[PATCH 09/27] nilfs2: meta data file
From: Ryusuke Konishi
Date: Sun Sep 14 2008 - 15:16:37 EST
This adds the meta data file, which serves common buffer
functions to the DAT, sufile, cpfile, ifile, and so forth.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
---
fs/nilfs2/mdt.c | 562 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nilfs2/mdt.h | 125 ++++++++++++
2 files changed, 687 insertions(+), 0 deletions(-)
create mode 100644 fs/nilfs2/mdt.c
create mode 100644 fs/nilfs2/mdt.h
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
new file mode 100644
index 0000000..6ab8475
--- /dev/null
+++ b/fs/nilfs2/mdt.c
@@ -0,0 +1,562 @@
+/*
+ * mdt.c - meta data file for NILFS
+ *
+ * Copyright (C) 2005-2008 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 Ryusuke Konishi <ryusuke@xxxxxxxx>
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/mm.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/swap.h>
+#include "nilfs.h"
+#include "segment.h"
+#include "page.h"
+#include "mdt.h"
+
+
+#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
+
+#define INIT_UNUSED_INODE_FIELDS
+
+static int
+nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
+ struct buffer_head *bh,
+ void (*init_block)(struct inode *,
+ struct buffer_head *, void *))
+{
+ struct nilfs_inode_info *ii = NILFS_I(inode);
+ void *kaddr;
+ int ret;
+
+ /* Caller exclude read accesses using page lock */
+
+ /* set_buffer_new(bh); */
+ bh->b_blocknr = 0;
+
+ ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
+ if (unlikely(ret))
+ return ret;
+
+ set_buffer_mapped(bh);
+
+ kaddr = kmap_atomic(bh->b_page, KM_USER0);
+ memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits);
+ if (init_block)
+ init_block(inode, bh, kaddr);
+ flush_dcache_page(bh->b_page);
+ kunmap_atomic(kaddr, KM_USER0);
+
+ set_buffer_uptodate(bh);
+ nilfs_mark_buffer_dirty(bh);
+ nilfs_mdt_mark_dirty(inode);
+ return 0;
+}
+
+static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
+ struct buffer_head **out_bh,
+ void (*init_block)(struct inode *,
+ struct buffer_head *,
+ void *))
+{
+ struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
+ struct nilfs_sb_info *writer = NULL;
+ struct super_block *sb = inode->i_sb;
+ struct nilfs_transaction_info ti;
+ struct buffer_head *bh;
+ int err;
+
+ if (!sb) {
+ writer = nilfs_get_writer(nilfs);
+ if (!writer) {
+ err = -EROFS;
+ goto out;
+ }
+ sb = writer->s_super;
+ }
+
+ nilfs_transaction_begin(sb, &ti, 0);
+
+ err = -ENOMEM;
+ bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
+ if (unlikely(!bh))
+ goto failed_unlock;
+
+ err = -EEXIST;
+ if (buffer_uptodate(bh) || buffer_mapped(bh))
+ goto failed_bh;
+#if 0
+ /* The uptodate flag is not protected by the page lock, but
+ the mapped flag is. Thus, we don't have to wait the buffer. */
+ wait_on_buffer(bh);
+ if (buffer_uptodate(bh))
+ goto failed_bh;
+#endif
+
+ bh->b_bdev = nilfs->ns_bdev;
+ err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
+ if (likely(!err)) {
+ get_bh(bh);
+ *out_bh = bh;
+ }
+
+ failed_bh:
+ unlock_page(bh->b_page);
+ page_cache_release(bh->b_page);
+ brelse(bh);
+
+ failed_unlock:
+ nilfs_transaction_end(sb, !err);
+ if (writer)
+ nilfs_put_writer(nilfs);
+ out:
+ return err;
+}
+
+static int
+nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
+ int mode, struct buffer_head **out_bh)
+{
+ struct buffer_head *bh;
+ unsigned long blknum = 0;
+ int ret = -ENOMEM;
+
+ bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
+ if (unlikely(!bh))
+ goto failed;
+
+ ret = -EEXIST; /* internal code */
+ if (buffer_uptodate(bh))
+ goto out;
+
+ if (mode == READA) {
+ if (!trylock_buffer(bh)) {
+ ret = -EBUSY;
+ goto failed_bh;
+ }
+ } else {
+ BUG_ON(mode != READ);
+ lock_buffer(bh);
+ }
+
+ if (buffer_uptodate(bh)) {
+ unlock_buffer(bh);
+ goto out;
+ }
+ if (!buffer_mapped(bh)) { /* unused buffer */
+ ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff,
+ &blknum);
+ if (unlikely(ret)) {
+ unlock_buffer(bh);
+ goto failed_bh;
+ }
+ bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
+ bh->b_blocknr = blknum;
+ set_buffer_mapped(bh);
+ }
+
+ bh->b_end_io = end_buffer_read_sync;
+ get_bh(bh);
+ submit_bh(mode, bh);
+ ret = 0;
+ out:
+ get_bh(bh);
+ *out_bh = bh;
+
+ failed_bh:
+ unlock_page(bh->b_page);
+ page_cache_release(bh->b_page);
+ brelse(bh);
+ failed:
+ return ret;
+}
+
+static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
+ struct buffer_head **out_bh)
+{
+ struct buffer_head *first_bh, *bh;
+ unsigned long blkoff;
+ int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
+ int err;
+
+ err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
+ if (err == -EEXIST) /* internal code */
+ goto out;
+
+ if (unlikely(err))
+ goto failed;
+
+ blkoff = block + 1;
+ for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
+ err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
+ if (likely(!err || err == -EEXIST))
+ brelse(bh);
+ else if (err != -EBUSY)
+ break; /* abort readahead if bmap lookup failed */
+
+ if (!buffer_locked(first_bh))
+ goto out_no_wait;
+ }
+
+ wait_on_buffer(first_bh);
+
+ out_no_wait:
+ err = -EIO;
+ if (!buffer_uptodate(first_bh))
+ goto failed_bh;
+ out:
+ *out_bh = first_bh;
+ return 0;
+
+ failed_bh:
+ brelse(first_bh);
+ failed:
+ return err;
+}
+
+/**
+ * nilfs_mdt_get_block - read or create a buffer on meta data file.
+ * @inode: inode of the meta data file
+ * @blkoff: block offset
+ * @create: create flag
+ * @init_block: initializer used for newly allocated block
+ * @out_bh: output of a pointer to the buffer_head
+ *
+ * nilfs_mdt_get_block() looks up the specified buffer and tries to create
+ * a new buffer if @create is not zero. On success, the returned buffer is
+ * assured to be either existing or formatted using a buffer lock on success.
+ * @out_bh is substituted only when zero is returned.
+ *
+ * Return Value: On success, it returns 0. On error, the following negative
+ * error code is returned.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ *
+ * %-EIO - I/O error
+ *
+ * %-ENOENT - the specified block does not exist (hole block)
+ *
+ * %-EINVAL - bmap is broken. (the caller should call nilfs_error())
+ *
+ * %-EROFS - Read only filesystem (for create mode)
+ */
+int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
+ void (*init_block)(struct inode *,
+ struct buffer_head *, void *),
+ struct buffer_head **out_bh)
+{
+ int ret;
+
+ /* Should be rewritten with merging nilfs_mdt_read_block() */
+ retry:
+ ret = nilfs_mdt_read_block(inode, blkoff, out_bh);
+ if (!create || ret != -ENOENT)
+ return ret;
+
+ ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
+ if (unlikely(ret == -EEXIST)) {
+ /* create = 0; */ /* limit read-create loop retries */
+ goto retry;
+ }
+ return ret;
+}
+
+/**
+ * nilfs_mdt_delete_block - make a hole on the meta data file.
+ * @inode: inode of the meta data file
+ * @block: block offset
+ *
+ * Return Value: On success, zero is returned.
+ * On error, one of the following negative error code is returned.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ *
+ * %-EIO - I/O error
+ *
+ * %-EINVAL - bmap is broken. (the caller should call nilfs_error())
+ */
+int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
+{
+ struct nilfs_inode_info *ii = NILFS_I(inode);
+ int err;
+
+ err = nilfs_bmap_delete(ii->i_bmap, block);
+ if (likely(!err)) {
+ nilfs_mdt_mark_dirty(inode);
+ nilfs_mdt_forget_block(inode, block);
+ }
+ return err;
+}
+
+/**
+ * nilfs_mdt_forget_block - discard dirty state and try to remove the page
+ * @inode: inode of the meta data file
+ * @block: block offset
+ *
+ * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
+ * tries to release the page including the buffer from a page cache.
