preerase: Inverted LFS3_PREERASE to be opt-in

The original motivation for making LFS3_PREERASE opt-out, is that it makes sense for LFS3_GBMAP to bring in all gbmap-related features (PREERASE, BADBLOCKS (future)). However, after a bit of use, I think this just complicates our ifdef logic too much. So instead, LFS3_PREERASE is now opt-in, with the intention of making all ifdefs relative only to the default build. I think this will make it easier to reason about ifdefs, at least internally. Eventually, I want to look into alternative default builds (LFS3_BIGGER, LFS3_BIGGERR, ..., LFS3_BIGGEST), which would provide an alternative way to enable all gbmap-related features. Though these builds have a high-risk of bikeshedding (LFS3_GC?), so we'll see. --- That being said, the main ergonomic improvement was probably adding a #error, so we don't have to check ifdef GBMAP everywhere. Maybe this should be extended to LFS3_RDONLY? Or maybe not, LFS3_RDONLY is a bit of a special case. No code changes: code stack ctx before: 35144 2136 660 after: 35144 (+0.0%) 2136 (+0.0%) 660 (+0.0%) code stack ctx gbmap before: 38380 2144 776 gbmap after: 38380 (+0.0%) 2144 (+0.0%) 776 (+0.0%) code stack ctx preerase before: 38920 2168 796 preerase after: 38920 (+0.0%) 2168 (+0.0%) 796 (+0.0%)
2025-12-30 00:28:38 -06:00
parent 1d6fa2e5f1
commit ecd780a313
5 changed files with 74 additions and 112 deletions
@@ -7228,9 +7228,7 @@ static inline bool lfs3_t_islookahead(uint32_t flags) {
 }
 #endif

-#if !defined(LFS3_RDONLY) \
-        && defined(LFS3_GBMAP) \
-        && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 static inline bool lfs3_t_ispreerase(uint32_t flags) {
    return flags & LFS3_T_PREERASE;
 }
@@ -10394,7 +10392,7 @@ static void lfs3_gbmap_init(lfs3_gbmap_t *gbmap) {
    #ifndef LFS3_RDONLY
    gbmap->next = 0;
    #endif
-    #if !defined(LFS3_RDONLY) && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    gbmap->ecksum.cksize = -1;
    gbmap->preeraser.known = 0;
    gbmap->preeraser.count = 0;
@@ -10822,9 +10820,7 @@ static inline bool lfs3_alloc_canlookgbmap(const lfs3_t *lfs3) {
 #endif

 // can we pre-erase?
-#if !defined(LFS3_RDONLY) \
-        && defined(LFS3_GBMAP) \
-        && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 static inline bool lfs3_alloc_canpreerase(const lfs3_t *lfs3) {
    // do we even have a gbmap?
    return lfs3_f_isgbmap(lfs3->flags)
@@ -11041,7 +11037,7 @@ static lfs3_sblock_t lfs3_alloc_findfree(lfs3_t *lfs3,
            // free block in our gbmap?
            if (lfs3->gbmap.next > 0) {
                // found a free block
-                #ifndef LFS3_NO_PREERASE
+                #ifdef LFS3_PREERASE
                if (ecksum_) {
                    *ecksum_ = lfs3->gbmap.ecksum;
                }
@@ -11056,7 +11052,7 @@ static lfs3_sblock_t lfs3_alloc_findfree(lfs3_t *lfs3,
            if (!(lfs3->lookahead.buffer[lfs3->lookahead.off / 8]
                    & (1 << (lfs3->lookahead.off % 8)))) {
                // found a free block
-                #if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+                #ifdef LFS3_PREERASE
                if (ecksum_) {
                    ecksum_->cksize = -1;
                }
@@ -11161,7 +11157,7 @@ static lfs3_sblock_t lfs3_alloc_(lfs3_t *lfs3, uint32_t flags,
        lfs3_ecksum_t *ecksum_) {
    // we need ecksum to be non-null here, hey this is an internal
    // API anyways
-    #if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+    #ifdef LFS3_PREERASE
    LFS3_ASSERT(ecksum_);
    #endif

