ops_inode.c

linux 内核源代码

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/namei.h>
#include <linux/utsname.h>
#include <linux/mm.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/lm_interface.h>
#include <asm/uaccess.h>

#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "bmap.h"
#include "dir.h"
#include "eaops.h"
#include "eattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "ops_dentry.h"
#include "ops_inode.h"
#include "quota.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"

/**
 * gfs2_create - Create a file
 * @dir: The directory in which to create the file
 * @dentry: The dentry of the new file
 * @mode: The mode of the new file
 *
 * Returns: errno
 */

static int gfs2_create(struct inode *dir, struct dentry *dentry,
		       int mode, struct nameidata *nd)
{
	struct gfs2_inode *dip = GFS2_I(dir);
	struct gfs2_sbd *sdp = GFS2_SB(dir);
	struct gfs2_holder ghs[2];
	struct inode *inode;

	gfs2_holder_init(dip->i_gl, 0, 0, ghs);

	for (;;) {
		inode = gfs2_createi(ghs, &dentry->d_name, S_IFREG | mode, 0);
		if (!IS_ERR(inode)) {
			gfs2_trans_end(sdp);
			if (dip->i_alloc.al_rgd)
				gfs2_inplace_release(dip);
			gfs2_quota_unlock(dip);
			gfs2_alloc_put(dip);
			gfs2_glock_dq_uninit_m(2, ghs);
			mark_inode_dirty(inode);
			break;
		} else if (PTR_ERR(inode) != -EEXIST ||
			   (nd && (nd->intent.open.flags & O_EXCL))) {
			gfs2_holder_uninit(ghs);
			return PTR_ERR(inode);
		}

		inode = gfs2_lookupi(dir, &dentry->d_name, 0, nd);
		if (inode) {
			if (!IS_ERR(inode)) {
				gfs2_holder_uninit(ghs);
				break;
			} else {
				gfs2_holder_uninit(ghs);
				return PTR_ERR(inode);
			}
		}
	}

	d_instantiate(dentry, inode);

	return 0;
}

/**
 * gfs2_lookup - Look up a filename in a directory and return its inode
 * @dir: The directory inode
 * @dentry: The dentry of the new inode
 * @nd: passed from Linux VFS, ignored by us
 *
 * Called by the VFS layer. Lock dir and call gfs2_lookupi()
 *
 * Returns: errno
 */

static struct dentry *gfs2_lookup(struct inode *dir, struct dentry *dentry,
				  struct nameidata *nd)
{
	struct inode *inode = NULL;

	dentry->d_op = &gfs2_dops;

	inode = gfs2_lookupi(dir, &dentry->d_name, 0, nd);
	if (inode && IS_ERR(inode))
		return ERR_PTR(PTR_ERR(inode));

	if (inode)
		return d_splice_alias(inode, dentry);
	d_add(dentry, inode);

	return NULL;
}

/**
 * gfs2_link - Link to a file
 * @old_dentry: The inode to link
 * @dir: Add link to this directory
 * @dentry: The name of the link
 *
 * Link the inode in "old_dentry" into the directory "dir" with the
 * name in "dentry".
 *
 * Returns: errno
 */

static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
		     struct dentry *dentry)
{
	struct gfs2_inode *dip = GFS2_I(dir);
	struct gfs2_sbd *sdp = GFS2_SB(dir);
	struct inode *inode = old_dentry->d_inode;
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_holder ghs[2];
	int alloc_required;
	int error;

	if (S_ISDIR(inode->i_mode))
		return -EPERM;

	gfs2_holder_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + 1);

	error = gfs2_glock_nq_m(2, ghs);
	if (error)
		goto out;

	error = permission(dir, MAY_WRITE | MAY_EXEC, NULL);
	if (error)
		goto out_gunlock;

	error = gfs2_dir_check(dir, &dentry->d_name, NULL);
	switch (error) {
	case -ENOENT:
		break;
	case 0:
		error = -EEXIST;
	default:
		goto out_gunlock;
	}

	error = -EINVAL;
	if (!dip->i_inode.i_nlink)
		goto out_gunlock;
	error = -EFBIG;
	if (dip->i_di.di_entries == (u32)-1)
		goto out_gunlock;
	error = -EPERM;
	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
		goto out_gunlock;
	error = -EINVAL;
	if (!ip->i_inode.i_nlink)
		goto out_gunlock;
	error = -EMLINK;
	if (ip->i_inode.i_nlink == (u32)-1)
		goto out_gunlock;

