The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 437490fed3b0c9ae21af8f70e0f338d34560842b Mon Sep 17 00:00:00 2001
From: Qu Wenruo wqu@suse.com Date: Tue, 28 Jul 2020 09:42:49 +0800 Subject: [PATCH] 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 780b9c9a98fe..dbff61d36cab 100644 --- 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 863335ecb7e8..b9241836d4f7 100644 --- 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))