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, 1202 insertions, 0 deletions

diff --git a/fs/btrfs/tests/extent-map-tests.c b/fs/btrfs/tests/extent-map-tests.c
new file mode 100644
index 000000000..811f36d41
--- /dev/null
+++ b/fs/btrfs/tests/extent-map-tests.c
@@ -0,0 +1,1202 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Oracle.  All rights reserved.
+ */
+
+#include <linux/types.h>
+#include "btrfs-tests.h"
+#include "../ctree.h"
+#include "../btrfs_inode.h"
+#include "../volumes.h"
+#include "../disk-io.h"
+#include "../block-group.h"
+
+static int free_extent_map_tree(struct btrfs_inode *inode)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	struct rb_node *node;
+	int ret = 0;
+
+	write_lock(&em_tree->lock);
+	while (!RB_EMPTY_ROOT(&em_tree->root)) {
+		node = rb_first(&em_tree->root);
+		em = rb_entry(node, struct extent_map, rb_node);
+		btrfs_remove_extent_mapping(inode, em);
+
+#ifdef CONFIG_BTRFS_DEBUG
+		if (refcount_read(&em->refs) != 1) {
+			ret = -EINVAL;
+			test_err(
+"em leak: em (start %llu len %llu disk_bytenr %llu disk_num_bytes %llu offset %llu) refs %d",
+				 em->start, em->len, em->disk_bytenr,
+				 em->disk_num_bytes, em->offset,
+				 refcount_read(&em->refs));
+
+			refcount_set(&em->refs, 1);
+		}
+#endif
+		btrfs_free_extent_map(em);
+	}
+	write_unlock(&em_tree->lock);
+
+	return ret;
+}
+
+/*
+ * Test scenario:
+ *
+ * Suppose that no extent map has been loaded into memory yet, there is a file
+ * extent [0, 16K), followed by another file extent [16K, 20K), two dio reads
+ * are entering btrfs_get_extent() concurrently, t1 is reading [8K, 16K), t2 is
+ * reading [0, 8K)
+ *
+ *     t1                            t2
+ *  btrfs_get_extent()              btrfs_get_extent()
+ *    -> lookup_extent_mapping()      ->lookup_extent_mapping()
+ *    -> add_extent_mapping(0, 16K)
+ *    -> return em
+ *                                    ->add_extent_mapping(0, 16K)
+ *                                    -> #handle -EEXIST
+ */
+static int test_case_1(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	u64 start = 0;
+	u64 len = SZ_8K;
+	int ret;
+	int ret2;
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		return -ENOMEM;
+	}
+
+	/* Add [0, 16K) */
+	em->start = 0;
+	em->len = SZ_16K;
+	em->disk_bytenr = 0;
+	em->disk_num_bytes = SZ_16K;
+	em->ram_bytes = SZ_16K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("cannot add extent range [0, 16K)");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	/* Add [16K, 20K) following [0, 16K)  */
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	em->start = SZ_16K;
+	em->len = SZ_4K;
+	em->disk_bytenr = SZ_32K; /* avoid merging */
+	em->disk_num_bytes = SZ_4K;
+	em->ram_bytes = SZ_4K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("cannot add extent range [16K, 20K)");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* Add [0, 8K), should return [0, 16K) instead. */
+	em->start = start;
+	em->len = len;
+	em->disk_bytenr = start;
+	em->disk_num_bytes = len;
+	em->ram_bytes = len;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret) {
+		test_err("case1 [%llu %llu]: ret %d", start, start + len, ret);
+		goto out;
+	}
+	if (!em) {
+		test_err("case1 [%llu %llu]: no extent map returned",
+			 start, start + len);
+		ret = -ENOENT;
+		goto out;
+	}
+	if (em->start != 0 || btrfs_extent_map_end(em) != SZ_16K ||
+	    em->disk_bytenr != 0 || em->disk_num_bytes != SZ_16K) {
+		test_err(
+"case1 [%llu %llu]: ret %d return a wrong em (start %llu len %llu disk_bytenr %llu disk_num_bytes %llu",
+			 start, start + len, ret, em->start, em->len,
+			 em->disk_bytenr, em->disk_num_bytes);
+		ret = -EINVAL;
+	}
+	btrfs_free_extent_map(em);
+out:
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+/*
+ * Test scenario:
+ *
+ * Reading the inline ending up with EEXIST, ie. read an inline
+ * extent and discard page cache and read it again.
