The commit is pushed to "branch-rh9-5.14.0-427.44.1.vz9.80.x-ovz" and will
appear at g...@bitbucket.org:openvz/vzkernel.git
after rh9-5.14.0-427.44.1.vz9.80.6
------>
commit 6c527ebc75036f82303e4dc20aeff33f4ac44ad0
Author: Alexander Atanasov <alexander.atana...@virtuozzo.com>
Date: Fri Jan 24 17:36:25 2025 +0200
dm-ploop: proplerly access nr_bat_entries
nr_bat_entries are updated while resizing, some places
read it without holding the bat_lock, to ensure a good
value is read use READ_ONCE and WRITE_ONCE when updating.
During grow/resize and shrink pios are suspended and
code waits for all active inflight pios to complete.
https://virtuozzo.atlassian.net/browse/VSTOR-91821
Signed-off-by: Alexander Atanasov <alexander.atana...@virtuozzo.com>
======
Patchset description:
ploop: optimistations and scalling
Ploop processes requsts in a different threads in parallel
where possible which results in significant improvement in
performance and makes further optimistations possible.
Known bugs:
- delayed metadata writeback is not working and is missing error handling
- patch to disable it until fixed
- fast path is not working - causes rcu lockups - patch to disable it
Further improvements:
- optimize md pages lookups
Alexander Atanasov (50):
dm-ploop: md_pages map all pages at creation time
dm-ploop: Use READ_ONCE/WRITE_ONCE to access md page data
dm-ploop: fsync after all pios are sent
dm-ploop: move md status to use proper bitops
dm-ploop: convert wait_list and wb_batch_llist to use lockless lists
dm-ploop: convert enospc handling to use lockless lists
dm-ploop: convert suspended_pios list to use lockless list
dm-ploop: convert the rest of the lists to use llist variant
dm-ploop: combine processing of pios thru prepare list and remove
fsync worker
dm-ploop: move from wq to kthread
dm-ploop: move preparations of pios into the caller from worker
dm-ploop: fast path execution for reads
dm-ploop: do not use a wrapper for set_bit to make a page writeback
dm-ploop: BAT use only one list for writeback
dm-ploop: make md writeback timeout to be per page
dm-ploop: add interface to disable bat writeback delay
dm-ploop: convert wb_batch_list to lockless variant
dm-ploop: convert high_prio to status
dm-ploop: split cow processing into two functions
dm-ploop: convert md page rw lock to spin lock
dm-ploop: convert bat_rwlock to bat_lock spinlock
dm-ploop: prepare bat updates under bat_lock
dm-ploop: make ploop_bat_write_complete ready for parallel pio
completion
dm-ploop: make ploop_submit_metadata_writeback return number of
requests sent
dm-ploop: introduce pio runner threads
dm-ploop: add pio list ids to be used when passing pios to runners
dm-ploop: process pios via runners
dm-ploop: disable metadata writeback delay
dm-ploop: disable fast path
dm-ploop: use lockless lists for chained cow updates list
dm-ploop: use lockless lists for data ready pios
dm-ploop: give runner threads better name
dm-ploop: resize operation - add holes bitmap locking
dm-ploop: remove unnecessary operations
dm-ploop: use filp per thread
dm-ploop: catch if we try to advance pio past bio end
dm-ploop: support REQ_FUA for data pios
dm-ploop: proplerly access nr_bat_entries
dm-ploop: fix locking and improve error handling when submitting pios
dm-ploop: fix how ENOTBLK is handled
dm-ploop: sync when suspended or stopping
dm-ploop: rework bat completion logic
dm-ploop: rework logic in pio processing
dm-ploop: end fsync pios in parallel
dm-ploop: make filespace preallocations async
dm-ploop: resubmit enospc pios from dispatcher thread
dm-ploop: dm-ploop: simplify discard completion
dm-ploop: use GFP_ATOMIC instead of GFP_NOIO
dm-ploop: fix locks used in mixed context
dm-ploop: fix how current flags are managed inside threads
Andrey Zhadchenko (13):
dm-ploop: do not flush after metadata writes
dm-ploop: set IOCB_DSYNC on all FUA requests
dm-ploop: remove extra ploop_cluster_is_in_top_delta()
dm-ploop: introduce per-md page locking
dm-ploop: reduce BAT accesses on discard completion
dm-ploop: simplify llseek
dm-ploop: speed up ploop_prepare_bat_update()
dm-ploop: make new allocations immediately visible in BAT
dm-ploop: drop ploop_cluster_is_in_top_delta()
dm-ploop: do not wait for BAT update for non-FUA requests
dm-ploop: add delay for metadata writeback
dm-ploop: submit all postponed metadata on REQ_OP_FLUSH
dm-ploop: handle REQ_PREFLUSH
Feature: dm-ploop: ploop target driver
---
drivers/md/dm-ploop-cmd.c | 13 +++++++++----
drivers/md/dm-ploop-map.c | 12 ++++++------
2 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c
index 50a23212270d..011d37f8fe3e 100644
--- a/drivers/md/dm-ploop-cmd.c
+++ b/drivers/md/dm-ploop-cmd.c
@@ -465,10 +465,14 @@ static int ploop_process_resize_cmd(struct ploop *ploop,
struct ploop_cmd *cmd)
ploop_hole_set_bit(dst_clu, ploop);
dst_clu--;
}
- swap(ploop->hb_nr, cmd->resize.hb_nr);
+ WRITE_ONCE(ploop->hb_nr, cmd->resize.hb_nr);
} else {
ploop_add_md_pages(ploop, &cmd->resize.md_pages_root);
- swap(ploop->nr_bat_entries, cmd->resize.nr_bat_entries);
+ /*
+ * In some places code reads nr_bat_entries without lock
+ * it is ok for grow but if we do shrink this may be a problem.
