These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

17 files changed, 323 insertions, 206 deletions

diff --git a/kernel/fs/nilfs2/alloc.c b/kernel/fs/nilfs2/alloc.c
index 8df0f3b78..2ccbf5531 100644
--- a/kernel/fs/nilfs2/alloc.c
+++ b/kernel/fs/nilfs2/alloc.c
@@ -133,38 +133,38 @@ nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
 
 /**
  * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
- * @inode: inode of metadata file using this allocator
- * @group: group number
  * @desc: pointer to descriptor structure for the group
+ * @lock: spin lock protecting @desc
  */
 static unsigned long
-nilfs_palloc_group_desc_nfrees(struct inode *inode, unsigned long group,
-			       const struct nilfs_palloc_group_desc *desc)
+nilfs_palloc_group_desc_nfrees(const struct nilfs_palloc_group_desc *desc,
+			       spinlock_t *lock)
 {
 	unsigned long nfree;
 
-	spin_lock(nilfs_mdt_bgl_lock(inode, group));
+	spin_lock(lock);
 	nfree = le32_to_cpu(desc->pg_nfrees);
-	spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+	spin_unlock(lock);
 	return nfree;
 }
 
 /**
  * nilfs_palloc_group_desc_add_entries - adjust count of free entries
- * @inode: inode of metadata file using this allocator
- * @group: group number
  * @desc: pointer to descriptor structure for the group
+ * @lock: spin lock protecting @desc
  * @n: delta to be added
  */
-static void
-nilfs_palloc_group_desc_add_entries(struct inode *inode,
-				    unsigned long group,
-				    struct nilfs_palloc_group_desc *desc,
-				    u32 n)
+static u32
+nilfs_palloc_group_desc_add_entries(struct nilfs_palloc_group_desc *desc,
+				    spinlock_t *lock, u32 n)
 {
-	spin_lock(nilfs_mdt_bgl_lock(inode, group));
+	u32 nfree;
+
+	spin_lock(lock);
 	le32_add_cpu(&desc->pg_nfrees, n);
-	spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+	nfree = le32_to_cpu(desc->pg_nfrees);
+	spin_unlock(lock);
+	return nfree;
 }
 
 /**
@@ -240,6 +240,26 @@ static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,
 }
 
 /**
+ * nilfs_palloc_delete_block - delete a block on the persistent allocator file
+ * @inode: inode of metadata file using this allocator
+ * @blkoff: block offset
+ * @prev: nilfs_bh_assoc struct of the last used buffer
+ * @lock: spin lock protecting @prev
+ */
+static int nilfs_palloc_delete_block(struct inode *inode, unsigned long blkoff,
+				     struct nilfs_bh_assoc *prev,
+				     spinlock_t *lock)
+{
+	spin_lock(lock);
+	if (prev->bh && blkoff == prev->blkoff) {
+		brelse(prev->bh);
+		prev->bh = NULL;
+	}
+	spin_unlock(lock);
+	return nilfs_mdt_delete_block(inode, blkoff);
+}
+
+/**
  * nilfs_palloc_get_desc_block - get buffer head of a group descriptor block
  * @inode: inode of metadata file using this allocator
  * @group: group number
@@ -278,6 +298,22 @@ static int nilfs_palloc_get_bitmap_block(struct inode *inode,
 }
 
 /**
+ * nilfs_palloc_delete_bitmap_block - delete a bitmap block
+ * @inode: inode of metadata file using this allocator
+ * @group: group number
+ */
+static int nilfs_palloc_delete_bitmap_block(struct inode *inode,
+					    unsigned long group)
+{
+	struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+	return nilfs_palloc_delete_block(inode,
+					 nilfs_palloc_bitmap_blkoff(inode,
+								    group),
+					 &cache->prev_bitmap, &cache->lock);
+}
+
+/**
  * nilfs_palloc_get_entry_block - get buffer head of an entry block
  * @inode: inode of metadata file using this allocator
  * @nr: serial number of the entry (e.g. inode number)
@@ -296,6 +332,20 @@ int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
 }
 
 /**
+ * nilfs_palloc_delete_entry_block - delete an entry block
+ * @inode: inode of metadata file using this allocator
+ * @nr: serial number of the entry
+ */
+static int nilfs_palloc_delete_entry_block(struct inode *inode, __u64 nr)
+{
+	struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+	return nilfs_palloc_delete_block(inode,
+					 nilfs_palloc_entry_blkoff(inode, nr),
+					 &cache->prev_entry, &cache->lock);
+}
+
+/**
  * nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor
  * @inode: inode of metadata file using this allocator
  * @group: group number
@@ -332,51 +382,40 @@ void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
 
 /**
  * nilfs_palloc_find_available_slot - find available slot in a group
- * @inode: inode of metadata file using this allocator
- * @group: group number
- * @target: offset number of an entry in the group (start point)
  * @bitmap: bitmap of the group
+ * @target: offset number of an entry in the group (start point)
  * @bsize: size in bits
+ * @lock: spin lock protecting @bitmap
  */
-static int nilfs_palloc_find_available_slot(struct inode *inode,
-					    unsigned long group,
+static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
 					    unsigned long target,
-					    unsigned char *bitmap,
-					    int bsize)
-{
-	int curr, pos, end, i;
-
-	if (target > 0) {
-		end = (target + BITS_PER_LONG - 1) & ~(BITS_PER_LONG - 1);
-		if (end > bsize)
-			end = bsize;
-		pos = nilfs_find_next_zero_bit(bitmap, end, target);
-		if (pos < end &&
-		    !nilfs_set_bit_atomic(
-			    nilfs_mdt_bgl_lock(inode, group), pos, bitmap))
-			return pos;
-	} else
-		end = 0;
-
-	for (i = 0, curr = end;
-	     i < bsize;
-	     i += BITS_PER_LONG, curr += BITS_PER_LONG) {
-		/* wrap around */
-		if (curr >= bsize)
-			curr = 0;
-		while (*((unsigned long *)bitmap + curr / BITS_PER_LONG)
-		       != ~0UL) {
-			end = curr + BITS_PER_LONG;
-			if (end > bsize)
-				end = bsize;
-			pos = nilfs_find_next_zero_bit(bitmap, end, curr);
-			if ((pos < end) &&
-			    !nilfs_set_bit_atomic(
-				    nilfs_mdt_bgl_lock(inode, group), pos,
-				    bitmap))
+					    unsigned bsize,
+					    spinlock_t *lock)
+{
+	int pos, end = bsize;
+
+	if (likely(target < bsize)) {
+		pos = target;
+		do {
+			pos = nilfs_find_next_zero_bit(bitmap, end, pos);
+			if (pos >= end)
+				break;
+			if (!nilfs_set_bit_atomic(lock, pos, bitmap))
 				return pos;
-		}
+		} while (++pos < end);
+
+		end = target;
+	}
+
+	/* wrap around */
+	for (pos = 0; pos < end; pos++) {
+		pos = nilfs_find_next_zero_bit(bitmap, end, pos);
+		if (pos >= end)
+			break;
+		if (!nilfs_set_bit_atomic(lock, pos, bitmap))
+			return pos;
 	}
+
 	return -ENOSPC;
 }
 
