nilfs2: replace BUG_ON and BUG calls triggerable from ioctl

Pekka Enberg advised me:
> It would be nice if BUG(), BUG_ON(), and panic() calls would be
> converted to proper error handling using WARN_ON() calls. The BUG()
> call in nilfs_cpfile_delete_checkpoints(), for example, looks to be
> triggerable from user-space via the ioctl() system call.

This will follow the comment and keep them to a minimum.

Acked-by: Pekka Enberg <[email protected]>
Signed-off-by: Ryusuke Konishi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

fs/nilfs2/btree.c

@@ -425,7 +425,6 @@ static int nilfs_btree_node_lookup(const struct nilfs_btree *btree,
 		index++;
 
  out:
-	BUG_ON(indexp == NULL);
 	*indexp = index;
 
 	return s == 0;
@@ -477,8 +476,6 @@ static int nilfs_btree_do_lookup(const struct nilfs_btree *btree,
 	__u64 ptr;
 	int level, index, found, ret;
 
-	BUG_ON(minlevel <= NILFS_BTREE_LEVEL_DATA);
-
 	node = nilfs_btree_get_root(btree);
 	level = nilfs_btree_node_get_level(btree, node);
 	if ((level < minlevel) ||
@@ -505,7 +502,7 @@ static int nilfs_btree_do_lookup(const struct nilfs_btree *btree,
 		if (index < nilfs_btree_node_nchildren_max(btree, node))
 			ptr = nilfs_btree_node_get_ptr(btree, node, index);
 		else {
-			BUG_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
+			WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
 			/* insert */
 			ptr = NILFS_BMAP_INVALID_PTR;
 		}
@@ -1366,7 +1363,7 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
 		} else {
 			/* no siblings */
 			/* the only child of the root node */
-			BUG_ON(level != nilfs_btree_height(btree) - 2);
+			WARN_ON(level != nilfs_btree_height(btree) - 2);
 			if (nilfs_btree_node_get_nchildren(btree, node) - 1 <=
 			    NILFS_BTREE_ROOT_NCHILDREN_MAX) {
 				path[level].bp_op = nilfs_btree_shrink;
@@ -1543,7 +1540,7 @@ static int nilfs_btree_gather_data(struct nilfs_bmap *bmap,
 		break;
 	case 3:
 		nchildren = nilfs_btree_node_get_nchildren(btree, root);
-		BUG_ON(nchildren > 1);
+		WARN_ON(nchildren > 1);
 		ptr = nilfs_btree_node_get_ptr(btree, root, nchildren - 1);
 		ret = nilfs_bmap_get_block(bmap, ptr, &bh);
 		if (ret < 0)
@@ -1552,7 +1549,7 @@ static int nilfs_btree_gather_data(struct nilfs_bmap *bmap,
 		break;
 	default:
 		node = NULL;
-		BUG();
+		return -EINVAL;
 	}
 
 	nchildren = nilfs_btree_node_get_nchildren(btree, node);
@@ -1833,14 +1830,13 @@ static int nilfs_btree_prepare_propagate_v(struct nilfs_btree *btree,
 	while ((++level < nilfs_btree_height(btree) - 1) &&
 	       !buffer_dirty(path[level].bp_bh)) {
 
-		BUG_ON(buffer_nilfs_volatile(path[level].bp_bh));
+		WARN_ON(buffer_nilfs_volatile(path[level].bp_bh));
 		ret = nilfs_btree_prepare_update_v(btree, path, level);
 		if (ret < 0)
 			goto out;
 	}
 
 	/* success */
-	BUG_ON(maxlevelp == NULL);
 	*maxlevelp = level - 1;
 	return 0;
 
@@ -1909,7 +1905,7 @@ static int nilfs_btree_propagate(const struct nilfs_bmap *bmap,
 	__u64 key;
 	int level, ret;
 
-	BUG_ON(!buffer_dirty(bh));
+	WARN_ON(!buffer_dirty(bh));
 
 	btree = (struct nilfs_btree *)bmap;
 	path = nilfs_btree_alloc_path(btree);
@@ -1928,12 +1924,9 @@ static int nilfs_btree_propagate(const struct nilfs_bmap *bmap,
 
