[PATCH 09/48] xfs: factor out xlog_recover_validate_ophdr()

[Dave Chinner <dgc@kernel.org>]

Factor the existing operation header checks out of
xlog_recover_process_ophdr() into a dedicated helper to centralise ophdr
validation. Later patches add validation of the remaining ophdr fields here.
The ASSERT(0) and WARN_ON(1) are dropped as they add nothing over the logged
message and returned error, and they fire on expected corrupt input.

Assisted-by: LLM
Signed-off-by: Dave Chinner <dgc@kernel.org>
---
 fs/xfs/xfs_log_recover.c | 55 ++++++++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 19 deletions(-)

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index f2c814f1e78e..1e0b8f2affe3 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -2638,39 +2638,56 @@ xlog_recover_ophdr_to_trans(
 	return NULL;
 }
 
+/*
+ * Validate an operation header decoded from the journal before it is used to
+ * drive transaction recovery. The ophdr and its data region come straight from
+ * the on-disk log and cannot be trusted, so check the fields for known values
+ * and obvious corruption here, in one place, before anything acts on them.
+ */
 STATIC int
-xlog_recover_process_ophdr(
+xlog_recover_validate_ophdr(
 	struct xlog		*log,
-	struct hlist_head	rhash[],
-	struct xlog_rec_header	*rhead,
 	struct xlog_op_header	*ohead,
 	char			*dp,
-	char			*end,
-	int			pass,
-	struct list_head	*buffer_list)
+	char			*end)
 {
-	struct xlog_recover	*trans;
-	unsigned int		len;
-	int			error;
+	unsigned int		len = be32_to_cpu(ohead->oh_len);
+
+	/* Check the ophdr contains all the data it is supposed to contain. */
+	if (dp + len > end) {
+		xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
+		return -EFSCORRUPTED;
+	}
 
 	/* Do we understand who wrote this op? */
 	if (ohead->oh_clientid != XFS_TRANSACTION &&
 	    ohead->oh_clientid != XFS_LOG) {
 		xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
 			__func__, ohead->oh_clientid);
-		ASSERT(0);
 		return -EFSCORRUPTED;
 	}
 
-	/*
-	 * Check the ophdr contains all the data it is supposed to contain.
-	 */
-	len = be32_to_cpu(ohead->oh_len);
-	if (dp + len > end) {
-		xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
-		WARN_ON(1);
-		return -EFSCORRUPTED;
-	}
+	return 0;
+}
+
+STATIC int
+xlog_recover_process_ophdr(
+	struct xlog		*log,
+	struct hlist_head	rhash[],
+	struct xlog_rec_header	*rhead,
+	struct xlog_op_header	*ohead,
+	char			*dp,
+	char			*end,
+	int			pass,
+	struct list_head	*buffer_list)
+{
+	struct xlog_recover	*trans;
+	unsigned int		len = be32_to_cpu(ohead->oh_len);
+	int			error;
+
+	error = xlog_recover_validate_ophdr(log, ohead, dp, end);
+	if (error)
+		return error;
 
 	trans = xlog_recover_ophdr_to_trans(rhash, rhead, ohead);
 	if (!trans) {
-- 
2.55.0