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 <[email protected]> --- drivers/md/dm-writecache.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) Index: linux-2.6/drivers/md/dm-writecache.c =================================================================== --- linux-2.6.orig/drivers/md/dm-writecache.c 2020-02-23 18:15:56.000000000 +0100 +++ linux-2.6/drivers/md/dm-writecache.c 2020-02-23 18:15:56.000000000 +0100 @@ -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; } -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