 	ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1);
 	if (ret < 0) {
-		/* BUG_ON(ret == -ENOENT); */
-		if (ret == -ENOENT) {
+		if (unlikely(ret == -ENOENT))
 			printk(KERN_CRIT "%s: key = %llu, level == %d\n",
 			       __func__, (unsigned long long)key, level);
-			BUG();
-		}
 		goto out;
 	}
 
@@ -2117,7 +2110,7 @@ static int nilfs_btree_assign(struct nilfs_bmap *bmap,
 
 	ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1);
 	if (ret < 0) {
-		BUG_ON(ret == -ENOENT);
+		WARN_ON(ret == -ENOENT);
 		goto out;
 	}
 
@@ -2175,12 +2168,12 @@ static int nilfs_btree_mark(struct nilfs_bmap *bmap, __u64 key, int level)
 
 	ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1);
 	if (ret < 0) {
-		BUG_ON(ret == -ENOENT);
+		WARN_ON(ret == -ENOENT);
 		goto out;
 	}
 	ret = nilfs_bmap_get_block(&btree->bt_bmap, ptr, &bh);
 	if (ret < 0) {
-		BUG_ON(ret == -ENOENT);
+		WARN_ON(ret == -ENOENT);
 		goto out;
 	}
 

fs/nilfs2/cpfile.c

@@ -40,10 +40,7 @@ nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
 static unsigned long
 nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
 {
-	__u64 tcno;
-
-	BUG_ON(cno == 0); /* checkpoint number 0 is invalid */
-	tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
+	__u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
 	do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
 	return (unsigned long)tcno;
 }
@@ -96,7 +93,7 @@ nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
 	struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
 	unsigned int count;
 
-	BUG_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
+	WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
 	count = le32_to_cpu(cp->cp_checkpoints_count) - n;
 	cp->cp_checkpoints_count = cpu_to_le32(count);
 	return count;
@@ -178,6 +175,8 @@ static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
  * %-ENOMEM - Insufficient amount of memory available.
  *
  * %-ENOENT - No such checkpoint.
+ *
+ * %-EINVAL - invalid checkpoint.
  */
 int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
 				__u64 cno,
@@ -191,8 +190,9 @@ int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
 	void *kaddr;
 	int ret;
 
-	BUG_ON(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
-	       (cno < nilfs_mdt_cno(cpfile) && create));
+	if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
+		     (cno < nilfs_mdt_cno(cpfile) && create)))
+		return -EINVAL;
 
 	down_write(&NILFS_MDT(cpfile)->mi_sem);
 
@@ -288,12 +288,11 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
 	unsigned long tnicps;
 	int ret, ncps, nicps, count, i;
 
-	if ((start == 0) || (start > end)) {
-		printk(KERN_CRIT "%s: start = %llu, end = %llu\n",
-		       __func__,
-		       (unsigned long long)start,
-		       (unsigned long long)end);
-		BUG();
+	if (unlikely(start == 0 || start > end)) {
+		printk(KERN_ERR "%s: invalid range of checkpoint numbers: "
+		       "[%llu, %llu)\n", __func__,
+		       (unsigned long long)start, (unsigned long long)end);
+		return -EINVAL;
 	}
 
 	/* cannot delete the latest checkpoint */
@@ -323,7 +322,7 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
 			cpfile, cno, cp_bh, kaddr);
 		nicps = 0;
 		for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
-			BUG_ON(nilfs_checkpoint_snapshot(cp));
+			WARN_ON(nilfs_checkpoint_snapshot(cp));
 			if (!nilfs_checkpoint_invalid(cp)) {
 				nilfs_checkpoint_set_invalid(cp);
 				nicps++;
@@ -393,6 +392,8 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
 	int n, ret;
 	int ncps, i;
 
+	if (cno == 0)
+		return -ENOENT; /* checkpoint number 0 is invalid */
 	down_read(&NILFS_MDT(cpfile)->mi_sem);
 
 	for (n = 0; cno < cur_cno && n < nci; cno += ncps) {
@@ -532,9 +533,6 @@ int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
 	ssize_t nci;
 	int ret;
 
