xfs: convert drop_writes to use the errortag mechanism

We now have enhanced error injection that can control the frequency
with which errors happen, so convert drop_writes to use this.
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

@@ -55,6 +55,7 @@ static unsigned int xfs_errortag_random_default[] = {
 	XFS_RANDOM_REFCOUNT_FINISH_ONE,
 	XFS_RANDOM_BMAP_FINISH_ONE,
 	XFS_RANDOM_AG_RESV_CRITICAL,
+	XFS_RANDOM_DROP_WRITES,
 };
 
 struct xfs_errortag_attr {
@@ -157,6 +158,7 @@ XFS_ERRORTAG_ATTR_RW(refcount_continue_update,	XFS_ERRTAG_REFCOUNT_CONTINUE_UPDA
 XFS_ERRORTAG_ATTR_RW(refcount_finish_one,	XFS_ERRTAG_REFCOUNT_FINISH_ONE);
 XFS_ERRORTAG_ATTR_RW(bmap_finish_one,	XFS_ERRTAG_BMAP_FINISH_ONE);
 XFS_ERRORTAG_ATTR_RW(ag_resv_critical,	XFS_ERRTAG_AG_RESV_CRITICAL);
+XFS_ERRORTAG_ATTR_RW(drop_writes,	XFS_ERRTAG_DROP_WRITES);
 
 static struct attribute *xfs_errortag_attrs[] = {
 	XFS_ERRORTAG_ATTR_LIST(noerror),
@@ -187,6 +189,7 @@ static struct attribute *xfs_errortag_attrs[] = {
 	XFS_ERRORTAG_ATTR_LIST(refcount_finish_one),
 	XFS_ERRORTAG_ATTR_LIST(bmap_finish_one),
 	XFS_ERRORTAG_ATTR_LIST(ag_resv_critical),
+	XFS_ERRORTAG_ATTR_LIST(drop_writes),
 	NULL,
 };
 

fs/xfs/xfs_error.h

@@ -96,7 +96,16 @@ extern void xfs_verifier_error(struct xfs_buf *bp);
 #define XFS_ERRTAG_REFCOUNT_FINISH_ONE			25
 #define XFS_ERRTAG_BMAP_FINISH_ONE			26
 #define XFS_ERRTAG_AG_RESV_CRITICAL			27
-#define XFS_ERRTAG_MAX					28
+/*
+ * DEBUG mode instrumentation to test and/or trigger delayed allocation
+ * block killing in the event of failed writes. When enabled, all
+ * buffered writes are silenty dropped and handled as if they failed.
+ * All delalloc blocks in the range of the write (including pre-existing
+ * delalloc blocks!) are tossed as part of the write failure error
+ * handling sequence.
+ */
+#define XFS_ERRTAG_DROP_WRITES				28
+#define XFS_ERRTAG_MAX					29
 
 /*
  * Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
@@ -129,6 +138,7 @@ extern void xfs_verifier_error(struct xfs_buf *bp);
 #define XFS_RANDOM_REFCOUNT_FINISH_ONE			1
 #define XFS_RANDOM_BMAP_FINISH_ONE			1
 #define XFS_RANDOM_AG_RESV_CRITICAL			4
+#define XFS_RANDOM_DROP_WRITES				1
 
 #ifdef DEBUG
 extern int xfs_errortag_init(struct xfs_mount *mp);

fs/xfs/xfs_iomap.c

@@ -1097,7 +1097,7 @@ xfs_file_iomap_end_delalloc(
 	 * Behave as if the write failed if drop writes is enabled. Set the NEW
 	 * flag to force delalloc cleanup.
 	 */
-	if (xfs_mp_drop_writes(mp)) {
+	if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_DROP_WRITES)) {
 		iomap->flags |= IOMAP_F_NEW;
 		written = 0;
 	}

fs/xfs/xfs_mount.h

@@ -205,16 +205,6 @@ typedef struct xfs_mount {
 	 */
 	unsigned int		*m_errortag;
 	struct xfs_kobj		m_errortag_kobj;
-
-	/*
-	 * DEBUG mode instrumentation to test and/or trigger delayed allocation
-	 * block killing in the event of failed writes. When enabled, all
-	 * buffered writes are silenty dropped and handled as if they failed.
-	 * All delalloc blocks in the range of the write (including pre-existing
-	 * delalloc blocks!) are tossed as part of the write failure error
-	 * handling sequence.
-	 */
-	bool			m_drop_writes;
 #endif
 } xfs_mount_t;
 
@@ -333,20 +323,6 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
 	return (xfs_agblock_t) do_div(ld, mp->m_sb.sb_agblocks);
 }
 
-#ifdef DEBUG
-static inline bool
-xfs_mp_drop_writes(struct xfs_mount *mp)
-{
-	return mp->m_drop_writes;
-}
-#else
-static inline bool
-xfs_mp_drop_writes(struct xfs_mount *mp)
-{
-	return 0;
-}
-#endif
-
 /* per-AG block reservation data structures*/
 enum xfs_ag_resv_type {
 	XFS_AG_RESV_NONE = 0,

fs/xfs/xfs_sysfs.c

@@ -90,49 +90,7 @@ to_mp(struct kobject *kobject)
 	return container_of(kobj, struct xfs_mount, m_kobj);
 }
 
-#ifdef DEBUG
-
-STATIC ssize_t
-drop_writes_store(
-	struct kobject		*kobject,
-	const char		*buf,
-	size_t			count)
-{
-	struct xfs_mount	*mp = to_mp(kobject);
-	int			ret;
-	int			val;
-
-	ret = kstrtoint(buf, 0, &val);
-	if (ret)
-		return ret;
-
-	if (val == 1)
-		mp->m_drop_writes = true;
-	else if (val == 0)
-		mp->m_drop_writes = false;
-	else
-		return -EINVAL;
-
-	return count;
-}
-
-STATIC ssize_t
-drop_writes_show(
-	struct kobject		*kobject,
-	char			*buf)
-{
-	struct xfs_mount	*mp = to_mp(kobject);
-
-	return snprintf(buf, PAGE_SIZE, "%d\n", mp->m_drop_writes ? 1 : 0);
-}
-XFS_SYSFS_ATTR_RW(drop_writes);
-
-#endif /* DEBUG */
-
 static struct attribute *xfs_mp_attrs[] = {
-#ifdef DEBUG
-	ATTR_LIST(drop_writes),
-#endif
 	NULL,
 };