+ */
+static int test_case_2(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	int ret;
+	int ret2;
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		return -ENOMEM;
+	}
+
+	/*
+	 * Add [0, 1K) which is inlined. And the extent map length must
+	 * be one block.
+	 */
+	em->start = 0;
+	em->len = SZ_4K;
+	em->disk_bytenr = EXTENT_MAP_INLINE;
+	em->disk_num_bytes = 0;
+	em->ram_bytes = SZ_1K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("cannot add extent range [0, 1K)");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	/* Add [4K, 8K) following [0, 1K)  */
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	em->start = SZ_4K;
+	em->len = SZ_4K;
+	em->disk_bytenr = SZ_4K;
+	em->disk_num_bytes = SZ_4K;
+	em->ram_bytes = SZ_4K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("cannot add extent range [4K, 8K)");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* Add [0, 1K) */
+	em->start = 0;
+	em->len = SZ_4K;
+	em->disk_bytenr = EXTENT_MAP_INLINE;
+	em->disk_num_bytes = 0;
+	em->ram_bytes = SZ_1K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret) {
+		test_err("case2 [0 1K]: ret %d", ret);
+		goto out;
+	}
+	if (!em) {
+		test_err("case2 [0 1K]: no extent map returned");
+		ret = -ENOENT;
+		goto out;
+	}
+	if (em->start != 0 || btrfs_extent_map_end(em) != SZ_4K ||
+	    em->disk_bytenr != EXTENT_MAP_INLINE) {
+		test_err(
+"case2 [0 1K]: ret %d return a wrong em (start %llu len %llu disk_bytenr %llu",
+			 ret, em->start, em->len, em->disk_bytenr);
+		ret = -EINVAL;
+	}
+	btrfs_free_extent_map(em);
+out:
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+static int __test_case_3(struct btrfs_fs_info *fs_info,
+			 struct btrfs_inode *inode, u64 start)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	u64 len = SZ_4K;
+	int ret;
+	int ret2;
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		return -ENOMEM;
+	}
+
+	/* Add [4K, 8K) */
+	em->start = SZ_4K;
+	em->len = SZ_4K;
+	em->disk_bytenr = SZ_4K;
+	em->disk_num_bytes = SZ_4K;
+	em->ram_bytes = SZ_4K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("cannot add extent range [4K, 8K)");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* Add [0, 16K) */
+	em->start = 0;
+	em->len = SZ_16K;
+	em->disk_bytenr = 0;
+	em->disk_num_bytes = SZ_16K;
+	em->ram_bytes = SZ_16K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, start, len);
+	write_unlock(&em_tree->lock);
+	if (ret) {
+		test_err("case3 [%llu %llu): ret %d",
+			 start, start + len, ret);
+		goto out;
+	}
+	if (!em) {
+		test_err("case3 [%llu %llu): no extent map returned",
+			 start, start + len);
+		ret = -ENOENT;
+		goto out;
+	}
+	/*
+	 * Since bytes within em are contiguous, em->block_start is identical to
+	 * em->start.
+	 */
+	if (start < em->start || start + len > btrfs_extent_map_end(em) ||
+	    em->start != btrfs_extent_map_block_start(em)) {
+		test_err(
+"case3 [%llu %llu): ret %d em (start %llu len %llu disk_bytenr %llu block_len %llu)",
+			 start, start + len, ret, em->start, em->len,
+			 em->disk_bytenr, em->disk_num_bytes);
+		ret = -EINVAL;
+	}
+	btrfs_free_extent_map(em);
+out:
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+/*
+ * Test scenario:
+ *
+ * Suppose that no extent map has been loaded into memory yet.
+ * There is a file extent [0, 16K), two jobs are running concurrently
+ * against it, t1 is buffered writing to [4K, 8K) and t2 is doing dio
+ * read from [0, 4K) or [8K, 12K) or [12K, 16K).
+ *
+ * t1 goes ahead of t2 and adds em [4K, 8K) into tree.