@@ -475,15 +514,15 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
 	void *desc_kaddr, *bitmap_kaddr;
 	unsigned long group, maxgroup, ngroups;
 	unsigned long group_offset, maxgroup_offset;
-	unsigned long n, entries_per_group, groups_per_desc_block;
+	unsigned long n, entries_per_group;
 	unsigned long i, j;
+	spinlock_t *lock;
 	int pos, ret;
 
 	ngroups = nilfs_palloc_groups_count(inode);
 	maxgroup = ngroups - 1;
 	group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 	entries_per_group = nilfs_palloc_entries_per_group(inode);
-	groups_per_desc_block = nilfs_palloc_groups_per_desc_block(inode);
 
 	for (i = 0; i < ngroups; i += n) {
 		if (group >= ngroups) {
@@ -501,8 +540,8 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
 		n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
 							   maxgroup);
 		for (j = 0; j < n; j++, desc++, group++) {
-			if (nilfs_palloc_group_desc_nfrees(inode, group, desc)
-			    > 0) {
+			lock = nilfs_mdt_bgl_lock(inode, group);
+			if (nilfs_palloc_group_desc_nfrees(desc, lock) > 0) {
 				ret = nilfs_palloc_get_bitmap_block(
 					inode, group, 1, &bitmap_bh);
 				if (ret < 0)
@@ -510,12 +549,12 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
 				bitmap_kaddr = kmap(bitmap_bh->b_page);
 				bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
 				pos = nilfs_palloc_find_available_slot(
-					inode, group, group_offset, bitmap,
-					entries_per_group);
+					bitmap, group_offset,
+					entries_per_group, lock);
 				if (pos >= 0) {
 					/* found a free entry */
 					nilfs_palloc_group_desc_add_entries(
-						inode, group, desc, -1);
+						desc, lock, -1);
 					req->pr_entry_nr =
 						entries_per_group * group + pos;
 					kunmap(desc_bh->b_page);
@@ -573,6 +612,7 @@ void nilfs_palloc_commit_free_entry(struct inode *inode,
 	unsigned long group, group_offset;
 	unsigned char *bitmap;
 	void *desc_kaddr, *bitmap_kaddr;
+	spinlock_t *lock;
 
 	group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 	desc_kaddr = kmap(req->pr_desc_bh->b_page);
@@ -580,13 +620,15 @@ void nilfs_palloc_commit_free_entry(struct inode *inode,
 						 req->pr_desc_bh, desc_kaddr);
 	bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
 	bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
+	lock = nilfs_mdt_bgl_lock(inode, group);
 
-	if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
-				    group_offset, bitmap))
-		printk(KERN_WARNING "%s: entry number %llu already freed\n",
-		       __func__, (unsigned long long)req->pr_entry_nr);
+	if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
+		nilfs_warning(inode->i_sb, __func__,
+			      "entry number %llu already freed: ino=%lu\n",
+			      (unsigned long long)req->pr_entry_nr,
+			      (unsigned long)inode->i_ino);
 	else
-		nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+		nilfs_palloc_group_desc_add_entries(desc, lock, 1);
 
 	kunmap(req->pr_bitmap_bh->b_page);
 	kunmap(req->pr_desc_bh->b_page);
@@ -611,6 +653,7 @@ void nilfs_palloc_abort_alloc_entry(struct inode *inode,
 	void *desc_kaddr, *bitmap_kaddr;
 	unsigned char *bitmap;
 	unsigned long group, group_offset;
+	spinlock_t *lock;
 
 	group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 	desc_kaddr = kmap(req->pr_desc_bh->b_page);
@@ -618,12 +661,15 @@ void nilfs_palloc_abort_alloc_entry(struct inode *inode,
 						 req->pr_desc_bh, desc_kaddr);
 	bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
 	bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
-	if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
-				    group_offset, bitmap))
-		printk(KERN_WARNING "%s: entry number %llu already freed\n",
-		       __func__, (unsigned long long)req->pr_entry_nr);
+	lock = nilfs_mdt_bgl_lock(inode, group);
+
+	if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
+		nilfs_warning(inode->i_sb, __func__,
+			      "entry number %llu already freed: ino=%lu\n",
+			      (unsigned long long)req->pr_entry_nr,
+			      (unsigned long)inode->i_ino);
 	else
-		nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+		nilfs_palloc_group_desc_add_entries(desc, lock, 1);
 
 	kunmap(req->pr_bitmap_bh->b_page);
 	kunmap(req->pr_desc_bh->b_page);
@@ -680,22 +726,6 @@ void nilfs_palloc_abort_free_entry(struct inode *inode,
 }
 
