pnfs-obj: Get rid of objlayout_{alloc,free}_io_state

This is part of moving objio_osd to use the ORE.

objlayout_io_state had two functions:
1. It was used in the error reporting mechanism at layout_return.
   This function is kept intact.
   (Later patch will rename objlayout_io_state => objlayout_io_res)
2. Carrier of rw io members into the objio_read/write_paglist API.
   This is removed in this patch.

The {r,w}data received from NFS are passed directly to the
objio_{read,write}_paglist API. The io_engine is now allocating
it's own IO state as part of the read/write. The minimal
functionality that was part of the generic allocation is passed
to the io_engine.

So part of this patch is rename of:
	ios->ol_state.foo => ios->foo

At objlayout_{read,write}_done an objlayout_io_state is passed that
denotes the result of the IO. (Hence the later name change).
If the IO is successful objlayout calls an objio_free_result() API
immediately (Which for objio_osd causes the release of the io_state).
If the IO ended in an error it is hanged onto until reported in
layout_return and is released later through the objio_free_result()
API. (All this is not new just renamed and cleaned)

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 112 insertions, 142 deletions

diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c
index 0c7c9ec24e6..48eb91aad55 100644
--- a/fs/nfs/objlayout/objio_osd.c
+++ b/fs/nfs/objlayout/objio_osd.c
@@ -148,6 +148,13 @@ struct objio_state {
 	/* Generic layer */
 	struct objlayout_io_state ol_state;
 
+	struct page **pages;
+	unsigned pgbase;
+	unsigned nr_pages;
+	unsigned long count;
+	loff_t offset;
+	bool sync;
+
 	struct objio_segment *layout;
 
 	struct kref kref;
@@ -394,30 +401,43 @@ void objio_free_lseg(struct pnfs_layout_segment *lseg)
 	kfree(objio_seg);
 }
 
-int objio_alloc_io_state(struct pnfs_layout_segment *lseg,
-			 struct objlayout_io_state **outp,
-			 gfp_t gfp_flags)
+static int
+objio_alloc_io_state(struct pnfs_layout_hdr *pnfs_layout_type,
+	struct pnfs_layout_segment *lseg, struct page **pages, unsigned pgbase,
+	loff_t offset, size_t count, void *rpcdata, gfp_t gfp_flags,
+	struct objio_state **outp)
 {
 	struct objio_segment *objio_seg = OBJIO_LSEG(lseg);
 	struct objio_state *ios;
-	const unsigned first_size = sizeof(*ios) +
-				objio_seg->num_comps * sizeof(ios->per_dev[0]);
-	const unsigned sec_size = objio_seg->num_comps *
-						sizeof(ios->ol_state.ioerrs[0]);
-
-	ios = kzalloc(first_size + sec_size, gfp_flags);
-	if (unlikely(!ios))
+	struct __alloc_objio_state {
+		struct objio_state objios;
+		struct _objio_per_comp per_dev[objio_seg->num_comps];
+		struct pnfs_osd_ioerr ioerrs[objio_seg->num_comps];
+	} *aos;
+
+	aos = kzalloc(sizeof(*aos), gfp_flags);
+	if (unlikely(!aos))
 		return -ENOMEM;
 
-	ios->layout = objio_seg;
-	ios->ol_state.ioerrs = ((void *)ios) + first_size;
-	ios->ol_state.num_comps = objio_seg->num_comps;
+	ios = &aos->objios;
 
-	*outp = &ios->ol_state;
+	ios->layout = objio_seg;
+	objlayout_init_ioerrs(&aos->objios.ol_state, objio_seg->num_comps,
+			aos->ioerrs, rpcdata, pnfs_layout_type);
+
+	ios->pages = pages;
+	ios->pgbase = pgbase;
+	ios->nr_pages = (pgbase + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	ios->offset = offset;
+	ios->count = count;
+	ios->sync = 0;
+	BUG_ON(ios->nr_pages > (pgbase + count + PAGE_SIZE - 1) >> PAGE_SHIFT);
+
+	*outp = ios;
 	return 0;
 }
 