+ *
+ *         t1                       t2
+ *  cow_file_range()	     btrfs_get_extent()
+ *                            -> lookup_extent_mapping()
+ *   -> add_extent_mapping()
+ *                            -> add_extent_mapping()
+ */
+static int test_case_3(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	int ret;
+
+	ret = __test_case_3(fs_info, inode, 0);
+	if (ret)
+		return ret;
+	ret = __test_case_3(fs_info, inode, SZ_8K);
+	if (ret)
+		return ret;
+	ret = __test_case_3(fs_info, inode, (12 * SZ_1K));
+
+	return ret;
+}
+
+static int __test_case_4(struct btrfs_fs_info *fs_info,
+			 struct btrfs_inode *inode, u64 start)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	u64 len = SZ_4K;
+	int ret;
+	int ret2;
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		return -ENOMEM;
+	}
+
+	/* Add [0K, 8K) */
+	em->start = 0;
+	em->len = SZ_8K;
+	em->disk_bytenr = 0;
+	em->disk_num_bytes = SZ_8K;
+	em->ram_bytes = SZ_8K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("cannot add extent range [0, 8K)");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* Add [8K, 32K) */
+	em->start = SZ_8K;
+	em->len = 24 * SZ_1K;
+	em->disk_bytenr = SZ_16K; /* avoid merging */
+	em->disk_num_bytes = 24 * SZ_1K;
+	em->ram_bytes = 24 * SZ_1K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("cannot add extent range [8K, 32K)");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+	/* Add [0K, 32K) */
+	em->start = 0;
+	em->len = SZ_32K;
+	em->disk_bytenr = 0;
+	em->disk_num_bytes = SZ_32K;
+	em->ram_bytes = SZ_32K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, start, len);
+	write_unlock(&em_tree->lock);
+	if (ret) {
+		test_err("case4 [%llu %llu): ret %d",
+			 start, start + len, ret);
+		goto out;
+	}
+	if (!em) {
+		test_err("case4 [%llu %llu): no extent map returned",
+			 start, start + len);
+		ret = -ENOENT;
+		goto out;
+	}
+	if (start < em->start || start + len > btrfs_extent_map_end(em)) {
+		test_err(
+"case4 [%llu %llu): ret %d, added wrong em (start %llu len %llu disk_bytenr %llu disk_num_bytes %llu)",
+			 start, start + len, ret, em->start, em->len,
+			 em->disk_bytenr, em->disk_num_bytes);
+		ret = -EINVAL;
+	}
+	btrfs_free_extent_map(em);
+out:
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+/*
+ * Test scenario:
+ *
+ * Suppose that no extent map has been loaded into memory yet.
+ * There is a file extent [0, 32K), two jobs are running concurrently
+ * against it, t1 is doing dio write to [8K, 32K) and t2 is doing dio
+ * read from [0, 4K) or [4K, 8K).
+ *
+ * t1 goes ahead of t2 and splits em [0, 32K) to em [0K, 8K) and [8K 32K).
+ *
+ *         t1                                t2
+ *  btrfs_get_blocks_direct()	       btrfs_get_blocks_direct()
+ *   -> btrfs_get_extent()              -> btrfs_get_extent()
+ *       -> lookup_extent_mapping()
+ *       -> add_extent_mapping()            -> lookup_extent_mapping()
+ *          # load [0, 32K)
+ *   -> btrfs_new_extent_direct()
+ *       -> btrfs_drop_extent_cache()
+ *          # split [0, 32K)
+ *       -> add_extent_mapping()
+ *          # add [8K, 32K)
+ *                                          -> add_extent_mapping()
+ *                                             # handle -EEXIST when adding
+ *                                             # [0, 32K)
+ */
+static int test_case_4(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	int ret;
+
+	ret = __test_case_4(fs_info, inode, 0);
+	if (ret)
+		return ret;
+	ret = __test_case_4(fs_info, inode, SZ_4K);
+
+	return ret;