	alloc_required = error = gfs2_diradd_alloc_required(dir, &dentry->d_name);
	if (error < 0)
		goto out_gunlock;
	error = 0;

	if (alloc_required) {
		struct gfs2_alloc *al = gfs2_alloc_get(dip);

		error = gfs2_quota_lock(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
		if (error)
			goto out_alloc;

		error = gfs2_quota_check(dip, dip->i_inode.i_uid, dip->i_inode.i_gid);
		if (error)
			goto out_gunlock_q;

		al->al_requested = sdp->sd_max_dirres;

		error = gfs2_inplace_reserve(dip);
		if (error)
			goto out_gunlock_q;

		error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
					 al->al_rgd->rd_length +
					 2 * RES_DINODE + RES_STATFS +
					 RES_QUOTA, 0);
		if (error)
			goto out_ipres;
	} else {
		error = gfs2_trans_begin(sdp, 2 * RES_DINODE + RES_LEAF, 0);
		if (error)
			goto out_ipres;
	}

	error = gfs2_dir_add(dir, &dentry->d_name, ip, IF2DT(inode->i_mode));
	if (error)
		goto out_end_trans;

	error = gfs2_change_nlink(ip, +1);

out_end_trans:
	gfs2_trans_end(sdp);
out_ipres:
	if (alloc_required)
		gfs2_inplace_release(dip);
out_gunlock_q:
	if (alloc_required)
		gfs2_quota_unlock(dip);
out_alloc:
	if (alloc_required)
		gfs2_alloc_put(dip);
out_gunlock:
	gfs2_glock_dq_m(2, ghs);
out:
	gfs2_holder_uninit(ghs);
	gfs2_holder_uninit(ghs + 1);
	if (!error) {
		atomic_inc(&inode->i_count);
		d_instantiate(dentry, inode);
		mark_inode_dirty(inode);
	}
	return error;
}

/**
 * gfs2_unlink - Unlink a file
 * @dir: The inode of the directory containing the file to unlink
 * @dentry: The file itself
 *
 * Unlink a file.  Call gfs2_unlinki()
 *
 * Returns: errno
 */

static int gfs2_unlink(struct inode *dir, struct dentry *dentry)
{
	struct gfs2_inode *dip = GFS2_I(dir);
	struct gfs2_sbd *sdp = GFS2_SB(dir);
	struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
	struct gfs2_holder ghs[3];
	struct gfs2_rgrpd *rgd;
	struct gfs2_holder ri_gh;
	int error;

	error = gfs2_rindex_hold(sdp, &ri_gh);
	if (error)
		return error;

	gfs2_holder_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
	gfs2_holder_init(ip->i_gl,  LM_ST_EXCLUSIVE, 0, ghs + 1);

	rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr);
	gfs2_holder_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, ghs + 2);


	error = gfs2_glock_nq(ghs); /* parent */
	if (error)
		goto out_parent;

	error = gfs2_glock_nq(ghs + 1); /* child */
	if (error)
		goto out_child;

	error = gfs2_glock_nq(ghs + 2); /* rgrp */
	if (error)
		goto out_rgrp;

	error = gfs2_unlink_ok(dip, &dentry->d_name, ip);
	if (error)
		goto out_rgrp;

	error = gfs2_trans_begin(sdp, 2*RES_DINODE + RES_LEAF + RES_RG_BIT, 0);
	if (error)
		goto out_rgrp;

	error = gfs2_dir_del(dip, &dentry->d_name);
        if (error)
                goto out_end_trans;

	error = gfs2_change_nlink(ip, -1);

out_end_trans:
	gfs2_trans_end(sdp);
	gfs2_glock_dq(ghs + 2);
out_rgrp:
	gfs2_holder_uninit(ghs + 2);
	gfs2_glock_dq(ghs + 1);
out_child:
	gfs2_holder_uninit(ghs + 1);
	gfs2_glock_dq(ghs);
out_parent:
	gfs2_holder_uninit(ghs);
	gfs2_glock_dq_uninit(&ri_gh);
	return error;
}

