xfs: make errortag a per-mountpoint structure

Remove the xfs_etest structure in favor of a per-mountpoint structure.
This will give us the flexibility to set as many error injection points
as we want, and later enable us to set up sysfs knobs to set the trigger
frequency as we wish.  This comes at a cost of higher memory use, but
unti we hit 1024 injection points (we're at 29) or a lot of mounts this
shouldn't be a huge issue.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>

fs/xfs/xfs_error.c

@@ -25,100 +25,106 @@
 
 #ifdef DEBUG
 
-int	xfs_etest[XFS_NUM_INJECT_ERROR];
-int64_t	xfs_etest_fsid[XFS_NUM_INJECT_ERROR];
-char *	xfs_etest_fsname[XFS_NUM_INJECT_ERROR];
-int	xfs_error_test_active;
+static unsigned int xfs_errortag_random_default[] = {
+	XFS_RANDOM_DEFAULT,
+	XFS_RANDOM_IFLUSH_1,
+	XFS_RANDOM_IFLUSH_2,
+	XFS_RANDOM_IFLUSH_3,
+	XFS_RANDOM_IFLUSH_4,
+	XFS_RANDOM_IFLUSH_5,
+	XFS_RANDOM_IFLUSH_6,
+	XFS_RANDOM_DA_READ_BUF,
+	XFS_RANDOM_BTREE_CHECK_LBLOCK,
+	XFS_RANDOM_BTREE_CHECK_SBLOCK,
+	XFS_RANDOM_ALLOC_READ_AGF,
+	XFS_RANDOM_IALLOC_READ_AGI,
+	XFS_RANDOM_ITOBP_INOTOBP,
+	XFS_RANDOM_IUNLINK,
+	XFS_RANDOM_IUNLINK_REMOVE,
+	XFS_RANDOM_DIR_INO_VALIDATE,
+	XFS_RANDOM_BULKSTAT_READ_CHUNK,
+	XFS_RANDOM_IODONE_IOERR,
+	XFS_RANDOM_STRATREAD_IOERR,
+	XFS_RANDOM_STRATCMPL_IOERR,
+	XFS_RANDOM_DIOWRITE_IOERR,
+	XFS_RANDOM_BMAPIFORMAT,
+	XFS_RANDOM_FREE_EXTENT,
+	XFS_RANDOM_RMAP_FINISH_ONE,
+	XFS_RANDOM_REFCOUNT_CONTINUE_UPDATE,
+	XFS_RANDOM_REFCOUNT_FINISH_ONE,
+	XFS_RANDOM_BMAP_FINISH_ONE,
+	XFS_RANDOM_AG_RESV_CRITICAL,
+};
 
 int
-xfs_error_test(int error_tag, int *fsidp, char *expression,
-	       int line, char *file, unsigned long randfactor)
+xfs_errortag_init(
+	struct xfs_mount	*mp)
 {
-	int i;
-	int64_t fsid;
-
-	if (prandom_u32() % randfactor)
+	mp->m_errortag = kmem_zalloc(sizeof(unsigned int) * XFS_ERRTAG_MAX,
+			KM_SLEEP | KM_MAYFAIL);
+	if (!mp->m_errortag)
+		return -ENOMEM;
 	return 0;
+}
 
-	memcpy(&fsid, fsidp, sizeof(xfs_fsid_t));
+void
+xfs_errortag_del(
+	struct xfs_mount	*mp)
+{
+	kmem_free(mp->m_errortag);
+}
 
-	for (i = 0; i < XFS_NUM_INJECT_ERROR; i++)  {
-		if (xfs_etest[i] == error_tag && xfs_etest_fsid[i] == fsid) {
-			xfs_warn(NULL,
-	"Injecting error (%s) at file %s, line %d, on filesystem \"%s\"",
-				expression, file, line, xfs_etest_fsname[i]);
-			return 1;
-		}
-	}
+bool
+xfs_errortag_test(
+	struct xfs_mount	*mp,
+	const char		*expression,
+	const char		*file,
+	int			line,
+	unsigned int		error_tag)
+{
+	unsigned int		randfactor;
 