+}
+
+static int add_compressed_extent(struct btrfs_inode *inode,
+				 u64 start, u64 len, u64 block_start)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	int ret;
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		return -ENOMEM;
+	}
+
+	em->start = start;
+	em->len = len;
+	em->disk_bytenr = block_start;
+	em->disk_num_bytes = SZ_4K;
+	em->ram_bytes = len;
+	em->flags |= EXTENT_FLAG_COMPRESS_ZLIB;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	btrfs_free_extent_map(em);
+	if (ret < 0) {
+		test_err("cannot add extent map [%llu, %llu)", start, start + len);
+		return ret;
+	}
+
+	return 0;
+}
+
+struct extent_range {
+	u64 start;
+	u64 len;
+};
+
+/* The valid states of the tree after every drop, as described below. */
+struct extent_range valid_ranges[][7] = {
+	{
+	  { .start = 0,			.len = SZ_8K },		/* [0, 8K) */
+	  { .start = SZ_4K * 3,		.len = SZ_4K * 3},	/* [12k, 24k) */
+	  { .start = SZ_4K * 6,		.len = SZ_4K * 3},	/* [24k, 36k) */
+	  { .start = SZ_32K + SZ_4K,	.len = SZ_4K},		/* [36k, 40k) */
+	  { .start = SZ_4K * 10,	.len = SZ_4K * 6},	/* [40k, 64k) */
+	},
+	{
+	  { .start = 0,			.len = SZ_8K },		/* [0, 8K) */
+	  { .start = SZ_4K * 5,		.len = SZ_4K},		/* [20k, 24k) */
+	  { .start = SZ_4K * 6,		.len = SZ_4K * 3},	/* [24k, 36k) */
+	  { .start = SZ_32K + SZ_4K,	.len = SZ_4K},		/* [36k, 40k) */
+	  { .start = SZ_4K * 10,	.len = SZ_4K * 6},	/* [40k, 64k) */
+	},
+	{
+	  { .start = 0,			.len = SZ_8K },		/* [0, 8K) */
+	  { .start = SZ_4K * 5,		.len = SZ_4K},		/* [20k, 24k) */
+	  { .start = SZ_4K * 6,		.len = SZ_4K},		/* [24k, 28k) */
+	  { .start = SZ_32K,		.len = SZ_4K},		/* [32k, 36k) */
+	  { .start = SZ_32K + SZ_4K,	.len = SZ_4K},		/* [36k, 40k) */
+	  { .start = SZ_4K * 10,	.len = SZ_4K * 6},	/* [40k, 64k) */
+	},
+	{
+	  { .start = 0,			.len = SZ_8K},		/* [0, 8K) */
+	  { .start = SZ_4K * 5,		.len = SZ_4K},		/* [20k, 24k) */
+	  { .start = SZ_4K * 6,		.len = SZ_4K},		/* [24k, 28k) */
+	}
+};
+
+static int validate_range(struct extent_map_tree *em_tree, int index)
+{
+	struct rb_node *n;
+	int i;
+
+	for (i = 0, n = rb_first(&em_tree->root);
+	     valid_ranges[index][i].len && n;
+	     i++, n = rb_next(n)) {
+		struct extent_map *entry = rb_entry(n, struct extent_map, rb_node);
+
+		if (entry->start != valid_ranges[index][i].start) {
+			test_err("mapping has start %llu expected %llu",
+				 entry->start, valid_ranges[index][i].start);
+			return -EINVAL;
+		}
+
+		if (entry->len != valid_ranges[index][i].len) {
+			test_err("mapping has len %llu expected %llu",
+				 entry->len, valid_ranges[index][i].len);
+			return -EINVAL;
+		}
+	}
+
+	/*
+	 * We exited because we don't have any more entries in the extent_map
+	 * but we still expect more valid entries.
+	 */
+	if (valid_ranges[index][i].len) {
+		test_err("missing an entry");
+		return -EINVAL;
+	}
+
+	/* We exited the loop but still have entries in the extent map. */
+	if (n) {
+		test_err("we have a left over entry in the extent map we didn't expect");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Test scenario:
+ *
+ * Test the various edge cases of btrfs_drop_extent_map_range, create the
+ * following ranges
+ *
+ * [0, 12k)[12k, 24k)[24k, 36k)[36k, 40k)[40k,64k)
+ *
+ * And then we'll drop:
+ *
+ * [8k, 12k) - test the single front split
+ * [12k, 20k) - test the single back split
+ * [28k, 32k) - test the double split
+ * [32k, 64k) - test whole em dropping
+ *
+ * They'll have the EXTENT_FLAG_COMPRESSED flag set to keep the em tree from
+ * merging the em's.
