btrfs: tracepoints: Add trace events for extent_io_tree

Although btrfs heavily relies on extent_io_tree, we don't really have
any good trace events for them.

This patch will add the folowing trace events:
- trace_btrfs_set_extent_bit()
- trace_btrfs_clear_extent_bit()
- trace_btrfs_convert_extent_bit()

Since selftests could create temporary extent_io_tree without fs_info,
modify TP_fast_assign_fsid() to accept NULL as fs_info.  NULL fs_info
will lead to all zero fsid.

The output would be:
  btrfs_set_extent_bit: <FDID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=4096 set_bits=LOCKED
  btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22040576 len=4096 set_bits=LOCKED
  btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22044672 len=4096 set_bits=LOCKED
  btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22048768 len=4096 set_bits=LOCKED
  btrfs_clear_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=16384 clear_bits=LOCKED
  ^^^ Extent buffer 22036480 read from disk, the locking progress

  btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30425088 len=16384 set_bits=DIRTY
  btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30441472 len=16384 set_bits=DIRTY
  ^^^ 2 new tree blocks allocated in one transaction

  btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30523392 len=16384 set_bits=DIRTY
  btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30556160 len=16384 set_bits=DIRTY
  ^^^ 2 old tree blocks get pinned down

There is one point which need attention:
1) Those trace events can be pretty heavy:
   The following workload would generate over 400 trace events.

	mkfs.btrfs -f $dev
	start_trace
	mount $dev $mnt -o enospc_debug
	sync
	touch $mnt/file1
	touch $mnt/file2
	touch $mnt/file3
	xfs_io -f -c "pwrite 0 16k" $mnt/file4
	umount $mnt
	end_trace

   It's not recommended to use them in real world environment.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ rename enums ]
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index cfd2b23..ee246a7 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -614,6 +614,7 @@ int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
        int clear = 0;
 
        btrfs_debug_check_extent_io_range(tree, start, end);
+       trace_btrfs_clear_extent_bit(tree, start, end - start + 1, bits);
 
        if (bits & EXTENT_DELALLOC)
                bits |= EXTENT_NORESERVE;
@@ -883,6 +884,7 @@ __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
        u64 last_end;
 
        btrfs_debug_check_extent_io_range(tree, start, end);
+       trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits);
 
 again:
        if (!prealloc && gfpflags_allow_blocking(mask)) {
@@ -1115,6 +1117,8 @@ int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
        bool first_iteration = true;
 
        btrfs_debug_check_extent_io_range(tree, start, end);
+       trace_btrfs_convert_extent_bit(tree, start, end - start + 1, bits,
+                                      clear_bits);
 
 again:
        if (!prealloc) {

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index ab1cc33..74a11b2 100644 (file)
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -27,6 +27,7 @@ struct btrfs_work;
 struct __btrfs_workqueue;
 struct btrfs_qgroup_extent_record;
 struct btrfs_qgroup;
+struct extent_io_tree;
 struct prelim_ref;
 
 TRACE_DEFINE_ENUM(FLUSH_DELAYED_ITEMS_NR);
@@ -77,6 +78,17 @@ TRACE_DEFINE_ENUM(COMMIT_TRANS);
                { BTRFS_QGROUP_RSV_META_PERTRANS, "META_PERTRANS" },    \
                { BTRFS_QGROUP_RSV_META_PREALLOC, "META_PREALLOC" })
 