-	return 0;
+	ASSERT(error_tag < XFS_ERRTAG_MAX);
+	randfactor = mp->m_errortag[error_tag];
+	if (!randfactor || prandom_u32() % randfactor)
+		return false;
+
+	xfs_warn_ratelimited(mp,
+"Injecting error (%s) at file %s, line %d, on filesystem \"%s\"",
+			expression, file, line, mp->m_fsname);
+	return true;
 }
 
 int
-xfs_errortag_add(unsigned int error_tag, xfs_mount_t *mp)
+xfs_errortag_set(
+	struct xfs_mount	*mp,
+	unsigned int		error_tag,
+	unsigned int		tag_value)
 {
-	int i;
-	int len;
-	int64_t fsid;
-
 	if (error_tag >= XFS_ERRTAG_MAX)
 		return -EINVAL;
 
-	memcpy(&fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t));
-
-	for (i = 0; i < XFS_NUM_INJECT_ERROR; i++)  {
-		if (xfs_etest_fsid[i] == fsid && xfs_etest[i] == error_tag) {
-			xfs_warn(mp, "error tag #%d on", error_tag);
-			return 0;
-		}
-	}
-
-	for (i = 0; i < XFS_NUM_INJECT_ERROR; i++)  {
-		if (xfs_etest[i] == 0) {
-			xfs_warn(mp, "Turned on XFS error tag #%d",
-				error_tag);
-			xfs_etest[i] = error_tag;
-			xfs_etest_fsid[i] = fsid;
-			len = strlen(mp->m_fsname);
-			xfs_etest_fsname[i] = kmem_alloc(len + 1, KM_SLEEP);
-			strcpy(xfs_etest_fsname[i], mp->m_fsname);
-			xfs_error_test_active++;
+	mp->m_errortag[error_tag] = tag_value;
 	return 0;
-		}
-	}
-
-	xfs_warn(mp, "error tag overflow, too many turned on");
-
-	return 1;
 }
 
 int
-xfs_errortag_clearall(xfs_mount_t *mp, int loud)
+xfs_errortag_add(
+	struct xfs_mount	*mp,
+	unsigned int		error_tag)
 {
-	int64_t fsid;
-	int cleared = 0;
-	int i;
-
-	memcpy(&fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t));
-
-
-	for (i = 0; i < XFS_NUM_INJECT_ERROR; i++) {
-		if ((fsid == 0LL || xfs_etest_fsid[i] == fsid) &&
-		     xfs_etest[i] != 0) {
-			cleared = 1;
-			xfs_warn(mp, "Clearing XFS error tag #%d",
-				xfs_etest[i]);
-			xfs_etest[i] = 0;
-			xfs_etest_fsid[i] = 0LL;
-			kmem_free(xfs_etest_fsname[i]);
-			xfs_etest_fsname[i] = NULL;
-			xfs_error_test_active--;
-		}
-	}
+	if (error_tag >= XFS_ERRTAG_MAX)
+		return -EINVAL;
 
-	if (loud || cleared)
-		xfs_warn(mp, "Cleared all XFS error tags for filesystem");
+	return xfs_errortag_set(mp, error_tag,
+			xfs_errortag_random_default[error_tag]);
+}
 
+int
+xfs_errortag_clearall(
+	struct xfs_mount	*mp)
+{
+	memset(mp->m_errortag, 0, sizeof(unsigned int) * XFS_ERRTAG_MAX);
 	return 0;
 }
 #endif /* DEBUG */

fs/xfs/xfs_error.h

@@ -131,21 +131,24 @@ extern void xfs_verifier_error(struct xfs_buf *bp);
 #define XFS_RANDOM_AG_RESV_CRITICAL			4
 
 #ifdef DEBUG
-extern int xfs_error_test_active;
-extern int xfs_error_test(int, int *, char *, int, char *, unsigned long);
-
-#define	XFS_NUM_INJECT_ERROR				10
+extern int xfs_errortag_init(struct xfs_mount *mp);
+extern void xfs_errortag_del(struct xfs_mount *mp);
+extern bool xfs_errortag_test(struct xfs_mount *mp, const char *expression,
+		const char *file, int line, unsigned int error_tag);
 #define XFS_TEST_ERROR(expr, mp, tag, rf)		\
-	((expr) || (xfs_error_test_active && \
-	 xfs_error_test((tag), (mp)->m_fixedfsid, "expr", __LINE__, __FILE__, \
-			(rf))))
+	((expr) || xfs_errortag_test((mp), #expr, __FILE__, __LINE__, (tag)))
 
