diff --git a/Documentation/device-mapper/verity.txt b/Documentation/device-mapper/verity.txt
index e15bc1a0fb98ab23563681210cc6ed1865234816..89fd8f9a259f69b9c9423da9bb16771ed0596cad 100644
--- a/Documentation/device-mapper/verity.txt
+++ b/Documentation/device-mapper/verity.txt
@@ -18,11 +18,11 @@ Construction Parameters
0 is the original format used in the Chromium OS.
The salt is appended when hashing, digests are stored continuously and
- the rest of the block is padded with zeros.
+ the rest of the block is padded with zeroes.
1 is the current format that should be used for new devices.
The salt is prepended when hashing and each digest is
- padded with zeros to the power of two.
+ padded with zeroes to the power of two.
<dev>
This is the device containing data, the integrity of which needs to be
@@ -79,6 +79,37 @@ restart_on_corruption
not compatible with ignore_corruption and requires user space support to
avoid restart loops.
+ignore_zero_blocks
+ Do not verify blocks that are expected to contain zeroes and always return
+ zeroes instead. This may be useful if the partition contains unused blocks
+ that are not guaranteed to contain zeroes.
+
+use_fec_from_device <fec_dev>
+ Use forward error correction (FEC) to recover from corruption if hash
+ verification fails. Use encoding data from the specified device. This
+ may be the same device where data and hash blocks reside, in which case
+ fec_start must be outside data and hash areas.
+
+ If the encoding data covers additional metadata, it must be accessible
+ on the hash device after the hash blocks.
+
+ Note: block sizes for data and hash devices must match. Also, if the
+ verity <dev> is encrypted the <fec_dev> should be too.
+
+fec_roots <num>
+ Number of generator roots. This equals to the number of parity bytes in
+ the encoding data. For example, in RS(M, N) encoding, the number of roots
+ is M-N.
+
+fec_blocks <num>
+ The number of encoding data blocks on the FEC device. The block size for
+ the FEC device is <data_block_size>.
+
+fec_start <offset>
+ This is the offset, in <data_block_size> blocks, from the start of the
+ FEC device to the beginning of the encoding data.
+
+
Theory of operation
===================
@@ -98,6 +129,11 @@ per-block basis. This allows for a lightweight hash computation on first read
into the page cache. Block hashes are stored linearly, aligned to the nearest
block size.
+If forward error correction (FEC) support is enabled any recovery of
+corrupted data will be verified using the cryptographic hash of the
+corresponding data. This is why combining error correction with
+integrity checking is essential.
+
Hash Tree
---------
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 7913fdcfc8496bdd7c719a8c3334f6136c74eced..0a2e7273db9e996ea67d9d461172342aaa65d4f1 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -240,6 +240,15 @@ config DM_BUFIO
as a cache, holding recently-read blocks in memory and performing
delayed writes.
+config DM_DEBUG_BLOCK_STACK_TRACING
+ bool "Keep stack trace of persistent data block lock holders"
+ depends on STACKTRACE_SUPPORT && DM_BUFIO
+ select STACKTRACE
+ ---help---
+ Enable this for messages that may help debug problems with the
+ block manager locking used by thin provisioning and caching.
+
+ If unsure, say N.
config DM_BIO_PRISON
tristate
depends on BLK_DEV_DM
@@ -458,6 +467,18 @@ config DM_VERITY
If unsure, say N.
+config DM_VERITY_FEC
+ bool "Verity forward error correction support"
+ depends on DM_VERITY
+ select REED_SOLOMON
+ select REED_SOLOMON_DEC8
+ ---help---
+ Add forward error correction support to dm-verity. This option
+ makes it possible to use pre-generated error correction data to
+ recover from corrupted blocks.
+
+ If unsure, say N.
+
config DM_SWITCH
tristate "Switch target support (EXPERIMENTAL)"
depends on BLK_DEV_DM
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index f34979cd141aed02d867f11f3f03c9403d327005..62a65764e8e0f093cede342f0eb4b7d0aec2eb4e 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -16,6 +16,7 @@ dm-cache-mq-y += dm-cache-policy-mq.o
dm-cache-smq-y += dm-cache-policy-smq.o
dm-cache-cleaner-y += dm-cache-policy-cleaner.o
dm-era-y += dm-era-target.o
+dm-verity-y += dm-verity-target.o
md-mod-y += md.o bitmap.o
raid456-y += raid5.o raid5-cache.o
@@ -63,3 +64,7 @@ obj-$(CONFIG_DM_LOG_WRITES) += dm-log-writes.o
ifeq ($(CONFIG_DM_UEVENT),y)
dm-mod-objs += dm-uevent.o
endif
+
+ifeq ($(CONFIG_DM_VERITY_FEC),y)
+dm-verity-objs += dm-verity-fec.o
+endif
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 2dd33085b331da5bee79392dcf30f7e2c734f70b..6b832e06580dd6527bbf6e1a92e36c044db62f4a 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -16,6 +16,7 @@
#include <linux/shrinker.h>
#include <linux/module.h>
#include <linux/rbtree.h>
+#include <linux/stacktrace.h>
#define DM_MSG_PREFIX "bufio"
@@ -149,6 +150,11 @@ struct dm_buffer {
struct list_head write_list;
struct bio bio;
struct bio_vec bio_vec[DM_BUFIO_INLINE_VECS];
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+#define MAX_STACK 10
+ struct stack_trace stack_trace;
+ unsigned long stack_entries[MAX_STACK];
+#endif
};
/*----------------------------------------------------------------*/
@@ -253,6 +259,17 @@ static LIST_HEAD(dm_bufio_all_clients);
*/
static DEFINE_MUTEX(dm_bufio_clients_lock);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+static void buffer_record_stack(struct dm_buffer *b)
+{
+ b->stack_trace.nr_entries = 0;
+ b->stack_trace.max_entries = MAX_STACK;
+ b->stack_trace.entries = b->stack_entries;
+ b->stack_trace.skip = 2;
+ save_stack_trace(&b->stack_trace);
+}
+#endif
+
/*----------------------------------------------------------------
* A red/black tree acts as an index for all the buffers.
*--------------------------------------------------------------*/
@@ -454,6 +471,9 @@ static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask)
adjust_total_allocated(b->data_mode, (long)c->block_size);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ memset(&b->stack_trace, 0, sizeof(b->stack_trace));
+#endif
return b;
}
@@ -1063,12 +1083,16 @@ static void *new_read(struct dm_bufio_client *c, sector_t block,
dm_bufio_lock(c);
b = __bufio_new(c, block, nf, &need_submit, &write_list);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ if (b && b->hold_count == 1)
+ buffer_record_stack(b);
+#endif
dm_bufio_unlock(c);
__flush_write_list(&write_list);
if (!b)
- return b;
+ return NULL;
if (need_submit)
submit_io(b, READ, b->block, read_endio);
@@ -1462,6 +1486,7 @@ static void drop_buffers(struct dm_bufio_client *c)
{
struct dm_buffer *b;
int i;
+ bool warned = false;
BUG_ON(dm_bufio_in_request());
@@ -1476,9 +1501,21 @@ static void drop_buffers(struct dm_bufio_client *c)
__free_buffer_wake(b);
for (i = 0; i < LIST_SIZE; i++)
- list_for_each_entry(b, &c->lru[i], lru_list)
+ list_for_each_entry(b, &c->lru[i], lru_list) {
+ WARN_ON(!warned);
+ warned = true;
DMERR("leaked buffer %llx, hold count %u, list %d",
(unsigned long long)b->block, b->hold_count, i);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ print_stack_trace(&b->stack_trace, 1);
+ b->hold_count = 0; /* mark unclaimed to avoid BUG_ON below */
+#endif
+ }
+
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ while ((b = __get_unclaimed_buffer(c)))
+ __free_buffer_wake(b);
+#endif
for (i = 0; i < LIST_SIZE; i++)
BUG_ON(!list_empty(&c->lru[i]));
@@ -1891,8 +1928,7 @@ static void __exit dm_bufio_exit(void)
bug = 1;
}
- if (bug)
- BUG();
+ BUG_ON(bug);
}
module_init(dm_bufio_init)
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 2fd4c82961441e08b2b20d8db98bfb2bad86e05e..5780accffa3059dfa979ef8ff81752bfabd46452 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -118,14 +118,12 @@ static void iot_io_end(struct io_tracker *iot, sector_t len)
*/
struct dm_hook_info {
bio_end_io_t *bi_end_io;
- void *bi_private;
};
static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio,
bio_end_io_t *bi_end_io, void *bi_private)
{
h->bi_end_io = bio->bi_end_io;
- h->bi_private = bio->bi_private;
bio->bi_end_io = bi_end_io;
bio->bi_private = bi_private;
@@ -134,7 +132,6 @@ static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio,
static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio)
{
bio->bi_end_io = h->bi_end_io;
- bio->bi_private = h->bi_private;
}
/*----------------------------------------------------------------*/
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index fae34e7a0b1e4e4d60b5867eff9422e432fba83b..12b5216c2cfed2758d19f55ba9d2c2d4f58d4deb 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -69,7 +69,7 @@ struct dm_exception_store_type {
* Update the metadata with this exception.
