Commit de74023b authored by David Howells's avatar David Howells
Browse files

netfs: Trace refcounting on the netfs_io_request struct 



Add refcount tracing for the netfs_io_request structure.

Changes
=======
ver #3)
 - Switch 'W=' to 'R=' in the traceline to match other request debug IDs.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/164622997668.3564931.14456171619219324968.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678200943.1200972.7241495532327787765.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692900920.2099075.11847712419940675791.stgit@warthog.procyon.org.uk/ # v3
parent 18b3ff9f

fs/netfs/internal.h

+9 −2
Original line number Diff line number Diff line
@@ -20,13 +20,20 @@ 
struct netfs_io_request *netfs_alloc_request(const struct netfs_request_ops *ops,

					     void *netfs_priv,

					     struct file *file);

void netfs_get_request(struct netfs_io_request *rreq);

void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what);

void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async);

void netfs_put_request(struct netfs_io_request *rreq, bool was_async);

void netfs_put_request(struct netfs_io_request *rreq, bool was_async,

		       enum netfs_rreq_ref_trace what);

struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq);

void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async);

void netfs_get_subrequest(struct netfs_io_subrequest *subreq);



static inline void netfs_see_request(struct netfs_io_request *rreq,

				     enum netfs_rreq_ref_trace what)

{

	trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), what);

}



/*

 * read_helper.c

 */

fs/netfs/objects.c

+17 −7
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ struct netfs_io_request *netfs_alloc_request( 
		rreq->debug_id	= atomic_inc_return(&debug_ids);

		INIT_LIST_HEAD(&rreq->subrequests);

		INIT_WORK(&rreq->work, netfs_rreq_work);

		refcount_set(&rreq->usage, 1);

		refcount_set(&rreq->ref, 1);

		__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);

		if (ops->init_request)

			ops->init_request(rreq, file);
@@ -37,9 +37,12 @@ struct netfs_io_request *netfs_alloc_request( 
	return rreq;

}



void netfs_get_request(struct netfs_io_request *rreq)

void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)

{

	refcount_inc(&rreq->usage);

	int r;



	__refcount_inc(&rreq->ref, &r);

	trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);

}



void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
@@ -68,9 +71,16 @@ static void netfs_free_request(struct work_struct *work) 
	netfs_stat_d(&netfs_n_rh_rreq);

}



void netfs_put_request(struct netfs_io_request *rreq, bool was_async)

void netfs_put_request(struct netfs_io_request *rreq, bool was_async,

		       enum netfs_rreq_ref_trace what)

{

	if (refcount_dec_and_test(&rreq->usage)) {

	unsigned int debug_id = rreq->debug_id;

	bool dead;

	int r;



	dead = __refcount_dec_and_test(&rreq->ref, &r);

	trace_netfs_rreq_ref(debug_id, r - 1, what);

	if (dead) {

		if (was_async) {

			rreq->work.func = netfs_free_request;

			if (!queue_work(system_unbound_wq, &rreq->work))
@@ -93,7 +103,7 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq 
		INIT_LIST_HEAD(&subreq->rreq_link);

		refcount_set(&subreq->usage, 2);

		subreq->rreq = rreq;

		netfs_get_request(rreq);

		netfs_get_request(rreq, netfs_rreq_trace_get_subreq);

		netfs_stat(&netfs_n_rh_sreq);

	}
@@ -113,7 +123,7 @@ static void __netfs_put_subrequest(struct netfs_io_subrequest *subreq, 
	trace_netfs_sreq(subreq, netfs_sreq_trace_free);

	kfree(subreq);

	netfs_stat_d(&netfs_n_rh_sreq);

	netfs_put_request(rreq, was_async);

	netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);

}



void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async)

fs/netfs/read_helper.c

+7 −7
Original line number Diff line number Diff line
@@ -109,7 +109,7 @@ static void netfs_rreq_completed(struct netfs_io_request *rreq, bool was_async) 
{

	trace_netfs_rreq(rreq, netfs_rreq_trace_done);

	netfs_clear_subrequests(rreq, was_async);

	netfs_put_request(rreq, was_async);

	netfs_put_request(rreq, was_async, netfs_rreq_trace_put_complete);

}



/*
@@ -799,7 +799,7 @@ void netfs_readahead(struct readahead_control *ractl, 
	return;



cleanup_free:

	netfs_put_request(rreq, false);

	netfs_put_request(rreq, false, netfs_rreq_trace_put_failed);

	return;

cleanup:

	if (netfs_priv)
@@ -858,7 +858,7 @@ int netfs_readpage(struct file *file, 
	netfs_stat(&netfs_n_rh_readpage);

	trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);



	netfs_get_request(rreq);

	netfs_get_request(rreq, netfs_rreq_trace_get_hold);



	atomic_set(&rreq->nr_outstanding, 1);

	do {
@@ -883,7 +883,7 @@ int netfs_readpage(struct file *file, 
		ret = -EIO;

