1 files changed, 351 insertions, 0 deletions

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
new file mode 100644
index 000000000000..1d53b62dbba5
--- /dev/null
+++ b/fs/btrfs/acl.c
@@ -0,0 +1,351 @@
+/*
+ * Copyright (C) 2007 Red Hat.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/posix_acl.h>
+#include <linux/sched.h>
+
+#include "ctree.h"
+#include "btrfs_inode.h"
+#include "xattr.h"
+
+#ifdef CONFIG_FS_POSIX_ACL
+
+static void btrfs_update_cached_acl(struct inode *inode,
+                                    struct posix_acl **p_acl,
+                                    struct posix_acl *acl)
+{
+        spin_lock(&inode->i_lock);
+        if (*p_acl && *p_acl != BTRFS_ACL_NOT_CACHED)
+                posix_acl_release(*p_acl);
+        *p_acl = posix_acl_dup(acl);
+        spin_unlock(&inode->i_lock);
+}
+
+static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
+{
+        int size;
+        const char *name;
+        char *value = NULL;
+        struct posix_acl *acl = NULL, **p_acl;
+
+        switch (type) {
+        case ACL_TYPE_ACCESS:
+                name = POSIX_ACL_XATTR_ACCESS;
+                p_acl = &BTRFS_I(inode)->i_acl;
+                break;
+        case ACL_TYPE_DEFAULT:
+                name = POSIX_ACL_XATTR_DEFAULT;
+                p_acl = &BTRFS_I(inode)->i_default_acl;
+                break;
+        default:
+                return ERR_PTR(-EINVAL);
+        }
+
+        spin_lock(&inode->i_lock);
+        if (*p_acl != BTRFS_ACL_NOT_CACHED)
+                acl = posix_acl_dup(*p_acl);
+        spin_unlock(&inode->i_lock);
+
+        if (acl)
+                return acl;
+
+
+        size = __btrfs_getxattr(inode, name, "", 0);
+        if (size > 0) {
+                value = kzalloc(size, GFP_NOFS);
+                if (!value)
+                        return ERR_PTR(-ENOMEM);
+                size = __btrfs_getxattr(inode, name, value, size);
+                if (size > 0) {
+                        acl = posix_acl_from_xattr(value, size);
+                        btrfs_update_cached_acl(inode, p_acl, acl);
+                }
+                kfree(value);
+        } else if (size == -ENOENT) {
+                acl = NULL;
+                btrfs_update_cached_acl(inode, p_acl, acl);
+        }
+
+        return acl;
+}
+
+static int btrfs_xattr_get_acl(struct inode *inode, int type,
+                               void *value, size_t size)
+{
+        struct posix_acl *acl;
+        int ret = 0;
+
+        acl = btrfs_get_acl(inode, type);
+
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        if (acl == NULL)
+                return -ENODATA;
+        ret = posix_acl_to_xattr(acl, value, size);
+        posix_acl_release(acl);
+
+        return ret;
+}
+
+/*
+ * Needs to be called with fs_mutex held
+ */
+static int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+        int ret, size = 0;
+        const char *name;
+        struct posix_acl **p_acl;
+        char *value = NULL;
+        mode_t mode;
+
+        if (acl) {
+                ret = posix_acl_valid(acl);
+                if (ret < 0)
+                        return ret;
+                ret = 0;
+        }
+
+        switch (type) {
+        case ACL_TYPE_ACCESS:
+                mode = inode->i_mode;
+                ret = posix_acl_equiv_mode(acl, &mode);
+                if (ret < 0)
+                        return ret;
+                ret = 0;
+                inode->i_mode = mode;
+                name = POSIX_ACL_XATTR_ACCESS;
+                p_acl = &BTRFS_I(inode)->i_acl;
+                break;
+        case ACL_TYPE_DEFAULT:
+                if (!S_ISDIR(inode->i_mode))
+                        return acl ? -EINVAL : 0;
+                name = POSIX_ACL_XATTR_DEFAULT;
+                p_acl = &BTRFS_I(inode)->i_default_acl;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        if (acl) {
+                size = posix_acl_xattr_size(acl->a_count);
+                value = kmalloc(size, GFP_NOFS);
+                if (!value) {
+                        ret = -ENOMEM;
+                        goto out;
+                }
+
+                ret = posix_acl_to_xattr(acl, value, size);
+                if (ret < 0)
+                        goto out;
+        }
+
+        ret = __btrfs_setxattr(inode, name, value, size, 0);
+
+out:
+        kfree(value);
+
+        if (!ret)
+                btrfs_update_cached_acl(inode, p_acl, acl);
+
+        return ret;
+}
+
+static int btrfs_xattr_set_acl(struct inode *inode, int type,
+                               const void *value, size_t size)
+{
+        int ret = 0;
+        struct posix_acl *acl = NULL;
+
+        if (value) {
+                acl = posix_acl_from_xattr(value, size);
+                if (acl == NULL) {
+                        value = NULL;