*/
void (*commit_exception) (struct dm_exception_store *store,
- struct dm_exception *e,
+ struct dm_exception *e, int valid,
void (*callback) (void *, int success),
void *callback_context);
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 3164b8bce2948591999f429e4633235c1f7b1062..4d3909393f2cce5488ced8843ccab1375d40d2d9 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -695,7 +695,7 @@ static int persistent_prepare_exception(struct dm_exception_store *store,
}
static void persistent_commit_exception(struct dm_exception_store *store,
- struct dm_exception *e,
+ struct dm_exception *e, int valid,
void (*callback) (void *, int success),
void *callback_context)
{
@@ -704,6 +704,9 @@ static void persistent_commit_exception(struct dm_exception_store *store,
struct core_exception ce;
struct commit_callback *cb;
+ if (!valid)
+ ps->valid = 0;
+
ce.old_chunk = e->old_chunk;
ce.new_chunk = e->new_chunk;
write_exception(ps, ps->current_committed++, &ce);
diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
index 9b7c8c8049d6186f54bdfec114c43cb3ce4d77fa..4d50a12cf00c699b85a0df1c0b1dd86f0137b691 100644
--- a/drivers/md/dm-snap-transient.c
+++ b/drivers/md/dm-snap-transient.c
@@ -52,12 +52,12 @@ static int transient_prepare_exception(struct dm_exception_store *store,
}
static void transient_commit_exception(struct dm_exception_store *store,
- struct dm_exception *e,
+ struct dm_exception *e, int valid,
void (*callback) (void *, int success),
void *callback_context)
{
/* Just succeed */
- callback(callback_context, 1);
+ callback(callback_context, valid);
}
static void transient_usage(struct dm_exception_store *store,
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index c06b74e91cd6aeef00ef4eefae9953d4d8c8f91b..3766386080a48fbfb06226ae80646b5e2f0e653a 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -207,7 +207,6 @@ struct dm_snap_pending_exception {
*/
struct bio *full_bio;
bio_end_io_t *full_bio_end_io;
- void *full_bio_private;
};
/*
@@ -1438,8 +1437,9 @@ static void __invalidate_snapshot(struct dm_snapshot *s, int err)
dm_table_event(s->ti->table);
}
-static void pending_complete(struct dm_snap_pending_exception *pe, int success)
+static void pending_complete(void *context, int success)
{
+ struct dm_snap_pending_exception *pe = context;
struct dm_exception *e;
struct dm_snapshot *s = pe->snap;
struct bio *origin_bios = NULL;
@@ -1485,10 +1485,8 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success)
snapshot_bios = bio_list_get(&pe->snapshot_bios);
origin_bios = bio_list_get(&pe->origin_bios);
full_bio = pe->full_bio;
- if (full_bio) {
+ if (full_bio)
full_bio->bi_end_io = pe->full_bio_end_io;
- full_bio->bi_private = pe->full_bio_private;
- }
increment_pending_exceptions_done_count();
up_write(&s->lock);
@@ -1509,24 +1507,13 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success)
free_pending_exception(pe);
}
-static void commit_callback(void *context, int success)
-{
- struct dm_snap_pending_exception *pe = context;
-
- pending_complete(pe, success);
-}
-
static void complete_exception(struct dm_snap_pending_exception *pe)
{
struct dm_snapshot *s = pe->snap;
- if (unlikely(pe->copy_error))
- pending_complete(pe, 0);
-
- else
- /* Update the metadata if we are persistent */
- s->store->type->commit_exception(s->store, &pe->e,
- commit_callback, pe);
+ /* Update the metadata if we are persistent */
+ s->store->type->commit_exception(s->store, &pe->e, !pe->copy_error,
+ pending_complete, pe);
}
/*
@@ -1605,7 +1592,6 @@ static void start_full_bio(struct dm_snap_pending_exception *pe,
pe->full_bio = bio;
pe->full_bio_end_io = bio->bi_end_io;
- pe->full_bio_private = bio->bi_private;
callback_data = dm_kcopyd_prepare_callback(s->kcopyd_client,
copy_callback, pe);
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index c219a053c7f66d1ebae80a19b005af38914dbe8c..f962d6453afd64e33b739253ca4166a276307dab 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -1395,8 +1395,21 @@ 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_issue_io, struct dm_thin_lookup_result *result)
+static void unpack_lookup_result(struct dm_thin_device *td, __le64 value,
+ struct dm_thin_lookup_result *result)
+{
+ uint64_t block_time = 0;
+ dm_block_t exception_block;
+ uint32_t exception_time;
+
+ block_time = le64_to_cpu(value);
+ unpack_block_time(block_time, &exception_block, &exception_time);
+ result->block = exception_block;
+ result->shared = __snapshotted_since(td, exception_time);
+}
+
+static int __find_block(struct dm_thin_device *td, dm_block_t block,
+ int can_issue_io, struct dm_thin_lookup_result *result)
{
int r;
__le64 value;
@@ -1404,39 +1417,56 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
dm_block_t keys[2] = { td->id, block };
struct dm_btree_info *info;
- down_read(&pmd->root_lock);
- if (pmd->fail_io) {
- up_read(&pmd->root_lock);
- return -EINVAL;
- }
-
if (can_issue_io) {
info = &pmd->info;
} else
info = &pmd->nb_info;
r = dm_btree_lookup(info, pmd->root, keys, &value);
- if (!r) {
- uint64_t block_time = 0;
- dm_block_t exception_block;
- uint32_t exception_time;
-
- block_time = le64_to_cpu(value);
- unpack_block_time(block_time, &exception_block,
- &exception_time);
- result->block = exception_block;
- result->shared = __snapshotted_since(td, exception_time);
+ if (!r)
+ unpack_lookup_result(td, value, result);
+
+ return r;
+}
+
+int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
+ int can_issue_io, struct dm_thin_lookup_result *result)
+{
+ int r;
+ struct dm_pool_metadata *pmd = td->pmd;
+
+ down_read(&pmd->root_lock);
+ if (pmd->fail_io) {
+ up_read(&pmd->root_lock);
+ return -EINVAL;
}
+ r = __find_block(td, block, can_issue_io, result);
+
up_read(&pmd->root_lock);
return r;
}
-/* FIXME: write a more efficient one in btree */
-int dm_thin_find_mapped_range(struct dm_thin_device *td,
- dm_block_t begin, dm_block_t end,
- dm_block_t *thin_begin, dm_block_t *thin_end,
- dm_block_t *pool_begin, bool *maybe_shared)
+static int __find_next_mapped_block(struct dm_thin_device *td, dm_block_t block,
+ dm_block_t *vblock,
+ struct dm_thin_lookup_result *result)
+{
+ int r;
+ __le64 value;
+ struct dm_pool_metadata *pmd = td->pmd;
+ dm_block_t keys[2] = { td->id, block };
+
+ r = dm_btree_lookup_next(&pmd->info, pmd->root, keys, vblock, &value);
+ if (!r)
+ unpack_lookup_result(td, value, result);
+
+ return r;
+}
+
+static int __find_mapped_range(struct dm_thin_device *td,
+ dm_block_t begin, dm_block_t end,
+ dm_block_t *thin_begin, dm_block_t *thin_end,
+ dm_block_t *pool_begin, bool *maybe_shared)
{
int r;
dm_block_t pool_end;
@@ -1445,21 +1475,11 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td,
if (end < begin)
return -ENODATA;
- /*
- * Find first mapped block.
- */
- while (begin < end) {
- r = dm_thin_find_block(td, begin, true, &lookup);
- if (r) {
- if (r != -ENODATA)
- return r;
- } else
- break;
-
- begin++;
- }
+ r = __find_next_mapped_block(td, begin, &begin, &lookup);
+ if (r)
+ return r;
- if (begin == end)
+ if (begin >= end)
return -ENODATA;
*thin_begin = begin;
@@ -1469,7 +1489,7 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td,
begin++;
pool_end = *pool_begin + 1;
while (begin != end) {
- r = dm_thin_find_block(td, begin, true, &lookup);
+ r = __find_block(td, begin, true, &lookup);
if (r) {
if (r == -ENODATA)
break;
@@ -1489,6 +1509,24 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td,
return 0;
}
+int dm_thin_find_mapped_range(struct dm_thin_device *td,
+ dm_block_t begin, dm_block_t end,
+ dm_block_t *thin_begin, dm_block_t *thin_end,
+ dm_block_t *pool_begin, bool *maybe_shared)
+{
+ int r = -EINVAL;
+ struct dm_pool_metadata *pmd = td->pmd;
+
+ down_read(&pmd->root_lock);
+ if (!pmd->fail_io) {
+ r = __find_mapped_range(td, begin, end, thin_begin, thin_end,
+ pool_begin, maybe_shared);
+ }
+ up_read(&pmd->root_lock);
+
+ return r;
+}
+
static int __insert(struct dm_thin_device *td, dm_block_t block,
dm_block_t data_block)
{
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 63903a5a5d9ee3b580d552673b42b9716b99322c..72d91f477683f2c1dfad5a3a9614aaf0b26992e1 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3453,8 +3453,8 @@ static void pool_postsuspend(struct dm_target *ti)
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
- cancel_delayed_work(&pool->waker);
- cancel_delayed_work(&pool->no_space_timeout);
+ cancel_delayed_work_sync(&pool->waker);
+ cancel_delayed_work_sync(&pool->no_space_timeout);
flush_workqueue(pool->wq);
(void) commit(pool);
}
@@ -3886,7 +3886,7 @@ static struct target_type pool_target = {
.name = "thin-pool",
.features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
DM_TARGET_IMMUTABLE,
- .version = {1, 16, 0},
+ .version = {1, 17, 0},
.module = THIS_MODULE,
.ctr = pool_ctr,
.dtr = pool_dtr,
@@ -4260,7 +4260,7 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
static struct target_type thin_target = {
.name = "thin",
- .version = {1, 16, 0},
+ .version = {1, 17, 0},
.module = THIS_MODULE,
.ctr = thin_ctr,
.dtr = thin_dtr,
diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
new file mode 100644
index 0000000000000000000000000000000000000000..1cc10c4de70101ace370a7716c2a0d5f42887ce2
--- /dev/null
+++ b/drivers/md/dm-verity-fec.c
@@ -0,0 +1,818 @@
+/*
+ * Copyright (C) 2015 Google, Inc.
+ *
+ * Author: Sami Tolvanen <samitolvanen@google.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include "dm-verity-fec.h"
+#include <linux/math64.h>
+
+#define DM_MSG_PREFIX "verity-fec"
+
+/*
+ * If error correction has been configured, returns true.
+ */
+bool verity_fec_is_enabled(struct dm_verity *v)
+{
+ return v->fec && v->fec->dev;
+}
+
+/*
+ * Return a pointer to dm_verity_fec_io after dm_verity_io and its variable
+ * length fields.
+ */
+static inline struct dm_verity_fec_io *fec_io(struct dm_verity_io *io)
+{
+ return (struct dm_verity_fec_io *) verity_io_digest_end(io->v, io);
+}
+
+/*
+ * Return an interleaved offset for a byte in RS block.
