh, void *kaddr)
+{
+       unsigned long entry_offset, group_offset;
+
+       nilfs_palloc_group(inode, nr, &group_offset);
+       entry_offset = group_offset % NILFS_MDT(inode)->mi_entries_per_block;
+
+       return kaddr + bh_offset(bh) +
+               entry_offset * NILFS_MDT(inode)->mi_entry_size;
+}
+
+static int nilfs_palloc_find_available_slot(struct inode *inode,
+                                           unsigned long group,
+                                           unsigned long target,
+                                           unsigned char *bitmap,
+                                           int bsize)  /* size in bits */
+{
+       int curr, pos, end, i;
+
+       if (target > 0) {
+               end = (target + BITS_PER_LONG - 1) & ~(BITS_PER_LONG - 1);
+               if (end > bsize)
+                       end = bsize;
+               pos = nilfs_find_next_zero_bit(bitmap, end, target);
+               if (pos < end &&
+                   !nilfs_set_bit_atomic(
+                           nilfs_mdt_bgl_lock(inode, group), pos, bitmap))
+                       return pos;
+       } else
+               end = 0;
+
+       for (i = 0, curr = end;
+            i < bsize;
+            i += BITS_PER_LONG, curr += BITS_PER_LONG) {
+               /* wrap around */
+               if (curr >= bsize)
+                       curr = 0;
+               while (*((unsigned long *)bitmap + curr / BITS_PER_LONG)
+                      != ~0UL) {
+                       end = curr + BITS_PER_LONG;
+                       if (end > bsize)
+                               end = bsize;
+                       pos = nilfs_find_next_zero_bit(bitmap, end, curr);
+                       if ((pos < end) &&
+                           !nilfs_set_bit_atomic(
+                                   nilfs_mdt_bgl_lock(inode, group), pos,
+                                   bitmap))
+                               return pos;
+               }
+       }
+       return -ENOSPC;
+}
+
+static unsigned long
+nilfs_palloc_rest_groups_in_desc_block(const struct inode *inode,
+                                      unsigned long curr, unsigned long max)
+{
+       return min_t(unsigned long,
+                    nilfs_palloc_groups_per_desc_block(inode) -
+                    curr % nilfs_palloc_groups_per_desc_block(inode),
+                    max - curr + 1);
+}
+
+int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
+                                    struct nilfs_palloc_req *req)
+{
+       struct buffer_head *desc_bh, *bitmap_bh;
+       struct nilfs_palloc_group_desc *desc;
+       unsigned char *bitmap;
+       void *desc_kaddr, *bitmap_kaddr;
+       unsigned long group, maxgroup, ngroups;
+       unsigned long group_offset, maxgroup_offset;
+       unsigned long n, entries_per_group, groups_per_desc_block;
+       unsigned long i, j;
+       int pos, ret;
+
+       ngroups = nilfs_palloc_groups_count(inode);
+       maxgroup = ngroups - 1;
+       group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
+       entries_per_group = nilfs_palloc_entries_per_group(inode);
+       groups_per_desc_block = nilfs_palloc_groups_per_desc_block(inode);
+
+       for (i = 0; i < ngroups; i += n) {
+               if (group >= ngroups) {
+                       /* wrap around */
+                       group = 0;
+                       maxgroup = nilfs_palloc_group(inode, req->pr_entry_nr,
+                                                     &maxgroup_offset) - 1;
+               }
+               ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
+               if (ret < 0)
+                       return ret;
+               desc_kaddr = kmap(desc_bh->b_page);
+               desc = nilfs_palloc_block_get_group_desc(
+                       inode, group, desc_bh, desc_kaddr);
+               n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
+                                                          maxgroup);
+               for (j = 0; j < n; j++, desc++, group++) {
+                       if (nilfs_palloc_group_desc_nfrees(inode, group, desc)
+                           > 0) {
+                               ret = nilfs_palloc_get_bitmap_block(
+                                       inode, group, 1, &bitmap_bh);
+                               if (ret < 0)
+                                       goto out_desc;
+                               bitmap_kaddr = kmap(bitmap_bh->b_page);
+                               bitmap = nilfs_palloc_block_get_bitmap(
+                                       inode, bitmap_bh, bitmap_kaddr);
+                               pos = nilfs_palloc_find_available_slot(
+                                       inode, group, group_offset, bitmap,
+                                       entries_per_group);
+                               if (pos >= 0) {
+                                       /* found a free entry */
+                                       nilfs_palloc_group_desc_add_entries(
+                                               inode, group, desc, -1);
