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kernel-fxtec-pro1x/drivers/md/dm-thin-metadata.c
Mike Snitzer 07f2b6e038 dm thin: ensure user takes action to validate data and metadata consistency 
If a thin metadata operation fails the current transaction will abort,
whereby causing potential for IO layers up the stack (e.g. filesystems)
to have data loss.  As such, set THIN_METADATA_NEEDS_CHECK_FLAG in the
thin metadata's superblock which:
1) requires the user verify the thin metadata is consistent (e.g. use
   thin_check, etc)
2) suggests the user verify the thin data is consistent (e.g. use fsck)

The only way to clear the superblock's THIN_METADATA_NEEDS_CHECK_FLAG is
to run thin_repair.

On metadata operation failure: abort current metadata transaction, set
pool in read-only mode, and now set the needs_check flag.

As part of this change, constraints are introduced or relaxed:
* don't allow a pool to transition to write mode if needs_check is set
* don't allow data or metadata space to be resized if needs_check is set
* if a thin pool's metadata space is exhausted: the kernel will now
  force the user to take the pool offline for repair before the kernel
  will allow the metadata space to be extended.

Also, update Documentation to include information about when the thin
provisioning target commits metadata, how it handles metadata failures
and running out of space.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
2014-03-05 15:25:35 -05:00

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/*
* Copyright (C) 2011-2012 Red Hat, Inc.
*
* This file is released under the GPL.
*/
#include "dm-thin-metadata.h"
#include "persistent-data/dm-btree.h"
#include "persistent-data/dm-space-map.h"
#include "persistent-data/dm-space-map-disk.h"
#include "persistent-data/dm-transaction-manager.h"
#include <linux/list.h>
#include <linux/device-mapper.h>
#include <linux/workqueue.h>
/*--------------------------------------------------------------------------
* As far as the metadata goes, there is:
*
* - A superblock in block zero, taking up fewer than 512 bytes for
* atomic writes.
*
* - A space map managing the metadata blocks.
*
* - A space map managing the data blocks.
*
* - A btree mapping our internal thin dev ids onto struct disk_device_details.
*
* - A hierarchical btree, with 2 levels which effectively maps (thin
* dev id, virtual block) -> block_time. Block time is a 64-bit
* field holding the time in the low 24 bits, and block in the top 48
* bits.
*
* BTrees consist solely of btree_nodes, that fill a block. Some are
* internal nodes, as such their values are a __le64 pointing to other
* nodes. Leaf nodes can store data of any reasonable size (ie. much
* smaller than the block size). The nodes consist of the header,
* followed by an array of keys, followed by an array of values. We have
* to binary search on the keys so they're all held together to help the
* cpu cache.
*
* Space maps have 2 btrees:
*
* - One maps a uint64_t onto a struct index_entry. Which points to a
* bitmap block, and has some details about how many free entries there
* are etc.
*
* - The bitmap blocks have a header (for the checksum). Then the rest
* of the block is pairs of bits. With the meaning being:
*
* 0 - ref count is 0
* 1 - ref count is 1
* 2 - ref count is 2
* 3 - ref count is higher than 2
*
* - If the count is higher than 2 then the ref count is entered in a
* second btree that directly maps the block_address to a uint32_t ref
* count.
*
* The space map metadata variant doesn't have a bitmaps btree. Instead
* it has one single blocks worth of index_entries. This avoids
* recursive issues with the bitmap btree needing to allocate space in
* order to insert. With a small data block size such as 64k the
* metadata support data devices that are hundreds of terrabytes.
*
* The space maps allocate space linearly from front to back. Space that
* is freed in a transaction is never recycled within that transaction.
* To try and avoid fragmenting _free_ space the allocator always goes
* back and fills in gaps.
*
* All metadata io is in THIN_METADATA_BLOCK_SIZE sized/aligned chunks
* from the block manager.
*--------------------------------------------------------------------------*/
#define DM_MSG_PREFIX "thin metadata"
#define THIN_SUPERBLOCK_MAGIC 27022010
#define THIN_SUPERBLOCK_LOCATION 0
#define THIN_VERSION 2
#define THIN_METADATA_CACHE_SIZE 64
#define SECTOR_TO_BLOCK_SHIFT 3
/*
* 3 for btree insert +
* 2 for btree lookup used within space map
*/
#define THIN_MAX_CONCURRENT_LOCKS 5
/* This should be plenty */
#define SPACE_MAP_ROOT_SIZE 128
/*
* Little endian on-disk superblock and device details.
*/
struct thin_disk_superblock {
__le32 csum; /* Checksum of superblock except for this field. */
__le32 flags;
__le64 blocknr; /* This block number, dm_block_t. */
__u8 uuid[16];
__le64 magic;
__le32 version;
__le32 time;
__le64 trans_id;
/*
* Root held by userspace transactions.
