alloc: Merged LOOKAHEAD+LOOKGBMAP -> single LOOKAHEAD flag

Our flag space is already really packed, and I'm not sure having these
as separate flags is meaningful or useful for users. They both indicate
to repopulate allocators, and most users probably won't care that there
are two subtly different allocators operating under the hood.

There's an argument that LOOKAHEAD not touching disk is a useful
distinction, but in practice you really only need LOOKAHEAD work when
mounted RDWR.

So, merged the behaviors of LOOKAHEAD + LOOKGBMAP such that
LFS3_*_LOOKAHEAD requests repopulation of all allocators based on
gc_lookahead_thresh and gc_lookgbmap_thresh.

In priority order (some notes below):

1. If max(lookahead, gbmap) < gc_lookahead_thresh => repop lookahead
2. If gbmap < gc_lookgbmap_thresh                 => repop gbmap

As a plus, this makes it easier to avoid LFS3_IFDEF_GBMAP mess.

---

It's interesting to note LFS3_*_LOOKAHEAD will still repopulate the
lookahead buffer when the gbmap is present, but only if this would gain
more knowledge than was is currently in the gbmap.

I considered disabling lookahead scans completely when we have a gbmap,
but repopulating the lookahead buffer is still useful if the gbmap is at
risk of exhaustion. This is what gc_lookahead_thresh is for anyways, and
users can set gc_lookahead_thresh=0 if they want to disable this
behavior.

Relatedly, lookahead scans are actually prioritized over gbmap scans
(when they would gain knowledge). In theory this minimizes gc latency,
as gbmap scans risk triggering a full lookahead scan when building the
new gbmap.

---

Code changes minimal:

                 code          stack          ctx
  before:       35152           2136          660
  after:        35152 (+0.0%)   2136 (+0.0%)  660 (+0.0%)

                 code          stack          ctx
  gbmap before: 38076           2136          776
  gbmap after:  38080 (+0.0%)   2136 (+0.0%)  776 (+0.0%)

lfs3.c

@@ -7226,15 +7226,6 @@ static inline bool lfs3_t_islookahead(uint32_t flags) {
     #endif
 }
 
-static inline bool lfs3_t_islookgbmap(uint32_t flags) {
-    (void)flags;
-    #if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-    return flags & LFS3_T_LOOKGBMAP;
-    #else
-    return false;
-    #endif
-}
-
 static inline bool lfs3_t_compactmeta(uint32_t flags) {
     (void)flags;
     #ifndef LFS3_RDONLY
@@ -10259,6 +10250,8 @@ eot:;
 // needed in lfs3_mtree_gc
 static int lfs3_mdir_mkconsistent(lfs3_t *lfs3, lfs3_mdir_t *mdir);
 static inline void lfs3_alloc_ckpoint_(lfs3_t *lfs3);
+static inline bool lfs3_alloc_canlookahead(const lfs3_t *lfs3);
+static inline bool lfs3_alloc_canlookgbmap(const lfs3_t *lfs3);
 static void lfs3_alloc_adopt(lfs3_t *lfs3, lfs3_block_t known);
 static int lfs3_gbmap_zero(lfs3_t *lfs3, lfs3_btree_t *gbmap);
 static int lfs3_gbmap_markbptr(lfs3_t *lfs3, lfs3_btree_t *gbmap,
@@ -10274,49 +10267,57 @@ static lfs3_stag_t lfs3_mtree_gc(lfs3_t *lfs3, lfs3_mgc_t *mgc,
     // start of traversal?
     if (mgc->t.h.mdir.mid == LFS3_MID_MROOTANCHOR) {
         #ifndef LFS3_RDONLY
-        // checkpoint the allocator to maximize any lookahead scans
+        // setup lookahead stuff
-        //
-        // note we try to repopupate even if the lookahead flag isn't
-        // set because there's no real downside
         if (lfs3_t_islookahead(mgc->t.h.flags)
                 && !lfs3_t_ismtreeonly(mgc->t.h.flags)
                 && !lfs3_t_isckpointed(mgc->t.h.flags)) {
-            lfs3_alloc_ckpoint_(lfs3);
+            // create a new gbmap snapshot?
-            // keep our own ckpointed flag clear
-            mgc->t.h.flags &= ~LFS3_t_CKPOINTED & ~LFS3_t_DIRTY;
-        }
-        #endif
-
-        #if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-        // create a new gbmap snapshot
-        //
-        // note we _don't_ try to repopulate if the lookgbmap flag isn't
-        // set because repopulating the gbmap requires disk writes and
-        // is potentially destructive
-        //
-        // note because we bail as soon as a ckpoint is triggered
-        // (lfs3_t_isckpointed), we don't need to include this snapshot
-        // in traversals, the ckpointed flag also means we don't need to
-        // worry about this repopulation condition becoming true later
-        if (lfs3_t_islookgbmap(mgc->t.h.flags)
-                && lfs3_f_isgbmap(lfs3->flags)
-                && lfs3_t_islookgbmap(lfs3->flags)
-                && !lfs3_t_ismtreeonly(mgc->t.h.flags)
-                && !lfs3_t_isckpointed(mgc->t.h.flags)) {
-            // at least checkpoint the lookahead buffer
-            lfs3_alloc_ckpoint_(lfs3);
-
-            // create a copy of the gbmap
-            mgc->gbmap_ = lfs3->gbmap.b;
-
-            // mark any in-use blocks as free
             //
-            // we do this instead of creating a new gbmap to (1) preserve any
+            // unfortunate it's not really possible to repopulate both
-            // erased/bad info and (2) try to best use any available
+            // the lookahead buffer and gbmap at the same time, so
-            // erased-state
+            // decide on one here
-            int err = lfs3_gbmap_zero(lfs3, &mgc->gbmap_);
+            if (LFS3_IFDEF_GBMAP(
-            if (err) {
+                    lfs3_f_isgbmap(lfs3->flags)
-                return err;
+                        // don't try to repopulate if above
+                        // gc_lookgbmap_thresh, unlike the lookahead
+                        // buffer, repopulating the gbmap writes to
+                        // disk!
+                        && lfs3_alloc_canlookgbmap(lfs3)
+                        // prioritize the lookahead buffer if
+                        // gc_lookahead_thresh is triggered
+                        && !lfs3_alloc_canlookahead(lfs3),
+                    false)) {
+                #ifdef LFS3_GBMAP
+                // lfs3_gbmap_zero may allocate, so checkpoint the
+                // lookahead buffer
+                lfs3_alloc_ckpoint_(lfs3);
+
+                // create a copy of the gbmap
+                mgc->gbmap_ = lfs3->gbmap.b;
+
+                // mark any in-use blocks as free
+                //
+                // we do this instead of creating a new gbmap to
+                // (1) preserve any erased/bad info and (2) try to best
+                // use any available erased-state
+                int err = lfs3_gbmap_zero(lfs3, &mgc->gbmap_);
+                if (err) {
+                    return err;
+                }
+                #endif
+
+            // checkpoint the allocator to maximize any lookahead scans
+            //
+            // note we try to repopulate even if the lookahead flag isn't
+            // set because there's no real downside
+            } else  {
+                lfs3_alloc_ckpoint_(lfs3);
+
+                #ifdef LFS3_GBMAP
+                // use weight=0 to indicate we're populating the
+                // lookahead buffer and not the gbmap
+                mgc->gbmap_.r.weight = 0;
+                #endif
             }
 
             // keep our own ckpointed flag clear
@@ -10337,27 +10338,25 @@ again:;
     }
 
     #ifndef LFS3_RDONLY
-    // mark in-use blocks in lookahead?
+    // mark in-use blocks?
     if (lfs3_t_islookahead(mgc->t.h.flags)
             && !lfs3_t_ismtreeonly(mgc->t.h.flags)
             && !lfs3_t_isckpointed(mgc->t.h.flags)) {
-        lfs3_alloc_markinusebptr(lfs3, tag, bptr_);
+        // mark in-use blocks in gbmap?
-    }
+        if (LFS3_IFDEF_GBMAP(mgc->gbmap_.r.weight != 0, false)) {
+            #ifdef LFS3_GBMAP
+            int err = lfs3_gbmap_markbptr(lfs3, &mgc->gbmap_, tag, bptr_,
+                    LFS3_TAG_BMINUSE);
+            if (err) {
+                return err;
+            }
+            #endif
 
-    // mark in-use blocks in gbmap?
+        // mark in-use blocks in lookahead buffer?
-    #ifdef LFS3_GBMAP
+        } else {
-    if (lfs3_t_islookgbmap(mgc->t.h.flags)
+            lfs3_alloc_markinusebptr(lfs3, tag, bptr_);
-            && lfs3_f_isgbmap(lfs3->flags)
-            && lfs3_t_islookgbmap(lfs3->flags)
-            && !lfs3_t_ismtreeonly(mgc->t.h.flags)
-            && !lfs3_t_isckpointed(mgc->t.h.flags)) {
-        int err = lfs3_gbmap_markbptr(lfs3, &mgc->gbmap_, tag, bptr_,
-                LFS3_TAG_BMINUSE);
-        if (err) {
-            return err;
         }
     }
-    #endif
 