-	/* checkpoint number 0 is invalid */
-	if (cno == 0)
-		return -ENOENT;
 	nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1);
 	if (nci < 0)
 		return nci;
@@ -582,6 +580,8 @@ static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
 	void *kaddr;
 	int ret;
 
+	if (cno == 0)
+		return -ENOENT; /* checkpoint number 0 is invalid */
 	down_write(&NILFS_MDT(cpfile)->mi_sem);
 
 	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
@@ -698,6 +698,8 @@ static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
 	void *kaddr;
 	int ret;
 
+	if (cno == 0)
+		return -ENOENT; /* checkpoint number 0 is invalid */
 	down_write(&NILFS_MDT(cpfile)->mi_sem);
 
 	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
@@ -813,6 +815,8 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
 	void *kaddr;
 	int ret;
 
+	if (cno == 0)
+		return -ENOENT; /* checkpoint number 0 is invalid */
 	down_read(&NILFS_MDT(cpfile)->mi_sem);
 
 	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);

fs/nilfs2/dat.c

@@ -135,7 +135,7 @@ int nilfs_dat_prepare_start(struct inode *dat, struct nilfs_palloc_req *req)
 	int ret;
 
 	ret = nilfs_dat_prepare_entry(dat, req, 0);
-	BUG_ON(ret == -ENOENT);
+	WARN_ON(ret == -ENOENT);
 	return ret;
 }
 
@@ -157,7 +157,6 @@ void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
 		       (unsigned long long)le64_to_cpu(entry->de_start),
 		       (unsigned long long)le64_to_cpu(entry->de_end),
 		       (unsigned long long)le64_to_cpu(entry->de_blocknr));
-		BUG();
 	}
 	entry->de_blocknr = cpu_to_le64(blocknr);
 	kunmap_atomic(kaddr, KM_USER0);
@@ -180,7 +179,7 @@ int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
 
 	ret = nilfs_dat_prepare_entry(dat, req, 0);
 	if (ret < 0) {
-		BUG_ON(ret == -ENOENT);
+		WARN_ON(ret == -ENOENT);
 		return ret;
 	}
 
@@ -216,7 +215,7 @@ void nilfs_dat_commit_end(struct inode *dat, struct nilfs_palloc_req *req,
 	end = start = le64_to_cpu(entry->de_start);
 	if (!dead) {
 		end = nilfs_mdt_cno(dat);
-		BUG_ON(start > end);
+		WARN_ON(start > end);
 	}
 	entry->de_end = cpu_to_le64(end);
 	blocknr = le64_to_cpu(entry->de_blocknr);
@@ -324,14 +323,16 @@ int nilfs_dat_move(struct inode *dat, __u64 vblocknr, sector_t blocknr)
 		return ret;
 	kaddr = kmap_atomic(entry_bh->b_page, KM_USER0);
 	entry = nilfs_palloc_block_get_entry(dat, vblocknr, entry_bh, kaddr);
-	if (entry->de_blocknr == cpu_to_le64(0)) {
+	if (unlikely(entry->de_blocknr == cpu_to_le64(0))) {
 		printk(KERN_CRIT "%s: vbn = %llu, [%llu, %llu)\n", __func__,
 		       (unsigned long long)vblocknr,
 		       (unsigned long long)le64_to_cpu(entry->de_start),
 		       (unsigned long long)le64_to_cpu(entry->de_end));
-		BUG();
+		kunmap_atomic(kaddr, KM_USER0);
+		brelse(entry_bh);
+		return -EINVAL;
 	}
-	BUG_ON(blocknr == 0);
+	WARN_ON(blocknr == 0);
 	entry->de_blocknr = cpu_to_le64(blocknr);
 	kunmap_atomic(kaddr, KM_USER0);
 

fs/nilfs2/direct.c

@@ -210,7 +210,6 @@ static int nilfs_direct_last_key(const struct nilfs_bmap *bmap, __u64 *keyp)
 	if (lastkey == NILFS_DIRECT_KEY_MAX + 1)
 		return -ENOENT;
 