 /**
- * nilfs_palloc_group_is_in - judge if an entry is in a group
- * @inode: inode of metadata file using this allocator
- * @group: group number
- * @nr: serial number of the entry (e.g. inode number)
- */
-static int
-nilfs_palloc_group_is_in(struct inode *inode, unsigned long group, __u64 nr)
-{
-	__u64 first, last;
-
-	first = group * nilfs_palloc_entries_per_group(inode);
-	last = first + nilfs_palloc_entries_per_group(inode) - 1;
-	return (nr >= first) && (nr <= last);
-}
-
-/**
  * nilfs_palloc_freev - deallocate a set of persistent objects
  * @inode: inode of metadata file using this allocator
  * @entry_nrs: array of entry numbers to be deallocated
@@ -708,9 +738,18 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
 	unsigned char *bitmap;
 	void *desc_kaddr, *bitmap_kaddr;
 	unsigned long group, group_offset;
-	int i, j, n, ret;
+	__u64 group_min_nr, last_nrs[8];
+	const unsigned long epg = nilfs_palloc_entries_per_group(inode);
+	const unsigned epb = NILFS_MDT(inode)->mi_entries_per_block;
+	unsigned entry_start, end, pos;
+	spinlock_t *lock;
+	int i, j, k, ret;
+	u32 nfree;
 
 	for (i = 0; i < nitems; i = j) {
+		int change_group = false;
+		int nempties = 0, n = 0;
+
 		group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
 		ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
 		if (ret < 0)
@@ -721,38 +760,89 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
 			brelse(desc_bh);
 			return ret;
 		}
-		desc_kaddr = kmap(desc_bh->b_page);
-		desc = nilfs_palloc_block_get_group_desc(
-			inode, group, desc_bh, desc_kaddr);
+
+		/* Get the first entry number of the group */
+		group_min_nr = (__u64)group * epg;
+
 		bitmap_kaddr = kmap(bitmap_bh->b_page);
 		bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
-		for (j = i, n = 0;
-		     (j < nitems) && nilfs_palloc_group_is_in(inode, group,
-							      entry_nrs[j]);
-		     j++) {
-			nilfs_palloc_group(inode, entry_nrs[j], &group_offset);
-			if (!nilfs_clear_bit_atomic(
-				    nilfs_mdt_bgl_lock(inode, group),
-				    group_offset, bitmap)) {
-				printk(KERN_WARNING
-				       "%s: entry number %llu already freed\n",
-				       __func__,
-				       (unsigned long long)entry_nrs[j]);
+		lock = nilfs_mdt_bgl_lock(inode, group);
+
+		j = i;
+		entry_start = rounddown(group_offset, epb);
+		do {
+			if (!nilfs_clear_bit_atomic(lock, group_offset,
+						    bitmap)) {
+				nilfs_warning(inode->i_sb, __func__,
+					      "entry number %llu already freed: ino=%lu\n",
+					      (unsigned long long)entry_nrs[j],
+					      (unsigned long)inode->i_ino);
 			} else {
 				n++;
 			}
-		}
-		nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
+
+			j++;
+			if (j >= nitems || entry_nrs[j] < group_min_nr ||
+			    entry_nrs[j] >= group_min_nr + epg) {
+				change_group = true;
+			} else {
+				group_offset = entry_nrs[j] - group_min_nr;
+				if (group_offset >= entry_start &&
+				    group_offset < entry_start + epb) {
+					/* This entry is in the same block */
+					continue;
+				}
+			}
+
+			/* Test if the entry block is empty or not */
+			end = entry_start + epb;
+			pos = nilfs_find_next_bit(bitmap, end, entry_start);
+			if (pos >= end) {
+				last_nrs[nempties++] = entry_nrs[j - 1];
+				if (nempties >= ARRAY_SIZE(last_nrs))
+					break;
+			}
+
+			if (change_group)
+				break;
+
+			/* Go on to the next entry block */
+			entry_start = rounddown(group_offset, epb);
+		} while (true);
 
 		kunmap(bitmap_bh->b_page);
-		kunmap(desc_bh->b_page);
+		mark_buffer_dirty(bitmap_bh);
+		brelse(bitmap_bh);
 
+		for (k = 0; k < nempties; k++) {
+			ret = nilfs_palloc_delete_entry_block(inode,
+							      last_nrs[k]);
+			if (ret && ret != -ENOENT) {
+				nilfs_warning(inode->i_sb, __func__,
+					      "failed to delete block of entry %llu: ino=%lu, err=%d\n",
+					      (unsigned long long)last_nrs[k],
+					      (unsigned long)inode->i_ino, ret);
+			}
+		}
+
+		desc_kaddr = kmap_atomic(desc_bh->b_page);
+		desc = nilfs_palloc_block_get_group_desc(
+			inode, group, desc_bh, desc_kaddr);
+		nfree = nilfs_palloc_group_desc_add_entries(desc, lock, n);
+		kunmap_atomic(desc_kaddr);
 		mark_buffer_dirty(desc_bh);
-		mark_buffer_dirty(bitmap_bh);
 		nilfs_mdt_mark_dirty(inode);
-
-		brelse(bitmap_bh);
 		brelse(desc_bh);
+
+		if (nfree == nilfs_palloc_entries_per_group(inode)) {
+			ret = nilfs_palloc_delete_bitmap_block(inode, group);
+			if (ret && ret != -ENOENT) {
+				nilfs_warning(inode->i_sb, __func__,
+					      "failed to delete bitmap block of group %lu: ino=%lu, err=%d\n",
+					      group,
+					      (unsigned long)inode->i_ino, ret);
+			}
+		}
 	}
 	return 0;
 }
diff --git a/kernel/fs/nilfs2/alloc.h b/kernel/fs/nilfs2/alloc.h
index 4bd6451b5..6e6f49aa5 100644
--- a/kernel/fs/nilfs2/alloc.h
+++ b/kernel/fs/nilfs2/alloc.h
@@ -77,6 +77,7 @@ int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
 #define nilfs_set_bit_atomic		ext2_set_bit_atomic
 #define nilfs_clear_bit_atomic		ext2_clear_bit_atomic
 #define nilfs_find_next_zero_bit	find_next_zero_bit_le
+#define nilfs_find_next_bit		find_next_bit_le
 