     // mkconsistencing mdirs?
     if (lfs3_t_ismkconsistent(mgc->t.h.flags)
@@ -10419,33 +10418,24 @@ again:;
 
 eot:;
     #ifndef LFS3_RDONLY
-    // was gbmap scan successful?
-    //
-    // this is structured this way because only one repopulation
-    // scan can succeed at a time, if gbmap succeeds it invalidates the
-    // lookahead scan with the new gbmap
-    //
-    // gbmap takes priority because it actually writes to disk
-    if (LFS3_IFDEF_GBMAP(
-            lfs3_t_islookgbmap(mgc->t.h.flags)
-                && lfs3_f_isgbmap(lfs3->flags)
-                && lfs3_t_islookgbmap(lfs3->flags)
-                && !lfs3_t_ismtreeonly(mgc->t.h.flags)
-                && !lfs3_t_isckpointed(mgc->t.h.flags),
-            false)) {
-        #ifdef LFS3_GBMAP
-        int err = lfs3_alloc_adoptgbmap(lfs3, &mgc->gbmap_,
-                lfs3->lookahead.ckpoint);
-        if (err) {
-            return err;
-        }
-        #endif
-
     // was lookahead scan successful?
-    } else if (lfs3_t_islookahead(mgc->t.h.flags)
+    if (lfs3_t_islookahead(mgc->t.h.flags)
             && !lfs3_t_ismtreeonly(mgc->t.h.flags)
             && !lfs3_t_isckpointed(mgc->t.h.flags)) {
-        lfs3_alloc_adopt(lfs3, lfs3->lookahead.ckpoint);
+        // was gbmap scan successful?
+        if (LFS3_IFDEF_GBMAP(mgc->gbmap_.r.weight != 0, false)) {
+            #ifdef LFS3_GBMAP
+            int err = lfs3_alloc_adoptgbmap(lfs3, &mgc->gbmap_,
+                    lfs3->lookahead.ckpoint);
+            if (err) {
+                return err;
+            }
+            #endif
+
+        // was lookahead scan successful?
+        } else {
+            lfs3_alloc_adopt(lfs3, lfs3->lookahead.ckpoint);
+        }
     }
 
     // was mkconsistent successful?
@@ -10793,7 +10783,7 @@ static int lfs3_alloc_lookgbmap(lfs3_t *lfs3);
 //
 // blocks are allocated at most once, and never reallocated, between
 // checkpoints
-#if !defined(LFS3_RDONLY)
+#ifndef LFS3_RDONLY
 static inline int lfs3_alloc_ckpoint(lfs3_t *lfs3) {
     // checkpoint the allocator
     lfs3_alloc_ckpoint_(lfs3);
@@ -10819,9 +10809,19 @@ static inline int lfs3_alloc_ckpoint(lfs3_t *lfs3) {
 #endif
 
 // can we repopulate the lookahead buffer?
-#if !defined(LFS3_RDONLY)
+#ifndef LFS3_RDONLY
 static inline bool lfs3_alloc_canlookahead(const lfs3_t *lfs3) {
-    return lfs3->lookahead.known
+    // below gc_lookahead_thresh?
+    return lfs3_max(
+                lfs3->lookahead.known,
+                // don't bother if we have more information in our
+                // gbmap, in theory the lookahead buffer is rarely used
+                // if a gbmap is present
+                LFS3_IFDEF_GBMAP(
+                    (lfs3_f_isgbmap(lfs3->flags))
+                        ? lfs3->gbmap.known
+                        : 0,
+                    0))
             <= lfs3_min(
                 lfs3->cfg->gc_lookahead_thresh,
                 lfs3_min(
@@ -10831,15 +10831,23 @@ static inline bool lfs3_alloc_canlookahead(const lfs3_t *lfs3) {
 #endif
 
 // can we repopulate the gbmap?
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
+#ifndef LFS3_RDONLY
 static inline bool lfs3_alloc_canlookgbmap(const lfs3_t *lfs3) {
+    #ifdef LFS3_GBMAP
+    // do we even have a gbmap?
     return lfs3_f_isgbmap(lfs3->flags)
+            // below gc_lookgbmap_thresh?
             && lfs3->gbmap.known
                 <= lfs3_min(
                     lfs3_max(
                         lfs3->cfg->gc_lookgbmap_thresh,
                         lfs3->cfg->lookgbmap_thresh),
                     lfs3->block_count-1);
+    #else
+    // TODO adopt this localized void in flag functions?
+    (void)lfs3;
+    return false;
+    #endif
 }
 #endif
 
@@ -10924,8 +10932,13 @@ static void lfs3_alloc_adopt(lfs3_t *lfs3, lfs3_block_t known) {
         LFS3_UNREACHABLE();
     }
 
-    // signal that lookahead is full
+    // signal that lookahead is full, unless we also want a gbmap
-    lfs3->flags &= ~LFS3_I_LOOKAHEAD;
+    if (LFS3_IFDEF_GBMAP(
+            !(lfs3_f_isgbmap(lfs3->flags)
+                && lfs3_alloc_canlookgbmap(lfs3)),
+            true)) {
+        lfs3->flags &= ~LFS3_I_LOOKAHEAD;
+    }
 }
 #endif
 
@@ -10944,7 +10957,7 @@ static int lfs3_alloc_adoptgbmap(lfs3_t *lfs3,
     }
 
     // signal that gbmap is full
-    lfs3->flags &= ~LFS3_I_LOOKGBMAP;
+    lfs3->flags &= ~LFS3_I_LOOKAHEAD;
     return 0;
 }
 #endif
@@ -10978,16 +10991,11 @@ static void lfs3_alloc_inc(lfs3_t *lfs3) {
     }
     #endif
 
-    // signal that lookahead is no longer full
+    // signal that lookahead/gbmap is no longer full
-    if (lfs3_alloc_canlookahead(lfs3)) {
+    if (lfs3_alloc_canlookahead(lfs3)
+            || lfs3_alloc_canlookgbmap(lfs3)) {
         lfs3->flags |= LFS3_I_LOOKAHEAD;
     }
-    #ifdef LFS3_GBMAP
-    // signal that gbmap is no longer full
-    if (lfs3_alloc_canlookgbmap(lfs3)) {
-        lfs3->flags |= LFS3_I_LOOKGBMAP;
-    }
-    #endif
 }
 #endif
 
@@ -15641,14 +15649,15 @@ static int lfs3_mountinited(lfs3_t *lfs3) {
         // known gbmap window
         lfs3->lookahead.window = lfs3->gbmap.window;
 
-        // mark our gbmap as repopulatable if known window is
+        // update lookahead flag, we only signal our gbmap is
-        // <= gc_lookgbmap_thresh
+        // repopulatable if known window <= gc_lookgbmap_thresh,
-        //
+        // unfortunately the way the gbmap feeds itself this rarely
-        // unfortunately the dependency of the gbmap on block allocation
+        // includes the entire disk
-        // means this rarely includes the entire disk
+        lfs3->flags = (lfs3->flags & ~LFS3_I_LOOKAHEAD)
-        if (lfs3_alloc_canlookgbmap(lfs3)) {
+                | ((lfs3_alloc_canlookahead(lfs3)
-            lfs3->flags |= LFS3_I_LOOKGBMAP;
+                        || lfs3_alloc_canlookgbmap(lfs3))
-        }
+                    ? LFS3_I_LOOKAHEAD
+                    : 0);
         #endif
 
     } else {
@@ -15700,9 +15709,6 @@ int lfs3_mount(lfs3_t *lfs3, uint32_t flags,
     #ifdef LFS3_YES_LOOKAHEAD
     flags |= LFS3_M_LOOKAHEAD;
     #endif
-    #ifdef LFS3_YES_LOOKGBMAP
-    flags |= LFS3_M_LOOKGBMAP;
-    #endif
     #ifdef LFS3_YES_COMPACTMETA
     flags |= LFS3_M_COMPACTMETA;
     #endif
@@ -15727,15 +15733,12 @@ int lfs3_mount(lfs3_t *lfs3, uint32_t flags,
                 | LFS3_IFDEF_CKDATACKSUMS(LFS3_M_CKDATACKSUMS, 0)
                 | LFS3_IFDEF_RDONLY(0, LFS3_M_MKCONSISTENT)
                 | LFS3_IFDEF_RDONLY(0, LFS3_M_LOOKAHEAD)
-                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(LFS3_M_LOOKGBMAP, 0))
                 | LFS3_IFDEF_RDONLY(0, LFS3_M_COMPACTMETA)
                 | LFS3_M_CKMETA
                 | LFS3_M_CKDATA)) == 0);
     // these flags require a writable filesystem
     LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_ismkconsistent(flags));
     LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_islookahead(flags));
-    LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_islookgbmap(flags));
     LFS3_ASSERT(!lfs3_m_isrdonly(flags) || !lfs3_t_compactmeta(flags));
 
     int err = lfs3_init(lfs3,
@@ -16004,9 +16007,6 @@ int lfs3_format(lfs3_t *lfs3, uint32_t flags,
     #ifdef LFS3_YES_LOOKAHEAD
     flags |= LFS3_F_LOOKAHEAD;
     #endif
-    #ifdef LFS3_YES_LOOKGBMAP
-    flags |= LFS3_F_LOOKGBMAP;
-    #endif
     #ifdef LFS3_YES_COMPACTMETA
     flags |= LFS3_F_COMPACTMETA;
     #endif
@@ -16029,7 +16029,6 @@ int lfs3_format(lfs3_t *lfs3, uint32_t flags,
                 | LFS3_IFDEF_CKDATACKSUMS(LFS3_F_CKDATACKSUMS, 0)
                 | LFS3_F_MKCONSISTENT
                 | LFS3_F_LOOKAHEAD
-                | LFS3_IFDEF_GBMAP(LFS3_F_LOOKGBMAP, 0)
                 | LFS3_F_COMPACTMETA
                 | LFS3_F_CKMETA
                 | LFS3_F_CKDATA)) == 0);
@@ -16102,7 +16101,6 @@ int lfs3_fs_stat(lfs3_t *lfs3, struct lfs3_fsinfo *fsinfo) {
                 | LFS3_IFDEF_CKDATACKSUMS(LFS3_I_CKDATACKSUMS, 0)
                 | LFS3_IFDEF_RDONLY(0, LFS3_I_MKCONSISTENT)
                 | LFS3_IFDEF_RDONLY(0, LFS3_I_LOOKAHEAD)
-                | LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, 0))
                 | LFS3_IFDEF_RDONLY(0, LFS3_I_COMPACTMETA)
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -16370,9 +16368,6 @@ static int lfs3_fs_gc_(lfs3_t *lfs3, lfs3_mgc_t *mgc,
         #ifndef LFS3_RDONLY
         if (lfs3_t_isckpointed(mgc->t.h.flags)) {
             mgc->t.h.flags &= ~LFS3_T_LOOKAHEAD;
-            #ifdef LFS3_GBMAP
-            mgc->t.h.flags &= ~LFS3_T_LOOKGBMAP;
-            #endif
         }
         #endif
 
