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

4 files changed, 20 insertions, 10 deletions

diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 007eee794bd1..adf0f31fbddd 100644
--- a/fs/ext2/balloc.c
+++ b/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 @@ restart:
 	__rsv_window_dump((root), (verbose), __func__)
 #else
 #define rsv_window_dump(root, verbose) do {} while (0)
-#endif
+#endif /* EXT2FS_DEBUG */
 
 /**
  * goal_in_my_reservation()
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 6443c298c105..74aca5eb572d 100644
--- a/fs/ext2/inode.c
+++ b/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);
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index bde617a66cec..0d09d22fe708 100644
--- a/fs/ext2/namei.c
+++ b/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;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 4118a3a1f620..19f76d8cb473 100644
--- a/fs/ext2/super.c
+++ b/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 */