pnfs-obj: Return PNFS_NOT_ATTEMPTED in case of read/write_pagelist

objlayout driver was always returning PNFS_ATTEMPTED from it's
read/write_pagelist operations. Even on error. Fix that.

Start by establishing an error return API from io-engine, by
not returning ssize_t (length-or-error) but returning "int"
0=OK, 0>Error. And clean up all return types in io-engine.

Then if io-engine returned error return PNFS_NOT_ATTEMPTED
to generic layer. (With a dprint)
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/objlayout/objio_osd.c

@@ -142,7 +142,7 @@ OBJIO_LSEG(struct pnfs_layout_segment *lseg)
 }
 
 struct objio_state;
-typedef ssize_t (*objio_done_fn)(struct objio_state *ios);
+typedef int (*objio_done_fn)(struct objio_state *ios);
 
 struct objio_state {
 	/* Generic layer */
@@ -720,7 +720,7 @@ static int _io_rw_pagelist(struct objio_state *ios, gfp_t gfp_flags)
 	return 0;
 }
 
-static ssize_t _sync_done(struct objio_state *ios)
+static int _sync_done(struct objio_state *ios)
 {
 	struct completion *waiting = ios->private;
 
@@ -742,10 +742,10 @@ static void _done_io(struct osd_request *or, void *p)
 	kref_put(&ios->kref, _last_io);
 }
 
-static ssize_t _io_exec(struct objio_state *ios)
+static int _io_exec(struct objio_state *ios)
 {
 	DECLARE_COMPLETION_ONSTACK(wait);
-	ssize_t status = 0; /* sync status */
+	int ret = 0;
 	unsigned i;
 	objio_done_fn saved_done_fn = ios->done;
 	bool sync = ios->ol_state.sync;
@@ -771,16 +771,16 @@ static ssize_t _io_exec(struct objio_state *ios)
 
 	if (sync) {
 		wait_for_completion(&wait);
-		status = saved_done_fn(ios);
+		ret = saved_done_fn(ios);
 	}
 
-	return status;
+	return ret;
 }
 
 /*
  * read
  */
-static ssize_t _read_done(struct objio_state *ios)
+static int _read_done(struct objio_state *ios)
 {
 	ssize_t status;
 	int ret = _io_check(ios, false);
@@ -793,7 +793,7 @@ static ssize_t _read_done(struct objio_state *ios)
 		status = ret;
 
 	objlayout_read_done(&ios->ol_state, status, ios->ol_state.sync);
-	return status;
+	return ret;
 }
 
 static int _read_mirrors(struct objio_state *ios, unsigned cur_comp)
@@ -833,7 +833,7 @@ static int _read_mirrors(struct objio_state *ios, unsigned cur_comp)
 	return ret;
 }
 
-static ssize_t _read_exec(struct objio_state *ios)
+static int _read_exec(struct objio_state *ios)
 {
 	unsigned i;
 	int ret;
@@ -847,14 +847,14 @@ static ssize_t _read_exec(struct objio_state *ios)
 	}
 
 	ios->done = _read_done;
-	return _io_exec(ios); /* In sync mode exec returns the io status */
+	return _io_exec(ios);
 
 err:
 	_io_free(ios);
 	return ret;
 }
 
-ssize_t objio_read_pagelist(struct objlayout_io_state *ol_state)
+int objio_read_pagelist(struct objlayout_io_state *ol_state)
 {
 	struct objio_state *ios = container_of(ol_state, struct objio_state,
 					       ol_state);
@@ -870,7 +870,7 @@ ssize_t objio_read_pagelist(struct objlayout_io_state *ol_state)
 /*
  * write
  */
-static ssize_t _write_done(struct objio_state *ios)
+static int _write_done(struct objio_state *ios)
 {
 	ssize_t status;
 	int ret = _io_check(ios, true);
@@ -887,7 +887,7 @@ static ssize_t _write_done(struct objio_state *ios)
 	}
 
 	objlayout_write_done(&ios->ol_state, status, ios->ol_state.sync);
-	return status;
+	return ret;
 }
 
 static int _write_mirrors(struct objio_state *ios, unsigned cur_comp)
@@ -955,7 +955,7 @@ static int _write_mirrors(struct objio_state *ios, unsigned cur_comp)
 	return ret;
 }
 