+ */
+static inline u64 fec_interleave(struct dm_verity *v, u64 offset)
+{
+ u32 mod;
+
+ mod = do_div(offset, v->fec->rsn);
+ return offset + mod * (v->fec->rounds << v->data_dev_block_bits);
+}
+
+/*
+ * Decode an RS block using Reed-Solomon.
+ */
+static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,
+ u8 *data, u8 *fec, int neras)
+{
+ int i;
+ uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
+
+ for (i = 0; i < v->fec->roots; i++)
+ par[i] = fec[i];
+
+ return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras,
+ fio->erasures, 0, NULL);
+}
+
+/*
+ * Read error-correcting codes for the requested RS block. Returns a pointer
+ * to the data block. Caller is responsible for releasing buf.
+ */
+static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,
+ unsigned *offset, struct dm_buffer **buf)
+{
+ u64 position, block;
+ u8 *res;
+
+ position = (index + rsb) * v->fec->roots;
+ block = position >> v->data_dev_block_bits;
+ *offset = (unsigned)(position - (block << v->data_dev_block_bits));
+
+ res = dm_bufio_read(v->fec->bufio, v->fec->start + block, buf);
+ if (unlikely(IS_ERR(res))) {
+ DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
+ v->data_dev->name, (unsigned long long)rsb,
+ (unsigned long long)(v->fec->start + block),
+ PTR_ERR(res));
+ *buf = NULL;
+ }
+
+ return res;
+}
+
+/* Loop over each preallocated buffer slot. */
+#define fec_for_each_prealloc_buffer(__i) \
+ for (__i = 0; __i < DM_VERITY_FEC_BUF_PREALLOC; __i++)
+
+/* Loop over each extra buffer slot. */
+#define fec_for_each_extra_buffer(io, __i) \
+ for (__i = DM_VERITY_FEC_BUF_PREALLOC; __i < DM_VERITY_FEC_BUF_MAX; __i++)
+
+/* Loop over each allocated buffer. */
+#define fec_for_each_buffer(io, __i) \
+ for (__i = 0; __i < (io)->nbufs; __i++)
+
+/* Loop over each RS block in each allocated buffer. */
+#define fec_for_each_buffer_rs_block(io, __i, __j) \
+ fec_for_each_buffer(io, __i) \
+ for (__j = 0; __j < 1 << DM_VERITY_FEC_BUF_RS_BITS; __j++)
+
+/*
+ * Return a pointer to the current RS block when called inside
+ * fec_for_each_buffer_rs_block.
+ */
+static inline u8 *fec_buffer_rs_block(struct dm_verity *v,
+ struct dm_verity_fec_io *fio,
+ unsigned i, unsigned j)
+{
+ return &fio->bufs[i][j * v->fec->rsn];
+}
+
+/*
+ * Return an index to the current RS block when called inside
+ * fec_for_each_buffer_rs_block.
+ */
+static inline unsigned fec_buffer_rs_index(unsigned i, unsigned j)
+{
+ return (i << DM_VERITY_FEC_BUF_RS_BITS) + j;
+}
+
+/*
+ * Decode all RS blocks from buffers and copy corrected bytes into fio->output
+ * starting from block_offset.
+ */
+static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio,
+ u64 rsb, int byte_index, unsigned block_offset,
+ int neras)
+{
+ int r, corrected = 0, res;
+ struct dm_buffer *buf;
+ unsigned n, i, offset;
+ u8 *par, *block;
+
+ par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
+ if (IS_ERR(par))
+ return PTR_ERR(par);
+
+ /*
+ * Decode the RS blocks we have in bufs. Each RS block results in
+ * one corrected target byte and consumes fec->roots parity bytes.
+ */
+ fec_for_each_buffer_rs_block(fio, n, i) {
+ block = fec_buffer_rs_block(v, fio, n, i);
+ res = fec_decode_rs8(v, fio, block, &par[offset], neras);
+ if (res < 0) {
+ dm_bufio_release(buf);
+
+ r = res;
+ goto error;
+ }
+
+ corrected += res;
+ fio->output[block_offset] = block[byte_index];
+
+ block_offset++;
+ if (block_offset >= 1 << v->data_dev_block_bits)
+ goto done;
+
+ /* read the next block when we run out of parity bytes */
+ offset += v->fec->roots;
+ if (offset >= 1 << v->data_dev_block_bits) {
+ dm_bufio_release(buf);
+
+ par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
+ if (unlikely(IS_ERR(par)))
+ return PTR_ERR(par);
+ }
+ }
+done:
+ r = corrected;
+error:
+ if (r < 0 && neras)
+ DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",
+ v->data_dev->name, (unsigned long long)rsb, r);
+ else if (r > 0)
+ DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",
+ v->data_dev->name, (unsigned long long)rsb, r);
+
+ return r;
+}
+
+/*
+ * Locate data block erasures using verity hashes.
+ */
+static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io,
+ u8 *want_digest, u8 *data)
+{
+ if (unlikely(verity_hash(v, verity_io_hash_desc(v, io),
+ data, 1 << v->data_dev_block_bits,
+ verity_io_real_digest(v, io))))
+ return 0;
+
+ return memcmp(verity_io_real_digest(v, io), want_digest,
+ v->digest_size) != 0;
+}
+
+/*
+ * Read data blocks that are part of the RS block and deinterleave as much as
+ * fits into buffers. Check for erasure locations if @neras is non-NULL.
+ */
+static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
+ u64 rsb, u64 target, unsigned block_offset,
+ int *neras)
+{
+ bool is_zero;
+ int i, j, target_index = -1;
+ struct dm_buffer *buf;
+ struct dm_bufio_client *bufio;
+ struct dm_verity_fec_io *fio = fec_io(io);
+ u64 block, ileaved;
+ u8 *bbuf, *rs_block;
+ u8 want_digest[v->digest_size];
+ unsigned n, k;
+
+ if (neras)
+ *neras = 0;
+
+ /*
+ * read each of the rsn data blocks that are part of the RS block, and
+ * interleave contents to available bufs
+ */
+ for (i = 0; i < v->fec->rsn; i++) {
+ ileaved = fec_interleave(v, rsb * v->fec->rsn + i);
+
+ /*
+ * target is the data block we want to correct, target_index is
+ * the index of this block within the rsn RS blocks
+ */
+ if (ileaved == target)
+ target_index = i;
+
+ block = ileaved >> v->data_dev_block_bits;
+ bufio = v->fec->data_bufio;
+
+ if (block >= v->data_blocks) {
+ block -= v->data_blocks;
+
+ /*
+ * blocks outside the area were assumed to contain
+ * zeros when encoding data was generated
+ */
+ if (unlikely(block >= v->fec->hash_blocks))
+ continue;
+
+ block += v->hash_start;
+ bufio = v->bufio;
+ }
+
+ bbuf = dm_bufio_read(bufio, block, &buf);
+ if (unlikely(IS_ERR(bbuf))) {
+ DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",
+ v->data_dev->name,
+ (unsigned long long)rsb,
+ (unsigned long long)block, PTR_ERR(bbuf));
+
+ /* assume the block is corrupted */
+ if (neras && *neras <= v->fec->roots)
+ fio->erasures[(*neras)++] = i;
+
+ continue;
+ }
+
+ /* locate erasures if the block is on the data device */
+ if (bufio == v->fec->data_bufio &&
+ verity_hash_for_block(v, io, block, want_digest,
+ &is_zero) == 0) {
+ /* skip known zero blocks entirely */
+ if (is_zero)
+ continue;
+
+ /*
+ * skip if we have already found the theoretical
+ * maximum number (i.e. fec->roots) of erasures
+ */
+ if (neras && *neras <= v->fec->roots &&
+ fec_is_erasure(v, io, want_digest, bbuf))
+ fio->erasures[(*neras)++] = i;
+ }
+
+ /*
+ * deinterleave and copy the bytes that fit into bufs,
+ * starting from block_offset
+ */
+ fec_for_each_buffer_rs_block(fio, n, j) {
+ k = fec_buffer_rs_index(n, j) + block_offset;
+
+ if (k >= 1 << v->data_dev_block_bits)
+ goto done;
+
+ rs_block = fec_buffer_rs_block(v, fio, n, j);
+ rs_block[i] = bbuf[k];
+ }
+done:
+ dm_bufio_release(buf);
+ }
+
+ return target_index;
+}
+
+/*
+ * Allocate RS control structure and FEC buffers from preallocated mempools,
+ * and attempt to allocate as many extra buffers as available.
+ */
+static int fec_alloc_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
+{
+ unsigned n;
+
+ if (!fio->rs) {
+ fio->rs = mempool_alloc(v->fec->rs_pool, 0);
+ if (unlikely(!fio->rs)) {
+ DMERR("failed to allocate RS");
+ return -ENOMEM;
+ }
+ }
+
+ fec_for_each_prealloc_buffer(n) {
+ if (fio->bufs[n])
+ continue;
+
+ fio->bufs[n] = mempool_alloc(v->fec->prealloc_pool, GFP_NOIO);
+ if (unlikely(!fio->bufs[n])) {
+ DMERR("failed to allocate FEC buffer");
+ return -ENOMEM;
+ }
+ }
+
+ /* try to allocate the maximum number of buffers */
+ fec_for_each_extra_buffer(fio, n) {
+ if (fio->bufs[n])
+ continue;
+
+ fio->bufs[n] = mempool_alloc(v->fec->extra_pool, GFP_NOIO);
+ /* we can manage with even one buffer if necessary */
+ if (unlikely(!fio->bufs[n]))
+ break;
+ }
+ fio->nbufs = n;
+
+ if (!fio->output) {
+ fio->output = mempool_alloc(v->fec->output_pool, GFP_NOIO);
+
+ if (!fio->output) {
+ DMERR("failed to allocate FEC page");
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Initialize buffers and clear erasures. fec_read_bufs() assumes buffers are
+ * zeroed before deinterleaving.
+ */
+static void fec_init_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
+{
+ unsigned n;
+
+ fec_for_each_buffer(fio, n)
+ memset(fio->bufs[n], 0, v->fec->rsn << DM_VERITY_FEC_BUF_RS_BITS);
+
+ memset(fio->erasures, 0, sizeof(fio->erasures));
+}
+
+/*
+ * Decode all RS blocks in a single data block and return the target block
+ * (indicated by @offset) in fio->output. If @use_erasures is non-zero, uses
+ * hashes to locate erasures.
