Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 528 insertions, 0 deletions

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
new file mode 100644
index 000000000..2e4c3efbd
--- /dev/null
+++ b/fs/btrfs/root-tree.c
@@ -0,0 +1,528 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ */
+
+#include <linux/err.h>
+#include <linux/uuid.h>
+#include "ctree.h"
+#include "fs.h"
+#include "messages.h"
+#include "transaction.h"
+#include "disk-io.h"
+#include "qgroup.h"
+#include "space-info.h"
+#include "accessors.h"
+#include "root-tree.h"
+#include "orphan.h"
+
+/*
+ * Read a root item from the tree. In case we detect a root item smaller then
+ * sizeof(root_item), we know it's an old version of the root structure and
+ * initialize all new fields to zero. The same happens if we detect mismatching
+ * generation numbers as then we know the root was once mounted with an older
+ * kernel that was not aware of the root item structure change.
+ */
+static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
+				struct btrfs_root_item *item)
+{
+	u32 len;
+	bool need_reset = false;
+
+	len = btrfs_item_size(eb, slot);
+	read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
+			   min_t(u32, len, sizeof(*item)));
+	if (len < sizeof(*item))
+		need_reset = true;
+	if (!need_reset && btrfs_root_generation(item)
+		!= btrfs_root_generation_v2(item)) {
+		if (btrfs_root_generation_v2(item) != 0) {
+			btrfs_warn(eb->fs_info,
+					"mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.");
+		}
+		need_reset = true;
+	}
+	if (need_reset) {
+		/* Clear all members from generation_v2 onwards. */
+		memset_startat(item, 0, generation_v2);
+		generate_random_guid(item->uuid);
+	}
+}
+
+/*
+ * Lookup the root by the key.
+ *
+ * root: the root of the root tree
+ * search_key: the key to search
+ * path: the path we search
+ * root_item: the root item of the tree we look for
+ * root_key: the root key of the tree we look for
+ *
+ * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
+ * of the search key, just lookup the root with the highest offset for a
+ * given objectid.
+ *
+ * If we find something return 0, otherwise > 0, < 0 on error.
+ */
+int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key,
+		    struct btrfs_path *path, struct btrfs_root_item *root_item,
+		    struct btrfs_key *root_key)
+{
+	struct btrfs_key found_key;
+	struct extent_buffer *l;
+	int ret;
+	int slot;
+
+	ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
+	if (ret < 0)
+		return ret;
+
+	if (search_key->offset != -1ULL) {	/* the search key is exact */
+		if (ret > 0)
+			goto out;
+	} else {
+		/*
+		 * Key with offset -1 found, there would have to exist a root
+		 * with such id, but this is out of the valid range.
+		 */
+		if (unlikely(ret == 0)) {
+			ret = -EUCLEAN;
+			goto out;
+		}
+		if (path->slots[0] == 0)
+			goto out;
+		path->slots[0]--;
+		ret = 0;
+	}
+
+	l = path->nodes[0];
+	slot = path->slots[0];
+
+	btrfs_item_key_to_cpu(l, &found_key, slot);
+	if (found_key.objectid != search_key->objectid ||
+	    found_key.type != BTRFS_ROOT_ITEM_KEY) {
+		ret = 1;
+		goto out;
+	}
+
+	if (root_item)
+		btrfs_read_root_item(l, slot, root_item);
+	if (root_key)
+		memcpy(root_key, &found_key, sizeof(found_key));
+out:
+	btrfs_release_path(path);
+	return ret;
+}
+
+void btrfs_set_root_node(struct btrfs_root_item *item,
+			 struct extent_buffer *node)
+{
+	btrfs_set_root_bytenr(item, node->start);
+	btrfs_set_root_level(item, btrfs_header_level(node));
+	btrfs_set_root_generation(item, btrfs_header_generation(node));
+}
+
+/*
+ * copy the data in 'item' into the btree
+ */
+int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
+		      *root, struct btrfs_key *key, struct btrfs_root_item
+		      *item)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	BTRFS_PATH_AUTO_FREE(path);
+	struct extent_buffer *l;
+	int ret;
+	int slot;
+	unsigned long ptr;
+	u32 old_len;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	ret = btrfs_search_slot(trans, root, key, path, 0, 1);
+	if (ret < 0)
+		return ret;
+
+	if (unlikely(ret > 0)) {
+		btrfs_crit(fs_info,
+			   "unable to find root key " BTRFS_KEY_FMT " in tree %llu",
+			   BTRFS_KEY_FMT_VALUE(key), btrfs_root_id(root));
+		ret = -EUCLEAN;
+		btrfs_abort_transaction(trans, ret);
+		return ret;
+	}
+
+	l = path->nodes[0];
+	slot = path->slots[0];
+	ptr = btrfs_item_ptr_offset(l, slot);
+	old_len = btrfs_item_size(l, slot);
+
+	/*
+	 * If this is the first time we update the root item which originated
+	 * from an older kernel, we need to enlarge the item size to make room
+	 * for the added fields.
