fs/sysv/inode.c - maze/linux - Git at Google

 /*
  *  linux/fs/sysv/inode.c
  *
  *  minix/inode.c
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
  *  xenix/inode.c
  *  Copyright (C) 1992  Doug Evans
  *
  *  coh/inode.c
  *  Copyright (C) 1993  Pascal Haible, Bruno Haible
  *
  *  sysv/inode.c
  *  Copyright (C) 1993  Paul B. Monday
  *
  *  sysv/inode.c
  *  Copyright (C) 1993  Bruno Haible
  *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
  *
  *  This file contains code for allocating/freeing inodes and for read/writing
  *  the superblock.
  */

 #include <linux/smp_lock.h>
 #include <linux/highuid.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/buffer_head.h>
 #include <linux/vfs.h>
 #include <asm/byteorder.h>
 #include "sysv.h"

 /* This is only called on sync() and umount(), when s_dirt=1. */
 static void sysv_write_super(struct super_block *sb)
 {
 	struct sysv_sb_info *sbi = SYSV_SB(sb);
 	unsigned long time = get_seconds(), old_time;

 	lock_kernel();
 	if (sb->s_flags & MS_RDONLY)
 		goto clean;

 	/*
 	 * If we are going to write out the super block,
 	 * then attach current time stamp.
 	 * But if the filesystem was marked clean, keep it clean.
 	 */
 	old_time = fs32_to_cpu(sbi, *sbi->s_sb_time);
 	if (sbi->s_type == FSTYPE_SYSV4) {
 		if (*sbi->s_sb_state == cpu_to_fs32(sbi, 0x7c269d38 - old_time))
 			*sbi->s_sb_state = cpu_to_fs32(sbi, 0x7c269d38 - time);
 		*sbi->s_sb_time = cpu_to_fs32(sbi, time);
 		mark_buffer_dirty(sbi->s_bh2);
 	}
 clean:
 	sb->s_dirt = 0;
 	unlock_kernel();
 }

 static int sysv_remount(struct super_block *sb, int *flags, char *data)
 {
 	struct sysv_sb_info *sbi = SYSV_SB(sb);
 	if (sbi->s_forced_ro)
 		*flags |= MS_RDONLY;
 	if (!(*flags & MS_RDONLY))
 		sb->s_dirt = 1;
 	return 0;
 }

 static void sysv_put_super(struct super_block *sb)
 {
 	struct sysv_sb_info *sbi = SYSV_SB(sb);

 	if (!(sb->s_flags & MS_RDONLY)) {
 		/* XXX ext2 also updates the state here */
 		mark_buffer_dirty(sbi->s_bh1);
 		if (sbi->s_bh1 != sbi->s_bh2)
 			mark_buffer_dirty(sbi->s_bh2);
 	}

 	brelse(sbi->s_bh1);
 	if (sbi->s_bh1 != sbi->s_bh2)
 		brelse(sbi->s_bh2);

 	kfree(sbi);
 }

 static int sysv_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct super_block *sb = dentry->d_sb;
 	struct sysv_sb_info *sbi = SYSV_SB(sb);

 	buf->f_type = sb->s_magic;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = sbi->s_ndatazones;
 	buf->f_bavail = buf->f_bfree = sysv_count_free_blocks(sb);
 	buf->f_files = sbi->s_ninodes;
 	buf->f_ffree = sysv_count_free_inodes(sb);
 	buf->f_namelen = SYSV_NAMELEN;
 	return 0;
 }

