From: Mikulas Patocka mpatocka@redhat.com
stable inclusion from stable-5.10.51 commit 1b5918b087b1dd7bf193340f25ca63c50a277638 bugzilla: 175263 https://gitee.com/openeuler/kernel/issues/I4DT6F
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit ee55b92a7391bf871939330f662651b54be51b73 upstream.
Commit d53f1fafec9d086f1c5166436abefdaef30e0363 ("dm writecache: do direct write if the cache is full") changed dm-writecache, so that it writes directly to the origin device if the cache is full. Unfortunately, it doesn't forward flush requests to the origin device, so that there is a bug where flushes are being ignored.
Fix this by adding missing flush forwarding.
For PMEM mode, we fix this bug by disabling direct writes to the origin device, because it performs better.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Fixes: d53f1fafec9d ("dm writecache: do direct write if the cache is full") Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/md/dm-writecache.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index 894b58bbe56e..fa0a03e87cdf 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -1297,8 +1297,12 @@ static int writecache_map(struct dm_target *ti, struct bio *bio) writecache_flush(wc); if (writecache_has_error(wc)) goto unlock_error; + if (unlikely(wc->cleaner)) + goto unlock_remap_origin; goto unlock_submit; } else { + if (dm_bio_get_target_bio_nr(bio)) + goto unlock_remap_origin; writecache_offload_bio(wc, bio); goto unlock_return; } @@ -1377,7 +1381,7 @@ static int writecache_map(struct dm_target *ti, struct bio *bio) } e = writecache_pop_from_freelist(wc, (sector_t)-1); if (unlikely(!e)) { - if (!found_entry) { + if (!WC_MODE_PMEM(wc) && !found_entry) { direct_write: e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING); if (e) { @@ -2483,7 +2487,7 @@ static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv) goto bad; }
- ti->num_flush_bios = 1; + ti->num_flush_bios = WC_MODE_PMEM(wc) ? 1 : 2; ti->flush_supported = true; ti->num_discard_bios = 1;