*/
__le64 held_root;
__u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
/*
* 2-level btree mapping (dev_id, (dev block, time)) -> data block
*/
__le64 data_mapping_root;
/*
* Device detail root mapping dev_id -> device_details
*/
__le64 device_details_root;
__le32 data_block_size; /* In 512-byte sectors. */
__le32 metadata_block_size; /* In 512-byte sectors. */
__le64 metadata_nr_blocks;
__le32 compat_flags;
__le32 compat_ro_flags;
__le32 incompat_flags;
} __packed;
struct disk_device_details {
__le64 mapped_blocks;
__le64 transaction_id; /* When created. */
__le32 creation_time;
__le32 snapshotted_time;
} __packed;
struct dm_pool_metadata {
struct hlist_node hash;
struct block_device *bdev;
struct dm_block_manager *bm;
struct dm_space_map *metadata_sm;
struct dm_space_map *data_sm;
struct dm_transaction_manager *tm;
struct dm_transaction_manager *nb_tm;
/*
* Two-level btree.
* First level holds thin_dev_t.
* Second level holds mappings.
*/
struct dm_btree_info info;
/*
* Non-blocking version of the above.
*/
struct dm_btree_info nb_info;
/*
* Just the top level for deleting whole devices.
*/
struct dm_btree_info tl_info;
/*
* Just the bottom level for creating new devices.
*/
struct dm_btree_info bl_info;
/*
* Describes the device details btree.
*/
struct dm_btree_info details_info;
struct rw_semaphore root_lock;
uint32_t time;
dm_block_t root;
dm_block_t details_root;
struct list_head thin_devices;
uint64_t trans_id;
unsigned long flags;
sector_t data_block_size;
bool read_only:1;
/*
* Set if a transaction has to be aborted but the attempt to roll back
* to the previous (good) transaction failed. The only pool metadata
* operation possible in this state is the closing of the device.
*/
bool fail_io:1;
};
struct dm_thin_device {
struct list_head list;
struct dm_pool_metadata *pmd;
dm_thin_id id;
int open_count;
bool changed:1;
bool aborted_with_changes:1;
uint64_t mapped_blocks;
uint64_t transaction_id;
uint32_t creation_time;
uint32_t snapshotted_time;
};
/*----------------------------------------------------------------
* superblock validator
*--------------------------------------------------------------*/
#define SUPERBLOCK_CSUM_XOR 160774
static void sb_prepare_for_write(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size)
{
struct thin_disk_superblock *disk_super = dm_block_data(b);
disk_super->blocknr = cpu_to_le64(dm_block_location(b));
disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR));
}
static int sb_check(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size)
{
struct thin_disk_superblock *disk_super = dm_block_data(b);
__le32 csum_le;
if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
DMERR("sb_check failed: blocknr %llu: "
"wanted %llu", le64_to_cpu(disk_super->blocknr),
(unsigned long long)dm_block_location(b));
return -ENOTBLK;
}
if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) {
DMERR("sb_check failed: magic %llu: "
"wanted %llu", le64_to_cpu(disk_super->magic),
(unsigned long long)THIN_SUPERBLOCK_MAGIC);
return -EILSEQ;
}
csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR));
if (csum_le != disk_super->csum) {
DMERR("sb_check failed: csum %u: wanted %u",
le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
return -EILSEQ;
}
return 0;
}
static struct dm_block_validator sb_validator = {
.name = "superblock",
.prepare_for_write = sb_prepare_for_write,
.check = sb_check
};
/*----------------------------------------------------------------
* Methods for the btree value types
*--------------------------------------------------------------*/
static uint64_t pack_block_time(dm_block_t b, uint32_t t)
{
return (b << 24) | t;
}
static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
{
*b = v >> 24;
*t = v & ((1 << 24) - 1);
}
static void data_block_inc(void *context, const void *value_le)
{
struct dm_space_map *sm = context;
__le64 v_le;
uint64_t b;
uint32_t t;
memcpy(&v_le, value_le, sizeof(v_le));
unpack_block_time(le64_to_cpu(v_le), &b, &t);
dm_sm_inc_block(sm, b);
}
static void data_block_dec(void *context, const void *value_le)
{
struct dm_space_map *sm = context;
__le64 v_le;
uint64_t b;
uint32_t t;
memcpy(&v_le, value_le, sizeof(v_le));
unpack_block_time(le64_to_cpu(v_le), &b, &t);
dm_sm_dec_block(sm, b);
}
static int data_block_equal(void *context, const void *value1_le, const void *value2_le)
{
__le64 v1_le, v2_le;
uint64_t b1, b2;
uint32_t t;
memcpy(&v1_le, value1_le, sizeof(v1_le));
memcpy(&v2_le, value2_le, sizeof(v2_le));
unpack_block_time(le64_to_cpu(v1_le), &b1, &t);
unpack_block_time(le64_to_cpu(v2_le), &b2, &t);
return b1 == b2;
}
static void subtree_inc(void *context, const void *value)
{
struct dm_btree_info *info = context;
__le64 root_le;
uint64_t root;
memcpy(&root_le, value, sizeof(root_le));
root = le64_to_cpu(root_le);
dm_tm_inc(info->tm, root);
}
static void subtree_dec(void *context, const void *value)
{
struct dm_btree_info *info = context;
__le64 root_le;
uint64_t root;
memcpy(&root_le, value, sizeof(root_le));
root = le64_to_cpu(root_le);
if (dm_btree_del(info, root))
DMERR("btree delete failed\n");
}
static int subtree_equal(void *context, const void *value1_le, const void *value2_le)
{
__le64 v1_le, v2_le;
memcpy(&v1_le, value1_le, sizeof(v1_le));
memcpy(&v2_le, value2_le, sizeof(v2_le));
return v1_le == v2_le;
}
/*----------------------------------------------------------------*/
static int superblock_lock_zero(struct dm_pool_metadata *pmd,
struct dm_block **sblock)
{
return dm_bm_write_lock_zero(pmd->bm, THIN_SUPERBLOCK_LOCATION,
&sb_validator, sblock);
}
static int superblock_lock(struct dm_pool_metadata *pmd,
struct dm_block **sblock)
{
return dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
&sb_validator, sblock);
}
static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result)
{
int r;
unsigned i;
struct dm_block *b;
__le64 *data_le, zero = cpu_to_le64(0);
unsigned block_size = dm_bm_block_size(bm) / sizeof(__le64);
/*
* We can't use a validator here - it may be all zeroes.
