[PATCH 29/67] cachefiles: Trace read and write operations

David Howells
2021-10-18T14:58:16Z

Add tracepoints for read and write operations on cache files.

Signed-off-by: David Howells <dhowells@redhat.com>
---

fs/cachefiles/io.c | 6 +++-
include/trace/events/cachefiles.h | 58 +++++++++++++++++++++++++++++++++++++
2 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
index 0e1fb44b5d04..f703a93e238b 100644
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -62,6 +62,7 @@ static int cachefiles_read(struct netfs_cache_resources *cres,
netfs_io_terminated_t term_func,
void *term_func_priv)
{
+ struct cachefiles_object *object = cres->cache_priv;
struct cachefiles_kiocb *ki;
struct file *file = cachefiles_cres_file(cres);
unsigned int old_nofs;
@@ -124,6 +125,7 @@ static int cachefiles_read(struct netfs_cache_resources *cres,

get_file(ki->iocb.ki_filp);

+ trace_cachefiles_read(object, file_inode(file), ki->iocb.ki_pos, len - skipped);
old_nofs = memalloc_nofs_save();
ret = vfs_iocb_iter_read(file, &ki->iocb, iter);
memalloc_nofs_restore(old_nofs);
@@ -188,6 +190,7 @@ static int cachefiles_write(struct netfs_cache_resources *cres,
netfs_io_terminated_t term_func,
void *term_func_priv)
{
+ struct cachefiles_object *object = cres->cache_priv;
struct cachefiles_kiocb *ki;
struct inode *inode;
struct file *file = cachefiles_cres_file(cres);
@@ -229,6 +232,7 @@ static int cachefiles_write(struct netfs_cache_resources *cres,

get_file(ki->iocb.ki_filp);

+ trace_cachefiles_write(object, inode, ki->iocb.ki_pos, len);
old_nofs = memalloc_nofs_save();
ret = vfs_iocb_iter_write(file, &ki->iocb, iter);
memalloc_nofs_restore(old_nofs);
@@ -418,7 +422,7 @@ int cachefiles_begin_operation(struct netfs_cache_resources *cres)

_enter("");

- cres->cache_priv = op;
+ cres->cache_priv = object;
cres->cache_priv2 = get_file(object->file);
cres->ops = &cachefiles_netfs_cache_ops;
cres->debug_id = object->cookie->debug_id;
diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
index 09d76c160451..47df44550ad6 100644
--- a/include/trace/events/cachefiles.h
+++ b/include/trace/events/cachefiles.h
@@ -302,6 +302,64 @@ TRACE_EVENT(cachefiles_coherency,
__entry->content)
);

+TRACE_EVENT(cachefiles_read,
+ TP_PROTO(struct cachefiles_object *obj,
+ struct inode *backer,
+ loff_t start,
+ size_t len),
+
+ TP_ARGS(obj, backer, start, len),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, obj )
+ __field(unsigned int, backer )
+ __field(size_t, len )
+ __field(loff_t, start )
+ ),
+
+ TP_fast_assign(
+ __entry->obj = obj->debug_id;
+ __entry->backer = backer->i_ino;
+ __entry->start = start;
+ __entry->len = len;
+ ),
+
+ TP_printk("o=%08x b=%08x s=%llx l=%zx",
+ __entry->obj,
+ __entry->backer,
+ __entry->start,
+ __entry->len)
+ );
+
+TRACE_EVENT(cachefiles_write,
+ TP_PROTO(struct cachefiles_object *obj,
+ struct inode *backer,
+ loff_t start,
+ size_t len),
+
+ TP_ARGS(obj, backer, start, len),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, obj )
+ __field(unsigned int, backer )
+ __field(size_t, len )
+ __field(loff_t, start )
+ ),
+
+ TP_fast_assign(
+ __entry->obj = obj->debug_id;
+ __entry->backer = backer->i_ino;
+ __entry->start = start;
+ __entry->len = len;
+ ),
+
+ TP_printk("o=%08x b=%08x s=%llx l=%zx",
+ __entry->obj,
+ __entry->backer,
+ __entry->start,
+ __entry->len)
+ );
+
TRACE_EVENT(cachefiles_trunc,
TP_PROTO(struct cachefiles_object *obj, struct inode *backer,
loff_t from, loff_t to, enum cachefiles_trunc_trace why),