btrfs: tracepoints: output proper root owner for trace_find_free_extent()

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@knorrie.org>
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 780b9c9..dbff61d 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3918,11 +3918,12 @@ static int prepare_allocation(struct btrfs_fs_info *fs_info,
  * |- 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(struct btrfs_fs_info *fs_info,
        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_root *root, u64 ram_bytes,
        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);

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 863335e..b924183 100644 (file)
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1176,25 +1176,27 @@ DEFINE_EVENT(btrfs__reserved_extent,  btrfs_reserved_extent_free,
 
 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))