-void objio_free_io_state(struct objlayout_io_state *ol_state)
+void objio_free_result(struct objlayout_io_state *ol_state)
 {
 	struct objio_state *ios = container_of(ol_state, struct objio_state,
 					       ol_state);
@@ -598,7 +618,7 @@ static int _add_stripe_unit(struct objio_state *ios,  unsigned *cur_pg,
 	if (per_dev->bio == NULL) {
 		unsigned pages_in_stripe = ios->layout->group_width *
 				      (ios->layout->stripe_unit / PAGE_SIZE);
-		unsigned bio_size = (ios->ol_state.nr_pages + pages_in_stripe) /
+		unsigned bio_size = (ios->nr_pages + pages_in_stripe) /
 				    ios->layout->group_width;
 
 		if (BIO_MAX_PAGES_KMALLOC < bio_size)
@@ -615,11 +635,11 @@ static int _add_stripe_unit(struct objio_state *ios,  unsigned *cur_pg,
 		unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
 		unsigned added_len;
 
-		BUG_ON(ios->ol_state.nr_pages <= pg);
+		BUG_ON(ios->nr_pages <= pg);
 		cur_len -= pglen;
 
 		added_len = bio_add_pc_page(q, per_dev->bio,
-					ios->ol_state.pages[pg], pglen, pgbase);
+					ios->pages[pg], pglen, pgbase);
 		if (unlikely(pglen != added_len))
 			return -ENOMEM;
 		pgbase = 0;
@@ -660,7 +680,7 @@ static int _prepare_one_group(struct objio_state *ios, u64 length,
 				cur_len = stripe_unit - si->unit_off;
 				page_off = si->unit_off & ~PAGE_MASK;
 				BUG_ON(page_off &&
-				      (page_off != ios->ol_state.pgbase));
+				      (page_off != ios->pgbase));
 			} else { /* dev > si->dev */
 				per_dev->offset = si->obj_offset - si->unit_off;
 				cur_len = stripe_unit;
@@ -693,8 +713,8 @@ out:
 
 static int _io_rw_pagelist(struct objio_state *ios, gfp_t gfp_flags)
 {
-	u64 length = ios->ol_state.count;
-	u64 offset = ios->ol_state.offset;
+	u64 length = ios->count;
+	u64 offset = ios->offset;
 	struct _striping_info si;
 	unsigned last_pg = 0;
 	int ret = 0;
@@ -748,7 +768,7 @@ static int _io_exec(struct objio_state *ios)
 	int ret = 0;
 	unsigned i;
 	objio_done_fn saved_done_fn = ios->done;
-	bool sync = ios->ol_state.sync;
+	bool sync = ios->sync;
 
 	if (sync) {
 		ios->done = _sync_done;
@@ -792,7 +812,7 @@ static int _read_done(struct objio_state *ios)
 	else
 		status = ret;
 
-	objlayout_read_done(&ios->ol_state, status, ios->ol_state.sync);
+	objlayout_read_done(&ios->ol_state, status, ios->sync);
 	return ret;
 }
 
@@ -854,12 +874,18 @@ err:
 	return ret;
 }
 
-int objio_read_pagelist(struct objlayout_io_state *ol_state)
+int objio_read_pagelist(struct nfs_read_data *rdata)
 {
-	struct objio_state *ios = container_of(ol_state, struct objio_state,
-					       ol_state);
+	struct objio_state *ios;
 	int ret;
 
+	ret = objio_alloc_io_state(NFS_I(rdata->inode)->layout,
+			rdata->lseg, rdata->args.pages, rdata->args.pgbase,
+			rdata->args.offset, rdata->args.count, rdata,
+			GFP_KERNEL, &ios);
+	if (unlikely(ret))
+		return ret;
+
 	ret = _io_rw_pagelist(ios, GFP_KERNEL);
 	if (unlikely(ret))
 		return ret;
@@ -886,7 +912,7 @@ static int _write_done(struct objio_state *ios)
 		status = ret;
 	}
 
-	objlayout_write_done(&ios->ol_state, status, ios->ol_state.sync);
+	objlayout_write_done(&ios->ol_state, status, ios->sync);
 	return ret;
 }
 