@@ -11175,10 +11171,10 @@ static lfs3_sblock_t lfs3_alloc_(lfs3_t *lfs3, uint32_t flags,
        // erase requested?
        if (lfs3_alloc_iserase(flags)) {
            // pre-erased?
-            if (LFS3_IFDEF_GBMAP(LFS3_IFDEF_PREERASE(
+            if (LFS3_IFDEF_PREERASE(
                    lfs3_ecksum_isecksum(ecksum_),
-                    false), false)) {
-                #if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+                    false)) {
+                #ifdef LFS3_PREERASE
                // check ecksum
                int err = lfs3_ecksum_ck(lfs3, ecksum_, block, 0);
                if (err && err != LFS3_ERR_CORRUPT) {
@@ -11228,13 +11224,13 @@ static lfs3_sblock_t lfs3_alloc_(lfs3_t *lfs3, uint32_t flags,
 // preerase: caller is responsible for perturbing erased-state
 #ifndef LFS3_RDONLY
 static lfs3_sblock_t lfs3_alloc(lfs3_t *lfs3, uint32_t flags) {
-    #if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+    #ifdef LFS3_PREERASE
    lfs3_ecksum_t ecksum_;
    #endif
    return lfs3_alloc_(lfs3, flags,
-            LFS3_IFDEF_GBMAP(LFS3_IFDEF_PREERASE(
+            LFS3_IFDEF_PREERASE(
                &ecksum_,
-                NULL), NULL));
+                NULL));
 }
 #endif

@@ -11250,18 +11246,18 @@ static int lfs3_alloc_syncgbmap(lfs3_t *lfs3);
 static lfs3_sblock_t lfs3_allocclaim(lfs3_t *lfs3, lfs3_mdir_t *mdir,
        uint32_t flags) {
    (void)mdir;
-    #if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+    #ifdef LFS3_PREERASE
    lfs3_ecksum_t ecksum_;
    #endif
    lfs3_sblock_t block = lfs3_alloc_(lfs3, flags,
-            LFS3_IFDEF_GBMAP(LFS3_IFDEF_PREERASE(
+            LFS3_IFDEF_PREERASE(
                &ecksum_,
-                NULL), NULL));
+                NULL));
    if (block < 0) {
        return block;
    }

-    #if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+    #ifdef LFS3_PREERASE
    // need to claim?
    if (lfs3_ecksum_isecksum(&ecksum_)) {
        LFS3_ASSERT(lfs3_alloc_cansyncgbmap(lfs3));
@@ -11329,7 +11325,7 @@ static int lfs3_alloc_lookgbmap(lfs3_t *lfs3) {
 #endif

 // try to pre-erase _one_ block
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 static int lfs3_alloc_preerase(lfs3_t *lfs3) {
    while (lfs3->gbmap.preeraser.known < lfs3->gbmap.known) {
        // lookup next known block
@@ -15061,8 +15057,7 @@ static int lfs3_init(lfs3_t *lfs3, uint32_t flags,
            LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT)
                | LFS3_GC_CKMETA
                | LFS3_GC_CKDATA)) == 0);
@@ -15973,8 +15968,7 @@ int lfs3_mount(lfs3_t *lfs3, uint32_t flags,
                | LFS3_IFDEF_RDONLY(0, LFS3_M_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_M_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_M_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_M_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_M_COMPACT)
                | LFS3_M_CKMETA
                | LFS3_M_CKDATA)) == 0);
@@ -15982,18 +15976,14 @@ int lfs3_mount(lfs3_t *lfs3, uint32_t flags,
    #ifndef LFS3_RDONLY
    LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_ismkconsistent(flags));
    LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_islookahead(flags));
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_ispreerase(flags));
    #endif
    LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_compact(flags));
    #endif
    // we can't use preerased blocks without revperturb, so this is
    // likely a mistake
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(lfs3_m_isrevperturb(flags) || !lfs3_t_ispreerase(flags));
    #endif