+	 */
+	if (old_len < sizeof(*item)) {
+		btrfs_release_path(path);
+		ret = btrfs_search_slot(trans, root, key, path,
+				-1, 1);
+		if (unlikely(ret < 0)) {
+			btrfs_abort_transaction(trans, ret);
+			return ret;
+		}
+
+		ret = btrfs_del_item(trans, root, path);
+		if (unlikely(ret < 0)) {
+			btrfs_abort_transaction(trans, ret);
+			return ret;
+		}
+		btrfs_release_path(path);
+		ret = btrfs_insert_empty_item(trans, root, path,
+				key, sizeof(*item));
+		if (unlikely(ret < 0)) {
+			btrfs_abort_transaction(trans, ret);
+			return ret;
+		}
+		l = path->nodes[0];
+		slot = path->slots[0];
+		ptr = btrfs_item_ptr_offset(l, slot);
+	}
+
+	/*
+	 * Update generation_v2 so at the next mount we know the new root
+	 * fields are valid.
+	 */
+	btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
+
+	write_extent_buffer(l, item, ptr, sizeof(*item));
+	return ret;
+}
+
+int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		      const struct btrfs_key *key, struct btrfs_root_item *item)
+{
+	/*
+	 * Make sure generation v1 and v2 match. See update_root for details.
+	 */
+	btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
+	return btrfs_insert_item(trans, root, key, item, sizeof(*item));
+}
+
+int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_root *tree_root = fs_info->tree_root;
+	struct extent_buffer *leaf;
+	BTRFS_PATH_AUTO_FREE(path);
+	struct btrfs_key key;
+	struct btrfs_root *root;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	key.objectid = BTRFS_ORPHAN_OBJECTID;
+	key.type = BTRFS_ORPHAN_ITEM_KEY;
+	key.offset = 0;
+
+	while (1) {
+		u64 root_objectid;
+		int ret;
+
+		ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+		if (ret < 0)
+			return ret;
+
+		leaf = path->nodes[0];
+		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(tree_root, path);
+			if (ret < 0)
+				return ret;
+			else if (ret > 0)
+				return 0;
+			leaf = path->nodes[0];
+		}
+
+		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+		btrfs_release_path(path);
+
+		if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
+		    key.type != BTRFS_ORPHAN_ITEM_KEY)
+			return 0;
+
+		root_objectid = key.offset;
+		key.offset++;
+
+		root = btrfs_get_fs_root(fs_info, root_objectid, false);
+		ret = PTR_ERR_OR_ZERO(root);
+		if (ret && ret != -ENOENT) {
+			return ret;
+		} else if (ret == -ENOENT) {
+			struct btrfs_trans_handle *trans;
+
+			trans = btrfs_join_transaction(tree_root);
+			if (IS_ERR(trans)) {
+				ret = PTR_ERR(trans);
+				btrfs_err(fs_info,
+			  "failed to join transaction to delete orphan item: %pe",
+					  ERR_PTR(ret));
+				return ret;
+			}
+			ret = btrfs_del_orphan_item(trans, tree_root, root_objectid);
+			btrfs_end_transaction(trans);
+			if (ret) {
+				btrfs_err(fs_info,
+				  "failed to delete root orphan item: %pe", ERR_PTR(ret));
+				return ret;
+			}
+			continue;
+		}
+
+		WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state));
+		if (btrfs_root_refs(&root->root_item) == 0) {
+			struct btrfs_key drop_key;
+
+			btrfs_disk_key_to_cpu(&drop_key, &root->root_item.drop_progress);
+			/*
+			 * If we have a non-zero drop_progress then we know we
+			 * made it partly through deleting this snapshot, and
+			 * thus we need to make sure we block any balance from
+			 * happening until this snapshot is completely dropped.