 /**
  * struct nilfs_bh_assoc - block offset and buffer head association
diff --git a/kernel/fs/nilfs2/btree.c b/kernel/fs/nilfs2/btree.c
index 919fd5bb1..3a3821b00 100644
--- a/kernel/fs/nilfs2/btree.c
+++ b/kernel/fs/nilfs2/btree.c
@@ -919,8 +919,6 @@ static void nilfs_btree_split(struct nilfs_bmap *btree,
 			      int level, __u64 *keyp, __u64 *ptrp)
 {
 	struct nilfs_btree_node *node, *right;
-	__u64 newkey;
-	__u64 newptr;
 	int nchildren, n, move, ncblk;
 
 	node = nilfs_btree_get_nonroot_node(path, level);
@@ -942,9 +940,6 @@ static void nilfs_btree_split(struct nilfs_bmap *btree,
 	if (!buffer_dirty(path[level].bp_sib_bh))
 		mark_buffer_dirty(path[level].bp_sib_bh);
 
-	newkey = nilfs_btree_node_get_key(right, 0);
-	newptr = path[level].bp_newreq.bpr_ptr;
-
 	if (move) {
 		path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 		nilfs_btree_node_insert(right, path[level].bp_index,
@@ -1856,7 +1851,7 @@ int nilfs_btree_convert_and_insert(struct nilfs_bmap *btree,
 				   __u64 key, __u64 ptr,
 				   const __u64 *keys, const __u64 *ptrs, int n)
 {
-	struct buffer_head *bh;
+	struct buffer_head *bh = NULL;
 	union nilfs_bmap_ptr_req dreq, nreq, *di, *ni;
 	struct nilfs_bmap_stats stats;
 	int ret;
diff --git a/kernel/fs/nilfs2/dat.c b/kernel/fs/nilfs2/dat.c
index 0d5fada91..7dc23f100 100644
--- a/kernel/fs/nilfs2/dat.c
+++ b/kernel/fs/nilfs2/dat.c
@@ -155,7 +155,6 @@ void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
 int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
 {
 	struct nilfs_dat_entry *entry;
-	__u64 start;
 	sector_t blocknr;
 	void *kaddr;
 	int ret;
@@ -169,7 +168,6 @@ int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
 	kaddr = kmap_atomic(req->pr_entry_bh->b_page);
 	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
 					     req->pr_entry_bh, kaddr);
-	start = le64_to_cpu(entry->de_start);
 	blocknr = le64_to_cpu(entry->de_blocknr);
 	kunmap_atomic(kaddr);
 
diff --git a/kernel/fs/nilfs2/dir.c b/kernel/fs/nilfs2/dir.c
index 0ee0bed36..6b8b92b19 100644
--- a/kernel/fs/nilfs2/dir.c
+++ b/kernel/fs/nilfs2/dir.c
@@ -61,11 +61,6 @@ static inline void nilfs_put_page(struct page *page)
 	page_cache_release(page);
 }
 
-static inline unsigned long dir_pages(struct inode *inode)
-{
-	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
-}
-
 /*
  * Return the offset into page `page_nr' of the last valid
  * byte in that page, plus one.
diff --git a/kernel/fs/nilfs2/file.c b/kernel/fs/nilfs2/file.c
index 54575e3cc..088ba001c 100644
--- a/kernel/fs/nilfs2/file.c
+++ b/kernel/fs/nilfs2/file.c
@@ -109,7 +109,7 @@ static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 		goto out;
 
 	file_update_time(vma->vm_file);
-	ret = __block_page_mkwrite(vma, vmf, nilfs_get_block);
+	ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 	if (ret) {
 		nilfs_transaction_abort(inode->i_sb);
 		goto out;
diff --git a/kernel/fs/nilfs2/inode.c b/kernel/fs/nilfs2/inode.c
index 258d9fe25..ac2f64943 100644
--- a/kernel/fs/nilfs2/inode.c
+++ b/kernel/fs/nilfs2/inode.c
@@ -307,31 +307,13 @@ static int nilfs_write_end(struct file *file, struct address_space *mapping,
 static ssize_t
 nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 {
-	struct file *file = iocb->ki_filp;
-	struct address_space *mapping = file->f_mapping;
-	struct inode *inode = file->f_mapping->host;
-	size_t count = iov_iter_count(iter);
-	ssize_t size;
+	struct inode *inode = file_inode(iocb->ki_filp);
 
 	if (iov_iter_rw(iter) == WRITE)
 		return 0;
 
 	/* Needs synchronization with the cleaner */
-	size = blockdev_direct_IO(iocb, inode, iter, offset, nilfs_get_block);
-
-	/*
-	 * In case of error extending write may have instantiated a few
-	 * blocks outside i_size. Trim these off again.
-	 */
-	if (unlikely(iov_iter_rw(iter) == WRITE && size < 0)) {
-		loff_t isize = i_size_read(inode);
-		loff_t end = offset + count;
-
-		if (end > isize)
-			nilfs_write_failed(mapping, end);
-	}
-
-	return size;
+	return blockdev_direct_IO(iocb, inode, iter, offset, nilfs_get_block);
 }
 
 const struct address_space_operations nilfs_aops = {
@@ -374,7 +356,7 @@ struct inode *nilfs_new_inode(struct inode *dir, umode_t mode)
 		goto failed;
 
 	mapping_set_gfp_mask(inode->i_mapping,
-			     mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
+			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
 
 	root = NILFS_I(dir)->i_root;
 	ii = NILFS_I(inode);
@@ -540,7 +522,7 @@ static int __nilfs_read_inode(struct super_block *sb,
 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
 	nilfs_set_inode_flags(inode);
 	mapping_set_gfp_mask(inode->i_mapping,
-			     mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
+			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
 	return 0;
 
