dm writecache: do direct write if the cache is full (d53f1faf) · Commits · 戴 / test

If the cache device is full, we do a direct write to the origin device. Note that we must not do it if the written block is already in the cache. Signed-off-by:

Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:

Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-writecache.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -1194,6 +1194,7 @@ read_next_block:
		}
		} else {
		do {
		bool found_entry = false;
		if (writecache_has_error(wc))
		goto unlock_error;
		e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
		@@ -1204,9 +1205,21 @@ read_next_block:
		wc->overwrote_committed = true;
		goto bio_copy;
		}
		found_entry = true;
		}
		e = writecache_pop_from_freelist(wc, (sector_t)-1);
		if (unlikely(!e)) {
		if (!found_entry) {
		e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
		if (e) {
		sector_t next_boundary = read_original_sector(wc, e) - bio->bi_iter.bi_sector;
		BUG_ON(!next_boundary);
		if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
		dm_accept_partial_bio(bio, next_boundary);
		}
		}
		goto unlock_remap_origin;
		}
		writecache_wait_on_freelist(wc);
		continue;
		}

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