OpenZFS 8961 - SPA load/import should tell us why it failed

Problem
=======

When we fail to open or import a storage pool, we typically don't
get any additional diagnostic information, just "no pool found" or
"can not import".

While there may be no additional user-consumable information, we should
at least make this situation easier to debug/diagnose for developers
and support.  For example, we could start by using `zfs_dbgmsg()`
to log each thing that we try when importing, and which things
failed. E.g. "tried uberblock of txg X from label Y of device Z". Also,
we could log each of the stages that we go through in `spa_load_impl()`.

Solution
========

Following the cleanup to `spa_load_impl()`, debug messages have been
added to every point of failure in that function. Additionally,
debug messages have been added to strategic places, such as
`vdev_disk_open()`.

Authored by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Andrew Stormont <andyjstormont@gmail.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Tim Chase <tim@chase2k.com>

OpenZFS-issue: https://illumos.org/issues/8961
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/418079e0
Closes #7459
This commit is contained in:
Pavel Zakharov
2016-03-10 10:16:02 -05:00
committed by Brian Behlendorf
parent ca0845d59e
commit 4a0ee12af8
7 changed files with 281 additions and 75 deletions
+28
View File
@@ -373,6 +373,34 @@ int spa_asize_inflation = 24;
int spa_slop_shift = 5;
uint64_t spa_min_slop = 128 * 1024 * 1024;
/*PRINTFLIKE2*/
void
spa_load_failed(spa_t *spa, const char *fmt, ...)
{
va_list adx;
char buf[256];
va_start(adx, fmt);
(void) vsnprintf(buf, sizeof (buf), fmt, adx);
va_end(adx);
zfs_dbgmsg("spa_load(%s): FAILED: %s", spa->spa_name, buf);
}
/*PRINTFLIKE2*/
void
spa_load_note(spa_t *spa, const char *fmt, ...)
{
va_list adx;
char buf[256];
va_start(adx, fmt);
(void) vsnprintf(buf, sizeof (buf), fmt, adx);
va_end(adx);
zfs_dbgmsg("spa_load(%s): %s", spa->spa_name, buf);
}
/*
* ==========================================================================
* SPA config locking