+ */
+static int fec_decode_rsb(struct dm_verity *v, struct dm_verity_io *io,
+ struct dm_verity_fec_io *fio, u64 rsb, u64 offset,
+ bool use_erasures)
+{
+ int r, neras = 0;
+ unsigned pos;
+
+ r = fec_alloc_bufs(v, fio);
+ if (unlikely(r < 0))
+ return r;
+
+ for (pos = 0; pos < 1 << v->data_dev_block_bits; ) {
+ fec_init_bufs(v, fio);
+
+ r = fec_read_bufs(v, io, rsb, offset, pos,
+ use_erasures ? &neras : NULL);
+ if (unlikely(r < 0))
+ return r;
+
+ r = fec_decode_bufs(v, fio, rsb, r, pos, neras);
+ if (r < 0)
+ return r;
+
+ pos += fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS;
+ }
+
+ /* Always re-validate the corrected block against the expected hash */
+ r = verity_hash(v, verity_io_hash_desc(v, io), fio->output,
+ 1 << v->data_dev_block_bits,
+ verity_io_real_digest(v, io));
+ if (unlikely(r < 0))
+ return r;
+
+ if (memcmp(verity_io_real_digest(v, io), verity_io_want_digest(v, io),
+ v->digest_size)) {
+ DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)",
+ v->data_dev->name, (unsigned long long)rsb, neras);
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+static int fec_bv_copy(struct dm_verity *v, struct dm_verity_io *io, u8 *data,
+ size_t len)
+{
+ struct dm_verity_fec_io *fio = fec_io(io);
+
+ memcpy(data, &fio->output[fio->output_pos], len);
+ fio->output_pos += len;
+
+ return 0;
+}
+
+/*
+ * Correct errors in a block. Copies corrected block to dest if non-NULL,
+ * otherwise to a bio_vec starting from iter.
+ */
+int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,
+ enum verity_block_type type, sector_t block, u8 *dest,
+ struct bvec_iter *iter)
+{
+ int r;
+ struct dm_verity_fec_io *fio = fec_io(io);
+ u64 offset, res, rsb;
+
+ if (!verity_fec_is_enabled(v))
+ return -EOPNOTSUPP;
+
+ if (type == DM_VERITY_BLOCK_TYPE_METADATA)
+ block += v->data_blocks;
+
+ /*
+ * For RS(M, N), the continuous FEC data is divided into blocks of N
+ * bytes. Since block size may not be divisible by N, the last block
+ * is zero padded when decoding.
+ *
+ * Each byte of the block is covered by a different RS(M, N) code,
+ * and each code is interleaved over N blocks to make it less likely
+ * that bursty corruption will leave us in unrecoverable state.
+ */
+
+ offset = block << v->data_dev_block_bits;
+
+ res = offset;
+ div64_u64(res, v->fec->rounds << v->data_dev_block_bits);
+
+ /*
+ * The base RS block we can feed to the interleaver to find out all
+ * blocks required for decoding.
+ */
+ rsb = offset - res * (v->fec->rounds << v->data_dev_block_bits);
+
+ /*
+ * Locating erasures is slow, so attempt to recover the block without
+ * them first. Do a second attempt with erasures if the corruption is
+ * bad enough.
+ */
+ r = fec_decode_rsb(v, io, fio, rsb, offset, false);
+ if (r < 0) {
+ r = fec_decode_rsb(v, io, fio, rsb, offset, true);
+ if (r < 0)
+ return r;
+ }
+
+ if (dest)
+ memcpy(dest, fio->output, 1 << v->data_dev_block_bits);
+ else if (iter) {
+ fio->output_pos = 0;
+ r = verity_for_bv_block(v, io, iter, fec_bv_copy);
+ }
+
+ return r;
+}
+
+/*
+ * Clean up per-bio data.
+ */
+void verity_fec_finish_io(struct dm_verity_io *io)
+{
+ unsigned n;
+ struct dm_verity_fec *f = io->v->fec;
+ struct dm_verity_fec_io *fio = fec_io(io);
+
+ if (!verity_fec_is_enabled(io->v))
+ return;
+
+ mempool_free(fio->rs, f->rs_pool);
+
+ fec_for_each_prealloc_buffer(n)
+ mempool_free(fio->bufs[n], f->prealloc_pool);
+
+ fec_for_each_extra_buffer(fio, n)
+ mempool_free(fio->bufs[n], f->extra_pool);
+
+ mempool_free(fio->output, f->output_pool);
+}
+
+/*
+ * Initialize per-bio data.
+ */
+void verity_fec_init_io(struct dm_verity_io *io)
+{
+ struct dm_verity_fec_io *fio = fec_io(io);
+
+ if (!verity_fec_is_enabled(io->v))
+ return;
+
+ fio->rs = NULL;
+ memset(fio->bufs, 0, sizeof(fio->bufs));
+ fio->nbufs = 0;
+ fio->output = NULL;
+}
+
+/*
+ * Append feature arguments and values to the status table.
+ */
+unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz,
+ char *result, unsigned maxlen)
+{
+ if (!verity_fec_is_enabled(v))
+ return sz;
+
+ DMEMIT(" " DM_VERITY_OPT_FEC_DEV " %s "
+ DM_VERITY_OPT_FEC_BLOCKS " %llu "
+ DM_VERITY_OPT_FEC_START " %llu "
+ DM_VERITY_OPT_FEC_ROOTS " %d",
+ v->fec->dev->name,
+ (unsigned long long)v->fec->blocks,
+ (unsigned long long)v->fec->start,
+ v->fec->roots);
+
+ return sz;
+}
+
+void verity_fec_dtr(struct dm_verity *v)
+{
+ struct dm_verity_fec *f = v->fec;
+
+ if (!verity_fec_is_enabled(v))
+ goto out;
+
+ mempool_destroy(f->rs_pool);
+ mempool_destroy(f->prealloc_pool);
+ mempool_destroy(f->extra_pool);
+ kmem_cache_destroy(f->cache);
+
+ if (f->data_bufio)
+ dm_bufio_client_destroy(f->data_bufio);
+ if (f->bufio)
+ dm_bufio_client_destroy(f->bufio);
+
+ if (f->dev)
+ dm_put_device(v->ti, f->dev);
+out:
+ kfree(f);
+ v->fec = NULL;
+}
+
+static void *fec_rs_alloc(gfp_t gfp_mask, void *pool_data)
+{
+ struct dm_verity *v = (struct dm_verity *)pool_data;
+
+ return init_rs(8, 0x11d, 0, 1, v->fec->roots);
+}
+
+static void fec_rs_free(void *element, void *pool_data)
+{
+ struct rs_control *rs = (struct rs_control *)element;
+
+ if (rs)
+ free_rs(rs);
+}
+
+bool verity_is_fec_opt_arg(const char *arg_name)
+{
+ return (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV) ||
+ !strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS) ||
+ !strcasecmp(arg_name, DM_VERITY_OPT_FEC_START) ||
+ !strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS));
+}
+
+int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
+ unsigned *argc, const char *arg_name)
+{
+ int r;
+ struct dm_target *ti = v->ti;
+ const char *arg_value;
+ unsigned long long num_ll;
+ unsigned char num_c;
+ char dummy;
+
+ if (!*argc) {
+ ti->error = "FEC feature arguments require a value";
+ return -EINVAL;
+ }
+
+ arg_value = dm_shift_arg(as);
+ (*argc)--;
+
+ if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) {
+ r = dm_get_device(ti, arg_value, FMODE_READ, &v->fec->dev);
+ if (r) {
+ ti->error = "FEC device lookup failed";
+ return r;
+ }
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS)) {
+ if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
+ ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
+ >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
+ return -EINVAL;
+ }
+ v->fec->blocks = num_ll;
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_START)) {
+ if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
+ ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) >>
+ (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_START;
+ return -EINVAL;
+ }
+ v->fec->start = num_ll;
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)) {
+ if (sscanf(arg_value, "%hhu%c", &num_c, &dummy) != 1 || !num_c ||
+ num_c < (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MAX_RSN) ||
+ num_c > (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN)) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_ROOTS;
+ return -EINVAL;
+ }
+ v->fec->roots = num_c;
+
+ } else {
+ ti->error = "Unrecognized verity FEC feature request";
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr.
+ */
+int verity_fec_ctr_alloc(struct dm_verity *v)
+{
+ struct dm_verity_fec *f;
+
+ f = kzalloc(sizeof(struct dm_verity_fec), GFP_KERNEL);
+ if (!f) {
+ v->ti->error = "Cannot allocate FEC structure";
+ return -ENOMEM;
+ }
+ v->fec = f;
+
+ return 0;
+}
+
+/*
+ * Validate arguments and preallocate memory. Must be called after arguments
+ * have been parsed using verity_fec_parse_opt_args.
+ */
+int verity_fec_ctr(struct dm_verity *v)
+{
+ struct dm_verity_fec *f = v->fec;
+ struct dm_target *ti = v->ti;
+ u64 hash_blocks;
+
+ if (!verity_fec_is_enabled(v)) {
+ verity_fec_dtr(v);
+ return 0;
+ }
+
+ /*
+ * FEC is computed over data blocks, possible metadata, and
+ * hash blocks. In other words, FEC covers total of fec_blocks
+ * blocks consisting of the following:
+ *
+ * data blocks | hash blocks | metadata (optional)
+ *
+ * We allow metadata after hash blocks to support a use case
+ * where all data is stored on the same device and FEC covers
+ * the entire area.
+ *
+ * If metadata is included, we require it to be available on the
+ * hash device after the hash blocks.
+ */
+
+ hash_blocks = v->hash_blocks - v->hash_start;
+
+ /*
+ * Require matching block sizes for data and hash devices for
+ * simplicity.