@@ -976,12 +1002,20 @@ err:
 	return ret;
 }
 
-int objio_write_pagelist(struct objlayout_io_state *ol_state, bool stable)
+int objio_write_pagelist(struct nfs_write_data *wdata, int how)
 {
-	struct objio_state *ios = container_of(ol_state, struct objio_state,
-					       ol_state);
+	struct objio_state *ios;
 	int ret;
 
+	ret = objio_alloc_io_state(NFS_I(wdata->inode)->layout,
+			wdata->lseg, wdata->args.pages, wdata->args.pgbase,
+			wdata->args.offset, wdata->args.count, wdata, GFP_NOFS,
+			&ios);
+	if (unlikely(ret))
+		return ret;
+
+	ios->sync = 0 != (how & FLUSH_SYNC);
+
 	/* TODO: ios->stable = stable; */
 	ret = _io_rw_pagelist(ios, GFP_NOFS);
 	if (unlikely(ret))
diff --git a/fs/nfs/objlayout/objlayout.c b/fs/nfs/objlayout/objlayout.c
index 99c807df11d..a82053ae559 100644
--- a/fs/nfs/objlayout/objlayout.c
+++ b/fs/nfs/objlayout/objlayout.c
@@ -156,59 +156,23 @@ last_byte_offset(u64 start, u64 len)
 	return end > start ? end - 1 : NFS4_MAX_UINT64;
 }
 
-static struct objlayout_io_state *
-objlayout_alloc_io_state(struct pnfs_layout_hdr *pnfs_layout_type,
-			struct page **pages,
-			unsigned pgbase,
-			loff_t offset,
-			size_t count,
-			struct pnfs_layout_segment *lseg,
-			void *rpcdata,
-			gfp_t gfp_flags)
+void _fix_verify_io_params(struct pnfs_layout_segment *lseg,
+			   struct page ***p_pages, unsigned *p_pgbase,
+			   u64 offset, unsigned long count)
 {
-	struct objlayout_io_state *state;
 	u64 lseg_end_offset;
 
-	dprintk("%s: allocating io_state\n", __func__);
-	if (objio_alloc_io_state(lseg, &state, gfp_flags))
-		return NULL;
-
 	BUG_ON(offset < lseg->pls_range.offset);
 	lseg_end_offset = end_offset(lseg->pls_range.offset,
 				     lseg->pls_range.length);
 	BUG_ON(offset >= lseg_end_offset);
-	if (offset + count > lseg_end_offset) {
-		count = lseg->pls_range.length -
-				(offset - lseg->pls_range.offset);
-		dprintk("%s: truncated count %Zd\n", __func__, count);
-	}
+	WARN_ON(offset + count > lseg_end_offset);
 
-	if (pgbase > PAGE_SIZE) {
-		pages += pgbase >> PAGE_SHIFT;
-		pgbase &= ~PAGE_MASK;
+	if (*p_pgbase > PAGE_SIZE) {
+		dprintk("%s: pgbase(0x%x) > PAGE_SIZE\n", __func__, *p_pgbase);
+		*p_pages += *p_pgbase >> PAGE_SHIFT;
+		*p_pgbase &= ~PAGE_MASK;
 	}
-
-	INIT_LIST_HEAD(&state->err_list);
-	state->lseg = lseg;
-	state->rpcdata = rpcdata;
-	state->pages = pages;
-	state->pgbase = pgbase;
-	state->nr_pages = (pgbase + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	state->offset = offset;
-	state->count = count;
-	state->sync = 0;
-
-	return state;
-}
-
-static void
-objlayout_free_io_state(struct objlayout_io_state *state)
-{
-	dprintk("%s: freeing io_state\n", __func__);
-	if (unlikely(!state))
-		return;
-
-	objio_free_io_state(state);
 }
 
 /*
@@ -217,12 +181,10 @@ objlayout_free_io_state(struct objlayout_io_state *state)
 static void
 objlayout_iodone(struct objlayout_io_state *state)
 {
-	dprintk("%s: state %p status\n", __func__, state);
-
 	if (likely(state->status >= 0)) {
-		objlayout_free_io_state(state);
+		objio_free_result(state);
 	} else {
-		struct objlayout *objlay = OBJLAYOUT(state->lseg->pls_layout);
+		struct objlayout *objlay = state->objlay;
 
 		spin_lock(&objlay->lock);
 		objlay->delta_space_valid = OBJ_DSU_INVALID;
@@ -289,15 +251,15 @@ objlayout_read_done(struct objlayout_io_state *state, ssize_t status, bool sync)
 {
 	struct nfs_read_data *rdata = state->rpcdata;
 