  failed_unmap:
diff --git a/kernel/fs/nilfs2/ioctl.c b/kernel/fs/nilfs2/ioctl.c
index 9a20e513d..aba43811d 100644
--- a/kernel/fs/nilfs2/ioctl.c
+++ b/kernel/fs/nilfs2/ioctl.c
@@ -1369,7 +1369,6 @@ long nilfs_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	case NILFS_IOCTL_SYNC:
 	case NILFS_IOCTL_RESIZE:
 	case NILFS_IOCTL_SET_ALLOC_RANGE:
-	case FITRIM:
 		break;
 	default:
 		return -ENOIOCTLCMD;
diff --git a/kernel/fs/nilfs2/mdt.c b/kernel/fs/nilfs2/mdt.c
index dee34d990..1125f4023 100644
--- a/kernel/fs/nilfs2/mdt.c
+++ b/kernel/fs/nilfs2/mdt.c
@@ -33,6 +33,7 @@
 #include "page.h"
 #include "mdt.h"
 
+#include <trace/events/nilfs2.h>
 
 #define NILFS_MDT_MAX_RA_BLOCKS		(16 - 1)
 
@@ -68,6 +69,9 @@ nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
 	set_buffer_uptodate(bh);
 	mark_buffer_dirty(bh);
 	nilfs_mdt_mark_dirty(inode);
+
+	trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
+
 	return 0;
 }
 
@@ -158,6 +162,8 @@ nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
 	get_bh(bh);
 	submit_bh(mode, bh);
 	ret = 0;
+
+	trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
  out:
 	get_bh(bh);
 	*out_bh = bh;
diff --git a/kernel/fs/nilfs2/mdt.h b/kernel/fs/nilfs2/mdt.h
index fe529a87a..03246cac3 100644
--- a/kernel/fs/nilfs2/mdt.h
+++ b/kernel/fs/nilfs2/mdt.h
@@ -72,7 +72,7 @@ static inline struct nilfs_mdt_info *NILFS_MDT(const struct inode *inode)
 }
 
 /* Default GFP flags using highmem */
-#define NILFS_MDT_GFP      (__GFP_WAIT | __GFP_IO | __GFP_HIGHMEM)
+#define NILFS_MDT_GFP      (__GFP_RECLAIM | __GFP_IO | __GFP_HIGHMEM)
 
 int nilfs_mdt_get_block(struct inode *, unsigned long, int,
 			void (*init_block)(struct inode *,
diff --git a/kernel/fs/nilfs2/namei.c b/kernel/fs/nilfs2/namei.c
index 22180836e..c9a1a491a 100644
--- a/kernel/fs/nilfs2/namei.c
+++ b/kernel/fs/nilfs2/namei.c
@@ -120,9 +120,6 @@ nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
 	struct nilfs_transaction_info ti;
 	int err;
 
-	if (!new_valid_dev(rdev))
-		return -EINVAL;
-
 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 	if (err)
 		return err;
@@ -496,8 +493,7 @@ static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 {
 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 
-	if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
-	     fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
+	if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
 	    (fh_type != FILEID_NILFS_WITH_PARENT &&
 	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
 		return NULL;
@@ -510,7 +506,7 @@ static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 {
 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 
-	if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
+	if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
 	    fh_type != FILEID_NILFS_WITH_PARENT)
 		return NULL;
 
diff --git a/kernel/fs/nilfs2/recovery.c b/kernel/fs/nilfs2/recovery.c
index ff00a0b7a..9b4f205d1 100644
--- a/kernel/fs/nilfs2/recovery.c
+++ b/kernel/fs/nilfs2/recovery.c
@@ -582,7 +582,7 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
 				 struct nilfs_recovery_info *ri)
 {
 	struct buffer_head *bh_sum = NULL;
-	struct nilfs_segment_summary *sum;
+	struct nilfs_segment_summary *sum = NULL;
 	sector_t pseg_start;
 	sector_t seg_start, seg_end;  /* Starting/ending DBN of full segment */
 	unsigned long nsalvaged_blocks = 0;
@@ -814,7 +814,7 @@ int nilfs_search_super_root(struct the_nilfs *nilfs,
 			    struct nilfs_recovery_info *ri)
 {
 	struct buffer_head *bh_sum = NULL;
-	struct nilfs_segment_summary *sum;
+	struct nilfs_segment_summary *sum = NULL;
 	sector_t pseg_start, pseg_end, sr_pseg_start = 0;
 	sector_t seg_start, seg_end; /* range of full segment (block number) */
 	sector_t b, end;
diff --git a/kernel/fs/nilfs2/segbuf.c b/kernel/fs/nilfs2/segbuf.c
index dc3a9efda..f63620ce3 100644
--- a/kernel/fs/nilfs2/segbuf.c
+++ b/kernel/fs/nilfs2/segbuf.c
@@ -338,17 +338,11 @@ void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
 /*
  * BIO operations
  */
-static void nilfs_end_bio_write(struct bio *bio, int err)
+static void nilfs_end_bio_write(struct bio *bio)
 {
-	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 	struct nilfs_segment_buffer *segbuf = bio->bi_private;
 
