microblaze: Fix "kstack=" parsing
[linux-2.6.git] / fs / btrfs / xattr.c
index 33caaf5..193b58f 100644 (file)
 #include <linux/slab.h>
 #include <linux/rwsem.h>
 #include <linux/xattr.h>
+#include <linux/security.h>
 #include "ctree.h"
 #include "btrfs_inode.h"
 #include "transaction.h"
 #include "xattr.h"
 #include "disk-io.h"
 
-static struct xattr_handler *btrfs_xattr_handler_map[] = {
-       [BTRFS_XATTR_INDEX_USER]                = &btrfs_xattr_user_handler,
-       [BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS]    = &btrfs_xattr_acl_access_handler,
-       [BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT]   = &btrfs_xattr_acl_default_handler,
-       [BTRFS_XATTR_INDEX_TRUSTED]             = &btrfs_xattr_trusted_handler,
-       [BTRFS_XATTR_INDEX_SECURITY]            = &btrfs_xattr_security_handler,
-       [BTRFS_XATTR_INDEX_SYSTEM]              = &btrfs_xattr_system_handler,
-};
-
-struct xattr_handler *btrfs_xattr_handlers[] = {
-       &btrfs_xattr_user_handler,
-       &btrfs_xattr_acl_access_handler,
-       &btrfs_xattr_acl_default_handler,
-       &btrfs_xattr_trusted_handler,
-       &btrfs_xattr_security_handler,
-       &btrfs_xattr_system_handler,
-       NULL,
-};
-
-/*
- * @param name - the xattr name
- * @return - the xattr_handler for the xattr, NULL if its not found
- *
- * use this with listxattr where we don't already know the type of xattr we
- * have
- */
-static struct xattr_handler *find_btrfs_xattr_handler(struct extent_buffer *l,
-                                                     unsigned long name_ptr,
-                                                     u16 name_len)
-{
-       struct xattr_handler *handler = NULL;
-       int i = 0;
-
-       for (handler = btrfs_xattr_handlers[i]; handler != NULL; i++,
-            handler = btrfs_xattr_handlers[i]) {
-               u16 prefix_len = strlen(handler->prefix);
-
-               if (name_len < prefix_len)
-                       continue;
-
-               if (memcmp_extent_buffer(l, handler->prefix, name_ptr,
-                                        prefix_len) == 0)
-                       break;
-       }
-
-       return handler;
-}
-
-/*
- * @param name_index - the index for the xattr handler
- * @return the xattr_handler if we found it, NULL otherwise
- *
- * use this if we know the type of the xattr already
- */
-static struct xattr_handler *btrfs_xattr_handler(int name_index)
-{
-       struct xattr_handler *handler = NULL;
-
-       if (name_index >= 0 &&
-           name_index < ARRAY_SIZE(btrfs_xattr_handler_map))
-               handler = btrfs_xattr_handler_map[name_index];
-
-       return handler;
-}
-
-static inline char *get_name(const char *name, int name_index)
-{
-       char *ret = NULL;
-       struct xattr_handler *handler = btrfs_xattr_handler(name_index);
-       int prefix_len;
-
-       if (!handler)
-               return ret;
-
-       prefix_len = strlen(handler->prefix);
-
-       ret = kmalloc(strlen(name) + prefix_len + 1, GFP_KERNEL);
-       if (!ret)
-               return ret;
-
-       memcpy(ret, handler->prefix, prefix_len);
-       memcpy(ret+prefix_len, name, strlen(name));
-       ret[prefix_len + strlen(name)] = '\0';
-
-       return ret;
-}
-
-size_t btrfs_xattr_generic_list(struct inode *inode, char *list,
-                               size_t list_size, const char *name,
-                               size_t name_len)
-{
-       if (list && (name_len+1) <= list_size) {
-               memcpy(list, name, name_len);
-               list[name_len] = '\0';
-       } else
-               return -ERANGE;
-
-       return name_len+1;
-}
 
-ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
-                       const char *attr_name, void *buffer, size_t size)
+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;
-       struct xattr_handler *handler = btrfs_xattr_handler(name_index);
        int ret = 0;
        unsigned long data_ptr;
-       char *name;
-
-       if (!handler)
-               return -EOPNOTSUPP;
-
-       /* just in case... */
-       if (*attr_name == '\0')
-               return -EINVAL;
-
-       name = get_name(attr_name, name_index);
-       if (!name)
-               return -ENOMEM;
 
        path = btrfs_alloc_path();
-       if (!path) {
-               kfree(name);
+       if (!path)
                return -ENOMEM;
-       }
 
-       mutex_lock(&root->fs_info->fs_mutex);
        /* lookup the xattr by name */
        di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
                                strlen(name), 0);
-       if (!di || IS_ERR(di)) {
+       if (!di) {
                ret = -ENODATA;
                goto out;
+       } else if (IS_ERR(di)) {
+               ret = PTR_ERR(di);
+               goto out;
        }
 
        leaf = path->nodes[0];
@@ -177,6 +66,14 @@ ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
                ret = -ERANGE;
                goto out;
        }
+
+       /*
+        * The way things are packed into the leaf is like this
+        * |struct btrfs_dir_item|name|data|
+        * where name is the xattr name, so security.foo, and data is the
+        * content of the xattr.  data_ptr points to the location in memory
+        * where the data starts in the in memory leaf
+        */
        data_ptr = (unsigned long)((char *)(di + 1) +
                                   btrfs_dir_name_len(leaf, di));
        read_extent_buffer(leaf, buffer, data_ptr,
@@ -184,44 +81,26 @@ ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
        ret = btrfs_dir_data_len(leaf, di);
 
 out:
-       mutex_unlock(&root->fs_info->fs_mutex);
-       kfree(name);
        btrfs_free_path(path);
        return ret;
 }
 
-int btrfs_xattr_set(struct inode *inode, int name_index,
-                   const char *attr_name, const void *value, size_t size,
-                   int flags)
+static int do_setxattr(struct btrfs_trans_handle *trans,
+                      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;
-       struct xattr_handler *handler = btrfs_xattr_handler(name_index);
-       char *name;
-       int ret = 0, mod = 0;
-
-       if (!handler)
-               return -EOPNOTSUPP;
+       size_t name_len = strlen(name);
+       int ret = 0;
 
-       /* just in case... */
-       if (*attr_name == '\0')
-               return -EINVAL;
-
-       name = get_name(attr_name, name_index);
-       if (!name)
-               return -ENOMEM;
+       if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
+               return -ENOSPC;
 
        path = btrfs_alloc_path();
-       if (!path) {
-               kfree(name);
+       if (!path)
                return -ENOMEM;
-       }
-
-       mutex_lock(&root->fs_info->fs_mutex);
-       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,
@@ -240,39 +119,62 @@ int btrfs_xattr_set(struct inode *inode, int name_index,
                }
 
                ret = btrfs_delete_one_dir_name(trans, root, path, di);
-               if (ret)
-                       goto out;
+               BUG_ON(ret);
                btrfs_release_path(root, path);
 
                /* if we don't have a value then we are removing the xattr */
-               if (!value) {
-                       mod = 1;
+               if (!value)
+                       goto out;
+       } else {
+               btrfs_release_path(root, path);
+
+               if (flags & XATTR_REPLACE) {
+                       /* we couldn't find the attr to replace */
+                       ret = -ENODATA;
                        goto out;
                }
-       } else if (flags & XATTR_REPLACE) {
-               /* we couldn't find the attr to replace, so error out */
-               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);
+       ret = btrfs_insert_xattr_item(trans, root, path, inode->i_ino,
+                                     name, name_len, value, size);
+       BUG_ON(ret);
+out:
+       btrfs_free_path(path);
+       return ret;
+}
+
+int __btrfs_setxattr(struct btrfs_trans_handle *trans,
+                    struct inode *inode, const char *name,
+                    const void *value, size_t size, int flags)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       int ret;
+
+       if (trans)
+               return do_setxattr(trans, inode, name, value, size, flags);
+
+       ret = btrfs_reserve_metadata_space(root, 2);
        if (ret)
-               goto out;
-       mod = 1;
+               return ret;
 
