--- /dev/null
+/*
+ * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
+ *
+ * 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/hashtable.h>
+#include "props.h"
+#include "btrfs_inode.h"
+#include "hash.h"
+#include "transaction.h"
+#include "xattr.h"
+
+#define BTRFS_PROP_HANDLERS_HT_BITS 8
+static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
+
+struct prop_handler {
+ struct hlist_node node;
+ const char *xattr_name;
+ int (*validate)(const char *value, size_t len);
+ int (*apply)(struct inode *inode, const char *value, size_t len);
+ const char *(*extract)(struct inode *inode);
+ int inheritable;
+};
+
+static int prop_compression_validate(const char *value, size_t len);
+static int prop_compression_apply(struct inode *inode,
+ const char *value,
+ size_t len);
+static const char *prop_compression_extract(struct inode *inode);
+
+static struct prop_handler prop_handlers[] = {
+ {
+ .xattr_name = XATTR_BTRFS_PREFIX "compression",
+ .validate = prop_compression_validate,
+ .apply = prop_compression_apply,
+ .extract = prop_compression_extract,
+ .inheritable = 1
+ },
+ {
+ .xattr_name = NULL
+ }
+};
+
+void __init btrfs_props_init(void)
+{
+ struct prop_handler *p;
+
+ hash_init(prop_handlers_ht);
+
+ for (p = &prop_handlers[0]; p->xattr_name; p++) {
+ u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
+
+ hash_add(prop_handlers_ht, &p->node, h);
+ }
+}
+
+static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
+{
+ struct hlist_head *h;
+
+ h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
+ if (hlist_empty(h))
+ return NULL;
+
+ return h;
+}
+
+static const struct prop_handler *
+find_prop_handler(const char *name,
+ const struct hlist_head *handlers)
+{
+ struct prop_handler *h;
+
+ if (!handlers) {
+ u64 hash = btrfs_name_hash(name, strlen(name));
+
+ handlers = find_prop_handlers_by_hash(hash);
+ if (!handlers)
+ return NULL;
+ }
+
+ hlist_for_each_entry(h, handlers, node)
+ if (!strcmp(h->xattr_name, name))
+ return h;
+
+ return NULL;
+}
+
+static int __btrfs_set_prop(struct btrfs_trans_handle *trans,
+ struct inode *inode,
+ const char *name,
+ const char *value,
+ size_t value_len,
+ int flags)
+{
+ const struct prop_handler *handler;
+ int ret;
+
+ if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
+ return -EINVAL;
+
+ handler = find_prop_handler(name, NULL);
+ if (!handler)
+ return -EINVAL;
+
+ if (value_len == 0) {
+ ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
+ NULL, 0, flags);
+ if (ret)
+ return ret;
+
+ ret = handler->apply(inode, NULL, 0);
+ ASSERT(ret == 0);
+
+ return ret;
+ }
+
+ ret = handler->validate(value, value_len);
+ if (ret)
+ return ret;
+ ret = __btrfs_setxattr(trans, inode, handler->xattr_name,
+ value, value_len, flags);
+ if (ret)
+ return ret;
+ ret = handler->apply(inode, value, value_len);
+ if (ret) {
+ __btrfs_setxattr(trans, inode, handler->xattr_name,
+ NULL, 0, flags);
+ return ret;
+ }
+
+ set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
+
+ return 0;
+}
+
+int btrfs_set_prop(struct inode *inode,
+ const char *name,
+ const char *value,
+ size_t value_len,
+ int flags)
+{
+ return __btrfs_set_prop(NULL, inode, name, value, value_len, flags);
+}
+
+static int iterate_object_props(struct btrfs_root *root,
+ struct btrfs_path *path,
+ u64 objectid,
+ void (*iterator)(void *,
+ const struct prop_handler *,
+ const char *,
+ size_t),
+ void *ctx)
+{
+ int ret;
+ char *name_buf = NULL;
+ char *value_buf = NULL;
+ int name_buf_len = 0;
+ int value_buf_len = 0;
+
+ while (1) {
+ struct btrfs_key key;
+ struct btrfs_dir_item *di;
+ struct extent_buffer *leaf;
+ u32 total_len, cur, this_len;
+ int slot;
+ const struct hlist_head *handlers;
+
+ slot = path->slots[0];
+ leaf = path->nodes[0];
+
+ if (slot >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto out;
+ else if (ret > 0)
+ break;
+ continue;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (key.objectid != objectid)
+ break;
+ if (key.type != BTRFS_XATTR_ITEM_KEY)
+ break;
+
+ handlers = find_prop_handlers_by_hash(key.offset);
+ if (!handlers)
+ goto next_slot;
+
+ di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
+ cur = 0;
+ total_len = btrfs_item_size_nr(leaf, slot);
+
+ while (cur < total_len) {
+ u32 name_len = btrfs_dir_name_len(leaf, di);
+ u32 data_len = btrfs_dir_data_len(leaf, di);
+ unsigned long name_ptr, data_ptr;
+ const struct prop_handler *handler;
+
+ this_len = sizeof(*di) + name_len + data_len;
+ name_ptr = (unsigned long)(di + 1);
+ data_ptr = name_ptr + name_len;
+