 /*
  * NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
  */
 static inline void read3byte(struct sysv_sb_info *sbi,
 	unsigned char * from, unsigned char * to)
 {
 	if (sbi->s_bytesex == BYTESEX_PDP) {
 		to[0] = from[0];
 		to[1] = 0;
 		to[2] = from[1];
 		to[3] = from[2];
 	} else if (sbi->s_bytesex == BYTESEX_LE) {
 		to[0] = from[0];
 		to[1] = from[1];
 		to[2] = from[2];
 		to[3] = 0;
 	} else {
 		to[0] = 0;
 		to[1] = from[0];
 		to[2] = from[1];
 		to[3] = from[2];
 	}
 }

 static inline void write3byte(struct sysv_sb_info *sbi,
 	unsigned char * from, unsigned char * to)
 {
 	if (sbi->s_bytesex == BYTESEX_PDP) {
 		to[0] = from[0];
 		to[1] = from[2];
 		to[2] = from[3];
 	} else if (sbi->s_bytesex == BYTESEX_LE) {
 		to[0] = from[0];
 		to[1] = from[1];
 		to[2] = from[2];
 	} else {
 		to[0] = from[1];
 		to[1] = from[2];
 		to[2] = from[3];
 	}
 }

 static const struct inode_operations sysv_symlink_inode_operations = {
 	.readlink	= generic_readlink,
 	.follow_link	= page_follow_link_light,
 	.put_link	= page_put_link,
 	.getattr	= sysv_getattr,
 };

 void sysv_set_inode(struct inode *inode, dev_t rdev)
 {
 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = &sysv_file_inode_operations;
 		inode->i_fop = &sysv_file_operations;
 		inode->i_mapping->a_ops = &sysv_aops;
 	} else if (S_ISDIR(inode->i_mode)) {
 		inode->i_op = &sysv_dir_inode_operations;
 		inode->i_fop = &sysv_dir_operations;
 		inode->i_mapping->a_ops = &sysv_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (inode->i_blocks) {
 			inode->i_op = &sysv_symlink_inode_operations;
 			inode->i_mapping->a_ops = &sysv_aops;
 		} else
 			inode->i_op = &sysv_fast_symlink_inode_operations;
 	} else
 		init_special_inode(inode, inode->i_mode, rdev);
 }

 static void sysv_read_inode(struct inode *inode)
 {
 	struct super_block * sb = inode->i_sb;
 	struct sysv_sb_info * sbi = SYSV_SB(sb);
 	struct buffer_head * bh;
 	struct sysv_inode * raw_inode;
 	struct sysv_inode_info * si;
 	unsigned int block, ino = inode->i_ino;

 	if (!ino || ino > sbi->s_ninodes) {
 		printk("Bad inode number on dev %s: %d is out of range\n",
 		       inode->i_sb->s_id, ino);
 		goto bad_inode;
 	}
 	raw_inode = sysv_raw_inode(sb, ino, &bh);
 	if (!raw_inode) {
 		printk("Major problem: unable to read inode from dev %s\n",
 		       inode->i_sb->s_id);
 		goto bad_inode;
 	}
 	/* SystemV FS: kludge permissions if ino==SYSV_ROOT_INO ?? */
 	inode->i_mode = fs16_to_cpu(sbi, raw_inode->i_mode);
 	inode->i_uid = (uid_t)fs16_to_cpu(sbi, raw_inode->i_uid);
 	inode->i_gid = (gid_t)fs16_to_cpu(sbi, raw_inode->i_gid);
 	inode->i_nlink = fs16_to_cpu(sbi, raw_inode->i_nlink);
 	inode->i_size = fs32_to_cpu(sbi, raw_inode->i_size);
 	inode->i_atime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_atime);
 	inode->i_mtime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_mtime);
 	inode->i_ctime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_ctime);
 	inode->i_ctime.tv_nsec = 0;
 	inode->i_atime.tv_nsec = 0;
 	inode->i_mtime.tv_nsec = 0;
 	inode->i_blocks = 0;

 	si = SYSV_I(inode);
 	for (block = 0; block < 10+1+1+1; block++)
 		read3byte(sbi, &raw_inode->i_data[3*block],
 				(u8 *)&si->i_data[block]);
 	brelse(bh);
 	si->i_dir_start_lookup = 0;
 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 		sysv_set_inode(inode,
 			       old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
 	else
 		sysv_set_inode(inode, 0);
 	return;

 bad_inode:
 	make_bad_inode(inode);
 	return;
 }

 static struct buffer_head * sysv_update_inode(struct inode * inode)
 {
 	struct super_block * sb = inode->i_sb;
 	struct sysv_sb_info * sbi = SYSV_SB(sb);
 	struct buffer_head * bh;
 	struct sysv_inode * raw_inode;
 	struct sysv_inode_info * si;
 	unsigned int ino, block;

