Report pool suspended due to MMP

When the pool is suspended, record whether it was due to an I/O error or
due to MMP writes failing to succeed within the required time.

Change spa_suspended from uint8_t to zio_suspend_reason_t to store the
reason.

When userspace queries pool status via spa_tryimport(), report the
reason the pool was suspended in a new key,
ZPOOL_CONFIG_SUSPENDED_REASON.

In libzfs, when interpreting the returned config nvlist, report
suspension due to MMP with a new pool status enum value,
ZPOOL_STATUS_IO_FAILURE_MMP.

In status_callback(), which generates and emits the message when 'zpool
status' is executed, add a case to print an appropriate message for the
new pool status enum value.

Reviewed-by: George Melikov <[email protected]>
Reviewed-by: Giuseppe Di Natale <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Signed-off-by: Olaf Faaland <[email protected]>
Closes #7296 

1 files changed, 7 insertions, 1 deletions

diff --git a/include/sys/zio.h b/include/sys/zio.h
index 8d5f99d46..9d3adb7f5 100644
--- a/include/sys/zio.h
+++ b/include/sys/zio.h
@@ -167,6 +167,12 @@ enum zio_encrypt {
 #define	ZIO_FAILURE_MODE_CONTINUE	1
 #define	ZIO_FAILURE_MODE_PANIC		2
 
+typedef enum zio_suspend_reason {
+	ZIO_SUSPEND_NONE = 0,
+	ZIO_SUSPEND_IOERR,
+	ZIO_SUSPEND_MMP,
+} zio_suspend_reason_t;
+
 enum zio_flag {
 	/*
 	 * Flags inherited by gang, ddt, and vdev children,
@@ -610,7 +616,7 @@ extern enum zio_checksum zio_checksum_dedup_select(spa_t *spa,
 extern enum zio_compress zio_compress_select(spa_t *spa,
     enum zio_compress child, enum zio_compress parent);
 
-extern void zio_suspend(spa_t *spa, zio_t *zio);
+extern void zio_suspend(spa_t *spa, zio_t *zio, zio_suspend_reason_t);
 extern int zio_resume(spa_t *spa);
 extern void zio_resume_wait(spa_t *spa);