Merge tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull netfs updates from David Howells:
 "Netfs prep for write helpers.

  Having had a go at implementing write helpers and content encryption
  support in netfslib, it seems that the netfs_read_{,sub}request
  structs and the equivalent write request structs were almost the same
  and so should be merged, thereby requiring only one set of
  alloc/get/put functions and a common set of tracepoints.

  Merging the structs also has the advantage that if a bounce buffer is
  added to the request struct, a read operation can be performed to fill
  the bounce buffer, the contents of the buffer can be modified and then
  a write operation can be performed on it to send the data wherever it
  needs to go using the same request structure all the way through. The
  I/O handlers would then transparently perform any required crypto.
  This should make it easier to perform RMW cycles if needed.

  The potentially common functions and structs, however, by their names
  all proclaim themselves to be associated with the read side of things.

  The bulk of these changes alter this in the following ways:

   - Rename struct netfs_read_{,sub}request to netfs_io_{,sub}request.

   - Rename some enums, members and flags to make them more appropriate.

   - Adjust some comments to match.

   - Drop "read"/"rreq" from the names of common functions. For
     instance, netfs_get_read_request() becomes netfs_get_request().

   - The ->init_rreq() and ->issue_op() methods become ->init_request()
     and ->issue_read(). I've kept the latter as a read-specific
     function and in another branch added an ->issue_write() method.

  The driver source is then reorganised into a number of files:

        fs/netfs/buffered_read.c        Create read reqs to the pagecache
        fs/netfs/io.c                   Dispatchers for read and write reqs
        fs/netfs/main.c                 Some general miscellaneous bits
        fs/netfs/objects.c              Alloc, get and put functions
        fs/netfs/stats.c                Optional procfs statistics.

  and future development can be fitted into this scheme, e.g.:

        fs/netfs/buffered_write.c       Modify the pagecache
        fs/netfs/buffered_flush.c       Writeback from the pagecache
        fs/netfs/direct_read.c          DIO read support
        fs/netfs/direct_write.c         DIO write support
        fs/netfs/unbuffered_write.c     Write modifications directly back

  Beyond the above changes, there are also some changes that affect how
  things work:

   - Make fscache_end_operation() generally available.

   - In the netfs tracing header, generate enums from the symbol ->
     string mapping tables rather than manually coding them.

   - Add a struct for filesystems that uses netfslib to put into their
     inode wrapper structs to hold extra state that netfslib is
     interested in, such as the fscache cookie. This allows netfslib
     functions to be set in filesystem operation tables and jumped to
     directly without having to have a filesystem wrapper.

   - Add a member to the struct added above to track the remote inode
     length as that may differ if local modifications are buffered. We
     may need to supply an appropriate EOF pointer when storing data (in
     AFS for example).

   - Pass extra information to netfs_alloc_request() so that the
     ->init_request() hook can access it and retain information to
     indicate the origin of the operation.

   - Make the ->init_request() hook return an error, thereby allowing a
     filesystem that isn't allowed to cache an inode (ceph or cifs, for
     example) to skip readahead.

   - Switch to using refcount_t for subrequests and add tracepoints to
     log refcount changes for the request and subrequest structs.

   - Add a function to consolidate dispatching a read request. Similar
     code is used in three places and another couple are likely to be
     added in the future"

Link: https://lore.kernel.org/all/2639515.1648483225@warthog.procyon.org.uk/

* tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Maintain netfs_i_context::remote_i_size
  netfs: Keep track of the actual remote file size
  netfs: Split some core bits out into their own file
  netfs: Split fs/netfs/read_helper.c
  netfs: Rename read_helper.c to io.c
  netfs: Prepare to split read_helper.c
  netfs: Add a function to consolidate beginning a read
  netfs: Add a netfs inode context
  ceph: Make ceph_init_request() check caps on readahead
  netfs: Change ->init_request() to return an error code
  netfs: Refactor arguments for netfs_alloc_read_request
  netfs: Adjust the netfs_failure tracepoint to indicate non-subreq lines
  netfs: Trace refcounting on the netfs_io_subrequest struct
  netfs: Trace refcounting on the netfs_io_request struct
  netfs: Adjust the netfs_rreq tracepoint slightly
  netfs: Split netfs_io_* object handling out
  netfs: Finish off rename of netfs_read_request to netfs_io_request
  netfs: Rename netfs_read_*request to netfs_io_*request
  netfs: Generate enums from trace symbol mapping lists
  fscache: export fscache_end_operation()

