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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /fs/nilfs2/alloc.c
Initial import
Diffstat (limited to 'fs/nilfs2/alloc.c')
-rw-r--r--fs/nilfs2/alloc.c785
1 files changed, 785 insertions, 0 deletions
diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
new file mode 100644
index 000000000..8df0f3b78
--- /dev/null
+++ b/fs/nilfs2/alloc.c
@@ -0,0 +1,785 @@
+/*
+ * 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 <linux/slab.h>
+#include "mdt.h"
+#include "alloc.h"
+
+
+/**
+ * nilfs_palloc_groups_per_desc_block - get the number of groups that a group
+ * descriptor block can maintain
+ * @inode: inode of metadata file using this allocator
+ */
+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);
+}
+
+/**
+ * nilfs_palloc_groups_count - get maximum number of groups
+ * @inode: inode of metadata file using this allocator
+ */
+static inline unsigned long
+nilfs_palloc_groups_count(const struct inode *inode)
+{
+ return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));
+}
+
+/**
+ * nilfs_palloc_init_blockgroup - initialize private variables for allocator
+ * @inode: inode of metadata file using this allocator
+ * @entry_size: size of the persistent object
+ */
+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;
+}
+
+/**
+ * nilfs_palloc_group - get group number and offset from an entry number
+ * @inode: inode of metadata file using this allocator
+ * @nr: serial number of the entry (e.g. inode number)
+ * @offset: pointer to store offset number in the group
+ */
+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;
+}
+
+/**
+ * nilfs_palloc_desc_blkoff - get block offset of a group descriptor block
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ *
+ * nilfs_palloc_desc_blkoff() returns block offset of the descriptor
+ * block which contains a descriptor of the specified 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;
+}
+
+/**
+ * nilfs_palloc_bitmap_blkoff - get block offset of a bitmap block
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ *
+ * nilfs_palloc_bitmap_blkoff() returns block offset of the bitmap
+ * block used to allocate/deallocate entries in the specified group.
+ */
+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;
+}
+
+/**
+ * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ * @desc: pointer to descriptor structure for the 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;
+}
+
+/**
+ * nilfs_palloc_group_desc_add_entries - adjust count of free entries
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ * @desc: pointer to descriptor structure for the group
+ * @n: delta to be added
+ */
+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));
+}
+
+/**
+ * nilfs_palloc_entry_blkoff - get block offset of an entry block
+ * @inode: inode of metadata file using this allocator
+ * @nr: serial number of the entry (e.g. inode number)
+ */
+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;
+}
+
+/**
+ * nilfs_palloc_desc_block_init - initialize buffer of a group descriptor block
+ * @inode: inode of metadata file
+ * @bh: buffer head of the buffer to be initialized
+ * @kaddr: kernel address mapped for the page including the buffer
+ */
+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_block(struct inode *inode, unsigned long blkoff,
+ int create,
+ void (*init_block)(struct inode *,
+ struct buffer_head *,
+ void *),
+ struct buffer_head **bhp,
+ struct nilfs_bh_assoc *prev,
+ spinlock_t *lock)
+{
+ int ret;
+
+ spin_lock(lock);
+ if (prev->bh && blkoff == prev->blkoff) {
+ get_bh(prev->bh);
+ *bhp = prev->bh;
+ spin_unlock(lock);
+ return 0;
+ }
+ spin_unlock(lock);
+
+ ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);
+ if (!ret) {
+ spin_lock(lock);
+ /*
+ * The following code must be safe for change of the
+ * cache contents during the get block call.
