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-rw-r--r--fs/btrfs/dir-item.c482
1 files changed, 482 insertions, 0 deletions
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
new file mode 100644
index 000000000..1752625fb
--- /dev/null
+++ b/fs/btrfs/dir-item.c
@@ -0,0 +1,482 @@
+/*
+ * Copyright (C) 2007 Oracle. 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 "ctree.h"
+#include "disk-io.h"
+#include "hash.h"
+#include "transaction.h"
+
+/*
+ * insert a name into a directory, doing overflow properly if there is a hash
+ * collision. data_size indicates how big the item inserted should be. On
+ * success a struct btrfs_dir_item pointer is returned, otherwise it is
+ * an ERR_PTR.
+ *
+ * The name is not copied into the dir item, you have to do that yourself.
+ */
+static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
+ *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *cpu_key,
+ u32 data_size,
+ const char *name,
+ int name_len)
+{
+ int ret;
+ char *ptr;
+ struct btrfs_item *item;
+ struct extent_buffer *leaf;
+
+ ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
+ if (ret == -EEXIST) {
+ struct btrfs_dir_item *di;
+ di = btrfs_match_dir_item_name(root, path, name, name_len);
+ if (di)
+ return ERR_PTR(-EEXIST);
+ btrfs_extend_item(root, path, data_size);
+ } else if (ret < 0)
+ return ERR_PTR(ret);
+ WARN_ON(ret > 0);
+ leaf = path->nodes[0];
+ item = btrfs_item_nr(path->slots[0]);
+ ptr = btrfs_item_ptr(leaf, path->slots[0], char);
+ BUG_ON(data_size > btrfs_item_size(leaf, item));
+ ptr += btrfs_item_size(leaf, item) - data_size;
+ return (struct btrfs_dir_item *)ptr;
+}
+
+/*
+ * xattrs work a lot like directories, this inserts an xattr item
+ * into the tree
+ */
+int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, u64 objectid,
+ const char *name, u16 name_len,
+ const void *data, u16 data_len)
+{
+ int ret = 0;
+ struct btrfs_dir_item *dir_item;
+ unsigned long name_ptr, data_ptr;
+ struct btrfs_key key, location;
+ struct btrfs_disk_key disk_key;
+ struct extent_buffer *leaf;
+ u32 data_size;
+
+ BUG_ON(name_len + data_len > BTRFS_MAX_XATTR_SIZE(root));
+
+ key.objectid = objectid;
+ key.type = BTRFS_XATTR_ITEM_KEY;
+ key.offset = btrfs_name_hash(name, name_len);
+
+ data_size = sizeof(*dir_item) + name_len + data_len;
+ dir_item = insert_with_overflow(trans, root, path, &key, data_size,
+ name, name_len);
+ if (IS_ERR(dir_item))
+ return PTR_ERR(dir_item);
+ memset(&location, 0, sizeof(location));
+
+ leaf = path->nodes[0];
+ btrfs_cpu_key_to_disk(&disk_key, &location);
+ btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
+ btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
+ btrfs_set_dir_name_len(leaf, dir_item, name_len);
+ btrfs_set_dir_transid(leaf, dir_item, trans->transid);
+ btrfs_set_dir_data_len(leaf, dir_item, data_len);
+ name_ptr = (unsigned long)(dir_item + 1);
+ data_ptr = (unsigned long)((char *)name_ptr + name_len);
+
+ write_extent_buffer(leaf, name, name_ptr, name_len);
+ write_extent_buffer(leaf, data, data_ptr, data_len);
+ btrfs_mark_buffer_dirty(path->nodes[0]);
+
+ return ret;
+}
+
+/*
+ * insert a directory item in the tree, doing all the magic for
+ * both indexes. 'dir' indicates which objectid to insert it into,
+ * 'location' is the key to stuff into the directory item, 'type' is the
+ * type of the inode we're pointing to, and 'index' is the sequence number
+ * to use for the second index (if one is created).