-	if (err == -EOPNOTSUPP) {
-		set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
-		/* to be detected by nilfs_segbuf_submit_bio() */
-	}
-
-	if (!uptodate)
+	if (bio->bi_error)
 		atomic_inc(&segbuf->sb_err);
 
 	bio_put(bio);
@@ -374,15 +368,8 @@ static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
 
 	bio->bi_end_io = nilfs_end_bio_write;
 	bio->bi_private = segbuf;
-	bio_get(bio);
 	submit_bio(mode, bio);
 	segbuf->sb_nbio++;
-	if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
-		bio_put(bio);
-		err = -EOPNOTSUPP;
-		goto failed;
-	}
-	bio_put(bio);
 
 	wi->bio = NULL;
 	wi->rest_blocks -= wi->end - wi->start;
@@ -427,7 +414,7 @@ static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 {
 	wi->bio = NULL;
 	wi->rest_blocks = segbuf->sb_sum.nblocks;
-	wi->max_pages = bio_get_nr_vecs(wi->nilfs->ns_bdev);
+	wi->max_pages = BIO_MAX_PAGES;
 	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 	wi->start = wi->end = 0;
 	wi->blocknr = segbuf->sb_pseg_start;
diff --git a/kernel/fs/nilfs2/segment.c b/kernel/fs/nilfs2/segment.c
index c6abbad9b..3b65adaae 100644
--- a/kernel/fs/nilfs2/segment.c
+++ b/kernel/fs/nilfs2/segment.c
@@ -77,6 +77,36 @@ enum {
 	NILFS_ST_DONE,
 };
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/nilfs2.h>
+
+/*
+ * nilfs_sc_cstage_inc(), nilfs_sc_cstage_set(), nilfs_sc_cstage_get() are
+ * wrapper functions of stage count (nilfs_sc_info->sc_stage.scnt). Users of
+ * the variable must use them because transition of stage count must involve
+ * trace events (trace_nilfs2_collection_stage_transition).
+ *
+ * nilfs_sc_cstage_get() isn't required for the above purpose because it doesn't
+ * produce tracepoint events. It is provided just for making the intention
+ * clear.
+ */
+static inline void nilfs_sc_cstage_inc(struct nilfs_sc_info *sci)
+{
+	sci->sc_stage.scnt++;
+	trace_nilfs2_collection_stage_transition(sci);
+}
+
+static inline void nilfs_sc_cstage_set(struct nilfs_sc_info *sci, int next_scnt)
+{
+	sci->sc_stage.scnt = next_scnt;
+	trace_nilfs2_collection_stage_transition(sci);
+}
+
+static inline int nilfs_sc_cstage_get(struct nilfs_sc_info *sci)
+{
+	return sci->sc_stage.scnt;
+}
+
 /* State flags of collection */
 #define NILFS_CF_NODE		0x0001	/* Collecting node blocks */
 #define NILFS_CF_IFILE_STARTED	0x0002	/* IFILE stage has started */
@@ -184,11 +214,18 @@ int nilfs_transaction_begin(struct super_block *sb,
 {
 	struct the_nilfs *nilfs;
 	int ret = nilfs_prepare_segment_lock(ti);
+	struct nilfs_transaction_info *trace_ti;
 
 	if (unlikely(ret < 0))
 		return ret;
-	if (ret > 0)
+	if (ret > 0) {
+		trace_ti = current->journal_info;
+
+		trace_nilfs2_transaction_transition(sb, trace_ti,
+				    trace_ti->ti_count, trace_ti->ti_flags,
+				    TRACE_NILFS2_TRANSACTION_BEGIN);
 		return 0;
+	}
 
 	sb_start_intwrite(sb);
 
@@ -199,6 +236,11 @@ int nilfs_transaction_begin(struct super_block *sb,
 		ret = -ENOSPC;
 		goto failed;
 	}
+
+	trace_ti = current->journal_info;
+	trace_nilfs2_transaction_transition(sb, trace_ti, trace_ti->ti_count,
+					    trace_ti->ti_flags,
+					    TRACE_NILFS2_TRANSACTION_BEGIN);
 	return 0;
 
  failed:
@@ -231,6 +273,8 @@ int nilfs_transaction_commit(struct super_block *sb)
 	ti->ti_flags |= NILFS_TI_COMMIT;
 	if (ti->ti_count > 0) {
 		ti->ti_count--;
+		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
 		return 0;
 	}
 	if (nilfs->ns_writer) {
@@ -242,6 +286,9 @@ int nilfs_transaction_commit(struct super_block *sb)
 			nilfs_segctor_do_flush(sci, 0);
 	}
 	up_read(&nilfs->ns_segctor_sem);
+	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
+
 	current->journal_info = ti->ti_save;
 
 	if (ti->ti_flags & NILFS_TI_SYNC)
@@ -260,10 +307,15 @@ void nilfs_transaction_abort(struct super_block *sb)
 	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 	if (ti->ti_count > 0) {
 		ti->ti_count--;
+		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
 		return;
 	}
 	up_read(&nilfs->ns_segctor_sem);
 
+	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+		    ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
+
 	current->journal_info = ti->ti_save;
 	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
 		kmem_cache_free(nilfs_transaction_cachep, ti);
@@ -309,6 +361,9 @@ static void nilfs_transaction_lock(struct super_block *sb,
 	current->journal_info = ti;
 
 	for (;;) {
+		trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_TRYLOCK);
+
 		down_write(&nilfs->ns_segctor_sem);
 		if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
 			break;
@@ -320,6 +375,9 @@ static void nilfs_transaction_lock(struct super_block *sb,
 	}
 	if (gcflag)
 		ti->ti_flags |= NILFS_TI_GC;
+
+	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_LOCK);
 }
 
 static void nilfs_transaction_unlock(struct super_block *sb)
@@ -332,6 +390,9 @@ static void nilfs_transaction_unlock(struct super_block *sb)
 
 	up_write(&nilfs->ns_segctor_sem);
 	current->journal_info = ti->ti_save;
+
+	trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+			    ti->ti_flags, TRACE_NILFS2_TRANSACTION_UNLOCK);
 }
 
 static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,
@@ -1062,7 +1123,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 	size_t ndone;
 	int err = 0;
 