+ if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
+ memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
+ name_ptr,
+ XATTR_BTRFS_PREFIX_LEN))
+ goto next_dir_item;
+
+ if (name_len >= name_buf_len) {
+ kfree(name_buf);
+ name_buf_len = name_len + 1;
+ name_buf = kmalloc(name_buf_len, GFP_NOFS);
+ if (!name_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ read_extent_buffer(leaf, name_buf, name_ptr, name_len);
+ name_buf[name_len] = '\0';
+
+ handler = find_prop_handler(name_buf, handlers);
+ if (!handler)
+ goto next_dir_item;
+
+ if (data_len > value_buf_len) {
+ kfree(value_buf);
+ value_buf_len = data_len;
+ value_buf = kmalloc(data_len, GFP_NOFS);
+ if (!value_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ read_extent_buffer(leaf, value_buf, data_ptr, data_len);
+
+ iterator(ctx, handler, value_buf, data_len);
+next_dir_item:
+ cur += this_len;
+ di = (struct btrfs_dir_item *)((char *) di + this_len);
+ }
+
+next_slot:
+ path->slots[0]++;
+ }
+
+ ret = 0;
+out:
+ btrfs_release_path(path);
+ kfree(name_buf);
+ kfree(value_buf);
+
+ return ret;
+}
+
+static void inode_prop_iterator(void *ctx,
+ const struct prop_handler *handler,
+ const char *value,
+ size_t len)
+{
+ struct inode *inode = ctx;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ int ret;
+
+ ret = handler->apply(inode, value, len);
+ if (unlikely(ret))
+ btrfs_warn(root->fs_info,
+ "error applying prop %s to ino %llu (root %llu): %d",
+ handler->xattr_name, btrfs_ino(inode),
+ root->root_key.objectid, ret);
+ else
+ set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
+}
+
+int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ u64 ino = btrfs_ino(inode);
+ int ret;
+
+ ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
+
+ return ret;
+}
+
+static int inherit_props(struct btrfs_trans_handle *trans,
+ struct inode *inode,
+ struct inode *parent)
+{
+ const struct prop_handler *h;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ int ret;
+
+ if (!test_bit(BTRFS_INODE_HAS_PROPS,
+ &BTRFS_I(parent)->runtime_flags))
+ return 0;
+
+ for (h = &prop_handlers[0]; h->xattr_name; h++) {
+ const char *value;
+ u64 num_bytes;
+
+ if (!h->inheritable)
+ continue;
+
+ value = h->extract(parent);
+ if (!value)
+ continue;
+
+ num_bytes = btrfs_calc_trans_metadata_size(root, 1);
+ ret = btrfs_block_rsv_add(root, trans->block_rsv,
+ num_bytes, BTRFS_RESERVE_NO_FLUSH);
+ if (ret)
+ goto out;
+ ret = __btrfs_set_prop(trans, inode, h->xattr_name,
+ value, strlen(value), 0);
+ btrfs_block_rsv_release(root, trans->block_rsv, num_bytes);
+ if (ret)
+ goto out;
+ }
+ ret = 0;
+out:
+ return ret;
+}
+
+int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
+ struct inode *inode,
+ struct inode *dir)
+{
+ if (!dir)
+ return 0;
+
+ return inherit_props(trans, inode, dir);
+}
+
+int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_root *parent_root)
+{
+ struct btrfs_key key;
+ struct inode *parent_inode, *child_inode;
+ int ret;
+
+ key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+
+ parent_inode = btrfs_iget(parent_root->fs_info->sb, &key,
+ parent_root, NULL);
+ if (IS_ERR(parent_inode))
+ return PTR_ERR(parent_inode);
+
+ child_inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
+ if (IS_ERR(child_inode)) {
+ iput(parent_inode);
+ return PTR_ERR(child_inode);
+ }
+
+ ret = inherit_props(trans, child_inode, parent_inode);
+ iput(child_inode);
+ iput(parent_inode);
+
+ return ret;
+}
+
+static int prop_compression_validate(const char *value, size_t len)
+{
+ if (!strncmp("lzo", value, len))
+ return 0;
+ else if (!strncmp("zlib", value, len))
+ return 0;
+
+ return -EINVAL;
+}
+
+static int prop_compression_apply(struct inode *inode,
+ const char *value,
+ size_t len)
+{
+ int type;
+
+ if (len == 0) {
+ BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
+ BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
+ BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
+
+ return 0;
+ }
+
+ if (!strncmp("lzo", value, len))
+ type = BTRFS_COMPRESS_LZO;
+ else if (!strncmp("zlib", value, len))
+ type = BTRFS_COMPRESS_ZLIB;
+ else
+ return -EINVAL;
+
+ BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
+ BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
+ BTRFS_I(inode)->force_compress = type;
+
+ return 0;
+}
+
+static const char *prop_compression_extract(struct inode *inode)
+{
+ switch (BTRFS_I(inode)->force_compress) {
+ case BTRFS_COMPRESS_ZLIB:
+ return "zlib";
+ case BTRFS_COMPRESS_LZO:
+ return "lzo";
+ }
+
+ return NULL;
+}
+
+
Code Review / kvmfornfv.git / blobdiff