LXR linux/fs/gfs2/acl.c

   1/*
   2 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4 *
   5 * This copyrighted material is made available to anyone wishing to use,
   6 * modify, copy, or redistribute it subject to the terms and conditions
   7 * of the GNU General Public License version 2.
   8 */
   9
  10#include <linux/sched.h>
  11#include <linux/slab.h>
  12#include <linux/spinlock.h>
  13#include <linux/completion.h>
  14#include <linux/buffer_head.h>
  15#include <linux/xattr.h>
  16#include <linux/posix_acl.h>
  17#include <linux/posix_acl_xattr.h>
  18#include <linux/gfs2_ondisk.h>
  19
  20#include "gfs2.h"
  21#include "incore.h"
  22#include "acl.h"
  23#include "xattr.h"
  24#include "glock.h"
  25#include "inode.h"
  26#include "meta_io.h"
  27#include "rgrp.h"
  28#include "trans.h"
  29#include "util.h"
  30
  31static const char *gfs2_acl_name(int type)
  32{
  33        switch (type) {
  34        case ACL_TYPE_ACCESS:
  35                return XATTR_POSIX_ACL_ACCESS;
  36        case ACL_TYPE_DEFAULT:
  37                return XATTR_POSIX_ACL_DEFAULT;
  38        }
  39        return NULL;
  40}
  41
  42static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
  43{
  44        struct gfs2_inode *ip = GFS2_I(inode);
  45        struct posix_acl *acl;
  46        const char *name;
  47        char *data;
  48        int len;
  49
  50        if (!ip->i_eattr)
  51                return NULL;
  52
  53        name = gfs2_acl_name(type);
  54        len = gfs2_xattr_acl_get(ip, name, &data);
  55        if (len <= 0)
  56                return ERR_PTR(len);
  57        acl = posix_acl_from_xattr(&init_user_ns, data, len);
  58        kfree(data);
  59        return acl;
  60}
  61
  62struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
  63{
  64        struct gfs2_inode *ip = GFS2_I(inode);
  65        struct gfs2_holder gh;
  66        bool need_unlock = false;
  67        struct posix_acl *acl;
  68
  69        if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
  70                int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
  71                                             LM_FLAG_ANY, &gh);
  72                if (ret)
  73                        return ERR_PTR(ret);
  74                need_unlock = true;
  75        }
  76        acl = __gfs2_get_acl(inode, type);
  77        if (need_unlock)
  78                gfs2_glock_dq_uninit(&gh);
  79        return acl;
  80}
  81
  82int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  83{
  84        int error;
  85        int len;
  86        char *data;
  87        const char *name = gfs2_acl_name(type);
  88
  89        if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
  90                return -E2BIG;
  91
  92        if (type == ACL_TYPE_ACCESS) {
  93                umode_t mode = inode->i_mode;
  94
  95                error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
  96                if (error)
  97                        return error;
  98                if (mode != inode->i_mode)
  99                        mark_inode_dirty(inode);
 100        }
 101
 102        if (acl) {
 103                len = posix_acl_to_xattr(&init_user_ns, acl, NULL, 0);
 104                if (len == 0)
 105                        return 0;
 106                data = kmalloc(len, GFP_NOFS);
 107                if (data == NULL)
 108                        return -ENOMEM;
 109                error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
 110                if (error < 0)
 111                        goto out;
 112        } else {
 113                data = NULL;
 114                len = 0;
 115        }
 116
 117        error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
 118        if (error)
 119                goto out;
 120        set_cached_acl(inode, type, acl);
 121out:
 122        kfree(data);
 123        return error;
 124}
 125
 126int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 127{
 128        struct gfs2_inode *ip = GFS2_I(inode);
 129        struct gfs2_holder gh;
 130        bool need_unlock = false;
 131        int ret;
 132
 133        ret = gfs2_rsqa_alloc(ip);
 134        if (ret)
 135                return ret;
 136
 137        if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
 138                ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
 139                if (ret)
 140                        return ret;
 141                need_unlock = true;
 142        }
 143        ret = __gfs2_set_acl(inode, acl, type);
 144        if (need_unlock)
 145                gfs2_glock_dq_uninit(&gh);
 146        return ret;
 147}
 148