pnfsblock: alloc short extent before submit bio

As discussed earlier, it is better for block client to allocate memory 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>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 131 insertions, 37 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 9215c6644a3a..48cfac31f64c 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);
 }
 
@@ -216,7 +218,7 @@ 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;
 
@@ -317,6 +319,7 @@ 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)
@@ -329,8 +332,11 @@ 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_one_short_extent(be->be_inval);
+			BUG_ON(!se);
+			bl_mark_for_commit(be, isect, len, se);
+		}
 		isect += len;
 		bl_put_extent(be);
 	}
@@ -352,7 +358,8 @@ 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);
@@ -361,7 +368,6 @@ 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;
@@ -387,7 +393,7 @@ 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);
@@ -396,10 +402,15 @@ 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;
 
+	if (unlikely(wdata->pnfs_error)) {
+		bl_free_short_extents(&BLK_LSEG2EXT(wdata->lseg)->bl_inval,
+					num_se);
+	}
+
 	wdata->task.tk_status = wdata->pnfs_error;
 	wdata->verf.committed = NFS_FILE_SYNC;
 	INIT_WORK(&wdata->task.u.tk_work, bl_write_cleanup);
@@ -552,7 +563,7 @@ 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 */
 
@@ -560,12 +571,15 @@ 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) &
@@ -603,6 +617,19 @@ 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);
@@ -611,10 +638,6 @@ 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;
@@ -638,6 +661,15 @@ 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);
 		}
@@ -685,6 +717,10 @@ out:
 	bl_submit_bio(WRITE, bio);
 	put_parallel(par);
 	return PNFS_ATTEMPTED;
+out_mds:
+	bl_put_extent(be);
+	kfree(par);
+	return PNFS_NOT_ATTEMPTED;
 }
 
 /* FIXME - range ignored */
@@ -711,11 +747,17 @@ static void
 release_inval_marks(struct pnfs_inval_markings *marks)
 {
 	struct pnfs_inval_tracking *pos, *temp;
+	struct pnfs_block_short_extent *se, *stemp;
 
 	list_for_each_entry_safe(pos, temp, &marks->im_tree.mtt_stub, it_link) {
 		list_del(&pos->it_link);
 		kfree(pos);
 	}
+
+	list_for_each_entry_safe(se, stemp, &marks->im_extents, bse_node) {
+		list_del(&se->bse_node);
+		kfree(se);
+	}
 	return;
 }
 
diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h
index 60728acc7b99..e31a2df28e70 100644
--- a/fs/nfs/blocklayout/blocklayout.h
+++ b/fs/nfs/blocklayout/blocklayout.h
@@ -70,6 +70,7 @@ struct pnfs_inval_markings {
 	spinlock_t	im_lock;
 	struct my_tree	im_tree;	/* Sectors that need LAYOUTCOMMIT */
 	sector_t	im_block_size;	/* Server blocksize in sectors */
+	struct list_head im_extents;	/* Short extents for INVAL->RW conversion */
 };
 
 struct pnfs_inval_tracking {
@@ -105,6 +106,7 @@ BL_INIT_INVAL_MARKS(struct pnfs_inval_markings *marks, sector_t blocksize)
 {
 	spin_lock_init(&marks->im_lock);
 	INIT_LIST_HEAD(&marks->im_tree.mtt_stub);
+	INIT_LIST_HEAD(&marks->im_extents);
 	marks->im_block_size = blocksize;
 	marks->im_tree.mtt_step_size = min((sector_t)PAGE_CACHE_SECTORS,
 					   blocksize);
@@ -199,6 +201,11 @@ 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_one_short_extent(struct pnfs_inval_markings *marks);
+void bl_free_short_extents(struct pnfs_inval_markings *marks, int num_to_free);
 
 #endif /* FS_NFS_NFS4BLOCKLAYOUT_H */
diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c
index d0f52ed22428..1abac09f7cd5 100644
--- a/fs/nfs/blocklayout/extents.c
+++ b/fs/nfs/blocklayout/extents.c
@@ -157,10 +157,10 @@ static int _preload_range(struct pnfs_inval_markings *marks,
 			goto out_cleanup;
 	}
 