 	ino = inode->i_ino;
 	if (!ino || ino > sbi->s_ninodes) {
 		printk("Bad inode number on dev %s: %d is out of range\n",
 		       inode->i_sb->s_id, ino);
 		return NULL;
 	}
 	raw_inode = sysv_raw_inode(sb, ino, &bh);
 	if (!raw_inode) {
 		printk("unable to read i-node block\n");
 		return NULL;
 	}

 	raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
 	raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(inode->i_uid));
 	raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(inode->i_gid));
 	raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
 	raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
 	raw_inode->i_atime = cpu_to_fs32(sbi, inode->i_atime.tv_sec);
 	raw_inode->i_mtime = cpu_to_fs32(sbi, inode->i_mtime.tv_sec);
 	raw_inode->i_ctime = cpu_to_fs32(sbi, inode->i_ctime.tv_sec);

 	si = SYSV_I(inode);
 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 		si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
 	for (block = 0; block < 10+1+1+1; block++)
 		write3byte(sbi, (u8 *)&si->i_data[block],
 			&raw_inode->i_data[3*block]);
 	mark_buffer_dirty(bh);
 	return bh;
 }

 int sysv_write_inode(struct inode * inode, int wait)
 {
 	struct buffer_head *bh;
 	lock_kernel();
 	bh = sysv_update_inode(inode);
 	brelse(bh);
 	unlock_kernel();
 	return 0;
 }

 int sysv_sync_inode(struct inode * inode)
 {
         int err = 0;
         struct buffer_head *bh;

         bh = sysv_update_inode(inode);
         if (bh && buffer_dirty(bh)) {
                 sync_dirty_buffer(bh);
                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
                         printk ("IO error syncing sysv inode [%s:%08lx]\n",
                                 inode->i_sb->s_id, inode->i_ino);
                         err = -1;
                 }
         }
         else if (!bh)
                 err = -1;
         brelse (bh);
         return err;
 }

 static void sysv_delete_inode(struct inode *inode)
 {
 	truncate_inode_pages(&inode->i_data, 0);
 	inode->i_size = 0;
 	sysv_truncate(inode);
 	lock_kernel();
 	sysv_free_inode(inode);
 	unlock_kernel();
 }

 static struct kmem_cache *sysv_inode_cachep;

 static struct inode *sysv_alloc_inode(struct super_block *sb)
 {
 	struct sysv_inode_info *si;

 	si = kmem_cache_alloc(sysv_inode_cachep, GFP_KERNEL);
 	if (!si)
 		return NULL;
 	return &si->vfs_inode;
 }

 static void sysv_destroy_inode(struct inode *inode)
 {
 	kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
 }

 static void init_once(void *p, struct kmem_cache *cachep, unsigned long flags)
 {
 	struct sysv_inode_info *si = (struct sysv_inode_info *)p;

 	if (flags & SLAB_CTOR_CONSTRUCTOR)
 		inode_init_once(&si->vfs_inode);
 }

 const struct super_operations sysv_sops = {
 	.alloc_inode	= sysv_alloc_inode,
 	.destroy_inode	= sysv_destroy_inode,
 	.read_inode	= sysv_read_inode,
 	.write_inode	= sysv_write_inode,
 	.delete_inode	= sysv_delete_inode,
 	.put_super	= sysv_put_super,
 	.write_super	= sysv_write_super,
 	.remount_fs	= sysv_remount,
 	.statfs		= sysv_statfs,
 };

 int __init sysv_init_icache(void)
 {
 	sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
 			sizeof(struct sysv_inode_info), 0,
 			SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
 			init_once, NULL);
 	if (!sysv_inode_cachep)
 		return -ENOMEM;
 	return 0;
 }

 void sysv_destroy_icache(void)
 {
 	kmem_cache_destroy(sysv_inode_cachep);
 }
	/*
	* linux/fs/sysv/inode.c
	*
	* minix/inode.c
	* Copyright (C) 1991, 1992 Linus Torvalds
	*
	* xenix/inode.c
	* Copyright (C) 1992 Doug Evans
	*
	* coh/inode.c
	* Copyright (C) 1993 Pascal Haible, Bruno Haible
	*
	* sysv/inode.c
	* Copyright (C) 1993 Paul B. Monday
	*
	* sysv/inode.c
	* Copyright (C) 1993 Bruno Haible
	* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
	*
	* This file contains code for allocating/freeing inodes and for read/writing
	* the superblock.
	*/

