LinuxLists.cc - [PATCH 1/2] ext4: fix symbolic enum printing in trace output

2019-11-14 20:02:38

Subject: [PATCH 1/2] ext4: fix symbolic enum printing in trace output

Trace's macro __print_flags() produce raw event's decraration w/o knowing actual
flags value

cat /sys/kernel/debug/tracing/events/ext4/ext4_ext_map_blocks_exit/format
..
__print_flags(REC->mflags, "", { (1 << BH_New),

For that reason we have to explicitly define it via special macro TRACE_DEFINE_ENUM()
Also add missed EXTENT_STATUS_REFERENCED flag.

#Before patch
ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 2 flags lblk 0 pblk 4177 len 1 mflags 0x20 ret 1
ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 12 flags CREATE lblk 0 pblk 34304 len 1 mflags 0x60 ret 1

#With patch
ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 2 flags lblk 0 pblk 4177 len 1 mflags M ret 1
ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 12 flags CREATE lblk 0 pblk 34816 len 1 mflags NM ret 1

Signed-off-by: Dmitry Monakhov <[email protected]>
---
include/trace/events/ext4.h | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 182c9fe..3bf7128 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -48,6 +48,16 @@ struct partial_cluster;
{ EXT4_GET_BLOCKS_KEEP_SIZE, "KEEP_SIZE" }, \
{ EXT4_GET_BLOCKS_ZERO, "ZERO" })

+/*
+ * __print_flags() requires that all enum values be wrapped in the
+ * TRACE_DEFINE_ENUM macro so that the enum value can be encoded in the ftrace
+ * ring buffer.
+ */
+TRACE_DEFINE_ENUM(BH_New);
+TRACE_DEFINE_ENUM(BH_Mapped);
+TRACE_DEFINE_ENUM(BH_Unwritten);
+TRACE_DEFINE_ENUM(BH_Boundary);
+
#define show_mflags(flags) __print_flags(flags, "", \
{ EXT4_MAP_NEW, "N" }, \
{ EXT4_MAP_MAPPED, "M" }, \
@@ -62,11 +72,18 @@ struct partial_cluster;
{ EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER,"1ST_CLUSTER" },\
{ EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER, "LAST_CLUSTER" })

+TRACE_DEFINE_ENUM(ES_WRITTEN_B);
+TRACE_DEFINE_ENUM(ES_UNWRITTEN_B);
+TRACE_DEFINE_ENUM(ES_DELAYED_B);
+TRACE_DEFINE_ENUM(ES_HOLE_B);
+TRACE_DEFINE_ENUM(ES_REFERENCED_B);
+
#define show_extent_status(status) __print_flags(status, "", \
{ EXTENT_STATUS_WRITTEN, "W" }, \
{ EXTENT_STATUS_UNWRITTEN, "U" }, \
{ EXTENT_STATUS_DELAYED, "D" }, \
- { EXTENT_STATUS_HOLE, "H" })
+ { EXTENT_STATUS_HOLE, "H" }, \
+ { EXTENT_STATUS_REFERENCED, "R" })

#define show_falloc_mode(mode) __print_flags(mode, "|", \
{ FALLOC_FL_KEEP_SIZE, "KEEP_SIZE"}, \
--
2.7.4

2019-11-14 20:02:40

by Dmitry Monakhov

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Subject: [PATCH 2/2] ext4: fix extent_status trace points

Show pblock only if it has meaningful value.

# before
ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [1/4294967294) 576460752303423487 H
ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [2/4294967293) 576460752303423487 HR
# after
ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [1/4294967294) 0 H
ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [2/4294967293) 0 HR

Signed-off-by: Dmitry Monakhov <[email protected]>
---
fs/ext4/extents_status.h | 6 ++++++
include/trace/events/ext4.h | 8 ++++----
2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index 825313c..4ec30a7 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -209,6 +209,12 @@ static inline ext4_fsblk_t ext4_es_pblock(struct extent_status *es)
return es->es_pblk & ~ES_MASK;
}

+static inline ext4_fsblk_t ext4_es_show_pblock(struct extent_status *es)
+{
+ ext4_fsblk_t pblock = ext4_es_pblock(es);
+ return pblock == ~ES_MASK ? 0 : pblock;
+}
+
static inline void ext4_es_store_pblock(struct extent_status *es,
ext4_fsblk_t pb)
{
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 3bf7128..19c8766 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -2282,7 +2282,7 @@ DECLARE_EVENT_CLASS(ext4__es_extent,
__entry->ino = inode->i_ino;
__entry->lblk = es->es_lblk;
__entry->len = es->es_len;
- __entry->pblk = ext4_es_pblock(es);
+ __entry->pblk = ext4_es_show_pblock(es);
__entry->status = ext4_es_status(es);
),

@@ -2371,7 +2371,7 @@ TRACE_EVENT(ext4_es_find_extent_range_exit,
__entry->ino = inode->i_ino;
__entry->lblk = es->es_lblk;
__entry->len = es->es_len;
- __entry->pblk = ext4_es_pblock(es);
+ __entry->pblk = ext4_es_show_pblock(es);
__entry->status = ext4_es_status(es);
),