@@ -16385,8 +16380,6 @@ static int lfs3_fs_gc_(lfs3_t *lfs3, lfs3_mgc_t *mgc,
         // do we really need a full traversal?
         if (!(mgc->t.h.flags & (
                 LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD)
-                    | LFS3_IFDEF_RDONLY(0,
-                        LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, 0))
                     | LFS3_GC_CKMETA
                     | LFS3_GC_CKDATA))) {
             mgc->t.h.flags |= LFS3_T_MTREEONLY;
@@ -16428,8 +16421,6 @@ 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));
-    LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
-            || !lfs3_t_islookgbmap(flags));
     LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
             || !lfs3_t_compactmeta(flags));
 
@@ -16454,8 +16445,6 @@ 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));
-    LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
-            || !lfs3_t_islookgbmap(lfs3->cfg->gc_flags));
     LFS3_ASSERT(!lfs3_m_isrdonly(lfs3->flags)
             || !lfs3_t_compactmeta(lfs3->cfg->gc_flags));
 
@@ -16707,8 +16696,6 @@ int lfs3_trv_open(lfs3_t *lfs3, lfs3_trv_t *trv, uint32_t flags) {
                 | LFS3_T_EXCL
                 | LFS3_IFDEF_RDONLY(0, LFS3_T_MKCONSISTENT)
                 | LFS3_IFDEF_RDONLY(0, LFS3_T_LOOKAHEAD)
-                | LFS3_IFDEF_RDONLY(0,
-                    LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, 0))
                 | LFS3_IFDEF_RDONLY(0, LFS3_T_COMPACTMETA)
                 | LFS3_T_CKMETA
                 | LFS3_T_CKDATA)) == 0);
@@ -16717,11 +16704,9 @@ int lfs3_trv_open(lfs3_t *lfs3, lfs3_trv_t *trv, uint32_t flags) {
     // these flags require a writable traversal
     LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_ismkconsistent(flags));
     LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_islookahead(flags));
-    LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_islookgbmap(flags));
     LFS3_ASSERT(!lfs3_t_isrdonly(flags) || !lfs3_t_compactmeta(flags));
     // some flags don't make sense when only traversing the mtree
     LFS3_ASSERT(!lfs3_t_ismtreeonly(flags) || !lfs3_t_islookahead(flags));
-    LFS3_ASSERT(!lfs3_t_ismtreeonly(flags) || !lfs3_t_islookgbmap(flags));
     LFS3_ASSERT(!lfs3_t_ismtreeonly(flags) || !lfs3_t_isckdata(flags));
 
     // setup traversal state

lfs3.h

@@ -206,11 +206,7 @@ enum lfs3_type {
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_F_LOOKAHEAD \
-                        0x00001000  // Repopulate lookahead buffer
+                        0x00001000  // Repopulate lookahead/gbmap
-#endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-#define LFS3_F_LOOKGBMAP \
-                        0x00002000  // Repopulate the gbmap
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_F_COMPACTMETA \
@@ -258,11 +254,7 @@ enum lfs3_type {
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_M_LOOKAHEAD \
-                        0x00001000  // Repopulate lookahead buffer
+                        0x00001000  // Repopulate lookahead/gbmap
-#endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-#define LFS3_M_LOOKGBMAP \
-                        0x00002000  // Repopulate the gbmap
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_M_COMPACTMETA \
@@ -305,11 +297,7 @@ enum lfs3_type {
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_I_LOOKAHEAD \
-                        0x00001000  // Lookahead buffer is not full
+                        0x00001000  // Lookahead/gbmap is not full
-#endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-#define LFS3_I_LOOKGBMAP \
-                        0x00002000  // The gbmap is not full
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_I_COMPACTMETA \
@@ -340,11 +328,7 @@ enum lfs3_btype {
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_T_LOOKAHEAD \
-                        0x00001000  // Repopulate lookahead buffer
+                        0x00001000  // Repopulate lookahead/gbmap
-#endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-#define LFS3_T_LOOKGBMAP \
-                        0x00002000  // Repopulate the gbmap
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_T_COMPACTMETA \
@@ -369,11 +353,7 @@ enum lfs3_btype {
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_CK_LOOKAHEAD \
-                        0x00001000  // Repopulate lookahead buffer
+                        0x00001000  // Repopulate lookahead/gbmap
-#endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-#define LFS3_CK_LOOKGBMAP \
-                        0x00002000  // Repopulate the gbmap
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_CK_COMPACTMETA \
@@ -389,11 +369,7 @@ enum lfs3_btype {
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_GC_LOOKAHEAD \
-                        0x00001000  // Repopulate lookahead buffer
+                        0x00001000  // Repopulate lookahead/gbmap
-#endif
-#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP)
-#define LFS3_GC_LOOKGBMAP \
-                        0x00002000  // Repopulate the gbmap
 #endif
 #ifndef LFS3_RDONLY
 #define LFS3_GC_COMPACTMETA \
@@ -406,8 +382,6 @@ enum lfs3_btype {
 #define LFS3_GC_ALL ( \
         LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT) \
             | LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD) \
-            | LFS3_IFDEF_RDONLY(0, \
-                LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, 0)) \
             | LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACTMETA) \
             | LFS3_GC_CKMETA \
             | LFS3_GC_CKDATA)

scripts/dbgflags.py

@@ -83,7 +83,6 @@ F_CKDATACKSUMS  = 0x01000000  # y-  Check data checksums on reads
 
 F_MKCONSISTENT  = 0x00000800  # y-  Make the filesystem consistent
 F_LOOKAHEAD     = 0x00001000  # y-  Repopulate lookahead buffer
-F_LOOKGBMAP     = 0x00002000  # y-  Repopulate the gbmap
 F_COMPACTMETA   = 0x00008000  # y-  Compact metadata logs
 F_CKMETA        = 0x00010000  # y-  Check metadata checksums
 F_CKDATA        = 0x00020000  # y-  Check metadata + data checksums
@@ -103,7 +102,6 @@ M_CKDATACKSUMS  = 0x01000000  # y-  Check data checksums on reads
 
 M_MKCONSISTENT  = 0x00000800  # y-  Make the filesystem consistent
 M_LOOKAHEAD     = 0x00001000  # y-  Repopulate lookahead buffer
-M_LOOKGBMAP     = 0x00002000  # y-  Repopulate the gbmap
 M_COMPACTMETA   = 0x00008000  # y-  Compact metadata logs
 M_CKMETA        = 0x00010000  # y-  Check metadata checksums
 M_CKDATA        = 0x00020000  # y-  Check metadata + data checksums
@@ -111,7 +109,6 @@ M_CKDATA        = 0x00020000  # y-  Check metadata + data checksums
 # File/filesystem check flags
 CK_MKCONSISTENT = 0x00000800  # --  Make the filesystem consistent
 CK_LOOKAHEAD    = 0x00001000  # --  Repopulate lookahead buffer
-CK_LOOKGBMAP    = 0x00002000  # --  Repopulate the gbmap
 CK_COMPACTMETA  = 0x00008000  # --  Compact metadata logs
 CK_CKMETA       = 0x00010000  # --  Check metadata checksums
 CK_CKDATA       = 0x00020000  # --  Check metadata + data checksums
@@ -119,7 +116,6 @@ CK_CKDATA       = 0x00020000  # --  Check metadata + data checksums
 # GC flags
 GC_MKCONSISTENT = 0x00000800  # --  Make the filesystem consistent
 GC_LOOKAHEAD    = 0x00001000  # --  Repopulate lookahead buffer
-GC_LOOKGBMAP    = 0x00002000  # --  Repopulate the gbmap
 GC_COMPACTMETA  = 0x00008000  # --  Compact metadata logs
 GC_CKMETA       = 0x00010000  # --  Check metadata checksums
 GC_CKDATA       = 0x00020000  # --  Check metadata + data checksums
@@ -139,7 +135,6 @@ I_CKDATACKSUMS  = 0x01000000  # --  Mounted with LFS3_M_CKDATACKSUMS
 
