| 1 | /* |
| 2 | * Copyright (C) 2007 Red Hat. All rights reserved. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public |
| 6 | * License v2 as published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 11 | * General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public |
| 14 | * License along with this program; if not, write to the |
| 15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 16 | * Boston, MA 021110-1307, USA. |
| 17 | */ |
| 18 | |
| 19 | #include <linux/fs.h> |
| 20 | #include <linux/string.h> |
| 21 | #include <linux/xattr.h> |
| 22 | #include <linux/posix_acl_xattr.h> |
| 23 | #include <linux/posix_acl.h> |
| 24 | #include <linux/sched.h> |
| 25 | #include <linux/slab.h> |
| 26 | |
| 27 | #include "ctree.h" |
| 28 | #include "btrfs_inode.h" |
| 29 | #include "xattr.h" |
| 30 | |
| 31 | struct posix_acl *btrfs_get_acl(struct inode *inode, int type) |
| 32 | { |
| 33 | int size; |
| 34 | const char *name; |
| 35 | char *value = NULL; |
| 36 | struct posix_acl *acl; |
| 37 | |
| 38 | switch (type) { |
| 39 | case ACL_TYPE_ACCESS: |
| 40 | name = POSIX_ACL_XATTR_ACCESS; |
| 41 | break; |
| 42 | case ACL_TYPE_DEFAULT: |
| 43 | name = POSIX_ACL_XATTR_DEFAULT; |
| 44 | break; |
| 45 | default: |
| 46 | BUG(); |
| 47 | } |
| 48 | |
| 49 | size = __btrfs_getxattr(inode, name, "", 0); |
| 50 | if (size > 0) { |
| 51 | value = kzalloc(size, GFP_NOFS); |
| 52 | if (!value) |
| 53 | return ERR_PTR(-ENOMEM); |
| 54 | size = __btrfs_getxattr(inode, name, value, size); |
| 55 | } |
| 56 | if (size > 0) { |
| 57 | acl = posix_acl_from_xattr(&init_user_ns, value, size); |
| 58 | } else if (size == -ENOENT || size == -ENODATA || size == 0) { |
| 59 | /* FIXME, who returns -ENOENT? I think nobody */ |
| 60 | acl = NULL; |
| 61 | } else { |
| 62 | acl = ERR_PTR(-EIO); |
| 63 | } |
| 64 | kfree(value); |
| 65 | |
| 66 | if (!IS_ERR(acl)) |
| 67 | set_cached_acl(inode, type, acl); |
| 68 | |
| 69 | return acl; |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * Needs to be called with fs_mutex held |
| 74 | */ |
| 75 | static int __btrfs_set_acl(struct btrfs_trans_handle *trans, |
| 76 | struct inode *inode, struct posix_acl *acl, int type) |
| 77 | { |
| 78 | int ret, size = 0; |
| 79 | const char *name; |
| 80 | char *value = NULL; |
| 81 | |
| 82 | if (acl) { |
| 83 | ret = posix_acl_valid(acl); |
| 84 | if (ret < 0) |
| 85 | return ret; |
| 86 | ret = 0; |
| 87 | } |
| 88 | |
| 89 | switch (type) { |
| 90 | case ACL_TYPE_ACCESS: |
| 91 | name = POSIX_ACL_XATTR_ACCESS; |
| 92 | if (acl) { |
| 93 | ret = posix_acl_equiv_mode(acl, &inode->i_mode); |
| 94 | if (ret < 0) |
| 95 | return ret; |
| 96 | if (ret == 0) |
| 97 | acl = NULL; |
| 98 | } |
| 99 | ret = 0; |
| 100 | break; |
| 101 | case ACL_TYPE_DEFAULT: |
| 102 | if (!S_ISDIR(inode->i_mode)) |
| 103 | return acl ? -EINVAL : 0; |
| 104 | name = POSIX_ACL_XATTR_DEFAULT; |
| 105 | break; |
| 106 | default: |
| 107 | return -EINVAL; |
| 108 | } |
| 109 | |
| 110 | if (acl) { |
| 111 | size = posix_acl_xattr_size(acl->a_count); |
| 112 | value = kmalloc(size, GFP_NOFS); |
| 113 | if (!value) { |
| 114 | ret = -ENOMEM; |
| 115 | goto out; |
| 116 | } |
| 117 | |
| 118 | ret = posix_acl_to_xattr(&init_user_ns, acl, value, size); |
| 119 | if (ret < 0) |
| 120 | goto out; |
| 121 | } |
| 122 | |
| 123 | ret = __btrfs_setxattr(trans, inode, name, value, size, 0); |
| 124 | out: |
| 125 | kfree(value); |
| 126 | |
| 127 | if (!ret) |
| 128 | set_cached_acl(inode, type, acl); |
| 129 | |
| 130 | return ret; |
| 131 | } |
| 132 | |
| 133 | int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) |
| 134 | { |
| 135 | return __btrfs_set_acl(NULL, inode, acl, type); |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | * btrfs_init_acl is already generally called under fs_mutex, so the locking |
| 140 | * stuff has been fixed to work with that. If the locking stuff changes, we |
| 141 | * need to re-evaluate the acl locking stuff. |
| 142 | */ |
| 143 | int btrfs_init_acl(struct btrfs_trans_handle *trans, |
| 144 | struct inode *inode, struct inode *dir) |
| 145 | { |
| 146 | struct posix_acl *default_acl, *acl; |
| 147 | int ret = 0; |
| 148 | |
| 149 | /* this happens with subvols */ |
| 150 | if (!dir) |
| 151 | return 0; |
| 152 | |
| 153 | ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); |
| 154 | if (ret) |
| 155 | return ret; |
| 156 | |
| 157 | if (default_acl) { |
| 158 | ret = __btrfs_set_acl(trans, inode, default_acl, |
| 159 | ACL_TYPE_DEFAULT); |
| 160 | posix_acl_release(default_acl); |
| 161 | } |
| 162 | |
| 163 | if (acl) { |
| 164 | if (!ret) |
| 165 | ret = __btrfs_set_acl(trans, inode, acl, |
| 166 | ACL_TYPE_ACCESS); |
| 167 | posix_acl_release(acl); |
| 168 | } |
| 169 | |
| 170 | if (!default_acl && !acl) |
| 171 | cache_no_acl(inode); |
| 172 | return ret; |
| 173 | } |