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rdonly: Dropped LFS3_TSTATE_OMDIRS/OBTREE when LFS3_RDONLY

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If we can't write to the filesystem, we can't out out-of-sync files, so
there's no need to traverse open file handles at all.

Saves a bit of code in LFS3_RDONLY mode:

                  code          stack          ctx
  rdonly before: 10776            840          524
  rdonly after:  10664 (-1.0%)    840 (+0.0%)  524 (+0.0%)

In theory we could also skip this check when mounted LFS3_M_RDONLY, but
checking for that flag would add code and we don't really care about
CPU-related performance here.

No code changes in default mode.
This commit is contained in:
Christopher Haster
2025-06-05 15:34:30 -05:00
parent 88eb1714b1
commit e31a90d8f3
1 changed files with 12 additions and 4 deletions
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lfs3.c
+12 -4
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@@ -9458,7 +9458,6 @@ enum {
LFS3_TSTATE_MDIRS = 3,
LFS3_TSTATE_MDIR = 4,
LFS3_TSTATE_BTREE = 5,
// TODO can we skip open-things when LFS3_RDONLY?
LFS3_TSTATE_OMDIRS = 6,
LFS3_TSTATE_OBTREE = 7,
LFS3_TSTATE_DONE = 8,
@@ -9673,12 +9672,16 @@ static int lfs3_mtree_traverse_(lfs3_t *lfs3, lfs3_traversal_t *t,
// scan for blocks/btrees in our opened file list
case LFS3_TSTATE_OMDIRS:;
// reached end of opened files? return to mdir traversal
if (!t->ot) {
if (LFS3_IFDEF_RDONLY(
// we don't need to traverse these if rdonly
true,
!t->ot)) {
t->b.o.mdir.mid += 1;
lfs3_t_settstate(&t->b.o.flags, LFS3_TSTATE_MDIR);
continue;
}
#ifndef LFS3_RDONLY
// skip unrelated files, we only care about unsync reg files
// associated with the current mid
//
@@ -9708,6 +9711,7 @@ static int lfs3_mtree_traverse_(lfs3_t *lfs3, lfs3_traversal_t *t,
*bptr = file->leaf.bptr;
return 0;
}
#endif
continue;
@@ -9740,11 +9744,15 @@ static int lfs3_mtree_traverse_(lfs3_t *lfs3, lfs3_traversal_t *t,
lfs3_t_settstate(&t->b.o.flags, LFS3_TSTATE_OMDIRS);
continue;
// end of opened btree? go to next opened file
} else if (lfs3_t_tstate(t->b.o.flags)
== LFS3_TSTATE_OBTREE) {
} else if (LFS3_IFDEF_RDONLY(
false,
lfs3_t_tstate(t->b.o.flags)
== LFS3_TSTATE_OBTREE)) {
#ifndef LFS3_RDONLY
t->ot = t->ot->next;
lfs3_t_settstate(&t->b.o.flags, LFS3_TSTATE_OMDIRS);
continue;
#endif
} else {
LFS3_UNREACHABLE();
}