 I_MKCONSISTENT  = 0x00000800  # --  Filesystem needs mkconsistent to write
 I_LOOKAHEAD     = 0x00001000  # --  Lookahead buffer is not full
-I_LOOKGBMAP     = 0x00002000  # --  The gbmap is not full
 I_COMPACTMETA   = 0x00008000  # --  Filesystem may have uncompacted metadata
 I_CKMETA        = 0x00010000  # --  Metadata checksums not checked recently
 I_CKDATA        = 0x00020000  # --  Data checksums not checked recently
@@ -152,7 +147,6 @@ T_MTREEONLY     = 0x00000002  # --  Only traverse the mtree
 T_EXCL          = 0x00000008  # --  Error if filesystem modified
 T_MKCONSISTENT  = 0x00000800  # --  Make the filesystem consistent
 T_LOOKAHEAD     = 0x00001000  # --  Repopulate lookahead buffer
-T_LOOKGBMAP     = 0x00002000  # --  Repopulate the gbmap
 T_COMPACTMETA   = 0x00008000  # --  Compact metadata logs
 T_CKMETA        = 0x00010000  # --  Check metadata checksums
 T_CKDATA        = 0x00020000  # --  Check metadata + data checksums

tests/test_gc.toml

@@ -14,7 +14,7 @@ if = '''
 
 
 # test that lookahead can make progress in isolation
-[cases.test_gc_relookahead_progress]
+[cases.test_gc_lookahead_progress]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
@@ -31,6 +31,7 @@ defines.SIZE = [
     '2*BLOCK_SIZE',
     '8*BLOCK_SIZE',
 ]
+if = '!GBMAP'
 ifdef = 'LFS3_GC'
 code = '''
     lfs3_t lfs3;
@@ -83,7 +84,7 @@ code = '''
 '''
 
 # test that lookahead dirtying still works with the GC API
-[cases.test_gc_relookahead_mutation]
+[cases.test_gc_lookahead_mutation]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
@@ -99,8 +100,11 @@ defines.SIZE = [
     '2*BLOCK_SIZE',
     '8*BLOCK_SIZE',
 ]
-# we need something to keep the traversal running
+if = [
-if = 'CKMETA || CKDATA'
+    '!GBMAP',
+    # we need something to keep the traversal running
+    'CKMETA || CKDATA',
+]
 ifdef = 'LFS3_GC'
 code = '''
     lfs3_t lfs3;
@@ -161,10 +165,10 @@ code = '''
     lfs3_unmount(&lfs3) => 0;
 '''
 
-# test that we can relax lookahead repopulation with
+# test that we can relax lookahead scanning with
-# gc_relookahead_thresh
+# gc_lookahead_thresh
-[cases.test_gc_relookahead_relaxed]
+[cases.test_gc_lookahead_relaxed]
-# relax our repop thresh
+# relax our lookahead thresh
 defines.GC_LOOKAHEAD_THRESH = [
     '-1',
     '8*LOOKAHEAD_SIZE - (8*LOOKAHEAD_SIZE/4)',
@@ -179,6 +183,7 @@ defines.GC_FLAGS = '''
 '''
 defines.GC_STEPS = [-1, 1, 2, 10, 100, 1000]
 defines.SIZE = 'BLOCK_SIZE'
+if = '!GBMAP'
 ifdef = 'LFS3_GC'
 code = '''
     lfs3_t lfs3;
@@ -273,14 +278,12 @@ code = '''
 '''
 
 
-# test that regbmap can make progress in isolation
+# test that lookgbmap can make progress in isolation
-[cases.test_gc_regbmap_progress]
+[cases.test_gc_lookgbmap_progress]
-defines.LOOKAHEAD = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
-    LFS3_GC_LOOKGBMAP
+    LFS3_GC_LOOKAHEAD
-        | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
 '''
@@ -317,7 +320,7 @@ code = '''
     // expect dirty initial state or else our test doesn't work
     struct lfs3_fsinfo fsinfo;
     lfs3_fs_stat(&lfs3, &fsinfo) => 0;
-    assert(fsinfo.flags & LFS3_I_LOOKGBMAP);
+    assert(fsinfo.flags & LFS3_I_LOOKAHEAD);
     assert(lfs3.handles != &lfs3.gc.t.h);
 
     // run GC until we make progress
@@ -328,7 +331,7 @@ code = '''
         lfs3_fs_gc(&lfs3) => 0;
 
         lfs3_fs_stat(&lfs3, &fsinfo) => 0;
-        if (!(fsinfo.flags & LFS3_I_LOOKGBMAP)) {
+        if (!(fsinfo.flags & LFS3_I_LOOKAHEAD)) {
             break;
         }
     }
@@ -343,14 +346,12 @@ code = '''
     lfs3_unmount(&lfs3) => 0;
 '''
 
-# test that regbmap dirtying still works with the GC API
+# test that lookgbmap dirtying still works with the GC API
-[cases.test_gc_regbmap_mutation]
+[cases.test_gc_lookgbmap_mutation]
-defines.LOOKAHEAD = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
-    LFS3_GC_LOOKGBMAP
+    LFS3_GC_LOOKAHEAD
-        | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
 '''
@@ -390,7 +391,7 @@ code = '''
     // expect dirty initial state or else our test doesn't work
     struct lfs3_fsinfo fsinfo;
     lfs3_fs_stat(&lfs3, &fsinfo) => 0;
-    assert(fsinfo.flags & LFS3_I_LOOKGBMAP);
+    assert(fsinfo.flags & LFS3_I_LOOKAHEAD);
     assert(lfs3.handles != &lfs3.gc.t.h);
 
     // run GC one step
@@ -413,7 +414,7 @@ code = '''
 
     // we should _not_ make progress
     lfs3_fs_stat(&lfs3, &fsinfo) => 0;
-    assert(fsinfo.flags & LFS3_I_LOOKGBMAP);
+    assert(fsinfo.flags & LFS3_I_LOOKAHEAD);
 
     // check the file contents
     lfs3_file_open(&lfs3, &file, "spider", LFS3_O_RDONLY) => 0;
@@ -425,20 +426,18 @@ code = '''
     lfs3_unmount(&lfs3) => 0;
 '''
 
-# test that we can relax gbmap repopulation with gc_regbmap_thresh
+# test that we can relax gbmap repopulation with gc_lookgbmap_thresh
-[cases.test_gc_regbmap_relaxed]
+[cases.test_gc_lookgbmap_relaxed]
-# relax our repop thresh
+# relax our lookgbmap thresh
 defines.GC_LOOKGBMAP_THRESH = [
     '-1',
     'BLOCK_COUNT - (BLOCK_COUNT/4)',
     'BLOCK_COUNT - (BLOCK_COUNT/2)',
 ]
-defines.LOOKAHEAD = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
-    LFS3_GC_LOOKGBMAP
+    LFS3_GC_LOOKAHEAD
-        | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
 '''
@@ -476,7 +475,7 @@ code = '''
 
         struct lfs3_fsinfo fsinfo;
         lfs3_fs_stat(&lfs3, &fsinfo) => 0;
-        if (!(fsinfo.flags & LFS3_I_LOOKGBMAP)) {
+        if (!(fsinfo.flags & LFS3_I_LOOKAHEAD)) {
             break;
         }
     }
@@ -503,7 +502,7 @@ code = '''
 
         struct lfs3_fsinfo fsinfo;
         lfs3_fs_stat(&lfs3, &fsinfo) => 0;
-        if (fsinfo.flags & LFS3_I_LOOKGBMAP) {
+        if (fsinfo.flags & LFS3_I_LOOKAHEAD) {
             // check that we actually relaxed repopulations
             if ((lfs3_size_t)GC_LOOKGBMAP_THRESH
                     < BLOCK_COUNT-1) {
@@ -524,7 +523,7 @@ code = '''
 
         struct lfs3_fsinfo fsinfo;
         lfs3_fs_stat(&lfs3, &fsinfo) => 0;
-        if (!(fsinfo.flags & LFS3_I_LOOKGBMAP)) {
+        if (!(fsinfo.flags & LFS3_I_LOOKAHEAD)) {
             break;
         }
     }
@@ -1823,14 +1822,12 @@ done:;
 defines.AFTER = [0, 1, 2, 3]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -1849,7 +1846,6 @@ defines.SIZE = [
 if = [
     '(SIZE*N)/BLOCK_SIZE <= 32',
     'LFS3_IFDEF_GC(true, AFTER != 0)',
-    'GBMAP || !LOOKGBMAP',
 ]
 code = '''
     lfs3_t lfs3;
@@ -1888,10 +1884,8 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || (fsinfo.flags & LFS3_I_LOOKAHEAD))
-                | ((GBMAP)
+                    ? LFS3_I_LOOKAHEAD
-                    ? (LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                        & fsinfo.flags)
                     : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
@@ -1914,9 +1908,6 @@ code = '''
             if (!(fsinfo.flags & (
                     ((MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
                         | ((LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                        | ((LOOKGBMAP)
-                            ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            : 0)
                         | ((COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                         | ((CKMETA) ? LFS3_I_CKMETA : 0)
                         | ((CKDATA) ? LFS3_I_CKDATA : 0)))) {
@@ -1946,9 +1937,6 @@ code = '''
             if (!(fsinfo.flags & (
                     ((MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
                         | ((LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                        | ((LOOKGBMAP)
-                            ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            : 0)
                         | ((COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                         | ((CKMETA) ? LFS3_I_CKMETA : 0)
                         | ((CKDATA) ? LFS3_I_CKDATA : 0)))) {
@@ -1975,24 +1963,6 @@ code = '''
                 lfs3_trv_close(&lfs3, &trv) => 0;
             }
 