@@ -2425,7 +2425,7 @@ TRACE_EVENT(ext4_es_lookup_extent_exit,
__entry->ino = inode->i_ino;
__entry->lblk = es->es_lblk;
__entry->len = es->es_len;
- __entry->pblk = ext4_es_pblock(es);
+ __entry->pblk = ext4_es_show_pblock(es);
__entry->status = ext4_es_status(es);
__entry->found = found;
),
@@ -2593,7 +2593,7 @@ TRACE_EVENT(ext4_es_insert_delayed_block,
__entry->ino = inode->i_ino;
__entry->lblk = es->es_lblk;
__entry->len = es->es_len;
- __entry->pblk = ext4_es_pblock(es);
+ __entry->pblk = ext4_es_show_pblock(es);
__entry->status = ext4_es_status(es);
__entry->allocated = allocated;
),
--
2.7.4

2019-11-14 21:04:36

by Darrick J. Wong

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Subject: Re: [PATCH 1/2] ext4: fix symbolic enum printing in trace output

On Thu, Nov 14, 2019 at 08:01:46PM +0000, Dmitry Monakhov wrote:
> Trace's macro __print_flags() produce raw event's decraration w/o knowing actual
> flags value
>
> cat /sys/kernel/debug/tracing/events/ext4/ext4_ext_map_blocks_exit/format
> ..
> __print_flags(REC->mflags, "", { (1 << BH_New),
>
> For that reason we have to explicitly define it via special macro TRACE_DEFINE_ENUM()
> Also add missed EXTENT_STATUS_REFERENCED flag.
>
> #Before patch
> ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 2 flags lblk 0 pblk 4177 len 1 mflags 0x20 ret 1
> ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 12 flags CREATE lblk 0 pblk 34304 len 1 mflags 0x60 ret 1
>
> #With patch
> ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 2 flags lblk 0 pblk 4177 len 1 mflags M ret 1
> ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 12 flags CREATE lblk 0 pblk 34816 len 1 mflags NM ret 1
>
> Signed-off-by: Dmitry Monakhov <[email protected]>
> ---
> include/trace/events/ext4.h | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
> index 182c9fe..3bf7128 100644
> --- a/include/trace/events/ext4.h
> +++ b/include/trace/events/ext4.h
> @@ -48,6 +48,16 @@ struct partial_cluster;
> { EXT4_GET_BLOCKS_KEEP_SIZE, "KEEP_SIZE" }, \
> { EXT4_GET_BLOCKS_ZERO, "ZERO" })
>
> +/*
> + * __print_flags() requires that all enum values be wrapped in the
> + * TRACE_DEFINE_ENUM macro so that the enum value can be encoded in the ftrace
> + * ring buffer.
> + */
> +TRACE_DEFINE_ENUM(BH_New);
> +TRACE_DEFINE_ENUM(BH_Mapped);
> +TRACE_DEFINE_ENUM(BH_Unwritten);
> +TRACE_DEFINE_ENUM(BH_Boundary);
> +
> #define show_mflags(flags) __print_flags(flags, "", \
> { EXT4_MAP_NEW, "N" }, \
> { EXT4_MAP_MAPPED, "M" }, \
> @@ -62,11 +72,18 @@ struct partial_cluster;
> { EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER,"1ST_CLUSTER" },\
> { EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER, "LAST_CLUSTER" })
>
> +TRACE_DEFINE_ENUM(ES_WRITTEN_B);
> +TRACE_DEFINE_ENUM(ES_UNWRITTEN_B);
> +TRACE_DEFINE_ENUM(ES_DELAYED_B);
> +TRACE_DEFINE_ENUM(ES_HOLE_B);
> +TRACE_DEFINE_ENUM(ES_REFERENCED_B);

I wonder if it's worth leaving a comment wherever this enum is defined
warning developers to keep this TRACE_DEFINE_NUM list (and the string
mapping) up to date?

--D

> #define show_extent_status(status) __print_flags(status, "", \
> { EXTENT_STATUS_WRITTEN, "W" }, \
> { EXTENT_STATUS_UNWRITTEN, "U" }, \
> { EXTENT_STATUS_DELAYED, "D" }, \
> - { EXTENT_STATUS_HOLE, "H" })
> + { EXTENT_STATUS_HOLE, "H" }, \
> + { EXTENT_STATUS_REFERENCED, "R" })
>
> #define show_falloc_mode(mode) __print_flags(mode, "|", \
> { FALLOC_FL_KEEP_SIZE, "KEEP_SIZE"}, \
> --
> 2.7.4
>

2020-01-25 07:07:55

by Theodore Ts'o

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Subject: Re: [PATCH 2/2] ext4: fix extent_status trace points

On Thu, Nov 14, 2019 at 08:01:47PM +0000, Dmitry Monakhov wrote:
> Show pblock only if it has meaningful value.
>
> # before
> ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [1/4294967294) 576460752303423487 H
> ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [2/4294967293) 576460752303423487 HR
> # after
> ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [1/4294967294) 0 H
> ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [2/4294967293) 0 HR
>
> Signed-off-by: Dmitry Monakhov <[email protected]>

Thanks, applied.

- Ted

2020-01-25 07:08:20

by Theodore Ts'o

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