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panic in removal_remap test on 4K devices

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If the zfs_remove_max_segment tunable is changed to be not a multiple of
the sector size, then the device removal code will malfunction and try
to create mappings that are smaller than one sector, leading to a panic.

On debug bits this assertion will fail in spa_vdev_copy_segment():
    ASSERT3U(DVA_GET_ASIZE(&dst), ==, size);

On nondebug, the system panics with a stack like:
    metaslab_free_concrete()
    metaslab_free_impl()
    metaslab_free_impl_cb()
    vdev_indirect_remap()
    free_from_removing_vdev()
    metaslab_free_impl()
    metaslab_free_dva()
    metaslab_free()

Fortunately, the default for zfs_remove_max_segment is 1MB, so this
can't occur by default.  We hit it during this test because
removal_remap.ksh changes zfs_remove_max_segment to 1KB. When testing on
4KB-sector disks, we hit the bug.

This change makes the zfs_remove_max_segment tunable more robust,
automatically rounding it up to a multiple of the sector size. We also
turn some key assertions into VERIFY's so that similar bugs would be
caught before they are encoded on disk (and thus avoid a
panic-reboot-loop).

Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-61342
Closes #8893
This commit is contained in:
Matthew Ahrens
2019-06-13 13:12:39 -07:00
committed by Tony Hutter
parent 592ee2e6dd
commit 6083f40387
4 changed files with 59 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/sys/vdev_removal.h
+4 -4
View File
@@ -14,7 +14,7 @@
*/
/*
* Copyright (c) 2014, 2017 by Delphix. All rights reserved.
* Copyright (c) 2014, 2019 by Delphix. All rights reserved.
*/
#ifndef _SYS_VDEV_REMOVAL_H
@@ -81,13 +81,13 @@ extern void spa_vdev_condense_suspend(spa_t *);
extern int spa_vdev_remove(spa_t *, uint64_t, boolean_t);
extern void free_from_removing_vdev(vdev_t *, uint64_t, uint64_t);
extern int spa_removal_get_stats(spa_t *, pool_removal_stat_t *);
extern void svr_sync(spa_t *spa, dmu_tx_t *tx);
extern void svr_sync(spa_t *, dmu_tx_t *);
extern void spa_vdev_remove_suspend(spa_t *);
extern int spa_vdev_remove_cancel(spa_t *);
extern void spa_vdev_removal_destroy(spa_vdev_removal_t *svr);
extern void spa_vdev_removal_destroy(spa_vdev_removal_t *);
extern uint64_t spa_remove_max_segment(spa_t *);
extern int vdev_removal_max_span;
extern int zfs_remove_max_segment;
#ifdef __cplusplus
}