-            #ifdef LFS3_GBMAP
-            if (LOOKGBMAP && (fsinfo.flags & LFS3_I_LOOKGBMAP)) {
-                // we need an explicit traversal for this
-                lfs3_trv_t trv;
-                lfs3_trv_open(&lfs3, &trv,
-                        LFS3_T_RDWR | LFS3_T_LOOKGBMAP) => 0;
-                while (true) {
-                    struct lfs3_tinfo tinfo;
-                    int err = lfs3_trv_read(&lfs3, &trv, &tinfo);
-                    assert(err == 0 || err == LFS3_ERR_NOENT);
-                    if (err == LFS3_ERR_NOENT) {
-                        break;
-                    }
-                }
-                lfs3_trv_close(&lfs3, &trv) => 0;
-            }
-            #endif
-
             if (COMPACTMETA && (fsinfo.flags & LFS3_I_COMPACTMETA)) {
                 // we need an explicit traversal for this
                 lfs3_trv_t trv;
@@ -2033,12 +2003,9 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD
-                | ((!LOOKGBMAP)
+                        && (!GBMAP || (fsinfo.flags & LFS3_I_LOOKAHEAD)))
-                    ? ((GBMAP)
+                    ? LFS3_I_LOOKAHEAD
-                        ? (LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            & fsinfo.flags)
-                        : 0)
                     : 0)
                 | ((!COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                 // note ckdata implies ckmeta
@@ -2058,14 +2025,12 @@ code = '''
 defines.AFTER = [0, 1, 2, 3]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -2084,7 +2049,6 @@ defines.SIZE = [
 if = [
     '(SIZE*N)/BLOCK_SIZE <= 32',
     'LFS3_IFDEF_GC(true, AFTER != 0)',
-    'GBMAP || !LOOKGBMAP',
 ]
 code = '''
     lfs3_t lfs3;
@@ -2123,10 +2087,8 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || (fsinfo.flags & LFS3_I_LOOKAHEAD))
-                | ((GBMAP)
+                    ? LFS3_I_LOOKAHEAD
-                    ? (LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                        & fsinfo.flags)
                     : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
@@ -2149,9 +2111,6 @@ code = '''
             if (!(fsinfo.flags & (
                     ((MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
                         | ((LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                        | ((LOOKGBMAP)
-                            ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            : 0)
                         | ((COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                         | ((CKMETA) ? LFS3_I_CKMETA : 0)
                         | ((CKDATA) ? LFS3_I_CKDATA : 0)))) {
@@ -2181,9 +2140,6 @@ code = '''
             if (!(fsinfo.flags & (
                     ((MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
                         | ((LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                        | ((LOOKGBMAP)
-                            ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            : 0)
                         | ((COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                         | ((CKMETA) ? LFS3_I_CKMETA : 0)
                         | ((CKDATA) ? LFS3_I_CKDATA : 0)))) {
@@ -2210,24 +2166,6 @@ code = '''
                 lfs3_trv_close(&lfs3, &trv) => 0;
             }
 
-            #ifdef LFS3_GBMAP
-            if (LOOKGBMAP && (fsinfo.flags & LFS3_I_LOOKGBMAP)) {
-                // we need an explicit traversal for this
-                lfs3_trv_t trv;
-                lfs3_trv_open(&lfs3, &trv,
-                        LFS3_T_RDWR | LFS3_T_LOOKGBMAP) => 0;
-                while (true) {
-                    struct lfs3_tinfo tinfo;
-                    int err = lfs3_trv_read(&lfs3, &trv, &tinfo);
-                    assert(err == 0 || err == LFS3_ERR_NOENT);
-                    if (err == LFS3_ERR_NOENT) {
-                        break;
-                    }
-                }
-                lfs3_trv_close(&lfs3, &trv) => 0;
-            }
-            #endif
-
             if (COMPACTMETA && (fsinfo.flags & LFS3_I_COMPACTMETA)) {
                 // we need an explicit traversal for this
                 lfs3_trv_t trv;
@@ -2268,12 +2206,9 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD
-                | ((!LOOKGBMAP)
+                        && (!GBMAP || (fsinfo.flags & LFS3_I_LOOKAHEAD)))
-                    ? ((GBMAP)
+                    ? LFS3_I_LOOKAHEAD
-                        ? (LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            & fsinfo.flags)
-                        : 0)
                     : 0)
                 | ((!COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                 // note ckdata implies ckmeta
@@ -2290,13 +2225,9 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || (fsinfo.flags & LFS3_I_LOOKAHEAD))
-                | ((LOOKGBMAP)
+                    ? LFS3_I_LOOKAHEAD
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1U)
+                    : 0)
-                    : (GBMAP)
-                        ? (LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            & fsinfo.flags)
-                        : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta, but uncking ckdata does
                 // _not_ imply uncking ckmeta
@@ -2320,9 +2251,6 @@ code = '''
             if (!(fsinfo.flags & (
                     ((MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
                         | ((LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                        | ((LOOKGBMAP)
-                            ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            : 0)
                         | ((COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                         | ((CKMETA) ? LFS3_I_CKMETA : 0)
                         | ((CKDATA) ? LFS3_I_CKDATA : 0)))) {
@@ -2352,9 +2280,6 @@ code = '''
             if (!(fsinfo.flags & (
                     ((MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
                         | ((LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                        | ((LOOKGBMAP)
-                            ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            : 0)
                         | ((COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                         | ((CKMETA) ? LFS3_I_CKMETA : 0)
                         | ((CKDATA) ? LFS3_I_CKDATA : 0)))) {
@@ -2381,24 +2306,6 @@ code = '''
                 lfs3_trv_close(&lfs3, &trv) => 0;
             }
 
-            #ifdef LFS3_GBMAP
-            if (LOOKGBMAP && (fsinfo.flags & LFS3_I_LOOKGBMAP)) {
-                // we need an explicit traversal for this
-                lfs3_trv_t trv;
-                lfs3_trv_open(&lfs3, &trv,
-                        LFS3_T_RDWR | LFS3_T_LOOKGBMAP) => 0;
-                while (true) {
-                    struct lfs3_tinfo tinfo;
-                    int err = lfs3_trv_read(&lfs3, &trv, &tinfo);
-                    assert(err == 0 || err == LFS3_ERR_NOENT);
-                    if (err == LFS3_ERR_NOENT) {
-                        break;
-                    }
-                }
-                lfs3_trv_close(&lfs3, &trv) => 0;
-            }
-            #endif
-
             if (COMPACTMETA && (fsinfo.flags & LFS3_I_COMPACTMETA)) {
                 // we need an explicit traversal for this
                 lfs3_trv_t trv;
@@ -2439,12 +2346,9 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD
-                | ((!LOOKGBMAP)
+                        && (!GBMAP || (fsinfo.flags & LFS3_I_LOOKAHEAD)))
-                    ? ((GBMAP)
+                    ? LFS3_I_LOOKAHEAD
-                        ? (LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                            & fsinfo.flags)
-                        : 0)
                     : 0)
                 | ((!COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                 // note ckdata implies ckmeta
@@ -2461,14 +2365,12 @@ code = '''
 defines.N = 100
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -2484,7 +2386,6 @@ defines.SIZE = [
     '2*BLOCK_SIZE',
     '8*BLOCK_SIZE',
 ]
-if = 'GBMAP || !LOOKGBMAP'
 ifdef = 'LFS3_GC'
 code = '''
     lfs3_t lfs3;
@@ -2536,14 +2437,12 @@ code = '''
 defines.N = 100
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -2559,7 +2458,6 @@ defines.SIZE = [
     '2*BLOCK_SIZE',
     '8*BLOCK_SIZE',
 ]
-if = 'GBMAP || !LOOKGBMAP'
 ifdef = 'LFS3_GC'
 code = '''
     lfs3_t lfs3;
@@ -2614,14 +2512,12 @@ code = '''
 [cases.test_gc_nospc]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -2631,7 +2527,6 @@ defines.GC_STEPS = [1, 2, 10, 100, 1000]
 # set compactmeta thresh to minimum
 defines.GC_COMPACTMETA_THRESH = 'BLOCK_SIZE/2'
 defines.SIZE = 'BLOCK_SIZE'
-if = 'GBMAP || !LOOKGBMAP'
 ifdef = 'LFS3_GC'
 code = '''
     lfs3_t lfs3;
@@ -2722,7 +2617,6 @@ code = '''
 [cases.test_gc_spam_dir_many]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -2730,7 +2624,6 @@ defines.UNCK = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -2739,7 +2632,6 @@ defines.GC_STEPS = [-1, 1, 2, 10, 100, 1000]
 # set compactmeta thresh to minimum
 defines.GC_COMPACTMETA_THRESH = 'BLOCK_SIZE/2'
 defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256]
-if = 'GBMAP || !LOOKGBMAP'
 ifdef = 'LFS3_GC'
 code = '''
     // test creating directories
@@ -2832,7 +2724,6 @@ code = '''
 [cases.test_gc_spam_dir_fuzz]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -2840,7 +2731,6 @@ defines.UNCK = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -2852,7 +2742,6 @@ defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256]
 defines.OPS = '2*N'
 defines.SEED = 42
 fuzz = 'SEED'
-if = 'GBMAP || !LOOKGBMAP'
 ifdef = 'LFS3_GC'
 code = '''
     // test fuzz with dirs
@@ -3013,7 +2902,6 @@ code = '''
 [cases.test_gc_spam_file_many]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -3021,7 +2909,6 @@ defines.UNCK = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -3039,10 +2926,7 @@ defines.SIZE = [
     '2*BLOCK_SIZE',
     '4*BLOCK_SIZE',
 ]
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 32'
-    '(SIZE*N)/BLOCK_SIZE <= 32',
-    'GBMAP || !LOOKGBMAP',
-]
 ifdef = 'LFS3_GC'
 code = '''
     // test creating files
@@ -3119,7 +3003,6 @@ code = '''
 [cases.test_gc_spam_file_fuzz]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -3127,7 +3010,6 @@ defines.UNCK = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -3148,10 +3030,7 @@ defines.SIZE = [
 ]
 defines.SEED = 42
 fuzz = 'SEED'
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 16'
-    '(SIZE*N)/BLOCK_SIZE <= 16',
-    'GBMAP || !LOOKGBMAP',
-]
 ifdef = 'LFS3_GC'
 code = '''
     // test fuzz with files
@@ -3364,7 +3243,6 @@ code = '''
 [cases.test_gc_spam_fwrite_fuzz]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -3372,7 +3250,6 @@ defines.UNCK = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -3402,7 +3279,6 @@ if = [
     'CHUNK <= SIZE',
     # this just saves testing time
     'SIZE <= 4*1024*FRAGMENT_SIZE',
-    'GBMAP || !LOOKGBMAP',
 ]
 ifdef = 'LFS3_GC'
 code = '''
@@ -3527,7 +3403,6 @@ code = '''
 [cases.test_gc_spam_uz_fuzz]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -3535,7 +3410,6 @@ defines.UNCK = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -3558,10 +3432,7 @@ defines.SIZE = [
 ]
 defines.SEED = 42
 fuzz = 'SEED'
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 16'
-    '(SIZE*N)/BLOCK_SIZE <= 16',
-    'GBMAP || !LOOKGBMAP',
-]
 ifdef = 'LFS3_GC'
 code = '''
     // test with uncreats, zombies, etc
@@ -3983,7 +3854,6 @@ code = '''
 [cases.test_gc_spam_uzd_fuzz]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -3991,7 +3861,6 @@ defines.UNCK = [false, true]
 defines.GC_FLAGS = '''
     ((MKCONSISTENT) ? LFS3_GC_MKCONSISTENT : 0)
         | ((LOOKAHEAD) ? LFS3_GC_LOOKAHEAD : 0)
-        | ((LOOKGBMAP) ? LFS3_IFDEF_GBMAP(LFS3_GC_LOOKGBMAP, -1) : 0)
         | ((COMPACTMETA) ? LFS3_GC_COMPACTMETA : 0)
         | ((CKMETA) ? LFS3_GC_CKMETA : 0)
         | ((CKDATA) ? LFS3_GC_CKDATA : 0)
@@ -4014,10 +3883,7 @@ defines.SIZE = [
 ]
 defines.SEED = 42
 fuzz = 'SEED'
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 16'
-    '(SIZE*N)/BLOCK_SIZE <= 16',
-    'GBMAP || !LOOKGBMAP',
-]
 ifdef = 'LFS3_GC'
 code = '''
     // test with uncreats, zombies, dirs, etc