*/
r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, NULL, &b);
if (r)
return r;
data_le = dm_block_data(b);
*result = 1;
for (i = 0; i < block_size; i++) {
if (data_le[i] != zero) {
*result = 0;
break;
}
}
return dm_bm_unlock(b);
}
static void __setup_btree_details(struct dm_pool_metadata *pmd)
{
pmd->info.tm = pmd->tm;
pmd->info.levels = 2;
pmd->info.value_type.context = pmd->data_sm;
pmd->info.value_type.size = sizeof(__le64);
pmd->info.value_type.inc = data_block_inc;
pmd->info.value_type.dec = data_block_dec;
pmd->info.value_type.equal = data_block_equal;
memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info));
pmd->nb_info.tm = pmd->nb_tm;
pmd->tl_info.tm = pmd->tm;
pmd->tl_info.levels = 1;
pmd->tl_info.value_type.context = &pmd->bl_info;
pmd->tl_info.value_type.size = sizeof(__le64);
pmd->tl_info.value_type.inc = subtree_inc;
pmd->tl_info.value_type.dec = subtree_dec;
pmd->tl_info.value_type.equal = subtree_equal;
pmd->bl_info.tm = pmd->tm;
pmd->bl_info.levels = 1;
pmd->bl_info.value_type.context = pmd->data_sm;
pmd->bl_info.value_type.size = sizeof(__le64);
pmd->bl_info.value_type.inc = data_block_inc;
pmd->bl_info.value_type.dec = data_block_dec;
pmd->bl_info.value_type.equal = data_block_equal;
pmd->details_info.tm = pmd->tm;
pmd->details_info.levels = 1;
pmd->details_info.value_type.context = NULL;
pmd->details_info.value_type.size = sizeof(struct disk_device_details);
pmd->details_info.value_type.inc = NULL;
pmd->details_info.value_type.dec = NULL;
pmd->details_info.value_type.equal = NULL;
}
static int __write_initial_superblock(struct dm_pool_metadata *pmd)
{
int r;
struct dm_block *sblock;
size_t metadata_len, data_len;
struct thin_disk_superblock *disk_super;
sector_t bdev_size = i_size_read(pmd->bdev->bd_inode) >> SECTOR_SHIFT;
if (bdev_size > THIN_METADATA_MAX_SECTORS)
bdev_size = THIN_METADATA_MAX_SECTORS;
r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
if (r < 0)
return r;
r = dm_sm_root_size(pmd->data_sm, &data_len);
if (r < 0)
return r;
r = dm_sm_commit(pmd->data_sm);
if (r < 0)
return r;
r = dm_tm_pre_commit(pmd->tm);
if (r < 0)
return r;
r = superblock_lock_zero(pmd, &sblock);
if (r)
return r;
disk_super = dm_block_data(sblock);
disk_super->flags = 0;
memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC);
disk_super->version = cpu_to_le32(THIN_VERSION);
disk_super->time = 0;
disk_super->trans_id = 0;
disk_super->held_root = 0;
r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
metadata_len);
if (r < 0)
goto bad_locked;
r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
data_len);
if (r < 0)
goto bad_locked;
disk_super->data_mapping_root = cpu_to_le64(pmd->root);
disk_super->device_details_root = cpu_to_le64(pmd->details_root);
disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE);
disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT);
disk_super->data_block_size = cpu_to_le32(pmd->data_block_size);
return dm_tm_commit(pmd->tm, sblock);
bad_locked:
dm_bm_unlock(sblock);
return r;
}
static int __format_metadata(struct dm_pool_metadata *pmd)
{
int r;
r = dm_tm_create_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
&pmd->tm, &pmd->metadata_sm);
if (r < 0) {
DMERR("tm_create_with_sm failed");
return r;
}
pmd->data_sm = dm_sm_disk_create(pmd->tm, 0);
if (IS_ERR(pmd->data_sm)) {
DMERR("sm_disk_create failed");
r = PTR_ERR(pmd->data_sm);
goto bad_cleanup_tm;
}
pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
if (!pmd->nb_tm) {
DMERR("could not create non-blocking clone tm");
r = -ENOMEM;
goto bad_cleanup_data_sm;
}
__setup_btree_details(pmd);
r = dm_btree_empty(&pmd->info, &pmd->root);
if (r < 0)
goto bad_cleanup_nb_tm;
r = dm_btree_empty(&pmd->details_info, &pmd->details_root);
if (r < 0) {
DMERR("couldn't create devices root");
goto bad_cleanup_nb_tm;
}
r = __write_initial_superblock(pmd);
if (r)
goto bad_cleanup_nb_tm;
return 0;
bad_cleanup_nb_tm:
dm_tm_destroy(pmd->nb_tm);
bad_cleanup_data_sm:
dm_sm_destroy(pmd->data_sm);
bad_cleanup_tm:
dm_tm_destroy(pmd->tm);
dm_sm_destroy(pmd->metadata_sm);
return r;
}
static int __check_incompat_features(struct thin_disk_superblock *disk_super,
struct dm_pool_metadata *pmd)
{
uint32_t features;
features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP;
if (features) {
DMERR("could not access metadata due to unsupported optional features (%lx).",
(unsigned long)features);
return -EINVAL;
}
/*
* Check for read-only metadata to skip the following RDWR checks.
