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Rearranged on-disk compat flags

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Other than moving things around to make space for planned features, this
also adopts the idea of allowing compat flags to be ored into a single
32-bit integer, at least in the short-term.

Note though that these are still stored in separate wcompat/rcompat
tags, to make compat tests easier, and we may introduce conflicting
flags in the future if we run out of 32-bits. This is just an indulgence
to potentially make tooling/debugging easier until that happens.

Rcompat flags:

  RCOMPAT_NONSTANDARD+
                     0x00000001  ---- ---- ---- ---- ---- ---- ---- ---1
  RCOMPAT_WRONLY+    0x00000004  ---- ---- ---- ---- ---- ---- ---- -1--
  RCOMPAT_MMOSS      0x00000010  ---- ---- ---- ---- ---- ---- ---1 ----
  RCOMPAT_MSPROUT+   0x00000020  ---- ---- ---- ---- ---- ---- --1- ----
  RCOMPAT_MSHRUB+    0x00000040  ---- ---- ---- ---- ---- ---- -1-- ----
  RCOMPAT_MTREE      0x00000080  ---- ---- ---- ---- ---- ---- 1--- ----
  RCOMPAT_BMOSS+     0x00000100  ---- ---- ---- ---- ---- ---1 ---- ----
  RCOMPAT_BSPROUT+   0x00000200  ---- ---- ---- ---- ---- --1- ---- ----
  RCOMPAT_BSHRUB     0x00000400  ---- ---- ---- ---- ---- -1-- ---- ----
  RCOMPAT_BTREE      0x00000800  ---- ---- ---- ---- ---- 1--- ---- ----
  RCOMPAT_MDIRR1*    0x00001000  ---- ---- ---- ---- ---1 ---- ---- ----
  RCOMPAT_MDIRR2*    0x00002000  ---- ---- ---- ---- --1- ---- ---- ----
  RCOMPAT_MDIRR3*    0x00003000  ---- ---- ---- ---- --11 ---- ---- ----
  RCOMPAT_BTREER1*   0x00004000  ---- ---- ---- ---- -1-- ---- ---- ----
  RCOMPAT_BTREER2*   0x00008000  ---- ---- ---- ---- 1--- ---- ---- ----
  RCOMPAT_BTREER3*   0x0000c000  ---- ---- ---- ---- 11-- ---- ---- ----
  RCOMPAT_GRM        0x00010000  ---- ---- ---- ---1 ---- ---- ---- ----
  RCOMPAT_GMV?       0x00020000  ---- ---- ---- --1- ---- ---- ---- ----
  RCOMPAT_GDDTREE*   0x00100000  ---- ---- ---1 ---- ---- ---- ---- ----
  RCOMPAT_GPTREE*    0x00200000  ---- ---- --1- ---- ---- ---- ---- ----
  RCOMPAT_DATAR1*    0x00400000  ---- ---- -1-- ---- ---- ---- ---- ----
  RCOMPAT_DATAR2*    0x00800000  ---- ---- 1--- ---- ---- ---- ---- ----
  RCOMPAT_DATAR3*    0x00c00000  ---- ---- 11-- ---- ---- ---- ---- ----
  rcompat_OVERFLOW+  0x80000000  1--- ---- ---- ---- ---- ---- ---- ----

  * Planned
  + Reserved
  ? Hypothetical

Wcompat flags:

  WCOMPAT_NONSTANDARD+
                     0x00000001  ---- ---- ---- ---- ---- ---- ---- ---1
  WCOMPAT_RDONLY+    0x00000002  ---- ---- ---- ---- ---- ---- ---- --1-
  WCOMPAT_GCKSUM     0x00040000  ---- ---- ---- -1-- ---- ---- ---- ----
  WCOMPAT_GBMAP      0x00080000  ---- ---- ---- 1--- ---- ---- ---- ----
  WCOMPAT_DIR        0x01000000  ---- ---1 ---- ---- ---- ---- ---- ----
  WCOMPAT_SYMLINK?   0x02000000  ---- --1- ---- ---- ---- ---- ---- ----
  WCOMPAT_SNAPSHOT?  0x04000000  ---- -1-- ---- ---- ---- ---- ---- ----
  wcompat_OVERFLOW+  0x80000000  1--- ---- ---- ---- ---- ---- ---- ----

  + Reserved
  ? Hypothetical

Ocompat flags:

  OCOMPAT_NONSTANDARD+
                     0x00000001  ---- ---- ---- ---- ---- ---- ---- ---1
  ocompat_OVERFLOW+  0x80000000  1--- ---- ---- ---- ---- ---- ---- ----

  + Reserved

Other notes:

- M* and B* struct flags were reordered to match META -> DATA order
  elsewhere. This no longer matches the tag ordering, but there's an
  argument the B* tags apply more generally (all btrees) than the B*
  compat flag (only file btrees).

