Merge tag 'fs_for_v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull ext2, udf, quota updates from Jan Kara:

 - A fix for a race in quota code that can expose ocfs2 to
   use-after-free issues

 - UDF fix to avoid memory corruption in face of corrupted format

 - Couple of ext2 fixes for better handling of fs corruption

 - Some more various code cleanups in UDF & ext2

* tag 'fs_for_v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: reject inodes with zero i_nlink and valid mode in ext2_iget()
  ext2: use get_random_u32() where appropriate
  quota: Fix race of dquot_scan_active() with quota deactivation
  udf: fix partition descriptor append bookkeeping
  ext2: avoid drop_nlink() during unlink of zero-nlink inode in ext2_unlink()
  ext2: guard reservation window dump with EXT2FS_DEBUG
  ext2: replace BUG_ON with WARN_ON_ONCE in ext2_get_blocks
  ext2: remove stale TODO about kmap
  fs: udf: avoid assignment in condition when selecting allocation goal

Author: torvalds

fs/ext2/balloc.c

@@ -201,7 +201,7 @@ static void group_adjust_blocks(struct super_block *sb, int group_no,
  * windows(start, end). Otherwise, it will only print out the "bad" windows,
  * those windows that overlap with their immediate neighbors.
  */
-#if 1
+#ifdef EXT2FS_DEBUG
 static void __rsv_window_dump(struct rb_root *root, int verbose,
 			      const char *fn)
 {
@@ -248,7 +248,7 @@ static void __rsv_window_dump(struct rb_root *root, int verbose,
 	__rsv_window_dump((root), (verbose), __func__)
 #else
 #define rsv_window_dump(root, verbose) do {} while (0)
-#endif
+#endif /* EXT2FS_DEBUG */
 
 /**
  * goal_in_my_reservation()

fs/ext2/inode.c

@@ -639,7 +639,8 @@ static int ext2_get_blocks(struct inode *inode,
 	int count = 0;
 	ext2_fsblk_t first_block = 0;
 
-	BUG_ON(maxblocks == 0);
+	if (WARN_ON_ONCE(maxblocks == 0))
+		return -EINVAL;
 
 	depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
 
@@ -1433,9 +1434,17 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 	 * the test is that same one that e2fsck uses
 	 * NeilBrown 1999oct15
 	 */
-	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
-		/* this inode is deleted */
-		ret = -ESTALE;
+	if (inode->i_nlink == 0) {
+		if (inode->i_mode == 0 || ei->i_dtime) {
+			/* this inode is deleted */
+			ret = -ESTALE;
+		} else {
+			ext2_error(sb, __func__,
+				   "inode %lu has zero i_nlink with mode 0%o and no dtime, "
+				   "filesystem may be corrupt",
+				   ino, inode->i_mode);
+			ret = -EFSCORRUPTED;
+		}
 		goto bad_inode;
 	}
 	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);

fs/ext2/namei.c

@@ -14,8 +14,6 @@
  *
  * The only non-static object here is ext2_dir_inode_operations.
  *
- * TODO: get rid of kmap() use, add readahead.
- *
  * Copyright (C) 1992, 1993, 1994, 1995
  * Remy Card (card@masi.ibp.fr)
  * Laboratoire MASI - Institut Blaise Pascal
@@ -293,7 +291,10 @@ static int ext2_unlink(struct inode *dir, struct dentry *dentry)
 		goto out;
 
 	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
-	inode_dec_link_count(inode);
+
+	if (inode->i_nlink)
+		inode_dec_link_count(inode);
+
 	err = 0;
 out:
 	return err;

fs/ext2/super.c

@@ -1152,7 +1152,7 @@ static int ext2_fill_super(struct super_block *sb, struct fs_context *fc)
 		goto failed_mount2;
 	}
 	sbi->s_gdb_count = db_count;
-	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
+	sbi->s_next_generation = get_random_u32();
 	spin_lock_init(&sbi->s_next_gen_lock);
 
 	/* per filesystem reservation list head & lock */

fs/quota/dquot.c

@@ -363,6 +363,31 @@ static inline int dquot_active(struct dquot *dquot)
 	return test_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 }
 
