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Add support for shrinking a filesystem

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This PR adds a new `lfs_fs_shrink`, which functions similarly to
`lfs_fs_grow`, but supports reducing the block count.

This functions first checks that none of the removed block are in use.
If it is the case, it will fail.
This commit is contained in:
Sosthène Guédon
2025-04-16 17:46:34 +02:00
parent 8ed63b27be
commit 2105e502c5
4 changed files with 288 additions and 22 deletions
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104
tests/test_shrink.toml Normal file
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@@ -0,0 +1,104 @@
# simple shrink
[cases.test_shrink_simple]
defines.BLOCK_COUNT = [10, 15, 20]
defines.AFTER_BLOCK_COUNT = [5, 10, 15, 19]
if = "AFTER_BLOCK_COUNT <= BLOCK_COUNT"
code = '''
lfs_t lfs;
lfs_format(&lfs, cfg) => 0;
lfs_mount(&lfs, cfg) => 0;
lfs_fs_shrink(&lfs, AFTER_BLOCK_COUNT) => 0;
lfs_unmount(&lfs);
if (BLOCK_COUNT != AFTER_BLOCK_COUNT) {
lfs_mount(&lfs, cfg) => LFS_ERR_INVAL;
}
lfs_t lfs2 = lfs;
struct lfs_config cfg2 = *cfg;
cfg2.block_count = AFTER_BLOCK_COUNT;
lfs2.cfg = &cfg2;
lfs_mount(&lfs2, &cfg2) => 0;
lfs_unmount(&lfs2) => 0;
'''
# shrinking full
[cases.test_shrink_full]
defines.BLOCK_COUNT = [10, 15, 20]
defines.AFTER_BLOCK_COUNT = [5, 7, 10, 12, 15, 17, 20]
defines.FILES_COUNT = [7, 8, 9, 10]
if = "AFTER_BLOCK_COUNT <= BLOCK_COUNT && FILES_COUNT + 2 < BLOCK_COUNT"
code = '''
lfs_t lfs;
lfs_format(&lfs, cfg) => 0;
// create FILES_COUNT files of BLOCK_SIZE - 50 bytes (to avoid inlining)
lfs_mount(&lfs, cfg) => 0;
for (int i = 0; i < FILES_COUNT + 1; i++) {
lfs_file_t file;
char path[1024];
sprintf(path, "file_%03d", i);
lfs_file_open(&lfs, &file, path,
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL) => 0;
char wbuffer[BLOCK_SIZE];
memset(wbuffer, 'b', BLOCK_SIZE);
// Ensure one block is taken per file, but that files are not inlined.
lfs_size_t size = BLOCK_SIZE - 0x40;
sprintf(wbuffer, "Hi %03d", i);
lfs_file_write(&lfs, &file, wbuffer, size) => size;
lfs_file_close(&lfs, &file) => 0;
}
int err = lfs_fs_shrink(&lfs, AFTER_BLOCK_COUNT);
if (err == 0) {
for (int i = 0; i < FILES_COUNT + 1; i++) {
lfs_file_t file;
char path[1024];
sprintf(path, "file_%03d", i);
lfs_file_open(&lfs, &file, path,
LFS_O_RDONLY ) => 0;
lfs_size_t size = BLOCK_SIZE - 0x40;
char wbuffer[size];
char wbuffer_ref[size];
// Ensure one block is taken per file, but that files are not inlined.
memset(wbuffer_ref, 'b', size);
sprintf(wbuffer_ref, "Hi %03d", i);
lfs_file_read(&lfs, &file, wbuffer, BLOCK_SIZE) => size;
lfs_file_close(&lfs, &file) => 0;
for (lfs_size_t j = 0; j < size; j++) {
wbuffer[j] => wbuffer_ref[j];
}
}
} else {
assert(err == LFS_ERR_NOTEMPTY);
}
lfs_unmount(&lfs) => 0;
if (err == 0 ) {
if ( AFTER_BLOCK_COUNT != BLOCK_COUNT ) {
lfs_mount(&lfs, cfg) => LFS_ERR_INVAL;
}
lfs_t lfs2 = lfs;
struct lfs_config cfg2 = *cfg;
cfg2.block_count = AFTER_BLOCK_COUNT;
lfs2.cfg = &cfg2;
lfs_mount(&lfs2, &cfg2) => 0;
for (int i = 0; i < FILES_COUNT + 1; i++) {
lfs_file_t file;
char path[1024];
sprintf(path, "file_%03d", i);
lfs_file_open(&lfs2, &file, path,
LFS_O_RDONLY ) => 0;
lfs_size_t size = BLOCK_SIZE - 0x40;
char wbuffer[size];
char wbuffer_ref[size];
// Ensure one block is taken per file, but that files are not inlined.
memset(wbuffer_ref, 'b', size);
sprintf(wbuffer_ref, "Hi %03d", i);
lfs_file_read(&lfs2, &file, wbuffer, BLOCK_SIZE) => size;
lfs_file_close(&lfs2, &file) => 0;
for (lfs_size_t j = 0; j < size; j++) {
wbuffer[j] => wbuffer_ref[j];
}
}
lfs_unmount(&lfs2);
}
'''

