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 "trans.h"
  28 #include "util.h"
  29
  30 static const char *gfs2_acl_name(int type)
  31 {
  32         switch (type) {
  33         case ACL_TYPE_ACCESS:
  34                 return GFS2_POSIX_ACL_ACCESS;
  35         case ACL_TYPE_DEFAULT:
  36                 return GFS2_POSIX_ACL_DEFAULT;
  37         }
  38         return NULL;
  39 }
  40
  41 struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
  42 {
  43         struct gfs2_inode *ip = GFS2_I(inode);
  44         struct posix_acl *acl;
  45         const char *name;
  46         char *data;
  47         int len;
  48
  49         if (!ip->i_eattr)
  50                 return NULL;
  51
  52         name = gfs2_acl_name(type);
  53         if (name == NULL)
  54                 return ERR_PTR(-EINVAL);
  55
  56         len = gfs2_xattr_acl_get(ip, name, &data);
  57         if (len < 0)
  58                 return ERR_PTR(len);
  59         if (len == 0)
  60                 return NULL;
  61
  62         acl = posix_acl_from_xattr(&init_user_ns, data, len);
  63         kfree(data);
  64         return acl;
  65 }
  66
  67 static int gfs2_set_mode(struct inode *inode, umode_t mode)
  68 {
  69         int error = 0;
  70
  71         if (mode != inode->i_mode) {
  72                 inode->i_mode = mode;
  73                 mark_inode_dirty(inode);
  74         }
  75
  76         return error;
  77 }
  78
  79 int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  80 {
  81         int error;
  82         int len;
  83         char *data;
  84         const char *name = gfs2_acl_name(type);
  85
  86         BUG_ON(name == NULL);
  87
  88         if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
  89                 return -EINVAL;
  90
  91         if (type == ACL_TYPE_ACCESS) {
  92                 umode_t mode = inode->i_mode;
  93
  94                 error = posix_acl_equiv_mode(acl, &mode);
  95                 if (error < 0)
  96                         return error;
  97
  98                 if (error == 0)
  99                         acl = NULL;
 100
 101                 error = gfs2_set_mode(inode, mode);
 102                 if (error)
 103                         return error;
 104         }
 105
 106         if (acl) {
 107                 len = posix_acl_to_xattr(&init_user_ns, acl, NULL, 0);
 108                 if (len == 0)
 109                         return 0;
 110                 data = kmalloc(len, GFP_NOFS);
 111                 if (data == NULL)
 112                         return -ENOMEM;
 113                 error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
 114                 if (error < 0)
 115                         goto out;
 116         } else {
 117                 data = NULL;
 118                 len = 0;
 119         }
 120
 121         error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
 122         if (error)
 123                 goto out;
 124
 125         if (acl)
 126                 set_cached_acl(inode, type, acl);
 127         else
 128                 forget_cached_acl(inode, type);
 129 out:
 130         kfree(data);
 131         return error;
 132 }