* [PATCH 1/4] btrfs: prepare more slots for checksum shash
2022-07-29 14:59 [PATCH 0/4] Selectable checksum implementation David Sterba
@ 2022-07-29 14:59 ` David Sterba
2022-07-29 14:59 ` [PATCH 2/4] btrfs: assign checksum shash slots on init David Sterba
` (3 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: David Sterba @ 2022-07-29 14:59 UTC (permalink / raw)
To: linux-btrfs; +Cc: David Sterba
There's now one checksum template fs_info::csum_shash that contains
whatever the crypto API decides is the best available implementation. To
allow loading other implementations after mount add more slots and
symbolic names. The slot 0 is always used when calculating checksum,
other slots may be set later or left empty.
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/check-integrity.c | 4 ++--
fs/btrfs/compression.c | 4 ++--
fs/btrfs/ctree.h | 13 ++++++++++++-
fs/btrfs/disk-io.c | 19 ++++++++++---------
fs/btrfs/file-item.c | 4 ++--
fs/btrfs/inode.c | 4 ++--
fs/btrfs/scrub.c | 12 ++++++------
fs/btrfs/sysfs.c | 2 +-
8 files changed, 37 insertions(+), 25 deletions(-)
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 5d20137b7b67..dbabdd01ed66 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -1647,7 +1647,7 @@ static noinline_for_stack int btrfsic_test_for_metadata(
char **datav, unsigned int num_pages)
{
struct btrfs_fs_info *fs_info = state->fs_info;
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
struct btrfs_header *h;
u8 csum[BTRFS_CSUM_SIZE];
unsigned int i;
@@ -1660,7 +1660,7 @@ static noinline_for_stack int btrfsic_test_for_metadata(
if (memcmp(h->fsid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE))
return 1;
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
crypto_shash_init(shash);
for (i = 0; i < num_pages; i++) {
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index f4564f32f6d9..096284cdf2ea 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -147,7 +147,7 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio,
u64 disk_start)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
const u32 csum_size = fs_info->csum_size;
const u32 sectorsize = fs_info->sectorsize;
struct page *page;
@@ -161,7 +161,7 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio,
test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state))
return 0;
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
for (i = 0; i < cb->nr_pages; i++) {
u32 pg_offset;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9c21e214d29e..9f145b59e7d2 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -656,6 +656,13 @@ enum btrfs_exclusive_operation {
BTRFS_EXCLOP_SWAP_ACTIVATE,
};
+enum btrfs_csum_impl {
+ CSUM_DEFAULT,
+ CSUM_GENERIC,
+ CSUM_ACCEL,
+ CSUM_COUNT
+};
+
struct btrfs_fs_info {
u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
unsigned long flags;
@@ -1036,7 +1043,11 @@ struct btrfs_fs_info {
spinlock_t swapfile_pins_lock;
struct rb_root swapfile_pins;
- struct crypto_shash *csum_shash;
+ /*
+ * Templates for checksum calculation, slot 0 is for the currently used
+ * one, other slots are optional for available implementations.
+ */
+ struct crypto_shash *csum_shash[CSUM_COUNT];
/* Type of exclusive operation running, protected by super_lock */
enum btrfs_exclusive_operation exclusive_operation;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index de440ebf5648..dc41db822322 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -100,8 +100,9 @@ void __cold btrfs_end_io_wq_exit(void)
static void btrfs_free_csum_hash(struct btrfs_fs_info *fs_info)
{
- if (fs_info->csum_shash)
- crypto_free_shash(fs_info->csum_shash);
+ for (int i = 0; i < CSUM_COUNT; i++)
+ if (fs_info->csum_shash[i])
+ crypto_free_shash(fs_info->csum_shash[i]);
}
/*
@@ -211,11 +212,11 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result)
struct btrfs_fs_info *fs_info = buf->fs_info;
const int num_pages = num_extent_pages(buf);
const int first_page_part = min_t(u32, PAGE_SIZE, fs_info->nodesize);
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
char *kaddr;
int i;
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
crypto_shash_init(shash);
kaddr = page_address(buf->pages[0]) + offset_in_page(buf->start);
crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
@@ -290,9 +291,9 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
struct btrfs_super_block *disk_sb =
(struct btrfs_super_block *)raw_disk_sb;
char result[BTRFS_CSUM_SIZE];
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
/*
* The super_block structure does not span the whole
@@ -2535,7 +2536,7 @@ static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info, u16 csum_type)
return PTR_ERR(csum_shash);
}
- fs_info->csum_shash = csum_shash;
+ fs_info->csum_shash[CSUM_DEFAULT] = csum_shash;
return 0;
}
@@ -4090,7 +4091,7 @@ static int write_dev_supers(struct btrfs_device *device,
{
struct btrfs_fs_info *fs_info = device->fs_info;
struct address_space *mapping = device->bdev->bd_inode->i_mapping;