-	switch (sci->sc_stage.scnt) {
+	switch (nilfs_sc_cstage_get(sci)) {
 	case NILFS_ST_INIT:
 		/* Pre-processes */
 		sci->sc_stage.flags = 0;
@@ -1071,7 +1132,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 			sci->sc_nblk_inc = 0;
 			sci->sc_curseg->sb_sum.flags = NILFS_SS_LOGBGN;
 			if (mode == SC_LSEG_DSYNC) {
-				sci->sc_stage.scnt = NILFS_ST_DSYNC;
+				nilfs_sc_cstage_set(sci, NILFS_ST_DSYNC);
 				goto dsync_mode;
 			}
 		}
@@ -1079,10 +1140,10 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 		sci->sc_stage.dirty_file_ptr = NULL;
 		sci->sc_stage.gc_inode_ptr = NULL;
 		if (mode == SC_FLUSH_DAT) {
-			sci->sc_stage.scnt = NILFS_ST_DAT;
+			nilfs_sc_cstage_set(sci, NILFS_ST_DAT);
 			goto dat_stage;
 		}
-		sci->sc_stage.scnt++;  /* Fall through */
+		nilfs_sc_cstage_inc(sci);  /* Fall through */
 	case NILFS_ST_GC:
 		if (nilfs_doing_gc()) {
 			head = &sci->sc_gc_inodes;
@@ -1103,7 +1164,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 			}
 			sci->sc_stage.gc_inode_ptr = NULL;
 		}
-		sci->sc_stage.scnt++;  /* Fall through */
+		nilfs_sc_cstage_inc(sci);  /* Fall through */
 	case NILFS_ST_FILE:
 		head = &sci->sc_dirty_files;
 		ii = list_prepare_entry(sci->sc_stage.dirty_file_ptr, head,
@@ -1125,10 +1186,10 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 		}
 		sci->sc_stage.dirty_file_ptr = NULL;
 		if (mode == SC_FLUSH_FILE) {
-			sci->sc_stage.scnt = NILFS_ST_DONE;
+			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
 			return 0;
 		}
-		sci->sc_stage.scnt++;
+		nilfs_sc_cstage_inc(sci);
 		sci->sc_stage.flags |= NILFS_CF_IFILE_STARTED;
 		/* Fall through */
 	case NILFS_ST_IFILE:
@@ -1136,7 +1197,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 					      &nilfs_sc_file_ops);
 		if (unlikely(err))
 			break;
-		sci->sc_stage.scnt++;
+		nilfs_sc_cstage_inc(sci);
 		/* Creating a checkpoint */
 		err = nilfs_segctor_create_checkpoint(sci);
 		if (unlikely(err))
@@ -1147,7 +1208,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 					      &nilfs_sc_file_ops);
 		if (unlikely(err))
 			break;
-		sci->sc_stage.scnt++;  /* Fall through */
+		nilfs_sc_cstage_inc(sci);  /* Fall through */
 	case NILFS_ST_SUFILE:
 		err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
 					 sci->sc_nfreesegs, &ndone);
@@ -1163,7 +1224,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 					      &nilfs_sc_file_ops);
 		if (unlikely(err))
 			break;
-		sci->sc_stage.scnt++;  /* Fall through */
+		nilfs_sc_cstage_inc(sci);  /* Fall through */
 	case NILFS_ST_DAT:
  dat_stage:
 		err = nilfs_segctor_scan_file(sci, nilfs->ns_dat,
@@ -1171,10 +1232,10 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 		if (unlikely(err))
 			break;
 		if (mode == SC_FLUSH_DAT) {
-			sci->sc_stage.scnt = NILFS_ST_DONE;
+			nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
 			return 0;
 		}
-		sci->sc_stage.scnt++;  /* Fall through */
+		nilfs_sc_cstage_inc(sci);  /* Fall through */
 	case NILFS_ST_SR:
 		if (mode == SC_LSEG_SR) {
 			/* Appending a super root */
@@ -1184,7 +1245,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 		}
 		/* End of a logical segment */
 		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
-		sci->sc_stage.scnt = NILFS_ST_DONE;
+		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
 		return 0;
 	case NILFS_ST_DSYNC:
  dsync_mode:
@@ -1197,7 +1258,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 		if (unlikely(err))
 			break;
 		sci->sc_curseg->sb_sum.flags |= NILFS_SS_LOGEND;
-		sci->sc_stage.scnt = NILFS_ST_DONE;
+		nilfs_sc_cstage_set(sci, NILFS_ST_DONE);
 		return 0;
 	case NILFS_ST_DONE:
 		return 0;
@@ -1442,7 +1503,8 @@ static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
 			goto failed;
 
 		/* The current segment is filled up */
-		if (mode != SC_LSEG_SR || sci->sc_stage.scnt < NILFS_ST_CPFILE)
+		if (mode != SC_LSEG_SR ||
+		    nilfs_sc_cstage_get(sci) < NILFS_ST_CPFILE)
 			break;
 
 		nilfs_clear_logs(&sci->sc_segbufs);
@@ -1946,7 +2008,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	int err;
 
-	sci->sc_stage.scnt = NILFS_ST_INIT;
+	nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
 	sci->sc_cno = nilfs->ns_cno;
 
 	err = nilfs_segctor_collect_dirty_files(sci, nilfs);
@@ -1974,7 +2036,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 			goto failed;
 
 		/* Avoid empty segment */
-		if (sci->sc_stage.scnt == NILFS_ST_DONE &&
+		if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE &&
 		    nilfs_segbuf_empty(sci->sc_curseg)) {
 			nilfs_segctor_abort_construction(sci, nilfs, 1);
 			goto out;
@@ -1988,7 +2050,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 			nilfs_segctor_fill_in_file_bmap(sci);
 
 		if (mode == SC_LSEG_SR &&
-		    sci->sc_stage.scnt >= NILFS_ST_CPFILE) {
+		    nilfs_sc_cstage_get(sci) >= NILFS_ST_CPFILE) {
 			err = nilfs_segctor_fill_in_checkpoint(sci);
 			if (unlikely(err))
 				goto failed_to_write;
@@ -2007,7 +2069,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 		if (unlikely(err))
 			goto failed_to_write;
 
