From: Yu Kuai yukuai3@huawei.com
mainline inclusion from mainline-v6.5-rc1 commit 460af1f9d9e62acce4a21f9bd00b5bcd5963bcd4 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8UKFJ CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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bio can be added to plug infinitely, and following writeback test can trigger huge amount of plugged bio:
Test script: modprobe brd rd_nr=4 rd_size=10485760 mdadm -CR /dev/md0 -l10 -n4 /dev/ram[0123] --assume-clean --bitmap=internal echo 0 > /proc/sys/vm/dirty_background_ratio fio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs=1 -iodepth=128 -name=test
Test result: Monitor /sys/block/md0/inflight will found that inflight keep increasing until fio finish writing, after running for about 2 minutes:
[root@fedora ~]# cat /sys/block/md0/inflight 0 4474191
Fix the problem by limiting the number of plugged bio based on the number of copies for original bio.
Signed-off-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20230529131106.2123367-8-yukuai1@huaweicloud.com
Conflicts: Commit 309dca309fc3 ("block: store a block_device pointer in struct bio") changed "mbio->bi_disk" to "mbio->bi_bdev"; Commit 2e94275ed582 ("md/raid1: use rdev in raid1_write_request directly") changed "conf->mirrors[i].rdev" to "rdev"; Signed-off-by: Li Lingfeng lilingfeng3@huawei.com --- drivers/md/raid1-10.c | 9 ++++++++- drivers/md/raid1.c | 2 +- drivers/md/raid10.c | 2 +- 3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c index fef13945aab1..c2f0fbbf92c4 100644 --- a/drivers/md/raid1-10.c +++ b/drivers/md/raid1-10.c @@ -21,6 +21,7 @@ #define IO_MADE_GOOD ((struct bio *)2)
#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2) +#define MAX_PLUG_BIO 32
/* for managing resync I/O pages */ struct resync_pages { @@ -31,6 +32,7 @@ struct resync_pages { struct raid1_plug_cb { struct blk_plug_cb cb; struct bio_list pending; + unsigned int count; };
static void rbio_pool_free(void *rbio, void *data) @@ -128,7 +130,7 @@ static inline void raid1_submit_write(struct bio *bio) }
static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio, - blk_plug_cb_fn unplug) + blk_plug_cb_fn unplug, int copies) { struct raid1_plug_cb *plug = NULL; struct blk_plug_cb *cb; @@ -148,6 +150,11 @@ static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
plug = container_of(cb, struct raid1_plug_cb, cb); bio_list_add(&plug->pending, bio); + if (++plug->count / MAX_PLUG_BIO >= copies) { + list_del(&cb->list); + cb->callback(cb, false); + } +
return true; } diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index fbfc5dcf1a12..ebb7adba44d6 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1528,7 +1528,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio, /* flush_pending_writes() needs access to the rdev so...*/ mbio->bi_disk = (void *)conf->mirrors[i].rdev;
- if (!raid1_add_bio_to_plug(mddev, mbio, raid1_unplug)) { + if (!raid1_add_bio_to_plug(mddev, mbio, raid1_unplug, disks)) { spin_lock_irqsave(&conf->device_lock, flags); bio_list_add(&conf->pending_bio_list, mbio); spin_unlock_irqrestore(&conf->device_lock, flags); diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index cbc199ea7c52..0162dbe17cf3 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1252,7 +1252,7 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
atomic_inc(&r10_bio->remaining);
- if (!raid1_add_bio_to_plug(mddev, mbio, raid10_unplug)) { + if (!raid1_add_bio_to_plug(mddev, mbio, raid10_unplug, conf->copies)) { spin_lock_irqsave(&conf->device_lock, flags); bio_list_add(&conf->pending_bio_list, mbio); spin_unlock_irqrestore(&conf->device_lock, flags);