From d519da41e2b789f2cbd705cd8cec0bb92be4838d Mon Sep 17 00:00:00 2001
From: Marco Benatto <mbenatto@redhat.com>
Date: Fri, 1 Feb 2019 09:12:20 -0800
Subject: xfs: Introduce XFS_PTAG_VERIFIER_ERROR panic mask

Currently we have a few PTAGs in place allowing us to transform a filesystem
error in a BUG() call.  However, we don't have a panic tag for corrupt
metadata, so introduce XFS_PTAG_VERIFIER_ERROR so that the administrator can
use the fs.xfs.panic_mask sysctl knob to convert any error detected by buffer
verifiers into a kernel panic.

Signed-off-by: Marco Benatto <mbenatto@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
[darrick: light editing of commit message]
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 Documentation/filesystems/xfs.txt | 3 ++-
 fs/xfs/xfs_error.c                | 3 ++-
 fs/xfs/xfs_error.h                | 1 +
 fs/xfs/xfs_globals.c              | 2 +-
 4 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt
index 9ccfd1bc6201..a5cbb5e0e3db 100644
--- a/Documentation/filesystems/xfs.txt
+++ b/Documentation/filesystems/xfs.txt
@@ -272,7 +272,7 @@ The following sysctls are available for the XFS filesystem:
 		XFS_ERRLEVEL_LOW:       1
 		XFS_ERRLEVEL_HIGH:      5
 
-  fs.xfs.panic_mask		(Min: 0  Default: 0  Max: 255)
+  fs.xfs.panic_mask		(Min: 0  Default: 0  Max: 256)
 	Causes certain error conditions to call BUG(). Value is a bitmask;
 	OR together the tags which represent errors which should cause panics:
 
@@ -285,6 +285,7 @@ The following sysctls are available for the XFS filesystem:
 		XFS_PTAG_SHUTDOWN_IOERROR       0x00000020
 		XFS_PTAG_SHUTDOWN_LOGERROR      0x00000040
 		XFS_PTAG_FSBLOCK_ZERO           0x00000080
+		XFS_PTAG_VERIFIER_ERROR         0x00000100
 
 	This option is intended for debugging only.
 
diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
index 9866f542e77b..57a85410a8c6 100644
--- a/fs/xfs/xfs_error.c
+++ b/fs/xfs/xfs_error.c
@@ -357,7 +357,8 @@ xfs_buf_verifier_error(
 	fa = failaddr ? failaddr : __return_address;
 	__xfs_buf_ioerror(bp, error, fa);
 
-	xfs_alert(mp, "Metadata %s detected at %pS, %s block 0x%llx %s",
+	xfs_alert_tag(mp, XFS_PTAG_VERIFIER_ERROR,
+		  "Metadata %s detected at %pS, %s block 0x%llx %s",
 		  bp->b_error == -EFSBADCRC ? "CRC error" : "corruption",
 		  fa, bp->b_ops->name, bp->b_bn, name);
 
diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h
index 246d3e989c6c..602aa7d62b66 100644
--- a/fs/xfs/xfs_error.h
+++ b/fs/xfs/xfs_error.h
@@ -98,5 +98,6 @@ extern int xfs_errortag_clearall(struct xfs_mount *mp);
 #define		XFS_PTAG_SHUTDOWN_IOERROR	0x00000020
 #define		XFS_PTAG_SHUTDOWN_LOGERROR	0x00000040
 #define		XFS_PTAG_FSBLOCK_ZERO		0x00000080
+#define		XFS_PTAG_VERIFIER_ERROR		0x00000100
 
 #endif	/* __XFS_ERROR_H__ */
diff --git a/fs/xfs/xfs_globals.c b/fs/xfs/xfs_globals.c
index 5169e84ae382..d0d377384120 100644
--- a/fs/xfs/xfs_globals.c
+++ b/fs/xfs/xfs_globals.c
@@ -16,7 +16,7 @@ xfs_param_t xfs_params = {
 			  /*	MIN		DFLT		MAX	*/
 	.sgid_inherit	= {	0,		0,		1	},
 	.symlink_mode	= {	0,		0,		1	},
-	.panic_mask	= {	0,		0,		255	},
+	.panic_mask	= {	0,		0,		256	},
 	.error_level	= {	0,		3,		11	},
 	.syncd_timer	= {	1*100,		30*100,		7200*100},
 	.stats_clear	= {	0,		0,		1	},
-- 
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