/**
 * gfs2_symlink - Create a symlink
 * @dir: The directory to create the symlink in
 * @dentry: The dentry to put the symlink in
 * @symname: The thing which the link points to
 *
 * Returns: errno
 */

static int gfs2_symlink(struct inode *dir, struct dentry *dentry,
			const char *symname)
{
	struct gfs2_inode *dip = GFS2_I(dir), *ip;
	struct gfs2_sbd *sdp = GFS2_SB(dir);
	struct gfs2_holder ghs[2];
	struct inode *inode;
	struct buffer_head *dibh;
	int size;
	int error;

	/* Must be stuffed with a null terminator for gfs2_follow_link() */
	size = strlen(symname);
	if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode) - 1)
		return -ENAMETOOLONG;

	gfs2_holder_init(dip->i_gl, 0, 0, ghs);

	inode = gfs2_createi(ghs, &dentry->d_name, S_IFLNK | S_IRWXUGO, 0);
	if (IS_ERR(inode)) {
		gfs2_holder_uninit(ghs);
		return PTR_ERR(inode);
	}

	ip = ghs[1].gh_gl->gl_object;

	ip->i_di.di_size = size;

	error = gfs2_meta_inode_buffer(ip, &dibh);

	if (!gfs2_assert_withdraw(sdp, !error)) {
		gfs2_dinode_out(ip, dibh->b_data);
		memcpy(dibh->b_data + sizeof(struct gfs2_dinode), symname,
		       size);
		brelse(dibh);
	}

	gfs2_trans_end(sdp);
	if (dip->i_alloc.al_rgd)
		gfs2_inplace_release(dip);
	gfs2_quota_unlock(dip);
	gfs2_alloc_put(dip);

	gfs2_glock_dq_uninit_m(2, ghs);

	d_instantiate(dentry, inode);
	mark_inode_dirty(inode);

	return 0;
}

/**
 * gfs2_mkdir - Make a directory
 * @dir: The parent directory of the new one
 * @dentry: The dentry of the new directory
 * @mode: The mode of the new directory
 *
 * Returns: errno
 */

static int gfs2_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	struct gfs2_inode *dip = GFS2_I(dir), *ip;
	struct gfs2_sbd *sdp = GFS2_SB(dir);
	struct gfs2_holder ghs[2];
	struct inode *inode;
	struct buffer_head *dibh;
	int error;

	gfs2_holder_init(dip->i_gl, 0, 0, ghs);

	inode = gfs2_createi(ghs, &dentry->d_name, S_IFDIR | mode, 0);
	if (IS_ERR(inode)) {
		gfs2_holder_uninit(ghs);
		return PTR_ERR(inode);
	}

	ip = ghs[1].gh_gl->gl_object;

	ip->i_inode.i_nlink = 2;
	ip->i_di.di_size = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode);
	ip->i_di.di_flags |= GFS2_DIF_JDATA;
	ip->i_di.di_entries = 2;

	error = gfs2_meta_inode_buffer(ip, &dibh);

	if (!gfs2_assert_withdraw(sdp, !error)) {
		struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data;
		struct gfs2_dirent *dent = (struct gfs2_dirent *)(di+1);
		struct qstr str;

		gfs2_str2qstr(&str, ".");
		gfs2_trans_add_bh(ip->i_gl, dibh, 1);
		gfs2_qstr2dirent(&str, GFS2_DIRENT_SIZE(str.len), dent);
		dent->de_inum = di->di_num; /* already GFS2 endian */
		dent->de_type = cpu_to_be16(DT_DIR);
		di->di_entries = cpu_to_be32(1);

		gfs2_str2qstr(&str, "..");
		dent = (struct gfs2_dirent *)((char*)dent + GFS2_DIRENT_SIZE(1));
		gfs2_qstr2dirent(&str, dibh->b_size - GFS2_DIRENT_SIZE(1) - sizeof(struct gfs2_dinode), dent);

		gfs2_inum_out(dip, dent);
		dent->de_type = cpu_to_be16(DT_DIR);

		gfs2_dinode_out(ip, di);

		brelse(dibh);
	}

	error = gfs2_change_nlink(dip, +1);
	gfs2_assert_withdraw(sdp, !error); /* dip already pinned */

	gfs2_trans_end(sdp);
	if (dip->i_alloc.al_rgd)
		gfs2_inplace_release(dip);
	gfs2_quota_unlock(dip);
	gfs2_alloc_put(dip);