	}

out:

	netfs_put_request(rreq, false);

	netfs_put_request(rreq, false, netfs_rreq_trace_put_hold);

	return ret;

}

EXPORT_SYMBOL(netfs_readpage);
@@ -1030,13 +1030,13 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, 
	 */

	ractl._nr_pages = folio_nr_pages(folio);

	netfs_rreq_expand(rreq, &ractl);

	netfs_get_request(rreq);



	/* We hold the folio locks, so we can drop the references */

	folio_get(folio);

	while (readahead_folio(&ractl))

		;



	netfs_get_request(rreq, netfs_rreq_trace_get_hold);

	atomic_set(&rreq->nr_outstanding, 1);

	do {

		if (!netfs_rreq_submit_slice(rreq, &debug_index))
@@ -1062,7 +1062,7 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, 
		trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_write_begin);

		ret = -EIO;

	}

	netfs_put_request(rreq, false);

	netfs_put_request(rreq, false, netfs_rreq_trace_put_hold);

	if (ret < 0)

		goto error;
@@ -1078,7 +1078,7 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, 
	return 0;



error_put:

	netfs_put_request(rreq, false);

	netfs_put_request(rreq, false, netfs_rreq_trace_put_failed);

error:

	folio_unlock(folio);

	folio_put(folio);

include/linux/netfs.h

+1 −1
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ struct netfs_io_request { 
	loff_t			i_size;		/* Size of the file */

	loff_t			start;		/* Start position */

	pgoff_t			no_unlock_folio; /* Don't unlock this folio after read */

	refcount_t		usage;

	refcount_t		ref;

	unsigned long		flags;

#define NETFS_RREQ_INCOMPLETE_IO	0	/* Some ioreqs terminated short or with error */

#define NETFS_RREQ_COPY_TO_CACHE	1	/* Need to write to the cache */

include/trace/events/netfs.h

+35 −0
Original line number Diff line number Diff line
@@ -55,6 +55,15 @@ 
	EM(netfs_fail_short_write_begin,	"short-write-begin")	\

	E_(netfs_fail_prepare_write,		"prep-write")



#define netfs_rreq_ref_traces					\

	EM(netfs_rreq_trace_get_hold,		"GET HOLD   ")	\

	EM(netfs_rreq_trace_get_subreq,		"GET SUBREQ ")	\

	EM(netfs_rreq_trace_put_complete,	"PUT COMPLT ")	\

	EM(netfs_rreq_trace_put_failed,		"PUT FAILED ")	\

	EM(netfs_rreq_trace_put_hold,		"PUT HOLD   ")	\

	EM(netfs_rreq_trace_put_subreq,		"PUT SUBREQ ")	\

	E_(netfs_rreq_trace_new,		"NEW        ")



#ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY

#define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
@@ -67,6 +76,7 @@ enum netfs_read_trace { netfs_read_traces } __mode(byte); 
enum netfs_rreq_trace { netfs_rreq_traces } __mode(byte);

enum netfs_sreq_trace { netfs_sreq_traces } __mode(byte);

enum netfs_failure { netfs_failures } __mode(byte);

enum netfs_rreq_ref_trace { netfs_rreq_ref_traces } __mode(byte);



#endif
@@ -83,6 +93,7 @@ netfs_rreq_traces; 
netfs_sreq_sources;

netfs_sreq_traces;

netfs_failures;

netfs_rreq_ref_traces;



/*

 * Now redefine the EM() and E_() macros to map the enums to the strings that
@@ -229,6 +240,30 @@ TRACE_EVENT(netfs_failure, 
		      __entry->error)

	    );



TRACE_EVENT(netfs_rreq_ref,

	    TP_PROTO(unsigned int rreq_debug_id, int ref,

		     enum netfs_rreq_ref_trace what),



	    TP_ARGS(rreq_debug_id, ref, what),



	    TP_STRUCT__entry(

		    __field(unsigned int,		rreq		)

		    __field(int,			ref		)

		    __field(enum netfs_rreq_ref_trace,	what		)

			     ),



	    TP_fast_assign(

		    __entry->rreq	= rreq_debug_id;

		    __entry->ref	= ref;

		    __entry->what	= what;

			   ),



	    TP_printk("R=%08x %s r=%u",

		      __entry->rreq,

		      __print_symbolic(__entry->what, netfs_rreq_ref_traces),

		      __entry->ref)

	    );



#undef EM

#undef E_

#endif /* _TRACE_NETFS_H */