+ */
+static int test_case_5(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	u64 start, end;
+	int ret;
+	int ret2;
+
+	test_msg("Running btrfs_drop_extent_map_range tests");
+
+	/* [0, 12k) */
+	ret = add_compressed_extent(inode, 0, SZ_4K * 3, 0);
+	if (ret) {
+		test_err("cannot add extent range [0, 12K)");
+		goto out;
+	}
+
+	/* [12k, 24k) */
+	ret = add_compressed_extent(inode, SZ_4K * 3, SZ_4K * 3, SZ_4K);
+	if (ret) {
+		test_err("cannot add extent range [12k, 24k)");
+		goto out;
+	}
+
+	/* [24k, 36k) */
+	ret = add_compressed_extent(inode, SZ_4K * 6, SZ_4K * 3, SZ_8K);
+	if (ret) {
+		test_err("cannot add extent range [12k, 24k)");
+		goto out;
+	}
+
+	/* [36k, 40k) */
+	ret = add_compressed_extent(inode, SZ_32K + SZ_4K, SZ_4K, SZ_4K * 3);
+	if (ret) {
+		test_err("cannot add extent range [12k, 24k)");
+		goto out;
+	}
+
+	/* [40k, 64k) */
+	ret = add_compressed_extent(inode, SZ_4K * 10, SZ_4K * 6, SZ_16K);
+	if (ret) {
+		test_err("cannot add extent range [12k, 24k)");
+		goto out;
+	}
+
+	/* Drop [8k, 12k) */
+	start = SZ_8K;
+	end = (3 * SZ_4K) - 1;
+	btrfs_drop_extent_map_range(inode, start, end, false);
+	ret = validate_range(&inode->extent_tree, 0);
+	if (ret)
+		goto out;
+
+	/* Drop [12k, 20k) */
+	start = SZ_4K * 3;
+	end = SZ_16K + SZ_4K - 1;
+	btrfs_drop_extent_map_range(inode, start, end, false);
+	ret = validate_range(&inode->extent_tree, 1);
+	if (ret)
+		goto out;
+
+	/* Drop [28k, 32k) */
+	start = SZ_32K - SZ_4K;
+	end = SZ_32K - 1;
+	btrfs_drop_extent_map_range(inode, start, end, false);
+	ret = validate_range(&inode->extent_tree, 2);
+	if (ret)
+		goto out;
+
+	/* Drop [32k, 64k) */
+	start = SZ_32K;
+	end = SZ_64K - 1;
+	btrfs_drop_extent_map_range(inode, start, end, false);
+	ret = validate_range(&inode->extent_tree, 3);
+	if (ret)
+		goto out;
+out:
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+/*
+ * Test the btrfs_add_extent_mapping helper which will attempt to create an em
+ * for areas between two existing ems.  Validate it doesn't do this when there
+ * are two unmerged em's side by side.
+ */
+static int test_case_6(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em = NULL;
+	int ret;
+	int ret2;
+
+	ret = add_compressed_extent(inode, 0, SZ_4K, 0);
+	if (ret)
+		goto out;
+
+	ret = add_compressed_extent(inode, SZ_4K, SZ_4K, 0);
+	if (ret)
+		goto out;
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	em->start = SZ_4K;
+	em->len = SZ_4K;
+	em->disk_bytenr = SZ_16K;
+	em->disk_num_bytes = SZ_16K;
+	em->ram_bytes = SZ_16K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, 0, SZ_8K);
+	write_unlock(&em_tree->lock);
+
+	if (ret != 0) {
+		test_err("got an error when adding our em: %d", ret);
+		goto out;
+	}
+
+	ret = -EINVAL;
+	if (em->start != 0) {
+		test_err("unexpected em->start at %llu, wanted 0", em->start);
+		goto out;
+	}
+	if (em->len != SZ_4K) {
+		test_err("unexpected em->len %llu, expected 4K", em->len);
+		goto out;
+	}
+	ret = 0;
+out:
+	btrfs_free_extent_map(em);
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+/*
+ * Regression test for btrfs_drop_extent_map_range.  Calling with skip_pinned ==
+ * true would mess up the start/end calculations and subsequent splits would be
+ * incorrect.