+ *
+ * Return Value: On success, 0 is returned. On error, one of the following
+ * negative error code is returned.
+ *
+ * %-EBUSY - page has an active buffer.
+ *
+ * %-ENOENT - page cache has no page addressed by the offset.
+ */
+int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
+{
+ pgoff_t index = (pgoff_t)block >>
+ (PAGE_CACHE_SHIFT - inode->i_blkbits);
+ struct page *page;
+ unsigned long first_block;
+ int ret = 0;
+ int still_dirty;
+
+ page = find_lock_page(inode->i_mapping, index);
+ if (!page)
+ return -ENOENT;
+
+ wait_on_page_writeback(page);
+
+ first_block = (unsigned long)index <<
+ (PAGE_CACHE_SHIFT - inode->i_blkbits);
+ if (page_has_buffers(page)) {
+ struct buffer_head *bh;
+
+ bh = nilfs_page_get_nth_block(page, block - first_block);
+ nilfs_forget_buffer(bh);
+ }
+ still_dirty = PageDirty(page);
+ unlock_page(page);
+ page_cache_release(page);
+
+ if (still_dirty ||
+ invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
+ ret = -EBUSY;
+ return ret;
+}
+
+/**
+ * nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty.
+ * @inode: inode of the meta data file
+ * @block: block offset
+ *
+ * Return Value: On success, it returns 0. On error, the following negative
+ * error code is returned.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ *
+ * %-EIO - I/O error
+ *
+ * %-ENOENT - the specified block does not exist (hole block)
+ *
+ * %-EINVAL - bmap is broken. (the caller should call nilfs_error())
+ */
+int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block)
+{
+ struct buffer_head *bh;
+ int err;
+
+ err = nilfs_mdt_read_block(inode, block, &bh);
+ if (unlikely(err))
+ return err;
+ nilfs_mark_buffer_dirty(bh);
+ nilfs_mdt_mark_dirty(inode);
+ brelse(bh);
+ return 0;
+}
+
+int nilfs_mdt_fetch_dirty(struct inode *inode)
+{
+ struct nilfs_inode_info *ii = NILFS_I(inode);
+
+ if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
+ set_bit(NILFS_I_DIRTY, &ii->i_state);
+ return 1;
+ }
+ return test_bit(NILFS_I_DIRTY, &ii->i_state);
+}
+
+static int
+nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
+{
+ struct inode *inode = container_of(page->mapping,
+ struct inode, i_data);
+ struct super_block *sb = inode->i_sb;
+ struct nilfs_sb_info *writer = NULL;
+ int err = 0;
+
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+
+ if (page->mapping->assoc_mapping)
+ return 0; /* Do not request flush for shadow page cache */
+ if (!sb) {
+ writer = nilfs_get_writer(NILFS_MDT(inode)->mi_nilfs);
+ if (!writer)
+ return -EROFS;
+ sb = writer->s_super;
+ }
+
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ err = nilfs_construct_segment(sb);
+ else if (wbc->for_reclaim)
+ nilfs_flush_segment(sb, inode->i_ino);
+
+ if (writer)
+ nilfs_put_writer(NILFS_MDT(inode)->mi_nilfs);
+ return err;
+}
+
+
+static struct address_space_operations def_mdt_aops = {
+ .writepage = nilfs_mdt_write_page,
+};
+
+static struct inode_operations def_mdt_iops;
+static struct file_operations def_mdt_fops;
+
+/*
+ * NILFS2 uses pseudo inodes for meta data files such as DAT, cpfile, sufile,
+ * ifile, or gcinodes. This allows the B-tree code and segment constructor
+ * to treat them like regular files, and this helps to simplify the
+ * implementation.
+ * On the other hand, some of the pseudo inodes have an irregular point:
+ * They don't have valid inode->i_sb pointer because their lifetimes are
+ * longer than those of the super block structs; they may continue for
+ * several consecutive mounts/umounts. This would need discussions.