-	state->status = status;
-	dprintk("%s: Begin status=%zd eof=%d\n", __func__,
-		status, rdata->res.eof);
-	rdata->task.tk_status = status;
+	state->status = rdata->task.tk_status = status;
 	if (status >= 0)
 		rdata->res.count = status;
 	objlayout_iodone(state);
 	/* must not use state after this point */
 
+	dprintk("%s: Return status=%zd eof=%d sync=%d\n", __func__,
+		status, rdata->res.eof, sync);
+
 	if (sync)
 		pnfs_ld_read_done(rdata);
 	else {
@@ -314,7 +276,6 @@ objlayout_read_pagelist(struct nfs_read_data *rdata)
 {
 	loff_t offset = rdata->args.offset;
 	size_t count = rdata->args.count;
-	struct objlayout_io_state *state;
 	int err;
 	loff_t eof;
 
@@ -331,20 +292,14 @@ objlayout_read_pagelist(struct nfs_read_data *rdata)
 	}
 
 	rdata->res.eof = (offset + count) >= eof;
+	_fix_verify_io_params(rdata->lseg, &rdata->args.pages,
+			      &rdata->args.pgbase,
+			      rdata->args.offset, rdata->args.count);
 
-	state = objlayout_alloc_io_state(NFS_I(rdata->inode)->layout,
-					 rdata->args.pages, rdata->args.pgbase,
-					 offset, count,
-					 rdata->lseg, rdata,
-					 GFP_KERNEL);
-	if (unlikely(!state)) {
-		err = -ENOMEM;
-		goto out;
-	}
 	dprintk("%s: inode(%lx) offset 0x%llx count 0x%Zx eof=%d\n",
 		__func__, rdata->inode->i_ino, offset, count, rdata->res.eof);
 
-	err = objio_read_pagelist(state);
+	err = objio_read_pagelist(rdata);
  out:
 	if (unlikely(err)) {
 		rdata->pnfs_error = err;
@@ -374,23 +329,18 @@ void
 objlayout_write_done(struct objlayout_io_state *state, ssize_t status,
 		     bool sync)
 {
-	struct nfs_write_data *wdata;
+	struct nfs_write_data *wdata = state->rpcdata;
 
-	dprintk("%s: Begin\n", __func__);
-	wdata = state->rpcdata;
-	state->status = status;
-	wdata->task.tk_status = status;
+	state->status = wdata->task.tk_status = status;
 	if (status >= 0) {
 		wdata->res.count = status;
 		wdata->verf.committed = state->committed;
-		dprintk("%s: Return status %d committed %d\n",
-			__func__, wdata->task.tk_status,
-			wdata->verf.committed);
-	} else
-		dprintk("%s: Return status %d\n",
-			__func__, wdata->task.tk_status);
+	}
 	objlayout_iodone(state);
-	/* must not use state after this point */
+	/* must not use oir after this point */
+
+	dprintk("%s: Return status %zd committed %d sync=%d\n", __func__,
+		status, wdata->verf.committed, sync);
 
 	if (sync)
 		pnfs_ld_write_done(wdata);
@@ -407,25 +357,13 @@ enum pnfs_try_status
 objlayout_write_pagelist(struct nfs_write_data *wdata,
 			 int how)
 {
-	struct objlayout_io_state *state;
 	int err;
 
-	state = objlayout_alloc_io_state(NFS_I(wdata->inode)->layout,
-					 wdata->args.pages,
-					 wdata->args.pgbase,
-					 wdata->args.offset,
-					 wdata->args.count,
-					 wdata->lseg, wdata,
-					 GFP_NOFS);
-	if (unlikely(!state)) {
-		err = -ENOMEM;
-		goto out;
-	}
+	_fix_verify_io_params(wdata->lseg, &wdata->args.pages,
+			      &wdata->args.pgbase,
+			      wdata->args.offset, wdata->args.count);
 