+ */
+static int test_case_7(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	int ret;
+	int ret2;
+
+	test_msg("Running btrfs_drop_extent_cache with pinned");
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		return -ENOMEM;
+	}
+
+	/* [0, 16K), pinned */
+	em->start = 0;
+	em->len = SZ_16K;
+	em->disk_bytenr = 0;
+	em->disk_num_bytes = SZ_4K;
+	em->ram_bytes = SZ_16K;
+	em->flags |= (EXTENT_FLAG_PINNED | EXTENT_FLAG_COMPRESS_ZLIB);
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("couldn't add extent map");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* [32K, 48K), not pinned */
+	em->start = SZ_32K;
+	em->len = SZ_16K;
+	em->disk_bytenr = SZ_32K;
+	em->disk_num_bytes = SZ_16K;
+	em->ram_bytes = SZ_16K;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	if (ret < 0) {
+		test_err("couldn't add extent map");
+		goto out;
+	}
+	btrfs_free_extent_map(em);
+
+	/*
+	 * Drop [0, 36K) This should skip the [0, 4K) extent and then split the
+	 * [32K, 48K) extent.
+	 */
+	btrfs_drop_extent_map_range(inode, 0, (36 * SZ_1K) - 1, true);
+
+	/* Make sure our extent maps look sane. */
+	ret = -EINVAL;
+
+	em = btrfs_lookup_extent_mapping(em_tree, 0, SZ_16K);
+	if (!em) {
+		test_err("didn't find an em at 0 as expected");
+		goto out;
+	}
+
+	if (em->start != 0) {
+		test_err("em->start is %llu, expected 0", em->start);
+		goto out;
+	}
+
+	if (em->len != SZ_16K) {
+		test_err("em->len is %llu, expected 16K", em->len);
+		goto out;
+	}
+
+	btrfs_free_extent_map(em);
+
+	read_lock(&em_tree->lock);
+	em = btrfs_lookup_extent_mapping(em_tree, SZ_16K, SZ_16K);
+	read_unlock(&em_tree->lock);
+	if (em) {
+		test_err("found an em when we weren't expecting one");
+		goto out;
+	}
+
+	read_lock(&em_tree->lock);
+	em = btrfs_lookup_extent_mapping(em_tree, SZ_32K, SZ_16K);
+	read_unlock(&em_tree->lock);
+	if (!em) {
+		test_err("didn't find an em at 32K as expected");
+		goto out;
+	}
+
+	if (em->start != (36 * SZ_1K)) {
+		test_err("em->start is %llu, expected 36K", em->start);
+		goto out;
+	}
+
+	if (em->len != (12 * SZ_1K)) {
+		test_err("em->len is %llu, expected 12K", em->len);
+		goto out;
+	}
+
+	if (btrfs_extent_map_block_start(em) != SZ_32K + SZ_4K) {
+		test_err("em->block_start is %llu, expected 36K",
+			 btrfs_extent_map_block_start(em));
+		goto out;
+	}
+
+	btrfs_free_extent_map(em);
+
+	read_lock(&em_tree->lock);
+	em = btrfs_lookup_extent_mapping(em_tree, 48 * SZ_1K, (u64)-1);
+	read_unlock(&em_tree->lock);
+	if (em) {
+		test_err("found an unexpected em above 48K");
+		goto out;
+	}
+
+	ret = 0;
+out:
+	btrfs_free_extent_map(em);
+	/* Unpin our extent to prevent warning when removing it below. */
+	ret2 = btrfs_unpin_extent_cache(inode, 0, SZ_16K, 0);
+	if (ret == 0)
+		ret = ret2;
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+/*
+ * Test a regression for compressed extent map adjustment when we attempt to
+ * add an extent map that is partially overlapped by another existing extent
+ * map. The resulting extent map offset was left unchanged despite having
+ * incremented its start offset.
+ */
+static int test_case_8(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
+{
+	struct extent_map_tree *em_tree = &inode->extent_tree;
+	struct extent_map *em;
+	int ret;
+	int ret2;
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		return -ENOMEM;
+	}
+
+	/* Compressed extent for the file range [120K, 128K). */
+	em->start = SZ_1K * 120;
+	em->len = SZ_8K;
+	em->disk_num_bytes = SZ_4K;
+	em->ram_bytes = SZ_8K;
+	em->flags |= EXTENT_FLAG_COMPRESS_ZLIB;
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
+	write_unlock(&em_tree->lock);
+	btrfs_free_extent_map(em);
+	if (ret < 0) {
+		test_err("couldn't add extent map for range [120K, 128K)");
+		goto out;
+	}
+
+	em = btrfs_alloc_extent_map();
+	if (!em) {
+		test_std_err(TEST_ALLOC_EXTENT_MAP);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Compressed extent for the file range [108K, 144K), which overlaps
+	 * with the [120K, 128K) we previously inserted.
