From 3efcc87413ab51293f127fb9015ec3947975c2b3 Mon Sep 17 00:00:00 2001
From: Zach Brown <zab@versity.com>
Date: Thu, 26 Apr 2018 10:32:44 -0700
Subject: [PATCH] scoutfs: add corruption messages for namei

Add scoutfs_corruption() calls for corruption associated with mapping
names to inodes.

Signed-off-by: Zach Brown <zab@versity.com>
---
 kmod/src/counters.h |  6 ++++++
 kmod/src/dir.c      | 36 ++++++++++++++++++++++++++++++------
 kmod/src/format.h   |  6 ++++++
 3 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/kmod/src/counters.h b/kmod/src/counters.h
index f552617a..a919b191 100644
--- a/kmod/src/counters.h
+++ b/kmod/src/counters.h
@@ -23,6 +23,12 @@
 	EXPAND_COUNTER(compact_stale_error)			\
 	EXPAND_COUNTER(compact_sticky_upper)			\
 	EXPAND_COUNTER(compact_sticky_written)			\
+	EXPAND_COUNTER(corrupt_dirent_backref_name_len)		\
+	EXPAND_COUNTER(corrupt_dirent_name_len)			\
+	EXPAND_COUNTER(corrupt_dirent_readdir_name_len)		\
+	EXPAND_COUNTER(corrupt_symlink_inode_size)		\
+	EXPAND_COUNTER(corrupt_symlink_missing_item)		\
+	EXPAND_COUNTER(corrupt_symlink_not_null_term)		\
 	EXPAND_COUNTER(data_end_writeback_page)			\
 	EXPAND_COUNTER(data_invalidatepage)			\
 	EXPAND_COUNTER(data_readpage)				\
diff --git a/kmod/src/dir.c b/kmod/src/dir.c
index bf2c052a..292df2d5 100644
--- a/kmod/src/dir.c
+++ b/kmod/src/dir.c
@@ -258,8 +258,11 @@ static int lookup_dirent(struct super_block *sb, u64 dir_ino, const char *name,
 			break;
 
 		ret -= sizeof(struct scoutfs_dirent);
-		/* XXX corruption */
 		if (ret < 1 || ret > SCOUTFS_NAME_LEN) {
+			scoutfs_corruption(sb, SC_DIRENT_NAME_LEN,
+					   corrupt_dirent_name_len,
+					   "dir_ino %llu hash %llu key "SK_FMT" len %d",
+					   dir_ino, hash, SK_ARG(&key), ret);
 			ret = -EIO;
 			goto out;
 		}
@@ -504,8 +507,12 @@ static int scoutfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 		}
 
 		name_len = ret - sizeof(struct scoutfs_dirent);
-		/* XXX corruption */
 		if (name_len < 1 || name_len > SCOUTFS_NAME_LEN) {
+			scoutfs_corruption(sb, SC_DIRENT_READDIR_NAME_LEN,
+					   corrupt_dirent_readdir_name_len,
+					   "dir_ino %llu pos %llu key "SK_FMT" len %d",
+					   scoutfs_ino(inode), file->f_pos,
+					   SK_ARG(&key), name_len);
 			ret = -EIO;
 			goto out;
 		}
@@ -1034,8 +1041,11 @@ static void *scoutfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 
 	size = i_size_read(inode);
 
-	/* XXX corruption */
 	if (size == 0 || size > SCOUTFS_SYMLINK_MAX_SIZE) {
+		scoutfs_corruption(sb, SC_SYMLINK_INODE_SIZE,
+				   corrupt_symlink_inode_size,
+				   "ino %llu size %llu",
+				   scoutfs_ino(inode), (u64)size);
 		ret = -EIO;
 		goto out;
 	}
@@ -1055,10 +1065,21 @@ static void *scoutfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 	ret = symlink_item_ops(sb, SYM_LOOKUP, scoutfs_ino(inode), inode_lock,
 			       path, size);
 
-	/* XXX corruption: missing items or not null term */
-	if (ret == -ENOENT || (ret == 0 && path[size - 1]))
+	if (ret == -ENOENT) {
+		scoutfs_corruption(sb, SC_SYMLINK_MISSING_ITEM,
+				   corrupt_symlink_missing_item,
+				   "ino %llu size %llu", scoutfs_ino(inode),
+				   size);
 		ret = -EIO;
 
+	} else if (ret == 0 && path[size - 1]) {
+		scoutfs_corruption(sb, SC_SYMLINK_NOT_NULL_TERM,
+				   corrupt_symlink_not_null_term,
+				   "ino %llu last %u",
+				   scoutfs_ino(inode), path[size - 1]);
+		ret = -EIO;
+	}
+
 out:
 	if (ret < 0) {
 		kfree(path);
@@ -1229,8 +1250,11 @@ int scoutfs_dir_add_next_linkref(struct super_block *sb, u64 ino,
 		goto out;
 
 	len = ret - sizeof(struct scoutfs_dirent);
-	/* XXX corruption */
 	if (len < 1 || len > SCOUTFS_NAME_LEN) {
+		scoutfs_corruption(sb, SC_DIRENT_BACKREF_NAME_LEN,
+				   corrupt_dirent_backref_name_len,
+				   "ino %llu dir_ino %llu pos %llu key "SK_FMT" len %d",
+				   ino, dir_ino, dir_pos, SK_ARG(&key), len);
 		ret = -EIO;
 		goto out;
 	}
diff --git a/kmod/src/format.h b/kmod/src/format.h
index 8022f36a..54857d24 100644
--- a/kmod/src/format.h
+++ b/kmod/src/format.h
@@ -649,6 +649,12 @@ struct scoutfs_fid {
  * Identifiers for sources of corruption that can generate messages.
  */
 enum {
+	SC_DIRENT_NAME_LEN = 0,
+	SC_DIRENT_BACKREF_NAME_LEN,
+	SC_DIRENT_READDIR_NAME_LEN,
+	SC_SYMLINK_INODE_SIZE,
+	SC_SYMLINK_MISSING_ITEM,
+	SC_SYMLINK_NOT_NULL_TERM,
 	SC_NR_SOURCES,
 };