Always validate checksums for Direct I/O reads

This fixes an oversight in the Direct I/O PR. There is nothing that
stops a process from manipulating the contents of a buffer for a
Direct I/O read while the I/O is in flight. This can lead checksum
verify failures. However, the disk contents are still correct, and this
would lead to false reporting of checksum validation failures.

To remedy this, all Direct I/O reads that have a checksum verification
failure are treated as suspicious. In the event a checksum validation
failure occurs for a Direct I/O read, then the I/O request will be
reissued though the ARC. This allows for actual validation to happen and
removes any possibility of the buffer being manipulated after the I/O
has been issued.

Just as with Direct I/O write checksum validation failures, Direct I/O
read checksum validation failures are reported though zpool status -d in
the DIO column. Also the zevent has been updated to have both:
1. dio_verify_wr -> Checksum verification failure for writes
2. dio_verify_rd -> Checksum verification failure for reads.
This allows for determining what I/O operation was the culprit for the
checksum verification failure. All DIO errors are reported only on the
top-level VDEV.

Even though FreeBSD can write protect pages (stable pages) it still has
the same issue as Linux with Direct I/O reads.

This commit updates the following:
1. Propogates checksum failures for reads all the way up to the
   top-level VDEV.
2. Reports errors through zpool status -d as DIO.
3. Has two zevents for checksum verify errors with Direct I/O. One for
   read and one for write.
4. Updates FreeBSD ABD code to also check for ABD_FLAG_FROM_PAGES and
   handle ABD buffer contents validation the same as Linux.
5. Updated manipulate_user_buffer.c to also manipulate a buffer while a
   Direct I/O read is taking place.
6. Adds a new ZTS test case dio_read_verify that stress tests the new
   code.
7. Updated man pages.
8. Added an IMPLY statement to zio_checksum_verify() to make sure that
   Direct I/O reads are not issued as speculative.
9. Removed self healing through mirror, raidz, and dRAID VDEVs for
   Direct I/O reads.

This issue was first observed when installing a Windows 11 VM on a ZFS
dataset with the dataset property direct set to always. The zpool
devices would report checksum failures, but running a subsequent zpool
scrub would not repair any data and report no errors.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes #16598

include/sys/zio.h

@@ -208,25 +208,25 @@ typedef uint64_t zio_flag_t;
 #define	ZIO_FLAG_PROBE		(1ULL << 16)
 #define	ZIO_FLAG_TRYHARD	(1ULL << 17)
 #define	ZIO_FLAG_OPTIONAL	(1ULL << 18)
-
+#define	ZIO_FLAG_DIO_READ	(1ULL << 19)
 #define	ZIO_FLAG_VDEV_INHERIT	(ZIO_FLAG_DONT_QUEUE - 1)
 
 	/*
 	 * Flags not inherited by any children.
 	 */
-#define	ZIO_FLAG_DONT_QUEUE	(1ULL << 19)	/* must be first for INHERIT */
-#define	ZIO_FLAG_DONT_PROPAGATE	(1ULL << 20)
-#define	ZIO_FLAG_IO_BYPASS	(1ULL << 21)
-#define	ZIO_FLAG_IO_REWRITE	(1ULL << 22)
-#define	ZIO_FLAG_RAW_COMPRESS	(1ULL << 23)
-#define	ZIO_FLAG_RAW_ENCRYPT	(1ULL << 24)
-#define	ZIO_FLAG_GANG_CHILD	(1ULL << 25)
-#define	ZIO_FLAG_DDT_CHILD	(1ULL << 26)
-#define	ZIO_FLAG_GODFATHER	(1ULL << 27)
-#define	ZIO_FLAG_NOPWRITE	(1ULL << 28)
-#define	ZIO_FLAG_REEXECUTED	(1ULL << 29)
-#define	ZIO_FLAG_DELEGATED	(1ULL << 30)
-#define	ZIO_FLAG_DIO_CHKSUM_ERR	(1ULL << 31)
+#define	ZIO_FLAG_DONT_QUEUE	(1ULL << 20)	/* must be first for INHERIT */
+#define	ZIO_FLAG_DONT_PROPAGATE	(1ULL << 21)
+#define	ZIO_FLAG_IO_BYPASS	(1ULL << 22)
+#define	ZIO_FLAG_IO_REWRITE	(1ULL << 23)
+#define	ZIO_FLAG_RAW_COMPRESS	(1ULL << 24)
+#define	ZIO_FLAG_RAW_ENCRYPT	(1ULL << 25)
+#define	ZIO_FLAG_GANG_CHILD	(1ULL << 26)
+#define	ZIO_FLAG_DDT_CHILD	(1ULL << 27)
+#define	ZIO_FLAG_GODFATHER	(1ULL << 28)
+#define	ZIO_FLAG_NOPWRITE	(1ULL << 29)
+#define	ZIO_FLAG_REEXECUTED	(1ULL << 30)
+#define	ZIO_FLAG_DELEGATED	(1ULL << 31)
+#define	ZIO_FLAG_DIO_CHKSUM_ERR	(1ULL << 32)
 
 #define	ZIO_ALLOCATOR_NONE	(-1)
 #define	ZIO_HAS_ALLOCATOR(zio)	((zio)->io_allocator != ZIO_ALLOCATOR_NONE)
@@ -647,6 +647,7 @@ extern void zio_vdev_io_redone(zio_t *zio);
 extern void zio_change_priority(zio_t *pio, zio_priority_t priority);
 
 extern void zio_checksum_verified(zio_t *zio);
+extern void zio_dio_chksum_verify_error_report(zio_t *zio);
 extern int zio_worst_error(int e1, int e2);
 
 extern enum zio_checksum zio_checksum_select(enum zio_checksum child,