*/
if (get_disk_ro(pmd->bdev->bd_disk))
return 0;
features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP;
if (features) {
DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
(unsigned long)features);
return -EINVAL;
}
return 0;
}
static int __open_metadata(struct dm_pool_metadata *pmd)
{
int r;
struct dm_block *sblock;
struct thin_disk_superblock *disk_super;
r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
&sb_validator, &sblock);
if (r < 0) {
DMERR("couldn't read superblock");
return r;
}
disk_super = dm_block_data(sblock);
r = __check_incompat_features(disk_super, pmd);
if (r < 0)
goto bad_unlock_sblock;
r = dm_tm_open_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
disk_super->metadata_space_map_root,
sizeof(disk_super->metadata_space_map_root),
&pmd->tm, &pmd->metadata_sm);
if (r < 0) {
DMERR("tm_open_with_sm failed");
goto bad_unlock_sblock;
}
pmd->data_sm = dm_sm_disk_open(pmd->tm, disk_super->data_space_map_root,
sizeof(disk_super->data_space_map_root));
if (IS_ERR(pmd->data_sm)) {
DMERR("sm_disk_open failed");
r = PTR_ERR(pmd->data_sm);
goto bad_cleanup_tm;
}
pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
if (!pmd->nb_tm) {
DMERR("could not create non-blocking clone tm");
r = -ENOMEM;
goto bad_cleanup_data_sm;
}
__setup_btree_details(pmd);
return dm_bm_unlock(sblock);
bad_cleanup_data_sm:
dm_sm_destroy(pmd->data_sm);
bad_cleanup_tm:
dm_tm_destroy(pmd->tm);
dm_sm_destroy(pmd->metadata_sm);
bad_unlock_sblock:
dm_bm_unlock(sblock);
return r;
}
static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device)
{
int r, unformatted;
r = __superblock_all_zeroes(pmd->bm, &unformatted);
if (r)
return r;
if (unformatted)
return format_device ? __format_metadata(pmd) : -EPERM;
return __open_metadata(pmd);
}
static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device)
{
int r;
pmd->bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
THIN_METADATA_CACHE_SIZE,
THIN_MAX_CONCURRENT_LOCKS);
if (IS_ERR(pmd->bm)) {
DMERR("could not create block manager");
return PTR_ERR(pmd->bm);
}
r = __open_or_format_metadata(pmd, format_device);
if (r)
dm_block_manager_destroy(pmd->bm);
return r;
}
static void __destroy_persistent_data_objects(struct dm_pool_metadata *pmd)
{
dm_sm_destroy(pmd->data_sm);
dm_sm_destroy(pmd->metadata_sm);
dm_tm_destroy(pmd->nb_tm);
dm_tm_destroy(pmd->tm);
dm_block_manager_destroy(pmd->bm);
}
static int __begin_transaction(struct dm_pool_metadata *pmd)
{
int r;
struct thin_disk_superblock *disk_super;
struct dm_block *sblock;
/*
* We re-read the superblock every time. Shouldn't need to do this
* really.
*/
r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
&sb_validator, &sblock);
if (r)
return r;
disk_super = dm_block_data(sblock);
pmd->time = le32_to_cpu(disk_super->time);
pmd->root = le64_to_cpu(disk_super->data_mapping_root);
pmd->details_root = le64_to_cpu(disk_super->device_details_root);
pmd->trans_id = le64_to_cpu(disk_super->trans_id);
pmd->flags = le32_to_cpu(disk_super->flags);
pmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
dm_bm_unlock(sblock);
return 0;
}
static int __write_changed_details(struct dm_pool_metadata *pmd)
{
int r;
struct dm_thin_device *td, *tmp;
struct disk_device_details details;
uint64_t key;
list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
if (!td->changed)
continue;
key = td->id;
details.mapped_blocks = cpu_to_le64(td->mapped_blocks);
details.transaction_id = cpu_to_le64(td->transaction_id);
details.creation_time = cpu_to_le32(td->creation_time);
details.snapshotted_time = cpu_to_le32(td->snapshotted_time);
__dm_bless_for_disk(&details);
r = dm_btree_insert(&pmd->details_info, pmd->details_root,
&key, &details, &pmd->details_root);
if (r)
return r;
if (td->open_count)
td->changed = 0;
else {
list_del(&td->list);
kfree(td);
}
}
return 0;
}
static int __commit_transaction(struct dm_pool_metadata *pmd)
{
int r;
size_t metadata_len, data_len;
struct thin_disk_superblock *disk_super;
struct dm_block *sblock;
/*
* We need to know if the thin_disk_superblock exceeds a 512-byte sector.