+#define show_extent_io_tree_owner(owner)                                      \
+       __print_symbolic(owner,                                                \
+               { IO_TREE_FS_INFO_FREED_EXTENTS0, "FREED_EXTENTS0" },          \
+               { IO_TREE_FS_INFO_FREED_EXTENTS1, "FREED_EXTENTS1" },          \
+               { IO_TREE_INODE_IO,               "INODE_IO" },                \
+               { IO_TREE_INODE_IO_FAILURE,       "INODE_IO_FAILURE" },        \
+               { IO_TREE_RELOC_BLOCKS,           "RELOC_BLOCKS" },            \
+               { IO_TREE_TRANS_DIRTY_PAGES,      "TRANS_DIRTY_PAGES" },       \
+               { IO_TREE_ROOT_DIRTY_LOG_PAGES,   "ROOT_DIRTY_LOG_PAGES" },    \
+               { IO_TREE_SELFTEST,               "SELFTEST" })
+
 #define BTRFS_GROUP_FLAGS      \
        { BTRFS_BLOCK_GROUP_DATA,       "DATA"},        \
        { BTRFS_BLOCK_GROUP_SYSTEM,     "SYSTEM"},      \
@@ -88,11 +100,35 @@ TRACE_DEFINE_ENUM(COMMIT_TRANS);
        { BTRFS_BLOCK_GROUP_RAID5,      "RAID5"},       \
        { BTRFS_BLOCK_GROUP_RAID6,      "RAID6"}
 
+#define EXTENT_FLAGS                                           \
+       { EXTENT_DIRTY,                 "DIRTY"},               \
+       { EXTENT_WRITEBACK,             "WRITEBACK"},           \
+       { EXTENT_UPTODATE,              "UPTODATE"},            \
+       { EXTENT_LOCKED,                "LOCKED"},              \
+       { EXTENT_NEW,                   "NEW"},                 \
+       { EXTENT_DELALLOC,              "DELALLOC"},            \
+       { EXTENT_DEFRAG,                "DEFRAG"},              \
+       { EXTENT_BOUNDARY,              "BOUNDARY"},            \
+       { EXTENT_NODATASUM,             "NODATASUM"},           \
+       { EXTENT_CLEAR_META_RESV,       "CLEAR_META_RESV"},     \
+       { EXTENT_NEED_WAIT,             "NEED_WAIT"},           \
+       { EXTENT_DAMAGED,               "DAMAGED"},             \
+       { EXTENT_NORESERVE,             "NORESERVE"},           \
+       { EXTENT_QGROUP_RESERVED,       "QGROUP_RESERVED"},     \
+       { EXTENT_CLEAR_DATA_RESV,       "CLEAR_DATA_RESV"},     \
+       { EXTENT_DELALLOC_NEW,          "DELALLOC_NEW"}
+
 #define BTRFS_FSID_SIZE 16
 #define TP_STRUCT__entry_fsid __array(u8, fsid, BTRFS_FSID_SIZE)
 
 #define TP_fast_assign_fsid(fs_info)                                   \
-       memcpy(__entry->fsid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE)
+({                                                                     \
+       if (fs_info)                                                    \
+               memcpy(__entry->fsid, fs_info->fs_devices->fsid,        \
+                      BTRFS_FSID_SIZE);                                \
+       else                                                            \
+               memset(__entry->fsid, 0, BTRFS_FSID_SIZE);              \
+})
 
 #define TP_STRUCT__entry_btrfs(args...)                                        \
        TP_STRUCT__entry(                                               \
@@ -1850,6 +1886,126 @@ DEFINE_EVENT(btrfs__block_group, btrfs_skip_unused_block_group,
        TP_ARGS(bg_cache)
 );
 
