Ok, because it takes the offset away we're not aligned any more.
I think the right fix is to fix this properly and stop poking into
the bio internals. The patch below has surived and xfstests quick
run on two bcache devices:
---
>From 3bf1068e2dc6a75442513e8f9f64055740c0b507 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Thu, 4 Nov 2021 10:40:37 +0100
Subject: bcache: lift bvec mapping into bch_bio_alloc_pages
Use the proper block APIs to add pages to the bio and remove the need
for the extra call to bch_bio_map and the open coded data copy for the
write case.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/md/bcache/btree.c | 31 ++++++++------------------
drivers/md/bcache/debug.c | 4 +---
drivers/md/bcache/movinggc.c | 7 +++---
drivers/md/bcache/request.c | 5 ++---
drivers/md/bcache/util.c | 41 +++++++++++++++++++++++------------
drivers/md/bcache/util.h | 2 +-
drivers/md/bcache/writeback.c | 7 +++---
7 files changed, 48 insertions(+), 49 deletions(-)
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 93b67b8d31c3d..c435b8f2bca04 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -339,6 +339,7 @@ static void do_btree_node_write(struct btree *b)
{
struct closure *cl = &b->io;
struct bset *i = btree_bset_last(b);
+ size_t size;
BKEY_PADDED(key) k;
i->version = BCACHE_BSET_VERSION;
@@ -349,9 +350,7 @@ static void do_btree_node_write(struct btree *b)
b->bio->bi_end_io = btree_node_write_endio;
b->bio->bi_private = cl;
- b->bio->bi_iter.bi_size = roundup(set_bytes(i), block_bytes(b->c->cache));
b->bio->bi_opf = REQ_OP_WRITE | REQ_META | REQ_FUA;
- bch_bio_map(b->bio, i);
/*
* If we're appending to a leaf node, we don't technically need FUA -
@@ -372,32 +371,20 @@ static void do_btree_node_write(struct btree *b)
SET_PTR_OFFSET(&k.key, 0, PTR_OFFSET(&k.key, 0) +
bset_sector_offset(&b->keys, i));
- if (!bch_bio_alloc_pages(b->bio, __GFP_NOWARN|GFP_NOWAIT)) {
- struct bio_vec *bv;
- void *addr = (void *) ((unsigned long) i & ~(PAGE_SIZE - 1));
- struct bvec_iter_all iter_all;
-
- bio_for_each_segment_all(bv, b->bio, iter_all) {
- memcpy(bvec_virt(bv), addr, PAGE_SIZE);
- addr += PAGE_SIZE;
- }
-
- bch_submit_bbio(b->bio, b->c, &k.key, 0);
-
- continue_at(cl, btree_node_write_done, NULL);
- } else {
- /*
- * No problem for multipage bvec since the bio is
- * just allocated
- */
- b->bio->bi_vcnt = 0;
+ size = roundup(set_bytes(i), block_bytes(b->c->cache));
+ if (bch_bio_alloc_pages(b->bio, i, size,
+ __GFP_NOWARN | GFP_NOWAIT) < 0) {
+ b->bio->bi_iter.bi_size = size;
bch_bio_map(b->bio, i);
-
bch_submit_bbio(b->bio, b->c, &k.key, 0);
closure_sync(cl);
continue_at_nobarrier(cl, __btree_node_write_done, NULL);
+ return;
}
+
+ bch_submit_bbio(b->bio, b->c, &k.key, 0);
+ continue_at(cl, btree_node_write_done, NULL);
}
void __bch_btree_node_write(struct btree *b, struct closure *parent)
diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
index 6230dfdd9286e..ef8ec8090d579 100644
--- a/drivers/md/bcache/debug.c
+++ b/drivers/md/bcache/debug.c
@@ -117,10 +117,8 @@ void bch_data_verify(struct cached_dev *dc, struct bio *bio)
bio_set_dev(check, bio->bi_bdev);
check->bi_opf = REQ_OP_READ;
check->bi_iter.bi_sector = bio->bi_iter.bi_sector;
- check->bi_iter.bi_size = bio->bi_iter.bi_size;
- bch_bio_map(check, NULL);
- if (bch_bio_alloc_pages(check, GFP_NOIO))
+ if (bch_bio_alloc_pages(check, NULL, bio->bi_iter.bi_size, GFP_NOIO))
goto out_put;
submit_bio_wait(check);
diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c
index b9c3d27ec093a..7d94e2ec562a4 100644
--- a/drivers/md/bcache/movinggc.c
+++ b/drivers/md/bcache/movinggc.c
@@ -84,9 +84,7 @@ static void moving_init(struct moving_io *io)
bio_get(bio);
bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
- bio->bi_iter.bi_size = KEY_SIZE(&io->w->key) << 9;
bio->bi_private = &io->cl;
- bch_bio_map(bio, NULL);
}
static void write_moving(struct closure *cl)
@@ -97,6 +95,8 @@ static void write_moving(struct closure *cl)
if (!op->status) {
moving_init(io);
+ io->bio.bio.bi_iter.bi_size = KEY_SIZE(&io->w->key) << 9;
+ bch_bio_map(&io->bio.bio, NULL);
io->bio.bio.bi_iter.bi_sector = KEY_START(&io->w->key);
op->write_prio = 1;
op->bio = &io->bio.bio;