*/
BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
r = __write_changed_details(pmd);
if (r < 0)
return r;
r = dm_sm_commit(pmd->data_sm);
if (r < 0)
return r;
r = dm_tm_pre_commit(pmd->tm);
if (r < 0)
return r;
r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
if (r < 0)
return r;
r = dm_sm_root_size(pmd->data_sm, &data_len);
if (r < 0)
return r;
r = superblock_lock(pmd, &sblock);
if (r)
return r;
disk_super = dm_block_data(sblock);
disk_super->time = cpu_to_le32(pmd->time);
disk_super->data_mapping_root = cpu_to_le64(pmd->root);
disk_super->device_details_root = cpu_to_le64(pmd->details_root);
disk_super->trans_id = cpu_to_le64(pmd->trans_id);
disk_super->flags = cpu_to_le32(pmd->flags);
r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
metadata_len);
if (r < 0)
goto out_locked;
r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
data_len);
if (r < 0)
goto out_locked;
return dm_tm_commit(pmd->tm, sblock);
out_locked:
dm_bm_unlock(sblock);
return r;
}
struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
sector_t data_block_size,
bool format_device)
{
int r;
struct dm_pool_metadata *pmd;
pmd = kmalloc(sizeof(*pmd), GFP_KERNEL);
if (!pmd) {
DMERR("could not allocate metadata struct");
return ERR_PTR(-ENOMEM);
}
init_rwsem(&pmd->root_lock);
pmd->time = 0;
INIT_LIST_HEAD(&pmd->thin_devices);
pmd->read_only = false;
pmd->fail_io = false;
pmd->bdev = bdev;
pmd->data_block_size = data_block_size;
r = __create_persistent_data_objects(pmd, format_device);
if (r) {
kfree(pmd);
return ERR_PTR(r);
}
r = __begin_transaction(pmd);
if (r < 0) {
if (dm_pool_metadata_close(pmd) < 0)
DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
return ERR_PTR(r);
}
return pmd;
}
int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
{
int r;
unsigned open_devices = 0;
struct dm_thin_device *td, *tmp;
down_read(&pmd->root_lock);
list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
if (td->open_count)
open_devices++;
else {
list_del(&td->list);
kfree(td);
}
}
up_read(&pmd->root_lock);
if (open_devices) {
DMERR("attempt to close pmd when %u device(s) are still open",
open_devices);
return -EBUSY;
}
if (!pmd->read_only && !pmd->fail_io) {
r = __commit_transaction(pmd);
if (r < 0)
DMWARN("%s: __commit_transaction() failed, error = %d",
__func__, r);
}
if (!pmd->fail_io)
__destroy_persistent_data_objects(pmd);
kfree(pmd);
return 0;
}
/*
* __open_device: Returns @td corresponding to device with id @dev,
* creating it if @create is set and incrementing @td->open_count.
* On failure, @td is undefined.
*/
static int __open_device(struct dm_pool_metadata *pmd,
dm_thin_id dev, int create,
struct dm_thin_device **td)
{
int r, changed = 0;
struct dm_thin_device *td2;
uint64_t key = dev;
struct disk_device_details details_le;
/*
* If the device is already open, return it.
*/
list_for_each_entry(td2, &pmd->thin_devices, list)
if (td2->id == dev) {
/*
* May not create an already-open device.
*/
if (create)
return -EEXIST;
td2->open_count++;
*td = td2;
return 0;
}
/*
* Check the device exists.
*/
r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
&key, &details_le);
if (r) {
if (r != -ENODATA || !create)
return r;
/*
* Create new device.
*/
changed = 1;
details_le.mapped_blocks = 0;
details_le.transaction_id = cpu_to_le64(pmd->trans_id);
details_le.creation_time = cpu_to_le32(pmd->time);
details_le.snapshotted_time = cpu_to_le32(pmd->time);
}
*td = kmalloc(sizeof(**td), GFP_NOIO);
if (!*td)
return -ENOMEM;
(*td)->pmd = pmd;
(*td)->id = dev;
(*td)->open_count = 1;
(*td)->changed = changed;
(*td)->aborted_with_changes = false;
(*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks);
(*td)->transaction_id = le64_to_cpu(details_le.transaction_id);
(*td)->creation_time = le32_to_cpu(details_le.creation_time);
(*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time);
list_add(&(*td)->list, &pmd->thin_devices);
return 0;
}
static void __close_device(struct dm_thin_device *td)
{
--td->open_count;
}
static int __create_thin(struct dm_pool_metadata *pmd,
dm_thin_id dev)
{
int r;
dm_block_t dev_root;
uint64_t key = dev;
struct disk_device_details details_le;
struct dm_thin_device *td;
__le64 value;
r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
&key, &details_le);
if (!r)
return -EEXIST;
/*
* Create an empty btree for the mappings.