-	BUG_ON(keyp == NULL);
 	*keyp = lastkey;
 
 	return 0;
@@ -366,9 +365,17 @@ static int nilfs_direct_assign(struct nilfs_bmap *bmap,
 
 	direct = (struct nilfs_direct *)bmap;
 	key = nilfs_bmap_data_get_key(bmap, *bh);
-	BUG_ON(key > NILFS_DIRECT_KEY_MAX);
+	if (unlikely(key > NILFS_DIRECT_KEY_MAX)) {
+		printk(KERN_CRIT "%s: invalid key: %llu\n", __func__,
+		       (unsigned long long)key);
+		return -EINVAL;
+	}
 	ptr = nilfs_direct_get_ptr(direct, key);
-	BUG_ON(ptr == NILFS_BMAP_INVALID_PTR);
+	if (unlikely(ptr == NILFS_BMAP_INVALID_PTR)) {
+		printk(KERN_CRIT "%s: invalid pointer: %llu\n", __func__,
+		       (unsigned long long)ptr);
+		return -EINVAL;
+	}
 
 	return direct->d_ops->dop_assign(direct, key, ptr, bh,
 					 blocknr, binfo);

fs/nilfs2/inode.c

@@ -61,12 +61,6 @@ int nilfs_get_block(struct inode *inode, sector_t blkoff,
 		map_bh(bh_result, inode->i_sb, blknum);
 		goto out;
 	}
-	if (unlikely(ret == 1)) {
-		printk(KERN_ERR "nilfs_get_block: bmap_lookup returns "
-		       "buffer_head pointer (blkoff=%llu, blknum=%lu)\n",
-		       (unsigned long long)blkoff, blknum);
-		BUG();
-	}
 	/* data block was not found */
 	if (ret == -ENOENT && create) {
 		struct nilfs_transaction_info ti;
@@ -85,14 +79,14 @@ int nilfs_get_block(struct inode *inode, sector_t blkoff,
 				 * However, the page having this block must
 				 * be locked in this case.
 				 */
-				printk(KERN_ERR
+				printk(KERN_WARNING
 				       "nilfs_get_block: a race condition "
 				       "while inserting a data block. "
 				       "(inode number=%lu, file block "
 				       "offset=%llu)\n",
 				       inode->i_ino,
 				       (unsigned long long)blkoff);
-				BUG();
+				err = 0;
 			} else if (err == -EINVAL) {
 				nilfs_error(inode->i_sb, __func__,
 					    "broken bmap (inode=%lu)\n",
@@ -621,7 +615,6 @@ void nilfs_truncate(struct inode *inode)
 	struct nilfs_transaction_info ti;
 	struct super_block *sb = inode->i_sb;
 	struct nilfs_inode_info *ii = NILFS_I(inode);
-	int ret;
 
 	if (!test_bit(NILFS_I_BMAP, &ii->i_state))
 		return;
@@ -630,8 +623,7 @@ void nilfs_truncate(struct inode *inode)
 
 	blocksize = sb->s_blocksize;
 	blkoff = (inode->i_size + blocksize - 1) >> sb->s_blocksize_bits;
-	ret = nilfs_transaction_begin(sb, &ti, 0);
-	BUG_ON(ret);
+	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
 
 	block_truncate_page(inode->i_mapping, inode->i_size, nilfs_get_block);
 
@@ -652,16 +644,15 @@ void nilfs_delete_inode(struct inode *inode)
 	struct nilfs_transaction_info ti;
 	struct super_block *sb = inode->i_sb;
 	struct nilfs_inode_info *ii = NILFS_I(inode);
-	int err;
 
 	if (unlikely(is_bad_inode(inode))) {
 		if (inode->i_data.nrpages)
 			truncate_inode_pages(&inode->i_data, 0);
 		clear_inode(inode);
 		return;
 	}
-	err = nilfs_transaction_begin(sb, &ti, 0);
-	BUG_ON(err);
+	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
+
 	if (inode->i_data.nrpages)
 		truncate_inode_pages(&inode->i_data, 0);