[Devel] [RFC PATCH vz9 v5 40/49] dm-ploop: prepare bat updates under bat_lock
Alexander Atanasov
alexander.atanasov at virtuozzo.com
Mon Nov 18 09:25:07 MSK 2024
Prepare for threads. When preparing bat updates there are two important
things to protect - md->status MD_DIRTY bit and holes bitmap.
Use bat_lock to protect them.
https://virtuozzo.atlassian.net/browse/VSTOR-91821
Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
drivers/md/dm-ploop-map.c | 83 ++++++++++++++++++++++++++++-----------
1 file changed, 61 insertions(+), 22 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 68a973622a25..ba9ad42ead26 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -564,13 +564,18 @@ static bool ploop_md_make_dirty(struct ploop *ploop, struct md_page *md)
unsigned long flags;
bool new = false;
- spin_lock_irqsave(&ploop->bat_lock, flags);
+ /*
+ * Usual pattern is check for dirty, prepare bat update
+ * and then call make_dirty - to avoid races callers must lock
+ */
+
+ lockdep_assert_held(&ploop->bat_lock);
+
WARN_ON_ONCE(test_bit(MD_WRITEBACK, &md->status));
if (!test_and_set_bit(MD_DIRTY, &md->status)) {
llist_add((struct llist_node *)&md->wb_link, &ploop->wb_batch_llist);
new = true;
}
- spin_unlock_irqrestore(&ploop->bat_lock, flags);
md->dirty_timeout = jiffies + ploop->md_submit_delay_ms*HZ/1000;
return new;
@@ -816,6 +821,8 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
dst_clu = piwb->kmpage;
+ /* holes bit map requires bat_lock */
+ spin_lock_irqsave(&ploop->bat_lock, flags);
spin_lock(&md->md_lock);
if (piwb->type == PIWB_TYPE_ALLOC)
goto skip_apply;
@@ -842,6 +849,7 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
clear_bit(MD_WRITEBACK, &md->status);
md->piwb = NULL;
spin_unlock(&md->md_lock);
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
wait_llist_pending = llist_del_all(&md->wait_llist);
if (wait_llist_pending) {
@@ -1099,10 +1107,22 @@ static int ploop_allocate_cluster(struct ploop *ploop, u32 *dst_clu)
u32 clu_size = CLU_SIZE(ploop);
loff_t off, pos, end, old_size;
struct file *file = top->file;
+ unsigned long flags;
int ret;
- if (ploop_find_dst_clu_bit(ploop, dst_clu) < 0)
+ spin_lock_irqsave(&ploop->bat_lock, flags);
+ if (ploop_find_dst_clu_bit(ploop, dst_clu) < 0) {
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
return -EIO;
+ }
+ /*
+ * Mark clu as used. Find & clear bit must be locked,
+ * since this may be called from different threads.
+ * Note, that set_bit may be made from many places.
+ * We only care to clear what find got. parallel set is ok.
+ */
+ ploop_hole_clear_bit(*dst_clu, ploop);
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
pos = CLU_TO_POS(ploop, *dst_clu);
end = pos + clu_size;
@@ -1116,6 +1136,8 @@ static int ploop_allocate_cluster(struct ploop *ploop, u32 *dst_clu)
else
ret = ploop_zero_range(file, pos, off - pos);
if (ret) {
+ ploop_hole_set_bit(*dst_clu, ploop);
+
if (ret != -EOPNOTSUPP)
PL_ERR("punch/zero area: %d", ret);
else if (ploop->falloc_new_clu)
@@ -1130,18 +1152,15 @@ static int ploop_allocate_cluster(struct ploop *ploop, u32 *dst_clu)
if (end > old_size) {
ret = ploop_truncate_prealloc_safe(ploop, top, end, __func__);
- if (ret)
+ if (ret) {
+ ploop_hole_set_bit(*dst_clu, ploop);
return ret;
+ }
}
if (end > top->file_preallocated_area_start)
top->file_preallocated_area_start = end;
- /*
- * Mark clu as used. Find & clear bit is unlocked,
- * since currently this may be called only from deferred
- * kwork. Note, that set_bit may be made from many places.
