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, 195 insertions, 0 deletions

diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
new file mode 100644
index 000000000..6f685f3c9
--- /dev/null
+++ b/fs/btrfs/extent_map.h
@@ -0,0 +1,195 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BTRFS_EXTENT_MAP_H
+#define BTRFS_EXTENT_MAP_H
+
+#include <linux/compiler_types.h>
+#include <linux/spinlock_types.h>
+#include <linux/rbtree.h>
+#include <linux/list.h>
+#include <linux/refcount.h>
+#include "fs.h"
+
+struct btrfs_inode;
+struct btrfs_fs_info;
+
+#define EXTENT_MAP_LAST_BYTE ((u64)-4)
+#define EXTENT_MAP_HOLE ((u64)-3)
+#define EXTENT_MAP_INLINE ((u64)-2)
+
+/* bits for the extent_map::flags field */
+enum {
+	/* this entry not yet on disk, don't free it */
+	ENUM_BIT(EXTENT_FLAG_PINNED),
+	ENUM_BIT(EXTENT_FLAG_COMPRESS_ZLIB),
+	ENUM_BIT(EXTENT_FLAG_COMPRESS_LZO),
+	ENUM_BIT(EXTENT_FLAG_COMPRESS_ZSTD),
+	/* pre-allocated extent */
+	ENUM_BIT(EXTENT_FLAG_PREALLOC),
+	/* Logging this extent */
+	ENUM_BIT(EXTENT_FLAG_LOGGING),
+	/* This em is merged from two or more physically adjacent ems */
+	ENUM_BIT(EXTENT_FLAG_MERGED),
+};
+
+/*
+ * This structure represents file extents and holes.
+ *
+ * Unlike on-disk file extent items, extent maps can be merged to save memory.
+ * This means members only match file extent items before any merging.
+ *
+ * Keep this structure as compact as possible, as we can have really large
+ * amounts of allocated extent maps at any time.
+ */
+struct extent_map {
+	struct rb_node rb_node;
+
+	/* All of these are in bytes. */
+
+	/* File offset matching the offset of a BTRFS_EXTENT_ITEM_KEY key. */
+	u64 start;
+
+	/*
+	 * Length of the file extent.
+	 *
+	 * For non-inlined file extents it's btrfs_file_extent_item::num_bytes.
+	 * For inline extents it's sectorsize, since inline data starts at
+	 * offsetof(struct btrfs_file_extent_item, disk_bytenr) thus
+	 * btrfs_file_extent_item::num_bytes is not valid.
+	 */
+	u64 len;
+
+	/*
+	 * The bytenr of the full on-disk extent.
+	 *
+	 * For regular extents it's btrfs_file_extent_item::disk_bytenr.
+	 * For holes it's EXTENT_MAP_HOLE and for inline extents it's
+	 * EXTENT_MAP_INLINE.
+	 */
+	u64 disk_bytenr;
+
+	/*
+	 * The full on-disk extent length, matching
+	 * btrfs_file_extent_item::disk_num_bytes.
+	 */
+	u64 disk_num_bytes;
+
+	/*
+	 * Offset inside the decompressed extent.
+	 *
+	 * For regular extents it's btrfs_file_extent_item::offset.
+	 * For holes and inline extents it's 0.
+	 */
+	u64 offset;
+
+	/*
+	 * The decompressed size of the whole on-disk extent, matching
+	 * btrfs_file_extent_item::ram_bytes.
+	 */
+	u64 ram_bytes;
+
+	/*
+	 * Generation of the extent map, for merged em it's the highest
+	 * generation of all merged ems.
+	 * For non-merged extents, it's from btrfs_file_extent_item::generation.