+                        size = 0;
+                } else if (IS_ERR(acl)) {
+                        return PTR_ERR(acl);
+                }
+        }
+
+        ret = btrfs_set_acl(inode, acl, type);
+
+        posix_acl_release(acl);
+
+        return ret;
+}
+
+
+static int btrfs_xattr_acl_access_get(struct inode *inode, const char *name,
+                                      void *value, size_t size)
+{
+        return btrfs_xattr_get_acl(inode, ACL_TYPE_ACCESS, value, size);
+}
+
+static int btrfs_xattr_acl_access_set(struct inode *inode, const char *name,
+                                      const void *value, size_t size, int flags)
+{
+        return btrfs_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
+}
+
+static int btrfs_xattr_acl_default_get(struct inode *inode, const char *name,
+                                       void *value, size_t size)
+{
+        return btrfs_xattr_get_acl(inode, ACL_TYPE_DEFAULT, value, size);
+}
+
+static int btrfs_xattr_acl_default_set(struct inode *inode, const char *name,
+                               const void *value, size_t size, int flags)
+{
+        return btrfs_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
+}
+
+int btrfs_check_acl(struct inode *inode, int mask)
+{
+        struct posix_acl *acl;
+        int error = -EAGAIN;
+
+        acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        if (acl) {
+                error = posix_acl_permission(inode, acl, mask);
+                posix_acl_release(acl);
+        }
+
+        return error;
+}
+
+/*
+ * btrfs_init_acl is already generally called under fs_mutex, so the locking
+ * stuff has been fixed to work with that.  If the locking stuff changes, we
+ * need to re-evaluate the acl locking stuff.
+ */
+int btrfs_init_acl(struct inode *inode, struct inode *dir)
+{
+        struct posix_acl *acl = NULL;
+        int ret = 0;
+
+        /* this happens with subvols */
+        if (!dir)
+                return 0;
+
+        if (!S_ISLNK(inode->i_mode)) {
+                if (IS_POSIXACL(dir)) {
+                        acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
+                        if (IS_ERR(acl))
+                                return PTR_ERR(acl);
+                }
+
+                if (!acl)
+                        inode->i_mode &= ~current->fs->umask;
+        }
+
+        if (IS_POSIXACL(dir) && acl) {
+                struct posix_acl *clone;
+                mode_t mode;
+
+                if (S_ISDIR(inode->i_mode)) {
+                        ret = btrfs_set_acl(inode, acl, ACL_TYPE_DEFAULT);
+                        if (ret)
+                                goto failed;
+                }
+                clone = posix_acl_clone(acl, GFP_NOFS);
+                ret = -ENOMEM;
+                if (!clone)
+                        goto failed;
+
+                mode = inode->i_mode;
+                ret = posix_acl_create_masq(clone, &mode);
+                if (ret >= 0) {
+                        inode->i_mode = mode;
+                        if (ret > 0) {
+                                /* we need an acl */
+                                ret = btrfs_set_acl(inode, clone,
+                                                    ACL_TYPE_ACCESS);
+                        }
+                }
+        }
+failed:
+        posix_acl_release(acl);
+
+        return ret;
+}
+
+int btrfs_acl_chmod(struct inode *inode)
+{
+        struct posix_acl *acl, *clone;
+        int ret = 0;
+
+        if (S_ISLNK(inode->i_mode))
+                return -EOPNOTSUPP;
+
+        if (!IS_POSIXACL(inode))
+                return 0;
+
+        acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+        if (IS_ERR(acl) || !acl)
+                return PTR_ERR(acl);
+
+        clone = posix_acl_clone(acl, GFP_KERNEL);
+        posix_acl_release(acl);
+        if (!clone)
+                return -ENOMEM;
+
+        ret = posix_acl_chmod_masq(clone, inode->i_mode);
+        if (!ret)
+                ret = btrfs_set_acl(inode, clone, ACL_TYPE_ACCESS);
+
+        posix_acl_release(clone);
+
+        return ret;
+}
+
+struct xattr_handler btrfs_xattr_acl_default_handler = {
+        .prefix = POSIX_ACL_XATTR_DEFAULT,
+        .get    = btrfs_xattr_acl_default_get,
+        .set    = btrfs_xattr_acl_default_set,
+};
+
+struct xattr_handler btrfs_xattr_acl_access_handler = {
+        .prefix = POSIX_ACL_XATTR_ACCESS,
+        .get    = btrfs_xattr_acl_access_get,
+        .set    = btrfs_xattr_acl_access_set,
+};
+
+#else /* CONFIG_FS_POSIX_ACL */
+
+int btrfs_acl_chmod(struct inode *inode)
+{
+        return 0;
+}
+
+int btrfs_init_acl(struct inode *inode, struct inode *dir)
+{
+        return 0;
+}
+
+int btrfs_check_acl(struct inode *inode, int mask)
+{
+        return 0;
+}
+
+#endif /* CONFIG_FS_POSIX_ACL */