pnfs/blocklayout: rewrite extent tracking

Currently the block layout driver tracks extents in three separate
data structures:

 - the two list of pnfs_block_extent structures returned by the server
 - the list of sectors that were in invalid state but have been written to
 - a list of pnfs_block_short_extent structures for LAYOUTCOMMIT

All of these share the property that they are not only highly inefficient
data structures, but also that operations on them are even more inefficient
than nessecary.

In addition there are various implementation defects like:

 - using an int to track sectors, causing corruption for large offsets
 - incorrect normalization of page or block granularity ranges
 - insufficient error handling
 - incorrect synchronization as extents can be modified while they are in
   use

This patch replace all three data with a single unified rbtree structure
tracking all extents, as well as their in-memory state, although we still
need to instance for read-only and read-write extent due to the arcane
client side COW feature in the block layouts spec.

To fix the problem of extent possibly being modified while in use we make
sure to return a copy of the extent for use in the write path - the
extent can only be invalidated by a layout recall or return which has
to wait until the I/O operations finished due to refcounts on the layout
segment.

The new extent tree work similar to the schemes used by block based
filesystems like XFS or ext4.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 0 insertions, 908 deletions

diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c
deleted file mode 100644
index 4d0161442565..000000000000
--- a/fs/nfs/blocklayout/extents.c
+++ /dev/null
@@ -1,908 +0,0 @@
-/*
- *  linux/fs/nfs/blocklayout/blocklayout.h
- *
- *  Module for the NFSv4.1 pNFS block layout driver.
- *
- *  Copyright (c) 2006 The Regents of the University of Michigan.
- *  All rights reserved.
- *
- *  Andy Adamson <andros@citi.umich.edu>
- *  Fred Isaman <iisaman@umich.edu>
- *
- * permission is granted to use, copy, create derivative works and
- * redistribute this software and such derivative works for any purpose,
- * so long as the name of the university of michigan is not used in
- * any advertising or publicity pertaining to the use or distribution
- * of this software without specific, written prior authorization.  if
- * the above copyright notice or any other identification of the
- * university of michigan is included in any copy of any portion of
- * this software, then the disclaimer below must also be included.
- *
- * this software is provided as is, without representation from the
- * university of michigan as to its fitness for any purpose, and without
- * warranty by the university of michigan of any kind, either express
- * or implied, including without limitation the implied warranties of
- * merchantability and fitness for a particular purpose.  the regents
- * of the university of michigan shall not be liable for any damages,
- * including special, indirect, incidental, or consequential damages,
- * with respect to any claim arising out or in connection with the use
- * of the software, even if it has been or is hereafter advised of the
- * possibility of such damages.
- */
-
-#include "blocklayout.h"
-#define NFSDBG_FACILITY         NFSDBG_PNFS_LD
-
-/* Bit numbers */
-#define EXTENT_INITIALIZED 0
-#define EXTENT_WRITTEN     1
-#define EXTENT_IN_COMMIT   2
-#define INTERNAL_EXISTS    MY_MAX_TAGS
-#define INTERNAL_MASK      ((1 << INTERNAL_EXISTS) - 1)
-
-/* Returns largest t<=s s.t. t%base==0 */
-static inline sector_t normalize(sector_t s, int base)
-{
-	sector_t tmp = s; /* Since do_div modifies its argument */
-	return s - sector_div(tmp, base);
-}
-
-static inline sector_t normalize_up(sector_t s, int base)
-{
-	return normalize(s + base - 1, base);
-}
-
-/* Complete stub using list while determine API wanted */
-
-/* Returns tags, or negative */
-static int32_t _find_entry(struct my_tree *tree, u64 s)
-{
-	struct pnfs_inval_tracking *pos;
-
-	dprintk("%s(%llu) enter\n", __func__, s);
-	list_for_each_entry_reverse(pos, &tree->mtt_stub, it_link) {
-		if (pos->it_sector > s)
-			continue;
-		else if (pos->it_sector == s)
-			return pos->it_tags & INTERNAL_MASK;
-		else
-			break;
-	}
-	return -ENOENT;
-}
-
-static inline
-int _has_tag(struct my_tree *tree, u64 s, int32_t tag)
-{
-	int32_t tags;
-
-	dprintk("%s(%llu, %i) enter\n", __func__, s, tag);
-	s = normalize(s, tree->mtt_step_size);
-	tags = _find_entry(tree, s);
-	if ((tags < 0) || !(tags & (1 << tag)))
-		return 0;
-	else
-		return 1;
-}
-
-/* Creates entry with tag, or if entry already exists, unions tag to it.