@@ -163,7 +163,8 @@ static void read_moving(struct cache_set *c)
bio_set_op_attrs(bio, REQ_OP_READ, 0);
bio->bi_end_io = read_moving_endio;
- if (bch_bio_alloc_pages(bio, GFP_KERNEL))
+ if (bch_bio_alloc_pages(bio, NULL, KEY_SIZE(&io->w->key) << 9,
+ GFP_KERNEL))
goto err;
trace_bcache_gc_copy(&w->key);
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index d15aae6c51c13..faa89410c7470 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -921,13 +921,12 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
cache_bio->bi_iter.bi_sector = miss->bi_iter.bi_sector;
bio_copy_dev(cache_bio, miss);
- cache_bio->bi_iter.bi_size = s->insert_bio_sectors << 9;
cache_bio->bi_end_io = backing_request_endio;
cache_bio->bi_private = &s->cl;
- bch_bio_map(cache_bio, NULL);
- if (bch_bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO))
+ if (bch_bio_alloc_pages(cache_bio, NULL, s->insert_bio_sectors << 9,
+ __GFP_NOWARN | GFP_NOIO))
goto out_put;
s->cache_miss = miss;
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index ae380bc3992e3..cf627e7eadc10 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -258,6 +258,8 @@ start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset,
/**
* bch_bio_alloc_pages - allocates a single page for each bvec in a bio
* @bio: bio to allocate pages for
+ * @data: if non-NULL copy data from here into the newly allocate pages
+ * @size: size to allocate
* @gfp_mask: flags for allocation
*
* Allocates pages up to @bio->bi_vcnt.
@@ -265,23 +267,34 @@ start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset,
* Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
* freed.
*/
-int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
+int bch_bio_alloc_pages(struct bio *bio, void *data, size_t size, gfp_t gfp)
{
- int i;
- struct bio_vec *bv;
+ struct bvec_iter iter;
+ struct bio_vec bv;
- /*
- * This is called on freshly new bio, so it is safe to access the
- * bvec table directly.
- */
- for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++, i++) {
- bv->bv_page = alloc_page(gfp_mask);
- if (!bv->bv_page) {
- while (--bv >= bio->bi_io_vec)
- __free_page(bv->bv_page);
- return -ENOMEM;
- }
+ BUG_ON(bio->bi_vcnt);
+
+ while (size) {
+ struct page *page = alloc_page(gfp);
+ unsigned int offset = offset_in_page(page);
+ size_t len = min(size, PAGE_SIZE - offset);
+
+ if (!page)
+ goto unwind;
+ if (data)
+ memcpy_to_page(page, offset, data, len);
+ if (bio_add_page(bio, page, offset, len) != len)
+ goto unwind;
+
+ size -= len;
+ data += len;
}
return 0;
+
+unwind:
+ bio_for_each_segment(bv, bio, iter)
+ __free_page(bv.bv_page);
+ bio->bi_vcnt = 0;
+ return -ENOMEM;
}
diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
index 6f3cb7c921303..131d5e874231f 100644
--- a/drivers/md/bcache/util.h
+++ b/drivers/md/bcache/util.h
@@ -557,6 +557,6 @@ static inline unsigned int fract_exp_two(unsigned int x,
}
void bch_bio_map(struct bio *bio, void *base);
-int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask);
+int bch_bio_alloc_pages(struct bio *bio, void *data, size_t size, gfp_t gfp);
#endif /* _BCACHE_UTIL_H */
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index c7560f66dca88..a153e3a1b3b87 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -297,9 +297,7 @@ static void dirty_init(struct keybuf_key *w)
if (!io->dc->writeback_percent)
bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
- bio->bi_iter.bi_size = KEY_SIZE(&w->key) << 9;
bio->bi_private = w;
- bch_bio_map(bio, NULL);
}
static void dirty_io_destructor(struct closure *cl)
@@ -395,6 +393,8 @@ static void write_dirty(struct closure *cl)
*/
if (KEY_DIRTY(&w->key)) {
dirty_init(w);
+ io->bio.bi_iter.bi_size = KEY_SIZE(&w->key) << 9;
+ bch_bio_map(&io->bio, NULL);
bio_set_op_attrs(&io->bio, REQ_OP_WRITE, 0);
io->bio.bi_iter.bi_sector = KEY_START(&w->key);
bio_set_dev(&io->bio, io->dc->bdev);
@@ -513,7 +513,8 @@ static void read_dirty(struct cached_dev *dc)
bio_set_dev(&io->bio, dc->disk.c->cache->bdev);
io->bio.bi_end_io = read_dirty_endio;
- if (bch_bio_alloc_pages(&io->bio, GFP_KERNEL))
+ if (bch_bio_alloc_pages(&io->bio, NULL,
+ KEY_SIZE(&w->key) << 9, GFP_KERNEL))
goto err_free;
trace_bcache_writeback(&w->key);
--
2.30.2