+ */
+struct inode *
+nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
+ ino_t ino, gfp_t gfp_mask)
+{
+ struct inode *inode = nilfs_alloc_inode(sb);
+
+ if (!inode)
+ return NULL;
+ else {
+ struct address_space * const mapping = &inode->i_data;
+ struct nilfs_mdt_info *mi = kzalloc(sizeof(*mi), GFP_NOFS);
+
+ if (!mi) {
+ nilfs_destroy_inode(inode);
+ return NULL;
+ }
+ mi->mi_nilfs = nilfs;
+ init_rwsem(&mi->mi_sem);
+
+ inode->i_sb = sb; /* sb may be NULL for some meta data files */
+ inode->i_blkbits = nilfs->ns_blocksize_bits;
+ inode->i_flags = 0;
+ atomic_set(&inode->i_count, 1);
+ inode->i_nlink = 1;
+ inode->i_ino = ino;
+ inode->i_mode = S_IFREG;
+ inode->i_private = mi;
+
+#ifdef INIT_UNUSED_INODE_FIELDS
+ atomic_set(&inode->i_writecount, 0);
+ inode->i_size = 0;
+ inode->i_blocks = 0;
+ inode->i_bytes = 0;
+ inode->i_generation = 0;
+#ifdef CONFIG_QUOTA
+ memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
+#endif
+ inode->i_pipe = NULL;
+ inode->i_bdev = NULL;
+ inode->i_cdev = NULL;
+ inode->i_rdev = 0;
+#ifdef CONFIG_SECURITY
+ inode->i_security = NULL;
+#endif
+ inode->dirtied_when = 0;
+
+ INIT_LIST_HEAD(&inode->i_list);
+ INIT_LIST_HEAD(&inode->i_sb_list);
+ inode->i_state = 0;
+#endif
+
+ spin_lock_init(&inode->i_lock);
+ mutex_init(&inode->i_mutex);
+ init_rwsem(&inode->i_alloc_sem);
+
+ mapping->host = NULL; /* instead of inode */
+ mapping->flags = 0;
+ mapping_set_gfp_mask(mapping, gfp_mask);
+ mapping->assoc_mapping = NULL;
+ mapping->backing_dev_info = nilfs->ns_bdi;
+
+ inode->i_mapping = mapping;
+ }
+
+ return inode;
+}
+
+struct inode *nilfs_mdt_new(struct the_nilfs *nilfs, struct super_block *sb,
+ ino_t ino, gfp_t gfp_mask)
+{
+ struct inode *inode = nilfs_mdt_new_common(nilfs, sb, ino, gfp_mask);
+
+ if (!inode)
+ return NULL;
+
+ inode->i_op = &def_mdt_iops;
+ inode->i_fop = &def_mdt_fops;
+ inode->i_mapping->a_ops = &def_mdt_aops;
+ return inode;
+}
+
+void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size,
+ unsigned header_size)
+{
+ struct nilfs_mdt_info *mi = NILFS_MDT(inode);
+
+ mi->mi_entry_size = entry_size;
+ mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
+ mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
+}
+
+void nilfs_mdt_set_shadow(struct inode *orig, struct inode *shadow)
+{
+ shadow->i_mapping->assoc_mapping = orig->i_mapping;
+ NILFS_I(shadow)->i_btnode_cache.assoc_mapping =
+ &NILFS_I(orig)->i_btnode_cache;
+}
+
+void nilfs_mdt_clear(struct inode *inode)
+{
+ struct nilfs_inode_info *ii = NILFS_I(inode);
+
+ invalidate_mapping_pages(inode->i_mapping, 0, -1);
+ truncate_inode_pages(inode->i_mapping, 0);
+
+ nilfs_bmap_clear(ii->i_bmap);
+ nilfs_btnode_cache_clear(&ii->i_btnode_cache);
+}
+
+void nilfs_mdt_destroy(struct inode *inode)
+{
+ struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
+
+ kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
+ kfree(mdi);
+ nilfs_destroy_inode(inode);
+}
diff --git a/fs/nilfs2/mdt.h b/fs/nilfs2/mdt.h
new file mode 100644
index 0000000..df683e0
--- /dev/null
+++ b/fs/nilfs2/mdt.h
@@ -0,0 +1,125 @@
+/*
+ * mdt.h - NILFS meta data file prototype and definitions
+ *
+ * Copyright (C) 2005-2008 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 Ryusuke Konishi <ryusuke@xxxxxxxx>