+			 */
+			if (drop_key.objectid != 0 || drop_key.type != 0 ||
+			    drop_key.offset != 0) {
+				set_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
+				set_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
+			}
+
+			set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
+			btrfs_add_dead_root(root);
+		}
+		btrfs_put_root(root);
+	}
+
+	return 0;
+}
+
+/* drop the root item for 'key' from the tree root */
+int btrfs_del_root(struct btrfs_trans_handle *trans,
+		   const struct btrfs_key *key)
+{
+	struct btrfs_root *root = trans->fs_info->tree_root;
+	BTRFS_PATH_AUTO_FREE(path);
+	int ret;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
+	if (ret < 0)
+		return ret;
+	if (unlikely(ret > 0))
+		/* The root must exist but we did not find it by the key. */
+		return -EUCLEAN;
+
+	return btrfs_del_item(trans, root, path);
+}
+
+int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
+		       u64 ref_id, u64 dirid, u64 *sequence,
+		       const struct fscrypt_str *name)
+{
+	struct btrfs_root *tree_root = trans->fs_info->tree_root;
+	BTRFS_PATH_AUTO_FREE(path);
+	struct btrfs_root_ref *ref;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	unsigned long ptr;
+	int ret;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	key.objectid = root_id;
+	key.type = BTRFS_ROOT_BACKREF_KEY;
+	key.offset = ref_id;
+again:
+	ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
+	if (ret < 0) {
+		return ret;
+	} else if (ret == 0) {
+		leaf = path->nodes[0];
+		ref = btrfs_item_ptr(leaf, path->slots[0],
+				     struct btrfs_root_ref);
+		ptr = (unsigned long)(ref + 1);
+		if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||
+		    (btrfs_root_ref_name_len(leaf, ref) != name->len) ||
+		    memcmp_extent_buffer(leaf, name->name, ptr, name->len))
+			return -ENOENT;
+
+		*sequence = btrfs_root_ref_sequence(leaf, ref);
+
+		ret = btrfs_del_item(trans, tree_root, path);
+		if (ret)
+			return ret;
+	} else {
+		return -ENOENT;
+	}
+
+	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+		btrfs_release_path(path);
+		key.objectid = ref_id;
+		key.type = BTRFS_ROOT_REF_KEY;
+		key.offset = root_id;
+		goto again;
+	}
+
+	return ret;
+}
+
+/*
+ * add a btrfs_root_ref item.  type is either BTRFS_ROOT_REF_KEY
+ * or BTRFS_ROOT_BACKREF_KEY.
+ *
+ * The dirid, sequence, name and name_len refer to the directory entry
+ * that is referencing the root.
+ *
+ * For a forward ref, the root_id is the id of the tree referencing
+ * the root and ref_id is the id of the subvol  or snapshot.
+ *
+ * For a back ref the root_id is the id of the subvol or snapshot and
+ * ref_id is the id of the tree referencing it.
