mirror of
https://github.com/eledio-devices/thirdparty-littlefs.git
synced 2025-10-31 00:32:38 +01:00
Combined superblock scan and fetch of xored-globals during mount
Conceptually these are two separate operations. However, they are both only needed during mount, both require iteration over the linked-list of metadata-pairs, and both are independent from each other. Combining these into one gives us a nice code savings. Additionally, this greatly simplifies the lookup of the root directory. Initially we used a flag to indicate which superblock was root, since we didn't want to fetch more pairs than we needed to. But since we're going to fetch all metadata-pairs anyways, we can just use the last superblock we find as the indicator of our root directory.
This commit is contained in:
Christopher Haster
157
lfs.c
157
lfs.c
@@ -3116,7 +3116,7 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
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lfs_superblock_tole32(&superblock);
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err = lfs_dir_commit(lfs, &root,
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LFS_MKATTR(LFS_TYPE_ROOT, 0, &superblock, sizeof(superblock),
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LFS_MKATTR(LFS_TYPE_SUPERBLOCK, 0, &superblock, sizeof(superblock),
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NULL));
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if (err) {
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goto cleanup;
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@@ -3139,97 +3139,94 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
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return err;
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}
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// find root/superblock
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lfs_mdir_t root;
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lfs_superblock_t superblock;
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lfs_stag_t tag = lfs_dir_findmatch(lfs,
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&root, (const lfs_block_t[2]){0, 1}, false, 0x7fc00000,
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LFS_MKTAG(LFS_TYPE_ROOT, 0, 8),
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lfs_dir_find_match, &(struct lfs_dir_find_match){
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lfs, "littlefs", 8});
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if (tag < 0) {
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err = tag;
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goto cleanup;
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}
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lfs_stag_t res = lfs_dir_get(lfs, &root, 0x7f800000,
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LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, sizeof(superblock)),
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&superblock);
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if (res < 0) {
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err = res;
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goto cleanup;
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}
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lfs_superblock_fromle32(&superblock);
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lfs->root[0] = root.pair[0];
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lfs->root[1] = root.pair[1];
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// check version
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uint16_t major_version = (0xffff & (superblock.version >> 16));
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uint16_t minor_version = (0xffff & (superblock.version >> 0));
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if ((major_version != LFS_DISK_VERSION_MAJOR ||
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minor_version > LFS_DISK_VERSION_MINOR)) {
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LFS_ERROR("Invalid version %"PRIu32".%"PRIu32,
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major_version, minor_version);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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// check superblock configuration
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if (superblock.attr_max) {
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if (superblock.attr_max > lfs->attr_max) {
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LFS_ERROR("Unsupported attr_max (%"PRIu32" > %"PRIu32")",
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superblock.attr_max, lfs->attr_max);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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lfs->attr_max = superblock.attr_max;
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}
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if (superblock.name_max) {
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if (superblock.name_max > lfs->name_max) {
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LFS_ERROR("Unsupported name_max (%"PRIu32" > %"PRIu32")",
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superblock.name_max, lfs->name_max);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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lfs->name_max = superblock.name_max;
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}
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if (superblock.inline_max) {
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if (superblock.inline_max > lfs->inline_max) {
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LFS_ERROR("Unsupported inline_max (%"PRIu32" > %"PRIu32")",
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superblock.inline_max, lfs->inline_max);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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lfs->inline_max = superblock.inline_max;
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}
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// scan for any global updates
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// scan directory blocks for superblock and any global updates
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lfs_mdir_t dir = {.tail = {0, 1}};
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while (!lfs_pair_isnull(dir.tail)) {
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res = lfs_dir_fetchmatch(lfs, &dir, dir.tail, 0x7c000000,
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LFS_MKTAG(LFS_TYPE_GLOBALS, 0, 10), NULL, NULL);
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// fetch next block in tail list
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lfs_stag_t res = lfs_dir_fetchmatch(lfs, &dir, dir.tail, 0x7fc00000,
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LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, 8),
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lfs_dir_find_match, &(struct lfs_dir_find_match){
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lfs, "littlefs", 8});
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if (res < 0) {
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err = LFS_ERR_INVAL;
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err = res;
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goto cleanup;
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}
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// has superblock?