+ */
+ if (v->data_dev_block_bits != v->hash_dev_block_bits) {
+ ti->error = "Block sizes must match to use FEC";
+ return -EINVAL;
+ }
+
+ if (!f->roots) {
+ ti->error = "Missing " DM_VERITY_OPT_FEC_ROOTS;
+ return -EINVAL;
+ }
+ f->rsn = DM_VERITY_FEC_RSM - f->roots;
+
+ if (!f->blocks) {
+ ti->error = "Missing " DM_VERITY_OPT_FEC_BLOCKS;
+ return -EINVAL;
+ }
+
+ f->rounds = f->blocks;
+ if (sector_div(f->rounds, f->rsn))
+ f->rounds++;
+
+ /*
+ * Due to optional metadata, f->blocks can be larger than
+ * data_blocks and hash_blocks combined.
+ */
+ if (f->blocks < v->data_blocks + hash_blocks || !f->rounds) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
+ return -EINVAL;
+ }
+
+ /*
+ * Metadata is accessed through the hash device, so we require
+ * it to be large enough.
+ */
+ f->hash_blocks = f->blocks - v->data_blocks;
+ if (dm_bufio_get_device_size(v->bufio) < f->hash_blocks) {
+ ti->error = "Hash device is too small for "
+ DM_VERITY_OPT_FEC_BLOCKS;
+ return -E2BIG;
+ }
+
+ f->bufio = dm_bufio_client_create(f->dev->bdev,
+ 1 << v->data_dev_block_bits,
+ 1, 0, NULL, NULL);
+ if (IS_ERR(f->bufio)) {
+ ti->error = "Cannot initialize FEC bufio client";
+ return PTR_ERR(f->bufio);
+ }
+
+ if (dm_bufio_get_device_size(f->bufio) <
+ ((f->start + f->rounds * f->roots) >> v->data_dev_block_bits)) {
+ ti->error = "FEC device is too small";
+ return -E2BIG;
+ }
+
+ f->data_bufio = dm_bufio_client_create(v->data_dev->bdev,
+ 1 << v->data_dev_block_bits,
+ 1, 0, NULL, NULL);
+ if (IS_ERR(f->data_bufio)) {
+ ti->error = "Cannot initialize FEC data bufio client";
+ return PTR_ERR(f->data_bufio);
+ }
+
+ if (dm_bufio_get_device_size(f->data_bufio) < v->data_blocks) {
+ ti->error = "Data device is too small";
+ return -E2BIG;
+ }
+
+ /* Preallocate an rs_control structure for each worker thread */
+ f->rs_pool = mempool_create(num_online_cpus(), fec_rs_alloc,
+ fec_rs_free, (void *) v);
+ if (!f->rs_pool) {
+ ti->error = "Cannot allocate RS pool";
+ return -ENOMEM;
+ }
+
+ f->cache = kmem_cache_create("dm_verity_fec_buffers",
+ f->rsn << DM_VERITY_FEC_BUF_RS_BITS,
+ 0, 0, NULL);
+ if (!f->cache) {
+ ti->error = "Cannot create FEC buffer cache";
+ return -ENOMEM;
+ }
+
+ /* Preallocate DM_VERITY_FEC_BUF_PREALLOC buffers for each thread */
+ f->prealloc_pool = mempool_create_slab_pool(num_online_cpus() *
+ DM_VERITY_FEC_BUF_PREALLOC,
+ f->cache);
+ if (!f->prealloc_pool) {
+ ti->error = "Cannot allocate FEC buffer prealloc pool";
+ return -ENOMEM;
+ }
+
+ f->extra_pool = mempool_create_slab_pool(0, f->cache);
+ if (!f->extra_pool) {
+ ti->error = "Cannot allocate FEC buffer extra pool";
+ return -ENOMEM;
+ }
+
+ /* Preallocate an output buffer for each thread */
+ f->output_pool = mempool_create_kmalloc_pool(num_online_cpus(),
+ 1 << v->data_dev_block_bits);
+ if (!f->output_pool) {
+ ti->error = "Cannot allocate FEC output pool";
+ return -ENOMEM;
+ }
+
+ /* Reserve space for our per-bio data */
+ ti->per_bio_data_size += sizeof(struct dm_verity_fec_io);
+
+ return 0;
+}
diff --git a/drivers/md/dm-verity-fec.h b/drivers/md/dm-verity-fec.h
new file mode 100644
index 0000000000000000000000000000000000000000..7fa0298b995e9e3f1ac25c2356c758fad8b65d34
--- /dev/null
+++ b/drivers/md/dm-verity-fec.h
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2015 Google, Inc.
+ *
+ * Author: Sami Tolvanen <samitolvanen@google.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#ifndef DM_VERITY_FEC_H
+#define DM_VERITY_FEC_H
+
+#include "dm-verity.h"
+#include <linux/rslib.h>
+
+/* Reed-Solomon(M, N) parameters */
+#define DM_VERITY_FEC_RSM 255
+#define DM_VERITY_FEC_MAX_RSN 253
+#define DM_VERITY_FEC_MIN_RSN 231 /* ~10% space overhead */
+
+/* buffers for deinterleaving and decoding */
+#define DM_VERITY_FEC_BUF_PREALLOC 1 /* buffers to preallocate */
+#define DM_VERITY_FEC_BUF_RS_BITS 4 /* 1 << RS blocks per buffer */
+/* we need buffers for at most 1 << block size RS blocks */
+#define DM_VERITY_FEC_BUF_MAX \
+ (1 << (PAGE_SHIFT - DM_VERITY_FEC_BUF_RS_BITS))
+
+#define DM_VERITY_OPT_FEC_DEV "use_fec_from_device"
+#define DM_VERITY_OPT_FEC_BLOCKS "fec_blocks"
+#define DM_VERITY_OPT_FEC_START "fec_start"
+#define DM_VERITY_OPT_FEC_ROOTS "fec_roots"
+
+/* configuration */
+struct dm_verity_fec {
+ struct dm_dev *dev; /* parity data device */
+ struct dm_bufio_client *data_bufio; /* for data dev access */
+ struct dm_bufio_client *bufio; /* for parity data access */
+ sector_t start; /* parity data start in blocks */
+ sector_t blocks; /* number of blocks covered */
+ sector_t rounds; /* number of interleaving rounds */
+ sector_t hash_blocks; /* blocks covered after v->hash_start */
+ unsigned char roots; /* number of parity bytes, M-N of RS(M, N) */
+ unsigned char rsn; /* N of RS(M, N) */
+ mempool_t *rs_pool; /* mempool for fio->rs */
+ mempool_t *prealloc_pool; /* mempool for preallocated buffers */
+ mempool_t *extra_pool; /* mempool for extra buffers */
+ mempool_t *output_pool; /* mempool for output */
+ struct kmem_cache *cache; /* cache for buffers */
+};
+
+/* per-bio data */
+struct dm_verity_fec_io {
+ struct rs_control *rs; /* Reed-Solomon state */
+ int erasures[DM_VERITY_FEC_MAX_RSN]; /* erasures for decode_rs8 */
+ u8 *bufs[DM_VERITY_FEC_BUF_MAX]; /* bufs for deinterleaving */
+ unsigned nbufs; /* number of buffers allocated */
+ u8 *output; /* buffer for corrected output */
+ size_t output_pos;
+};
+
+#ifdef CONFIG_DM_VERITY_FEC
+
+/* each feature parameter requires a value */
+#define DM_VERITY_OPTS_FEC 8
+
+extern bool verity_fec_is_enabled(struct dm_verity *v);
+
+extern int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,
+ enum verity_block_type type, sector_t block,
+ u8 *dest, struct bvec_iter *iter);
+
+extern unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz,
+ char *result, unsigned maxlen);
+
+extern void verity_fec_finish_io(struct dm_verity_io *io);
+extern void verity_fec_init_io(struct dm_verity_io *io);
+
+extern bool verity_is_fec_opt_arg(const char *arg_name);
+extern int verity_fec_parse_opt_args(struct dm_arg_set *as,
+ struct dm_verity *v, unsigned *argc,
+ const char *arg_name);
+
+extern void verity_fec_dtr(struct dm_verity *v);
+
+extern int verity_fec_ctr_alloc(struct dm_verity *v);
+extern int verity_fec_ctr(struct dm_verity *v);
+
+#else /* !CONFIG_DM_VERITY_FEC */
+
+#define DM_VERITY_OPTS_FEC 0
+
+static inline bool verity_fec_is_enabled(struct dm_verity *v)
+{
+ return false;
+}
+
+static inline int verity_fec_decode(struct dm_verity *v,
+ struct dm_verity_io *io,
+ enum verity_block_type type,
+ sector_t block, u8 *dest,
+ struct bvec_iter *iter)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline unsigned verity_fec_status_table(struct dm_verity *v,
+ unsigned sz, char *result,
+ unsigned maxlen)
+{
+ return sz;
+}
+
+static inline void verity_fec_finish_io(struct dm_verity_io *io)
+{
+}
+
+static inline void verity_fec_init_io(struct dm_verity_io *io)
+{
+}
+
+static inline bool verity_is_fec_opt_arg(const char *arg_name)
+{
+ return false;
+}
+
+static inline int verity_fec_parse_opt_args(struct dm_arg_set *as,
+ struct dm_verity *v,
+ unsigned *argc,
+ const char *arg_name)
+{
+ return -EINVAL;
+}
+
+static inline void verity_fec_dtr(struct dm_verity *v)
+{
+}
+
+static inline int verity_fec_ctr_alloc(struct dm_verity *v)
+{
+ return 0;
+}
+
+static inline int verity_fec_ctr(struct dm_verity *v)
+{
+ return 0;
+}
+
+#endif /* CONFIG_DM_VERITY_FEC */
+
+#endif /* DM_VERITY_FEC_H */
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity-target.c
similarity index 69%
rename from drivers/md/dm-verity.c
rename to drivers/md/dm-verity-target.c
index ccf41886ebcf49790fe7fddb4aa7f9e581f0bbe3..5c5d30cb6ec59bba067fa3f97808353004ea8aec 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity-target.c
@@ -14,12 +14,11 @@
* access behavior.