	#include <linux/smp_lock.h>
	#include <linux/highuid.h>
	#include <linux/slab.h>
	#include <linux/init.h>
	#include <linux/buffer_head.h>
	#include <linux/vfs.h>
	#include <asm/byteorder.h>
	#include "sysv.h"

	/* This is only called on sync() and umount(), when s_dirt=1. */
	static void sysv_write_super(struct super_block *sb)
	{
	struct sysv_sb_info *sbi = SYSV_SB(sb);
	unsigned long time = get_seconds(), old_time;

	lock_kernel();
	if (sb->s_flags & MS_RDONLY)
	goto clean;

	/*
	* If we are going to write out the super block,
	* then attach current time stamp.
	* But if the filesystem was marked clean, keep it clean.
	*/
	old_time = fs32_to_cpu(sbi, *sbi->s_sb_time);
	if (sbi->s_type == FSTYPE_SYSV4) {
	if (*sbi->s_sb_state == cpu_to_fs32(sbi, 0x7c269d38 - old_time))
	*sbi->s_sb_state = cpu_to_fs32(sbi, 0x7c269d38 - time);
	*sbi->s_sb_time = cpu_to_fs32(sbi, time);
	mark_buffer_dirty(sbi->s_bh2);
	}
	clean:
	sb->s_dirt = 0;
	unlock_kernel();
	}

	static int sysv_remount(struct super_block sb, int flags, char *data)
	{
	struct sysv_sb_info *sbi = SYSV_SB(sb);
	if (sbi->s_forced_ro)
	*flags \|= MS_RDONLY;
	if (!(*flags & MS_RDONLY))
	sb->s_dirt = 1;
	return 0;
	}

	static void sysv_put_super(struct super_block *sb)
	{
	struct sysv_sb_info *sbi = SYSV_SB(sb);

	if (!(sb->s_flags & MS_RDONLY)) {
	/* XXX ext2 also updates the state here */
	mark_buffer_dirty(sbi->s_bh1);
	if (sbi->s_bh1 != sbi->s_bh2)
	mark_buffer_dirty(sbi->s_bh2);
	}

	brelse(sbi->s_bh1);
	if (sbi->s_bh1 != sbi->s_bh2)
	brelse(sbi->s_bh2);

	kfree(sbi);
	}

	static int sysv_statfs(struct dentry dentry, struct kstatfs buf)
	{
	struct super_block *sb = dentry->d_sb;
	struct sysv_sb_info *sbi = SYSV_SB(sb);

	buf->f_type = sb->s_magic;
	buf->f_bsize = sb->s_blocksize;
	buf->f_blocks = sbi->s_ndatazones;
	buf->f_bavail = buf->f_bfree = sysv_count_free_blocks(sb);
	buf->f_files = sbi->s_ninodes;
	buf->f_ffree = sysv_count_free_inodes(sb);
	buf->f_namelen = SYSV_NAMELEN;
	return 0;
	}