-extern int xfs_errortag_add(unsigned int error_tag, struct xfs_mount *mp);
-extern int xfs_errortag_clearall(struct xfs_mount *mp, int loud);
+extern int xfs_errortag_set(struct xfs_mount *mp, unsigned int error_tag,
+		unsigned int tag_value);
+extern int xfs_errortag_add(struct xfs_mount *mp, unsigned int error_tag);
+extern int xfs_errortag_clearall(struct xfs_mount *mp);
 #else
+#define xfs_errortag_init(mp)			(0)
+#define xfs_errortag_del(mp)
 #define XFS_TEST_ERROR(expr, mp, tag, rf)	(expr)
-#define xfs_errortag_add(tag, mp)		(ENOSYS)
-#define xfs_errortag_clearall(mp, loud)		(ENOSYS)
+#define xfs_errortag_set(mp, tag, val)		(ENOSYS)
+#define xfs_errortag_add(mp, tag)		(ENOSYS)
+#define xfs_errortag_clearall(mp)		(ENOSYS)
 #endif /* DEBUG */
 
 /*

fs/xfs/xfs_ioctl.c

@@ -2037,14 +2037,14 @@ xfs_file_ioctl(
 		if (copy_from_user(&in, arg, sizeof(in)))
 			return -EFAULT;
 
-		return xfs_errortag_add(in.errtag, mp);
+		return xfs_errortag_add(mp, in.errtag);
 	}
 
 	case XFS_IOC_ERROR_CLEARALL:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 
-		return xfs_errortag_clearall(mp, 1);
+		return xfs_errortag_clearall(mp);
 
 	case XFS_IOC_FREE_EOFBLOCKS: {
 		struct xfs_fs_eofblocks eofb;

fs/xfs/xfs_mount.c

@@ -720,10 +720,13 @@ xfs_mountfs(
 	if (error)
 		goto out_del_stats;
 
+	error = xfs_errortag_init(mp);
+	if (error)
+		goto out_remove_error_sysfs;
 
 	error = xfs_uuid_mount(mp);
 	if (error)
-		goto out_remove_error_sysfs;
+		goto out_remove_errortag;
 
 	/*
 	 * Set the minimum read and write sizes
@@ -1042,6 +1045,8 @@ xfs_mountfs(
 	xfs_da_unmount(mp);
  out_remove_uuid:
 	xfs_uuid_unmount(mp);
+ out_remove_errortag:
+	xfs_errortag_del(mp);
  out_remove_error_sysfs:
 	xfs_error_sysfs_del(mp);
  out_del_stats:
@@ -1145,10 +1150,11 @@ xfs_unmountfs(
 	xfs_uuid_unmount(mp);
 
 #if defined(DEBUG)
-	xfs_errortag_clearall(mp, 0);
+	xfs_errortag_clearall(mp);
 #endif
 	xfs_free_perag(mp);
 
+	xfs_errortag_del(mp);
 	xfs_error_sysfs_del(mp);
 	xfs_sysfs_del(&mp->m_stats.xs_kobj);
 	xfs_sysfs_del(&mp->m_kobj);

fs/xfs/xfs_mount.h

@@ -198,6 +198,13 @@ typedef struct xfs_mount {
 
 	bool			m_fail_unmount;
 #ifdef DEBUG
+	/*
+	 * Frequency with which errors are injected.  Replaces xfs_etest; the
+	 * value stored in here is the inverse of the frequency with which the
+	 * error triggers.  1 = always, 2 = half the time, etc.
+	 */
+	unsigned int		*m_errortag;
+
 	/*
 	 * DEBUG mode instrumentation to test and/or trigger delayed allocation
 	 * block killing in the event of failed writes. When enabled, all