On 7/15/20 4:30 PM, colyli@xxxxxxx wrote:
From: Coly Li <colyli@xxxxxxx>
In bch_btree_cache_alloc() when CONFIG_BCACHE_DEBUG is configured,
allocate memory for c->verify_ondisk may fail if the bucket size > 8MB,
which will require __get_free_pages() to allocate continuous pages
with order > 11 (the default MAX_ORDER of Linux buddy allocator). Such
over size allocation will fail, and cause 2 problems,
- When CONFIG_BCACHE_DEBUG is configured, bch_btree_verify() does not
work, because c->verify_ondisk is NULL and bch_btree_verify() returns
immediately.
- bch_btree_cache_alloc() will fail due to c->verify_ondisk allocation
failed, then the whole cache device registration fails. And because of
this failure, the first problem of bch_btree_verify() has no chance to
be triggered.
This patch fixes the above problem by two means,
1) If pages allocation of c->verify_ondisk fails, set it to NULL and
returns bch_btree_cache_alloc() with -ENOMEM.
2) When calling __get_free_pages() to allocate c->verify_ondisk pages,
use ilog2(meta_bucket_pages(&c->sb)) to make sure ilog2() will always
generate a pages order <= MAX_ORDER (or CONFIG_FORCE_MAX_ZONEORDER).
Then the buddy system won't directly reject the allocation request.
Signed-off-by: Coly Li <colyli@xxxxxxx>
---
drivers/md/bcache/btree.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
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