+ */
+
+#ifndef _NILFS_MDT_H
+#define _NILFS_MDT_H
+
+#include <linux/buffer_head.h>
+#include <linux/blockgroup_lock.h>
+#include "nilfs.h"
+#include "page.h"
+
+/**
+ * struct nilfs_mdt_info - on-memory private data of meta data files
+ * @mi_nilfs: back pointer to the_nilfs struct
+ * @mi_sem: reader/writer semaphore for meta data operations
+ * @mi_bgl: per-blockgroup locking
+ * @mi_entry_size: size of an entry
+ * @mi_first_entry_offset: offset to the first entry
+ * @mi_entries_per_block: number of entries in a block
+ * @mi_blocks_per_group: number of blocks in a group
+ * @mi_blocks_per_desc_block: number of blocks per descriptor block
+ */
+struct nilfs_mdt_info {
+ struct the_nilfs *mi_nilfs;
+ struct rw_semaphore mi_sem;
+ struct blockgroup_lock *mi_bgl;
+ unsigned mi_entry_size;
+ unsigned mi_first_entry_offset;
+ unsigned long mi_entries_per_block;
+ unsigned long mi_blocks_per_group;
+ unsigned long mi_blocks_per_desc_block;
+};
+
+static inline struct nilfs_mdt_info *NILFS_MDT(const struct inode *inode)
+{
+ return inode->i_private;
+}
+
+static inline struct the_nilfs *NILFS_I_NILFS(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+
+ return sb ? NILFS_SB(sb)->s_nilfs : NILFS_MDT(inode)->mi_nilfs;
+}
+
+/* Default GFP flags using highmem */
+#define NILFS_MDT_GFP (__GFP_WAIT | __GFP_IO | __GFP_HIGHMEM)
+
+int nilfs_mdt_get_block(struct inode *, unsigned long, int,
+ void (*init_block)(struct inode *,
+ struct buffer_head *, void *),
+ struct buffer_head **);
+int nilfs_mdt_delete_block(struct inode *, unsigned long);
+int nilfs_mdt_forget_block(struct inode *, unsigned long);
+int nilfs_mdt_mark_block_dirty(struct inode *, unsigned long);
+int nilfs_mdt_fetch_dirty(struct inode *);
+
+struct inode *nilfs_mdt_new(struct the_nilfs *, struct super_block *, ino_t,
+ gfp_t);
+struct inode *nilfs_mdt_new_common(struct the_nilfs *, struct super_block *,
+ ino_t, gfp_t);
+void nilfs_mdt_destroy(struct inode *);
+void nilfs_mdt_clear(struct inode *);
+void nilfs_mdt_set_entry_size(struct inode *, unsigned, unsigned);
+void nilfs_mdt_set_shadow(struct inode *, struct inode *);
+
+
+#define nilfs_mdt_mark_buffer_dirty(bh) nilfs_mark_buffer_dirty(bh)
+
+static inline void nilfs_mdt_mark_dirty(struct inode *inode)
+{
+ if (!test_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state))
+ set_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state);
+}
+
+static inline void nilfs_mdt_clear_dirty(struct inode *inode)
+{
+ clear_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state);
+}
+
+static inline __u64 nilfs_mdt_cno(struct inode *inode)
+{
+ return NILFS_MDT(inode)->mi_nilfs->ns_cno;
+}
+
+#define nilfs_mdt_bgl_lock(inode, bg) \
+ (&NILFS_MDT(inode)->mi_bgl->locks[(bg) & (NR_BG_LOCKS-1)].lock)
+
+
+static inline int
+nilfs_mdt_read_inode_direct(struct inode *inode, struct buffer_head *bh,
+ unsigned n)
+{
+ return nilfs_read_inode_common(
+ inode, (struct nilfs_inode *)(bh->b_data + n));
+}
+
+static inline void
+nilfs_mdt_write_inode_direct(struct inode *inode, struct buffer_head *bh,
+ unsigned n)
+{
+ nilfs_write_inode_common(
+ inode, (struct nilfs_inode *)(bh->b_data + n), 1);
+}
+
+#endif /* _NILFS_MDT_H */
--
1.5.6.3
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