tests/test_mount.toml

@@ -1,12 +1,23 @@
 # Advanced mount tests
 after = ['test_mtree', 'test_trvs']
 
+# Test both with and without the gbmap if available
+defines.GBMAP = [false, true]
+if = '''
+    LFS3_IFDEF_YES_GBMAP(
+        GBMAP,
+        LFS3_IFDEF_GBMAP(true, !GBMAP))
+'''
+
 
 # test we can mount
 [cases.test_mount_simple]
 code = '''
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
     lfs3_unmount(&lfs3) => 0;
 '''
@@ -25,7 +36,6 @@ defines.CKMETAPARITY = [false, true]
 defines.CKDATACKSUMS = [false, true]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
@@ -38,13 +48,14 @@ if = [
     'LFS3_IFDEF_CKDATACKSUMS(true, !CKDATACKSUMS)',
     '!RDONLY || !MKCONSISTENT',
     '!RDONLY || !LOOKAHEAD',
-    'LFS3_IFDEF_YES_GBMAP(true, !LOOKGBMAP)',
-    '!RDONLY || !LOOKGBMAP',
     '!RDONLY || !COMPACTMETA',
 ]
 code = '''
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
     lfs3_mount(&lfs3,
             ((RDONLY) ? LFS3_M_RDONLY : LFS3_M_RDWR)
                 | ((FLUSH) ? LFS3_M_FLUSH : 0)
@@ -61,9 +72,6 @@ code = '''
                     : 0)
                 | ((MKCONSISTENT) ? LFS3_M_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_M_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_M_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_M_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_M_CKMETA : 0)
                 | ((CKDATA) ? LFS3_M_CKDATA : 0),
@@ -87,12 +95,12 @@ code = '''
                     ? LFS3_IFDEF_CKDATACKSUMS(LFS3_I_CKDATACKSUMS, -1)
                     : 0)
                 | ((!MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD && !GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | ((!COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
-                | LFS3_IFDEF_YES_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
 
     lfs3_unmount(&lfs3) => 0;
 '''
@@ -109,11 +117,9 @@ defines.CKMETAPARITY = [false, true]
 defines.CKDATACKSUMS = [false, true]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
-defines.GBMAP = [false, true]
 if = [
     'LFS3_IFDEF_YES_REVDBG(REVDBG, LFS3_IFDEF_REVDBG(true, !REVDBG))',
     'LFS3_IFDEF_YES_REVNOISE(REVNOISE, LFS3_IFDEF_REVNOISE(true, !REVNOISE))',
@@ -121,8 +127,6 @@ if = [
     'LFS3_IFDEF_CKFETCHES(true, !CKFETCHES)',
     'LFS3_IFDEF_CKMETAPARITY(true, !CKMETAPARITY)',
     'LFS3_IFDEF_CKDATACKSUMS(true, !CKDATACKSUMS)',
-    'LFS3_IFDEF_YES_GBMAP(true, !LOOKGBMAP)',
-    'LFS3_IFDEF_GBMAP(true, !GBMAP)',
 ]
 code = '''
     lfs3_t lfs3;
@@ -140,9 +144,6 @@ code = '''
                     : 0)
                 | ((MKCONSISTENT) ? LFS3_F_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_F_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_F_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_F_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_F_CKMETA : 0)
                 | ((CKDATA) ? LFS3_F_CKDATA : 0)
@@ -157,13 +158,11 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
-                | LFS3_IFDEF_YES_GBMAP(
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
-                    LFS3_I_GBMAP,
-                    (GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
 
     lfs3_unmount(&lfs3) => 0;
 '''
@@ -171,14 +170,20 @@ code = '''
 
 # test that on-mount traversals do what they say they do
 
-[cases.test_mount_t_relookahead]
+[cases.test_mount_t_lookahead]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 code = '''
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // by default we need a lookahead scan
+    //
+    // unless we have a gbmap, the gbmap is persistent so usually
+    // _doesn't_ need a lookahead scan
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
     struct lfs3_fsinfo fsinfo;
     lfs3_fs_stat(&lfs3, &fsinfo) => 0;
@@ -186,11 +191,11 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
-                | LFS3_IFDEF_YES_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
     lfs3_unmount(&lfs3) => 0;
 
     // with LFS3_M_LOOKAHEAD, mount performs a lookahead scan
@@ -209,12 +214,11 @@ code = '''
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
-                | LFS3_IFDEF_YES_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
     lfs3_unmount(&lfs3) => 0;
 '''
 
-[cases.test_mount_t_regbmap]
+[cases.test_mount_t_lookgbmap]
-ifdef = 'LFS3_GBMAP'
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.SIZE = [
@@ -223,9 +227,14 @@ defines.SIZE = [
     '2*BLOCK_SIZE',
     '8*BLOCK_SIZE',
 ]
+ifdef = 'LFS3_GBMAP'
+if = 'GBMAP'
 code = '''
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR | LFS3_F_GBMAP, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     uint32_t prng = 42;
 
@@ -237,11 +246,10 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
-                | LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
     // write to a file
     lfs3_file_t file;
     lfs3_file_open(&lfs3, &file, "jellyfish",
@@ -262,18 +270,16 @@ code = '''
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
                 | LFS3_I_LOOKAHEAD
-                | LFS3_I_LOOKGBMAP
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
-                | LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
     lfs3_unmount(&lfs3) => 0;
 
-    // with LFS3_M_LOOKGBMAP, mount performs a gbmap repop
+    // with LFS3_M_LOOKAHEAD, mount rebuild the gbmap
     lfs3_mount(&lfs3,
             LFS3_M_RDWR
                 | LFS3_M_LOOKAHEAD
-                | LFS3_M_LOOKGBMAP
                 | ((CKMETA) ? LFS3_M_CKMETA : 0)
                 | ((CKDATA) ? LFS3_M_CKDATA : 0),
             CFG) => 0;
@@ -286,7 +292,7 @@ code = '''
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
-                | LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
     lfs3_unmount(&lfs3) => 0;
 '''
 
@@ -306,7 +312,10 @@ defines.SIZE = [
 defines.GC_COMPACTMETA_THRESH = 'BLOCK_SIZE/2'
 code = '''
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     uint32_t prng = 42;
 
@@ -340,14 +349,13 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || SIZE >= BLOCK_SIZE/4)
-                | LFS3_IFDEF_YES_GBMAP(
+                    ? LFS3_I_LOOKAHEAD
-                    (SIZE >= BLOCK_SIZE/4) ? LFS3_I_LOOKGBMAP : 0,
+                    : 0)
-                    0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
-                | LFS3_IFDEF_YES_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
     lfs3_unmount(&lfs3) => 0;
 