+static struct dquot *__dqgrab(struct dquot *dquot)
+{
+	lockdep_assert_held(&dq_list_lock);
+	if (!atomic_read(&dquot->dq_count))
+		remove_free_dquot(dquot);
+	atomic_inc(&dquot->dq_count);
+	return dquot;
+}
+
+/*
+ * Get reference to dquot when we got pointer to it by some other means. The
+ * dquot has to be active and the caller has to make sure it cannot get
+ * deactivated under our hands.
+ */
+struct dquot *dqgrab(struct dquot *dquot)
+{
+	spin_lock(&dq_list_lock);
+	WARN_ON_ONCE(!dquot_active(dquot));
+	dquot = __dqgrab(dquot);
+	spin_unlock(&dq_list_lock);
+
+	return dquot;
+}
+EXPORT_SYMBOL_GPL(dqgrab);
+
 static inline int dquot_dirty(struct dquot *dquot)
 {
 	return test_bit(DQ_MOD_B, &dquot->dq_flags);
@@ -641,15 +666,14 @@ int dquot_scan_active(struct super_block *sb,
 			continue;
 		if (dquot->dq_sb != sb)
 			continue;
-		/* Now we have active dquot so we can just increase use count */
-		atomic_inc(&dquot->dq_count);
+		__dqgrab(dquot);
 		spin_unlock(&dq_list_lock);
 		dqput(old_dquot);
 		old_dquot = dquot;
 		/*
 		 * ->release_dquot() can be racing with us. Our reference
-		 * protects us from new calls to it so just wait for any
-		 * outstanding call and recheck the DQ_ACTIVE_B after that.
+		 * protects us from dquot_release() proceeding so just wait for
+		 * any outstanding call and recheck the DQ_ACTIVE_B after that.
 		 */
 		wait_on_dquot(dquot);
 		if (dquot_active(dquot)) {
@@ -717,7 +741,7 @@ int dquot_writeback_dquots(struct super_block *sb, int type)
 			/* Now we have active dquot from which someone is
  			 * holding reference so we can safely just increase
 			 * use count */
-			dqgrab(dquot);
+			__dqgrab(dquot);
 			spin_unlock(&dq_list_lock);
 			err = dquot_write_dquot(dquot);
 			if (err && !ret)
@@ -963,9 +987,7 @@ struct dquot *dqget(struct super_block *sb, struct kqid qid)
 		spin_unlock(&dq_list_lock);
 		dqstats_inc(DQST_LOOKUPS);
 	} else {
-		if (!atomic_read(&dquot->dq_count))
-			remove_free_dquot(dquot);
-		atomic_inc(&dquot->dq_count);
+		__dqgrab(dquot);
 		spin_unlock(&dq_list_lock);
 		dqstats_inc(DQST_CACHE_HITS);
 		dqstats_inc(DQST_LOOKUPS);

fs/udf/inode.c

@@ -733,7 +733,7 @@ static int inode_getblk(struct inode *inode, struct udf_map_rq *map)
 	sector_t offset = 0;
 	int8_t etype, tmpetype;
 	struct udf_inode_info *iinfo = UDF_I(inode);
-	udf_pblk_t goal = 0, pgoal = iinfo->i_location.logicalBlockNum;
+	udf_pblk_t goal = 0, pgoal = 0;
 	int lastblock = 0;
 	bool isBeyondEOF = false;
 	int ret = 0;
@@ -892,11 +892,10 @@ static int inode_getblk(struct inode *inode, struct udf_map_rq *map)
 	else { /* otherwise, allocate a new block */
 		if (iinfo->i_next_alloc_block == map->lblk)
 			goal = iinfo->i_next_alloc_goal;
-
-		if (!goal) {
-			if (!(goal = pgoal)) /* XXX: what was intended here? */
-				goal = iinfo->i_location.logicalBlockNum + 1;
-		}
+		if (!goal)
+			goal = pgoal;
+		if (!goal)
+			goal = iinfo->i_location.logicalBlockNum + 1;
 
 		newblocknum = udf_new_block(inode->i_sb, inode,
 				iinfo->i_location.partitionReferenceNum,

fs/udf/super.c

@@ -1695,8 +1695,9 @@ static struct udf_vds_record *handle_partition_descriptor(
 			return &(data->part_descs_loc[i].rec);
 	if (data->num_part_descs >= data->size_part_descs) {
 		struct part_desc_seq_scan_data *new_loc;
-		unsigned int new_size = ALIGN(partnum, PART_DESC_ALLOC_STEP);
+		unsigned int new_size;
 
+		new_size = data->num_part_descs + PART_DESC_ALLOC_STEP;
 		new_loc = kzalloc_objs(*new_loc, new_size);
 		if (!new_loc)
 			return ERR_PTR(-ENOMEM);
@@ -1706,6 +1707,7 @@ static struct udf_vds_record *handle_partition_descriptor(
 		data->part_descs_loc = new_loc;
 		data->size_part_descs = new_size;
 	}
+	data->part_descs_loc[data->num_part_descs].partnum = partnum;
 	return &(data->part_descs_loc[data->num_part_descs++].rec);
 }
 

include/linux/quotaops.h

@@ -44,14 +44,7 @@ int dquot_initialize(struct inode *inode);
 bool dquot_initialize_needed(struct inode *inode);
 void dquot_drop(struct inode *inode);
 struct dquot *dqget(struct super_block *sb, struct kqid qid);
-static inline struct dquot *dqgrab(struct dquot *dquot)
-{
-	/* Make sure someone else has active reference to dquot */
-	WARN_ON_ONCE(!atomic_read(&dquot->dq_count));
-	WARN_ON_ONCE(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
-	atomic_inc(&dquot->dq_count);
-	return dquot;
-}
+struct dquot *dqgrab(struct dquot *dquot);
 
 static inline bool dquot_is_busy(struct dquot *dquot)
 {