- * If storage is not NULL, newly created entry will use it.
- * Returns number of entries added, or negative on error.
- */
-static int _add_entry(struct my_tree *tree, u64 s, int32_t tag,
-		      struct pnfs_inval_tracking *storage)
-{
-	int found = 0;
-	struct pnfs_inval_tracking *pos;
-
-	dprintk("%s(%llu, %i, %p) enter\n", __func__, s, tag, storage);
-	list_for_each_entry_reverse(pos, &tree->mtt_stub, it_link) {
-		if (pos->it_sector > s)
-			continue;
-		else if (pos->it_sector == s) {
-			found = 1;
-			break;
-		} else
-			break;
-	}
-	if (found) {
-		pos->it_tags |= (1 << tag);
-		return 0;
-	} else {
-		struct pnfs_inval_tracking *new;
-		new = storage;
-		new->it_sector = s;
-		new->it_tags = (1 << tag);
-		list_add(&new->it_link, &pos->it_link);
-		return 1;
-	}
-}
-
-/* XXXX Really want option to not create */
-/* Over range, unions tag with existing entries, else creates entry with tag */
-static int _set_range(struct my_tree *tree, int32_t tag, u64 s, u64 length)
-{
-	u64 i;
-
-	dprintk("%s(%i, %llu, %llu) enter\n", __func__, tag, s, length);
-	for (i = normalize(s, tree->mtt_step_size); i < s + length;
-	     i += tree->mtt_step_size)
-		if (_add_entry(tree, i, tag, NULL))
-			return -ENOMEM;
-	return 0;
-}
-
-/* Ensure that future operations on given range of tree will not malloc */
-static int _preload_range(struct pnfs_inval_markings *marks,
-		u64 offset, u64 length)
-{
-	u64 start, end, s;
-	int count, i, used = 0, status = -ENOMEM;
-	struct pnfs_inval_tracking **storage;
-	struct my_tree  *tree = &marks->im_tree;
-
-	dprintk("%s(%llu, %llu) enter\n", __func__, offset, length);
-	start = normalize(offset, tree->mtt_step_size);
-	end = normalize_up(offset + length, tree->mtt_step_size);
-	count = (int)(end - start) / (int)tree->mtt_step_size;
-
-	/* Pre-malloc what memory we might need */
-	storage = kcalloc(count, sizeof(*storage), GFP_NOFS);
-	if (!storage)
-		return -ENOMEM;
-	for (i = 0; i < count; i++) {
-		storage[i] = kmalloc(sizeof(struct pnfs_inval_tracking),
-				     GFP_NOFS);
-		if (!storage[i])
-			goto out_cleanup;
-	}
-
-	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_bh(&marks->im_lock);
-
-	status = 0;
-
- out_cleanup:
-	for (i = used; i < count; i++) {
-		if (!storage[i])
-			break;
-		kfree(storage[i]);
-	}
-	kfree(storage);
-	return status;
-}
-
-/* We are relying on page lock to serialize this */
-int bl_is_sector_init(struct pnfs_inval_markings *marks, sector_t isect)
-{
-	int rv;
-
-	spin_lock_bh(&marks->im_lock);
-	rv = _has_tag(&marks->im_tree, isect, EXTENT_INITIALIZED);
-	spin_unlock_bh(&marks->im_lock);
-	return rv;
-}
-
-/* Assume start, end already sector aligned */
-static int
-_range_has_tag(struct my_tree *tree, u64 start, u64 end, int32_t tag)
-{
-	struct pnfs_inval_tracking *pos;
-	u64 expect = 0;
-
-	dprintk("%s(%llu, %llu, %i) enter\n", __func__, start, end, tag);
-	list_for_each_entry_reverse(pos, &tree->mtt_stub, it_link) {
-		if (pos->it_sector >= end)
-			continue;