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
int i;
int errors = 0;
int ret;
@@ -4099,7 +4100,7 @@ static int write_dev_supers(struct btrfs_device *device,
if (max_mirrors == 0)
max_mirrors = BTRFS_SUPER_MIRROR_MAX;
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
for (i = 0; i < max_mirrors; i++) {
struct page *page;
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index c828f971a346..6e416230733b 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -635,7 +635,7 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
u64 offset, bool one_ordered)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
struct btrfs_ordered_sum *sums;
struct btrfs_ordered_extent *ordered = NULL;
const bool use_page_offsets = (offset == (u64)-1);
@@ -663,7 +663,7 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
sums->bytenr = bio->bi_iter.bi_sector << 9;
index = 0;
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
bio_for_each_segment(bvec, bio, iter) {
if (use_page_offsets)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d50448bf8eed..86885f78c6c6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3344,7 +3344,7 @@ static int check_data_csum(struct inode *inode, struct btrfs_bio *bbio,
u64 start)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
char *kaddr;
u32 len = fs_info->sectorsize;
const u32 csum_size = fs_info->csum_size;
@@ -3358,7 +3358,7 @@ static int check_data_csum(struct inode *inode, struct btrfs_bio *bbio,
csum_expected = ((u8 *)bbio->csum) + offset_sectors * csum_size;
kaddr = kmap_atomic(page);
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
crypto_shash_digest(shash, kaddr + pgoff, len, csum);
kunmap_atomic(kaddr);
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index e7b0323e6efd..cc2ee8b71086 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1786,7 +1786,7 @@ static int scrub_checksum_data(struct scrub_block *sblock)
{
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
u8 csum[BTRFS_CSUM_SIZE];
struct scrub_sector *sector;
char *kaddr;
@@ -1798,7 +1798,7 @@ static int scrub_checksum_data(struct scrub_block *sblock)
kaddr = page_address(sector->page);
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
crypto_shash_init(shash);
/*
@@ -1817,7 +1817,7 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock)
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_header *h;
struct btrfs_fs_info *fs_info = sctx->fs_info;
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
u8 calculated_csum[BTRFS_CSUM_SIZE];
u8 on_disk_csum[BTRFS_CSUM_SIZE];
/*
@@ -1861,7 +1861,7 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock)
BTRFS_UUID_SIZE))
sblock->header_error = 1;
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
crypto_shash_init(shash);
crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
sectorsize - BTRFS_CSUM_SIZE);
@@ -1883,7 +1883,7 @@ static int scrub_checksum_super(struct scrub_block *sblock)
struct btrfs_super_block *s;
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
- SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
+ SHASH_DESC_ON_STACK(shash, fs_info->csum_shash[CSUM_DEFAULT]);
u8 calculated_csum[BTRFS_CSUM_SIZE];
struct scrub_sector *sector;
char *kaddr;
@@ -1904,7 +1904,7 @@ static int scrub_checksum_super(struct scrub_block *sblock)
if (!scrub_check_fsid(s->fsid, sector))
++fail_cor;
- shash->tfm = fs_info->csum_shash;
+ shash->tfm = fs_info->csum_shash[CSUM_DEFAULT];
crypto_shash_init(shash);
crypto_shash_digest(shash, kaddr + BTRFS_CSUM_SIZE,
BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE, calculated_csum);
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 92a1fa8e3da6..caa84d398fec 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -939,7 +939,7 @@ static ssize_t btrfs_checksum_show(struct kobject *kobj,
return sysfs_emit(buf, "%s (%s)\n",
btrfs_super_csum_name(csum_type),
- crypto_shash_driver_name(fs_info->csum_shash));
+ crypto_shash_driver_name(fs_info->csum_shash[CSUM_DEFAULT]));
}
BTRFS_ATTR(, checksum, btrfs_checksum_show);
--
2.36.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 3/4] btrfs: add checksum implementation selection after mount
2022-07-29 14:59 [PATCH 0/4] Selectable checksum implementation David Sterba
2022-07-29 14:59 ` [PATCH 1/4] btrfs: prepare more slots for checksum shash David Sterba
2022-07-29 14:59 ` [PATCH 2/4] btrfs: assign checksum shash slots on init David Sterba
@ 2022-07-29 14:59 ` David Sterba
2022-07-29 14:59 ` [PATCH 4/4] btrfs: sysfs: print all loaded csums implementations David Sterba
2022-07-29 17:00 ` [PATCH 0/4] Selectable checksum implementation Boris Burkov
4 siblings, 0 replies; 7+ messages in thread
From: David Sterba @ 2022-07-29 14:59 UTC (permalink / raw)
To: linux-btrfs; +Cc: David Sterba
The sysfs file /sys/fs/btrfs/FSID/checksum shows the filesystem checksum
and the crypto module implementing it. In the scenario when there's only
the default generic implementation available during mount it's selected,
even if there's an unloaded module with accelerated version.