	/*
	* NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
	*/
	static inline void read3byte(struct sysv_sb_info *sbi,
	unsigned char * from, unsigned char * to)
	{
	if (sbi->s_bytesex == BYTESEX_PDP) {
	to[0] = from[0];
	to[1] = 0;
	to[2] = from[1];
	to[3] = from[2];
	} else if (sbi->s_bytesex == BYTESEX_LE) {
	to[0] = from[0];
	to[1] = from[1];
	to[2] = from[2];
	to[3] = 0;
	} else {
	to[0] = 0;
	to[1] = from[0];
	to[2] = from[1];
	to[3] = from[2];
	}
	}

	static inline void write3byte(struct sysv_sb_info *sbi,
	unsigned char * from, unsigned char * to)
	{
	if (sbi->s_bytesex == BYTESEX_PDP) {
	to[0] = from[0];
	to[1] = from[2];
	to[2] = from[3];
	} else if (sbi->s_bytesex == BYTESEX_LE) {
	to[0] = from[0];
	to[1] = from[1];
	to[2] = from[2];
	} else {
	to[0] = from[1];
	to[1] = from[2];
	to[2] = from[3];
	}
	}

	static const struct inode_operations sysv_symlink_inode_operations = {
	.readlink = generic_readlink,
	.follow_link = page_follow_link_light,
	.put_link = page_put_link,
	.getattr = sysv_getattr,
	};

	void sysv_set_inode(struct inode *inode, dev_t rdev)
	{
	if (S_ISREG(inode->i_mode)) {
	inode->i_op = &sysv_file_inode_operations;
	inode->i_fop = &sysv_file_operations;
	inode->i_mapping->a_ops = &sysv_aops;
	} else if (S_ISDIR(inode->i_mode)) {
	inode->i_op = &sysv_dir_inode_operations;
	inode->i_fop = &sysv_dir_operations;
	inode->i_mapping->a_ops = &sysv_aops;
	} else if (S_ISLNK(inode->i_mode)) {
	if (inode->i_blocks) {
	inode->i_op = &sysv_symlink_inode_operations;
	inode->i_mapping->a_ops = &sysv_aops;
	} else
	inode->i_op = &sysv_fast_symlink_inode_operations;
	} else
	init_special_inode(inode, inode->i_mode, rdev);
	}

	static void sysv_read_inode(struct inode *inode)
	{
	struct super_block * sb = inode->i_sb;
	struct sysv_sb_info * sbi = SYSV_SB(sb);
	struct buffer_head * bh;
	struct sysv_inode * raw_inode;
	struct sysv_inode_info * si;
	unsigned int block, ino = inode->i_ino;

	if (!ino \|\| ino > sbi->s_ninodes) {
	printk("Bad inode number on dev %s: %d is out of range\n",
	inode->i_sb->s_id, ino);
	goto bad_inode;
	}
	raw_inode = sysv_raw_inode(sb, ino, &bh);
	if (!raw_inode) {
	printk("Major problem: unable to read inode from dev %s\n",
	inode->i_sb->s_id);
	goto bad_inode;
	}
	/* SystemV FS: kludge permissions if ino==SYSV_ROOT_INO ?? */
	inode->i_mode = fs16_to_cpu(sbi, raw_inode->i_mode);
	inode->i_uid = (uid_t)fs16_to_cpu(sbi, raw_inode->i_uid);
	inode->i_gid = (gid_t)fs16_to_cpu(sbi, raw_inode->i_gid);
	inode->i_nlink = fs16_to_cpu(sbi, raw_inode->i_nlink);
	inode->i_size = fs32_to_cpu(sbi, raw_inode->i_size);
	inode->i_atime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_atime);
	inode->i_mtime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_mtime);
	inode->i_ctime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_ctime);
	inode->i_ctime.tv_nsec = 0;
	inode->i_atime.tv_nsec = 0;
	inode->i_mtime.tv_nsec = 0;
	inode->i_blocks = 0;

	si = SYSV_I(inode);
	for (block = 0; block < 10+1+1+1; block++)
	read3byte(sbi, &raw_inode->i_data[3*block],
	(u8 *)&si->i_data[block]);
	brelse(bh);
	si->i_dir_start_lookup = 0;
	if (S_ISCHR(inode->i_mode) \|\| S_ISBLK(inode->i_mode))
	sysv_set_inode(inode,
	old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
	else
	sysv_set_inode(inode, 0);
	return;