-		if (!expect) {
-			if ((pos->it_sector == end - tree->mtt_step_size) &&
-			    (pos->it_tags & (1 << tag))) {
-				expect = pos->it_sector - tree->mtt_step_size;
-				if (pos->it_sector < tree->mtt_step_size || expect < start)
-					return 1;
-				continue;
-			} else {
-				return 0;
-			}
-		}
-		if (pos->it_sector != expect || !(pos->it_tags & (1 << tag)))
-			return 0;
-		expect -= tree->mtt_step_size;
-		if (expect < start)
-			return 1;
-	}
-	return 0;
-}
-
-static int is_range_written(struct pnfs_inval_markings *marks,
-			    sector_t start, sector_t end)
-{
-	int rv;
-
-	spin_lock_bh(&marks->im_lock);
-	rv = _range_has_tag(&marks->im_tree, start, end, EXTENT_WRITTEN);
-	spin_unlock_bh(&marks->im_lock);
-	return rv;
-}
-
-/* Marks sectors in [offest, offset_length) as having been initialized.
- * All lengths are step-aligned, where step is min(pagesize, blocksize).
- * Currently assumes offset is page-aligned
- */
-int bl_mark_sectors_init(struct pnfs_inval_markings *marks,
-			     sector_t offset, sector_t length)
-{
-	sector_t start, end;
-
-	dprintk("%s(offset=%llu,len=%llu) enter\n",
-		__func__, (u64)offset, (u64)length);
-
-	start = normalize(offset, marks->im_block_size);
-	end = normalize_up(offset + length, marks->im_block_size);
-	if (_preload_range(marks, start, end - start))
-		goto outerr;
-
-	spin_lock_bh(&marks->im_lock);
-	if (_set_range(&marks->im_tree, EXTENT_INITIALIZED, offset, length))
-		goto out_unlock;
-	spin_unlock_bh(&marks->im_lock);
-
-	return 0;
-
-out_unlock:
-	spin_unlock_bh(&marks->im_lock);
-outerr:
-	return -ENOMEM;
-}
-
-/* Marks sectors in [offest, offset+length) as having been written to disk.
- * All lengths should be block aligned.
- */
-static int mark_written_sectors(struct pnfs_inval_markings *marks,
-				sector_t offset, sector_t length)
-{
-	int status;
-
-	dprintk("%s(offset=%llu,len=%llu) enter\n", __func__,
-		(u64)offset, (u64)length);
-	spin_lock_bh(&marks->im_lock);
-	status = _set_range(&marks->im_tree, EXTENT_WRITTEN, offset, length);
-	spin_unlock_bh(&marks->im_lock);
-	return status;
-}
-
-static void print_short_extent(struct pnfs_block_short_extent *be)
-{
-	dprintk("PRINT SHORT EXTENT extent %p\n", be);
-	if (be) {
-		dprintk("        be_f_offset %llu\n", (u64)be->bse_f_offset);
-		dprintk("        be_length   %llu\n", (u64)be->bse_length);
-	}
-}
-
-static void print_clist(struct list_head *list, unsigned int count)
-{
-	struct pnfs_block_short_extent *be;
-	unsigned int i = 0;
-
-	ifdebug(FACILITY) {
-		printk(KERN_DEBUG "****************\n");
-		printk(KERN_DEBUG "Extent list looks like:\n");
-		list_for_each_entry(be, list, bse_node) {
-			i++;
-			print_short_extent(be);
-		}
-		if (i != count)
-			printk(KERN_DEBUG "\n\nExpected %u entries\n\n\n", count);
-		printk(KERN_DEBUG "****************\n");
-	}
-}
-
-/* Note: In theory, we should do more checking that devid's match between
- * old and new, but if they don't, the lists are too corrupt to salvage anyway.