     // with LFS3_M_COMPACTMETA, mount compacts any uncompacted blocks
@@ -363,14 +371,13 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD && (!GBMAP || SIZE >= BLOCK_SIZE/4))
-                | LFS3_IFDEF_YES_GBMAP(
+                    ? LFS3_I_LOOKAHEAD
-                    (SIZE >= BLOCK_SIZE/4) ? LFS3_I_LOOKGBMAP : 0,
+                    : 0)
-                    0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
-                | LFS3_IFDEF_YES_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
 
     // mdir should have been compacted
     lfs3_file_open(&lfs3, &file, "jellyfish", LFS3_O_RDONLY) => 0;
@@ -396,7 +403,10 @@ defines.SIZE = 'FCACHE_SIZE/2'
 defines.ORPHANS = [0, 1, 2, 3, 100]
 code = '''
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     uint32_t prng = 42;
 
@@ -454,14 +464,13 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || ORPHANS >= 100)
-                | LFS3_IFDEF_YES_GBMAP(
+                    ? LFS3_I_LOOKAHEAD
-                    (ORPHANS >= 100) ? LFS3_I_LOOKGBMAP : 0,
+                    : 0)
-                    0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
-                | LFS3_IFDEF_YES_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
     lfs3_unmount(&lfs3) => 0;
 
     // with LFS3_M_MKCONSISTENT, mount cleans up orphans eagerly
@@ -477,15 +486,14 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD && (!GBMAP || ORPHANS >= 100))
-                | LFS3_IFDEF_YES_GBMAP(
+                    ? LFS3_I_LOOKAHEAD
-                    (ORPHANS >= 100) ? LFS3_I_LOOKGBMAP : 0,
+                    : 0)
-                    0)
                 | ((!COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
-                | LFS3_IFDEF_YES_GBMAP(LFS3_I_GBMAP, 0)));
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
 
     // check we can still read the files
     lfs3_file_open(&lfs3, &file, "cuttlefish", LFS3_O_RDONLY) => 0;
@@ -524,7 +532,10 @@ code = '''
         assert(i < 2*BLOCK_COUNT);
 
         lfs3_t lfs3;
-        lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+        lfs3_format(&lfs3,
+                LFS3_F_RDWR
+                    | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+                CFG) => 0;
         lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
 
         // create an interesting filesystem
@@ -613,7 +624,10 @@ code = '''
         assert(i < 2*BLOCK_COUNT);
 
         lfs3_t lfs3;
-        lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+        lfs3_format(&lfs3,
+                LFS3_F_RDWR
+                    | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+                CFG) => 0;
         lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
 
         // create an interesting filesystem
@@ -696,7 +710,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // delete the magic string
     //
@@ -719,7 +736,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // tweak the magic string
     //
@@ -743,7 +763,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // bump the major version
     //
@@ -769,7 +792,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // bump the minor version
     //
@@ -795,7 +821,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set the nonstandard rcompat flag, this will always be incompatible
     // with standard littlefs
@@ -822,7 +851,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set the nonstandard rcompat flag, this will always be incompatible
     // with standard littlefs
@@ -852,7 +884,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set the nonstandard ocompat flag, this will always be incompatible
     // with standard littlefs
@@ -881,7 +916,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set the rdonly flag, this prevents writing from a littlefs image
     //
@@ -910,7 +948,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set the wronly flag, this prevents reading from a littlefs image
     //
@@ -938,7 +979,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set a really far rcompat flag
     //
@@ -969,7 +1013,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     uint8_t flags[9] = {0};
     flags[FLAG / 8] |= 1 << (FLAG % 8);
@@ -1006,7 +1053,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set a really far ocompat flag
     //
@@ -1038,7 +1088,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set a really far rcompat flag
     //
@@ -1069,7 +1122,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     uint8_t flags[9] = {0};
     flags[FLAG / 8] |= 1 << (FLAG % 8);
@@ -1103,7 +1159,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set a really far ocompat flag
     //
@@ -1134,7 +1193,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set an incompatible block size
     //
@@ -1161,7 +1223,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set an incompatible block count
     //
@@ -1188,7 +1253,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set an incompatible block size
     //
@@ -1212,7 +1280,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // set an incompatible file limit
     //
@@ -1249,7 +1320,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create an unknown config
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -1271,7 +1345,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -1359,7 +1436,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -1466,7 +1546,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -1576,7 +1659,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -1686,7 +1772,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -1805,7 +1894,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -1919,7 +2011,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -2029,7 +2124,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // create some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
@@ -2150,7 +2248,10 @@ in = 'lfs3.c'
 code = '''
     // create a superblock
     lfs3_t lfs3;
-    lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
+    lfs3_format(&lfs3,
+            LFS3_F_RDWR
+                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),
+            CFG) => 0;
 
     // with some files
     lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;

tests/test_trvs.toml

@@ -20,11 +20,9 @@ if = '''
 [cases.test_trvs_simple]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
-if = 'GBMAP || !LOOKGBMAP'
 code = '''
     lfs3_t lfs3;
     lfs3_format(&lfs3,
@@ -39,9 +37,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -85,9 +80,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -129,11 +121,9 @@ code = '''
 [cases.test_trvs_idempotent]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
-if = 'GBMAP || !LOOKGBMAP'
 code = '''
     lfs3_t lfs3;
     lfs3_format(&lfs3,
@@ -148,9 +138,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -1777,11 +1764,9 @@ done:;
 [cases.test_trvs_flags]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
-if = 'GBMAP || !LOOKGBMAP'
 code = '''
     lfs3_t lfs3;
     lfs3_format(&lfs3,
@@ -1797,7 +1782,7 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_MKCONSISTENT
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -1809,9 +1794,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -1837,7 +1819,7 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!MKCONSISTENT) ? LFS3_I_MKCONSISTENT : 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD && !GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | ((!COMPACTMETA) ? LFS3_I_COMPACTMETA : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
@@ -1937,7 +1919,7 @@ done:;
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2012,7 +1994,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2045,7 +2027,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2136,7 +2118,7 @@ done:;
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2231,7 +2213,7 @@ done:;
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2334,7 +2316,7 @@ done:;
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2418,9 +2400,8 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || SIZE >= BLOCK_SIZE/4)
-                | ((GBMAP && SIZE >= BLOCK_SIZE/4)
+                    ? LFS3_I_LOOKAHEAD
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
                     : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
@@ -2518,17 +2499,18 @@ code = '''
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 // ok we might've updated lookahead if write stayed in
                 // cache
-                | ((!LOOKAHEAD || SIZE > FCACHE_SIZE || SYNC)
+                | (((!LOOKAHEAD || SIZE > FCACHE_SIZE || SYNC)
-                    ? LFS3_I_LOOKAHEAD : 0)
+                        && (!GBMAP || SIZE >= BLOCK_SIZE/4))
-                | ((GBMAP && SIZE >= BLOCK_SIZE/4)
+                    ? LFS3_I_LOOKAHEAD
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
                     : 0)
                 | LFS3_I_COMPACTMETA
                 // and maybe ckmeta/ckdata, note ckdata implies ckmeta
                 | (((!CKMETA && !CKDATA) || SIZE > FCACHE_SIZE || SYNC)
-                    ? LFS3_I_CKMETA : 0)
+                    ? LFS3_I_CKMETA
+                    : 0)
                 | ((!CKDATA || SIZE > FCACHE_SIZE || SYNC)
-                    ? LFS3_I_CKDATA : 0)
+                    ? LFS3_I_CKDATA
+                    : 0)
                 | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_GBMAP, -1) : 0)));
 