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if (res) {
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lfs_global_t locals;
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res = lfs_dir_get(lfs, &dir, 0x7c000000,
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LFS_MKTAG(LFS_TYPE_GLOBALS, 0, 10), &locals);
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// update root
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lfs->root[0] = dir.pair[0];
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lfs->root[1] = dir.pair[1];
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// grab superblock
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lfs_superblock_t superblock;
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res = lfs_dir_get(lfs, &dir, 0x7f800000,
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LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, sizeof(superblock)),
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&superblock);
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if (res < 0) {
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err = res;
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goto cleanup;
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}
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locals.l.deorphaned = (lfs_tag_type(res) & 1);
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lfs_superblock_fromle32(&superblock);
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// xor together indirect deletes
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// check version
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uint16_t major_version = (0xffff & (superblock.version >> 16));
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uint16_t minor_version = (0xffff & (superblock.version >> 0));
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if ((major_version != LFS_DISK_VERSION_MAJOR ||
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minor_version > LFS_DISK_VERSION_MINOR)) {
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LFS_ERROR("Invalid version %"PRIu32".%"PRIu32,
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major_version, minor_version);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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// check superblock configuration
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if (superblock.attr_max) {
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if (superblock.attr_max > lfs->attr_max) {
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LFS_ERROR("Unsupported attr_max (%"PRIu32" > %"PRIu32")",
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superblock.attr_max, lfs->attr_max);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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lfs->attr_max = superblock.attr_max;
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}
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if (superblock.name_max) {
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if (superblock.name_max > lfs->name_max) {
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LFS_ERROR("Unsupported name_max (%"PRIu32" > %"PRIu32")",
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superblock.name_max, lfs->name_max);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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lfs->name_max = superblock.name_max;
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}
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if (superblock.inline_max) {
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if (superblock.inline_max > lfs->inline_max) {
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LFS_ERROR("Unsupported inline_max (%"PRIu32" > %"PRIu32")",
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superblock.inline_max, lfs->inline_max);
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err = LFS_ERR_INVAL;
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goto cleanup;
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}
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lfs->inline_max = superblock.inline_max;
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}
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}
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// has globals?
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lfs_global_t locals;
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res = lfs_dir_get(lfs, &dir, 0x7c000000,
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LFS_MKTAG(LFS_TYPE_GLOBALS, 0, 10), &locals);
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if (res < 0 && res != LFS_ERR_NOENT) {
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err = res;
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goto cleanup;
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}
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if (res != LFS_ERR_NOENT) {
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locals.l.deorphaned = (lfs_tag_type(res) & 1);
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// xor together to find resulting globals
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lfs_global_xor(&lfs->locals, &locals);
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}
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}
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8
lfs.h
8
lfs.h
@@ -94,27 +94,25 @@ enum lfs_type {
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// internally used types
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LFS_TYPE_USER = 0x100,
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LFS_TYPE_SUPERBLOCK = 0x001,
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LFS_TYPE_ROOT = 0x000,
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LFS_TYPE_NAME = 0x000,
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LFS_TYPE_DELETE = 0x020,
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LFS_TYPE_STRUCT = 0x040,
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LFS_TYPE_GLOBALS = 0x0e0,
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LFS_TYPE_TAIL = 0x080,
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LFS_TYPE_SOFTTAIL = 0x080,
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LFS_TYPE_HARDTAIL = 0x081,
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LFS_TYPE_CRC = 0x0a0,
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LFS_TYPE_SUPERBLOCK = 0x001,
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LFS_TYPE_GLOBALS = 0x0e0,
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LFS_TYPE_DIRSTRUCT = 0x040,
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LFS_TYPE_INLINESTRUCT = 0x041,
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LFS_TYPE_CTZSTRUCT = 0x042,
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// internal chip sources
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LFS_FROM_REGION = 0x000,
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LFS_FROM_MEM = 0x000,
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LFS_FROM_DISK = 0x200,
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LFS_FROM_MOVE = 0x0c1,
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LFS_FROM_USERATTRS = 0x0c2,
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LFS_FROM_SUPERBLOCK = 0x0c3,
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};
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// File open flags
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@@ -7,7 +7,6 @@ TYPES = {
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(0x1ff, 0x002): 'reg',
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(0x1ff, 0x003): 'dir',
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(0x1ff, 0x001): 'superblock',
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(0x1ff, 0x000): 'root',
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(0x1ff, 0x020): 'delete',
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(0x1f0, 0x0e0): 'globals',
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(0x1ff, 0x080): 'tail soft',
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