- */
-/* Note this is very similar to bl_add_merge_extent */
-static void add_to_commitlist(struct pnfs_block_layout *bl,
-			      struct pnfs_block_short_extent *new)
-{
-	struct list_head *clist = &bl->bl_commit;
-	struct pnfs_block_short_extent *old, *save;
-	sector_t end = new->bse_f_offset + new->bse_length;
-
-	dprintk("%s enter\n", __func__);
-	print_short_extent(new);
-	print_clist(clist, bl->bl_count);
-	bl->bl_count++;
-	/* Scan for proper place to insert, extending new to the left
-	 * as much as possible.
-	 */
-	list_for_each_entry_safe(old, save, clist, bse_node) {
-		if (new->bse_f_offset < old->bse_f_offset)
-			break;
-		if (end <= old->bse_f_offset + old->bse_length) {
-			/* Range is already in list */
-			bl->bl_count--;
-			kfree(new);
-			return;
-		} else if (new->bse_f_offset <=
-				old->bse_f_offset + old->bse_length) {
-			/* new overlaps or abuts existing be */
-			if (new->bse_mdev == old->bse_mdev) {
-				/* extend new to fully replace old */
-				new->bse_length += new->bse_f_offset -
-						old->bse_f_offset;
-				new->bse_f_offset = old->bse_f_offset;
-				list_del(&old->bse_node);
-				bl->bl_count--;
-				kfree(old);
-			}
-		}
-	}
-	/* Note that if we never hit the above break, old will not point to a
-	 * valid extent.  However, in that case &old->bse_node==list.
-	 */
-	list_add_tail(&new->bse_node, &old->bse_node);
-	/* Scan forward for overlaps.  If we find any, extend new and
-	 * remove the overlapped extent.
-	 */
-	old = list_prepare_entry(new, clist, bse_node);
-	list_for_each_entry_safe_continue(old, save, clist, bse_node) {
-		if (end < old->bse_f_offset)
-			break;
-		/* new overlaps or abuts old */
-		if (new->bse_mdev == old->bse_mdev) {
-			if (end < old->bse_f_offset + old->bse_length) {
-				/* extend new to fully cover old */
-				end = old->bse_f_offset + old->bse_length;
-				new->bse_length = end - new->bse_f_offset;
-			}
-			list_del(&old->bse_node);
-			bl->bl_count--;
-			kfree(old);
-		}
-	}
-	dprintk("%s: after merging\n", __func__);
-	print_clist(clist, bl->bl_count);
-}
-
-/* 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,
-		    struct pnfs_block_short_extent *new)
-{
-	sector_t new_end, end = offset + length;
-	struct pnfs_block_layout *bl = container_of(be->be_inval,
-						    struct pnfs_block_layout,
-						    bl_inval);
-
-	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
-	 * been entirely written to disk.
-	 */
-	new->bse_f_offset = offset;
-	offset = normalize(offset, bl->bl_blocksize);
-	if (offset < new->bse_f_offset) {
-		if (is_range_written(be->be_inval, offset, new->bse_f_offset))
-			new->bse_f_offset = offset;
-		else
-			new->bse_f_offset = offset + bl->bl_blocksize;
-	}
-	new_end = normalize_up(end, bl->bl_blocksize);
-	if (end < new_end) {
-		if (is_range_written(be->be_inval, end, new_end))
-			end = new_end;
-		else
-			end = new_end - bl->bl_blocksize;
-	}
-	if (end <= new->bse_f_offset) {
-		kfree(new);
-		return 0;
-	}
-	new->bse_length = end - new->bse_f_offset;
-	new->bse_devid = be->be_devid;
-	new->bse_mdev = be->be_mdev;
-
-	spin_lock(&bl->bl_ext_lock);
-	add_to_commitlist(bl, new);
-	spin_unlock(&bl->bl_ext_lock);
-	return 0;
-}
-
-static void print_bl_extent(struct pnfs_block_extent *be)
-{
-	dprintk("PRINT EXTENT extent %p\n", be);
-	if (be) {
-		dprintk("        be_f_offset %llu\n", (u64)be->be_f_offset);
-		dprintk("        be_length   %llu\n", (u64)be->be_length);
-		dprintk("        be_v_offset %llu\n", (u64)be->be_v_offset);
-		dprintk("        be_state    %d\n", be->be_state);
-	}
-}
-
-static void
-destroy_extent(struct kref *kref)
-{
-	struct pnfs_block_extent *be;
-
-	be = container_of(kref, struct pnfs_block_extent, be_refcnt);
-	dprintk("%s be=%p\n", __func__, be);