*/
r = dm_btree_empty(&pmd->bl_info, &dev_root);
if (r)
return r;
/*
* Insert it into the main mapping tree.
*/
value = cpu_to_le64(dev_root);
__dm_bless_for_disk(&value);
r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
if (r) {
dm_btree_del(&pmd->bl_info, dev_root);
return r;
}
r = __open_device(pmd, dev, 1, &td);
if (r) {
dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
dm_btree_del(&pmd->bl_info, dev_root);
return r;
}
__close_device(td);
return r;
}
int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __create_thin(pmd, dev);
up_write(&pmd->root_lock);
return r;
}
static int __set_snapshot_details(struct dm_pool_metadata *pmd,
struct dm_thin_device *snap,
dm_thin_id origin, uint32_t time)
{
int r;
struct dm_thin_device *td;
r = __open_device(pmd, origin, 0, &td);
if (r)
return r;
td->changed = 1;
td->snapshotted_time = time;
snap->mapped_blocks = td->mapped_blocks;
snap->snapshotted_time = time;
__close_device(td);
return 0;
}
static int __create_snap(struct dm_pool_metadata *pmd,
dm_thin_id dev, dm_thin_id origin)
{
int r;
dm_block_t origin_root;
uint64_t key = origin, dev_key = dev;
struct dm_thin_device *td;
struct disk_device_details details_le;
__le64 value;
/* check this device is unused */
r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
&dev_key, &details_le);
if (!r)
return -EEXIST;
/* find the mapping tree for the origin */
r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value);
if (r)
return r;
origin_root = le64_to_cpu(value);
/* clone the origin, an inc will do */
dm_tm_inc(pmd->tm, origin_root);
/* insert into the main mapping tree */
value = cpu_to_le64(origin_root);
__dm_bless_for_disk(&value);
key = dev;
r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
if (r) {
dm_tm_dec(pmd->tm, origin_root);
return r;
}
pmd->time++;
r = __open_device(pmd, dev, 1, &td);
if (r)
goto bad;
r = __set_snapshot_details(pmd, td, origin, pmd->time);
__close_device(td);
if (r)
goto bad;
return 0;
bad:
dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
dm_btree_remove(&pmd->details_info, pmd->details_root,
&key, &pmd->details_root);
return r;
}
int dm_pool_create_snap(struct dm_pool_metadata *pmd,
dm_thin_id dev,
dm_thin_id origin)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __create_snap(pmd, dev, origin);
up_write(&pmd->root_lock);
return r;
}
static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev)
{
int r;
uint64_t key = dev;
struct dm_thin_device *td;
/* TODO: failure should mark the transaction invalid */
r = __open_device(pmd, dev, 0, &td);
if (r)
return r;
if (td->open_count > 1) {
__close_device(td);
return -EBUSY;
}
list_del(&td->list);
kfree(td);
r = dm_btree_remove(&pmd->details_info, pmd->details_root,
&key, &pmd->details_root);
if (r)
return r;
r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
if (r)
return r;
return 0;
}
int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
dm_thin_id dev)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __delete_device(pmd, dev);
up_write(&pmd->root_lock);
return r;
}
int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
uint64_t current_id,
uint64_t new_id)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (pmd->fail_io)
goto out;
if (pmd->trans_id != current_id) {
DMERR("mismatched transaction id");
goto out;
}
pmd->trans_id = new_id;
r = 0;
out:
up_write(&pmd->root_lock);
return r;
}
int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
uint64_t *result)
{
int r = -EINVAL;
down_read(&pmd->root_lock);
if (!pmd->fail_io) {
*result = pmd->trans_id;
r = 0;
}
up_read(&pmd->root_lock);
return r;
}
static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
{
int r, inc;
struct thin_disk_superblock *disk_super;
struct dm_block *copy, *sblock;
dm_block_t held_root;
/*
* Copy the superblock.
*/
dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
&sb_validator, &copy, &inc);
if (r)
return r;
BUG_ON(!inc);
held_root = dm_block_location(copy);
disk_super = dm_block_data(copy);
if (le64_to_cpu(disk_super->held_root)) {
DMWARN("Pool metadata snapshot already exists: release this before taking another.");
dm_tm_dec(pmd->tm, held_root);
dm_tm_unlock(pmd->tm, copy);
return -EBUSY;
}
/*
* Wipe the spacemap since we're not publishing this.
*/
memset(&disk_super->data_space_map_root, 0,
sizeof(disk_super->data_space_map_root));
memset(&disk_super->metadata_space_map_root, 0,
sizeof(disk_super->metadata_space_map_root));
/*
* Increment the data structures that need to be preserved.
*/
dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
dm_tm_unlock(pmd->tm, copy);
/*
* Write the held root into the superblock.
