C++ crfree函数代码示例

static int
zpl_xattr_get(struct inode *ip, const char *name, void *value, size_t size)
{
	znode_t *zp = ITOZ(ip);
	cred_t *cr = CRED();
	int error;

	crhold(cr);
	rw_enter(&zp->z_xattr_lock, RW_READER);
	error = __zpl_xattr_get(ip, name, value, size, cr);
	rw_exit(&zp->z_xattr_lock);
	crfree(cr);

	return (error);
}

static ssize_t
zpl_iter_write_common(struct kiocb *kiocb, const struct iovec *iovp,
    unsigned long nr_segs, size_t count, uio_seg_t seg, size_t skip)
{
	cred_t *cr = CRED();
	struct file *filp = kiocb->ki_filp;
	ssize_t wrote;

	crhold(cr);
	wrote = zpl_write_common_iovec(filp->f_mapping->host, iovp, count,
	    nr_segs, &kiocb->ki_pos, seg, filp->f_flags, cr, skip);
	crfree(cr);

	return (wrote);
}

int
zpl_snapdir_rename(struct inode *sdip, struct dentry *sdentry,
    struct inode *tdip, struct dentry *tdentry)
{
	cred_t *cr = CRED();
	int error;

	crhold(cr);
	error = -zfsctl_snapdir_rename(sdip, dname(sdentry),
	    tdip, dname(tdentry), cr, 0);
	ASSERT3S(error, <=, 0);
	crfree(cr);

	return (error);
}

/*
 * Get the "ucred" of a process.
 */
struct ucred_s *
pgetucred(proc_t *p)
{
	cred_t *cr;
	struct ucred_s *uc;

	mutex_enter(&p->p_crlock);
	cr = p->p_cred;
	crhold(cr);
	mutex_exit(&p->p_crlock);

	uc = cred2ucred(cr, p->p_pid, NULL, CRED());
	crfree(cr);

	return (uc);
}

/*
 * When relabeling a process, call out to the policies for the maximum
 * permission allowed for each object type we know about in its memory space,
 * and revoke access (in the least surprising ways we know) when necessary.
 * The process lock is not held here.
 */
void
mac_proc_vm_revoke(struct thread *td)
{
	struct ucred *cred;

	PROC_LOCK(td->td_proc);
	cred = crhold(td->td_proc->p_ucred);
	PROC_UNLOCK(td->td_proc);

	/* XXX freeze all other threads */
	mac_proc_vm_revoke_recurse(td, cred,
	    &td->td_proc->p_vmspace->vm_map);
	/* XXX allow other threads to continue */

	crfree(cred);
}

static int
zpl_release(struct inode *ip, struct file *filp)
{
	cred_t *cr = CRED();
	int error;

	if (ITOZ(ip)->z_atime_dirty)
		zfs_mark_inode_dirty(ip);

	crhold(cr);
	error = -zfs_close(ip, filp->f_flags, cr);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
zpl_sync_fs(struct super_block *sb, int wait)
{
    fstrans_cookie_t cookie;
    cred_t *cr = CRED();
    int error;

    crhold(cr);
    cookie = spl_fstrans_mark();
    error = -zfs_sync(sb, wait, cr);
    spl_fstrans_unmark(cookie);
    crfree(cr);
    ASSERT3S(error, <=, 0);

    return (error);
}

static int
zpl_rmdir(struct inode * dir, struct dentry *dentry)
{
	cred_t *cr = CRED();
	int error;
	fstrans_cookie_t cookie;

	crhold(cr);
	cookie = spl_fstrans_mark();
	error = -zfs_rmdir(dir, dname(dentry), NULL, cr, 0);
	spl_fstrans_unmark(cookie);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
zpl_commit_metadata(struct inode *inode)
{
	cred_t *cr = CRED();
	fstrans_cookie_t cookie;
	int error;

	crhold(cr);
	cookie = spl_fstrans_mark();
	error = -zfs_fsync(inode, 0, cr);
	spl_fstrans_unmark(cookie);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