+ * Will return 0 or -ENOMEM
+ */
+int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, const char *name, int name_len,
+ struct inode *dir, struct btrfs_key *location,
+ u8 type, u64 index)
+{
+ int ret = 0;
+ int ret2 = 0;
+ struct btrfs_path *path;
+ struct btrfs_dir_item *dir_item;
+ struct extent_buffer *leaf;
+ unsigned long name_ptr;
+ struct btrfs_key key;
+ struct btrfs_disk_key disk_key;
+ u32 data_size;
+
+ key.objectid = btrfs_ino(dir);
+ key.type = BTRFS_DIR_ITEM_KEY;
+ key.offset = btrfs_name_hash(name, name_len);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->leave_spinning = 1;
+
+ btrfs_cpu_key_to_disk(&disk_key, location);
+
+ data_size = sizeof(*dir_item) + name_len;
+ dir_item = insert_with_overflow(trans, root, path, &key, data_size,
+ name, name_len);
+ if (IS_ERR(dir_item)) {
+ ret = PTR_ERR(dir_item);
+ if (ret == -EEXIST)
+ goto second_insert;
+ goto out_free;
+ }
+
+ leaf = path->nodes[0];
+ btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
+ btrfs_set_dir_type(leaf, dir_item, type);
+ btrfs_set_dir_data_len(leaf, dir_item, 0);
+ btrfs_set_dir_name_len(leaf, dir_item, name_len);
+ btrfs_set_dir_transid(leaf, dir_item, trans->transid);
+ name_ptr = (unsigned long)(dir_item + 1);
+
+ write_extent_buffer(leaf, name, name_ptr, name_len);
+ btrfs_mark_buffer_dirty(leaf);
+
+second_insert:
+ /* FIXME, use some real flag for selecting the extra index */
+ if (root == root->fs_info->tree_root) {
+ ret = 0;
+ goto out_free;
+ }
+ btrfs_release_path(path);
+
+ ret2 = btrfs_insert_delayed_dir_index(trans, root, name, name_len, dir,
+ &disk_key, type, index);
+out_free:
+ btrfs_free_path(path);
+ if (ret)
+ return ret;
+ if (ret2)
+ return ret2;
+ return 0;
+}
+
+/*
+ * lookup a directory item based on name. 'dir' is the objectid
+ * we're searching in, and 'mod' tells us if you plan on deleting the
+ * item (use mod < 0) or changing the options (use mod > 0)
+ */
+struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, u64 dir,
+ const char *name, int name_len,
+ int mod)
+{
+ int ret;
+ struct btrfs_key key;
+ int ins_len = mod < 0 ? -1 : 0;
+ int cow = mod != 0;
+
+ key.objectid = dir;
+ key.type = BTRFS_DIR_ITEM_KEY;
+
+ key.offset = btrfs_name_hash(name, name_len);
+
+ ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0)
+ return NULL;
+
+ return btrfs_match_dir_item_name(root, path, name, name_len);
+}
+
+int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
+ const char *name, int name_len)
+{
+ int ret;
+ struct btrfs_key key;
+ struct btrfs_dir_item *di;
+ int data_size;
+ struct extent_buffer *leaf;
+ int slot;
+ struct btrfs_path *path;
+
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = dir;
+ key.type = BTRFS_DIR_ITEM_KEY;
+ key.offset = btrfs_name_hash(name, name_len);
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+
+ /* return back any errors */
+ if (ret < 0)
+ goto out;
+
+ /* nothing found, we're safe */
+ if (ret > 0) {
+ ret = 0;
+ goto out;
+ }
+
+ /* we found an item, look for our name in the item */
+ di = btrfs_match_dir_item_name(root, path, name, name_len);
+ if (di) {
+ /* our exact name was found */
+ ret = -EEXIST;
+ goto out;
+ }
+
+ /*
+ * see if there is room in the item to insert this
+ * name
+ */
+ data_size = sizeof(*di) + name_len;
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ if (data_size + btrfs_item_size_nr(leaf, slot) +
+ sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root)) {
+ ret = -EOVERFLOW;
+ } else {
+ /* plenty of insertion room */
+ ret = 0;
+ }
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * lookup a directory item based on index. 'dir' is the objectid
+ * we're searching in, and 'mod' tells us if you plan on deleting the
+ * item (use mod < 0) or changing the options (use mod > 0)
+ *
+ * The name is used to make sure the index really points to the name you were
+ * looking for.