*/
-#include "dm-bufio.h"
+#include "dm-verity.h"
+#include "dm-verity-fec.h"
#include <linux/module.h>
-#include <linux/device-mapper.h>
#include <linux/reboot.h>
-#include <crypto/hash.h>
#define DM_MSG_PREFIX "verity"
@@ -28,83 +27,18 @@
#define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144
-#define DM_VERITY_MAX_LEVELS 63
#define DM_VERITY_MAX_CORRUPTED_ERRS 100
#define DM_VERITY_OPT_LOGGING "ignore_corruption"
#define DM_VERITY_OPT_RESTART "restart_on_corruption"
+#define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks"
+
+#define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC)
static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);
-enum verity_mode {
- DM_VERITY_MODE_EIO,
- DM_VERITY_MODE_LOGGING,
- DM_VERITY_MODE_RESTART
-};
-
-enum verity_block_type {
- DM_VERITY_BLOCK_TYPE_DATA,
- DM_VERITY_BLOCK_TYPE_METADATA
-};
-
-struct dm_verity {
- struct dm_dev *data_dev;
- struct dm_dev *hash_dev;
- struct dm_target *ti;
- struct dm_bufio_client *bufio;
- char *alg_name;
- struct crypto_shash *tfm;
- u8 *root_digest; /* digest of the root block */
- u8 *salt; /* salt: its size is salt_size */
- unsigned salt_size;
- sector_t data_start; /* data offset in 512-byte sectors */
- sector_t hash_start; /* hash start in blocks */
- sector_t data_blocks; /* the number of data blocks */
- sector_t hash_blocks; /* the number of hash blocks */
- unsigned char data_dev_block_bits; /* log2(data blocksize) */
- unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
- unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
- unsigned char levels; /* the number of tree levels */
- unsigned char version;
- unsigned digest_size; /* digest size for the current hash algorithm */
- unsigned shash_descsize;/* the size of temporary space for crypto */
- int hash_failed; /* set to 1 if hash of any block failed */
- enum verity_mode mode; /* mode for handling verification errors */
- unsigned corrupted_errs;/* Number of errors for corrupted blocks */
-
- struct workqueue_struct *verify_wq;
-
- /* starting blocks for each tree level. 0 is the lowest level. */
- sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
-};
-
-struct dm_verity_io {
- struct dm_verity *v;
-
- /* original values of bio->bi_end_io and bio->bi_private */
- bio_end_io_t *orig_bi_end_io;
- void *orig_bi_private;
-
- sector_t block;
- unsigned n_blocks;
-
- struct bvec_iter iter;
-
- struct work_struct work;
-
- /*
- * Three variably-size fields follow this struct:
- *
- * u8 hash_desc[v->shash_descsize];
- * u8 real_digest[v->digest_size];
- * u8 want_digest[v->digest_size];
- *
- * To access them use: io_hash_desc(), io_real_digest() and io_want_digest().
- */
-};
-
struct dm_verity_prefetch_work {
struct work_struct work;
struct dm_verity *v;
@@ -112,21 +46,6 @@ struct dm_verity_prefetch_work {
unsigned n_blocks;
};
-static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io)
-{
- return (struct shash_desc *)(io + 1);
-}
-
-static u8 *io_real_digest(struct dm_verity *v, struct dm_verity_io *io)
-{
- return (u8 *)(io + 1) + v->shash_descsize;
-}
-
-static u8 *io_want_digest(struct dm_verity *v, struct dm_verity_io *io)
-{
- return (u8 *)(io + 1) + v->shash_descsize + v->digest_size;
-}
-
/*
* Auxiliary structure appended to each dm-bufio buffer. If the value
* hash_verified is nonzero, hash of the block has been verified.
@@ -173,6 +92,84 @@ static sector_t verity_position_at_level(struct dm_verity *v, sector_t block,
return block >> (level * v->hash_per_block_bits);
}
+/*
+ * Wrapper for crypto_shash_init, which handles verity salting.
+ */
+static int verity_hash_init(struct dm_verity *v, struct shash_desc *desc)
+{
+ int r;
+
+ desc->tfm = v->tfm;
+ desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+ r = crypto_shash_init(desc);
+
+ if (unlikely(r < 0)) {
+ DMERR("crypto_shash_init failed: %d", r);
+ return r;
+ }
+
+ if (likely(v->version >= 1)) {
+ r = crypto_shash_update(desc, v->salt, v->salt_size);
+
+ if (unlikely(r < 0)) {
+ DMERR("crypto_shash_update failed: %d", r);
+ return r;
+ }
+ }
+
+ return 0;
+}
+
+static int verity_hash_update(struct dm_verity *v, struct shash_desc *desc,
+ const u8 *data, size_t len)
+{
+ int r = crypto_shash_update(desc, data, len);
+
+ if (unlikely(r < 0))
+ DMERR("crypto_shash_update failed: %d", r);
+
+ return r;
+}
+
+static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc,
+ u8 *digest)
+{
+ int r;
+
+ if (unlikely(!v->version)) {
+ r = crypto_shash_update(desc, v->salt, v->salt_size);
+
+ if (r < 0) {
+ DMERR("crypto_shash_update failed: %d", r);
+ return r;
+ }
+ }
+
+ r = crypto_shash_final(desc, digest);
+
+ if (unlikely(r < 0))
+ DMERR("crypto_shash_final failed: %d", r);
+
+ return r;
+}
+
+int verity_hash(struct dm_verity *v, struct shash_desc *desc,
+ const u8 *data, size_t len, u8 *digest)
+{
+ int r;
+
+ r = verity_hash_init(v, desc);
+ if (unlikely(r < 0))
+ return r;
+
+ r = verity_hash_update(v, desc, data, len);
+ if (unlikely(r < 0))
+ return r;
+
+ return verity_hash_final(v, desc, digest);
+}
+
static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
sector_t *hash_block, unsigned *offset)
{
@@ -246,17 +243,17 @@ static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
* Verify hash of a metadata block pertaining to the specified data block
* ("block" argument) at a specified level ("level" argument).
*
- * On successful return, io_want_digest(v, io) contains the hash value for
- * a lower tree level or for the data block (if we're at the lowest leve).
+ * On successful return, verity_io_want_digest(v, io) contains the hash value
+ * for a lower tree level or for the data block (if we're at the lowest level).
*
* If "skip_unverified" is true, unverified buffer is skipped and 1 is returned.
* If "skip_unverified" is false, unverified buffer is hashed and verified
- * against current value of io_want_digest(v, io).
+ * against current value of verity_io_want_digest(v, io).
*/
-static int verity_verify_level(struct dm_verity_io *io, sector_t block,
- int level, bool skip_unverified)
+static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
+ sector_t block, int level, bool skip_unverified,
+ u8 *want_digest)
{
- struct dm_verity *v = io->v;
struct dm_buffer *buf;
struct buffer_aux *aux;
u8 *data;
@@ -273,72 +270,128 @@ static int verity_verify_level(struct dm_verity_io *io, sector_t block,
aux = dm_bufio_get_aux_data(buf);
if (!aux->hash_verified) {
- struct shash_desc *desc;
- u8 *result;
-
if (skip_unverified) {
r = 1;
goto release_ret_r;
}
- desc = io_hash_desc(v, io);
- desc->tfm = v->tfm;
- desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
- r = crypto_shash_init(desc);
- if (r < 0) {
- DMERR("crypto_shash_init failed: %d", r);
+ r = verity_hash(v, verity_io_hash_desc(v, io),
+ data, 1 << v->hash_dev_block_bits,
+ verity_io_real_digest(v, io));
+ if (unlikely(r < 0))
goto release_ret_r;
- }
-
- if (likely(v->version >= 1)) {
- r = crypto_shash_update(desc, v->salt, v->salt_size);
- if (r < 0) {
- DMERR("crypto_shash_update failed: %d", r);
- goto release_ret_r;
- }
- }
- r = crypto_shash_update(desc, data, 1 << v->hash_dev_block_bits);
- if (r < 0) {
- DMERR("crypto_shash_update failed: %d", r);
+ if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
+ v->digest_size) == 0))
+ aux->hash_verified = 1;
+ else if (verity_fec_decode(v, io,
+ DM_VERITY_BLOCK_TYPE_METADATA,
+ hash_block, data, NULL) == 0)
+ aux->hash_verified = 1;
+ else if (verity_handle_err(v,
+ DM_VERITY_BLOCK_TYPE_METADATA,
+ hash_block)) {
+ r = -EIO;
goto release_ret_r;
}
+ }
- if (!v->version) {
- r = crypto_shash_update(desc, v->salt, v->salt_size);
- if (r < 0) {
- DMERR("crypto_shash_update failed: %d", r);
- goto release_ret_r;
- }
- }
+ data += offset;
+ memcpy(want_digest, data, v->digest_size);
+ r = 0;
- result = io_real_digest(v, io);
- r = crypto_shash_final(desc, result);
- if (r < 0) {
- DMERR("crypto_shash_final failed: %d", r);
- goto release_ret_r;
- }
- if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) {
- if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_METADATA,
- hash_block)) {
- r = -EIO;
- goto release_ret_r;
- }
- } else
- aux->hash_verified = 1;
+release_ret_r:
+ dm_bufio_release(buf);
+ return r;
+}
+
+/*
+ * Find a hash for a given block, write it to digest and verify the integrity
+ * of the hash tree if necessary.
+ */
+int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
+ sector_t block, u8 *digest, bool *is_zero)
+{
+ int r = 0, i;
+
+ if (likely(v->levels)) {
+ /*
+ * First, we try to get the requested hash for
+ * the current block. If the hash block itself is
+ * verified, zero is returned. If it isn't, this
+ * function returns 1 and we fall back to whole
+ * chain verification.
+ */
+ r = verity_verify_level(v, io, block, 0, true, digest);
+ if (likely(r <= 0))
+ goto out;
}
- data += offset;
+ memcpy(digest, v->root_digest, v->digest_size);
- memcpy(io_want_digest(v, io), data, v->digest_size);
+ for (i = v->levels - 1; i >= 0; i--) {
+ r = verity_verify_level(v, io, block, i, false, digest);
+ if (unlikely(r))
+ goto out;
+ }
+out:
+ if (!r && v->zero_digest)
+ *is_zero = !memcmp(v->zero_digest, digest, v->digest_size);
+ else
+ *is_zero = false;
+
+ return r;
+}
+
+/*
+ * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec
+ * starting from iter.