- */
- ploop_hole_clear_bit(*dst_clu, ploop);
+
return 0;
}
ALLOW_ERROR_INJECTION(ploop_allocate_cluster, ERRNO);
@@ -1443,15 +1462,21 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow)
page_id = ploop_bat_clu_to_page_nr(clu);
md = ploop_md_page_find(ploop, page_id);
- if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_ALLOC, cow->aux_pio))
+ spin_lock_irqsave(&ploop->bat_lock, flags);
+ /* MD_DIRTY is set and cleared concurrently, do it under bat_lock */
+ if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_ALLOC, cow->aux_pio)) {
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
goto out;
+ }
if (!test_bit(MD_DIRTY, &md->status)) {
- /* MD_DIRTY is set and cleared from this work */
- if (ploop_prepare_bat_update(ploop, md, PIWB_TYPE_ALLOC) < 0)
+ if (ploop_prepare_bat_update(ploop, md, PIWB_TYPE_ALLOC) < 0) {
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
goto err_resource;
+ }
ploop_md_make_dirty(ploop, md);
}
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
piwb = md->piwb;
@@ -1540,32 +1565,38 @@ static bool ploop_locate_new_cluster_and_attach_pio(struct ploop *ploop,
bool attached = false;
u32 page_id;
int err;
+ unsigned long flags;
WARN_ON_ONCE(pio->queue_list_id != PLOOP_LIST_DEFERRED);
- if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_ALLOC, pio))
+ spin_lock_irqsave(&ploop->bat_lock, flags);
+ if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_ALLOC, pio)) {
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
goto out;
+ }
+
if (!test_bit(MD_DIRTY, &md->status)) {
- /* Unlocked since MD_DIRTY is set and cleared from this work */
+ /* Locked since MD_DIRTY is set and cleared concurrently */
page_id = ploop_bat_clu_to_page_nr(clu);
if (ploop_prepare_bat_update(ploop, md, PIWB_TYPE_ALLOC) < 0) {
pio->bi_status = BLK_STS_RESOURCE;
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
goto error;
}
bat_update_prepared = true;
+ ploop_md_make_dirty(ploop, md);
}
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
piwb = md->piwb;
err = ploop_alloc_cluster(ploop, piwb, clu, dst_clu);
if (err) {
pio->bi_status = errno_to_blk_status(err);
+ clear_bit(MD_DIRTY, &md->status);
goto error;
}
- if (bat_update_prepared)
- ploop_md_make_dirty(ploop, md);
-
if (pio->bi_op & REQ_FUA) {
piwb->pio->bi_op |= REQ_FUA;
ploop_attach_end_action(pio, piwb);
@@ -1778,23 +1809,29 @@ static void ploop_process_one_discard_pio(struct ploop *ploop, struct pio *pio)
struct ploop_index_wb *piwb;
struct md_page *md;
map_index_t *to;
+ unsigned long flags;
WARN_ON(ploop->nr_deltas != 1 ||
pio->queue_list_id != PLOOP_LIST_DISCARD);
page_id = ploop_bat_clu_to_page_nr(clu);
md = ploop_md_page_find(ploop, page_id);
- if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_DISCARD, pio))
+ spin_lock_irqsave(&ploop->bat_lock, flags);
+ if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_DISCARD, pio)) {
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
goto out;
+ }
+
if (!test_bit(MD_DIRTY, &md->status)) {
- /* Unlocked since MD_DIRTY is set and cleared from this work */
if (ploop_prepare_bat_update(ploop, md, PIWB_TYPE_DISCARD) < 0) {
pio->bi_status = BLK_STS_RESOURCE;
goto err;
}
bat_update_prepared = true;
+ ploop_md_make_dirty(ploop, md);
}
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
piwb = md->piwb;
@@ -1804,19 +1841,21 @@ static void ploop_process_one_discard_pio(struct ploop *ploop, struct pio *pio)
to = piwb->kmpage;
if (WARN_ON_ONCE(!to[clu])) {
pio->bi_status = BLK_STS_IOERR;
+ clear_bit(MD_DIRTY, &md->status);
goto err;
} else {
WRITE_ONCE(to[clu], 0);
+ spin_lock_irqsave(&piwb->lock, flags);
list_add_tail(&pio->list, &piwb->ready_data_pios);
+ spin_unlock_irqrestore(&piwb->lock, flags);
}
- if (bat_update_prepared)
- ploop_md_make_dirty(ploop, md);
ploop_md_up_prio(ploop, md);
out:
// printk(KERN_ERR "disc:2:%ld\n", pio->seqno);
return;
err:
+ spin_unlock_irqrestore(&ploop->bat_lock, flags);
if (bat_update_prepared)
ploop_break_bat_update(ploop, md);
// printk(KERN_ERR "disc:3:%ld\n", pio->seqno);
--
2.43.0
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