@@ -16024,8 +16014,7 @@ int lfs3_mount(lfs3_t *lfs3, uint32_t flags,
            LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT)
                | LFS3_GC_CKMETA
                | LFS3_GC_CKDATA)) {
@@ -16033,8 +16022,7 @@ int lfs3_mount(lfs3_t *lfs3, uint32_t flags,
                LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT)
                    | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
                    | LFS3_IFDEF_RDONLY(0,
-                        LFS3_IFDEF_GBMAP(
-                            LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0))
+                        LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0))
                    | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT)
                    | LFS3_GC_CKMETA
                    | LFS3_GC_CKDATA));
@@ -16297,16 +16285,13 @@ int lfs3_format(lfs3_t *lfs3, uint32_t flags,
                | LFS3_F_MKCONSISTENT
                | LFS3_F_LOOKAHEAD
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_F_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_F_PREERASE, 0))
                | LFS3_F_COMPACT
                | LFS3_F_CKMETA
                | LFS3_F_CKDATA)) == 0);
    // we can't use preerased blocks without revperturb, so this is
    // likely a mistake
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(lfs3_m_isrevperturb(flags) || !lfs3_t_ispreerase(flags));
    #endif

@@ -16347,8 +16332,7 @@ int lfs3_format(lfs3_t *lfs3, uint32_t flags,
            LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT)
                | LFS3_GC_CKMETA
                | LFS3_GC_CKDATA)) {
@@ -16356,8 +16340,7 @@ int lfs3_format(lfs3_t *lfs3, uint32_t flags,
                LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT)
                    | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
                    | LFS3_IFDEF_RDONLY(0,
-                        LFS3_IFDEF_GBMAP(
-                            LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0))
+                        LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0))
                    | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT)
                    | LFS3_GC_CKMETA
                    | LFS3_GC_CKDATA));
@@ -16409,11 +16392,10 @@ int lfs3_fs_stat(lfs3_t *lfs3, struct lfs3_fsinfo *fsinfo) {
            // on both gc_preerase_count and preerase vs free known
            // windows
            | LFS3_IFDEF_RDONLY(0,
-                LFS3_IFDEF_GBMAP(
                LFS3_IFDEF_PREERASE(
                    (lfs3_alloc_canpreerase(lfs3))
                        ? LFS3_I_PREERASE
-                            : 0, 0), 0));
+                        : 0, 0));

