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Added ability to bump on-disk minor version

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This just means a rewrite of the superblock entry with the new minor
version.

Though it's interesting to note, we don't need to rewrite the superblock
entry until the first write operation in the filesystem, an optimization
that is already in use for the fixing of orphans and in-flight moves.

To keep track of any outdated minor version found during lfs_mount, we
can carve out a bit from the reserved bits in our gstate. These are
currently used for a counter tracking the number of orphans in the
filesystem, but this is usually a very small number so this hopefully
won't be an issue.

In-device gstate tag:

  [--       32      --]
  [1|- 11 -| 10 |1| 9 ]
   ^----^-----^--^--^-- 1-bit has orphans
        '-----|--|--|-- 11-bit move type
              '--|--|-- 10-bit move id
                 '--|-- 1-bit needs superblock
                    '-- 9-bit orphan count
This commit is contained in:
Christopher Haster
2023-04-20 16:42:19 -05:00
parent ca0da3d490
commit 4c9360020e
2 changed files with 160 additions and 5 deletions
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82
tests/test_compat.toml
View File

@@ -1276,3 +1276,85 @@ code = '''
// mount should now fail
lfs_mount(&lfs, cfg) => LFS_ERR_INVAL;
'''
# test that we correctly bump the minor version
[cases.test_compat_minor_bump]
in = 'lfs.c'
if = 'LFS_DISK_VERSION_MINOR > 0'
code = '''
// create a superblock
lfs_t lfs;
lfs_format(&lfs, cfg) => 0;
lfs_mount(&lfs, cfg) => 0;
lfs_file_t file;
lfs_file_open(&lfs, &file, "test",
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
lfs_file_write(&lfs, &file, "testtest", 8) => 8;
lfs_file_close(&lfs, &file) => 0;
lfs_unmount(&lfs) => 0;
// write an old minor version
//
// note we're messing around with internals to do this! this
// is not a user API
lfs_mount(&lfs, cfg) => 0;
lfs_mdir_t mdir;
lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
lfs_superblock_t superblock = {
.version = LFS_DISK_VERSION - 0x00000001,
.block_size = lfs.cfg->block_size,
.block_count = lfs.cfg->block_count,
.name_max = lfs.name_max,
.file_max = lfs.file_max,
.attr_max = lfs.attr_max,
};
lfs_superblock_tole32(&superblock);
lfs_dir_commit(&lfs, &mdir, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
&superblock})) => 0;
lfs_unmount(&lfs) => 0;
// mount should still work
lfs_mount(&lfs, cfg) => 0;
lfs_file_open(&lfs, &file, "test", LFS_O_RDONLY) => 0;
uint8_t buffer[8];
lfs_file_read(&lfs, &file, buffer, 8) => 8;
assert(memcmp(buffer, "testtest", 8) == 0);
lfs_file_close(&lfs, &file) => 0;
lfs_unmount(&lfs) => 0;
// if we write, we need to bump the minor version
lfs_mount(&lfs, cfg) => 0;
lfs_file_open(&lfs, &file, "test", LFS_O_WRONLY | LFS_O_TRUNC) => 0;
lfs_file_write(&lfs, &file, "teeeeest", 8) => 8;
lfs_file_close(&lfs, &file) => 0;
// minor version should have changed
lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
lfs_dir_get(&lfs, &mdir, LFS_MKTAG(0x7ff, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
&superblock)
=> LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock));
lfs_superblock_fromle32(&superblock);
assert((superblock.version >> 16) & 0xffff == LFS_DISK_VERSION_MAJOR);
assert((superblock.version >> 0) & 0xffff == LFS_DISK_VERSION_MINOR);
lfs_unmount(&lfs) => 0;
// and of course mount should still work
lfs_mount(&lfs, cfg) => 0;
lfs_file_open(&lfs, &file, "test", LFS_O_RDONLY) => 0;
lfs_file_read(&lfs, &file, buffer, 8) => 8;
assert(memcmp(buffer, "teeeeest", 8) == 0);
lfs_file_close(&lfs, &file) => 0;
// minor version should have changed
lfs_dir_fetch(&lfs, &mdir, (lfs_block_t[2]){0, 1}) => 0;
lfs_dir_get(&lfs, &mdir, LFS_MKTAG(0x7ff, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
&superblock)
=> LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock));
lfs_superblock_fromle32(&superblock);
assert((superblock.version >> 16) & 0xffff == LFS_DISK_VERSION_MAJOR);
assert((superblock.version >> 0) & 0xffff == LFS_DISK_VERSION_MINOR);
lfs_unmount(&lfs) => 0;
'''