-	kfree(be);
-}
-
-void
-bl_put_extent(struct pnfs_block_extent *be)
-{
-	if (be) {
-		dprintk("%s enter %p (%i)\n", __func__, be,
-			atomic_read(&be->be_refcnt.refcount));
-		kref_put(&be->be_refcnt, destroy_extent);
-	}
-}
-
-struct pnfs_block_extent *bl_alloc_extent(void)
-{
-	struct pnfs_block_extent *be;
-
-	be = kmalloc(sizeof(struct pnfs_block_extent), GFP_NOFS);
-	if (!be)
-		return NULL;
-	INIT_LIST_HEAD(&be->be_node);
-	kref_init(&be->be_refcnt);
-	be->be_inval = NULL;
-	return be;
-}
-
-static void print_elist(struct list_head *list)
-{
-	struct pnfs_block_extent *be;
-	dprintk("****************\n");
-	dprintk("Extent list looks like:\n");
-	list_for_each_entry(be, list, be_node) {
-		print_bl_extent(be);
-	}
-	dprintk("****************\n");
-}
-
-static inline int
-extents_consistent(struct pnfs_block_extent *old, struct pnfs_block_extent *new)
-{
-	/* Note this assumes new->be_f_offset >= old->be_f_offset */
-	return (new->be_state == old->be_state) &&
-		((new->be_state == PNFS_BLOCK_NONE_DATA) ||
-		 ((new->be_v_offset - old->be_v_offset ==
-		   new->be_f_offset - old->be_f_offset) &&
-		  new->be_mdev == old->be_mdev));
-}
-
-/* Adds new to appropriate list in bl, modifying new and removing existing
- * extents as appropriate to deal with overlaps.
- *
- * See bl_find_get_extent for list constraints.
- *
- * Refcount on new is already set.  If end up not using it, or error out,
- * need to put the reference.
- *
- * bl->bl_ext_lock is held by caller.
- */
-int
-bl_add_merge_extent(struct pnfs_block_layout *bl,
-		     struct pnfs_block_extent *new)
-{
-	struct pnfs_block_extent *be, *tmp;
-	sector_t end = new->be_f_offset + new->be_length;
-	struct list_head *list;
-
-	dprintk("%s enter with be=%p\n", __func__, new);
-	print_bl_extent(new);
-	list = &bl->bl_extents[bl_choose_list(new->be_state)];
-	print_elist(list);
-
-	/* Scan for proper place to insert, extending new to the left
-	 * as much as possible.
-	 */
-	list_for_each_entry_safe_reverse(be, tmp, list, be_node) {
-		if (new->be_f_offset >= be->be_f_offset + be->be_length)
-			break;
-		if (new->be_f_offset >= be->be_f_offset) {
-			if (end <= be->be_f_offset + be->be_length) {
-				/* new is a subset of existing be*/
-				if (extents_consistent(be, new)) {
-					dprintk("%s: new is subset, ignoring\n",
-						__func__);
-					bl_put_extent(new);
-					return 0;
-				} else {
-					goto out_err;
-				}
-			} else {
-				/* |<--   be   -->|
-				 *          |<--   new   -->| */
-				if (extents_consistent(be, new)) {
-					/* extend new to fully replace be */
-					new->be_length += new->be_f_offset -
-						be->be_f_offset;
-					new->be_f_offset = be->be_f_offset;
-					new->be_v_offset = be->be_v_offset;
-					dprintk("%s: removing %p\n", __func__, be);
-					list_del(&be->be_node);
-					bl_put_extent(be);
-				} else {
-					goto out_err;
-				}
-			}
-		} else if (end >= be->be_f_offset + be->be_length) {
-			/* new extent overlap existing be */
-			if (extents_consistent(be, new)) {
-				/* extend new to fully replace be */
-				dprintk("%s: removing %p\n", __func__, be);
-				list_del(&be->be_node);
-				bl_put_extent(be);
-			} else {
-				goto out_err;
-			}
-		} else if (end > be->be_f_offset) {
-			/*           |<--   be   -->|
-			 *|<--   new   -->| */
-			if (extents_consistent(new, be)) {
-				/* extend new to fully replace be */
-				new->be_length += be->be_f_offset + be->be_length -
-					new->be_f_offset - new->be_length;
-				dprintk("%s: removing %p\n", __func__, be);
-				list_del(&be->be_node);
-				bl_put_extent(be);
-			} else {
-				goto out_err;
-			}
-		}
-	}
-	/* Note that if we never hit the above break, be will not point to a
-	 * valid extent.  However, in that case &be->be_node==list.