    // return filesystem config, this may come from disk
    fsinfo->block_size = lfs3->cfg->block_size;
@@ -16701,14 +16683,10 @@ static int lfs3_fs_gc_(lfs3_t *lfs3, lfs3_mgc_t *mgc,
        // if we have no pending gc work, can we preerase blocks?
        } else if (LFS3_IFDEF_RDONLY(
                false,
-                LFS3_IFDEF_GBMAP(
                LFS3_IFDEF_PREERASE(
                    lfs3_alloc_canpreerase(lfs3),
-                        false),
                    false))) {
-            #if !defined(LFS3_RDONLY) \
-                    && defined(LFS3_GBMAP) \
-                    && !defined(LFS3_NO_PREERASE)
+            #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
            int err = lfs3_alloc_preerase(lfs3);
            if (err && err != LFS3_ERR_NOENT) {
                return err;
@@ -16752,8 +16730,7 @@ int lfs3_fs_ck(lfs3_t *lfs3, uint32_t flags) {
            LFS3_IFDEF_RDONLY(0, LFS3_CK_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_CK_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_CK_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_CK_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_CK_COMPACT)
                | LFS3_CK_CKMETA
                | LFS3_CK_CKDATA)) == 0);
@@ -16763,9 +16740,7 @@ int lfs3_fs_ck(lfs3_t *lfs3, uint32_t flags) {
            || !lfs3_t_ismkconsistent(flags));
    LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
            || !lfs3_t_islookahead(flags));
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
            || !lfs3_t_ispreerase(flags));
    #endif
@@ -16774,9 +16749,7 @@ int lfs3_fs_ck(lfs3_t *lfs3, uint32_t flags) {
    #endif
    // we can't use preerased blocks without revperturb, so this is
    // likely a mistake
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(lfs3_m_isrevperturb(lfs3->flags)
            || !lfs3_t_ispreerase(flags));
    #endif
@@ -16801,8 +16774,7 @@ int lfs3_fs_gc(lfs3_t *lfs3) {
            LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT)
                | LFS3_GC_CKMETA
                | LFS3_GC_CKDATA)) == 0);
@@ -16811,9 +16783,7 @@ int lfs3_fs_gc(lfs3_t *lfs3) {
            || !lfs3_t_ismkconsistent(lfs3->cfg->gc_flags));
    LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
            || !lfs3_t_islookahead(lfs3->cfg->gc_flags));
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
            || !lfs3_t_ispreerase(lfs3->cfg->gc_flags));
    #endif
@@ -16821,9 +16791,7 @@ int lfs3_fs_gc(lfs3_t *lfs3) {
            || !lfs3_t_compact(lfs3->cfg->gc_flags));
    // we can't use preerased blocks without revperturb, so this is
    // likely a mistake
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(lfs3_m_isrevperturb(lfs3->flags)
            || !lfs3_t_ispreerase(lfs3->cfg->gc_flags));
    #endif
@@ -16844,8 +16812,7 @@ int lfs3_fs_unck(lfs3_t *lfs3, uint32_t flags) {
            LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT)
                | LFS3_GC_CKMETA
                | LFS3_GC_CKDATA)) == 0);
@@ -17085,8 +17052,7 @@ int lfs3_trv_open(lfs3_t *lfs3, lfs3_trv_t *trv, uint32_t flags) {
                | LFS3_IFDEF_RDONLY(0, LFS3_T_MKCONSISTENT)
                | LFS3_IFDEF_RDONLY(0, LFS3_T_LOOKAHEAD)
                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(
-                        LFS3_IFDEF_PREERASE(LFS3_T_PREERASE, 0), 0))
+                    LFS3_IFDEF_PREERASE(LFS3_T_PREERASE, 0))
                | LFS3_IFDEF_RDONLY(0, LFS3_T_COMPACT)
                | LFS3_T_CKMETA
                | LFS3_T_CKDATA)) == 0);
@@ -17096,9 +17062,7 @@ int lfs3_trv_open(lfs3_t *lfs3, lfs3_trv_t *trv, uint32_t flags) {
    #ifndef LFS3_RDONLY
    LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_ismkconsistent(flags));
    LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_islookahead(flags));
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_ispreerase(flags));
    #endif
    LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_compact(flags));
@@ -17110,9 +17074,7 @@ int lfs3_trv_open(lfs3_t *lfs3, lfs3_trv_t *trv, uint32_t flags) {
    LFS3_ASSERT(!lfs3_t_ismtreeonly(flags) || !lfs3_t_isckdata(flags));
    // we can't use preerased blocks without revperturb, so this is
    // likely a mistake
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    LFS3_ASSERT(lfs3_m_isrevperturb(flags) || !lfs3_t_ispreerase(flags));
    #endif

