--- zzzz-none-000/linux-3.10.107/fs/nilfs2/alloc.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/nilfs2/alloc.c	2021-02-04 17:41:59.000000000 +0000
@@ -133,38 +133,38 @@
 
 /**
  * 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 @@
 }
 
 /**
+ * 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 @@
 }
 
 /**
+ * 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 @@
 }
 
 /**
+ * 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 @@
 
 /**
  * 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)
+					    unsigned bsize,
+					    spinlock_t *lock)
 {
-	int curr, pos, end, i;
+	int pos, end = bsize;
 
-	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))
+	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;
 }
 
@@ -398,6 +437,70 @@
 }
 
 /**
+ * nilfs_palloc_count_desc_blocks - count descriptor blocks number
+ * @inode: inode of metadata file using this allocator
+ * @desc_blocks: descriptor blocks number [out]
+ */
+static int nilfs_palloc_count_desc_blocks(struct inode *inode,
+					    unsigned long *desc_blocks)
+{
+	__u64 blknum;
+	int ret;
+
+	ret = nilfs_bmap_last_key(NILFS_I(inode)->i_bmap, &blknum);
+	if (likely(!ret))
+		*desc_blocks = DIV_ROUND_UP(
+			(unsigned long)blknum,
+			NILFS_MDT(inode)->mi_blocks_per_desc_block);
+	return ret;
+}
+
+/**
+ * nilfs_palloc_mdt_file_can_grow - check potential opportunity for
+ *					MDT file growing
+ * @inode: inode of metadata file using this allocator
+ * @desc_blocks: known current descriptor blocks count
+ */
+static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,
+						    unsigned long desc_blocks)
+{
+	return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <
+			nilfs_palloc_groups_count(inode);
+}
+
+/**
+ * nilfs_palloc_count_max_entries - count max number of entries that can be
+ *					described by descriptor blocks count
+ * @inode: inode of metadata file using this allocator
+ * @nused: current number of used entries
+ * @nmaxp: max number of entries [out]
+ */
+int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
+{
+	unsigned long desc_blocks = 0;
+	u64 entries_per_desc_block, nmax;
+	int err;
+
+	err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);
+	if (unlikely(err))
+		return err;
+
+	entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *
+				nilfs_palloc_groups_per_desc_block(inode);
+	nmax = entries_per_desc_block * desc_blocks;
+
+	if (nused == nmax &&
+			nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))
+		nmax += entries_per_desc_block;
+
+	if (nused > nmax)
+		return -ERANGE;
+
+	*nmaxp = nmax;
+	return 0;
+}
+
+/**
  * nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
  * @inode: inode of metadata file using this allocator
  * @req: nilfs_palloc_req structure exchanged for the allocation
@@ -411,15 +514,15 @@
 	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) {
@@ -437,8 +540,8 @@
 		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)
@@ -446,12 +549,12 @@
 				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);
@@ -509,6 +612,7 @@
 	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);
@@ -516,13 +620,15 @@
 						 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);
@@ -547,6 +653,7 @@
 	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);
@@ -554,12 +661,15 @@
 						 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);
@@ -616,22 +726,6 @@
 }
 
 /**
- * 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
@@ -644,9 +738,18 @@
 	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)
@@ -657,38 +760,89 @@
 			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;
 }