4 files changed, 266 insertions, 106 deletions

diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index d44ff747a657..6727fb0db619 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -457,6 +457,20 @@ int fscache_begin_read_operation(struct netfs_cache_resources *cres,
 }
 
 /**
+ * fscache_end_operation - End the read operation for the netfs lib
+ * @cres: The cache resources for the read operation
+ *
+ * Clean up the resources at the end of the read request.
+ */
+static inline void fscache_end_operation(struct netfs_cache_resources *cres)
+{
+	const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
+
+	if (ops)
+		ops->end_operation(cres);
+}
+
+/**
  * fscache_read - Start a read from the cache.
  * @cres: The cache resources to use
  * @start_pos: The beginning file offset in the cache file
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 614f22213e21..c7bf1eaf51d5 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -18,6 +18,8 @@
 #include <linux/fs.h>
 #include <linux/pagemap.h>
 
+enum netfs_sreq_ref_trace;
+
 /*
  * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
  * a page is currently backed by a local disk cache
@@ -106,7 +108,7 @@ static inline int wait_on_page_fscache_killable(struct page *page)
 	return folio_wait_private_2_killable(page_folio(page));
 }
 
-enum netfs_read_source {
+enum netfs_io_source {
 	NETFS_FILL_WITH_ZEROES,
 	NETFS_DOWNLOAD_FROM_SERVER,
 	NETFS_READ_FROM_CACHE,
@@ -117,6 +119,17 @@ typedef void (*netfs_io_terminated_t)(void *priv, ssize_t transferred_or_error,
 				      bool was_async);
 
 /*
+ * Per-inode description.  This must be directly after the inode struct.
+ */
+struct netfs_i_context {
+	const struct netfs_request_ops *ops;
+#if IS_ENABLED(CONFIG_FSCACHE)
+	struct fscache_cookie	*cache;
+#endif
+	loff_t			remote_i_size;	/* Size of the remote file */
+};
+
+/*
  * Resources required to do operations on a cache.
  */
 struct netfs_cache_resources {
@@ -130,69 +143,75 @@ struct netfs_cache_resources {
 /*
  * Descriptor for a single component subrequest.
  */
-struct netfs_read_subrequest {
-	struct netfs_read_request *rreq;	/* Supervising read request */
+struct netfs_io_subrequest {
+	struct netfs_io_request *rreq;		/* Supervising I/O request */
 	struct list_head	rreq_link;	/* Link in rreq->subrequests */
 	loff_t			start;		/* Where to start the I/O */
 	size_t			len;		/* Size of the I/O */
 	size_t			transferred;	/* Amount of data transferred */
-	refcount_t		usage;
+	refcount_t		ref;
 	short			error;		/* 0 or error that occurred */
 	unsigned short		debug_index;	/* Index in list (for debugging output) */
-	enum netfs_read_source	source;		/* Where to read from */
+	enum netfs_io_source	source;		/* Where to read from/write to */
 	unsigned long		flags;
-#define NETFS_SREQ_WRITE_TO_CACHE	0	/* Set if should write to cache */
+#define NETFS_SREQ_COPY_TO_CACHE	0	/* Set if should copy the data to the cache */
 #define NETFS_SREQ_CLEAR_TAIL		1	/* Set if the rest of the read should be cleared */
-#define NETFS_SREQ_SHORT_READ		2	/* Set if there was a short read from the cache */
+#define NETFS_SREQ_SHORT_IO		2	/* Set if the I/O was short */
 #define NETFS_SREQ_SEEK_DATA_READ	3	/* Set if ->read() should SEEK_DATA first */
 #define NETFS_SREQ_NO_PROGRESS		4	/* Set if we didn't manage to read any data */
 };
 