+                                       req->pr_entry_nr =
+                                               entries_per_group * group + pos;
+                                       kunmap(desc_bh->b_page);
+                                       kunmap(bitmap_bh->b_page);
+
+                                       req->pr_desc_bh = desc_bh;
+                                       req->pr_bitmap_bh = bitmap_bh;
+                                       return 0;
+                               }
+                               kunmap(bitmap_bh->b_page);
+                               brelse(bitmap_bh);
+                       }
+
+                       group_offset = 0;
+               }
+
+               kunmap(desc_bh->b_page);
+               brelse(desc_bh);
+       }
+
+       /* no entries left */
+       return -ENOSPC;
+
+ out_desc:
+       kunmap(desc_bh->b_page);
+       brelse(desc_bh);
+       return ret;
+}
+
+void nilfs_palloc_commit_alloc_entry(struct inode *inode,
+                                    struct nilfs_palloc_req *req)
+{
+       nilfs_mdt_mark_buffer_dirty(req->pr_bitmap_bh);
+       nilfs_mdt_mark_buffer_dirty(req->pr_desc_bh);
+       nilfs_mdt_mark_dirty(inode);
+
+       brelse(req->pr_bitmap_bh);
+       brelse(req->pr_desc_bh);
+}
+
+void nilfs_palloc_commit_free_entry(struct inode *inode,
+                                   struct nilfs_palloc_req *req)
+{
+       struct nilfs_palloc_group_desc *desc;
+       unsigned long group, group_offset;
+       unsigned char *bitmap;
+       void *desc_kaddr, *bitmap_kaddr;
+
+       group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
+       desc_kaddr = kmap(req->pr_desc_bh->b_page);
+       desc = nilfs_palloc_block_get_group_desc(inode, group,
+                                                req->pr_desc_bh, desc_kaddr);
+       bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
+       bitmap = nilfs_palloc_block_get_bitmap(inode, req->pr_bitmap_bh,
+                                              bitmap_kaddr);
+
+       if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
+                                   group_offset, bitmap))
+               printk(KERN_WARNING "%s: entry number %llu already freed\n",
+                      __func__, (unsigned long long)req->pr_entry_nr);
+
+       nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+
+       kunmap(req->pr_bitmap_bh->b_page);
+       kunmap(req->pr_desc_bh->b_page);
+
+       nilfs_mdt_mark_buffer_dirty(req->pr_desc_bh);
+       nilfs_mdt_mark_buffer_dirty(req->pr_bitmap_bh);
+       nilfs_mdt_mark_dirty(inode);
+
+       brelse(req->pr_bitmap_bh);
+       brelse(req->pr_desc_bh);
+}
+
+void nilfs_palloc_abort_alloc_entry(struct inode *inode,
+                                   struct nilfs_palloc_req *req)
+{
+       struct nilfs_palloc_group_desc *desc;
+       void *desc_kaddr, *bitmap_kaddr;
+       unsigned char *bitmap;
+       unsigned long group, group_offset;
+
+       group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
+       desc_kaddr = kmap(req->pr_desc_bh->b_page);
+       desc = nilfs_palloc_block_get_group_desc(inode, group,
+                                                req->pr_desc_bh, desc_kaddr);
+       bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
+       bitmap = nilfs_palloc_block_get_bitmap(inode, req->pr_bitmap_bh,
+                                              bitmap_kaddr);
+       if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
+                                   group_offset, bitmap))
+               printk(KERN_WARNING "%s: entry numer %llu already freed\n",
+                      __func__, (unsigned long long)req->pr_entry_nr);
+
+       nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+
+       kunmap(req->pr_bitmap_bh->b_page);
+       kunmap(req->pr_desc_bh->b_page);
+
+       brelse(req->pr_bitmap_bh);
+       brelse(req->pr_desc_bh);
+
+       req->pr_entry_nr = 0;
+       req->pr_bitmap_bh = NULL;
+       req->pr_desc_bh = NULL;
+}
+
+int nilfs_palloc_prepare_free_entry(struct inode *inode,
+                                   struct nilfs_palloc_req *req)
+{
+       struct buffer_head *desc_bh, *bitmap_bh;
+       unsigned long group, group_offset;
+       int ret;
+
+       group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
+       ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
+       if (ret < 0)
+               return ret;
+       ret = nilfs_palloc_get_bitmap_block(inode, group, 1, &bitmap_bh);
+       if (ret < 0) {
+               brelse(desc_bh);
+               return ret;
+       }
+
+       req->pr_desc_bh = desc_bh;
+       req->pr_bitmap_bh = bitmap_bh;
+       return 0;
+}
+
+void nilfs_palloc_abort_free_entry(struct inode *inode,
+                                  struct nilfs_palloc_req *req)
+{
+       brelse(req->pr_bitmap_bh);
+       brelse(req->pr_desc_bh);
+
+       req->pr_entry_nr = 0;
+       req->pr_bitmap_bh = NULL;
+       req->pr_desc_bh = NULL;
+}
+
+static int
+nilfs_palloc_group_is_in(struct inode *inode, unsigned long group, __u64 nr)