+ */
+ WRITE_ONCE(ploop->nr_bat_entries, cmd->resize.nr_bat_entries);
}
spin_unlock_irq(&ploop->bat_lock);
@@ -638,7 +642,7 @@ static int ploop_process_merge_latest_snapshot(struct ploop
*ploop)
int ret = 0;
u32 clu;
- for (clu = 0; clu < ploop->nr_bat_entries; clu++) {
+ for (clu = 0; clu < READ_ONCE(ploop->nr_bat_entries); clu++) {
if (fatal_signal_pending(current)) {
ret = -EINTR;
break;
@@ -974,7 +978,8 @@ static int process_flip_upper_deltas(struct ploop *ploop)
struct md_page *md;
u64 size;
- size = (PLOOP_MAP_OFFSET + ploop->nr_bat_entries) * sizeof(map_index_t);
+ size = (PLOOP_MAP_OFFSET + READ_ONCE(ploop->nr_bat_entries))
+ * sizeof(map_index_t);
bat_clusters = DIV_ROUND_UP(size, CLU_SIZE(ploop));
hb_nr = ploop->hb_nr;
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index a1dcf401409c..3b24778e0894 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -106,14 +106,14 @@ static int ploop_rq_valid(struct ploop *ploop, struct
request *rq)
end_byte = to_bytes(sector) + blk_rq_bytes(rq) - 1;
end_clu = POS_TO_CLU(ploop, end_byte);
- if (unlikely(end_clu >= ploop->nr_bat_entries)) {
+ if (unlikely(end_clu >= READ_ONCE(ploop->nr_bat_entries))) {
/*
* This mustn't happen, since we set max_io_len
* via dm_set_target_max_io_len().
*/
WARN_ONCE(1, "sec=%llu, size=%u, end_clu=%u, nr=%u\n",
sector, blk_rq_bytes(rq),
- end_clu, ploop->nr_bat_entries);
+ end_clu, READ_ONCE(ploop->nr_bat_entries));
return -EINVAL;
}
@@ -824,8 +824,9 @@ static void ploop_advance_local_after_bat_wb(struct ploop
*ploop,
off = piwb->page_id * PAGE_SIZE / sizeof(map_index_t);
off -= PLOOP_MAP_OFFSET;
+ spin_lock_irqsave(&ploop->bat_lock, flags);
/* Last and first index in copied page */
- last = ploop->nr_bat_entries - off;
+ last = READ_ONCE(ploop->nr_bat_entries) - off;
if (last > PAGE_SIZE / sizeof(map_index_t))
last = PAGE_SIZE / sizeof(map_index_t);
i = 0;
@@ -835,7 +836,6 @@ static void ploop_advance_local_after_bat_wb(struct ploop
*ploop,
dst_clu = kmap_local_page(piwb->bat_page);
/* holes bit map requires bat_lock */
- spin_lock_irqsave(&ploop->bat_lock, flags);
spin_lock(&md->md_lock);
#ifdef PLOOP_DELAYWB
if (piwb->type == PIWB_TYPE_ALLOC)
@@ -1023,7 +1023,7 @@ static int ploop_prepare_bat_update(struct ploop *ploop,
struct md_page *md,
off -= PLOOP_MAP_OFFSET;
/* Last and first index in copied page */
- last = ploop->nr_bat_entries - off;
+ last = READ_ONCE(ploop->nr_bat_entries) - off;
if (last > PAGE_SIZE / sizeof(map_index_t)) {
last = PAGE_SIZE / sizeof(map_index_t);
is_last_page = false;
@@ -2431,7 +2431,7 @@ loff_t ploop_llseek_hole(struct dm_target *ti, loff_t
offset, int whence)
clu = SEC_TO_CLU(ploop, to_sector(offset) + ploop->skip_off);
id = U32_MAX;
- while (clu < ploop->nr_bat_entries) {
+ while (clu < READ_ONCE(ploop->nr_bat_entries)) {
if (id != ploop_bat_clu_to_page_nr(clu)) {
id = ploop_bat_clu_to_page_nr(clu);
md = ploop_md_page_find(ploop, id);
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