/*
 * Linux 2.6.x - 2.6.34 API,
 * Through 2.6.34 the nfsd kernel server would pass a NULL 'file struct *'
 * to the fops->fsync() hook.  For this reason, we must be careful not to
 * use filp unconditionally.
 */
static int
zpl_fsync(struct file *filp, struct dentry *dentry, int datasync)
{
	cred_t *cr = CRED();
	int error;
	fstrans_cookie_t cookie;

	crhold(cr);
	cookie = spl_fstrans_mark();
	error = -zfs_fsync(dentry->d_inode, datasync, cr);
	spl_fstrans_unmark(cookie);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
zpl_iterate(struct file *filp, struct dir_context *ctx)
{
	cred_t *cr = CRED();
	int error;
	fstrans_cookie_t cookie;

	crhold(cr);
	cookie = spl_fstrans_mark();
	error = -zfs_readdir(file_inode(filp), ctx, cr);
	spl_fstrans_unmark(cookie);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static struct dentry *afs_export_get_dentry(struct super_block *sb,
					    void *inump)
{
    struct dentry *dp;
    cred_t *credp;

    credp = crref();
    AFS_GLOCK();

    dp = get_dentry_from_fid(credp, inump);

    AFS_GUNLOCK();
    crfree(credp);

    return dp;
}

static int
zpl_xattr_set(struct inode *ip, const char *name, const void *value,
    size_t size, int flags)
{
	znode_t *zp = ITOZ(ip);
	zfs_sb_t *zsb = ZTOZSB(zp);
	cred_t *cr = CRED();
	int error;

	crhold(cr);
	rw_enter(&ITOZ(ip)->z_xattr_lock, RW_WRITER);

	/*
	 * Before setting the xattr check to see if it already exists.
	 * This is done to ensure the following optional flags are honored.
	 *
	 *   XATTR_CREATE: fail if xattr already exists
	 *   XATTR_REPLACE: fail if xattr does not exist
	 */
	error = __zpl_xattr_get(ip, name, NULL, 0, cr);
	if (error < 0) {
		if (error != -ENODATA)
			goto out;

		if ((error == -ENODATA) && (flags & XATTR_REPLACE))
			goto out;
	} else {
		error = -EEXIST;
		if (flags & XATTR_CREATE)
			goto out;
	}

	/* Preferentially store the xattr as a SA for better performance */
	if (zsb->z_use_sa && zsb->z_xattr_sa && zp->z_is_sa) {
		error = zpl_xattr_set_sa(ip, name, value, size, flags, cr);
		if (error == 0)
			goto out;
	}

	error = zpl_xattr_set_dir(ip, name, value, size, flags, cr);
out:
	rw_exit(&ITOZ(ip)->z_xattr_lock);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

/* afs_root - stat the root of the file system. AFS global held on entry. */
static int
afs_root(struct super_block *afsp)
{
    afs_int32 code = 0;
    struct vrequest treq;
    struct vcache *tvp = 0;

    AFS_STATCNT(afs_root);
    if (afs_globalVp && (afs_globalVp->f.states & CStatd)) {
	tvp = afs_globalVp;
    } else {
	cred_t *credp = crref();

	if (afs_globalVp) {
	    afs_PutVCache(afs_globalVp);
	    afs_globalVp = NULL;
	}

	if (!(code = afs_InitReq(&treq, credp)) && !(code = afs_CheckInit())) {
	    tvp = afs_GetVCache(&afs_rootFid, &treq, NULL, NULL);
	    if (tvp) {
		struct inode *ip = AFSTOV(tvp);
		struct vattr vattr;

		afs_getattr(tvp, &vattr, credp);
		afs_fill_inode(ip, &vattr);

		/* setup super_block and mount point inode. */
		afs_globalVp = tvp;
#if defined(HAVE_LINUX_D_MAKE_ROOT)
		afsp->s_root = d_make_root(ip);
#else
		afsp->s_root = d_alloc_root(ip);
#endif
#if !defined(STRUCT_SUPER_BLOCK_HAS_S_D_OP)
		afsp->s_root->d_op = &afs_dentry_operations;
#endif
	    } else
		code = ENOENT;
	}
	crfree(credp);
    }

    afs_Trace2(afs_iclSetp, CM_TRACE_VFSROOT, ICL_TYPE_POINTER, afs_globalVp,
	       ICL_TYPE_INT32, code);
    return code;
}

static struct dentry *
zpl_get_parent(struct dentry *child)
{
	cred_t *cr = CRED();
	struct inode *ip;
	int error;

	crhold(cr);
	error = -zfs_lookup(child->d_inode, "..", &ip, 0, cr, NULL, NULL);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	if (error)
		return ERR_PTR(error);

	return zpl_dentry_obtain_alias(ip);
}