Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 439 insertions, 0 deletions

diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
new file mode 100644
index 000000000..fdab48c1a
--- /dev/null
+++ b/fs/btrfs/dir-item.c
@@ -0,0 +1,439 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ */
+
+#include "ctree.h"
+#include "disk-io.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)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	int ret;
+	char *ptr;
+	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(fs_info, path, name, name_len);
+		if (di)
+			return ERR_PTR(-EEXIST);
+		btrfs_extend_item(path, data_size);
+	} else if (ret < 0)
+		return ERR_PTR(ret);
+	WARN_ON(ret > 0);
+	leaf = path->nodes[0];
+	ptr = btrfs_item_ptr(leaf, path->slots[0], char);
+	ASSERT(data_size <= btrfs_item_size(leaf, path->slots[0]));
+	ptr += btrfs_item_size(leaf, path->slots[0]) - 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;
+
+	if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info))
+		return -ENOSPC;
+
+	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,
+			  const struct fscrypt_str *name, struct btrfs_inode *dir,
+			  struct btrfs_key *location, u8 type, u64 index)
+{
+	int ret = 0;
+	int ret2 = 0;
+	struct btrfs_root *root = dir->root;
+	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, name->len);
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	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, 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, 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, name->name, name->len, dir,
+					      &disk_key, type, index);
+out_free:
+	btrfs_free_path(path);
+	if (ret)
+		return ret;
+	if (ret2)
+		return ret2;
+	return 0;
+}
+
+static struct btrfs_dir_item *btrfs_lookup_match_dir(
+			struct btrfs_trans_handle *trans,
+			struct btrfs_root *root, struct btrfs_path *path,
+			struct btrfs_key *key, const char *name,
+			int name_len, int mod)
+{
+	const int ins_len = (mod < 0 ? -1 : 0);
+	const int cow = (mod != 0);
+	int ret;
+
+	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->fs_info, path, name, name_len);
+}
+
+/*
+ * Lookup for a directory item by name.
+ *
+ * @trans:	The transaction handle to use. Can be NULL if @mod is 0.
+ * @root:	The root of the target tree.
+ * @path:	Path to use for the search.
+ * @dir:	The inode number (objectid) of the directory.
+ * @name:	The name associated to the directory entry we are looking for.
+ * @name_len:	The length of the name.
+ * @mod:	Used to indicate if the tree search is meant for a read only
+ *		lookup, for a modification lookup or for a deletion lookup, so
+ *		its value should be 0, 1 or -1, respectively.
+ *
+ * Returns: NULL if the dir item does not exists, an error pointer if an error
+ * happened, or a pointer to a dir item if a dir item exists for the given name.
+ */
+struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
+					     struct btrfs_root *root,
+					     struct btrfs_path *path, u64 dir,
+					     const struct fscrypt_str *name,
+					     int mod)
+{
+	struct btrfs_key key;
+	struct btrfs_dir_item *di;
+
+	key.objectid = dir;
+	key.type = BTRFS_DIR_ITEM_KEY;
+	key.offset = btrfs_name_hash(name->name, name->len);
+
+	di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
+				    name->len, mod);
+	if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
+		return NULL;
+
+	return di;
+}
+
+int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
+				   const struct fscrypt_str *name)
+{
+	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, name->len);
+
+	di = btrfs_lookup_match_dir(NULL, root, path, &key, name->name,
+				    name->len, 0);
+	if (IS_ERR(di)) {
+		ret = PTR_ERR(di);
+		/* Nothing found, we're safe */
+		if (ret == -ENOENT) {
+			ret = 0;
+			goto out;
+		}
+
+		if (ret < 0)
+			goto out;
+	}
+
+	/* we found an item, look for our name in the item */
+	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(leaf, slot) +
+	    sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
+		ret = -EOVERFLOW;
+	} else {
+		/* plenty of insertion room */
+		ret = 0;
+	}
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/*
+ * Lookup for a directory index item by name and index number.
+ *
+ * @trans:	The transaction handle to use. Can be NULL if @mod is 0.
+ * @root:	The root of the target tree.
+ * @path:	Path to use for the search.
+ * @dir:	The inode number (objectid) of the directory.
+ * @index:	The index number.
+ * @name:	The name associated to the directory entry we are looking for.
+ * @name_len:	The length of the name.
+ * @mod:	Used to indicate if the tree search is meant for a read only
+ *		lookup, for a modification lookup or for a deletion lookup, so
+ *		its value should be 0, 1 or -1, respectively.
+ *
+ * Returns: NULL if the dir index item does not exists, an error pointer if an
+ * error happened, or a pointer to a dir item if the dir index item exists and
+ * matches the criteria (name and index number).
+ */
+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 index, const struct fscrypt_str *name, int mod)
+{
+	struct btrfs_dir_item *di;
+	struct btrfs_key key;
+
+	key.objectid = dir;
+	key.type = BTRFS_DIR_INDEX_KEY;
+	key.offset = index;
+
+	di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
+				    name->len, mod);
+	if (di == ERR_PTR(-ENOENT))
+		return NULL;
+
+	return di;
+}
+
+struct btrfs_dir_item *
+btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
+			    u64 dirid, const struct fscrypt_str *name)
+{
+	struct btrfs_dir_item *di;
+	struct btrfs_key key;
+	int ret;
+
+	key.objectid = dirid;
+	key.type = BTRFS_DIR_INDEX_KEY;
+	key.offset = 0;
+
+	btrfs_for_each_slot(root, &key, &key, path, ret) {
+		if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
+			break;
+
+		di = btrfs_match_dir_item_name(root->fs_info, path,
+					       name->name, name->len);
+		if (di)
+			return di;
+	}
+	/* Adjust return code if the key was not found in the next leaf. */
+	if (ret > 0)
+		ret = 0;
+
+	return ERR_PTR(ret);
+}
+
+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)
+{
+	struct btrfs_key key;
+	struct btrfs_dir_item *di;
+
+	key.objectid = dir;
+	key.type = BTRFS_XATTR_ITEM_KEY;
+	key.offset = btrfs_name_hash(name, name_len);
+
+	di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
+	if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
+		return NULL;
+
+	return di;
+}
+
+/*
+ * 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_fs_info *fs_info,
+						 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);
+
+	total_len = btrfs_item_size(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(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(path, item_len - sub_item_len, 1);
+	}
+	return ret;
+}