-		if (sci->sc_stage.scnt == NILFS_ST_DONE ||
+		if (nilfs_sc_cstage_get(sci) == NILFS_ST_DONE ||
 		    nilfs->ns_blocksize_bits != PAGE_CACHE_SHIFT) {
 			/*
 			 * At this point, we avoid double buffering
@@ -2020,7 +2082,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 			if (err)
 				goto failed_to_write;
 		}
-	} while (sci->sc_stage.scnt != NILFS_ST_DONE);
+	} while (nilfs_sc_cstage_get(sci) != NILFS_ST_DONE);
 
  out:
 	nilfs_segctor_drop_written_files(sci, nilfs);
@@ -2430,7 +2492,6 @@ static void nilfs_segctor_thread_construct(struct nilfs_sc_info *sci, int mode)
 static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
 {
 	int mode = 0;
-	int err;
 
 	spin_lock(&sci->sc_state_lock);
 	mode = (sci->sc_flush_request & FLUSH_DAT_BIT) ?
@@ -2438,7 +2499,7 @@ static void nilfs_segctor_do_immediate_flush(struct nilfs_sc_info *sci)
 	spin_unlock(&sci->sc_state_lock);
 
 	if (mode) {
-		err = nilfs_segctor_do_construct(sci, mode);
+		nilfs_segctor_do_construct(sci, mode);
 
 		spin_lock(&sci->sc_state_lock);
 		sci->sc_flush_request &= (mode == SC_FLUSH_FILE) ?
diff --git a/kernel/fs/nilfs2/segment.h b/kernel/fs/nilfs2/segment.h
index a48d6de1e..0408b9b28 100644
--- a/kernel/fs/nilfs2/segment.h
+++ b/kernel/fs/nilfs2/segment.h
@@ -67,7 +67,8 @@ struct nilfs_recovery_info {
 
 /**
  * struct nilfs_cstage - Context of collection stage
- * @scnt: Stage count
+ * @scnt: Stage count, must be accessed via wrappers:
+ *        nilfs_sc_cstage_inc(), nilfs_sc_cstage_set(), nilfs_sc_cstage_get()
  * @flags: State flags
  * @dirty_file_ptr: Pointer on dirty_files list, or inode of a target file
  * @gc_inode_ptr: Pointer on the list of gc-inodes
diff --git a/kernel/fs/nilfs2/sufile.c b/kernel/fs/nilfs2/sufile.c
index 2a869c35c..52821ffc1 100644
--- a/kernel/fs/nilfs2/sufile.c
+++ b/kernel/fs/nilfs2/sufile.c
@@ -30,6 +30,8 @@
 #include "mdt.h"
 #include "sufile.h"
 
+#include <trace/events/nilfs2.h>
+
 /**
  * struct nilfs_sufile_info - on-memory private data of sufile
  * @mi: on-memory private data of metadata file
@@ -317,7 +319,7 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 	size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 	__u64 segnum, maxsegnum, last_alloc;
 	void *kaddr;
-	unsigned long nsegments, ncleansegs, nsus, cnt;
+	unsigned long nsegments, nsus, cnt;
 	int ret, j;
 
 	down_write(&NILFS_MDT(sufile)->mi_sem);
@@ -327,7 +329,6 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 		goto out_sem;
 	kaddr = kmap_atomic(header_bh->b_page);
 	header = kaddr + bh_offset(header_bh);
-	ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 	last_alloc = le64_to_cpu(header->sh_last_alloc);
 	kunmap_atomic(kaddr);
 
@@ -358,6 +359,7 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 				break; /* never happens */
 			}
 		}
+		trace_nilfs2_segment_usage_check(sufile, segnum, cnt);
 		ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
 							   &su_bh);
 		if (ret < 0)
@@ -388,6 +390,9 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 			nilfs_mdt_mark_dirty(sufile);
 			brelse(su_bh);
 			*segnump = segnum;
+
+			trace_nilfs2_segment_usage_allocated(sufile, segnum);
+
 			goto out_header;
 		}
 
@@ -490,6 +495,8 @@ void nilfs_sufile_do_free(struct inode *sufile, __u64 segnum,
 	NILFS_SUI(sufile)->ncleansegs++;
 
 	nilfs_mdt_mark_dirty(sufile);
+
+	trace_nilfs2_segment_usage_freed(sufile, segnum);
 }
 
 /**
diff --git a/kernel/fs/nilfs2/super.c b/kernel/fs/nilfs2/super.c
index f47585bfe..354013ea2 100644
--- a/kernel/fs/nilfs2/super.c
+++ b/kernel/fs/nilfs2/super.c
@@ -361,7 +361,7 @@ static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 	struct nilfs_super_block *nsbp;
 	sector_t blocknr, newblocknr;
 	unsigned long offset;
-	int sb2i = -1;  /* array index of the secondary superblock */
+	int sb2i;  /* array index of the secondary superblock */
 	int ret = 0;
 
 	/* nilfs->ns_sem must be locked by the caller. */
@@ -372,6 +372,9 @@ static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 	} else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 		sb2i = 0;
 		blocknr = nilfs->ns_sbh[0]->b_blocknr;
+	} else {
+		sb2i = -1;
+		blocknr = 0;
 	}
 	if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 		goto out;  /* super block location is unchanged */
@@ -1405,14 +1408,10 @@ static void nilfs_destroy_cachep(void)
 	 */
 	rcu_barrier();
 
-	if (nilfs_inode_cachep)
-		kmem_cache_destroy(nilfs_inode_cachep);
-	if (nilfs_transaction_cachep)
-		kmem_cache_destroy(nilfs_transaction_cachep);
-	if (nilfs_segbuf_cachep)
-		kmem_cache_destroy(nilfs_segbuf_cachep);
-	if (nilfs_btree_path_cache)
-		kmem_cache_destroy(nilfs_btree_path_cache);
+	kmem_cache_destroy(nilfs_inode_cachep);
+	kmem_cache_destroy(nilfs_transaction_cachep);
+	kmem_cache_destroy(nilfs_segbuf_cachep);
+	kmem_cache_destroy(nilfs_btree_path_cache);
 }
 
 static int __init nilfs_init_cachep(void)