+TRACE_EVENT(btrfs_set_extent_bit,
+       TP_PROTO(const struct extent_io_tree *tree,
+                u64 start, u64 len, unsigned set_bits),
+
+       TP_ARGS(tree, start, len, set_bits),
+
+       TP_STRUCT__entry_btrfs(
+               __field(        unsigned,       owner   )
+               __field(        u64,            ino     )
+               __field(        u64,            rootid  )
+               __field(        u64,            start   )
+               __field(        u64,            len     )
+               __field(        unsigned,       set_bits)
+       ),
+
+       TP_fast_assign_btrfs(tree->fs_info,
+               __entry->owner = tree->owner;
+               if (tree->private_data) {
+                       struct inode *inode = tree->private_data;
+
+                       __entry->ino    = btrfs_ino(BTRFS_I(inode));
+                       __entry->rootid =
+                               BTRFS_I(inode)->root->root_key.objectid;
+               } else {
+                       __entry->ino    = 0;
+                       __entry->rootid = 0;
+               }
+               __entry->start          = start;
+               __entry->len            = len;
+               __entry->set_bits       = set_bits;
+       ),
+
+       TP_printk_btrfs(
+               "io_tree=%s ino=%llu root=%llu start=%llu len=%llu set_bits=%s",
+               show_extent_io_tree_owner(__entry->owner), __entry->ino,
+               __entry->rootid, __entry->start, __entry->len,
+               __print_flags(__entry->set_bits, "|", EXTENT_FLAGS))
+);
+
+TRACE_EVENT(btrfs_clear_extent_bit,
+       TP_PROTO(const struct extent_io_tree *tree,
+                u64 start, u64 len, unsigned clear_bits),
+
+       TP_ARGS(tree, start, len, clear_bits),
+
+       TP_STRUCT__entry_btrfs(
+               __field(        unsigned,       owner   )
+               __field(        u64,            ino     )
+               __field(        u64,            rootid  )
+               __field(        u64,            start   )
+               __field(        u64,            len     )
+               __field(        unsigned,       clear_bits)
+       ),
+
+       TP_fast_assign_btrfs(tree->fs_info,
+               __entry->owner = tree->owner;
+               if (tree->private_data) {
+                       struct inode *inode = tree->private_data;
+
+                       __entry->ino    = btrfs_ino(BTRFS_I(inode));
+                       __entry->rootid =
+                               BTRFS_I(inode)->root->root_key.objectid;
+               } else {
+                       __entry->ino    = 0;
+                       __entry->rootid = 0;
+               }
+               __entry->start          = start;
+               __entry->len            = len;
+               __entry->clear_bits     = clear_bits;
+       ),
+
+       TP_printk_btrfs(
+               "io_tree=%s ino=%llu root=%llu start=%llu len=%llu clear_bits=%s",
+               show_extent_io_tree_owner(__entry->owner), __entry->ino,
+               __entry->rootid, __entry->start, __entry->len,
+               __print_flags(__entry->clear_bits, "|", EXTENT_FLAGS))
+);
+
+TRACE_EVENT(btrfs_convert_extent_bit,
+       TP_PROTO(const struct extent_io_tree *tree,
+                u64 start, u64 len, unsigned set_bits, unsigned clear_bits),
+
+       TP_ARGS(tree, start, len, set_bits, clear_bits),
+
+       TP_STRUCT__entry_btrfs(
+               __field(        unsigned,       owner   )
+               __field(        u64,            ino     )
+               __field(        u64,            rootid  )
+               __field(        u64,            start   )
+               __field(        u64,            len     )
+               __field(        unsigned,       set_bits)
+               __field(        unsigned,       clear_bits)
+       ),
+
+       TP_fast_assign_btrfs(tree->fs_info,
+               __entry->owner = tree->owner;
+               if (tree->private_data) {
+                       struct inode *inode = tree->private_data;
+
+                       __entry->ino    = btrfs_ino(BTRFS_I(inode));
+                       __entry->rootid =
+                               BTRFS_I(inode)->root->root_key.objectid;
+               } else {
+                       __entry->ino    = 0;
+                       __entry->rootid = 0;
+               }
+               __entry->start          = start;
+               __entry->len            = len;
+               __entry->set_bits       = set_bits;
+               __entry->clear_bits     = clear_bits;
+       ),
+
+       TP_printk_btrfs(
+"io_tree=%s ino=%llu root=%llu start=%llu len=%llu set_bits=%s clear_bits=%s",
+                 show_extent_io_tree_owner(__entry->owner), __entry->ino,
+                 __entry->rootid, __entry->start, __entry->len,
+                 __print_flags(__entry->set_bits , "|", EXTENT_FLAGS),
+                 __print_flags(__entry->clear_bits, "|", EXTENT_FLAGS))
+);
+
 #endif /* _TRACE_BTRFS_H */
 
 /* This part must be outside protection */