+enum netfs_io_origin {
+	NETFS_READAHEAD,		/* This read was triggered by readahead */
+	NETFS_READPAGE,			/* This read is a synchronous read */
+	NETFS_READ_FOR_WRITE,		/* This read is to prepare a write */
+} __mode(byte);
+
 /*
- * Descriptor for a read helper request.  This is used to make multiple I/O
- * requests on a variety of sources and then stitch the result together.
+ * Descriptor for an I/O helper request.  This is used to make multiple I/O
+ * operations to a variety of data stores and then stitch the result together.
  */
-struct netfs_read_request {
+struct netfs_io_request {
 	struct work_struct	work;
 	struct inode		*inode;		/* The file being accessed */
 	struct address_space	*mapping;	/* The mapping being accessed */
 	struct netfs_cache_resources cache_resources;
-	struct list_head	subrequests;	/* Requests to fetch I/O from disk or net */
+	struct list_head	subrequests;	/* Contributory I/O operations */
 	void			*netfs_priv;	/* Private data for the netfs */
 	unsigned int		debug_id;
-	atomic_t		nr_rd_ops;	/* Number of read ops in progress */
-	atomic_t		nr_wr_ops;	/* Number of write ops in progress */
+	atomic_t		nr_outstanding;	/* Number of ops in progress */
+	atomic_t		nr_copy_ops;	/* Number of copy-to-cache ops in progress */
 	size_t			submitted;	/* Amount submitted for I/O so far */
 	size_t			len;		/* Length of the request */
 	short			error;		/* 0 or error that occurred */
+	enum netfs_io_origin	origin;		/* Origin of the 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_WRITE_TO_CACHE	1	/* Need to write to the cache */
+#define NETFS_RREQ_COPY_TO_CACHE	1	/* Need to write to the cache */
 #define NETFS_RREQ_NO_UNLOCK_FOLIO	2	/* Don't unlock no_unlock_folio on completion */
 #define NETFS_RREQ_DONT_UNLOCK_FOLIOS	3	/* Don't unlock the folios on completion */
 #define NETFS_RREQ_FAILED		4	/* The request failed */
 #define NETFS_RREQ_IN_PROGRESS		5	/* Unlocked when the request completes */
-	const struct netfs_read_request_ops *netfs_ops;
+	const struct netfs_request_ops *netfs_ops;
 };
 
 /*
  * Operations the network filesystem can/must provide to the helpers.
  */
-struct netfs_read_request_ops {
-	bool (*is_cache_enabled)(struct inode *inode);
-	void (*init_rreq)(struct netfs_read_request *rreq, struct file *file);
-	int (*begin_cache_operation)(struct netfs_read_request *rreq);
-	void (*expand_readahead)(struct netfs_read_request *rreq);
-	bool (*clamp_length)(struct netfs_read_subrequest *subreq);
-	void (*issue_op)(struct netfs_read_subrequest *subreq);
-	bool (*is_still_valid)(struct netfs_read_request *rreq);
+struct netfs_request_ops {
+	int (*init_request)(struct netfs_io_request *rreq, struct file *file);
+	int (*begin_cache_operation)(struct netfs_io_request *rreq);
+	void (*expand_readahead)(struct netfs_io_request *rreq);
+	bool (*clamp_length)(struct netfs_io_subrequest *subreq);
+	void (*issue_read)(struct netfs_io_subrequest *subreq);
+	bool (*is_still_valid)(struct netfs_io_request *rreq);
 	int (*check_write_begin)(struct file *file, loff_t pos, unsigned len,
 				 struct folio *folio, void **_fsdata);
-	void (*done)(struct netfs_read_request *rreq);
+	void (*done)(struct netfs_io_request *rreq);
 	void (*cleanup)(struct address_space *mapping, void *netfs_priv);
 };
 
@@ -235,7 +254,7 @@ struct netfs_cache_ops {
 	/* Prepare a read operation, shortening it to a cached/uncached
 	 * boundary as appropriate.
 	 */
-	enum netfs_read_source (*prepare_read)(struct netfs_read_subrequest *subreq,
+	enum netfs_io_source (*prepare_read)(struct netfs_io_subrequest *subreq,
 					       loff_t i_size);
 
