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range_tree: Add zfs_recover_rt parameter and extra debug info #17094

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range_tree: Add zfs_recover_rt parameter and extra debug info #17094

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32 changes: 32 additions & 0 deletions include/sys/range_tree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,32 @@ typedef enum zfs_range_seg_type {
ZFS_RANGE_SEG_NUM_TYPES,
} zfs_range_seg_type_t;

/*
* Range tree behavior flags.
*
* The UC (use case) flags are intended to support the zfs_recover_rt mode.
* The range tree's logic needs to know the context in order to correctly
* recover from an unexpected situation by exchanging potential data loss for
* a potential space leak:
*
* - If it knows that the tree represents allocated space then it should better
* perform an unexpected addition to the tree.
*
* - Similarly, if it's about free space (aka allocatable) then it should
* perform unexpected removals instead of silently ignoring the issue.
*
* The generic case means to simply ignore unexpected additions/removals as
* a recovery mechanism, without special treatment.
*
* Unexpected actions are logged with extra details such as a range tree
* name string, which can be marked as dynamic to be freed along with the tree
* instance destruction.
*/
#define ZFS_RANGE_TREE_F_UC_GENERIC (1 << 0)
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I don't think "GENERIC" is really meaningful. Easier and cleaner I think would be just to pass 0 if we can't say anything better (we really should).

#define ZFS_RANGE_TREE_F_UC_ALLOCATED_SPACE (1 << 1)
#define ZFS_RANGE_TREE_F_UC_FREE_SPACE (1 << 2)
#define ZFS_RANGE_TREE_F_DYN_NAME (1 << 3)

/*
* Note: the range_tree may not be accessed concurrently; consumers
* must provide external locking if required.
Expand All @@ -67,6 +93,9 @@ typedef struct zfs_range_tree {
void *rt_arg;
uint64_t rt_gap; /* allowable inter-segment gap */

uint64_t rt_flags;
const char *rt_name; /* details for debugging */

/*
* The rt_histogram maintains a histogram of ranges. Each bucket,
* rt_histogram[i], contains the number of ranges whose size is:
Expand Down Expand Up @@ -280,6 +309,9 @@ zfs_range_tree_t *zfs_range_tree_create_gap(const zfs_range_tree_ops_t *ops,
uint64_t gap);
zfs_range_tree_t *zfs_range_tree_create(const zfs_range_tree_ops_t *ops,
zfs_range_seg_type_t type, void *arg, uint64_t start, uint64_t shift);
zfs_range_tree_t *zfs_range_tree_create_flags(const zfs_range_tree_ops_t *ops,
zfs_range_seg_type_t type, void *arg, uint64_t start, uint64_t shift,
uint64_t flags, const char *name);
void zfs_range_tree_destroy(zfs_range_tree_t *rt);
boolean_t zfs_range_tree_contains(zfs_range_tree_t *rt, uint64_t start,
uint64_t size);
Expand Down
6 changes: 6 additions & 0 deletions man/man4/zfs.4
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Expand Up @@ -1987,6 +1987,12 @@ Set to attempt to recover from fatal errors.
This should only be used as a last resort,
as it typically results in leaked space, or worse.
.
.It Sy zfs_recover_rt Ns = Ns Sy 0 Ns | Ns 1 Pq int
Set to attempt to recover from fatal errors while adding or removing
unexpected segments to a range tree.
This should only be used as a last resort,
as it typically results in leaked space.
.
.It Sy zfs_removal_ignore_errors Ns = Ns Sy 0 Ns | Ns 1 Pq int
Ignore hard I/O errors during device removal.
When set, if a device encounters a hard I/O error during the removal process
Expand Down
6 changes: 4 additions & 2 deletions module/zfs/dnode.c
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Expand Up @@ -2435,8 +2435,10 @@ dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
{
int txgoff = tx->tx_txg & TXG_MASK;
if (dn->dn_free_ranges[txgoff] == NULL) {
dn->dn_free_ranges[txgoff] = zfs_range_tree_create(NULL,
ZFS_RANGE_SEG64, NULL, 0, 0);
dn->dn_free_ranges[txgoff] =
zfs_range_tree_create_flags(
NULL, ZFS_RANGE_SEG64, NULL, 0, 0,
ZFS_RANGE_TREE_F_UC_FREE_SPACE, "dn_free_ranges");
}
zfs_range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks);
zfs_range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks);
Expand Down
73 changes: 55 additions & 18 deletions module/zfs/metaslab.c
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Expand Up @@ -368,6 +368,17 @@ static metaslab_stats_t metaslab_stats = {
#define METASLABSTAT_BUMP(stat) \
atomic_inc_64(&metaslab_stats.stat.value.ui64);

