[PATCH 04/11] cachefiles: Make some tracepoint adjustments

From: David Howells
Date: Tue Jan 18 2022 - 08:54:37 EST

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Make some adjustments to tracepoints to make the tracing a bit more
followable:

(1) Standardise on displaying the backing inode number as "B=<hex>" with
no leading zeros.

(2) Make the cachefiles_lookup tracepoint log the directory inode number
as well as the looked-up inode number.

(3) Add a cachefiles_lookup tracepoint into cachefiles_get_directory() to
log directory lookup.

(4) Add a new cachefiles_mkdir tracepoint and use that to log a successful
mkdir from cachefiles_get_directory().

(5) Make the cachefiles_unlink and cachefiles_rename tracepoints log the
inode number of the affected file/dir rather than dentry struct
pointers.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: linux-cachefs@xxxxxxxxxx
---

fs/cachefiles/namei.c | 8 ++--
include/trace/events/cachefiles.h | 82 +++++++++++++++++++++++--------------
2 files changed, 56 insertions(+), 34 deletions(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 9bd692870617..52c9f0864a87 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -101,6 +101,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
subdir = lookup_one_len(dirname, dir, strlen(dirname));
else
subdir = ERR_PTR(ret);
+ trace_cachefiles_lookup(NULL, dir, subdir);
if (IS_ERR(subdir)) {
trace_cachefiles_vfs_error(NULL, d_backing_inode(dir),
PTR_ERR(subdir),
@@ -135,6 +136,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
cachefiles_trace_mkdir_error);
goto mkdir_error;
}
+ trace_cachefiles_mkdir(dir, subdir);

if (unlikely(d_unhashed(subdir))) {
cachefiles_put_directory(subdir);
@@ -233,7 +235,7 @@ static int cachefiles_unlink(struct cachefiles_cache *cache,
};
int ret;

- trace_cachefiles_unlink(object, dentry, why);
+ trace_cachefiles_unlink(object, d_inode(dentry)->i_ino, why);
ret = security_path_unlink(&path, dentry);
if (ret < 0) {
cachefiles_io_error(cache, "Unlink security error");
@@ -386,7 +388,7 @@ int cachefiles_bury_object(struct cachefiles_cache *cache,
.new_dir = d_inode(cache->graveyard),
.new_dentry = grave,
};
- trace_cachefiles_rename(object, rep, grave, why);
+ trace_cachefiles_rename(object, d_inode(rep)->i_ino, why);
ret = cachefiles_inject_read_error();
if (ret == 0)
ret = vfs_rename(&rd);
@@ -617,7 +619,7 @@ bool cachefiles_look_up_object(struct cachefiles_object *object)
object->d_name_len);
else
dentry = ERR_PTR(ret);
- trace_cachefiles_lookup(object, dentry);
+ trace_cachefiles_lookup(object, fan, dentry);
if (IS_ERR(dentry)) {
if (dentry == ERR_PTR(-ENOENT))
goto new_file;
diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
index 1172529b5b49..093c4acb7a3a 100644
--- a/include/trace/events/cachefiles.h
+++ b/include/trace/events/cachefiles.h
@@ -233,25 +233,48 @@ TRACE_EVENT(cachefiles_ref,

TRACE_EVENT(cachefiles_lookup,
TP_PROTO(struct cachefiles_object *obj,
+ struct dentry *dir,
struct dentry *de),

- TP_ARGS(obj, de),
+ TP_ARGS(obj, dir, de),

TP_STRUCT__entry(
__field(unsigned int, obj )
__field(short, error )
+ __field(unsigned long, dino )
__field(unsigned long, ino )
),

TP_fast_assign(
- __entry->obj = obj->debug_id;
+ __entry->obj = obj ? obj->debug_id : 0;
+ __entry->dino = d_backing_inode(dir)->i_ino;
__entry->ino = (!IS_ERR(de) && d_backing_inode(de) ?
d_backing_inode(de)->i_ino : 0);
__entry->error = IS_ERR(de) ? PTR_ERR(de) : 0;
),

- TP_printk("o=%08x i=%lx e=%d",
- __entry->obj, __entry->ino, __entry->error)
+ TP_printk("o=%08x dB=%lx B=%lx e=%d",
+ __entry->obj, __entry->dino, __entry->ino, __entry->error)
+ );
+
+TRACE_EVENT(cachefiles_mkdir,
+ TP_PROTO(struct dentry *dir, struct dentry *subdir),
+
+ TP_ARGS(dir, subdir),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, dir )
+ __field(unsigned int, subdir )
+ ),
+
+ TP_fast_assign(
+ __entry->dir = d_backing_inode(dir)->i_ino;
+ __entry->subdir = d_backing_inode(subdir)->i_ino;
+ ),
+
+ TP_printk("dB=%x sB=%x",
+ __entry->dir,
+ __entry->subdir)
);

TRACE_EVENT(cachefiles_tmpfile,
@@ -269,7 +292,7 @@ TRACE_EVENT(cachefiles_tmpfile,
__entry->backer = backer->i_ino;
),

- TP_printk("o=%08x b=%08x",
+ TP_printk("o=%08x B=%x",
__entry->obj,
__entry->backer)
);
@@ -289,61 +312,58 @@ TRACE_EVENT(cachefiles_link,
__entry->backer = backer->i_ino;
),

- TP_printk("o=%08x b=%08x",
+ TP_printk("o=%08x B=%x",
__entry->obj,
__entry->backer)
);

TRACE_EVENT(cachefiles_unlink,
TP_PROTO(struct cachefiles_object *obj,
- struct dentry *de,
+ ino_t ino,
enum fscache_why_object_killed why),