 	/* Prepare a write operation, working out what part of the write we can
@@ -254,20 +273,89 @@ struct netfs_cache_ops {
 };
 
 struct readahead_control;
-extern void netfs_readahead(struct readahead_control *,
-			    const struct netfs_read_request_ops *,
-			    void *);
-extern int netfs_readpage(struct file *,
-			  struct folio *,
-			  const struct netfs_read_request_ops *,
-			  void *);
+extern void netfs_readahead(struct readahead_control *);
+extern int netfs_readpage(struct file *, struct page *);
 extern int netfs_write_begin(struct file *, struct address_space *,
 			     loff_t, unsigned int, unsigned int, struct folio **,
-			     void **,
-			     const struct netfs_read_request_ops *,
-			     void *);
+			     void **);
 
-extern void netfs_subreq_terminated(struct netfs_read_subrequest *, ssize_t, bool);
+extern void netfs_subreq_terminated(struct netfs_io_subrequest *, ssize_t, bool);
+extern void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
+				 enum netfs_sreq_ref_trace what);
+extern void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
+				 bool was_async, enum netfs_sreq_ref_trace what);
 extern void netfs_stats_show(struct seq_file *);
 
+/**
+ * netfs_i_context - Get the netfs inode context from the inode
+ * @inode: The inode to query
+ *
+ * Get the netfs lib inode context from the network filesystem's inode.  The
+ * context struct is expected to directly follow on from the VFS inode struct.
+ */
+static inline struct netfs_i_context *netfs_i_context(struct inode *inode)
+{
+	return (struct netfs_i_context *)(inode + 1);
+}
+
+/**
+ * netfs_inode - Get the netfs inode from the inode context
+ * @ctx: The context to query
+ *
+ * Get the netfs inode from the netfs library's inode context.  The VFS inode
+ * is expected to directly precede the context struct.
+ */
+static inline struct inode *netfs_inode(struct netfs_i_context *ctx)
+{
+	return ((struct inode *)ctx) - 1;
+}
+
+/**
+ * netfs_i_context_init - Initialise a netfs lib context
+ * @inode: The inode with which the context is associated
+ * @ops: The netfs's operations list
+ *
+ * Initialise the netfs library context struct.  This is expected to follow on
+ * directly from the VFS inode struct.
+ */
+static inline void netfs_i_context_init(struct inode *inode,
+					const struct netfs_request_ops *ops)
+{
+	struct netfs_i_context *ctx = netfs_i_context(inode);
+
+	memset(ctx, 0, sizeof(*ctx));
+	ctx->ops = ops;
+	ctx->remote_i_size = i_size_read(inode);
+}
+
+/**
+ * netfs_resize_file - Note that a file got resized
+ * @inode: The inode being resized
+ * @new_i_size: The new file size
+ *
+ * Inform the netfs lib that a file got resized so that it can adjust its state.
+ */
+static inline void netfs_resize_file(struct inode *inode, loff_t new_i_size)
+{
+	struct netfs_i_context *ctx = netfs_i_context(inode);
+
+	ctx->remote_i_size = new_i_size;
+}
+
+/**
+ * netfs_i_cookie - Get the cache cookie from the inode
+ * @inode: The inode to query
+ *
+ * Get the caching cookie (if enabled) from the network filesystem's inode.
+ */
+static inline struct fscache_cookie *netfs_i_cookie(struct inode *inode)
+{
+#if IS_ENABLED(CONFIG_FSCACHE)
+	struct netfs_i_context *ctx = netfs_i_context(inode);
+	return ctx->cache;
+#else
+	return NULL;
+#endif
+}
+
 #endif /* _LINUX_NETFS_H */
diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
index 2c530637e10a..311c14a20e70 100644
--- a/include/trace/events/cachefiles.h
+++ b/include/trace/events/cachefiles.h
@@ -426,8 +426,8 @@ TRACE_EVENT(cachefiles_vol_coherency,
 	    );
 
 TRACE_EVENT(cachefiles_prep_read,
-	    TP_PROTO(struct netfs_read_subrequest *sreq,
-		     enum netfs_read_source source,
+	    TP_PROTO(struct netfs_io_subrequest *sreq,
+		     enum netfs_io_source source,
 		     enum cachefiles_prepare_read_trace why,
 		     ino_t cache_inode),
 