+	 */
+	u64 generation;
+	u32 flags;
+	refcount_t refs;
+	struct list_head list;
+};
+
+struct extent_map_tree {
+	struct rb_root root;
+	struct list_head modified_extents;
+	rwlock_t lock;
+};
+
+struct btrfs_inode;
+
+static inline void btrfs_extent_map_set_compression(struct extent_map *em,
+						    enum btrfs_compression_type type)
+{
+	if (type == BTRFS_COMPRESS_ZLIB)
+		em->flags |= EXTENT_FLAG_COMPRESS_ZLIB;
+	else if (type == BTRFS_COMPRESS_LZO)
+		em->flags |= EXTENT_FLAG_COMPRESS_LZO;
+	else if (type == BTRFS_COMPRESS_ZSTD)
+		em->flags |= EXTENT_FLAG_COMPRESS_ZSTD;
+}
+
+static inline enum btrfs_compression_type btrfs_extent_map_compression(
+						       const struct extent_map *em)
+{
+	if (em->flags & EXTENT_FLAG_COMPRESS_ZLIB)
+		return BTRFS_COMPRESS_ZLIB;
+
+	if (em->flags & EXTENT_FLAG_COMPRESS_LZO)
+		return BTRFS_COMPRESS_LZO;
+
+	if (em->flags & EXTENT_FLAG_COMPRESS_ZSTD)
+		return BTRFS_COMPRESS_ZSTD;
+
+	return BTRFS_COMPRESS_NONE;
+}
+
+/*
+ * More efficient way to determine if extent is compressed, instead of using
+ * 'extent_map_compression() != BTRFS_COMPRESS_NONE'.
+ */
+static inline bool btrfs_extent_map_is_compressed(const struct extent_map *em)
+{
+	return (em->flags & (EXTENT_FLAG_COMPRESS_ZLIB |
+			     EXTENT_FLAG_COMPRESS_LZO |
+			     EXTENT_FLAG_COMPRESS_ZSTD)) != 0;
+}
+
+static inline int btrfs_extent_map_in_tree(const struct extent_map *em)
+{
+	return !RB_EMPTY_NODE(&em->rb_node);
+}
+
+static inline u64 btrfs_extent_map_block_start(const struct extent_map *em)
+{
+	if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) {
+		if (btrfs_extent_map_is_compressed(em))
+			return em->disk_bytenr;
+		return em->disk_bytenr + em->offset;
+	}
+	return em->disk_bytenr;
+}
+
+static inline u64 btrfs_extent_map_end(const struct extent_map *em)
+{
+	if (em->start + em->len < em->start)
+		return (u64)-1;
+	return em->start + em->len;
+}
+
+void btrfs_extent_map_tree_init(struct extent_map_tree *tree);
+struct extent_map *btrfs_lookup_extent_mapping(struct extent_map_tree *tree,
+					       u64 start, u64 len);
+void btrfs_remove_extent_mapping(struct btrfs_inode *inode, struct extent_map *em);
+int btrfs_split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,
+			   u64 new_logical);
+
+struct extent_map *btrfs_alloc_extent_map(void);
+void btrfs_free_extent_map(struct extent_map *em);
+int __init btrfs_extent_map_init(void);
+void __cold btrfs_extent_map_exit(void);
+int btrfs_unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen);
+void btrfs_clear_em_logging(struct btrfs_inode *inode, struct extent_map *em);
+struct extent_map *btrfs_search_extent_mapping(struct extent_map_tree *tree,
+					       u64 start, u64 len);
+int btrfs_add_extent_mapping(struct btrfs_inode *inode,
+			     struct extent_map **em_in, u64 start, u64 len);
+void btrfs_drop_extent_map_range(struct btrfs_inode *inode,
+				 u64 start, u64 end,
+				 bool skip_pinned);
+int btrfs_replace_extent_map_range(struct btrfs_inode *inode,
+				   struct extent_map *new_em,
+				   bool modified);
+void btrfs_free_extent_maps(struct btrfs_fs_info *fs_info, long nr_to_scan);
+void btrfs_init_extent_map_shrinker_work(struct btrfs_fs_info *fs_info);
+
+#endif