	bad_inode:
	make_bad_inode(inode);
	return;
	}

	static struct buffer_head * sysv_update_inode(struct inode * inode)
	{
	struct super_block * sb = inode->i_sb;
	struct sysv_sb_info * sbi = SYSV_SB(sb);
	struct buffer_head * bh;
	struct sysv_inode * raw_inode;
	struct sysv_inode_info * si;
	unsigned int ino, block;

	ino = inode->i_ino;
	if (!ino \|\| ino > sbi->s_ninodes) {
	printk("Bad inode number on dev %s: %d is out of range\n",
	inode->i_sb->s_id, ino);
	return NULL;
	}
	raw_inode = sysv_raw_inode(sb, ino, &bh);
	if (!raw_inode) {
	printk("unable to read i-node block\n");
	return NULL;
	}

	raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
	raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(inode->i_uid));
	raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(inode->i_gid));
	raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
	raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
	raw_inode->i_atime = cpu_to_fs32(sbi, inode->i_atime.tv_sec);
	raw_inode->i_mtime = cpu_to_fs32(sbi, inode->i_mtime.tv_sec);
	raw_inode->i_ctime = cpu_to_fs32(sbi, inode->i_ctime.tv_sec);

	si = SYSV_I(inode);
	if (S_ISCHR(inode->i_mode) \|\| S_ISBLK(inode->i_mode))
	si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
	for (block = 0; block < 10+1+1+1; block++)
	write3byte(sbi, (u8 *)&si->i_data[block],
	&raw_inode->i_data[3*block]);
	mark_buffer_dirty(bh);
	return bh;
	}

	int sysv_write_inode(struct inode * inode, int wait)
	{
	struct buffer_head *bh;
	lock_kernel();
	bh = sysv_update_inode(inode);
	brelse(bh);
	unlock_kernel();
	return 0;
	}

	int sysv_sync_inode(struct inode * inode)
	{
	int err = 0;
	struct buffer_head *bh;

	bh = sysv_update_inode(inode);
	if (bh && buffer_dirty(bh)) {
	sync_dirty_buffer(bh);
	if (buffer_req(bh) && !buffer_uptodate(bh)) {
	printk ("IO error syncing sysv inode [%s:%08lx]\n",
	inode->i_sb->s_id, inode->i_ino);
	err = -1;
	}
	}
	else if (!bh)
	err = -1;
	brelse (bh);
	return err;
	}

	static void sysv_delete_inode(struct inode *inode)
	{
	truncate_inode_pages(&inode->i_data, 0);
	inode->i_size = 0;
	sysv_truncate(inode);
	lock_kernel();
	sysv_free_inode(inode);
	unlock_kernel();
	}

	static struct kmem_cache *sysv_inode_cachep;

	static struct inode sysv_alloc_inode(struct super_block sb)
	{
	struct sysv_inode_info *si;

	si = kmem_cache_alloc(sysv_inode_cachep, GFP_KERNEL);
	if (!si)
	return NULL;
	return &si->vfs_inode;
	}

	static void sysv_destroy_inode(struct inode *inode)
	{
	kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
	}

	static void init_once(void p, struct kmem_cache cachep, unsigned long flags)
	{
	struct sysv_inode_info si = (struct sysv_inode_info )p;

	if (flags & SLAB_CTOR_CONSTRUCTOR)
	inode_init_once(&si->vfs_inode);
	}

	const struct super_operations sysv_sops = {
	.alloc_inode = sysv_alloc_inode,
	.destroy_inode = sysv_destroy_inode,
	.read_inode = sysv_read_inode,
	.write_inode = sysv_write_inode,
	.delete_inode = sysv_delete_inode,
	.put_super = sysv_put_super,
	.write_super = sysv_write_super,
	.remount_fs = sysv_remount,
	.statfs = sysv_statfs,
	};

	int __init sysv_init_icache(void)
	{
	sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
	sizeof(struct sysv_inode_info), 0,
	SLAB_RECLAIM_ACCOUNT\|SLAB_MEM_SPREAD,
	init_once, NULL);
	if (!sysv_inode_cachep)
	return -ENOMEM;
	return 0;
	}

	void sysv_destroy_icache(void)
	{
	kmem_cache_destroy(sysv_inode_cachep);
	}