@@ -437,7 +437,7 @@ TRACE_EVENT(cachefiles_prep_read,
 		    __field(unsigned int,		rreq		)
 		    __field(unsigned short,		index		)
 		    __field(unsigned short,		flags		)
-		    __field(enum netfs_read_source,	source		)
+		    __field(enum netfs_io_source,	source		)
 		    __field(enum cachefiles_prepare_read_trace,	why	)
 		    __field(size_t,			len		)
 		    __field(loff_t,			start		)
diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h
index e6f4ebbb4c69..beec534cbaab 100644
--- a/include/trace/events/netfs.h
+++ b/include/trace/events/netfs.h
@@ -15,63 +15,25 @@
 /*
  * Define enums for tracing information.
  */
-#ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
-#define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
-
-enum netfs_read_trace {
-	netfs_read_trace_expanded,
-	netfs_read_trace_readahead,
-	netfs_read_trace_readpage,
-	netfs_read_trace_write_begin,
-};
-
-enum netfs_rreq_trace {
-	netfs_rreq_trace_assess,
-	netfs_rreq_trace_done,
-	netfs_rreq_trace_free,
-	netfs_rreq_trace_resubmit,
-	netfs_rreq_trace_unlock,
-	netfs_rreq_trace_unmark,
-	netfs_rreq_trace_write,
-};
-
-enum netfs_sreq_trace {
-	netfs_sreq_trace_download_instead,
-	netfs_sreq_trace_free,
-	netfs_sreq_trace_prepare,
-	netfs_sreq_trace_resubmit_short,
-	netfs_sreq_trace_submit,
-	netfs_sreq_trace_terminated,
-	netfs_sreq_trace_write,
-	netfs_sreq_trace_write_skip,
-	netfs_sreq_trace_write_term,
-};
-
-enum netfs_failure {
-	netfs_fail_check_write_begin,
-	netfs_fail_copy_to_cache,
-	netfs_fail_read,
-	netfs_fail_short_readpage,
-	netfs_fail_short_write_begin,
-	netfs_fail_prepare_write,
-};
-
-#endif
-
 #define netfs_read_traces					\
 	EM(netfs_read_trace_expanded,		"EXPANDED ")	\
 	EM(netfs_read_trace_readahead,		"READAHEAD")	\
 	EM(netfs_read_trace_readpage,		"READPAGE ")	\
 	E_(netfs_read_trace_write_begin,	"WRITEBEGN")
 
+#define netfs_rreq_origins					\
+	EM(NETFS_READAHEAD,			"RA")		\
+	EM(NETFS_READPAGE,			"RP")		\
+	E_(NETFS_READ_FOR_WRITE,		"RW")
+
 #define netfs_rreq_traces					\
-	EM(netfs_rreq_trace_assess,		"ASSESS")	\
-	EM(netfs_rreq_trace_done,		"DONE  ")	\
-	EM(netfs_rreq_trace_free,		"FREE  ")	\
-	EM(netfs_rreq_trace_resubmit,		"RESUBM")	\
-	EM(netfs_rreq_trace_unlock,		"UNLOCK")	\
-	EM(netfs_rreq_trace_unmark,		"UNMARK")	\
-	E_(netfs_rreq_trace_write,		"WRITE ")
+	EM(netfs_rreq_trace_assess,		"ASSESS ")	\
+	EM(netfs_rreq_trace_copy,		"COPY   ")	\
+	EM(netfs_rreq_trace_done,		"DONE   ")	\
+	EM(netfs_rreq_trace_free,		"FREE   ")	\
+	EM(netfs_rreq_trace_resubmit,		"RESUBMT")	\
+	EM(netfs_rreq_trace_unlock,		"UNLOCK ")	\
+	E_(netfs_rreq_trace_unmark,		"UNMARK ")
 
