[PATCH 8/8] pnfsblock: alloc short extent before submit bio

[Peng Tao <bergwolf@gmail.com>]

As discussed earlier, it is better for block client to allocate memoroy for
tracking extents state before submitting bio. So the patch does it by allocating
a short_extent for every INVALID extent touched by write pagelist and for
every zeroing page we created, saving them in layout header.
Then in end_io we can just use them to create commit list items and avoid
memory allocation there.

Signed-off-by: Peng Tao <peng_tao@emc.com>
---
 fs/nfs/blocklayout/blocklayout.c |   70 +++++++++++++++++++++++++++++---------
 fs/nfs/blocklayout/blocklayout.h |    3 +-
 fs/nfs/blocklayout/extents.c     |   13 ++-----
 3 files changed, 60 insertions(+), 26 deletions(-)

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index cb4ff0f..53cd332 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -90,8 +90,9 @@ static int is_writable(struct pnfs_block_extent *be, sector_t isect)
  */
 struct parallel_io {
 	struct kref refcnt;
-	void (*pnfs_callback) (void *data);
+	void (*pnfs_callback) (void *data, int num_se);
 	void *data;
+	int bse_count;
 };
 
 static inline struct parallel_io *alloc_parallel(void *data)
@@ -102,6 +103,7 @@ static inline struct parallel_io *alloc_parallel(void *data)
 	if (rv) {
 		rv->data = data;
 		kref_init(&rv->refcnt);
+		rv->bse_count = 0;
 	}
 	return rv;
 }
@@ -116,7 +118,7 @@ static void destroy_parallel(struct kref *kref)
 	struct parallel_io *p = container_of(kref, struct parallel_io, refcnt);
 
 	dprintk("%s enter\n", __func__);
-	p->pnfs_callback(p->data);
+	p->pnfs_callback(p->data, p->bse_count);
 	kfree(p);
 }
 
@@ -211,7 +213,7 @@ static void bl_read_cleanup(struct work_struct *work)
 }
 
 static void
-bl_end_par_io_read(void *data)
+bl_end_par_io_read(void *data, int unused)
 {
 	struct nfs_read_data *rdata = data;
 
@@ -312,6 +314,7 @@ static void mark_extents_written(struct pnfs_block_layout *bl,
 {
 	sector_t isect, end;
 	struct pnfs_block_extent *be;
+	struct pnfs_block_short_extent *se;
 
 	dprintk("%s(%llu, %u)\n", __func__, offset, count);
 	if (count == 0)
@@ -324,8 +327,11 @@ static void mark_extents_written(struct pnfs_block_layout *bl,
 		be = bl_find_get_extent(bl, isect, NULL);
 		BUG_ON(!be); /* FIXME */
 		len = min(end, be->be_f_offset + be->be_length) - isect;
-		if (be->be_state == PNFS_BLOCK_INVALID_DATA)
-			bl_mark_for_commit(be, isect, len); /* What if fails? */
+		if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
+			se = bl_pop_short_extent(be->be_inval, 1);
+			BUG_ON(!se);
+			bl_mark_for_commit(be, isect, len, se);
+		}
 		isect += len;
 		bl_put_extent(be);
 	}
@@ -347,7 +353,8 @@ static void bl_end_io_write_zero(struct bio *bio, int err)
 		end_page_writeback(page);
 		page_cache_release(page);
 	} while (bvec >= bio->bi_io_vec);
-	if (!uptodate) {
+
+	if (unlikely(!uptodate)) {
 		if (!wdata->pnfs_error)
 			wdata->pnfs_error = -EIO;
 		pnfs_set_lo_fail(wdata->lseg);
@@ -356,7 +363,6 @@ static void bl_end_io_write_zero(struct bio *bio, int err)
 	put_parallel(par);
 }
 
-/* This is basically copied from mpage_end_io_read */
 static void bl_end_io_write(struct bio *bio, int err)
 {
 	struct parallel_io *par = bio->bi_private;
@@ -382,7 +388,7 @@ 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 (!wdata->pnfs_error) {
+	if (likely(!wdata->pnfs_error)) {
 		/* Marks for LAYOUTCOMMIT */
 		mark_extents_written(BLK_LSEG2EXT(wdata->lseg),
 				     wdata->args.offset, wdata->args.count);
@@ -391,9 +397,16 @@ static void bl_write_cleanup(struct work_struct *work)
 }
 
 /* Called when last of bios associated with a bl_write_pagelist call finishes */
-static void bl_end_par_io_write(void *data)
+static void bl_end_par_io_write(void *data, int num_se)
 {
 	struct nfs_write_data *wdata = data;
+	struct pnfs_block_short_extent *se;
+
+	if (unlikely(wdata->pnfs_error)) {
+		se = bl_pop_short_extent(&BLK_LSEG2EXT(wdata->lseg)->bl_inval,
+					num_se);
+		kfree(se);
+	}
 
 	wdata->task.tk_status = wdata->pnfs_error;
 	wdata->verf.committed = NFS_FILE_SYNC;
@@ -548,7 +561,7 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync)
 	 */
 	par = alloc_parallel(wdata);
 	if (!par)
-		return PNFS_NOT_ATTEMPTED;
+		goto out_mds;
 	par->pnfs_callback = bl_end_par_io_write;
 	/* At this point, have to be more careful with error handling */
 