+ */
+ brelse(prev->bh);
+ get_bh(*bhp);
+ prev->bh = *bhp;
+ prev->blkoff = blkoff;
+ spin_unlock(lock);
+ }
+ return ret;
+}
+
+/**
+ * nilfs_palloc_get_desc_block - get buffer head of a group descriptor block
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ * @create: create flag
+ * @bhp: pointer to store the resultant buffer head
+ */
+static int nilfs_palloc_get_desc_block(struct inode *inode,
+ unsigned long group,
+ int create, struct buffer_head **bhp)
+{
+ struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+ return nilfs_palloc_get_block(inode,
+ nilfs_palloc_desc_blkoff(inode, group),
+ create, nilfs_palloc_desc_block_init,
+ bhp, &cache->prev_desc, &cache->lock);
+}
+
+/**
+ * nilfs_palloc_get_bitmap_block - get buffer head of a bitmap block
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ * @create: create flag
+ * @bhp: pointer to store the resultant buffer head
+ */
+static int nilfs_palloc_get_bitmap_block(struct inode *inode,
+ unsigned long group,
+ int create, struct buffer_head **bhp)
+{
+ struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+ return nilfs_palloc_get_block(inode,
+ nilfs_palloc_bitmap_blkoff(inode, group),
+ create, NULL, bhp,
+ &cache->prev_bitmap, &cache->lock);
+}
+
+/**
+ * nilfs_palloc_get_entry_block - get buffer head of an entry block
+ * @inode: inode of metadata file using this allocator
+ * @nr: serial number of the entry (e.g. inode number)
+ * @create: create flag
+ * @bhp: pointer to store the resultant buffer head
+ */
+int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
+ int create, struct buffer_head **bhp)
+{
+ struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+ return nilfs_palloc_get_block(inode,
+ nilfs_palloc_entry_blkoff(inode, nr),
+ create, NULL, bhp,
+ &cache->prev_entry, &cache->lock);
+}
+
+/**
+ * nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ * @bh: buffer head of the buffer storing the group descriptor block
+ * @kaddr: kernel address mapped for the page including the buffer
+ */
+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);
+}
+
+/**
+ * nilfs_palloc_block_get_entry - get kernel address of an entry
+ * @inode: inode of metadata file using this allocator
+ * @nr: serial number of the entry (e.g. inode number)
+ * @bh: buffer head of the buffer storing the entry block
+ * @kaddr: kernel address mapped for the page including the buffer
+ */
+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;
+}
+
+/**
+ * nilfs_palloc_find_available_slot - find available slot in a group
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ * @target: offset number of an entry in the group (start point)
+ * @bitmap: bitmap of the group
+ * @bsize: size in bits
+ */
+static int nilfs_palloc_find_available_slot(struct inode *inode,
+ unsigned long group,
+ unsigned long target,
+ unsigned char *bitmap,
+ int bsize)
+{
+ 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;
+}
+
+/**
+ * nilfs_palloc_rest_groups_in_desc_block - get the remaining number of groups
+ * in a group descriptor block
+ * @inode: inode of metadata file using this allocator
+ * @curr: current group number
+ * @max: maximum number of groups
+ */
+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);
+}
+
+/**
+ * nilfs_palloc_count_desc_blocks - count descriptor blocks number
+ * @inode: inode of metadata file using this allocator
+ * @desc_blocks: descriptor blocks number [out]
+ */
+static int nilfs_palloc_count_desc_blocks(struct inode *inode,
+ unsigned long *desc_blocks)
+{
+ __u64 blknum;
+ int ret;
+
+ ret = nilfs_bmap_last_key(NILFS_I(inode)->i_bmap, &blknum);
+ if (likely(!ret))
+ *desc_blocks = DIV_ROUND_UP(
+ (unsigned long)blknum,
+ NILFS_MDT(inode)->mi_blocks_per_desc_block);
+ return ret;
+}
+
+/**
+ * nilfs_palloc_mdt_file_can_grow - check potential opportunity for
+ * MDT file growing
+ * @inode: inode of metadata file using this allocator
+ * @desc_blocks: known current descriptor blocks count
+ */
+static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,
+ unsigned long desc_blocks)
+{
+ return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <
+ nilfs_palloc_groups_count(inode);
+}
+
+/**
+ * nilfs_palloc_count_max_entries - count max number of entries that can be
+ * described by descriptor blocks count
+ * @inode: inode of metadata file using this allocator
+ * @nused: current number of used entries
+ * @nmaxp: max number of entries [out]
+ */
+int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
+{
+ unsigned long desc_blocks = 0;
+ u64 entries_per_desc_block, nmax;
+ int err;
+
+ err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);