- MDIR/BTREE/DATA redund flags were moved near relevant flags, rather
  than sticking them in the higher-order bits as we are planning to do
  in the M_*/F_* flags. The compat flags already won't match because of
  the mdir/btree split (which is IMO too much detail to include in
  M_*/F_* flags, but hard to argue against in the compat flags), and
  this keeps the highest bit free for OVERFLOW, which is useful
  internally.

- Moving DIR to the current-highest bit makes it easy to add 6 more file
  types (7 if you ignore OVERFLOW), before things start getting cramped.

No code changes.
This commit is contained in:
Christopher Haster
2025-11-13 15:46:15 -06:00
parent 8233ac9dfe
commit 2d68db965b
5 changed files with 72 additions and 71 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lfs3.c
+19 -19
View File
@@ -15267,24 +15267,24 @@ static int lfs3_deinit(lfs3_t *lfs3) {
// note, "understanding" does not necessarily mean support
//
#define LFS3_RCOMPAT_NONSTANDARD 0x00000001 // Non-standard filesystem format
#define LFS3_RCOMPAT_WRONLY 0x00000002 // Reading is disallowed
#define LFS3_RCOMPAT_BMOSS 0x00000010 // Files may use inlined data
#define LFS3_RCOMPAT_BSPROUT 0x00000020 // Files may use block pointers
#define LFS3_RCOMPAT_BSHRUB 0x00000040 // Files may use inlined btrees
#define LFS3_RCOMPAT_BTREE 0x00000080 // Files may use btrees
#define LFS3_RCOMPAT_MMOSS 0x00000100 // May use an inlined mdir
#define LFS3_RCOMPAT_MSPROUT 0x00000200 // May use an mdir pointer
#define LFS3_RCOMPAT_MSHRUB 0x00000400 // May use an inlined mtree
#define LFS3_RCOMPAT_MTREE 0x00000800 // May use an mtree
#define LFS3_RCOMPAT_GRM 0x00001000 // Global-remove in use
#define LFS3_RCOMPAT_WRONLY 0x00000004 // Reading is disallowed
#define LFS3_RCOMPAT_MMOSS 0x00000010 // May use an inlined mdir
#define LFS3_RCOMPAT_MSPROUT 0x00000020 // May use an mdir pointer
#define LFS3_RCOMPAT_MSHRUB 0x00000040 // May use an inlined mtree
#define LFS3_RCOMPAT_MTREE 0x00000080 // May use an mtree
#define LFS3_RCOMPAT_BMOSS 0x00000100 // Files may use inlined data
#define LFS3_RCOMPAT_BSPROUT 0x00000200 // Files may use block pointers
#define LFS3_RCOMPAT_BSHRUB 0x00000400 // Files may use inlined btrees
#define LFS3_RCOMPAT_BTREE 0x00000800 // Files may use btrees
#define LFS3_RCOMPAT_GRM 0x00010000 // Global-remove in use
// internal
#define LFS3_rcompat_OVERFLOW 0x80000000 // Can't represent all flags
#define LFS3_WCOMPAT_NONSTANDARD 0x00000001 // Non-standard filesystem format
#define LFS3_WCOMPAT_RDONLY 0x00000002 // Writing is disallowed
#define LFS3_WCOMPAT_DIR 0x00000010 // Directory files in use
#define LFS3_WCOMPAT_GCKSUM 0x00001000 // Global-checksum in use
#define LFS3_WCOMPAT_GBMAP 0x00002000 // Global on-disk block-map in use
#define LFS3_WCOMPAT_GCKSUM 0x00040000 // Global-checksum in use
#define LFS3_WCOMPAT_GBMAP 0x00080000 // Global on-disk block-map in use
#define LFS3_WCOMPAT_DIR 0x01000000 // Directory files in use
// internal
#define LFS3_wcompat_OVERFLOW 0x80000000 // Can't represent all flags
@@ -15303,20 +15303,20 @@ static inline bool lfs3_wcompat_isgbmap(lfs3_wcompat_t flags) {
// figure out what compat flags the current fs configuration needs
static inline lfs3_rcompat_t lfs3_rcompat(const lfs3_t *lfs3) {
(void)lfs3;
return LFS3_RCOMPAT_BSHRUB
| LFS3_RCOMPAT_BTREE
| LFS3_RCOMPAT_MMOSS
return LFS3_RCOMPAT_MMOSS
| LFS3_RCOMPAT_MTREE
| LFS3_RCOMPAT_BSHRUB
| LFS3_RCOMPAT_BTREE
| LFS3_RCOMPAT_GRM;
}
static inline lfs3_wcompat_t lfs3_wcompat(const lfs3_t *lfs3) {
(void)lfs3;
return LFS3_WCOMPAT_DIR
| LFS3_WCOMPAT_GCKSUM
return LFS3_WCOMPAT_GCKSUM
| LFS3_IFDEF_GBMAP(
(lfs3_f_isgbmap(lfs3->flags)) ? LFS3_WCOMPAT_GBMAP : 0,
0);
0)
| LFS3_WCOMPAT_DIR;
}
static inline lfs3_ocompat_t lfs3_ocompat(const lfs3_t *lfs3) {