@@ -556,12 +569,15 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync)
 	be = bl_find_get_extent(BLK_LSEG2EXT(wdata->lseg), isect, &cow_read);
 	if (!be || !is_writable(be, isect)) {
 		dprintk("%s no matching extents!\n", __func__);
-		wdata->pnfs_error = -EINVAL;
-		goto out;
+		goto out_mds;
 	}
 
 	/* First page inside INVALID extent */
 	if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
+		if (likely(!bl_push_one_short_extent(be->be_inval)))
+			par->bse_count++;
+		else
+			goto out_mds;
 		temp = offset >> PAGE_CACHE_SHIFT;
 		npg_zero = do_div(temp, npg_per_block);
 		isect = (sector_t) (((offset - npg_zero * PAGE_CACHE_SIZE) &
@@ -598,6 +614,19 @@ fill_invalid_ext:
 				wdata->pnfs_error = ret;
 				goto out;
 			}
+			if (likely(!bl_push_one_short_extent(be->be_inval)))
+				par->bse_count++;
+			else {
+				end_page_writeback(page);
+				page_cache_release(page);
+				wdata->pnfs_error = -ENOMEM;
+				goto out;
+			}
+			/* FIXME: This should be done in bi_end_io */
+			mark_extents_written(BLK_LSEG2EXT(wdata->lseg),
+					     page->index << PAGE_CACHE_SHIFT,
+					     PAGE_CACHE_SIZE);
+
 			bio = bl_add_page_to_bio(bio, npg_zero, WRITE,
 						 isect, page, be,
 						 bl_end_io_write_zero, par);
@@ -606,10 +635,6 @@ fill_invalid_ext:
 				bio = NULL;
 				goto out;
 			}
-			/* FIXME: This should be done in bi_end_io */
-			mark_extents_written(BLK_LSEG2EXT(wdata->lseg),
-					     page->index << PAGE_CACHE_SHIFT,
-					     PAGE_CACHE_SIZE);
 next_page:
 			isect += PAGE_CACHE_SECTORS;
 			extent_length -= PAGE_CACHE_SECTORS;
@@ -633,6 +658,14 @@ next_page:
 				wdata->pnfs_error = -EINVAL;
 				goto out;
 			}
+			if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
+			    if (likely(!bl_push_one_short_extent(be->be_inval)))
+				par->bse_count++;
+			    else {
+				wdata->pnfs_error = -ENOMEM;
+				goto out;
+			    }
+			}
 			extent_length = be->be_length -
 			    (isect - be->be_f_offset);
 		}
@@ -680,6 +713,11 @@ out:
 	bl_submit_bio(WRITE, bio);
 	put_parallel(par);
 	return PNFS_ATTEMPTED;
+out_mds:
+	bl_put_extent(be);
+	if (par)
+		kfree(par);
+	return PNFS_NOT_ATTEMPTED;
 }
 
 /* FIXME - range ignored */
diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h
index df0e0fb..4986c23 100644
--- a/fs/nfs/blocklayout/blocklayout.h
+++ b/fs/nfs/blocklayout/blocklayout.h
@@ -201,7 +201,8 @@ void clean_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
 int bl_add_merge_extent(struct pnfs_block_layout *bl,
 			 struct pnfs_block_extent *new);
 int bl_mark_for_commit(struct pnfs_block_extent *be,
-			sector_t offset, sector_t length);
+			sector_t offset, sector_t length,
+			struct pnfs_block_short_extent *new);
 int bl_push_one_short_extent(struct pnfs_inval_markings *marks);
 struct pnfs_block_short_extent*
 bl_pop_short_extent(struct pnfs_inval_markings *marks, int num_to_pop);
diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c
index 72c7fa1..21da3a3 100644
--- a/fs/nfs/blocklayout/extents.c
+++ b/fs/nfs/blocklayout/extents.c
@@ -370,20 +370,18 @@ static void add_to_commitlist(struct pnfs_block_layout *bl,
 
 /* Note the range described by offset, length is guaranteed to be contained
  * within be.
+ * new will be freed, either by this function or add_to_commitlist if they
+ * decide not to use it, or after LAYOUTCOMMIT uses it in the commitlist.
  */
 int bl_mark_for_commit(struct pnfs_block_extent *be,
-		    sector_t offset, sector_t length)
+		    sector_t offset, sector_t length,
+		    struct pnfs_block_short_extent *new)
 {
 	sector_t new_end, end = offset + length;
-	struct pnfs_block_short_extent *new;
 	struct pnfs_block_layout *bl = container_of(be->be_inval,
 						    struct pnfs_block_layout,
 						    bl_inval);
 
-	new = kmalloc(sizeof(*new), GFP_NOFS);
-	if (!new)
-		return -ENOMEM;
-
 	mark_written_sectors(be->be_inval, offset, length);
 	/* We want to add the range to commit list, but it must be
 	 * block-normalized, and verified that the normalized range has
@@ -413,9 +411,6 @@ int bl_mark_for_commit(struct pnfs_block_extent *be,
 	new->bse_mdev = be->be_mdev;
 
 	spin_lock(&bl->bl_ext_lock);
-	/* new will be freed, either by add_to_commitlist if it decides not
-	 * to use it, or after LAYOUTCOMMIT uses it in the commitlist.
-	 */
 	add_to_commitlist(bl, new);
 	spin_unlock(&bl->bl_ext_lock);
 	return 0;
-- 
1.7.1.262.g5ef3d