+ if (unlikely(err))
+ return err;
+
+ entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *
+ nilfs_palloc_groups_per_desc_block(inode);
+ nmax = entries_per_desc_block * desc_blocks;
+
+ if (nused == nmax &&
+ nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))
+ nmax += entries_per_desc_block;
+
+ if (nused > nmax)
+ return -ERANGE;
+
+ *nmaxp = nmax;
+ return 0;
+}
+
+/**
+ * nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
+ * @inode: inode of metadata file using this allocator
+ * @req: nilfs_palloc_req structure exchanged for the allocation
+ */
+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 = bitmap_kaddr + bh_offset(bitmap_bh);
+ 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;
+}
+
+/**
+ * nilfs_palloc_commit_alloc_entry - finish allocation of a persistent object
+ * @inode: inode of metadata file using this allocator
+ * @req: nilfs_palloc_req structure exchanged for the allocation
+ */
+void nilfs_palloc_commit_alloc_entry(struct inode *inode,
+ struct nilfs_palloc_req *req)
+{
+ mark_buffer_dirty(req->pr_bitmap_bh);
+ mark_buffer_dirty(req->pr_desc_bh);
+ nilfs_mdt_mark_dirty(inode);
+
+ brelse(req->pr_bitmap_bh);
+ brelse(req->pr_desc_bh);
+}
+
+/**
+ * nilfs_palloc_commit_free_entry - finish deallocating a persistent object
+ * @inode: inode of metadata file using this allocator
+ * @req: nilfs_palloc_req structure exchanged for the removal
+ */
+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 = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
+
+ 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);
+ else
+ nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+
+ kunmap(req->pr_bitmap_bh->b_page);
+ kunmap(req->pr_desc_bh->b_page);
+
+ mark_buffer_dirty(req->pr_desc_bh);
+ mark_buffer_dirty(req->pr_bitmap_bh);
+ nilfs_mdt_mark_dirty(inode);
+
+ brelse(req->pr_bitmap_bh);
+ brelse(req->pr_desc_bh);
+}
+
+/**
+ * nilfs_palloc_abort_alloc_entry - cancel allocation of a persistent object
+ * @inode: inode of metadata file using this allocator
+ * @req: nilfs_palloc_req structure exchanged for the allocation
+ */
+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 = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
+ 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);
+ else
+ 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;
+}
+
+/**
+ * nilfs_palloc_prepare_free_entry - prepare to deallocate a persistent object
+ * @inode: inode of metadata file using this allocator
+ * @req: nilfs_palloc_req structure exchanged for the removal
+ */
+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;
+}
+
+/**
+ * nilfs_palloc_abort_free_entry - cancel deallocating a persistent object
+ * @inode: inode of metadata file using this allocator
+ * @req: nilfs_palloc_req structure exchanged for the removal
+ */
+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;
+}
+
+/**
+ * nilfs_palloc_group_is_in - judge if an entry is in a group
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ * @nr: serial number of the entry (e.g. inode number)
+ */
+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);
+}
+
+/**
+ * nilfs_palloc_freev - deallocate a set of persistent objects
+ * @inode: inode of metadata file using this allocator
+ * @entry_nrs: array of entry numbers to be deallocated
+ * @nitems: number of entries stored in @entry_nrs
+ */
+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 = j) {
+ 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 = bitmap_kaddr + bh_offset(bitmap_bh);
+ for (j = i, n = 0;
+ (j < nitems) && nilfs_palloc_group_is_in(inode, group,
+ entry_nrs[j]);
+ j++) {
+ 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]);
+ } else {
+ n++;
+ }
+ }
+ nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
+
+ kunmap(bitmap_bh->b_page);
+ kunmap(desc_bh->b_page);
+
+ mark_buffer_dirty(desc_bh);
+ mark_buffer_dirty(bitmap_bh);
+ nilfs_mdt_mark_dirty(inode);
+
+ brelse(bitmap_bh);
+ brelse(desc_bh);
+ }
+ return 0;
+}
+
+void nilfs_palloc_setup_cache(struct inode *inode,
+ struct nilfs_palloc_cache *cache)
+{
+ NILFS_MDT(inode)->mi_palloc_cache = cache;
+ spin_lock_init(&cache->lock);
+}
+
+void nilfs_palloc_clear_cache(struct inode *inode)
+{
+ struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+ spin_lock(&cache->lock);
+ brelse(cache->prev_desc.bh);
+ brelse(cache->prev_bitmap.bh);
+ brelse(cache->prev_entry.bh);
+ cache->prev_desc.bh = NULL;
+ cache->prev_bitmap.bh = NULL;
+ cache->prev_entry.bh = NULL;
+ spin_unlock(&cache->lock);
+}
+
+void nilfs_palloc_destroy_cache(struct inode *inode)
+{
+ nilfs_palloc_clear_cache(inode);
+ NILFS_MDT(inode)->mi_palloc_cache = NULL;
+}