-	 */
-	list_add(&new->be_node, &be->be_node);
-	dprintk("%s: inserting new\n", __func__);
-	print_elist(list);
-	/* FIXME - The per-list consistency checks have all been done,
-	 * should now check cross-list consistency.
-	 */
-	return 0;
-
- out_err:
-	bl_put_extent(new);
-	return -EIO;
-}
-
-/* Returns extent, or NULL.  If a second READ extent exists, it is returned
- * in cow_read, if given.
- *
- * The extents are kept in two seperate ordered lists, one for READ and NONE,
- * one for READWRITE and INVALID.  Within each list, we assume:
- * 1. Extents are ordered by file offset.
- * 2. For any given isect, there is at most one extents that matches.
- */
-struct pnfs_block_extent *
-bl_find_get_extent(struct pnfs_block_layout *bl, sector_t isect,
-	    struct pnfs_block_extent **cow_read)
-{
-	struct pnfs_block_extent *be, *cow, *ret;
-	int i;
-
-	dprintk("%s enter with isect %llu\n", __func__, (u64)isect);
-	cow = ret = NULL;
-	spin_lock(&bl->bl_ext_lock);
-	for (i = 0; i < EXTENT_LISTS; i++) {
-		list_for_each_entry_reverse(be, &bl->bl_extents[i], be_node) {
-			if (isect >= be->be_f_offset + be->be_length)
-				break;
-			if (isect >= be->be_f_offset) {
-				/* We have found an extent */
-				dprintk("%s Get %p (%i)\n", __func__, be,
-					atomic_read(&be->be_refcnt.refcount));
-				kref_get(&be->be_refcnt);
-				if (!ret)
-					ret = be;
-				else if (be->be_state != PNFS_BLOCK_READ_DATA)
-					bl_put_extent(be);
-				else
-					cow = be;
-				break;
-			}
-		}
-		if (ret &&
-		    (!cow_read || ret->be_state != PNFS_BLOCK_INVALID_DATA))
-			break;
-	}
-	spin_unlock(&bl->bl_ext_lock);
-	if (cow_read)
-		*cow_read = cow;
-	print_bl_extent(ret);
-	return ret;
-}
-
-/* Similar to bl_find_get_extent, but called with lock held, and ignores cow */
-static struct pnfs_block_extent *
-bl_find_get_extent_locked(struct pnfs_block_layout *bl, sector_t isect)
-{
-	struct pnfs_block_extent *be, *ret = NULL;
-	int i;
-
-	dprintk("%s enter with isect %llu\n", __func__, (u64)isect);
-	for (i = 0; i < EXTENT_LISTS; i++) {
-		if (ret)
-			break;
-		list_for_each_entry_reverse(be, &bl->bl_extents[i], be_node) {
-			if (isect >= be->be_f_offset + be->be_length)
-				break;
-			if (isect >= be->be_f_offset) {
-				/* We have found an extent */
-				dprintk("%s Get %p (%i)\n", __func__, be,
-					atomic_read(&be->be_refcnt.refcount));
-				kref_get(&be->be_refcnt);
-				ret = be;
-				break;
-			}
-		}
-	}
-	print_bl_extent(ret);
-	return ret;
-}
-
-int
-encode_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
-			       struct xdr_stream *xdr,
-			       const struct nfs4_layoutcommit_args *arg)
-{
-	struct pnfs_block_short_extent *lce, *save;
-	unsigned int count = 0;
-	__be32 *p, *xdr_start;
-
-	dprintk("%s enter\n", __func__);
-	/* BUG - creation of bl_commit is buggy - need to wait for
-	 * entire block to be marked WRITTEN before it can be added.
