1 files changed, 322 insertions, 0 deletions

diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
new file mode 100644
index 000000000000..7f332e270894
--- /dev/null
+++ b/fs/btrfs/xattr.c
@@ -0,0 +1,322 @@
+/*
+ * 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/init.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/rwsem.h>
+#include <linux/xattr.h>
+#include "ctree.h"
+#include "btrfs_inode.h"
+#include "transaction.h"
+#include "xattr.h"
+#include "disk-io.h"
+
+
+ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
+                                void *buffer, size_t size)
+{
+        struct btrfs_dir_item *di;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct btrfs_path *path;
+        struct extent_buffer *leaf;
+        int ret = 0;
+        unsigned long data_ptr;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        /* lookup the xattr by name */
+        di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
+                                strlen(name), 0);
+        if (!di || IS_ERR(di)) {
+                ret = -ENODATA;
+                goto out;
+        }
+
+        leaf = path->nodes[0];
+        /* if size is 0, that means we want the size of the attr */
+        if (!size) {
+                ret = btrfs_dir_data_len(leaf, di);
+                goto out;
+        }
+
+        /* now get the data out of our dir_item */
+        if (btrfs_dir_data_len(leaf, di) > size) {
+                ret = -ERANGE;
+                goto out;
+        }
+        data_ptr = (unsigned long)((char *)(di + 1) +
+                                   btrfs_dir_name_len(leaf, di));
+        read_extent_buffer(leaf, buffer, data_ptr,
+                           btrfs_dir_data_len(leaf, di));
+        ret = btrfs_dir_data_len(leaf, di);
+
+out:
+        btrfs_free_path(path);
+        return ret;
+}
+
+int __btrfs_setxattr(struct inode *inode, const char *name,
+                            const void *value, size_t size, int flags)
+{
+        struct btrfs_dir_item *di;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct btrfs_trans_handle *trans;
+        struct btrfs_path *path;
+        int ret = 0, mod = 0;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        trans = btrfs_start_transaction(root, 1);
+        btrfs_set_trans_block_group(trans, inode);
+
+        /* first lets see if we already have this xattr */
+        di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
+                                strlen(name), -1);
+        if (IS_ERR(di)) {
+                ret = PTR_ERR(di);
+                goto out;
+        }
+
+        /* ok we already have this xattr, lets remove it */
+        if (di) {
+                /* if we want create only exit */
+                if (flags & XATTR_CREATE) {
+                        ret = -EEXIST;
+                        goto out;
+                }
+
+                ret = btrfs_delete_one_dir_name(trans, root, path, di);
+                if (ret)
+                        goto out;
+                btrfs_release_path(root, path);
+
+                /* if we don't have a value then we are removing the xattr */
+                if (!value) {
+                        mod = 1;
+                        goto out;
+                }
+        } else {
+                btrfs_release_path(root, path);
+
+                if (flags & XATTR_REPLACE) {
+                        /* we couldn't find the attr to replace */
+                        ret = -ENODATA;
+                        goto out;
+                }
+        }
+
+        /* ok we have to create a completely new xattr */
+        ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
+                                      value, size, inode->i_ino);
+        if (ret)
+                goto out;
+        mod = 1;
+
+out:
+        if (mod) {
+                inode->i_ctime = CURRENT_TIME;
+                ret = btrfs_update_inode(trans, root, inode);
+        }
+
+        btrfs_end_transaction(trans, root);
+        btrfs_free_path(path);
+        return ret;
+}
+
+ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+        struct btrfs_key key, found_key;
+        struct inode *inode = dentry->d_inode;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct btrfs_path *path;
+        struct btrfs_item *item;
+        struct extent_buffer *leaf;
+        struct btrfs_dir_item *di;
+        int ret = 0, slot, advance;
+        size_t total_size = 0, size_left = size;
+        unsigned long name_ptr;
+        size_t name_len;
+        u32 nritems;
+
+        /*
+         * ok we want all objects associated with this id.
