NFS: create common nfs_pgio_header for both read and write

In order to avoid duplicating all the data in nfs_read_data whenever we
split it up into multiple RPC calls (either due to a short read result
or due to rsize < PAGE_SIZE), we split out the bits that are the same
per RPC call into a separate "header" structure.

The goal this patch moves towards is to have a single header
refcounted by several rpc_data structures.  Thus, want to always refer
from rpc_data to the header, and not the other way.  This patch comes
close to that ideal, but the directio code currently needs some
special casing, isolated in the nfs_direct_[read_write]hdr_release()
functions.  This will be dealt with in a future patch.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 43 insertions, 36 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 7f6a23f0244e..7a482517f4c6 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -187,7 +187,6 @@ static void bl_end_io_read(struct bio *bio, int err)
         struct parallel_io *par = bio->bi_private;
         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-        struct nfs_read_data *rdata = (struct nfs_read_data *)par->data;
 
         do {
                 struct page *page = bvec->bv_page;
@@ -198,9 +197,12 @@ static void bl_end_io_read(struct bio *bio, int err)
                         SetPageUptodate(page);
         } while (bvec >= bio->bi_io_vec);
         if (!uptodate) {
-                if (!rdata->pnfs_error)
-                        rdata->pnfs_error = -EIO;
-                pnfs_set_lo_fail(rdata->lseg);
+                struct nfs_read_data *rdata = par->data;
+                struct nfs_pgio_header *header = rdata->header;
+
+                if (!header->pnfs_error)
+                        header->pnfs_error = -EIO;
+                pnfs_set_lo_fail(header->lseg);
         }
         bio_put(bio);
         put_parallel(par);
@@ -221,7 +223,7 @@ bl_end_par_io_read(void *data, int unused)
 {
         struct nfs_read_data *rdata = data;
 
-        rdata->task.tk_status = rdata->pnfs_error;
+        rdata->task.tk_status = rdata->header->pnfs_error;
         INIT_WORK(&rdata->task.u.tk_work, bl_read_cleanup);
         schedule_work(&rdata->task.u.tk_work);
 }
@@ -229,6 +231,7 @@ bl_end_par_io_read(void *data, int unused)
 static enum pnfs_try_status
 bl_read_pagelist(struct nfs_read_data *rdata)
 {
+        struct nfs_pgio_header *header = rdata->header;
         int i, hole;
         struct bio *bio = NULL;
         struct pnfs_block_extent *be = NULL, *cow_read = NULL;
@@ -256,10 +259,10 @@ bl_read_pagelist(struct nfs_read_data *rdata)
                         bl_put_extent(cow_read);
                         bio = bl_submit_bio(READ, bio);
                         /* Get the next one */
-                        be = bl_find_get_extent(BLK_LSEG2EXT(rdata->lseg),
+                        be = bl_find_get_extent(BLK_LSEG2EXT(header->lseg),
                                              isect, &cow_read);
                         if (!be) {
-                                rdata->pnfs_error = -EIO;
+                                header->pnfs_error = -EIO;
                                 goto out;
                         }
                         extent_length = be->be_length -
@@ -286,7 +289,7 @@ bl_read_pagelist(struct nfs_read_data *rdata)
                                                  isect, pages[i], be_read,
                                                  bl_end_io_read, par);
                         if (IS_ERR(bio)) {
-                                rdata->pnfs_error = PTR_ERR(bio);
+                                header->pnfs_error = PTR_ERR(bio);
                                 bio = NULL;
                                 goto out;
                         }
@@ -294,9 +297,9 @@ bl_read_pagelist(struct nfs_read_data *rdata)
                 isect += PAGE_CACHE_SECTORS;
                 extent_length -= PAGE_CACHE_SECTORS;
         }
-        if ((isect << SECTOR_SHIFT) >= rdata->inode->i_size) {
+        if ((isect << SECTOR_SHIFT) >= header->inode->i_size) {
                 rdata->res.eof = 1;
-                rdata->res.count = rdata->inode->i_size - f_offset;
+                rdata->res.count = header->inode->i_size - f_offset;
         } else {
                 rdata->res.count = (isect << SECTOR_SHIFT) - f_offset;
         }
@@ -345,7 +348,6 @@ static void bl_end_io_write_zero(struct bio *bio, int err)
         struct parallel_io *par = bio->bi_private;
         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-        struct nfs_write_data *wdata = (struct nfs_write_data *)par->data;
 