-	 */
-	spin_lock(&bl->bl_ext_lock);
-	/* Want to adjust for possible truncate */
-	/* We now want to adjust argument range */
-
-	/* XDR encode the ranges found */
-	xdr_start = xdr_reserve_space(xdr, 8);
-	if (!xdr_start)
-		goto out;
-	list_for_each_entry_safe(lce, save, &bl->bl_commit, bse_node) {
-		p = xdr_reserve_space(xdr, 7 * 4 + sizeof(lce->bse_devid.data));
-		if (!p)
-			break;
-		p = xdr_encode_opaque_fixed(p, lce->bse_devid.data, NFS4_DEVICEID4_SIZE);
-		p = xdr_encode_hyper(p, lce->bse_f_offset << SECTOR_SHIFT);
-		p = xdr_encode_hyper(p, lce->bse_length << SECTOR_SHIFT);
-		p = xdr_encode_hyper(p, 0LL);
-		*p++ = cpu_to_be32(PNFS_BLOCK_READWRITE_DATA);
-		list_move_tail(&lce->bse_node, &bl->bl_committing);
-		bl->bl_count--;
-		count++;
-	}
-	xdr_start[0] = cpu_to_be32((xdr->p - xdr_start - 1) * 4);
-	xdr_start[1] = cpu_to_be32(count);
-out:
-	spin_unlock(&bl->bl_ext_lock);
-	dprintk("%s found %i ranges\n", __func__, count);
-	return 0;
-}
-
-/* Helper function to set_to_rw that initialize a new extent */
-static void
-_prep_new_extent(struct pnfs_block_extent *new,
-		 struct pnfs_block_extent *orig,
-		 sector_t offset, sector_t length, int state)
-{
-	kref_init(&new->be_refcnt);
-	/* don't need to INIT_LIST_HEAD(&new->be_node) */
-	memcpy(&new->be_devid, &orig->be_devid, sizeof(struct nfs4_deviceid));
-	new->be_mdev = orig->be_mdev;
-	new->be_f_offset = offset;
-	new->be_length = length;
-	new->be_v_offset = orig->be_v_offset - orig->be_f_offset + offset;
-	new->be_state = state;
-	new->be_inval = orig->be_inval;
-}
-
-/* Tries to merge be with extent in front of it in list.
- * Frees storage if not used.
- */
-static struct pnfs_block_extent *
-_front_merge(struct pnfs_block_extent *be, struct list_head *head,
-	     struct pnfs_block_extent *storage)
-{
-	struct pnfs_block_extent *prev;
-
-	if (!storage)
-		goto no_merge;
-	if (&be->be_node == head || be->be_node.prev == head)
-		goto no_merge;
-	prev = list_entry(be->be_node.prev, struct pnfs_block_extent, be_node);
-	if ((prev->be_f_offset + prev->be_length != be->be_f_offset) ||
-	    !extents_consistent(prev, be))
-		goto no_merge;
-	_prep_new_extent(storage, prev, prev->be_f_offset,
-			 prev->be_length + be->be_length, prev->be_state);
-	list_replace(&prev->be_node, &storage->be_node);
-	bl_put_extent(prev);
-	list_del(&be->be_node);
-	bl_put_extent(be);
-	return storage;
-
- no_merge:
-	kfree(storage);
-	return be;
-}
-
-static u64
-set_to_rw(struct pnfs_block_layout *bl, u64 offset, u64 length)
-{
-	u64 rv = offset + length;
-	struct pnfs_block_extent *be, *e1, *e2, *e3, *new, *old;
-	struct pnfs_block_extent *children[3];
-	struct pnfs_block_extent *merge1 = NULL, *merge2 = NULL;
-	int i = 0, j;
-
-	dprintk("%s(%llu, %llu)\n", __func__, offset, length);
-	/* Create storage for up to three new extents e1, e2, e3 */
-	e1 = kmalloc(sizeof(*e1), GFP_ATOMIC);