@@ -212,7 +212,7 @@ enum lfs3_type {
 #define LFS3_F_LOOKAHEAD \
                        0x00000200  // Repopulate lookahead/gbmap
 #endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 #define LFS3_F_PREERASE 0x00000400  // Try to pre-erase free blocks
 #endif
 #ifndef LFS3_RDONLY
@@ -232,9 +232,7 @@ enum lfs3_type {
 #define LFS3_F_GC ( \
        LFS3_IFDEF_RDONLY(0, LFS3_F_MKCONSISTENT) \
            | LFS3_IFDEF_RDONLY(0, LFS3_F_LOOKAHEAD) \
-            | LFS3_IFDEF_RDONLY(0, \
-                LFS3_IFDEF_GBMAP( \
-                    LFS3_IFDEF_PREERASE(LFS3_F_PREERASE, 0), 0)) \
+            | LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_F_PREERASE, 0)) \
            | LFS3_IFDEF_RDONLY(0, LFS3_F_COMPACT) \
            | LFS3_F_CKMETA \
            | LFS3_F_CKDATA)
@@ -277,7 +275,7 @@ enum lfs3_type {
 #define LFS3_M_LOOKAHEAD \
                        0x00000200  // Repopulate lookahead/gbmap
 #endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 #define LFS3_M_PREERASE 0x00000400  // Try to pre-erase free blocks
 #endif
 #ifndef LFS3_RDONLY
@@ -293,9 +291,7 @@ enum lfs3_type {
 #define LFS3_M_GC ( \
        LFS3_IFDEF_RDONLY(0, LFS3_M_MKCONSISTENT) \
            | LFS3_IFDEF_RDONLY(0, LFS3_M_LOOKAHEAD) \
-            | LFS3_IFDEF_RDONLY(0, \
-                LFS3_IFDEF_GBMAP( \
-                    LFS3_IFDEF_PREERASE(LFS3_M_PREERASE, 0), 0)) \
+            | LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_M_PREERASE, 0)) \
            | LFS3_IFDEF_RDONLY(0, LFS3_M_COMPACT) \
            | LFS3_M_CKMETA \
            | LFS3_M_CKDATA)
@@ -337,7 +333,7 @@ enum lfs3_type {
 #define LFS3_I_LOOKAHEAD \
                        0x00000200  // Lookahead/gbmap is not full
 #endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 #define LFS3_I_PREERASE 0x00000400  // Blocks can be pre-erased
 #endif
 #ifndef LFS3_RDONLY
@@ -370,7 +366,7 @@ enum lfs3_btype {
 #define LFS3_T_LOOKAHEAD \
                        0x00000200  // Repopulate lookahead/gbmap
 #endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 #define LFS3_T_PREERASE 0x00000400  // Try to pre-erase free blocks
 #endif
 #ifndef LFS3_RDONLY
@@ -395,9 +391,7 @@ enum lfs3_btype {
 #define LFS3_T_GC ( \
        LFS3_IFDEF_RDONLY(0, LFS3_T_MKCONSISTENT) \
            | LFS3_IFDEF_RDONLY(0, LFS3_T_LOOKAHEAD) \
-            | LFS3_IFDEF_RDONLY(0, \
-                LFS3_IFDEF_GBMAP( \
-                    LFS3_IFDEF_PREERASE(LFS3_T_PREERASE, 0), 0)) \
+            | LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_T_PREERASE, 0)) \
            | LFS3_IFDEF_RDONLY(0, LFS3_T_COMPACT) \
            | LFS3_T_CKMETA \
            | LFS3_T_CKDATA)
@@ -411,7 +405,7 @@ enum lfs3_btype {
 #define LFS3_CK_LOOKAHEAD \
                        0x00000200  // Repopulate lookahead/gbmap
 #endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 #define LFS3_CK_PREERASE \
                        0x00000400  // Try to pre-erase free blocks
 #endif
@@ -428,9 +422,7 @@ enum lfs3_btype {
 #define LFS3_CK_GC ( \
        LFS3_IFDEF_RDONLY(0, LFS3_CK_MKCONSISTENT) \
            | LFS3_IFDEF_RDONLY(0, LFS3_CK_LOOKAHEAD) \
-            | LFS3_IFDEF_RDONLY(0, \
-                LFS3_IFDEF_GBMAP( \
-                    LFS3_IFDEF_PREERASE(LFS3_CK_PREERASE, 0), 0)) \
+            | LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_CK_PREERASE, 0)) \
            | LFS3_IFDEF_RDONLY(0, LFS3_CK_COMPACT) \
            | LFS3_CK_CKMETA \
            | LFS3_CK_CKDATA)
@@ -444,7 +436,7 @@ enum lfs3_btype {
 #define LFS3_GC_LOOKAHEAD \
                        0x00000200  // Repopulate lookahead/gbmap
 #endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
 #define LFS3_GC_PREERASE \
                        0x00000400  // Try to pre-erase free blocks
 #endif
@@ -461,9 +453,7 @@ enum lfs3_btype {
 #define LFS3_GC_GC ( \
        LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT) \
            | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD) \
-            | LFS3_IFDEF_RDONLY(0, \
-                LFS3_IFDEF_GBMAP( \
-                    LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0)) \
+            | LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0)) \
            | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT) \
            | LFS3_GC_CKMETA \
            | LFS3_GC_CKDATA)
@@ -625,9 +615,7 @@ struct lfs3_cfg {
    // value >= block_count attempts to pre-erase all known free blocks
    // during gc.
    //
-    #if !defined(LFS3_RDONLY) \
-            && defined(LFS3_GBMAP) \
-            && !defined(LFS3_NO_PREERASE)
+    #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
    lfs3_block_t gc_preerase_count;
    #endif