-	spin_lock(&marks->im_lock);
+	spin_lock_bh(&marks->im_lock);
 	for (s = start; s < end; s += tree->mtt_step_size)
 		used += _add_entry(tree, s, INTERNAL_EXISTS, storage[used]);
-	spin_unlock(&marks->im_lock);
+	spin_unlock_bh(&marks->im_lock);
 
 	status = 0;
 
@@ -179,9 +179,9 @@ int bl_is_sector_init(struct pnfs_inval_markings *marks, sector_t isect)
 {
 	int rv;
 
-	spin_lock(&marks->im_lock);
+	spin_lock_bh(&marks->im_lock);
 	rv = _has_tag(&marks->im_tree, isect, EXTENT_INITIALIZED);
-	spin_unlock(&marks->im_lock);
+	spin_unlock_bh(&marks->im_lock);
 	return rv;
 }
 
@@ -221,9 +221,9 @@ static int is_range_written(struct pnfs_inval_markings *marks,
 {
 	int rv;
 
-	spin_lock(&marks->im_lock);
+	spin_lock_bh(&marks->im_lock);
 	rv = _range_has_tag(&marks->im_tree, start, end, EXTENT_WRITTEN);
-	spin_unlock(&marks->im_lock);
+	spin_unlock_bh(&marks->im_lock);
 	return rv;
 }
 
@@ -244,15 +244,15 @@ int bl_mark_sectors_init(struct pnfs_inval_markings *marks,
 	if (_preload_range(marks, start, end - start))
 		goto outerr;
 
-	spin_lock(&marks->im_lock);
+	spin_lock_bh(&marks->im_lock);
 	if (_set_range(&marks->im_tree, EXTENT_INITIALIZED, offset, length))
 		goto out_unlock;
-	spin_unlock(&marks->im_lock);
+	spin_unlock_bh(&marks->im_lock);
 
 	return 0;
 
 out_unlock:
-	spin_unlock(&marks->im_lock);
+	spin_unlock_bh(&marks->im_lock);
 outerr:
 	return -ENOMEM;
 }
@@ -267,9 +267,9 @@ static int mark_written_sectors(struct pnfs_inval_markings *marks,
 
 	dprintk("%s(offset=%llu,len=%llu) enter\n", __func__,
 		(u64)offset, (u64)length);
-	spin_lock(&marks->im_lock);
+	spin_lock_bh(&marks->im_lock);
 	status = _set_range(&marks->im_tree, EXTENT_WRITTEN, offset, length);
-	spin_unlock(&marks->im_lock);
+	spin_unlock_bh(&marks->im_lock);
 	return status;
 }
 
@@ -369,20 +369,18 @@ 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
@@ -412,9 +410,6 @@ 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;
@@ -862,3 +857,53 @@ clean_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
 		}
 	}
 }
+
+int bl_push_one_short_extent(struct pnfs_inval_markings *marks)
+{
+	struct pnfs_block_short_extent *new;
+
+	new = kmalloc(sizeof(*new), GFP_NOFS);
+	if (unlikely(!new))
+		return -ENOMEM;
+
+	spin_lock_bh(&marks->im_lock);
+	list_add(&new->bse_node, &marks->im_extents);
+	spin_unlock_bh(&marks->im_lock);
+
+	return 0;
+}
+
+struct pnfs_block_short_extent *
+bl_pop_one_short_extent(struct pnfs_inval_markings *marks)
+{
+	struct pnfs_block_short_extent *rv = NULL;
+
+	spin_lock_bh(&marks->im_lock);
+	if (!list_empty(&marks->im_extents)) {
+		rv = list_entry((&marks->im_extents)->next,
+				struct pnfs_block_short_extent, bse_node);
+		list_del_init(&rv->bse_node);
+	}
+	spin_unlock_bh(&marks->im_lock);
+
+	return rv;
+}
+
+void bl_free_short_extents(struct pnfs_inval_markings *marks, int num_to_free)
+{
+	struct pnfs_block_short_extent *se = NULL, *tmp;
+
+	if (num_to_free <= 0)
+		return;
+
+	spin_lock(&marks->im_lock);
+	list_for_each_entry_safe(se, tmp, &marks->im_extents, bse_node) {
+		list_del(&se->bse_node);
+		kfree(se);
+		if (--num_to_free == 0)
+			break;
+	}
+	spin_unlock(&marks->im_lock);
+
+	BUG_ON(num_to_free > 0);
+}