fs/ceph/acl.c

   1 /*
   2  * linux/fs/ceph/acl.c
   3  *
   4  * Copyright (C) 2013 Guangliang Zhao, <lucienchao@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public
   8  * License v2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public
  16  * License along with this program; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18  * Boston, MA 021110-1307, USA.
  19  */
  20
  21 #include <linux/ceph/ceph_debug.h>
  22 #include <linux/fs.h>
  23 #include <linux/string.h>
  24 #include <linux/xattr.h>
  25 #include <linux/posix_acl_xattr.h>
  26 #include <linux/posix_acl.h>
  27 #include <linux/sched.h>
  28 #include <linux/slab.h>
  29
  30 #include "super.h"
  31
  32 static inline void ceph_set_cached_acl(struct inode *inode,
  33                                         int type, struct posix_acl *acl)
  34 {
  35         struct ceph_inode_info *ci = ceph_inode(inode);
  36
  37         spin_lock(&ci->i_ceph_lock);
  38         if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0))
  39                 set_cached_acl(inode, type, acl);
  40         spin_unlock(&ci->i_ceph_lock);
  41 }
  42
  43 static inline struct posix_acl *ceph_get_cached_acl(struct inode *inode,
  44                                                         int type)
  45 {
  46         struct ceph_inode_info *ci = ceph_inode(inode);
  47         struct posix_acl *acl = ACL_NOT_CACHED;
  48
  49         spin_lock(&ci->i_ceph_lock);
  50         if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0))
  51                 acl = get_cached_acl(inode, type);
  52         spin_unlock(&ci->i_ceph_lock);
  53
  54         return acl;
  55 }
  56
  57 struct posix_acl *ceph_get_acl(struct inode *inode, int type)
  58 {
  59         int size;
  60         const char *name;
  61         char *value = NULL;
  62         struct posix_acl *acl;
  63
  64         switch (type) {
  65         case ACL_TYPE_ACCESS:
  66                 name = POSIX_ACL_XATTR_ACCESS;
  67                 break;
  68         case ACL_TYPE_DEFAULT:
  69                 name = POSIX_ACL_XATTR_DEFAULT;
  70                 break;
  71         default:
  72                 BUG();
  73         }
  74
  75         size = __ceph_getxattr(inode, name, "", 0);
  76         if (size > 0) {
  77                 value = kzalloc(size, GFP_NOFS);
  78                 if (!value)
  79                         return ERR_PTR(-ENOMEM);
  80                 size = __ceph_getxattr(inode, name, value, size);
  81         }
  82
  83         if (size > 0)
  84                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
  85         else if (size == -ERANGE || size == -ENODATA || size == 0)
  86                 acl = NULL;
  87         else
  88                 acl = ERR_PTR(-EIO);
  89
  90         kfree(value);
  91
  92         if (!IS_ERR(acl))
  93                 ceph_set_cached_acl(inode, type, acl);
  94
  95         return acl;
  96 }
  97
  98 int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  99 {
 100         int ret = 0, size = 0;
 101         const char *name = NULL;
 102         char *value = NULL;
 103         struct iattr newattrs;
 104         umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
 105         struct dentry *dentry;
 106
 107         switch (type) {
 108         case ACL_TYPE_ACCESS:
 109                 name = POSIX_ACL_XATTR_ACCESS;
 110                 if (acl) {
 111                         ret = posix_acl_equiv_mode(acl, &new_mode);
 112                         if (ret < 0)
 113                                 goto out;
 114                         if (ret == 0)
 115                                 acl = NULL;
 116                 }
 117                 break;
 118         case ACL_TYPE_DEFAULT:
 119                 if (!S_ISDIR(inode->i_mode)) {
 120                         ret = acl ? -EINVAL : 0;
 121                         goto out;
 122                 }
 123                 name = POSIX_ACL_XATTR_DEFAULT;
 124                 break;
 125         default:
 126                 ret = -EINVAL;
 127                 goto out;
 128         }
 129
 130         if (acl) {
 131                 size = posix_acl_xattr_size(acl->a_count);
 132                 value = kmalloc(size, GFP_NOFS);
 133                 if (!value) {
 134                         ret = -ENOMEM;
 135                         goto out;
 136                 }
 137
 138                 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 139                 if (ret < 0)
 140                         goto out_free;
 141         }
 142
 143         dentry = d_find_alias(inode);
 144         if (new_mode != old_mode) {
 145                 newattrs.ia_mode = new_mode;
 146                 newattrs.ia_valid = ATTR_MODE;
 147                 ret = ceph_setattr(dentry, &newattrs);
 148                 if (ret)
 149                         goto out_dput;
 150         }
 151
 152         ret = __ceph_setxattr(dentry, name, value, size, 0);
 153         if (ret) {
 154                 if (new_mode != old_mode) {
 155                         newattrs.ia_mode = old_mode;
 156                         newattrs.ia_valid = ATTR_MODE;
 157                         ceph_setattr(dentry, &newattrs);
 158                 }
 159                 goto out_dput;
 160         }
 161
 162         ceph_set_cached_acl(inode, type, acl);
 163
 164 out_dput:
 165         dput(dentry);
 166 out_free:
 167         kfree(value);
 168 out:
 169         return ret;
 170 }
 171
 172 int ceph_init_acl(struct dentry *dentry, struct inode *inode, struct inode *dir)
 173 {
 174         struct posix_acl *default_acl, *acl;
 175         int error;
 176
 177         error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 178         if (error)
 179                 return error;
 180
 181         if (!default_acl && !acl)
 182                 cache_no_acl(inode);
 183
 184         if (default_acl) {
 185                 error = ceph_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
 186                 posix_acl_release(default_acl);
 187         }
 188         if (acl) {
 189                 if (!error)
 190                         error = ceph_set_acl(inode, acl, ACL_TYPE_ACCESS);
 191                 posix_acl_release(acl);
 192         }
 193         return error;
 194 }