diff options
Diffstat (limited to 'module/zfs/ddt.c')
| -rw-r--r-- | module/zfs/ddt.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c index 7880a899a..33fea0ba3 100644 --- a/module/zfs/ddt.c +++ b/module/zfs/ddt.c @@ -22,6 +22,7 @@ /* * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2012, 2016 by Delphix. All rights reserved. + * Copyright (c) 2022 by Pawel Jakub Dawidek */ #include <sys/zfs_context.h> @@ -1180,5 +1181,59 @@ ddt_walk(spa_t *spa, ddt_bookmark_t *ddb, ddt_entry_t *dde) return (SET_ERROR(ENOENT)); } +/* + * This function is used by Block Cloning (brt.c) to increase reference + * counter for the DDT entry if the block is already in DDT. + * + * Return false if the block, despite having the D bit set, is not present + * in the DDT. Currently this is not possible but might be in the future. + * See the comment below. + */ +boolean_t +ddt_addref(spa_t *spa, const blkptr_t *bp) +{ + ddt_t *ddt; + ddt_entry_t *dde; + boolean_t result; + + spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER); + ddt = ddt_select(spa, bp); + ddt_enter(ddt); + + dde = ddt_lookup(ddt, bp, B_TRUE); + ASSERT(dde != NULL); + + if (dde->dde_type < DDT_TYPES) { + ddt_phys_t *ddp; + + ASSERT3S(dde->dde_class, <, DDT_CLASSES); + + ddp = &dde->dde_phys[BP_GET_NDVAS(bp)]; + if (ddp->ddp_refcnt == 0) { + /* This should never happen? */ + ddt_phys_fill(ddp, bp); + } + ddt_phys_addref(ddp); + result = B_TRUE; + } else { + /* + * At the time of implementating this if the block has the + * DEDUP flag set it must exist in the DEDUP table, but + * there are many advocates that want ability to remove + * entries from DDT with refcnt=1. If this will happen, + * we may have a block with the DEDUP set, but which doesn't + * have a corresponding entry in the DDT. Be ready. + */ + ASSERT3S(dde->dde_class, ==, DDT_CLASSES); + ddt_remove(ddt, dde); + result = B_FALSE; + } + + ddt_exit(ddt); + spa_config_exit(spa, SCL_ZIO, FTAG); + + return (result); +} + ZFS_MODULE_PARAM(zfs_dedup, zfs_dedup_, prefetch, INT, ZMOD_RW, "Enable prefetching dedup-ed blks"); |