-static ssize_t _write_exec(struct objio_state *ios)
+static int _write_exec(struct objio_state *ios)
 {
 	unsigned i;
 	int ret;
@@ -969,14 +969,14 @@ static ssize_t _write_exec(struct objio_state *ios)
 	}
 
 	ios->done = _write_done;
-	return _io_exec(ios); /* In sync mode exec returns the io->status */
+	return _io_exec(ios);
 
 err:
 	_io_free(ios);
 	return ret;
 }
 
-ssize_t objio_write_pagelist(struct objlayout_io_state *ol_state, bool stable)
+int objio_write_pagelist(struct objlayout_io_state *ol_state, bool stable)
 {
 	struct objio_state *ios = container_of(ol_state, struct objio_state,
 					       ol_state);

fs/nfs/objlayout/objlayout.c

@@ -315,16 +315,13 @@ 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;
-	ssize_t status = 0;
+	int err;
 	loff_t eof;
 
-	dprintk("%s: Begin inode %p offset %llu count %d\n",
-		__func__, rdata->inode, offset, (int)count);
-
 	eof = i_size_read(rdata->inode);
 	if (unlikely(offset + count > eof)) {
 		if (offset >= eof) {
-			status = 0;
+			err = 0;
 			rdata->res.count = 0;
 			rdata->res.eof = 1;
 			/*FIXME: do we need to call pnfs_ld_read_done() */
@@ -341,14 +338,19 @@ objlayout_read_pagelist(struct nfs_read_data *rdata)
 					 rdata->lseg, rdata,
 					 GFP_KERNEL);
 	if (unlikely(!state)) {
-		status = -ENOMEM;
+		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);
 
-	status = objio_read_pagelist(state);
+	err = objio_read_pagelist(state);
  out:
-	dprintk("%s: Return status %Zd\n", __func__, status);
-	rdata->pnfs_error = status;
+	if (unlikely(err)) {
+		rdata->pnfs_error = err;
+		dprintk("%s: Returned Error %d\n", __func__, err);
+		return PNFS_NOT_ATTEMPTED;
+	}
 	return PNFS_ATTEMPTED;
 }
 
@@ -406,10 +408,7 @@ objlayout_write_pagelist(struct nfs_write_data *wdata,
 			 int how)
 {
 	struct objlayout_io_state *state;
-	ssize_t status;
-
-	dprintk("%s: Begin inode %p offset %llu count %u\n",
-		__func__, wdata->inode, wdata->args.offset, wdata->args.count);
+	int err;
 
 	state = objlayout_alloc_io_state(NFS_I(wdata->inode)->layout,
 					 wdata->args.pages,
@@ -419,16 +418,19 @@ objlayout_write_pagelist(struct nfs_write_data *wdata,
 					 wdata->lseg, wdata,
 					 GFP_NOFS);
 	if (unlikely(!state)) {
-		status = -ENOMEM;
+		err = -ENOMEM;
 		goto out;
 	}
 
 	state->sync = how & FLUSH_SYNC;
 
-	status = objio_write_pagelist(state, how & FLUSH_STABLE);
+	err = objio_write_pagelist(state, how & FLUSH_STABLE);
  out:
-	dprintk("%s: Return status %Zd\n", __func__, status);
-	wdata->pnfs_error = status;
+	if (unlikely(err)) {
+		wdata->pnfs_error = err;
+		dprintk("%s: Returned Error %d\n", __func__, err);
+		return PNFS_NOT_ATTEMPTED;
+	}
 	return PNFS_ATTEMPTED;
 }
 

fs/nfs/objlayout/objlayout.h

@@ -115,8 +115,8 @@ extern int objio_alloc_io_state(
 	gfp_t gfp_flags);
 extern void objio_free_io_state(struct objlayout_io_state *state);
 
-extern ssize_t objio_read_pagelist(struct objlayout_io_state *ol_state);
-extern ssize_t objio_write_pagelist(struct objlayout_io_state *ol_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);
 
 /*