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 void ceph_forget_all_cached_acls(struct inode *inode)
  58 {
  59         forget_all_cached_acls(inode);
  60 }
  61
  62 struct posix_acl *ceph_get_acl(struct inode *inode, int type)
  63 {
  64         int size;
  65         const char *name;
  66         char *value = NULL;
  67         struct posix_acl *acl;
  68
  69         if (!IS_POSIXACL(inode))
  70                 return NULL;
  71
  72         acl = ceph_get_cached_acl(inode, type);
  73         if (acl != ACL_NOT_CACHED)
  74                 return acl;
  75
  76         switch (type) {
  77         case ACL_TYPE_ACCESS:
  78                 name = POSIX_ACL_XATTR_ACCESS;
  79                 break;
  80         case ACL_TYPE_DEFAULT:
  81                 name = POSIX_ACL_XATTR_DEFAULT;
  82                 break;
  83         default:
  84                 BUG();
  85         }
  86
  87         size = __ceph_getxattr(inode, name, "", 0);
  88         if (size > 0) {
  89                 value = kzalloc(size, GFP_NOFS);
  90                 if (!value)
  91                         return ERR_PTR(-ENOMEM);
  92                 size = __ceph_getxattr(inode, name, value, size);
  93         }
  94
  95         if (size > 0)
  96                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
  97         else if (size == -ERANGE || size == -ENODATA || size == 0)
  98                 acl = NULL;
  99         else
 100                 acl = ERR_PTR(-EIO);
 101
 102         kfree(value);
 103
 104         if (!IS_ERR(acl))
 105                 ceph_set_cached_acl(inode, type, acl);
 106
 107         return acl;
 108 }
 109
 110 int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 111 {
 112         int ret = 0, size = 0;
 113         const char *name = NULL;
 114         char *value = NULL;
 115         struct iattr newattrs;
 116         umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
 117         struct dentry *dentry = d_find_alias(inode);
 118
 119         if (acl) {
 120                 ret = posix_acl_valid(acl);
 121                 if (ret < 0)
 122                         goto out;
 123         }
 124
 125         switch (type) {
 126         case ACL_TYPE_ACCESS:
 127                 name = POSIX_ACL_XATTR_ACCESS;
 128                 if (acl) {
 129                         ret = posix_acl_equiv_mode(acl, &new_mode);
 130                         if (ret < 0)
 131                                 goto out;
 132                         if (ret == 0)
 133                                 acl = NULL;
 134                 }
 135                 break;
 136         case ACL_TYPE_DEFAULT:
 137                 if (!S_ISDIR(inode->i_mode)) {
 138                         ret = acl ? -EINVAL : 0;
 139                         goto out;
 140                 }
 141                 name = POSIX_ACL_XATTR_DEFAULT;
 142                 break;
 143         default:
 144                 ret = -EINVAL;
 145                 goto out;
 146         }
 147
 148         if (acl) {
 149                 size = posix_acl_xattr_size(acl->a_count);
 150                 value = kmalloc(size, GFP_NOFS);
 151                 if (!value) {
 152                         ret = -ENOMEM;
 153                         goto out;
 154                 }
 155
 156                 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 157                 if (ret < 0)
 158                         goto out_free;
 159         }
 160
 161         if (new_mode != old_mode) {
 162                 newattrs.ia_mode = new_mode;
 163                 newattrs.ia_valid = ATTR_MODE;
 164                 ret = ceph_setattr(dentry, &newattrs);
 165                 if (ret)
 166                         goto out_free;
 167         }
 168
 169         if (value)
 170                 ret = __ceph_setxattr(dentry, name, value, size, 0);
 171         else
 172                 ret = __ceph_removexattr(dentry, name);
 173
 174         if (ret) {
 175                 if (new_mode != old_mode) {
 176                         newattrs.ia_mode = old_mode;
 177                         newattrs.ia_valid = ATTR_MODE;
 178                         ceph_setattr(dentry, &newattrs);
 179                 }
 180                 goto out_free;
 181         }
 182
 183         ceph_set_cached_acl(inode, type, acl);
 184
 185 out_free:
 186         kfree(value);
 187 out:
 188         return ret;
 189 }
 190
 191 int ceph_init_acl(struct dentry *dentry, struct inode *inode, struct inode *dir)
 192 {
 193         struct posix_acl *acl = NULL;
 194         int ret = 0;
 195
 196         if (!S_ISLNK(inode->i_mode)) {
 197                 if (IS_POSIXACL(dir)) {
 198                         acl = ceph_get_acl(dir, ACL_TYPE_DEFAULT);
 199                         if (IS_ERR(acl)) {
 200                                 ret = PTR_ERR(acl);
 201                                 goto out;
 202                         }
 203                 }
 204
 205                 if (!acl)
 206                         inode->i_mode &= ~current_umask();
 207         }
 208
 209         if (IS_POSIXACL(dir) && acl) {
 210                 if (S_ISDIR(inode->i_mode)) {
 211                         ret = ceph_set_acl(inode, acl, ACL_TYPE_DEFAULT);
 212                         if (ret)
 213                                 goto out_release;
 214                 }
 215                 ret = __posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
 216                 if (ret < 0)
 217                         goto out;
 218                 else if (ret > 0)
 219                         ret = ceph_set_acl(inode, acl, ACL_TYPE_ACCESS);
 220                 else
 221                         cache_no_acl(inode);
 222         } else {
 223                 cache_no_acl(inode);
 224         }
 225
 226 out_release:
 227         posix_acl_release(acl);
 228 out:
 229         return ret;
 230 }