+ *
+ * Will return 0, -ENOMEM, or anything from the CoW path
+ */
+int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
+		       u64 ref_id, u64 dirid, u64 sequence,
+		       const struct fscrypt_str *name)
+{
+	struct btrfs_root *tree_root = trans->fs_info->tree_root;
+	struct btrfs_key key;
+	int ret;
+	BTRFS_PATH_AUTO_FREE(path);
+	struct btrfs_root_ref *ref;
+	struct extent_buffer *leaf;
+	unsigned long ptr;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	key.objectid = root_id;
+	key.type = BTRFS_ROOT_BACKREF_KEY;
+	key.offset = ref_id;
+again:
+	ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
+				      sizeof(*ref) + name->len);
+	if (unlikely(ret)) {
+		btrfs_abort_transaction(trans, ret);
+		return ret;
+	}
+
+	leaf = path->nodes[0];
+	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
+	btrfs_set_root_ref_dirid(leaf, ref, dirid);
+	btrfs_set_root_ref_sequence(leaf, ref, sequence);
+	btrfs_set_root_ref_name_len(leaf, ref, name->len);
+	ptr = (unsigned long)(ref + 1);
+	write_extent_buffer(leaf, name->name, ptr, name->len);
+
+	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+		btrfs_release_path(path);
+		key.objectid = ref_id;
+		key.type = BTRFS_ROOT_REF_KEY;
+		key.offset = root_id;
+		goto again;
+	}
+
+	return 0;
+}
+
+/*
+ * Old btrfs forgets to init root_item->flags and root_item->byte_limit
+ * for subvolumes. To work around this problem, we steal a bit from
+ * root_item->inode_item->flags, and use it to indicate if those fields
+ * have been properly initialized.
+ */
+void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
+{
+	u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
+
+	if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
+		inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
+		btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
+		btrfs_set_root_flags(root_item, 0);
+		btrfs_set_root_limit(root_item, 0);
+	}
+}
+
+void btrfs_update_root_times(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *root)
+{
+	struct btrfs_root_item *item = &root->root_item;
+	struct timespec64 ct;
+
+	ktime_get_real_ts64(&ct);
+	spin_lock(&root->root_item_lock);
+	btrfs_set_root_ctransid(item, trans->transid);
+	btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
+	btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
+	spin_unlock(&root->root_item_lock);
+}
+
+/*
+ * Reserve space for subvolume operation.
+ *
+ * root: the root of the parent directory
+ * rsv: block reservation
+ * items: the number of items that we need do reservation
+ * use_global_rsv: allow fallback to the global block reservation
+ *
+ * This function is used to reserve the space for snapshot/subvolume
+ * creation and deletion. Those operations are different with the
+ * common file/directory operations, they change two fs/file trees
+ * and root tree, the number of items that the qgroup reserves is
+ * different with the free space reservation. So we can not use
+ * the space reservation mechanism in start_transaction().
+ */
+int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
+				     struct btrfs_block_rsv *rsv, int items,
+				     bool use_global_rsv)
+{
+	u64 qgroup_num_bytes = 0;
+	u64 num_bytes;
+	int ret;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+
+	if (btrfs_qgroup_enabled(fs_info)) {
+		/* One for parent inode, two for dir entries */
+		qgroup_num_bytes = 3 * fs_info->nodesize;
+		ret = btrfs_qgroup_reserve_meta_prealloc(root,
+							 qgroup_num_bytes, true,
+							 false);
+		if (ret)
+			return ret;
+	}
+
+	num_bytes = btrfs_calc_insert_metadata_size(fs_info, items);
+	rsv->space_info = btrfs_find_space_info(fs_info,
+					    BTRFS_BLOCK_GROUP_METADATA);
+	ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes,
+				  BTRFS_RESERVE_FLUSH_ALL);
+
+	if (ret == -ENOSPC && use_global_rsv)
+		ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
+
+	if (ret && qgroup_num_bytes)
+		btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
+
+	if (!ret) {
+		spin_lock(&rsv->lock);
+		rsv->qgroup_rsv_reserved += qgroup_num_bytes;
+		spin_unlock(&rsv->lock);
+	}
+	return ret;
+}