 #define netfs_sreq_sources					\
 	EM(NETFS_FILL_WITH_ZEROES,		"ZERO")		\
@@ -94,10 +56,47 @@ enum netfs_failure {
 	EM(netfs_fail_check_write_begin,	"check-write-begin")	\
 	EM(netfs_fail_copy_to_cache,		"copy-to-cache")	\
 	EM(netfs_fail_read,			"read")			\
-	EM(netfs_fail_short_readpage,		"short-readpage")	\
-	EM(netfs_fail_short_write_begin,	"short-write-begin")	\
+	EM(netfs_fail_short_read,		"short-read")		\
 	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_discard,	"PUT DISCARD")	\
+	EM(netfs_rreq_trace_put_failed,		"PUT FAILED ")	\
+	EM(netfs_rreq_trace_put_hold,		"PUT HOLD   ")	\
+	EM(netfs_rreq_trace_put_subreq,		"PUT SUBREQ ")	\
+	EM(netfs_rreq_trace_put_zero_len,	"PUT ZEROLEN")	\
+	E_(netfs_rreq_trace_new,		"NEW        ")
+
+#define netfs_sreq_ref_traces					\
+	EM(netfs_sreq_trace_get_copy_to_cache,	"GET COPY2C ")	\
+	EM(netfs_sreq_trace_get_resubmit,	"GET RESUBMIT")	\
+	EM(netfs_sreq_trace_get_short_read,	"GET SHORTRD")	\
+	EM(netfs_sreq_trace_new,		"NEW        ")	\
+	EM(netfs_sreq_trace_put_clear,		"PUT CLEAR  ")	\
+	EM(netfs_sreq_trace_put_failed,		"PUT FAILED ")	\
+	EM(netfs_sreq_trace_put_merged,		"PUT MERGED ")	\
+	EM(netfs_sreq_trace_put_no_copy,	"PUT NO COPY")	\
+	E_(netfs_sreq_trace_put_terminated,	"PUT TERM   ")
+
+#ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
+#define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
+
+#undef EM
+#undef E_
+#define EM(a, b) a,
+#define E_(a, b) a
+
+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);
+enum netfs_sreq_ref_trace { netfs_sreq_ref_traces } __mode(byte);
+
+#endif
 
 /*
  * Export enum symbols via userspace.
@@ -108,10 +107,13 @@ enum netfs_failure {
 #define E_(a, b) TRACE_DEFINE_ENUM(a);
 
 netfs_read_traces;
+netfs_rreq_origins;
 netfs_rreq_traces;
 netfs_sreq_sources;
 netfs_sreq_traces;
 netfs_failures;
+netfs_rreq_ref_traces;
+netfs_sreq_ref_traces;
 
 /*
  * Now redefine the EM() and E_() macros to map the enums to the strings that
@@ -123,7 +125,7 @@ netfs_failures;
 #define E_(a, b)	{ a, b }
 
 TRACE_EVENT(netfs_read,
-	    TP_PROTO(struct netfs_read_request *rreq,
+	    TP_PROTO(struct netfs_io_request *rreq,
 		     loff_t start, size_t len,
 		     enum netfs_read_trace what),
 
@@ -156,31 +158,34 @@ TRACE_EVENT(netfs_read,
 	    );
 
 TRACE_EVENT(netfs_rreq,
-	    TP_PROTO(struct netfs_read_request *rreq,
+	    TP_PROTO(struct netfs_io_request *rreq,
 		     enum netfs_rreq_trace what),
 
 	    TP_ARGS(rreq, what),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		rreq		)
-		    __field(unsigned short,		flags		)
+		    __field(unsigned int,		flags		)
+		    __field(enum netfs_io_origin,	origin		)
 		    __field(enum netfs_rreq_trace,	what		)
 			     ),
 
 	    TP_fast_assign(
 		    __entry->rreq	= rreq->debug_id;
 		    __entry->flags	= rreq->flags;
+		    __entry->origin	= rreq->origin;
 		    __entry->what	= what;
 			   ),
 
-	    TP_printk("R=%08x %s f=%02x",
+	    TP_printk("R=%08x %s %s f=%02x",
 		      __entry->rreq,
+		      __print_symbolic(__entry->origin, netfs_rreq_origins),
 		      __print_symbolic(__entry->what, netfs_rreq_traces),
 		      __entry->flags)
 	    );
 
 TRACE_EVENT(netfs_sreq,
-	    TP_PROTO(struct netfs_read_subrequest *sreq,
+	    TP_PROTO(struct netfs_io_subrequest *sreq,
 		     enum netfs_sreq_trace what),
 
