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Extended lfsr_mount to accept mount flags

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This has been a long-time coming, mount flags are just too useful for
configuring a filesystem at runtime.

Currently this is limited to LFS_M_RDONLY and LFS_M_CKPROGS, but there
are a few more planned in the future:

  LFS_M_RDWR     = 0x0000, // Mount the filesystem as read and write
  LFS_M_RDONLY   = 0x0001, // Mount the filesystem as readonly
  LFS_M_STRICT*  = 0x0002, // Error if on-disk config does not match
  LFS_M_FORCE*   = 0x0004, // Ignore compat flags, mount readonly
  LFS_M_FORCEWITHRECKLESSABANDON*
                 = 0x0008, // Ignore compat flags, mount read write

  LFS_M_CKPROGS  = 0x0010, // Check progs by reading back progged data
  LFS_M_CKREADS* = 0x0020, // Check reads via checksums

  * Hypothetical

As a convenience, we also return mount flags in the struct lfs_fsinfo's
flags field as their relevant LFS_I_* variants. Though only to match
statvfs, and only because it's cheap, littlefs's API is low-level and we
should expect users to know what flags they passed to lfsr_mount.

As for the new mount flags:

- LFS_M_RDONLY - For consistency with existing APIs, this just asserts
  on write operations, which makes it a bit useless... But the info flag
  LFS_I_RDONLY may be useful for falling back to a readonly mode if
  we encounter on-disk compat issues.

  At least if implement the theoretical LFS_UNTRUSTED_USER mode
  LFS_M_RDONLY could become a runtime error.

- LFS_M_RDWR - This really just exists to compliment LFS_M_RDONLY and to
  match LFS_O_RDONLY/LFS_O_RDWR. It's just an alias for 0, and I don't
  think there will ever be a reason to make it non-0 (but I can always
  be wrong!).

- LFS_M_CKPROGS - This replaces the check_progs config option and avoids
  using a full byte to store a bool.

  We should probably also have a compile-time option to compile this out
  (LFS_NO_CKPROGS?), but that's a future thing to do.

This ended up adding a surprising bit of code, considering we're just
moving flags around, and noise in lfs_alloc added a bit of stack again:

           code          stack
  before: 35880           2672
  after:  35932 (+0.1%)   2680 (+0.3%)
This commit is contained in:
Christopher Haster
2024-07-15 01:48:37 -05:00
parent 0a3cb2dd3a
commit acfae9e072
25 changed files with 1322 additions and 1126 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_relocations.toml
+16 -16
View File
@@ -18,7 +18,7 @@ defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
code = '''
lfs_t lfs;
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
// make this many directories
for (lfs_size_t i = 0; i < N; i++) {
@@ -32,7 +32,7 @@ code = '''
// remount?
if (remount) {
lfsr_unmount(&lfs) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// grm should be zero here
@@ -100,7 +100,7 @@ fuzz = 'SEED'
code = '''
lfs_t lfs;
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
// set up a simulation to compare against
lfs_size_t *sim = malloc(N*sizeof(lfs_size_t));
@@ -194,7 +194,7 @@ code = '''
// remount?
if (remount) {
lfsr_unmount(&lfs) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// grm should be zero here
@@ -258,7 +258,7 @@ if = '(SIZE*N)/BLOCK_SIZE <= 32'
code = '''
lfs_t lfs;
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
// create this many files
uint32_t prng = 42;
@@ -282,7 +282,7 @@ code = '''
// remount?
if (remount) {
lfsr_unmount(&lfs) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// check that our writes worked
@@ -334,7 +334,7 @@ if = '(SIZE*N)/BLOCK_SIZE <= 16'
code = '''
lfs_t lfs;
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
// set up a simulation to compare against
lfs_size_t *sim = malloc(N*sizeof(lfs_size_t));
@@ -465,7 +465,7 @@ code = '''
// remount?
if (remount) {
lfsr_unmount(&lfs) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// check that our files match our simulation
@@ -547,7 +547,7 @@ if = '(SIZE*N)/BLOCK_SIZE <= 16'
code = '''
lfs_t lfs;
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
// set up a simulation to compare against
lfs_size_t *sim = malloc(N*sizeof(lfs_size_t));
@@ -887,7 +887,7 @@ if = '(SIZE*N)/BLOCK_SIZE <= 16'
code = '''
lfs_t lfs;
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
// set up a simulation to compare against
lfs_size_t *sim = malloc(N*sizeof(lfs_size_t));
@@ -1316,10 +1316,10 @@ reentrant = true
code = '''
// format once per test
lfs_t lfs;
int err = lfsr_mount(&lfs, CFG);
int err = lfsr_mount(&lfs, LFS_M_RDWR, CFG);
if (err) {
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// keep some test state on disk to survive powerloss
@@ -1455,7 +1455,7 @@ code = '''
// remount?
if (remount) {
lfsr_unmount(&lfs) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// check that things look more-or-less ok
@@ -1537,10 +1537,10 @@ reentrant = true
code = '''
// format once per test
lfs_t lfs;
int err = lfsr_mount(&lfs, CFG);
int err = lfsr_mount(&lfs, LFS_M_RDWR, CFG);
if (err) {
lfsr_format(&lfs, CFG) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// keep some test state on disk to survive powerloss
@@ -1790,7 +1790,7 @@ code = '''
// remount?
if (remount) {
lfsr_unmount(&lfs) => 0;
lfsr_mount(&lfs, CFG) => 0;
lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
}
// check that things look more-or-less ok