fs/gfs2/acl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   4  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   5  */
   6
   7 #include <linux/sched.h>
   8 #include <linux/slab.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/completion.h>
  11 #include <linux/buffer_head.h>
  12 #include <linux/xattr.h>
  13 #include <linux/posix_acl.h>
  14 #include <linux/posix_acl_xattr.h>
  15 #include <linux/gfs2_ondisk.h>
  16
  17 #include "gfs2.h"
  18 #include "incore.h"
  19 #include "acl.h"
  20 #include "xattr.h"
  21 #include "glock.h"
  22 #include "inode.h"
  23 #include "meta_io.h"
  24 #include "quota.h"
  25 #include "rgrp.h"
  26 #include "trans.h"
  27 #include "util.h"
  28
  29 static const char *gfs2_acl_name(int type)
  30 {
  31         switch (type) {
  32         case ACL_TYPE_ACCESS:
  33                 return XATTR_POSIX_ACL_ACCESS;
  34         case ACL_TYPE_DEFAULT:
  35                 return XATTR_POSIX_ACL_DEFAULT;
  36         }
  37         return NULL;
  38 }
  39
  40 static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
  41 {
  42         struct gfs2_inode *ip = GFS2_I(inode);
  43         struct posix_acl *acl;
  44         const char *name;
  45         char *data;
  46         int len;
  47
  48         if (!ip->i_eattr)
  49                 return NULL;
  50
  51         name = gfs2_acl_name(type);
  52         len = gfs2_xattr_acl_get(ip, name, &data);
  53         if (len <= 0)
  54                 return ERR_PTR(len);
  55         acl = posix_acl_from_xattr(&init_user_ns, data, len);
  56         kfree(data);
  57         return acl;
  58 }
  59
  60 struct posix_acl *gfs2_get_acl(struct inode *inode, int type, bool rcu)
  61 {
  62         struct gfs2_inode *ip = GFS2_I(inode);
  63         struct gfs2_holder gh;
  64         bool need_unlock = false;
  65         struct posix_acl *acl;
  66
  67         if (rcu)
  68                 return ERR_PTR(-ECHILD);
  69
  70         if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
  71                 int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
  72                                              LM_FLAG_ANY, &gh);
  73                 if (ret)
  74                         return ERR_PTR(ret);
  75                 need_unlock = true;
  76         }
  77         acl = __gfs2_get_acl(inode, type);
  78         if (need_unlock)
  79                 gfs2_glock_dq_uninit(&gh);
  80         return acl;
  81 }
  82
  83 int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  84 {
  85         int error;
  86         size_t len;
  87         char *data;
  88         const char *name = gfs2_acl_name(type);
  89
  90         if (acl) {
  91                 len = posix_acl_xattr_size(acl->a_count);
  92                 data = kmalloc(len, GFP_NOFS);
  93                 if (data == NULL)
  94                         return -ENOMEM;
  95                 error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
  96                 if (error < 0)
  97                         goto out;
  98         } else {
  99                 data = NULL;
 100                 len = 0;
 101         }
 102
 103         error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
 104         if (error)
 105                 goto out;
 106         set_cached_acl(inode, type, acl);
 107 out:
 108         kfree(data);
 109         return error;
 110 }
 111
 112 int gfs2_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 113                  struct posix_acl *acl, int type)
 114 {
 115         struct gfs2_inode *ip = GFS2_I(inode);
 116         struct gfs2_holder gh;
 117         bool need_unlock = false;
 118         int ret;
 119         umode_t mode;
 120
 121         if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
 122                 return -E2BIG;
 123
 124         ret = gfs2_qa_get(ip);
 125         if (ret)
 126                 return ret;
 127
 128         if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
 129                 ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
 130                 if (ret)
 131                         goto out;
 132                 need_unlock = true;
 133         }
 134
 135         mode = inode->i_mode;
 136         if (type == ACL_TYPE_ACCESS && acl) {
 137                 ret = posix_acl_update_mode(&init_user_ns, inode, &mode, &acl);
 138                 if (ret)
 139                         goto unlock;
 140         }
 141
 142         ret = __gfs2_set_acl(inode, acl, type);
 143         if (!ret && mode != inode->i_mode) {
 144                 inode->i_ctime = current_time(inode);
 145                 inode->i_mode = mode;
 146                 mark_inode_dirty(inode);
 147         }
 148 unlock:
 149         if (need_unlock)
 150                 gfs2_glock_dq_uninit(&gh);
 151 out:
 152         gfs2_qa_put(ip);
 153         return ret;
 154 }