 	    TP_ARGS(sreq, what),
@@ -190,7 +195,7 @@ TRACE_EVENT(netfs_sreq,
 		    __field(unsigned short,		index		)
 		    __field(short,			error		)
 		    __field(unsigned short,		flags		)
-		    __field(enum netfs_read_source,	source		)
+		    __field(enum netfs_io_source,	source		)
 		    __field(enum netfs_sreq_trace,	what		)
 		    __field(size_t,			len		)
 		    __field(size_t,			transferred	)
@@ -211,26 +216,26 @@ TRACE_EVENT(netfs_sreq,
 
 	    TP_printk("R=%08x[%u] %s %s f=%02x s=%llx %zx/%zx e=%d",
 		      __entry->rreq, __entry->index,
-		      __print_symbolic(__entry->what, netfs_sreq_traces),
 		      __print_symbolic(__entry->source, netfs_sreq_sources),
+		      __print_symbolic(__entry->what, netfs_sreq_traces),
 		      __entry->flags,
 		      __entry->start, __entry->transferred, __entry->len,
 		      __entry->error)
 	    );
 
 TRACE_EVENT(netfs_failure,
-	    TP_PROTO(struct netfs_read_request *rreq,
-		     struct netfs_read_subrequest *sreq,
+	    TP_PROTO(struct netfs_io_request *rreq,
+		     struct netfs_io_subrequest *sreq,
 		     int error, enum netfs_failure what),
 
 	    TP_ARGS(rreq, sreq, error, what),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		rreq		)
-		    __field(unsigned short,		index		)
+		    __field(short,			index		)
 		    __field(short,			error		)
 		    __field(unsigned short,		flags		)
-		    __field(enum netfs_read_source,	source		)
+		    __field(enum netfs_io_source,	source		)
 		    __field(enum netfs_failure,		what		)
 		    __field(size_t,			len		)
 		    __field(size_t,			transferred	)
@@ -239,17 +244,17 @@ TRACE_EVENT(netfs_failure,
 
 	    TP_fast_assign(
 		    __entry->rreq	= rreq->debug_id;
-		    __entry->index	= sreq ? sreq->debug_index : 0;
+		    __entry->index	= sreq ? sreq->debug_index : -1;
 		    __entry->error	= error;
 		    __entry->flags	= sreq ? sreq->flags : 0;
 		    __entry->source	= sreq ? sreq->source : NETFS_INVALID_READ;
 		    __entry->what	= what;
-		    __entry->len	= sreq ? sreq->len : 0;
+		    __entry->len	= sreq ? sreq->len : rreq->len;
 		    __entry->transferred = sreq ? sreq->transferred : 0;
 		    __entry->start	= sreq ? sreq->start : 0;
 			   ),
 
-	    TP_printk("R=%08x[%u] %s f=%02x s=%llx %zx/%zx %s e=%d",
+	    TP_printk("R=%08x[%d] %s f=%02x s=%llx %zx/%zx %s e=%d",
 		      __entry->rreq, __entry->index,
 		      __print_symbolic(__entry->source, netfs_sreq_sources),
 		      __entry->flags,
@@ -258,6 +263,59 @@ 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)
+	    );
+
+TRACE_EVENT(netfs_sreq_ref,
+	    TP_PROTO(unsigned int rreq_debug_id, unsigned int subreq_debug_index,
+		     int ref, enum netfs_sreq_ref_trace what),
+
+	    TP_ARGS(rreq_debug_id, subreq_debug_index, ref, what),
+
+	    TP_STRUCT__entry(
+		    __field(unsigned int,		rreq		)
+		    __field(unsigned int,		subreq		)
+		    __field(int,			ref		)
+		    __field(enum netfs_sreq_ref_trace,	what		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->rreq	= rreq_debug_id;
+		    __entry->subreq	= subreq_debug_index;
+		    __entry->ref	= ref;
+		    __entry->what	= what;
+			   ),
+
+	    TP_printk("R=%08x[%x] %s r=%u",
+		      __entry->rreq,
+		      __entry->subreq,
+		      __print_symbolic(__entry->what, netfs_sreq_ref_traces),
+		      __entry->ref)
+	    );
+
+#undef EM
+#undef E_
 #endif /* _TRACE_NETFS_H */
 
 /* This part must be outside protection */