[PATCH 5.9 225/391] btrfs: tracepoints: output proper root owner for trace_find_free_extent()

From: Greg Kroah-Hartman
Date: Tue Nov 03 2020 - 15:47:54 EST


From: Qu Wenruo <wqu@xxxxxxxx>

commit 437490fed3b0c9ae21af8f70e0f338d34560842b upstream.

The current trace event always output result like this:

find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA)
find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA)
find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA)
find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA)
find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA)
find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA)

T's saying we're allocating data extent for EXTENT tree, which is not
even possible.

It's because we always use EXTENT tree as the owner for
trace_find_free_extent() without using the @root from
btrfs_reserve_extent().

This patch will change the parameter to use proper @root for
trace_find_free_extent():

Now it looks much better:

find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA)
find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=1(DATA)
find_free_extent: root=5(FS_TREE) len=4096 empty_size=0 flags=1(DATA)
find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA)
find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
find_free_extent: root=7(CSUM_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
find_free_extent: root=1(ROOT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)

Reported-by: Hans van Kranenburg <hans@xxxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # 5.4+
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/btrfs/extent-tree.c | 7 ++++---
include/trace/events/btrfs.h | 10 ++++++----
2 files changed, 10 insertions(+), 7 deletions(-)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3918,11 +3918,12 @@ static int prepare_allocation(struct btr
* |- Push harder to find free extents
* |- If not found, re-iterate all block groups
*/
-static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
+static noinline int find_free_extent(struct btrfs_root *root,
u64 ram_bytes, u64 num_bytes, u64 empty_size,
u64 hint_byte_orig, struct btrfs_key *ins,
u64 flags, int delalloc)
{
+ struct btrfs_fs_info *fs_info = root->fs_info;
int ret = 0;
int cache_block_group_error = 0;
struct btrfs_block_group *block_group = NULL;
@@ -3954,7 +3955,7 @@ static noinline int find_free_extent(str
ins->objectid = 0;
ins->offset = 0;

- trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
+ trace_find_free_extent(root, num_bytes, empty_size, flags);

space_info = btrfs_find_space_info(fs_info, flags);
if (!space_info) {
@@ -4203,7 +4204,7 @@ int btrfs_reserve_extent(struct btrfs_ro
flags = get_alloc_profile_by_root(root, is_data);
again:
WARN_ON(num_bytes < fs_info->sectorsize);
- ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
+ ret = find_free_extent(root, ram_bytes, num_bytes, empty_size,
hint_byte, ins, flags, delalloc);
if (!ret && !is_data) {
btrfs_dec_block_group_reservations(fs_info, ins->objectid);
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1176,25 +1176,27 @@ DEFINE_EVENT(btrfs__reserved_extent, bt

TRACE_EVENT(find_free_extent,

- TP_PROTO(const struct btrfs_fs_info *fs_info, u64 num_bytes,
+ TP_PROTO(const struct btrfs_root *root, u64 num_bytes,
u64 empty_size, u64 data),

- TP_ARGS(fs_info, num_bytes, empty_size, data),
+ TP_ARGS(root, num_bytes, empty_size, data),

TP_STRUCT__entry_btrfs(
+ __field( u64, root_objectid )
__field( u64, num_bytes )
__field( u64, empty_size )
__field( u64, data )
),

- TP_fast_assign_btrfs(fs_info,
+ TP_fast_assign_btrfs(root->fs_info,
+ __entry->root_objectid = root->root_key.objectid;
__entry->num_bytes = num_bytes;
__entry->empty_size = empty_size;
__entry->data = data;
),

TP_printk_btrfs("root=%llu(%s) len=%llu empty_size=%llu flags=%llu(%s)",
- show_root_type(BTRFS_EXTENT_TREE_OBJECTID),
+ show_root_type(__entry->root_objectid),
__entry->num_bytes, __entry->empty_size, __entry->data,
__print_flags((unsigned long)__entry->data, "|",
BTRFS_GROUP_FLAGS))