-	e2 = kmalloc(sizeof(*e2), GFP_ATOMIC);
-	e3 = kmalloc(sizeof(*e3), GFP_ATOMIC);
-	/* BUG - we are ignoring any failure */
-	if (!e1 || !e2 || !e3)
-		goto out_nosplit;
-
-	spin_lock(&bl->bl_ext_lock);
-	be = bl_find_get_extent_locked(bl, offset);
-	rv = be->be_f_offset + be->be_length;
-	if (be->be_state != PNFS_BLOCK_INVALID_DATA) {
-		spin_unlock(&bl->bl_ext_lock);
-		goto out_nosplit;
-	}
-	/* Add e* to children, bumping e*'s krefs */
-	if (be->be_f_offset != offset) {
-		_prep_new_extent(e1, be, be->be_f_offset,
-				 offset - be->be_f_offset,
-				 PNFS_BLOCK_INVALID_DATA);
-		children[i++] = e1;
-		print_bl_extent(e1);
-	} else
-		merge1 = e1;
-	_prep_new_extent(e2, be, offset,
-			 min(length, be->be_f_offset + be->be_length - offset),
-			 PNFS_BLOCK_READWRITE_DATA);
-	children[i++] = e2;
-	print_bl_extent(e2);
-	if (offset + length < be->be_f_offset + be->be_length) {
-		_prep_new_extent(e3, be, e2->be_f_offset + e2->be_length,
-				 be->be_f_offset + be->be_length -
-				 offset - length,
-				 PNFS_BLOCK_INVALID_DATA);
-		children[i++] = e3;
-		print_bl_extent(e3);
-	} else
-		merge2 = e3;
-
-	/* Remove be from list, and insert the e* */
-	/* We don't get refs on e*, since this list is the base reference
-	 * set when init'ed.
-	 */
-	if (i < 3)
-		children[i] = NULL;
-	new = children[0];
-	list_replace(&be->be_node, &new->be_node);
-	bl_put_extent(be);
-	new = _front_merge(new, &bl->bl_extents[RW_EXTENT], merge1);
-	for (j = 1; j < i; j++) {
-		old = new;
-		new = children[j];
-		list_add(&new->be_node, &old->be_node);
-	}
-	if (merge2) {
-		/* This is a HACK, should just create a _back_merge function */
-		new = list_entry(new->be_node.next,
-				 struct pnfs_block_extent, be_node);
-		new = _front_merge(new, &bl->bl_extents[RW_EXTENT], merge2);
-	}
-	spin_unlock(&bl->bl_ext_lock);
-
-	/* Since we removed the base reference above, be is now scheduled for
-	 * destruction.
-	 */
-	bl_put_extent(be);
-	dprintk("%s returns %llu after split\n", __func__, rv);
-	return rv;
-
- out_nosplit:
-	kfree(e1);
-	kfree(e2);
-	kfree(e3);
-	dprintk("%s returns %llu without splitting\n", __func__, rv);
-	return rv;
-}
-
-void
-clean_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
-			      const struct nfs4_layoutcommit_args *arg,
-			      int status)
-{
-	struct pnfs_block_short_extent *lce, *save;
-
-	dprintk("%s status %d\n", __func__, status);
-	list_for_each_entry_safe(lce, save, &bl->bl_committing, bse_node) {
-		if (likely(!status)) {
-			u64 offset = lce->bse_f_offset;
-			u64 end = offset + lce->bse_length;
-
-			do {
-				offset = set_to_rw(bl, offset, end - offset);
-			} while (offset < end);
-			list_del(&lce->bse_node);
-
-			kfree(lce);
-		} else {
-			list_del(&lce->bse_node);
-			spin_lock(&bl->bl_ext_lock);
-			add_to_commitlist(bl, lce);
-			spin_unlock(&bl->bl_ext_lock);
-		}
-	}
-}
-
-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);
-}