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         else
  41                 forget_cached_acl(inode, type);
  42         spin_unlock(&ci->i_ceph_lock);
  43 }
  44
  45 struct posix_acl *ceph_get_acl(struct inode *inode, int type)
  46 {
  47         int size;
  48         const char *name;
  49         char *value = NULL;
  50         struct posix_acl *acl;
  51
  52         switch (type) {
  53         case ACL_TYPE_ACCESS:
  54                 name = XATTR_NAME_POSIX_ACL_ACCESS;
  55                 break;
  56         case ACL_TYPE_DEFAULT:
  57                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
  58                 break;
  59         default:
  60                 BUG();
  61         }
  62
  63         size = __ceph_getxattr(inode, name, "", 0);
  64         if (size > 0) {
  65                 value = kzalloc(size, GFP_NOFS);
  66                 if (!value)
  67                         return ERR_PTR(-ENOMEM);
  68                 size = __ceph_getxattr(inode, name, value, size);
  69         }
  70
  71         if (size > 0)
  72                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
  73         else if (size == -ERANGE || size == -ENODATA || size == 0)
  74                 acl = NULL;
  75         else
  76                 acl = ERR_PTR(-EIO);
  77
  78         kfree(value);
  79
  80         if (!IS_ERR(acl))
  81                 ceph_set_cached_acl(inode, type, acl);
  82
  83         return acl;
  84 }
  85
  86 int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  87 {
  88         int ret = 0, size = 0;
  89         const char *name = NULL;
  90         char *value = NULL;
  91         struct iattr newattrs;
  92         umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
  93
  94         switch (type) {
  95         case ACL_TYPE_ACCESS:
  96                 name = XATTR_NAME_POSIX_ACL_ACCESS;
  97                 if (acl) {
  98                         ret = posix_acl_update_mode(inode, &new_mode, &acl);
  99                         if (ret)
 100                                 goto out;
 101                 }
 102                 break;
 103         case ACL_TYPE_DEFAULT:
 104                 if (!S_ISDIR(inode->i_mode)) {
 105                         ret = acl ? -EINVAL : 0;
 106                         goto out;
 107                 }
 108                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 109                 break;
 110         default:
 111                 ret = -EINVAL;
 112                 goto out;
 113         }
 114
 115         if (acl) {
 116                 size = posix_acl_xattr_size(acl->a_count);
 117                 value = kmalloc(size, GFP_NOFS);
 118                 if (!value) {
 119                         ret = -ENOMEM;
 120                         goto out;
 121                 }
 122
 123                 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 124                 if (ret < 0)
 125                         goto out_free;
 126         }
 127
 128         if (ceph_snap(inode) != CEPH_NOSNAP) {
 129                 ret = -EROFS;
 130                 goto out_free;
 131         }
 132
 133         if (new_mode != old_mode) {
 134                 newattrs.ia_mode = new_mode;
 135                 newattrs.ia_valid = ATTR_MODE;
 136                 ret = __ceph_setattr(inode, &newattrs);
 137                 if (ret)
 138                         goto out_free;
 139         }
 140
 141         ret = __ceph_setxattr(inode, name, value, size, 0);
 142         if (ret) {
 143                 if (new_mode != old_mode) {
 144                         newattrs.ia_mode = old_mode;
 145                         newattrs.ia_valid = ATTR_MODE;
 146                         __ceph_setattr(inode, &newattrs);
 147                 }
 148                 goto out_free;
 149         }
 150
 151         ceph_set_cached_acl(inode, type, acl);
 152
 153 out_free:
 154         kfree(value);
 155 out:
 156         return ret;
 157 }
 158
 159 int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
 160                        struct ceph_acls_info *info)
 161 {
 162         struct posix_acl *acl, *default_acl;
 163         size_t val_size1 = 0, val_size2 = 0;
 164         struct ceph_pagelist *pagelist = NULL;
 165         void *tmp_buf = NULL;
 166         int err;
 167
 168         err = posix_acl_create(dir, mode, &default_acl, &acl);
 169         if (err)
 170                 return err;
 171
 172         if (acl) {
 173                 int ret = posix_acl_equiv_mode(acl, mode);
 174                 if (ret < 0)
 175                         goto out_err;
 176                 if (ret == 0) {
 177                         posix_acl_release(acl);
 178                         acl = NULL;
 179                 }
 180         }
 181
 182         if (!default_acl && !acl)
 183                 return 0;
 184
 185         if (acl)
 186                 val_size1 = posix_acl_xattr_size(acl->a_count);
 187         if (default_acl)
 188                 val_size2 = posix_acl_xattr_size(default_acl->a_count);
 189
 190         err = -ENOMEM;
 191         tmp_buf = kmalloc(max(val_size1, val_size2), GFP_KERNEL);
 192         if (!tmp_buf)
 193                 goto out_err;
 194         pagelist = kmalloc(sizeof(struct ceph_pagelist), GFP_KERNEL);
 195         if (!pagelist)
 196                 goto out_err;
 197         ceph_pagelist_init(pagelist);
 198
 199         err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
 200         if (err)
 201                 goto out_err;
 202
 203         ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
 204
 205         if (acl) {
 206                 size_t len = strlen(XATTR_NAME_POSIX_ACL_ACCESS);
 207                 err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
 208                 if (err)
 209                         goto out_err;
 210                 ceph_pagelist_encode_string(pagelist, XATTR_NAME_POSIX_ACL_ACCESS,
 211                                             len);
 212                 err = posix_acl_to_xattr(&init_user_ns, acl,
 213                                          tmp_buf, val_size1);
 214                 if (err < 0)
 215                         goto out_err;
 216                 ceph_pagelist_encode_32(pagelist, val_size1);
 217                 ceph_pagelist_append(pagelist, tmp_buf, val_size1);
 218         }
 219         if (default_acl) {
 220                 size_t len = strlen(XATTR_NAME_POSIX_ACL_DEFAULT);
 221                 err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
 222                 if (err)
 223                         goto out_err;
 224                 err = ceph_pagelist_encode_string(pagelist,
 225                                                   XATTR_NAME_POSIX_ACL_DEFAULT, len);
 226                 err = posix_acl_to_xattr(&init_user_ns, default_acl,
 227                                          tmp_buf, val_size2);
 228                 if (err < 0)
 229                         goto out_err;
 230                 ceph_pagelist_encode_32(pagelist, val_size2);
 231                 ceph_pagelist_append(pagelist, tmp_buf, val_size2);
 232         }
 233
 234         kfree(tmp_buf);
 235
 236         info->acl = acl;
 237         info->default_acl = default_acl;
 238         info->pagelist = pagelist;
 239         return 0;
 240
 241 out_err:
 242         posix_acl_release(acl);
 243         posix_acl_release(default_acl);
 244         kfree(tmp_buf);
 245         if (pagelist)
 246                 ceph_pagelist_release(pagelist);
 247         return err;
 248 }
 249
 250 void ceph_init_inode_acls(struct inode* inode, struct ceph_acls_info *info)
 251 {
 252         if (!inode)
 253                 return;
 254         ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, info->acl);
 255         ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, info->default_acl);
 256 }
 257
 258 void ceph_release_acls_info(struct ceph_acls_info *info)
 259 {
 260         posix_acl_release(info->acl);
 261         posix_acl_release(info->default_acl);
 262         if (info->pagelist)
 263                 ceph_pagelist_release(info->pagelist);
 264 }