+ */
+struct btrfs_dir_item *
+btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, u64 dir,
+ u64 objectid, const char *name, int name_len,
+ int mod)
+{
+ int ret;
+ struct btrfs_key key;
+ int ins_len = mod < 0 ? -1 : 0;
+ int cow = mod != 0;
+
+ key.objectid = dir;
+ key.type = BTRFS_DIR_INDEX_KEY;
+ key.offset = objectid;
+
+ ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0)
+ return ERR_PTR(-ENOENT);
+ return btrfs_match_dir_item_name(root, path, name, name_len);
+}
+
+struct btrfs_dir_item *
+btrfs_search_dir_index_item(struct btrfs_root *root,
+ struct btrfs_path *path, u64 dirid,
+ const char *name, int name_len)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_dir_item *di;
+ struct btrfs_key key;
+ u32 nritems;
+ int ret;
+
+ key.objectid = dirid;
+ key.type = BTRFS_DIR_INDEX_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+
+ while (1) {
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0)
+ break;
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ continue;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
+ break;
+
+ di = btrfs_match_dir_item_name(root, path, name, name_len);
+ if (di)
+ return di;
+
+ path->slots[0]++;
+ }
+ return NULL;
+}
+
+struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, u64 dir,
+ const char *name, u16 name_len,
+ int mod)
+{
+ int ret;
+ struct btrfs_key key;
+ int ins_len = mod < 0 ? -1 : 0;
+ int cow = mod != 0;
+
+ key.objectid = dir;
+ key.type = BTRFS_XATTR_ITEM_KEY;
+ key.offset = btrfs_name_hash(name, name_len);
+ ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0)
+ return NULL;
+
+ return btrfs_match_dir_item_name(root, path, name, name_len);
+}
+
+/*
+ * helper function to look at the directory item pointed to by 'path'
+ * this walks through all the entries in a dir item and finds one
+ * for a specific name.
+ */
+struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
+ struct btrfs_path *path,
+ const char *name, int name_len)
+{
+ struct btrfs_dir_item *dir_item;
+ unsigned long name_ptr;
+ u32 total_len;
+ u32 cur = 0;
+ u32 this_len;
+ struct extent_buffer *leaf;
+
+ leaf = path->nodes[0];
+ dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
+ if (verify_dir_item(root, leaf, dir_item))
+ return NULL;
+
+ total_len = btrfs_item_size_nr(leaf, path->slots[0]);
+ while (cur < total_len) {
+ this_len = sizeof(*dir_item) +
+ btrfs_dir_name_len(leaf, dir_item) +
+ btrfs_dir_data_len(leaf, dir_item);
+ name_ptr = (unsigned long)(dir_item + 1);
+
+ if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
+ memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
+ return dir_item;
+
+ cur += this_len;
+ dir_item = (struct btrfs_dir_item *)((char *)dir_item +
+ this_len);
+ }
+ return NULL;
+}
+
+/*
+ * given a pointer into a directory item, delete it. This
+ * handles items that have more than one entry in them.
+ */
+int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_dir_item *di)
+{
+
+ struct extent_buffer *leaf;
+ u32 sub_item_len;
+ u32 item_len;
+ int ret = 0;
+
+ leaf = path->nodes[0];
+ sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
+ btrfs_dir_data_len(leaf, di);
+ item_len = btrfs_item_size_nr(leaf, path->slots[0]);
+ if (sub_item_len == item_len) {
+ ret = btrfs_del_item(trans, root, path);
+ } else {
+ /* MARKER */
+ unsigned long ptr = (unsigned long)di;
+ unsigned long start;
+
+ start = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
+ item_len - (ptr + sub_item_len - start));
+ btrfs_truncate_item(root, path, item_len - sub_item_len, 1);
+ }
+ return ret;
+}
+
+int verify_dir_item(struct btrfs_root *root,
+ struct extent_buffer *leaf,
+ struct btrfs_dir_item *dir_item)
+{
+ u16 namelen = BTRFS_NAME_LEN;
+ u8 type = btrfs_dir_type(leaf, dir_item);
+
+ if (type >= BTRFS_FT_MAX) {
+ btrfs_crit(root->fs_info, "invalid dir item type: %d",
+ (int)type);
+ return 1;
+ }
+
+ if (type == BTRFS_FT_XATTR)
+ namelen = XATTR_NAME_MAX;
+
+ if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
+ btrfs_crit(root->fs_info, "invalid dir item name len: %u",
+ (unsigned)btrfs_dir_data_len(leaf, dir_item));
+ return 1;
+ }
+
+ /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
+ if ((btrfs_dir_data_len(leaf, dir_item) +
+ btrfs_dir_name_len(leaf, dir_item)) > BTRFS_MAX_XATTR_SIZE(root)) {
+ btrfs_crit(root->fs_info, "invalid dir item name + data len: %u + %u",
+ (unsigned)btrfs_dir_name_len(leaf, dir_item),
+ (unsigned)btrfs_dir_data_len(leaf, dir_item));
+ return 1;
+ }
+
+ return 0;
+}
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