-out:
-       if (mod) {
-               inode->i_ctime = CURRENT_TIME;
-               ret = btrfs_update_inode(trans, root, inode);
+       trans = btrfs_start_transaction(root, 1);
+       if (!trans) {
+               ret = -ENOMEM;
+               goto out;
        }
+       btrfs_set_trans_block_group(trans, inode);
 
-       btrfs_end_transaction(trans, root);
-       mutex_unlock(&root->fs_info->fs_mutex);
-       kfree(name);
-       btrfs_free_path(path);
+       ret = do_setxattr(trans, inode, name, value, size, flags);
+       if (ret)
+               goto out;
 
+       inode->i_ctime = CURRENT_TIME;
+       ret = btrfs_update_inode(trans, root, inode);
+       BUG_ON(ret);
+out:
+       btrfs_end_transaction_throttle(trans, root);
+       btrfs_unreserve_metadata_space(root, 2);
        return ret;
 }
 
@@ -285,11 +187,10 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
        struct btrfs_item *item;
        struct extent_buffer *leaf;
        struct btrfs_dir_item *di;
-       struct xattr_handler *handler;
        int ret = 0, slot, advance;
-       size_t total_size = 0, size_left = size, written;
+       size_t total_size = 0, size_left = size;
        unsigned long name_ptr;
-       char *name;
+       size_t name_len;
        u32 nritems;
 
        /*
@@ -306,13 +207,10 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
                return -ENOMEM;
        path->reada = 2;
 
-       mutex_lock(&root->fs_info->fs_mutex);
-
        /* 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];
@@ -353,145 +251,142 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 
                di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
 
-               total_size += btrfs_dir_name_len(leaf, di)+1;
+               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;
 
-               /* find our handler for this xattr */
-               name_ptr = (unsigned long)(di + 1);
-               handler = find_btrfs_xattr_handler(leaf, name_ptr,
-                                                  btrfs_dir_name_len(leaf, di));
-               if (!handler) {
-                       printk(KERN_ERR "btrfs: unsupported xattr found\n");
-                       continue;
-               }
-
-               name = kmalloc(btrfs_dir_name_len(leaf, di), GFP_KERNEL);
-               read_extent_buffer(leaf, name, name_ptr,
-                                  btrfs_dir_name_len(leaf, di));
-
-               /* call the list function associated with this xattr */
-               written = handler->list(inode, buffer, size_left, name,
-                                       btrfs_dir_name_len(leaf, di));
-               kfree(name);
-
-               if (written < 0) {
+               if (!buffer || (name_len + 1) > size_left) {
                        ret = -ERANGE;
-                       break;
+                       goto err;
                }
 
-               size_left -= written;
-               buffer += written;
+               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:
-       mutex_unlock(&root->fs_info->fs_mutex);
        btrfs_free_path(path);
 
        return ret;
 }
 
 /*
- * delete all the xattrs associated with the inode.  fs_mutex should be
- * held when we come into here
+ * List of handlers for synthetic system.* attributes.  All real ondisk
+ * attributes are handled directly.
+ */
+struct xattr_handler *btrfs_xattr_handlers[] = {
+#ifdef CONFIG_BTRFS_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.
  */
-int btrfs_delete_xattrs(struct btrfs_trans_handle *trans,
-                       struct btrfs_root *root, struct inode *inode)
+static bool btrfs_is_valid_xattr(const char *name)
 {
-       struct btrfs_path *path;
-       struct btrfs_key key, found_key;
-       struct btrfs_item *item;
-       struct extent_buffer *leaf;
-       int ret;
+       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);
+}
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-       path->reada = -1;
-       key.objectid = inode->i_ino;
-       btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
-       key.offset = (u64)-1;
+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);
 
-       while(1) {
-               /* look for our next xattr */
-               ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
-               if (ret < 0)
-                       goto out;
-               BUG_ON(ret == 0);
+       if (!btrfs_is_valid_xattr(name))
+               return -EOPNOTSUPP;
+       return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
+}
 