-	state->sync = how & FLUSH_SYNC;
-
-	err = objio_write_pagelist(state, how & FLUSH_STABLE);
- out:
+	err = objio_write_pagelist(wdata, how);
 	if (unlikely(err)) {
 		wdata->pnfs_error = err;
 		dprintk("%s: Returned Error %d\n", __func__, err);
@@ -564,7 +502,7 @@ encode_accumulated_error(struct objlayout *objlay, __be32 *p)
 			merge_ioerr(&accumulated_err, ioerr);
 		}
 		list_del(&state->err_list);
-		objlayout_free_io_state(state);
+		objio_free_result(state);
 	}
 
 	pnfs_osd_xdr_encode_ioerr(p, &accumulated_err);
@@ -632,7 +570,7 @@ objlayout_encode_layoutreturn(struct pnfs_layout_hdr *pnfslay,
 			goto loop_done;
 		}
 		list_del(&state->err_list);
-		objlayout_free_io_state(state);
+		objio_free_result(state);
 	}
 loop_done:
 	spin_unlock(&objlay->lock);
diff --git a/fs/nfs/objlayout/objlayout.h b/fs/nfs/objlayout/objlayout.h
index 4edac9b6ac0..d7b2ccfa213 100644
--- a/fs/nfs/objlayout/objlayout.h
+++ b/fs/nfs/objlayout/objlayout.h
@@ -75,14 +75,7 @@ OBJLAYOUT(struct pnfs_layout_hdr *lo)
  * embedded in objects provider io_state data structure
  */
 struct objlayout_io_state {
-	struct pnfs_layout_segment *lseg;
-
-	struct page **pages;
-	unsigned pgbase;
-	unsigned nr_pages;
-	unsigned long count;
-	loff_t offset;
-	bool sync;
+	struct objlayout *objlay;
 
 	void *rpcdata;
 	int status;             /* res */
@@ -99,6 +92,18 @@ struct objlayout_io_state {
 	struct pnfs_osd_ioerr *ioerrs;
 };
 
+static inline
+void objlayout_init_ioerrs(struct objlayout_io_state *oir, unsigned num_comps,
+			struct pnfs_osd_ioerr *ioerrs, void *rpcdata,
+			struct pnfs_layout_hdr *pnfs_layout_type)
+{
+	oir->objlay = OBJLAYOUT(pnfs_layout_type);
+	oir->rpcdata = rpcdata;
+	INIT_LIST_HEAD(&oir->err_list);
+	oir->num_comps = num_comps;
+	oir->ioerrs = ioerrs;
+}
+
 /*
  * Raid engine I/O API
  */
@@ -109,15 +114,10 @@ extern int objio_alloc_lseg(struct pnfs_layout_segment **outp,
 	gfp_t gfp_flags);
 extern void objio_free_lseg(struct pnfs_layout_segment *lseg);
 
-extern int objio_alloc_io_state(
-	struct pnfs_layout_segment *lseg,
-	struct objlayout_io_state **outp,
-	gfp_t gfp_flags);
-extern void objio_free_io_state(struct objlayout_io_state *state);
+extern void objio_free_result(struct objlayout_io_state *state);
 
-extern int objio_read_pagelist(struct objlayout_io_state *ol_state);
-extern int objio_write_pagelist(struct objlayout_io_state *ol_state,
-				    bool stable);
+extern int objio_read_pagelist(struct nfs_read_data *rdata);
+extern int objio_write_pagelist(struct nfs_write_data *wdata, int how);
 
 /*
  * callback API
@@ -127,10 +127,8 @@ extern void objlayout_io_set_result(struct objlayout_io_state *state,
 			int osd_error, u64 offset, u64 length, bool is_write);
 
 static inline void
-objlayout_add_delta_space_used(struct objlayout_io_state *state, s64 space_used)
+objlayout_add_delta_space_used(struct objlayout *objlay, s64 space_used)
 {
-	struct objlayout *objlay = OBJLAYOUT(state->lseg->pls_layout);
-
 	/* If one of the I/Os errored out and the delta_space_used was
 	 * invalid we render the complete report as invalid. Protocol mandate
 	 * the DSU be accurate or not reported.