+ */
+int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
+ struct bvec_iter *iter,
+ int (*process)(struct dm_verity *v,
+ struct dm_verity_io *io, u8 *data,
+ size_t len))
+{
+ unsigned todo = 1 << v->data_dev_block_bits;
+ struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size);
+
+ do {
+ int r;
+ u8 *page;
+ unsigned len;
+ struct bio_vec bv = bio_iter_iovec(bio, *iter);
+
+ page = kmap_atomic(bv.bv_page);
+ len = bv.bv_len;
+
+ if (likely(len >= todo))
+ len = todo;
+
+ r = process(v, io, page + bv.bv_offset, len);
+ kunmap_atomic(page);
+
+ if (r < 0)
+ return r;
+
+ bio_advance_iter(bio, iter, len);
+ todo -= len;
+ } while (todo);
- dm_bufio_release(buf);
return 0;
+}
-release_ret_r:
- dm_bufio_release(buf);
+static int verity_bv_hash_update(struct dm_verity *v, struct dm_verity_io *io,
+ u8 *data, size_t len)
+{
+ return verity_hash_update(v, verity_io_hash_desc(v, io), data, len);
+}
- return r;
+static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
+ u8 *data, size_t len)
+{
+ memset(data, 0, len);
+ return 0;
}
/*
@@ -346,99 +399,56 @@ static int verity_verify_level(struct dm_verity_io *io, sector_t block,
*/
static int verity_verify_io(struct dm_verity_io *io)
{
+ bool is_zero;
struct dm_verity *v = io->v;
- struct bio *bio = dm_bio_from_per_bio_data(io,
- v->ti->per_bio_data_size);
+ struct bvec_iter start;
unsigned b;
- int i;
for (b = 0; b < io->n_blocks; b++) {
- struct shash_desc *desc;
- u8 *result;
int r;
- unsigned todo;
+ struct shash_desc *desc = verity_io_hash_desc(v, io);
+
+ r = verity_hash_for_block(v, io, io->block + b,
+ verity_io_want_digest(v, io),
+ &is_zero);
+ if (unlikely(r < 0))
+ return r;
- if (likely(v->levels)) {
+ if (is_zero) {
/*
- * First, we try to get the requested hash for
- * the current block. If the hash block itself is
- * verified, zero is returned. If it isn't, this
- * function returns 0 and we fall back to whole
- * chain verification.
+ * If we expect a zero block, don't validate, just
+ * return zeros.
*/
- int r = verity_verify_level(io, io->block + b, 0, true);
- if (likely(!r))
- goto test_block_hash;
- if (r < 0)
+ r = verity_for_bv_block(v, io, &io->iter,
+ verity_bv_zero);
+ if (unlikely(r < 0))
return r;
- }
- memcpy(io_want_digest(v, io), v->root_digest, v->digest_size);
-
- for (i = v->levels - 1; i >= 0; i--) {
- int r = verity_verify_level(io, io->block + b, i, false);
- if (unlikely(r))
- return r;
+ continue;
}
-test_block_hash:
- desc = io_hash_desc(v, io);
- desc->tfm = v->tfm;
- desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
- r = crypto_shash_init(desc);
- if (r < 0) {
- DMERR("crypto_shash_init failed: %d", r);
+ r = verity_hash_init(v, desc);
+ if (unlikely(r < 0))
return r;
- }
-
- if (likely(v->version >= 1)) {
- r = crypto_shash_update(desc, v->salt, v->salt_size);
- if (r < 0) {
- DMERR("crypto_shash_update failed: %d", r);
- return r;
- }
- }
- todo = 1 << v->data_dev_block_bits;
- do {
- u8 *page;
- unsigned len;
- struct bio_vec bv = bio_iter_iovec(bio, io->iter);
-
- page = kmap_atomic(bv.bv_page);
- len = bv.bv_len;
- if (likely(len >= todo))
- len = todo;
- r = crypto_shash_update(desc, page + bv.bv_offset, len);
- kunmap_atomic(page);
-
- if (r < 0) {
- DMERR("crypto_shash_update failed: %d", r);
- return r;
- }
-
- bio_advance_iter(bio, &io->iter, len);
- todo -= len;
- } while (todo);
- if (!v->version) {
- r = crypto_shash_update(desc, v->salt, v->salt_size);
- if (r < 0) {
- DMERR("crypto_shash_update failed: %d", r);
- return r;
- }
- }
+ start = io->iter;
+ r = verity_for_bv_block(v, io, &io->iter, verity_bv_hash_update);
+ if (unlikely(r < 0))
+ return r;
- result = io_real_digest(v, io);
- r = crypto_shash_final(desc, result);
- if (r < 0) {
- DMERR("crypto_shash_final failed: %d", r);
+ r = verity_hash_final(v, desc, verity_io_real_digest(v, io));
+ if (unlikely(r < 0))
return r;
- }
- if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) {
- if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
- io->block + b))
- return -EIO;
- }
+
+ if (likely(memcmp(verity_io_real_digest(v, io),
+ verity_io_want_digest(v, io), v->digest_size) == 0))
+ continue;
+ else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
+ io->block + b, NULL, &start) == 0)
+ continue;
+ else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
+ io->block + b))
+ return -EIO;
}
return 0;
@@ -453,9 +463,10 @@ static void verity_finish_io(struct dm_verity_io *io, int error)
struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size);
bio->bi_end_io = io->orig_bi_end_io;
- bio->bi_private = io->orig_bi_private;
bio->bi_error = error;
+ verity_fec_finish_io(io);
+
bio_endio(bio);
}
@@ -470,7 +481,7 @@ static void verity_end_io(struct bio *bio)
{
struct dm_verity_io *io = bio->bi_private;
- if (bio->bi_error) {
+ if (bio->bi_error && !verity_fec_is_enabled(io->v)) {
verity_finish_io(io, bio->bi_error);
return;
}
@@ -566,7 +577,6 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
io = dm_per_bio_data(bio, ti->per_bio_data_size);
io->v = v;
io->orig_bi_end_io = bio->bi_end_io;
- io->orig_bi_private = bio->bi_private;
io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT);
io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits;
@@ -574,6 +584,8 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
bio->bi_private = io;
io->iter = bio->bi_iter;
+ verity_fec_init_io(io);
+
verity_submit_prefetch(v, io);
generic_make_request(bio);
@@ -588,6 +600,7 @@ static void verity_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
struct dm_verity *v = ti->private;
+ unsigned args = 0;
unsigned sz = 0;
unsigned x;
@@ -614,8 +627,17 @@ static void verity_status(struct dm_target *ti, status_type_t type,
else
for (x = 0; x < v->salt_size; x++)
DMEMIT("%02x", v->salt[x]);
+ if (v->mode != DM_VERITY_MODE_EIO)
+ args++;
+ if (verity_fec_is_enabled(v))
+ args += DM_VERITY_OPTS_FEC;
+ if (v->zero_digest)
+ args++;
+ if (!args)
+ return;
+ DMEMIT(" %u", args);
if (v->mode != DM_VERITY_MODE_EIO) {
- DMEMIT(" 1 ");
+ DMEMIT(" ");
switch (v->mode) {
case DM_VERITY_MODE_LOGGING:
DMEMIT(DM_VERITY_OPT_LOGGING);
@@ -627,6 +649,9 @@ static void verity_status(struct dm_target *ti, status_type_t type,
BUG();
}
}
+ if (v->zero_digest)
+ DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
+ sz = verity_fec_status_table(v, sz, result, maxlen);
break;
}
}
@@ -677,6 +702,7 @@ static void verity_dtr(struct dm_target *ti)
kfree(v->salt);
kfree(v->root_digest);
+ kfree(v->zero_digest);
if (v->tfm)
crypto_free_shash(v->tfm);
@@ -689,9 +715,94 @@ static void verity_dtr(struct dm_target *ti)
if (v->data_dev)
dm_put_device(ti, v->data_dev);
+ verity_fec_dtr(v);
+
kfree(v);
}
+static int verity_alloc_zero_digest(struct dm_verity *v)
+{
+ int r = -ENOMEM;
+ struct shash_desc *desc;
+ u8 *zero_data;
+
+ v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
+
+ if (!v->zero_digest)
+ return r;
+
+ desc = kmalloc(v->shash_descsize, GFP_KERNEL);
+
+ if (!desc)
+ return r; /* verity_dtr will free zero_digest */
+
+ zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL);
+
+ if (!zero_data)
+ goto out;
+
+ r = verity_hash(v, desc, zero_data, 1 << v->data_dev_block_bits,
+ v->zero_digest);
+
+out:
+ kfree(desc);
+ kfree(zero_data);
+
+ return r;
+}
+
+static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
+{
+ int r;
+ unsigned argc;
+ struct dm_target *ti = v->ti;
+ const char *arg_name;
+
+ static struct dm_arg _args[] = {
+ {0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"},
+ };
+
+ r = dm_read_arg_group(_args, as, &argc, &ti->error);
+ if (r)
+ return -EINVAL;
+
+ if (!argc)
+ return 0;
+
+ do {
+ arg_name = dm_shift_arg(as);
+ argc--;
+
+ if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) {
+ v->mode = DM_VERITY_MODE_LOGGING;
+ continue;
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) {
+ v->mode = DM_VERITY_MODE_RESTART;
+ continue;
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
+ r = verity_alloc_zero_digest(v);
+ if (r) {
+ ti->error = "Cannot allocate zero digest";
+ return r;
+ }
+ continue;
+
+ } else if (verity_is_fec_opt_arg(arg_name)) {
+ r = verity_fec_parse_opt_args(as, v, &argc, arg_name);
+ if (r)
+ return r;
+ continue;
+ }
+
+ ti->error = "Unrecognized verity feature request";
+ return -EINVAL;
+ } while (argc && !r);
+
+ return r;
+}
+
/*
* Target parameters:
* <version> The current format is version 1.