+{
+       __u64 first, last;
+
+       first = group * nilfs_palloc_entries_per_group(inode);
+       last = first + nilfs_palloc_entries_per_group(inode) - 1;
+       return (nr >= first) && (nr <= last);
+}
+
+int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
+{
+       struct buffer_head *desc_bh, *bitmap_bh;
+       struct nilfs_palloc_group_desc *desc;
+       unsigned char *bitmap;
+       void *desc_kaddr, *bitmap_kaddr;
+       unsigned long group, group_offset;
+       int i, j, n, ret;
+
+       for (i = 0; i < nitems; i += n) {
+               group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
+               ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
+               if (ret < 0)
+                       return ret;
+               ret = nilfs_palloc_get_bitmap_block(inode, group, 0,
+                                                   &bitmap_bh);
+               if (ret < 0) {
+                       brelse(desc_bh);
+                       return ret;
+               }
+               desc_kaddr = kmap(desc_bh->b_page);
+               desc = nilfs_palloc_block_get_group_desc(
+                       inode, group, desc_bh, desc_kaddr);
+               bitmap_kaddr = kmap(bitmap_bh->b_page);
+               bitmap = nilfs_palloc_block_get_bitmap(
+                       inode, bitmap_bh, bitmap_kaddr);
+               for (j = i, n = 0;
+                    (j < nitems) && nilfs_palloc_group_is_in(inode, group,
+                                                             entry_nrs[j]);
+                    j++, n++) {
+                       nilfs_palloc_group(inode, entry_nrs[j], &group_offset);
+                       if (!nilfs_clear_bit_atomic(
+                                   nilfs_mdt_bgl_lock(inode, group),
+                                   group_offset, bitmap)) {
+                               printk(KERN_WARNING
+                                      "%s: entry number %llu already freed\n",
+                                      __func__,
+                                      (unsigned long long)entry_nrs[j]);
+                       }
+               }
+               nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
+
+               kunmap(bitmap_bh->b_page);
+               kunmap(desc_bh->b_page);
+
+               nilfs_mdt_mark_buffer_dirty(desc_bh);
+               nilfs_mdt_mark_buffer_dirty(bitmap_bh);
+               nilfs_mdt_mark_dirty(inode);
+
+               brelse(bitmap_bh);
+               brelse(desc_bh);
+       }
+       return 0;
+}
diff --git a/fs/nilfs2/alloc.h b/fs/nilfs2/alloc.h
new file mode 100644 (file)
index 0000000..4ace547
--- /dev/null
@@ -0,0 +1,72 @@
+/*
+ * alloc.h - persistent object (dat entry/disk inode) allocator/deallocator
+ *
+ * Copyright (C) 2006-2008 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
+ *
+ * Original code was written by Koji Sato <koji@osrg.net>.
+ * Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
+ *                                Amagai Yoshiji <amagai@osrg.net>.
+ */
+
+#ifndef _NILFS_ALLOC_H
+#define _NILFS_ALLOC_H
+
+#include <linux/types.h>
+#include <linux/buffer_head.h>
+#include <linux/fs.h>
+
+static inline unsigned long
+nilfs_palloc_entries_per_group(const struct inode *inode)
+{
+       return 1UL << (inode->i_blkbits + 3 /* log2(8 = CHAR_BITS) */);
+}
+
+int nilfs_palloc_init_blockgroup(struct inode *, unsigned);
+int nilfs_palloc_get_entry_block(struct inode *, __u64, int,
+                                struct buffer_head **);
+void *nilfs_palloc_block_get_entry(const struct inode *, __u64,
+                                  const struct buffer_head *, void *);
+
+/**
+ * nilfs_palloc_req - persistent alloctor request and reply
+ * @pr_entry_nr: entry number (vblocknr or inode number)
+ * @pr_desc_bh: buffer head of the buffer containing block group descriptors
+ * @pr_bitmap_bh: buffer head of the buffer containing a block group bitmap
+ * @pr_entry_bh: buffer head of the buffer containing translation entries
+ */
+struct nilfs_palloc_req {
+       __u64 pr_entry_nr;
+       struct buffer_head *pr_desc_bh;
+       struct buffer_head *pr_bitmap_bh;
+       struct buffer_head *pr_entry_bh;
+};
+
+int nilfs_palloc_prepare_alloc_entry(struct inode *,
+                                    struct nilfs_palloc_req *);
+void nilfs_palloc_commit_alloc_entry(struct inode *,
+                                    struct nilfs_palloc_req *);
+void nilfs_palloc_abort_alloc_entry(struct inode *, struct nilfs_palloc_req *);
+void nilfs_palloc_commit_free_entry(struct inode *, struct nilfs_palloc_req *);
+int nilfs_palloc_prepare_free_entry(struct inode *, struct nilfs_palloc_req *);
+void nilfs_palloc_abort_free_entry(struct inode *, struct nilfs_palloc_req *);
+int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
+
+#define nilfs_set_bit_atomic           ext2_set_bit_atomic
+#define nilfs_clear_bit_atomic         ext2_clear_bit_atomic
+#define nilfs_find_next_zero_bit       ext2_find_next_zero_bit
+
+#endif /* _NILFS_ALLOC_H */