-               if (path->slots[0] == 0)
-                       break;
+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);
 
-               path->slots[0]--;
-               leaf = path->nodes[0];
-               item = btrfs_item_nr(leaf, path->slots[0]);
-               btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+       if (!btrfs_is_valid_xattr(name))
+               return -EOPNOTSUPP;
 
-               if (found_key.objectid != key.objectid)
-                       break;
-               if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
-                       break;
+       if (size == 0)
+               value = "";  /* empty EA, do not remove */
 
-               ret = btrfs_del_item(trans, root, path);
-               BUG_ON(ret);
-               btrfs_release_path(root, path);
-       }
-       ret = 0;
-out:
-       btrfs_free_path(path);
+       return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
+                               flags);
+}
 
-       return ret;
+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(NULL, dentry->d_inode, name, NULL, 0,
+                               XATTR_REPLACE);
 }
 
-/*
- * Handler functions
- */
-#define BTRFS_XATTR_SETGET_FUNCS(name, index)                          \
-static int btrfs_xattr_##name##_get(struct inode *inode,               \
-                                   const char *name, void *value,      \
-                                   size_t size)                        \
-{                                                                      \
-       return btrfs_xattr_get(inode, index, name, value, size);        \
-}                                                                      \
-static int btrfs_xattr_##name##_set(struct inode *inode,               \
-                                   const char *name, const void *value,\
-                                   size_t size, int flags)             \
-{                                                                      \
-       return btrfs_xattr_set(inode, index, name, value, size, flags); \
-}                                                                      \
-
-BTRFS_XATTR_SETGET_FUNCS(security, BTRFS_XATTR_INDEX_SECURITY);
-BTRFS_XATTR_SETGET_FUNCS(system, BTRFS_XATTR_INDEX_SYSTEM);
-BTRFS_XATTR_SETGET_FUNCS(user, BTRFS_XATTR_INDEX_USER);
-BTRFS_XATTR_SETGET_FUNCS(trusted, BTRFS_XATTR_INDEX_TRUSTED);
-
-struct xattr_handler btrfs_xattr_security_handler = {
-       .prefix = XATTR_SECURITY_PREFIX,
-       .list   = btrfs_xattr_generic_list,
-       .get    = btrfs_xattr_security_get,
-       .set    = btrfs_xattr_security_set,
-};
+int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
+                             struct inode *inode, struct inode *dir)
+{
+       int err;
+       size_t len;
+       void *value;
+       char *suffix;
+       char *name;
 
-struct xattr_handler btrfs_xattr_system_handler = {
-       .prefix = XATTR_SYSTEM_PREFIX,
-       .list   = btrfs_xattr_generic_list,
-       .get    = btrfs_xattr_system_get,
-       .set    = btrfs_xattr_system_set,
-};
+       err = security_inode_init_security(inode, dir, &suffix, &value, &len);
+       if (err) {
+               if (err == -EOPNOTSUPP)
+                       return 0;
+               return err;
+       }
 
-struct xattr_handler btrfs_xattr_user_handler = {
-       .prefix = XATTR_USER_PREFIX,
-       .list   = btrfs_xattr_generic_list,
-       .get    = btrfs_xattr_user_get,
-       .set    = btrfs_xattr_user_set,
-};
+       name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
+                      GFP_NOFS);
+       if (!name) {
+               err = -ENOMEM;
+       } else {
+               strcpy(name, XATTR_SECURITY_PREFIX);
+               strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
+               err = __btrfs_setxattr(trans, inode, name, value, len, 0);
+               kfree(name);
+       }
 
-struct xattr_handler btrfs_xattr_trusted_handler = {
-       .prefix = XATTR_TRUSTED_PREFIX,
-       .list   = btrfs_xattr_generic_list,
-       .get    = btrfs_xattr_trusted_get,
-       .set    = btrfs_xattr_trusted_set,
-};
+       kfree(suffix);
+       kfree(value);
+       return err;
+}