This happens with sha256 that's often built-in so the crypto API may not
trigger loading the modules and select the fastest implementation. Such
filesystem could be left using in the generic for the whole time.
Remount can't fix that and full umount/mount cycle may be impossible eg.
for a root filesystem.
Allow writing strings to the sysfs checksum file that will trigger
loading the crypto shash again and check if the found module is the
desired one.
Possible values:
- default - select whatever is considered default by crypto subsystem,
either generic or accelerated
- accel - try loading an accelerated implementation (must not contain
"generic" in the name)
- generic - load and select the generic implementation
A typical scenario, assuming sha256 is built-in:
$ mkfs.btrfs --csum sha256
$ lsmod | grep sha256
$ mount /dev /mnt
$ cat ...FSID/checksum
sha256 (sha256-generic)
$ modprobe sha256
$ lsmod | grep sha256
sha256_ssse3
$ echo accel > ...FSID/checksum
sha256 (sha256-ni)
The crypto shash for all slots has the same lifetime as the mount, so
it's not possible to unload the crypto module.
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/sysfs.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 85 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index caa84d398fec..0909f1da425c 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -942,7 +942,91 @@ static ssize_t btrfs_checksum_show(struct kobject *kobj,
crypto_shash_driver_name(fs_info->csum_shash[CSUM_DEFAULT]));
}
-BTRFS_ATTR(, checksum, btrfs_checksum_show);
+static const char csum_impl[][8] = {
+ [CSUM_DEFAULT] = "default",
+ [CSUM_GENERIC] = "generic",
+ [CSUM_ACCEL] = "accel",
+};
+
+static int select_checksum(struct btrfs_fs_info *fs_info, enum btrfs_csum_impl type)
+{
+ /* Already set */
+ if (fs_info->csum_shash[CSUM_DEFAULT] == fs_info->csum_shash[type])
+ return 0;
+
+ /* Allocate new if needed */
+ if (!fs_info->csum_shash[type]) {
+ const u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
+ const char *csum_driver = btrfs_super_csum_driver(csum_type);
+ struct crypto_shash *shash1, *tmp;
+ char full_name[32];
+ u32 mask = 0;
+
+ /*
+ * Generic must be requested explicitly, otherwise it could
+ * be accelerated implementation with highest priority.
+ */
+ scnprintf(full_name, sizeof(full_name), "%s%s", csum_driver,
+ (type == CSUM_GENERIC ? "-generic" : ""));
+
+ shash1 = crypto_alloc_shash(full_name, 0, mask);
+ if (IS_ERR(shash1))
+ return PTR_ERR(shash1);
+
+ /* Accelerated requested but generic found */
+ if (type != CSUM_GENERIC &&
+ strstr(crypto_shash_driver_name(shash1), "generic")) {
+ crypto_free_shash(shash1);
+ return -ENOENT;
+ }
+
+ tmp = cmpxchg(&fs_info->csum_shash[type], NULL, shash1);
+ if (tmp) {
+ /* Something raced in */
+ crypto_free_shash(shash1);
+ }
+ }
+
+ /* Select it */
+ fs_info->csum_shash[CSUM_DEFAULT] = fs_info->csum_shash[type];
+ return 0;
+}
+
+static bool strmatch(const char *buffer, const char *string);
+
+static ssize_t btrfs_checksum_store(struct kobject *kobj,
+ struct kobj_attribute *a,
+ const char *buf, size_t len)
+{
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+
+ if (!fs_info)
+ return -EPERM;
+
+ /* Pick the best available, generic or accelerated */
+ if (strmatch(buf, csum_impl[CSUM_DEFAULT])) {
+ if (fs_info->csum_shash[CSUM_ACCEL]) {
+ fs_info->csum_shash[CSUM_DEFAULT] =
+ fs_info->csum_shash[CSUM_ACCEL];
+ return len;
+ }
+ ASSERT(fs_info->csum_shash[CSUM_GENERIC]);
+ fs_info->csum_shash[CSUM_DEFAULT] = fs_info->csum_shash[CSUM_GENERIC];
+ return len;
+ }
+
+ for (int i = 1; i < CSUM_COUNT; i++) {
+ if (strmatch(buf, csum_impl[i])) {
+ int ret;
+
+ ret = select_checksum(fs_info, i);
+ return ret < 0 ? ret : len;
+ }
+ }
+
+ return -EINVAL;
+}
+BTRFS_ATTR_RW(, checksum, btrfs_checksum_show, btrfs_checksum_store);
static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
struct kobj_attribute *a, char *buf)
--
2.36.1
^ permalink raw reply related [flat|nested] 7+ messages in thread