+	 */
+	em->start = SZ_1K * 108;
+	em->len = SZ_1K * 36;
+	em->disk_num_bytes = SZ_4K;
+	em->ram_bytes = SZ_1K * 36;
+	em->flags |= EXTENT_FLAG_COMPRESS_ZLIB;
+
+	/*
+	 * Try to add the extent map but with a search range of [140K, 144K),
+	 * this should succeed and adjust the extent map to the range
+	 * [128K, 144K), with a length of 16K and an offset of 20K.
+	 *
+	 * This simulates a scenario where in the subvolume tree of an inode we
+	 * have a compressed file extent item for the range [108K, 144K) and we
+	 * have an overlapping compressed extent map for the range [120K, 128K),
+	 * which was created by an encoded write, but its ordered extent was not
+	 * yet completed, so the subvolume tree doesn't have yet the file extent
+	 * item for that range - we only have the extent map in the inode's
+	 * extent map tree.
+	 */
+	write_lock(&em_tree->lock);
+	ret = btrfs_add_extent_mapping(inode, &em, SZ_1K * 140, SZ_4K);
+	write_unlock(&em_tree->lock);
+	btrfs_free_extent_map(em);
+	if (ret < 0) {
+		test_err("couldn't add extent map for range [108K, 144K)");
+		goto out;
+	}
+
+	if (em->start != SZ_128K) {
+		test_err("unexpected extent map start %llu (should be 128K)", em->start);
+		ret = -EINVAL;
+		goto out;
+	}
+	if (em->len != SZ_16K) {
+		test_err("unexpected extent map length %llu (should be 16K)", em->len);
+		ret = -EINVAL;
+		goto out;
+	}
+	if (em->offset != SZ_1K * 20) {
+		test_err("unexpected extent map offset %llu (should be 20K)", em->offset);
+		ret = -EINVAL;
+		goto out;
+	}
+out:
+	ret2 = free_extent_map_tree(inode);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
+}
+
+struct rmap_test_vector {
+	u64 raid_type;
+	u64 physical_start;
+	u64 data_stripe_size;
+	u64 num_data_stripes;
+	u64 num_stripes;
+	/* Assume we won't have more than 5 physical stripes */
+	u64 data_stripe_phys_start[5];
+	bool expected_mapped_addr;
+	/* Physical to logical addresses */
+	u64 mapped_logical[5];
+};
+
+static int test_rmap_block(struct btrfs_fs_info *fs_info,
+			   struct rmap_test_vector *test)
+{
+	struct btrfs_chunk_map *map;
+	u64 AUTO_KFREE(logical);
+	int i, out_ndaddrs, out_stripe_len;
+	int ret;
+
+	map = btrfs_alloc_chunk_map(test->num_stripes, GFP_KERNEL);
+	if (!map) {
+		test_std_err(TEST_ALLOC_CHUNK_MAP);
+		return -ENOMEM;
+	}
+
+	/* Start at 4GiB logical address */
+	map->start = SZ_4G;
+	map->chunk_len = test->data_stripe_size * test->num_data_stripes;
+	map->stripe_size = test->data_stripe_size;
+	map->num_stripes = test->num_stripes;
+	map->type = test->raid_type;
+
+	for (i = 0; i < map->num_stripes; i++) {
+		struct btrfs_device *dev = btrfs_alloc_dummy_device(fs_info);
+
+		if (IS_ERR(dev)) {
+			test_err("cannot allocate device");
+			ret = PTR_ERR(dev);
+			goto out;
+		}
+		map->stripes[i].dev = dev;
+		map->stripes[i].physical = test->data_stripe_phys_start[i];
+	}
+
+	ret = btrfs_add_chunk_map(fs_info, map);
+	if (ret) {
+		test_err("error adding chunk map to mapping tree");
+		btrfs_free_chunk_map(map);
+		return ret;
+	}
+
+	ret = btrfs_rmap_block(fs_info, map->start, btrfs_sb_offset(1),
+			       &logical, &out_ndaddrs, &out_stripe_len);
+	if (ret || (out_ndaddrs == 0 && test->expected_mapped_addr)) {
+		test_err("didn't rmap anything but expected %d",
+			 test->expected_mapped_addr);
+		goto out;
+	}
