[Devel] [RH7 PATCH 1/6] ploop: generalize post_submit stage

[Dmitry Monakhov]

Currently post_submit() used only for convert_unwritten_extents.
But post_submit() is good transition point where all submitted
data was completed by lower layer, and new state about to be processed.
Iyt is ideal point where we can perform transition actions
For example:
 io_direct: Convert unwritten extents
 io_direct: issue empty barrier bio in order to simulate postflush
 io_direct,io_kaio: queue to fsync queue
 Etc.

This patch does not change anything, but prepare post_submit for
more logic which will be added later.

Signed-off-by: Dmitry Monakhov <dmonakhov at openvz.org>
---
 drivers/block/ploop/dev.c       | 10 ++++++----
 drivers/block/ploop/io_direct.c | 15 ++++++++++++---
 include/linux/ploop/ploop.h     | 12 +++++++++++-
 3 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
index e405232..e8b0304 100644
--- a/drivers/block/ploop/dev.c
+++ b/drivers/block/ploop/dev.c
@@ -2351,10 +2351,12 @@ static void ploop_req_state_process(struct ploop_request * preq)
 		preq->prealloc_size = 0; /* only for sanity */
 	}
 
-	if (test_bit(PLOOP_REQ_POST_SUBMIT, &preq->state)) {
-		preq->eng_io->ops->post_submit(preq->eng_io, preq);
-		clear_bit(PLOOP_REQ_POST_SUBMIT, &preq->state);
+	if (test_and_clear_bit(PLOOP_REQ_POST_SUBMIT, &preq->state)) {
+		struct ploop_io *io = preq->eng_io;
+
 		preq->eng_io = NULL;
+		if (preq->eng_io->ops->post_submit(io, preq))
+			goto out;
 	}
 
 restart:
@@ -2633,7 +2635,7 @@ restart:
 	default:
 		BUG();
 	}
-
+out:
 	if (release_ioc) {
 		struct io_context * ioc = current->io_context;
 		current->io_context = saved_ioc;
diff --git a/drivers/block/ploop/io_direct.c b/drivers/block/ploop/io_direct.c
index f1812fe..ec905b4 100644
--- a/drivers/block/ploop/io_direct.c
+++ b/drivers/block/ploop/io_direct.c
@@ -416,8 +416,8 @@ try_again:
 		}
 
 		preq->iblock = iblk;
-		preq->eng_io = io;
-		set_bit(PLOOP_REQ_POST_SUBMIT, &preq->state);
+		set_bit(PLOOP_REQ_DEL_CONV, &preq->state);
+		ploop_add_post_submit(io, preq);
 		dio_submit_pad(io, preq, sbl, size, em);
 		err = 0;
 		goto end_write;
@@ -501,7 +501,7 @@ end_write:
 }
 
 static void
-dio_post_submit(struct ploop_io *io, struct ploop_request * preq)
+dio_convert_extent(struct ploop_io *io, struct ploop_request * preq)
 {
 	struct ploop_device *plo = preq->plo;
 	sector_t sec = (sector_t)preq->iblock << preq->plo->cluster_log;
@@ -540,6 +540,15 @@ dio_post_submit(struct ploop_io *io, struct ploop_request * preq)
 	}
 }
 
+static int
+dio_post_submit(struct ploop_io *io, struct ploop_request * preq)
+{
+	if (test_and_clear_bit(PLOOP_REQ_DEL_CONV, &preq->state))
+		dio_convert_extent(io, preq);
+
+	return 0;
+}
+
 /* Submit the whole cluster. If preq contains only partial data
  * within the cluster, pad the rest of cluster with zeros.
  */
diff --git a/include/linux/ploop/ploop.h b/include/linux/ploop/ploop.h
index 0fba25e..4c52a40 100644
--- a/include/linux/ploop/ploop.h
+++ b/include/linux/ploop/ploop.h
@@ -148,7 +148,7 @@ struct ploop_io_ops
 			  struct bio_list *sbl, iblock_t iblk, unsigned int size);
 	void	(*submit_alloc)(struct ploop_io *, struct ploop_request *,
 				struct bio_list *sbl, unsigned int size);
-	void	(*post_submit)(struct ploop_io *, struct ploop_request *);
+	int (*post_submit)(struct ploop_io *, struct ploop_request *);
 
 	int	(*disable_merge)(struct ploop_io * io, sector_t isector, unsigned int len);
 	int	(*fastmap)(struct ploop_io * io, struct bio *orig_bio,
@@ -471,6 +471,7 @@ enum
 	PLOOP_REQ_POST_SUBMIT, /* preq needs post_submit processing */
 	PLOOP_REQ_PUSH_BACKUP, /* preq was ACKed by userspace push_backup */
 	PLOOP_REQ_ALLOW_READS, /* READs are allowed for given req_cluster */
+	PLOOP_REQ_DEL_CONV,    /* post_submit: conversion required */
 	PLOOP_REQ_FSYNC_DONE,  /* fsync_thread() performed f_op->fsync() */
 };
 
@@ -479,6 +480,8 @@ enum
 #define PLOOP_REQ_RELOC_S_FL (1 << PLOOP_REQ_RELOC_S)
 #define PLOOP_REQ_DISCARD_FL (1 << PLOOP_REQ_DISCARD)
 #define PLOOP_REQ_ZERO_FL (1 << PLOOP_REQ_ZERO)
+#define PLOOP_REQ_POST_SUBMIT_FL (1 << PLOOP_REQ_POST_SUBMIT)
+#define PLOOP_REQ_DEL_CONV_FL (1 << PLOOP_REQ_DEL_CONV)
 
 enum
 {
@@ -767,6 +770,13 @@ static inline void ploop_entry_qlen_dec(struct ploop_request * preq)
 		preq->plo->read_sync_reqs--;
 	}
 }
+static inline
+void ploop_add_post_submit(struct ploop_io *io, struct ploop_request * preq)
+{
+	BUG_ON(preq->eng_io && preq->eng_io != io);
+	preq->eng_io = io;
+	set_bit(PLOOP_REQ_POST_SUBMIT, &preq->state);
+}
 
 static inline int ploop_map_log(struct ploop_device *plo)
 {
-- 
1.8.3.1