+         * NOTE: we set key.offset = 0; because we want to start with the
+         * first xattr that we find and walk forward
+         */
+        key.objectid = inode->i_ino;
+        btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
+        key.offset = 0;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+        path->reada = 2;
+
+        /* search for our xattrs */
+        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+        if (ret < 0)
+                goto err;
+        ret = 0;
+        advance = 0;
+        while (1) {
+                leaf = path->nodes[0];
+                nritems = btrfs_header_nritems(leaf);
+                slot = path->slots[0];
+
+                /* this is where we start walking through the path */
+                if (advance || slot >= nritems) {
+                        /*
+                         * if we've reached the last slot in this leaf we need
+                         * to go to the next leaf and reset everything
+                         */
+                        if (slot >= nritems-1) {
+                                ret = btrfs_next_leaf(root, path);
+                                if (ret)
+                                        break;
+                                leaf = path->nodes[0];
+                                nritems = btrfs_header_nritems(leaf);
+                                slot = path->slots[0];
+                        } else {
+                                /*
+                                 * just walking through the slots on this leaf
+                                 */
+                                slot++;
+                                path->slots[0]++;
+                        }
+                }
+                advance = 1;
+
+                item = btrfs_item_nr(leaf, slot);
+                btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+                /* check to make sure this item is what we want */
+                if (found_key.objectid != key.objectid)
+                        break;
+                if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
+                        break;
+
+                di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
+
+                name_len = btrfs_dir_name_len(leaf, di);
+                total_size += name_len + 1;
+
+                /* we are just looking for how big our buffer needs to be */
+                if (!size)
+                        continue;
+
+                if (!buffer || (name_len + 1) > size_left) {
+                        ret = -ERANGE;
+                        goto err;
+                }
+
+                name_ptr = (unsigned long)(di + 1);
+                read_extent_buffer(leaf, buffer, name_ptr, name_len);
+                buffer[name_len] = '\0';
+
+                size_left -= name_len + 1;
+                buffer += name_len + 1;
+        }
+        ret = total_size;
+
+err:
+        btrfs_free_path(path);
+
+        return ret;
+}
+
+/*
+ * List of handlers for synthetic system.* attributes.  All real ondisk
+ * attributes are handled directly.
+ */
+struct xattr_handler *btrfs_xattr_handlers[] = {
+#ifdef CONFIG_FS_POSIX_ACL
+        &btrfs_xattr_acl_access_handler,
+        &btrfs_xattr_acl_default_handler,
+#endif
+        NULL,
+};
+
+/*
+ * Check if the attribute is in a supported namespace.
+ *
+ * This applied after the check for the synthetic attributes in the system
+ * namespace.
+ */
+static bool btrfs_is_valid_xattr(const char *name)
+{
+        return !strncmp(name, XATTR_SECURITY_PREFIX,
+                        XATTR_SECURITY_PREFIX_LEN) ||
+               !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
+               !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
+               !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
+}
+
+ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
+                       void *buffer, size_t size)
+{
+        /*
+         * If this is a request for a synthetic attribute in the system.*
+         * namespace use the generic infrastructure to resolve a handler
+         * for it via sb->s_xattr.
+         */
+        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+                return generic_getxattr(dentry, name, buffer, size);
+
+        if (!btrfs_is_valid_xattr(name))
+                return -EOPNOTSUPP;
+        return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
+}
+
+int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+                   size_t size, int flags)
+{
+        /*
+         * If this is a request for a synthetic attribute in the system.*
+         * namespace use the generic infrastructure to resolve a handler
+         * for it via sb->s_xattr.
+         */
+        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+                return generic_setxattr(dentry, name, value, size, flags);
+
+        if (!btrfs_is_valid_xattr(name))
+                return -EOPNOTSUPP;
+
+        if (size == 0)
+                value = "";  /* empty EA, do not remove */
+        return __btrfs_setxattr(dentry->d_inode, name, value, size, flags);
+}
+
+int btrfs_removexattr(struct dentry *dentry, const char *name)
+{
+        /*
+         * If this is a request for a synthetic attribute in the system.*
+         * namespace use the generic infrastructure to resolve a handler
+         * for it via sb->s_xattr.
+         */
+        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+                return generic_removexattr(dentry, name);
+
+        if (!btrfs_is_valid_xattr(name))
+                return -EOPNOTSUPP;
+        return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
+}