+
+	if (out_stripe_len != BTRFS_STRIPE_LEN) {
+		test_err("calculated stripe length doesn't match");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (out_ndaddrs != test->expected_mapped_addr) {
+		for (i = 0; i < out_ndaddrs; i++)
+			test_msg("mapped %llu", logical[i]);
+		test_err("unexpected number of mapped addresses: %d", out_ndaddrs);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	for (i = 0; i < out_ndaddrs; i++) {
+		if (logical[i] != test->mapped_logical[i]) {
+			test_err("unexpected logical address mapped");
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	ret = 0;
+out:
+	btrfs_remove_chunk_map(fs_info, map);
+	return ret;
+}
+
+int btrfs_test_extent_map(void)
+{
+	struct btrfs_fs_info *fs_info = NULL;
+	struct inode *inode;
+	struct btrfs_root *root = NULL;
+	int ret = 0, i;
+	struct rmap_test_vector rmap_tests[] = {
+		{
+			/*
+			 * Test a chunk with 2 data stripes one of which
+			 * intersects the physical address of the super block
+			 * is correctly recognized.
+			 */
+			.raid_type = BTRFS_BLOCK_GROUP_RAID1,
+			.physical_start = SZ_64M - SZ_4M,
+			.data_stripe_size = SZ_256M,
+			.num_data_stripes = 2,
+			.num_stripes = 2,
+			.data_stripe_phys_start =
+				{SZ_64M - SZ_4M, SZ_64M - SZ_4M + SZ_256M},
+			.expected_mapped_addr = true,
+			.mapped_logical= {SZ_4G + SZ_4M}
+		},
+		{
+			/*
+			 * Test that out-of-range physical addresses are
+			 * ignored
+			 */
+
+			 /* SINGLE chunk type */
+			.raid_type = 0,
+			.physical_start = SZ_4G,
+			.data_stripe_size = SZ_256M,
+			.num_data_stripes = 1,
+			.num_stripes = 1,
+			.data_stripe_phys_start = {SZ_256M},
+			.expected_mapped_addr = false,
+			.mapped_logical = {0}
+		}
+	};
+
+	test_msg("running extent_map tests");
+
+	/*
+	 * Note: the fs_info is not set up completely, we only need
+	 * fs_info::fsid for the tracepoint.
+	 *
+	 * And all the immediate numbers are based on 4K blocksize,
+	 * thus we have to use 4K as sectorsize no matter the page size.
+	 */
+	fs_info = btrfs_alloc_dummy_fs_info(SZ_4K, SZ_4K);
+	if (!fs_info) {
+		test_std_err(TEST_ALLOC_FS_INFO);
+		return -ENOMEM;
+	}
+
+	inode = btrfs_new_test_inode();
+	if (!inode) {
+		test_std_err(TEST_ALLOC_INODE);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	root = btrfs_alloc_dummy_root(fs_info);
+	if (IS_ERR(root)) {
+		test_std_err(TEST_ALLOC_ROOT);
+		ret = PTR_ERR(root);
+		root = NULL;
+		goto out;
+	}
+
+	BTRFS_I(inode)->root = root;
+
+	ret = test_case_1(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+	ret = test_case_2(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+	ret = test_case_3(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+	ret = test_case_4(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+	ret = test_case_5(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+	ret = test_case_6(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+	ret = test_case_7(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+	ret = test_case_8(fs_info, BTRFS_I(inode));
+	if (ret)
+		goto out;
+
+	test_msg("running rmap tests");
+	for (i = 0; i < ARRAY_SIZE(rmap_tests); i++) {
+		ret = test_rmap_block(fs_info, &rmap_tests[i]);
+		if (ret)
+			goto out;
+	}
+
+out:
+	iput(inode);
+	btrfs_free_dummy_root(root);
+	btrfs_free_dummy_fs_info(fs_info);
+
+	return ret;
+}