	gfs2_glock_dq_uninit_m(2, ghs);

	d_instantiate(dentry, inode);
	mark_inode_dirty(inode);

	return 0;
}

/**
 * gfs2_rmdir - Remove a directory
 * @dir: The parent directory of the directory to be removed
 * @dentry: The dentry of the directory to remove
 *
 * Remove a directory. Call gfs2_rmdiri()
 *
 * Returns: errno
 */

static int gfs2_rmdir(struct inode *dir, struct dentry *dentry)
{
	struct gfs2_inode *dip = GFS2_I(dir);
	struct gfs2_sbd *sdp = GFS2_SB(dir);
	struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
	struct gfs2_holder ghs[3];
	struct gfs2_rgrpd *rgd;
	struct gfs2_holder ri_gh;
	int error;


	error = gfs2_rindex_hold(sdp, &ri_gh);
	if (error)
		return error;
	gfs2_holder_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + 1);

	rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr);
	gfs2_holder_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, ghs + 2);

	error = gfs2_glock_nq_m(3, ghs);
	if (error)
		goto out;

	error = gfs2_unlink_ok(dip, &dentry->d_name, ip);
	if (error)
		goto out_gunlock;

	if (ip->i_di.di_entries < 2) {
		if (gfs2_consist_inode(ip))
			gfs2_dinode_print(ip);
		error = -EIO;
		goto out_gunlock;
	}
	if (ip->i_di.di_entries > 2) {
		error = -ENOTEMPTY;
		goto out_gunlock;
	}

	error = gfs2_trans_begin(sdp, 2 * RES_DINODE + 3 * RES_LEAF + RES_RG_BIT, 0);
	if (error)
		goto out_gunlock;

	error = gfs2_rmdiri(dip, &dentry->d_name, ip);

	gfs2_trans_end(sdp);

out_gunlock:
	gfs2_glock_dq_m(3, ghs);
out:
	gfs2_holder_uninit(ghs);
	gfs2_holder_uninit(ghs + 1);
	gfs2_holder_uninit(ghs + 2);
	gfs2_glock_dq_uninit(&ri_gh);
	return error;
}

/**
 * gfs2_mknod - Make a special file
 * @dir: The directory in which the special file will reside
 * @dentry: The dentry of the special file
 * @mode: The mode of the special file
 * @rdev: The device specification of the special file
 *
 */

static int gfs2_mknod(struct inode *dir, struct dentry *dentry, int mode,
		      dev_t dev)
{
	struct gfs2_inode *dip = GFS2_I(dir);
	struct gfs2_sbd *sdp = GFS2_SB(dir);
	struct gfs2_holder ghs[2];
	struct inode *inode;

	gfs2_holder_init(dip->i_gl, 0, 0, ghs);

	inode = gfs2_createi(ghs, &dentry->d_name, mode, dev);
	if (IS_ERR(inode)) {
		gfs2_holder_uninit(ghs);
		return PTR_ERR(inode);
	}

	gfs2_trans_end(sdp);
	if (dip->i_alloc.al_rgd)
		gfs2_inplace_release(dip);
	gfs2_quota_unlock(dip);
	gfs2_alloc_put(dip);

	gfs2_glock_dq_uninit_m(2, ghs);

	d_instantiate(dentry, inode);
	mark_inode_dirty(inode);

	return 0;
}

/**
 * gfs2_rename - Rename a file
 * @odir: Parent directory of old file name
 * @odentry: The old dentry of the file
 * @ndir: Parent directory of new file name
 * @ndentry: The new dentry of the file
 *
 * Returns: errno
 */

static int gfs2_rename(struct inode *odir, struct dentry *odentry,
		       struct inode *ndir, struct dentry *ndentry)
{
	struct gfs2_inode *odip = GFS2_I(odir);
	struct gfs2_inode *ndip = GFS2_I(ndir);
	struct gfs2_inode *ip = GFS2_I(odentry->d_inode);
	struct gfs2_inode *nip = NULL;
	struct gfs2_sbd *sdp = GFS2_SB(odir);
	struct gfs2_holder ghs[5], r_gh;
	struct gfs2_rgrpd *nrgd;
	unsigned int num_gh;
	int dir_rename = 0;
	int alloc_required;
	unsigned int x;
	int error;

	if (ndentry->d_inode) {
		nip = GFS2_I(ndentry->d_inode);