         do {
                 struct page *page = bvec->bv_page;
@@ -358,9 +360,12 @@ static void bl_end_io_write_zero(struct bio *bio, int err)
         } while (bvec >= bio->bi_io_vec);
 
         if (unlikely(!uptodate)) {
-                if (!wdata->pnfs_error)
-                        wdata->pnfs_error = -EIO;
-                pnfs_set_lo_fail(wdata->lseg);
+                struct nfs_write_data *data = par->data;
+                struct nfs_pgio_header *header = data->header;
+
+                if (!header->pnfs_error)
+                        header->pnfs_error = -EIO;
+                pnfs_set_lo_fail(header->lseg);
         }
         bio_put(bio);
         put_parallel(par);
@@ -370,12 +375,13 @@ static void bl_end_io_write(struct bio *bio, int err)
 {
         struct parallel_io *par = bio->bi_private;
         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
-        struct nfs_write_data *wdata = (struct nfs_write_data *)par->data;
+        struct nfs_write_data *data = par->data;
+        struct nfs_pgio_header *header = data->header;
 
         if (!uptodate) {
-                if (!wdata->pnfs_error)
-                        wdata->pnfs_error = -EIO;
-                pnfs_set_lo_fail(wdata->lseg);
+                if (!header->pnfs_error)
+                        header->pnfs_error = -EIO;
+                pnfs_set_lo_fail(header->lseg);
         }
         bio_put(bio);
         put_parallel(par);
@@ -391,9 +397,9 @@ static void bl_write_cleanup(struct work_struct *work)
         dprintk("%s enter\n", __func__);
         task = container_of(work, struct rpc_task, u.tk_work);
         wdata = container_of(task, struct nfs_write_data, task);
-        if (likely(!wdata->pnfs_error)) {
+        if (likely(!wdata->header->pnfs_error)) {
                 /* Marks for LAYOUTCOMMIT */
-                mark_extents_written(BLK_LSEG2EXT(wdata->lseg),
+                mark_extents_written(BLK_LSEG2EXT(wdata->header->lseg),
                                      wdata->args.offset, wdata->args.count);
         }
         pnfs_ld_write_done(wdata);
@@ -404,12 +410,12 @@ static void bl_end_par_io_write(void *data, int num_se)
 {
         struct nfs_write_data *wdata = data;
 
-        if (unlikely(wdata->pnfs_error)) {
-                bl_free_short_extents(&BLK_LSEG2EXT(wdata->lseg)->bl_inval,
+        if (unlikely(wdata->header->pnfs_error)) {
+                bl_free_short_extents(&BLK_LSEG2EXT(wdata->header->lseg)->bl_inval,
                                         num_se);
         }
 
-        wdata->task.tk_status = wdata->pnfs_error;
+        wdata->task.tk_status = wdata->header->pnfs_error;
         wdata->verf.committed = NFS_FILE_SYNC;
         INIT_WORK(&wdata->task.u.tk_work, bl_write_cleanup);
         schedule_work(&wdata->task.u.tk_work);
@@ -540,6 +546,7 @@ check_page:
 static enum pnfs_try_status
 bl_write_pagelist(struct nfs_write_data *wdata, int sync)
 {
+        struct nfs_pgio_header *header = wdata->header;
         int i, ret, npg_zero, pg_index, last = 0;
         struct bio *bio = NULL;
         struct pnfs_block_extent *be = NULL, *cow_read = NULL;
@@ -552,7 +559,7 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync)
         pgoff_t index;
         u64 temp;
         int npg_per_block =
-            NFS_SERVER(wdata->inode)->pnfs_blksize >> PAGE_CACHE_SHIFT;
+            NFS_SERVER(header->inode)->pnfs_blksize >> PAGE_CACHE_SHIFT;
 