@@ -710,18 +821,13 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
struct dm_verity *v;
struct dm_arg_set as;
- const char *opt_string;
- unsigned int num, opt_params;
+ unsigned int num;
unsigned long long num_ll;
int r;
int i;
sector_t hash_position;
char dummy;
- static struct dm_arg _args[] = {
- {0, 1, "Invalid number of feature args"},
- };
-
v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL);
if (!v) {
ti->error = "Cannot allocate verity structure";
@@ -730,6 +836,10 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
ti->private = v;
v->ti = ti;
+ r = verity_fec_ctr_alloc(v);
+ if (r)
+ goto bad;
+
if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) {
ti->error = "Device must be readonly";
r = -EINVAL;
@@ -866,29 +976,9 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
as.argc = argc;
as.argv = argv;
- r = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
- if (r)
+ r = verity_parse_opt_args(&as, v);
+ if (r < 0)
goto bad;
-
- while (opt_params) {
- opt_params--;
- opt_string = dm_shift_arg(&as);
- if (!opt_string) {
- ti->error = "Not enough feature arguments";
- r = -EINVAL;
- goto bad;
- }
-
- if (!strcasecmp(opt_string, DM_VERITY_OPT_LOGGING))
- v->mode = DM_VERITY_MODE_LOGGING;
- else if (!strcasecmp(opt_string, DM_VERITY_OPT_RESTART))
- v->mode = DM_VERITY_MODE_RESTART;
- else {
- ti->error = "Invalid feature arguments";
- r = -EINVAL;
- goto bad;
- }
- }
}
v->hash_per_block_bits =
@@ -938,8 +1028,6 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
goto bad;
}
- ti->per_bio_data_size = roundup(sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2, __alignof__(struct dm_verity_io));
-
/* WQ_UNBOUND greatly improves performance when running on ramdisk */
v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus());
if (!v->verify_wq) {
@@ -948,6 +1036,16 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
goto bad;
}
+ ti->per_bio_data_size = sizeof(struct dm_verity_io) +
+ v->shash_descsize + v->digest_size * 2;
+
+ r = verity_fec_ctr(v);
+ if (r)
+ goto bad;
+
+ ti->per_bio_data_size = roundup(ti->per_bio_data_size,
+ __alignof__(struct dm_verity_io));
+
return 0;
bad:
@@ -958,7 +1056,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
static struct target_type verity_target = {
.name = "verity",
- .version = {1, 2, 0},
+ .version = {1, 3, 0},
.module = THIS_MODULE,
.ctr = verity_ctr,
.dtr = verity_dtr,
diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h
new file mode 100644
index 0000000000000000000000000000000000000000..fb419f422d7316f4e4e120cdb275e5222b3972f5
--- /dev/null
+++ b/drivers/md/dm-verity.h
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ * Copyright (C) 2015 Google, Inc.
+ *
+ * Author: Mikulas Patocka <mpatocka@redhat.com>
+ *
+ * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
+ *
+ * This file is released under the GPLv2.
+ */
+
+#ifndef DM_VERITY_H
+#define DM_VERITY_H
+
+#include "dm-bufio.h"
+#include <linux/device-mapper.h>
+#include <crypto/hash.h>
+
+#define DM_VERITY_MAX_LEVELS 63
+
+enum verity_mode {
+ DM_VERITY_MODE_EIO,
+ DM_VERITY_MODE_LOGGING,
+ DM_VERITY_MODE_RESTART
+};
+
+enum verity_block_type {
+ DM_VERITY_BLOCK_TYPE_DATA,
+ DM_VERITY_BLOCK_TYPE_METADATA
+};
+
+struct dm_verity_fec;
+
+struct dm_verity {
+ struct dm_dev *data_dev;
+ struct dm_dev *hash_dev;
+ struct dm_target *ti;
+ struct dm_bufio_client *bufio;
+ char *alg_name;
+ struct crypto_shash *tfm;
+ u8 *root_digest; /* digest of the root block */
+ u8 *salt; /* salt: its size is salt_size */
+ u8 *zero_digest; /* digest for a zero block */
+ unsigned salt_size;
+ sector_t data_start; /* data offset in 512-byte sectors */
+ sector_t hash_start; /* hash start in blocks */
+ sector_t data_blocks; /* the number of data blocks */
+ sector_t hash_blocks; /* the number of hash blocks */
+ unsigned char data_dev_block_bits; /* log2(data blocksize) */
+ unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
+ unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
+ unsigned char levels; /* the number of tree levels */
+ unsigned char version;
+ unsigned digest_size; /* digest size for the current hash algorithm */
+ unsigned shash_descsize;/* the size of temporary space for crypto */
+ int hash_failed; /* set to 1 if hash of any block failed */
+ enum verity_mode mode; /* mode for handling verification errors */
+ unsigned corrupted_errs;/* Number of errors for corrupted blocks */
+
+ struct workqueue_struct *verify_wq;
+
+ /* starting blocks for each tree level. 0 is the lowest level. */
+ sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
+
+ struct dm_verity_fec *fec; /* forward error correction */
+};
+
+struct dm_verity_io {
+ struct dm_verity *v;
+
+ /* original value of bio->bi_end_io */
+ bio_end_io_t *orig_bi_end_io;
+
+ sector_t block;
+ unsigned n_blocks;
+
+ struct bvec_iter iter;
+
+ struct work_struct work;
+
+ /*
+ * Three variably-size fields follow this struct:
+ *
+ * u8 hash_desc[v->shash_descsize];
+ * u8 real_digest[v->digest_size];
+ * u8 want_digest[v->digest_size];
+ *
+ * To access them use: verity_io_hash_desc(), verity_io_real_digest()
+ * and verity_io_want_digest().
+ */
+};
+
+static inline struct shash_desc *verity_io_hash_desc(struct dm_verity *v,
+ struct dm_verity_io *io)
+{
+ return (struct shash_desc *)(io + 1);
+}
+
+static inline u8 *verity_io_real_digest(struct dm_verity *v,
+ struct dm_verity_io *io)
+{
+ return (u8 *)(io + 1) + v->shash_descsize;
+}
+
+static inline u8 *verity_io_want_digest(struct dm_verity *v,
+ struct dm_verity_io *io)
+{
+ return (u8 *)(io + 1) + v->shash_descsize + v->digest_size;
+}
+
+static inline u8 *verity_io_digest_end(struct dm_verity *v,
+ struct dm_verity_io *io)
+{
+ return verity_io_want_digest(v, io) + v->digest_size;
+}
+
+extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
+ struct bvec_iter *iter,
+ int (*process)(struct dm_verity *v,
+ struct dm_verity_io *io,
+ u8 *data, size_t len));
+
+extern int verity_hash(struct dm_verity *v, struct shash_desc *desc,
+ const u8 *data, size_t len, u8 *digest);
+
+extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
+ sector_t block, u8 *digest, bool *is_zero);
+
+#endif /* DM_VERITY_H */
diff --git a/drivers/md/persistent-data/Kconfig b/drivers/md/persistent-data/Kconfig
index 78c74bb71ba42f11ff5035a5a593ed5732df9791..a53cbc928af1927c1c10d8f79abce0c64a939ed7 100644
--- a/drivers/md/persistent-data/Kconfig
+++ b/drivers/md/persistent-data/Kconfig
@@ -7,12 +7,3 @@ config DM_PERSISTENT_DATA
Library providing immutable on-disk data structure support for
device-mapper targets such as the thin provisioning target.
-config DM_DEBUG_BLOCK_STACK_TRACING
- bool "Keep stack trace of persistent data block lock holders"
- depends on STACKTRACE_SUPPORT && DM_PERSISTENT_DATA
- select STACKTRACE
- ---help---
- Enable this for messages that may help debug problems with the
- block manager locking used by thin provisioning and caching.
-
- If unsure, say N.
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index f2393ba838eb57cfa977228da492814d7dda42af..1e33dd51c21ff766418a30c8f44cff6846a92f55 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -97,10 +97,6 @@ static void __del_holder(struct block_lock *lock, struct task_struct *task)
static int __check_holder(struct block_lock *lock)
{
unsigned i;
-#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
- static struct stack_trace t;
- static stack_entries entries;
-#endif
for (i = 0; i < MAX_HOLDERS; i++) {
if (lock->holders[i] == current) {
@@ -110,12 +106,7 @@ static int __check_holder(struct block_lock *lock)
print_stack_trace(lock->traces + i, 4);
DMERR("subsequent acquisition attempted here:");
- t.nr_entries = 0;
- t.max_entries = MAX_STACK;
- t.entries = entries;
- t.skip = 3;
- save_stack_trace(&t);
- print_stack_trace(&t, 4);
+ dump_stack();
#endif
return -EINVAL;
}
diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index b1ced58eb5e1475b440a15de0e26811fb90b8159..ea3d3b656fd0a1f8f55a0bcb0285bf4a94f6c38d 100644
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -754,12 +754,19 @@ static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
return 0;
}
+static bool need_insert(struct btree_node *node, uint64_t *keys,
+ unsigned level, unsigned index)
+{
+ return ((index >= le32_to_cpu(node->header.nr_entries)) ||
+ (le64_to_cpu(node->keys[index]) != keys[level]));
+}
+
static int insert(struct dm_btree_info *info, dm_block_t root,
uint64_t *keys, void *value, dm_block_t *new_root,
int *inserted)
__dm_written_to_disk(value)
{
- int r, need_insert;
+ int r;
unsigned level, index = -1, last_level = info->levels - 1;
dm_block_t block = root;
struct shadow_spine spine;
@@ -775,10 +782,8 @@ static int insert(struct dm_btree_info *info, dm_block_t root,
goto bad;
n = dm_block_data(shadow_current(&spine));
- need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
- (le64_to_cpu(n->keys[index]) != keys[level]));
- if (need_insert) {
+ if (need_insert(n, keys, level, index)) {
dm_block_t new_tree;
__le64 new_le;
@@ -805,10 +810,8 @@ static int insert(struct dm_btree_info *info, dm_block_t root,
goto bad;
n = dm_block_data(shadow_current(&spine));
- need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
- (le64_to_cpu(n->keys[index]) != keys[level]));
- if (need_insert) {
+ if (need_insert(n, keys, level, index)) {
if (inserted)
*inserted = 1;
diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index fca6dbcf9a4727f85d61f7d161094870f5db24d5..7e44005595c1e77d1982e7e89b1259ddea97bf9a 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -152,12 +152,9 @@ static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
static int brb_pop(struct bop_ring_buffer *brb)
{
- struct block_op *bop;
-
if (brb_empty(brb))
return -ENODATA;
- bop = brb->bops + brb->begin;
brb->begin = brb_next(brb, brb->begin);
return 0;