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Subject[PATCH 10/27] nilfs2: persistent object allocator
Date
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>
---
fs/nilfs2/alloc.c | 504 +++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nilfs2/alloc.h | 72 ++++++++
2 files changed, 576 insertions(+), 0 deletions(-)
create mode 100644 fs/nilfs2/alloc.c
create mode 100644 fs/nilfs2/alloc.h
diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
new file mode 100644
index 0000000..d69e6ae
--- /dev/null
+++ b/fs/nilfs2/alloc.c
@@ -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
index 0000000..4ace547
--- /dev/null
+++ b/fs/nilfs2/alloc.h
@@ -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 */
--
1.5.6.3


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