         dprintk("%s enter, %Zu@%lld\n", __func__, count, offset);
         /* At this point, wdata->pages is a (sequential) list of nfs_pages.
@@ -566,7 +573,7 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync)
         /* At this point, have to be more careful with error handling */
 
         isect = (sector_t) ((offset & (long)PAGE_CACHE_MASK) >> SECTOR_SHIFT);
-        be = bl_find_get_extent(BLK_LSEG2EXT(wdata->lseg), isect, &cow_read);
+        be = bl_find_get_extent(BLK_LSEG2EXT(header->lseg), isect, &cow_read);
         if (!be || !is_writable(be, isect)) {
                 dprintk("%s no matching extents!\n", __func__);
                 goto out_mds;
@@ -597,10 +604,10 @@ fill_invalid_ext:
                         dprintk("%s zero %dth page: index %lu isect %llu\n",
                                 __func__, npg_zero, index,
                                 (unsigned long long)isect);
-                        page = bl_find_get_zeroing_page(wdata->inode, index,
+                        page = bl_find_get_zeroing_page(header->inode, index,
                                                         cow_read);
                         if (unlikely(IS_ERR(page))) {
-                                wdata->pnfs_error = PTR_ERR(page);
+                                header->pnfs_error = PTR_ERR(page);
                                 goto out;
                         } else if (page == NULL)
                                 goto next_page;
@@ -612,7 +619,7 @@ fill_invalid_ext:
                                         __func__, ret);
                                 end_page_writeback(page);
                                 page_cache_release(page);
-                                wdata->pnfs_error = ret;
+                                header->pnfs_error = ret;
                                 goto out;
                         }
                         if (likely(!bl_push_one_short_extent(be->be_inval)))
@@ -620,11 +627,11 @@ fill_invalid_ext:
                         else {
                                 end_page_writeback(page);
                                 page_cache_release(page);
-                                wdata->pnfs_error = -ENOMEM;
+                                header->pnfs_error = -ENOMEM;
                                 goto out;
                         }
                         /* FIXME: This should be done in bi_end_io */
-                        mark_extents_written(BLK_LSEG2EXT(wdata->lseg),
+                        mark_extents_written(BLK_LSEG2EXT(header->lseg),
                                              page->index << PAGE_CACHE_SHIFT,
                                              PAGE_CACHE_SIZE);
 
@@ -632,7 +639,7 @@ fill_invalid_ext:
                                                  isect, page, be,
                                                  bl_end_io_write_zero, par);
                         if (IS_ERR(bio)) {
-                                wdata->pnfs_error = PTR_ERR(bio);
+                                header->pnfs_error = PTR_ERR(bio);
                                 bio = NULL;
                                 goto out;
                         }
@@ -653,10 +660,10 @@ next_page:
                         bl_put_extent(be);
                         bio = bl_submit_bio(WRITE, bio);
                         /* Get the next one */
-                        be = bl_find_get_extent(BLK_LSEG2EXT(wdata->lseg),
+                        be = bl_find_get_extent(BLK_LSEG2EXT(header->lseg),
                                              isect, NULL);
                         if (!be || !is_writable(be, isect)) {
-                                wdata->pnfs_error = -EINVAL;
+                                header->pnfs_error = -EINVAL;
                                 goto out;
                         }
                         if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
@@ -664,7 +671,7 @@ next_page:
                                                                 be->be_inval)))
                                         par->bse_count++;
                                 else {
-                                        wdata->pnfs_error = -ENOMEM;
+                                        header->pnfs_error = -ENOMEM;
                                         goto out;
                                 }
                         }
@@ -677,7 +684,7 @@ next_page:
                         if (unlikely(ret)) {
                                 dprintk("%s bl_mark_sectors_init fail %d\n",
                                         __func__, ret);
-                                wdata->pnfs_error = ret;
+                                header->pnfs_error = ret;
                                 goto out;
                         }
                 }
@@ -685,7 +692,7 @@ next_page:
                                          isect, pages[i], be,
                                          bl_end_io_write, par);
                 if (IS_ERR(bio)) {
-                        wdata->pnfs_error = PTR_ERR(bio);
+                        header->pnfs_error = PTR_ERR(bio);
                         bio = NULL;
                         goto out;
                 }