106
tests/test_superblocks.toml
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@@ -524,6 +524,112 @@ code = '''
lfs_unmount(&lfs) => 0;
'''
# mount and grow the filesystem
[cases.test_superblocks_shrink]
defines.BLOCK_COUNT = 'ERASE_COUNT'
defines.BLOCK_COUNT_2 = ['ERASE_COUNT/2', 'ERASE_COUNT/4', '2']
defines.KNOWN_BLOCK_COUNT = [true, false]
code = '''
lfs_t lfs;
lfs_format(&lfs, cfg) => 0;
if (KNOWN_BLOCK_COUNT) {
cfg->block_count = BLOCK_COUNT;
} else {
cfg->block_count = 0;
}
// mount with block_size < erase_size
lfs_mount(&lfs, cfg) => 0;
struct lfs_fsinfo fsinfo;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT);
lfs_unmount(&lfs) => 0;
// same size is a noop
lfs_mount(&lfs, cfg) => 0;
lfs_fs_shrink(&lfs, BLOCK_COUNT) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT);
lfs_unmount(&lfs) => 0;
lfs_mount(&lfs, cfg) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT);
lfs_unmount(&lfs) => 0;
// grow to new size
lfs_mount(&lfs, cfg) => 0;
lfs_fs_shrink(&lfs, BLOCK_COUNT_2) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT_2);
lfs_unmount(&lfs) => 0;
if (KNOWN_BLOCK_COUNT) {
cfg->block_count = BLOCK_COUNT_2;
} else {
cfg->block_count = 0;
}
lfs_mount(&lfs, cfg) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT_2);
lfs_unmount(&lfs) => 0;
// mounting with the previous size should fail
cfg->block_count = BLOCK_COUNT;
lfs_mount(&lfs, cfg) => LFS_ERR_INVAL;
if (KNOWN_BLOCK_COUNT) {
cfg->block_count = BLOCK_COUNT_2;
} else {
cfg->block_count = 0;
}
// same size is a noop
lfs_mount(&lfs, cfg) => 0;
lfs_fs_shrink(&lfs, BLOCK_COUNT_2) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT_2);
lfs_unmount(&lfs) => 0;
lfs_mount(&lfs, cfg) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT_2);
lfs_unmount(&lfs) => 0;
// do some work
lfs_mount(&lfs, cfg) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT_2);
lfs_file_t file;
lfs_file_open(&lfs, &file, "test",
LFS_O_CREAT | LFS_O_EXCL | LFS_O_WRONLY) => 0;
lfs_file_write(&lfs, &file, "hello!", 6) => 6;
lfs_file_close(&lfs, &file) => 0;
lfs_unmount(&lfs) => 0;
lfs_mount(&lfs, cfg) => 0;
lfs_fs_stat(&lfs, &fsinfo) => 0;
assert(fsinfo.block_size == BLOCK_SIZE);
assert(fsinfo.block_count == BLOCK_COUNT_2);
lfs_file_open(&lfs, &file, "test", LFS_O_RDONLY) => 0;
uint8_t buffer[256];
lfs_file_read(&lfs, &file, buffer, sizeof(buffer)) => 6;
lfs_file_close(&lfs, &file) => 0;
assert(memcmp(buffer, "hello!", 6) == 0);
lfs_unmount(&lfs) => 0;
'''
# test that metadata_max does not cause problems for superblock compaction
[cases.test_superblocks_metadata_max]
defines.METADATA_MAX = [