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 0c7c9ec24e67..48eb91aad554 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 99c807df11dc..a82053ae5595 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 4edac9b6ac0c..d7b2ccfa2132 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.