*/
r = superblock_lock(pmd, &sblock);
if (r) {
dm_tm_dec(pmd->tm, held_root);
return r;
}
disk_super = dm_block_data(sblock);
disk_super->held_root = cpu_to_le64(held_root);
dm_bm_unlock(sblock);
return 0;
}
int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __reserve_metadata_snap(pmd);
up_write(&pmd->root_lock);
return r;
}
static int __release_metadata_snap(struct dm_pool_metadata *pmd)
{
int r;
struct thin_disk_superblock *disk_super;
struct dm_block *sblock, *copy;
dm_block_t held_root;
r = superblock_lock(pmd, &sblock);
if (r)
return r;
disk_super = dm_block_data(sblock);
held_root = le64_to_cpu(disk_super->held_root);
disk_super->held_root = cpu_to_le64(0);
dm_bm_unlock(sblock);
if (!held_root) {
DMWARN("No pool metadata snapshot found: nothing to release.");
return -EINVAL;
}
r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
if (r)
return r;
disk_super = dm_block_data(copy);
dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->data_mapping_root));
dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->device_details_root));
dm_sm_dec_block(pmd->metadata_sm, held_root);
return dm_tm_unlock(pmd->tm, copy);
}
int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __release_metadata_snap(pmd);
up_write(&pmd->root_lock);
return r;
}
static int __get_metadata_snap(struct dm_pool_metadata *pmd,
dm_block_t *result)
{
int r;
struct thin_disk_superblock *disk_super;
struct dm_block *sblock;
r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
&sb_validator, &sblock);
if (r)
return r;
disk_super = dm_block_data(sblock);
*result = le64_to_cpu(disk_super->held_root);
return dm_bm_unlock(sblock);
}
int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
dm_block_t *result)
{
int r = -EINVAL;
down_read(&pmd->root_lock);
if (!pmd->fail_io)
r = __get_metadata_snap(pmd, result);
up_read(&pmd->root_lock);
return r;
}
int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
struct dm_thin_device **td)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __open_device(pmd, dev, 0, td);
up_write(&pmd->root_lock);
return r;
}
int dm_pool_close_thin_device(struct dm_thin_device *td)
{
down_write(&td->pmd->root_lock);
__close_device(td);
up_write(&td->pmd->root_lock);
return 0;
}
dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
{
return td->id;
}
/*
* Check whether @time (of block creation) is older than @td's last snapshot.
* If so then the associated block is shared with the last snapshot device.
* Any block on a device created *after* the device last got snapshotted is
* necessarily not shared.
*/
static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
{
return td->snapshotted_time > time;
}
int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
int can_block, struct dm_thin_lookup_result *result)
{
int r = -EINVAL;
uint64_t block_time = 0;
__le64 value;
struct dm_pool_metadata *pmd = td->pmd;
dm_block_t keys[2] = { td->id, block };
struct dm_btree_info *info;
if (can_block) {
down_read(&pmd->root_lock);
info = &pmd->info;
} else if (down_read_trylock(&pmd->root_lock))
info = &pmd->nb_info;
else
return -EWOULDBLOCK;
if (pmd->fail_io)
goto out;
r = dm_btree_lookup(info, pmd->root, keys, &value);
if (!r)
block_time = le64_to_cpu(value);
out:
up_read(&pmd->root_lock);
if (!r) {
dm_block_t exception_block;
uint32_t exception_time;
unpack_block_time(block_time, &exception_block,
&exception_time);
result->block = exception_block;
result->shared = __snapshotted_since(td, exception_time);
}
return r;
}
static int __insert(struct dm_thin_device *td, dm_block_t block,
dm_block_t data_block)
{
int r, inserted;
__le64 value;
struct dm_pool_metadata *pmd = td->pmd;
dm_block_t keys[2] = { td->id, block };
value = cpu_to_le64(pack_block_time(data_block, pmd->time));
__dm_bless_for_disk(&value);
r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
&pmd->root, &inserted);
if (r)
return r;
td->changed = 1;
if (inserted)
td->mapped_blocks++;
return 0;
}
int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
dm_block_t data_block)
{
int r = -EINVAL;
down_write(&td->pmd->root_lock);
if (!td->pmd->fail_io)
r = __insert(td, block, data_block);
up_write(&td->pmd->root_lock);
return r;
}
static int __remove(struct dm_thin_device *td, dm_block_t block)
{
int r;
struct dm_pool_metadata *pmd = td->pmd;
dm_block_t keys[2] = { td->id, block };
r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
if (r)
return r;
td->mapped_blocks--;
td->changed = 1;
return 0;
}
int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
{
int r = -EINVAL;
down_write(&td->pmd->root_lock);
if (!td->pmd->fail_io)
r = __remove(td, block);
up_write(&td->pmd->root_lock);
return r;
}
int dm_pool_block_is_used(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
{
int r;
uint32_t ref_count;
down_read(&pmd->root_lock);
r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
if (!r)
*result = (ref_count != 0);
up_read(&pmd->root_lock);
return r;
}
bool dm_thin_changed_this_transaction(struct dm_thin_device *td)
{
int r;
down_read(&td->pmd->root_lock);
r = td->changed;
up_read(&td->pmd->root_lock);
return r;
}
bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd)
{
bool r = false;
struct dm_thin_device *td, *tmp;
down_read(&pmd->root_lock);
list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
if (td->changed) {
r = td->changed;
break;
}
}
up_read(&pmd->root_lock);
return r;
}
bool dm_thin_aborted_changes(struct dm_thin_device *td)
{
bool r;
down_read(&td->pmd->root_lock);
r = td->aborted_with_changes;
up_read(&td->pmd->root_lock);
return r;
}
int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = dm_sm_new_block(pmd->data_sm, result);
up_write(&pmd->root_lock);
return r;
}
int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (pmd->fail_io)
goto out;
r = __commit_transaction(pmd);
if (r <= 0)
goto out;
/*
* Open the next transaction.