     // check the file contents
@@ -2640,7 +2622,7 @@ done:;
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2773,7 +2755,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -2896,7 +2877,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -3003,7 +2983,7 @@ done:;
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -3138,7 +3118,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -3263,7 +3242,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -3383,7 +3361,7 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((DESYNC) ? LFS3_I_MKCONSISTENT : 0)
-                | ((!(LOOKAHEAD && DESYNC)) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!(LOOKAHEAD && DESYNC) && !GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | ((!(CKMETA && DESYNC) && !(CKDATA && DESYNC))
@@ -3529,7 +3507,6 @@ done:;
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((DESYNC) ? LFS3_I_MKCONSISTENT : 0)
                 | ((!(LOOKAHEAD && DESYNC)) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | ((!(CKMETA && DESYNC) && !(CKDATA && DESYNC))
@@ -3665,7 +3642,6 @@ done:;
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((DESYNC) ? LFS3_I_MKCONSISTENT : 0)
                 | ((!(LOOKAHEAD && DESYNC)) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | ((!(CKMETA && DESYNC) && !(CKDATA && DESYNC))
@@ -3787,7 +3763,6 @@ done:;
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((DESYNC) ? LFS3_I_MKCONSISTENT : 0)
                 | ((!(LOOKAHEAD && DESYNC)) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | ((!(CKMETA && DESYNC) && !(CKDATA && DESYNC))
@@ -3911,7 +3886,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4037,7 +4011,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4166,7 +4139,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4308,7 +4280,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4450,7 +4421,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4572,7 +4542,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4695,7 +4664,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4831,7 +4799,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -4968,7 +4935,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -5159,7 +5125,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -5366,7 +5331,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -5568,7 +5532,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -5767,7 +5730,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -5972,7 +5934,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6182,7 +6143,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6397,7 +6357,6 @@ done:;
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6470,7 +6429,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6508,7 +6467,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6533,7 +6492,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD && !GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
@@ -6620,7 +6579,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6667,7 +6625,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6695,7 +6652,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
@@ -6763,7 +6719,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6804,7 +6760,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6830,7 +6785,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
@@ -6925,7 +6879,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -6978,7 +6932,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -7005,7 +6958,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
@@ -7155,7 +7107,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -7215,7 +7166,6 @@ code = '''
                 LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                     | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                     | LFS3_I_LOOKAHEAD
-                    | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                     | LFS3_I_COMPACTMETA
                     | LFS3_I_CKMETA
                     | LFS3_I_CKDATA
@@ -7244,7 +7194,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
@@ -7399,7 +7348,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -7464,7 +7412,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -7493,7 +7440,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
                 | ((!CKDATA) ? LFS3_I_CKDATA : 0)
@@ -7613,10 +7559,7 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS > 0) ? LFS3_I_MKCONSISTENT : 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || ORPHANS >= 100) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP && ORPHANS >= 100)
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
-                    : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -7683,9 +7626,9 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | ((!LOOKAHEAD || ORPHANS > 0) ? LFS3_I_LOOKAHEAD : 0)
+                | (((!LOOKAHEAD || ORPHANS > 0)
-                | ((GBMAP && ORPHANS >= 100)
+                        && (!GBMAP || ORPHANS >= 100))
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
+                    ? LFS3_I_LOOKAHEAD
                     : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
@@ -7765,7 +7708,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -7854,9 +7797,9 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS >= 3) ? LFS3_I_MKCONSISTENT : 0)
-                | ((!LOOKAHEAD || ORPHANS > 0) ? LFS3_I_LOOKAHEAD : 0)
+                | (((!LOOKAHEAD || ORPHANS > 0)
-                | ((GBMAP && ORPHANS >= 100)
+                        && (!GBMAP || ORPHANS >= 100))
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
+                    ? LFS3_I_LOOKAHEAD
                     : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
@@ -7963,7 +7906,6 @@ code = '''
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS > 0) ? LFS3_I_MKCONSISTENT : 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -8044,7 +7986,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD || ORPHANS > 0) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | (((!CKMETA && !CKDATA) || ORPHANS > 0) ? LFS3_I_CKMETA : 0)
@@ -8150,7 +8091,6 @@ code = '''
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS > 0) ? LFS3_I_MKCONSISTENT : 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -8231,7 +8171,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD || ORPHANS > 0) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | (((!CKMETA && !CKDATA) || ORPHANS > 0) ? LFS3_I_CKMETA : 0)
@@ -8338,7 +8277,6 @@ code = '''
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS > 0) ? LFS3_I_MKCONSISTENT : 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -8427,7 +8365,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD || ORPHANS > 0) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | (((!CKMETA && !CKDATA) || ORPHANS > 0) ? LFS3_I_CKMETA : 0)
@@ -8534,7 +8471,6 @@ code = '''
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS > 0) ? LFS3_I_MKCONSISTENT : 0)
                 | LFS3_I_LOOKAHEAD
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -8623,7 +8559,6 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((!LOOKAHEAD || ORPHANS > 0) ? LFS3_I_LOOKAHEAD : 0)
-                | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1) : 0)
                 | LFS3_I_COMPACTMETA
                 // note ckdata implies ckmeta
                 | (((!CKMETA && !CKDATA) || ORPHANS > 0) ? LFS3_I_CKMETA : 0)
@@ -8747,9 +8682,8 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS > 0) ? LFS3_I_MKCONSISTENT : 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || ORPHANS >= 100)
-                | ((GBMAP && ORPHANS >= 100)
+                    ? LFS3_I_LOOKAHEAD
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
                     : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
@@ -8822,9 +8756,8 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || ORPHANS >= 100)
-                | ((GBMAP && ORPHANS >= 100)
+                    ? LFS3_I_LOOKAHEAD
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
                     : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
@@ -8851,9 +8784,8 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | ((!LOOKAHEAD) ? LFS3_I_LOOKAHEAD : 0)
+                | ((!LOOKAHEAD && (!GBMAP || ORPHANS >= 100))
-                | ((GBMAP && ORPHANS >= 100)
+                    ? LFS3_I_LOOKAHEAD
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
                     : 0)
                 // note ckdata implies ckmeta
                 | ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
@@ -8955,7 +8887,7 @@ code = '''
     assert(fsinfo.flags == (
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP) ? LFS3_I_LOOKAHEAD : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
                 | LFS3_I_CKDATA
@@ -9049,9 +8981,8 @@ code = '''
             LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
                 | LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
                 | ((ORPHANS >= 3) ? LFS3_I_MKCONSISTENT : 0)
-                | LFS3_I_LOOKAHEAD
+                | ((!GBMAP || ORPHANS >= 100)
-                | ((GBMAP && ORPHANS >= 100)
+                    ? LFS3_I_LOOKAHEAD
-                    ? LFS3_IFDEF_GBMAP(LFS3_I_LOOKGBMAP, -1)
                     : 0)
                 | LFS3_I_COMPACTMETA
                 | LFS3_I_CKMETA
@@ -9100,14 +9031,12 @@ code = '''
 defines.STEPS = [1, 2, 4, 8, 16, 32, 64, 128]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [true]
 defines.CKDATA = [true]
 # set compactmeta thresh to minimum
 defines.GC_COMPACTMETA_THRESH = 'BLOCK_SIZE/2'
 defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256]
-if = 'GBMAP || !LOOKGBMAP'
 code = '''
     // test creating directories
     lfs3_t lfs3;
@@ -9123,9 +9052,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -9219,7 +9145,6 @@ code = '''
 defines.STEPS = [1, 2, 4, 8, 16, 32, 64, 128]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [true]
 defines.CKDATA = [true]
@@ -9229,7 +9154,6 @@ defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256]
 defines.OPS = '2*N'
 defines.SEED = 42
 fuzz = 'SEED'
-if = 'GBMAP || !LOOKGBMAP'
 code = '''
     // test fuzz with dirs
     lfs3_t lfs3;
@@ -9249,9 +9173,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -9409,7 +9330,6 @@ code = '''
 defines.STEPS = [1, 2, 4, 8, 16, 32, 64, 128]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [true]
 defines.CKDATA = [true]
@@ -9425,10 +9345,7 @@ defines.SIZE = [
     '2*BLOCK_SIZE',
     '4*BLOCK_SIZE',
 ]
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 32'
-    '(SIZE*N)/BLOCK_SIZE <= 32',
-    'GBMAP || !LOOKGBMAP',
-]
 code = '''
     // test creating files
     lfs3_t lfs3;
@@ -9444,9 +9361,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -9524,7 +9438,6 @@ code = '''
 defines.STEPS = [1, 2, 4, 8, 16, 32, 64, 128]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [true]
 defines.CKDATA = [true]
@@ -9543,10 +9456,7 @@ defines.SIZE = [
 ]
 defines.SEED = 42
 fuzz = 'SEED'
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 16'
-    '(SIZE*N)/BLOCK_SIZE <= 16',
-    'GBMAP || !LOOKGBMAP',
-]
 code = '''
     // test fuzz with files
     lfs3_t lfs3;
@@ -9567,9 +9477,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -9778,7 +9685,6 @@ code = '''
 defines.STEPS = [1, 2, 4, 8, 16, 32, 64, 128]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [true]
 defines.CKDATA = [true]
@@ -9806,7 +9712,6 @@ if = [
     'CHUNK <= SIZE',
     # this just saves testing time
     'SIZE <= 4*1024*FRAGMENT_SIZE',
-    'GBMAP || !LOOKGBMAP',
 ]
 code = '''
     // test with complex file writes
@@ -9851,9 +9756,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -9950,7 +9852,6 @@ code = '''
 defines.STEPS = [1, 2, 4, 8, 16, 32, 64, 128]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [true]
 defines.CKDATA = [true]
@@ -9971,10 +9872,7 @@ defines.SIZE = [
 ]
 defines.SEED = 42
 fuzz = 'SEED'
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 16'
-    '(SIZE*N)/BLOCK_SIZE <= 16',
-    'GBMAP || !LOOKGBMAP',
-]
 code = '''
     // test with uncreats, zombies, etc
     lfs3_t lfs3;
@@ -10006,9 +9904,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;
@@ -10415,7 +10310,6 @@ code = '''
 defines.STEPS = [1, 2, 4, 8, 16, 32, 64, 128]
 defines.MKCONSISTENT = [false, true]
 defines.LOOKAHEAD = [false, true]
-defines.LOOKGBMAP = [false, true]
 defines.COMPACTMETA = [false, true]
 defines.CKMETA = [true]
 defines.CKDATA = [true]
@@ -10436,10 +10330,7 @@ defines.SIZE = [
 ]
 defines.SEED = 42
 fuzz = 'SEED'
-if = [
+if = '(SIZE*N)/BLOCK_SIZE <= 16'
-    '(SIZE*N)/BLOCK_SIZE <= 16',
-    'GBMAP || !LOOKGBMAP',
-]
 code = '''
     // test with uncreats, zombies, dirs, etc
     lfs3_t lfs3;
@@ -10472,9 +10363,6 @@ code = '''
             LFS3_T_RDWR
                 | ((MKCONSISTENT) ? LFS3_T_MKCONSISTENT : 0)
                 | ((LOOKAHEAD) ? LFS3_T_LOOKAHEAD : 0)
-                | ((LOOKGBMAP)
-                    ? LFS3_IFDEF_GBMAP(LFS3_T_LOOKGBMAP, -1)
-                    : 0)
                 | ((COMPACTMETA) ? LFS3_T_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_T_CKMETA : 0)
                 | ((CKDATA) ? LFS3_T_CKDATA : 0)) => 0;