- TP_ARGS(obj, de, why),
+ TP_ARGS(obj, ino, why),

/* Note that obj may be NULL */
TP_STRUCT__entry(
__field(unsigned int, obj )
- __field(struct dentry *, de )
+ __field(unsigned int, ino )
__field(enum fscache_why_object_killed, why )
),

TP_fast_assign(
__entry->obj = obj ? obj->debug_id : UINT_MAX;
- __entry->de = de;
+ __entry->ino = ino;
__entry->why = why;
),

- TP_printk("o=%08x d=%p w=%s",
- __entry->obj, __entry->de,
+ TP_printk("o=%08x B=%x w=%s",
+ __entry->obj, __entry->ino,
__print_symbolic(__entry->why, cachefiles_obj_kill_traces))
);

TRACE_EVENT(cachefiles_rename,
TP_PROTO(struct cachefiles_object *obj,
- struct dentry *de,
- struct dentry *to,
+ ino_t ino,
enum fscache_why_object_killed why),

- TP_ARGS(obj, de, to, why),
+ TP_ARGS(obj, ino, why),

/* Note that obj may be NULL */
TP_STRUCT__entry(
__field(unsigned int, obj )
- __field(struct dentry *, de )
- __field(struct dentry *, to )
+ __field(unsigned int, ino )
__field(enum fscache_why_object_killed, why )
),

TP_fast_assign(
__entry->obj = obj ? obj->debug_id : UINT_MAX;
- __entry->de = de;
- __entry->to = to;
+ __entry->ino = ino;
__entry->why = why;
),

- TP_printk("o=%08x d=%p t=%p w=%s",
- __entry->obj, __entry->de, __entry->to,
+ TP_printk("o=%08x B=%x w=%s",
+ __entry->obj, __entry->ino,
__print_symbolic(__entry->why, cachefiles_obj_kill_traces))
);

@@ -370,7 +390,7 @@ TRACE_EVENT(cachefiles_coherency,
__entry->ino = ino;
),

- TP_printk("o=%08x %s i=%llx c=%u",
+ TP_printk("o=%08x %s B=%llx c=%u",
__entry->obj,
__print_symbolic(__entry->why, cachefiles_coherency_traces),
__entry->ino,
@@ -397,7 +417,7 @@ TRACE_EVENT(cachefiles_vol_coherency,
__entry->ino = ino;
),

- TP_printk("V=%08x %s i=%llx",
+ TP_printk("V=%08x %s B=%llx",
__entry->vol,
__print_symbolic(__entry->why, cachefiles_coherency_traces),
__entry->ino)
@@ -435,7 +455,7 @@ TRACE_EVENT(cachefiles_prep_read,
__entry->cache_inode = cache_inode;
),

- TP_printk("R=%08x[%u] %s %s f=%02x s=%llx %zx ni=%x b=%x",
+ TP_printk("R=%08x[%u] %s %s f=%02x s=%llx %zx ni=%x B=%x",
__entry->rreq, __entry->index,
__print_symbolic(__entry->source, netfs_sreq_sources),
__print_symbolic(__entry->why, cachefiles_prepare_read_traces),
@@ -466,7 +486,7 @@ TRACE_EVENT(cachefiles_read,
__entry->len = len;
),

- TP_printk("o=%08x b=%08x s=%llx l=%zx",
+ TP_printk("o=%08x B=%x s=%llx l=%zx",
__entry->obj,
__entry->backer,
__entry->start,
@@ -495,7 +515,7 @@ TRACE_EVENT(cachefiles_write,
__entry->len = len;
),

- TP_printk("o=%08x b=%08x s=%llx l=%zx",
+ TP_printk("o=%08x B=%x s=%llx l=%zx",
__entry->obj,
__entry->backer,
__entry->start,
@@ -524,7 +544,7 @@ TRACE_EVENT(cachefiles_trunc,
__entry->why = why;
),

- TP_printk("o=%08x b=%08x %s l=%llx->%llx",
+ TP_printk("o=%08x B=%x %s l=%llx->%llx",
__entry->obj,
__entry->backer,
__print_symbolic(__entry->why, cachefiles_trunc_traces),
@@ -549,7 +569,7 @@ TRACE_EVENT(cachefiles_mark_active,
__entry->inode = inode->i_ino;
),

- TP_printk("o=%08x i=%lx",
+ TP_printk("o=%08x B=%lx",
__entry->obj, __entry->inode)
);

@@ -570,7 +590,7 @@ TRACE_EVENT(cachefiles_mark_inactive,
__entry->inode = inode->i_ino;
),

- TP_printk("o=%08x i=%lx",
+ TP_printk("o=%08x B=%lx",
__entry->obj, __entry->inode)
);

@@ -594,7 +614,7 @@ TRACE_EVENT(cachefiles_vfs_error,
__entry->where = where;
),

- TP_printk("o=%08x b=%08x %s e=%d",
+ TP_printk("o=%08x B=%x %s e=%d",
__entry->obj,
__entry->backer,
__print_symbolic(__entry->where, cachefiles_error_traces),
@@ -621,7 +641,7 @@ TRACE_EVENT(cachefiles_io_error,
__entry->where = where;
),

- TP_printk("o=%08x b=%08x %s e=%d",
+ TP_printk("o=%08x B=%x %s e=%d",
__entry->obj,
__entry->backer,
__print_symbolic(__entry->where, cachefiles_error_traces),

Next message: David Howells: "[PATCH 06/11] cachefiles: Explain checks in a comment"
Previous message: David Howells: "[PATCH 03/11] cachefiles: set default tag name if it's unspecified"
In reply to: Jeff Layton: "Re: [PATCH 03/11] cachefiles: set default tag name if it's unspecified"
Next in thread: Jeff Layton: "Re: [PATCH 04/11] cachefiles: Make some tracepoint adjustments"
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