*/
r = __begin_transaction(pmd);
out:
up_write(&pmd->root_lock);
return r;
}
static void __set_abort_with_changes_flags(struct dm_pool_metadata *pmd)
{
struct dm_thin_device *td;
list_for_each_entry(td, &pmd->thin_devices, list)
td->aborted_with_changes = td->changed;
}
int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (pmd->fail_io)
goto out;
__set_abort_with_changes_flags(pmd);
__destroy_persistent_data_objects(pmd);
r = __create_persistent_data_objects(pmd, false);
if (r)
pmd->fail_io = true;
out:
up_write(&pmd->root_lock);
return r;
}
int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
{
int r = -EINVAL;
down_read(&pmd->root_lock);
if (!pmd->fail_io)
r = dm_sm_get_nr_free(pmd->data_sm, result);
up_read(&pmd->root_lock);
return r;
}
int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
dm_block_t *result)
{
int r = -EINVAL;
down_read(&pmd->root_lock);
if (!pmd->fail_io)
r = dm_sm_get_nr_free(pmd->metadata_sm, result);
up_read(&pmd->root_lock);
return r;
}
int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
dm_block_t *result)
{
int r = -EINVAL;
down_read(&pmd->root_lock);
if (!pmd->fail_io)
r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
up_read(&pmd->root_lock);
return r;
}
int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result)
{
down_read(&pmd->root_lock);
*result = pmd->data_block_size;
up_read(&pmd->root_lock);
return 0;
}
int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
{
int r = -EINVAL;
down_read(&pmd->root_lock);
if (!pmd->fail_io)
r = dm_sm_get_nr_blocks(pmd->data_sm, result);
up_read(&pmd->root_lock);
return r;
}
int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
{
int r = -EINVAL;
struct dm_pool_metadata *pmd = td->pmd;
down_read(&pmd->root_lock);
if (!pmd->fail_io) {
*result = td->mapped_blocks;
r = 0;
}
up_read(&pmd->root_lock);
return r;
}
static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
{
int r;
__le64 value_le;
dm_block_t thin_root;
struct dm_pool_metadata *pmd = td->pmd;
r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
if (r)
return r;
thin_root = le64_to_cpu(value_le);
return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
}
int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
dm_block_t *result)
{
int r = -EINVAL;
struct dm_pool_metadata *pmd = td->pmd;
down_read(&pmd->root_lock);
if (!pmd->fail_io)
r = __highest_block(td, result);
up_read(&pmd->root_lock);
return r;
}
static int __resize_space_map(struct dm_space_map *sm, dm_block_t new_count)
{
int r;
dm_block_t old_count;
r = dm_sm_get_nr_blocks(sm, &old_count);
if (r)
return r;
if (new_count == old_count)
return 0;
if (new_count < old_count) {
DMERR("cannot reduce size of space map");
return -EINVAL;
}
return dm_sm_extend(sm, new_count - old_count);
}
int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __resize_space_map(pmd->data_sm, new_count);
up_write(&pmd->root_lock);
return r;
}
int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
{
int r = -EINVAL;
down_write(&pmd->root_lock);
if (!pmd->fail_io)
r = __resize_space_map(pmd->metadata_sm, new_count);
up_write(&pmd->root_lock);
return r;
}
void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
{
down_write(&pmd->root_lock);
pmd->read_only = true;
dm_bm_set_read_only(pmd->bm);
up_write(&pmd->root_lock);
}
void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd)
{
down_write(&pmd->root_lock);
pmd->read_only = false;
dm_bm_set_read_write(pmd->bm);
up_write(&pmd->root_lock);
}
int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
dm_block_t threshold,
dm_sm_threshold_fn fn,
void *context)
{
int r;
down_write(&pmd->root_lock);
r = dm_sm_register_threshold_callback(pmd->metadata_sm, threshold, fn, context);
up_write(&pmd->root_lock);
return r;
}
int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
{
int r;
struct dm_block *sblock;
struct thin_disk_superblock *disk_super;
down_write(&pmd->root_lock);
pmd->flags |= THIN_METADATA_NEEDS_CHECK_FLAG;
r = superblock_lock(pmd, &sblock);
if (r) {
DMERR("couldn't read superblock");
goto out;
}
disk_super = dm_block_data(sblock);
disk_super->flags = cpu_to_le32(pmd->flags);
dm_bm_unlock(sblock);
out:
up_write(&pmd->root_lock);
return r;
}
bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd)
{
bool needs_check;
down_read(&pmd->root_lock);
needs_check = pmd->flags & THIN_METADATA_NEEDS_CHECK_FLAG;
up_read(&pmd->root_lock);
return needs_check;
}
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