static inline char *
zfs_rt_name(metaslab_group_t *mg, metaslab_t *ms,
const char *name)
{
return (kmem_asprintf("{spa=%s vdev_guid=%llu ms_id=%llu %s}",
mg->mg_vd->vdev_spa->spa_name,
(u_longlong_t)mg->mg_vd->vdev_guid,
(u_longlong_t)ms->ms_id,
name));
}


static kstat_t *metaslab_ksp;

Expand Down Expand Up @@ -2753,30 +2764,53 @@ metaslab_init(metaslab_group_t *mg, uint64_t id, uint64_t object,
zfs_range_seg_type_t type =
metaslab_calculate_range_tree_type(vd, ms, &start, &shift);

ms->ms_allocatable = zfs_range_tree_create(NULL, type, NULL, start,
shift);
ms->ms_allocatable = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_allocatable"));
for (int t = 0; t < TXG_SIZE; t++) {
ms->ms_allocating[t] = zfs_range_tree_create(NULL, type,
NULL, start, shift);
}
ms->ms_freeing = zfs_range_tree_create(NULL, type, NULL, start, shift);
ms->ms_freed = zfs_range_tree_create(NULL, type, NULL, start, shift);
ms->ms_allocating[t] = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_ALLOCATED_SPACE |
ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_allocating"));
}
ms->ms_freeing = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_freeing"));
ms->ms_freed = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_freed"));
for (int t = 0; t < TXG_DEFER_SIZE; t++) {
ms->ms_defer[t] = zfs_range_tree_create(NULL, type, NULL,
start, shift);
}
ms->ms_checkpointing =
zfs_range_tree_create(NULL, type, NULL, start, shift);
ms->ms_unflushed_allocs =
zfs_range_tree_create(NULL, type, NULL, start, shift);
ms->ms_defer[t] = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE |
ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_defer"));
}
ms->ms_checkpointing = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_checkpointing"));
ms->ms_unflushed_allocs = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_ALLOCATED_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_unflushed_allocs"));

metaslab_rt_arg_t *mrap = kmem_zalloc(sizeof (*mrap), KM_SLEEP);
mrap->mra_bt = &ms->ms_unflushed_frees_by_size;
mrap->mra_floor_shift = metaslab_by_size_min_shift;
ms->ms_unflushed_frees = zfs_range_tree_create(&metaslab_rt_ops,
type, mrap, start, shift);
ms->ms_unflushed_frees = zfs_range_tree_create_flags(
&metaslab_rt_ops, type, mrap, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_unflushed_frees"));

ms->ms_trim = zfs_range_tree_create(NULL, type, NULL, start, shift);
ms->ms_trim = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(mg, ms, "ms_trim"));

metaslab_group_add(mg, ms);
metaslab_set_fragmentation(ms, B_FALSE);
Expand Down Expand Up @@ -3750,7 +3784,10 @@ metaslab_condense(metaslab_t *msp, dmu_tx_t *tx)
type = metaslab_calculate_range_tree_type(msp->ms_group->mg_vd, msp,
&start, &shift);

condense_tree = zfs_range_tree_create(NULL, type, NULL, start, shift);
condense_tree = zfs_range_tree_create_flags(
NULL, type, NULL, start, shift,
ZFS_RANGE_TREE_F_UC_FREE_SPACE | ZFS_RANGE_TREE_F_DYN_NAME,
zfs_rt_name(msp->ms_group, msp, "condense_tree"));

for (int t = 0; t < TXG_DEFER_SIZE; t++) {
zfs_range_tree_walk(msp->ms_defer[t],
Expand Down
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