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Dropped the HASORPHAN scan in lfsr_mount

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The motivation here is to simplify lfsr_mount, but there's a number of
knock-on effects.

For one, lfsr_mount should now be faster on filesystems with large
blocks:

  O(nb(log b)(log_b n)) -> O(nb(log_b n))

But we now no longer check if our filesystem contains orphaned
stickynotes or unknown filetypes:

- Orphaned stickynotes turned out to not be a big deal. If we find
  orphans we'd need to do a second traversal to remove them anyways (no
  mutation allowed in lfsr_mount), so this actually ends up a net
  improvement in the found-orphan case.

  If anything, doing a traversal on first write sets user expectations
  correctly, and can be offloaded with lfsr_fs_mkconsistent or
  lfsr_fs_gc.

- Unknown filetypes are a bit more annoying (I actually forgot about
  this check), but unknown filetypes that require special care should
  probably set WCOMPAT/RCOMPAT flags.

  Allowing unknown filetypes is a bit more flexible in cases where a
  filesystem image is being shared between drivers with different
  features (bootloader + app for example).

  Though we should probably add more checks/tests that we're handling
  these correctly now that we no longer just bail during mount...

Also renamed LFS_I_HASORPHANS -> LFS_I_UNTIDY.

Not doing something is cheaper than doing something, so this saves a bit
of code:

           code          stack          ctx
  before: 38120           2624          752
  after:  38020 (-0.3%)   2624 (+0.0%)  752 (+0.0%)
This commit is contained in:
Christopher Haster
2024-12-30 20:26:06 -06:00
parent 5302213ec9
commit 6e63920338
5 changed files with 45 additions and 122 deletions
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tests/test_traversal.toml
+12 -10
View File
@@ -1680,7 +1680,8 @@ code = '''
struct lfs_fsinfo fsinfo;
lfsr_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS_I_CANLOOKAHEAD
LFS_I_INCONSISTENT
| LFS_I_CANLOOKAHEAD
| LFS_I_UNCOMPACTED));
// try traversing
@@ -1704,7 +1705,8 @@ code = '''
// check flags after
lfsr_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.flags == (
((!LOOKAHEAD) ? LFS_I_CANLOOKAHEAD : 0)
((!MKCONSISTENT) ? LFS_I_INCONSISTENT : 0)
| ((!LOOKAHEAD) ? LFS_I_CANLOOKAHEAD : 0)
| ((!COMPACT) ? LFS_I_UNCOMPACTED : 0)));
lfsr_unmount(&lfs) => 0;
@@ -6327,7 +6329,7 @@ code = '''
// we should have cleaned up all grms/orphans
assert(lfs.grm.mids[0] == -1);
assert(lfs.grm.mids[1] == -1);
assert(!(lfs.flags & LFS_I_HASORPHANS));
assert(!(lfs.flags & LFS_I_UNTIDY));
// which means there shouldn't be that many files left
assert((lfs.mtree.u.weight & 0x7fffffff) <= (2 << lfs.mdir_bits));
@@ -6466,7 +6468,7 @@ code = '''
assert(lfs.grm.mids[1] == -1);
// if we introduce actual orphans, me _must not_ clear the orphan flag
if (ORPHANS >= 3) {
assert(lfs.flags & LFS_I_HASORPHANS);
assert(lfs.flags & LFS_I_UNTIDY);
}
// if we introduced actual orphans, we _must_ be marked as inconsistent
@@ -6618,7 +6620,7 @@ code = '''
// we should have cleaned up all grms/orphans
assert(lfs.grm.mids[0] == -1);
assert(lfs.grm.mids[1] == -1);
assert(!(lfs.flags & LFS_I_HASORPHANS));
assert(!(lfs.flags & LFS_I_UNTIDY));
// which means there shouldn't be that many files left
assert((lfs.mtree.u.weight & 0x7fffffff) <= (2 << lfs.mdir_bits));
@@ -6771,7 +6773,7 @@ code = '''
// we should have cleaned up all grms/orphans
assert(lfs.grm.mids[0] == -1);
assert(lfs.grm.mids[1] == -1);
assert(!(lfs.flags & LFS_I_HASORPHANS));
assert(!(lfs.flags & LFS_I_UNTIDY));
// which means there shouldn't be that many files left
assert((lfs.mtree.u.weight & 0x7fffffff) <= (2 << lfs.mdir_bits));
@@ -6935,7 +6937,7 @@ code = '''
// we should have cleaned up all grms/orphans
assert(lfs.grm.mids[0] == -1);
assert(lfs.grm.mids[1] == -1);
assert(!(lfs.flags & LFS_I_HASORPHANS));
assert(!(lfs.flags & LFS_I_UNTIDY));
// which means there shouldn't be that many files left
assert((lfs.mtree.u.weight & 0x7fffffff) <= (2 << lfs.mdir_bits));
@@ -7097,7 +7099,7 @@ code = '''
// we should have cleaned up all grms/orphans
assert(lfs.grm.mids[0] == -1);
assert(lfs.grm.mids[1] == -1);
assert(!(lfs.flags & LFS_I_HASORPHANS));
assert(!(lfs.flags & LFS_I_UNTIDY));
// which means there shouldn't be that many files left
assert((lfs.mtree.u.weight & 0x7fffffff) <= (2 << lfs.mdir_bits));
@@ -7257,7 +7259,7 @@ code = '''
// we should have cleaned up all grms/orphans
assert(lfs.grm.mids[0] == -1);
assert(lfs.grm.mids[1] == -1);
assert(!(lfs.flags & LFS_I_HASORPHANS));
assert(!(lfs.flags & LFS_I_UNTIDY));
// which means there shouldn't be that many files left
assert((lfs.mtree.u.weight & 0x7fffffff) <= (2 << lfs.mdir_bits));
@@ -7445,7 +7447,7 @@ code = '''
assert(lfs.grm.mids[1] == -1);
// if we introduce actual orphans, me _must not_ clear the orphan flag
if (ORPHANS >= 3) {
assert(lfs.flags & LFS_I_HASORPHANS);
assert(lfs.flags & LFS_I_UNTIDY);
}
// mdirs should have been compacted