@@ -1383,7 +1371,7 @@ typedef struct lfs3 {
        #if !defined(LFS3_RDONLY)
        lfs3_sblock_t next;
        #endif
-        #if !defined(LFS3_RDONLY) && !defined(LFS3_NO_PREERASE)
+        #if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
        lfs3_ecksum_t ecksum;
        struct lfs3_preeraser {
            lfs3_block_t known;
@@ -50,6 +50,9 @@
 #ifndef LFS3_GBMAP
 #define LFS3_GBMAP
 #endif
+#ifndef LFS3_PREERASE
+#define LFS3_PREERASE
+#endif
 #ifndef LFS3_BLEAFCACHE
 #define LFS3_BLEAFCACHE
 #endif
@@ -83,6 +86,9 @@
 #ifdef LFS3_YES_GBMAP
 #define LFS3_GBMAP
 #endif
+#ifdef LFS3_YES_PREERASE
+#define LFS3_PREERASE
+#endif
 #ifdef LFS3_YES_BLEAFCACHE
 #define LFS3_BLEAFCACHE
 #endif
@@ -103,6 +109,12 @@
 #endif
 #endif

+// some define dependencies
+#if defined(LFS3_PREERASE) \
+        && (!defined(LFS3_GBMAP) || !defined(LFS3_REVPERTURB))
+#error "LFS3_PREERASE requires LFS3_GBMAP and LFS3_REVPERTURB"
+#endif
+

 // System includes
 #include <stdint.h>
@@ -313,15 +325,15 @@
 #define LFS3_IFYES_GBMAP(a, b, c) (c)
 #endif

-#ifndef LFS3_NO_PREERASE
+#ifdef LFS3_PREERASE
 #define LFS3_IFDEF_PREERASE(a, b) (a)
 #else
 #define LFS3_IFDEF_PREERASE(a, b) (b)
 #endif

-#if !defined(LFS3_NO_PREERASE) && defined(LFS3_YES_PREERASE)
+#if defined(LFS3_PREERASE) && defined(LFS3_YES_PREERASE)
 #define LFS3_IFYES_PREERASE(a, b, c) (a)
-#elif !defined(LFS3_NO_PREERASE)
+#elif defined(LFS3_PREERASE)
 #define LFS3_IFYES_PREERASE(a, b, c) (b)
 #else
 #define LFS3_IFYES_PREERASE(a, b, c) (c)
@@ -165,7 +165,7 @@ void bench_permutation(size_t i, uint32_t *buffer, size_t size);
 #define BENCH_GBMAP_CFG
 #endif

-#if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#ifdef LFS3_PREERASE
 #define BENCH_PREERASE_CFG \
    .gc_preerase_count          = GC_PREERASE_COUNT,
 #else
@@ -156,7 +156,7 @@ void test_permutation(size_t i, uint32_t *buffer, size_t size);
 #define TEST_GBMAP_CFG
 #endif

-#if defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
+#ifdef LFS3_PREERASE
 #define TEST_PREERASE_CFG \
    .gc_preerase_count          = GC_PREERASE_COUNT,
 #else