Github/littlefs
1
Fork 0
Code Actions Activity

Reworked lfsr_mtree_pathlookup a bit to better leverage internal errors

Browse Source 
This avoids implicit info, mid.mid=-1 implying a bad path, and mid.mid=0
implying the root directory, at a tradeoff of potentially making the
returned error codes a bit confusing (0 means the file is NOT found!).

Here are the now possible return codes, aside from lower-level errors
(IO, CORRUPT, etc):

- 0      => path is valid, file NOT found
- EXIST  => path is valid, file found
- INVAL  => path is valid, but points to root
- NOENT  => path is NOT valid, intermediate dir missing
- NOTDIR => path is NOT valid, intermediate dir is not a dir

Since the root has no real mdir entry, I think the special INVAL return
code is warranted. It needs special behavior in relevant functions
anyways.

Note that orphaned files still need special handling.

Code changes:

            code          stack
  before:  33944           2944
  after:   34036 (+0.3%)   2944 (+0.0%)
This commit is contained in:
Christopher Haster
2024-01-18 15:16:00 -06:00
parent a17b5e3cd6
commit 942427dc8c
3 changed files with 102 additions and 113 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lfs.c
+77 -88
View File
@@ -4939,11 +4939,6 @@ static inline lfsr_srid_t lfsr_mid_rid(lfs_t *lfs, lfsr_smid_t mid) {
| (mid & ((1 << lfs->mbits) - 1));
}
// we use the root's bookmark at 0.0 to represent root
static inline bool lfsr_mid_isroot(lfsr_smid_t mid) {
return mid == 0;
}
// metadata-pointer things
@@ -5022,10 +5017,6 @@ static inline lfsr_srid_t lfsr_mdir_rid(lfs_t *lfs, const lfsr_mdir_t *mdir) {
return lfsr_mid_rid(lfs, mdir->mid);
}
static inline bool lfsr_mdir_isroot(const lfsr_mdir_t *mdir) {
return lfsr_mid_isroot(mdir->mid);
}
// mdir operations
static int lfsr_mdir_fetch(lfs_t *lfs, lfsr_mdir_t *mdir,
lfsr_smid_t mid, const lfsr_mptr_t *mptr) {
@@ -6920,44 +6911,45 @@ enum {
LFSR_DID_ROOT = 0,
};
// TODO this function may need another look over
//
// lookup full paths in our mtree
//
// note the errors here are a bit weird, because paths can have some weird
// corner-cases during lookup, and we want to report all the different
// conditions:
//
// - 0 => path is valid, file NOT found
// - EXIST => path is valid, file found
// - INVAL => path is valid, but points to root
// - NOENT => path is NOT valid, intermediate dir missing
// - NOTDIR => path is NOT valid, intermediate dir is not a dir
//
// if not found, mdir_/did_/name_ will at least be set up
// with what should be the parent
static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
// TODO originally path itself was a double pointer, is that a
// better design?
lfsr_mdir_t *mdir_, lfsr_tag_t *tag_,
lfsr_did_t *did_, const char **name_, lfs_size_t *name_size_) {
// setup root
lfsr_mdir_t mdir = {.mid = 0};
lfsr_mdir_t mdir = {.mid = -1};
lfsr_tag_t tag = LFSR_TAG_DIR;
lfsr_did_t did = LFSR_DID_ROOT;
// use mid=-1 to indicate we can't even create the path
if (mdir_) {
mdir_->mid = -1;
}
// we reduce path to a single name if we can find it
const char *name = path;
lfs_size_t name_size = 0;
while (true) {
// skip slashes
name += strspn(name, "/");
lfs_size_t name_size = strcspn(name, "/");
path += strspn(path, "/");
lfs_size_t name_size__ = strcspn(path, "/");
// skip '.' and root '..'
if ((name_size == 1 && memcmp(name, ".", 1) == 0)
|| (name_size == 2 && memcmp(name, "..", 2) == 0)) {
name += name_size;
if ((name_size__ == 1 && memcmp(path, ".", 1) == 0)
|| (name_size__ == 2 && memcmp(path, "..", 2) == 0)) {
path += name_size__;
goto next;
}
// skip if matched by '..' in name
const char *suffix = name + name_size;
const char *suffix = path + name_size__;
lfs_size_t suffix_size;
int depth = 1;
while (true) {
@@ -6970,7 +6962,7 @@ static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
if (suffix_size == 2 && memcmp(suffix, "..", 2) == 0) {
depth -= 1;
if (depth == 0) {
name = suffix + suffix_size;
path = suffix + suffix_size;
goto next;
}
} else {
@@ -6981,15 +6973,34 @@ static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
}
// found end of path, we must be done parsing our path now
if (name[0] == '\0') {
if (path[0] == '\0') {
// the root dir doesn't have an mdir really, so it's always
// a special case
if (mdir.mid == -1) {
return LFS_ERR_INVAL;
}
if (mdir_) {
*mdir_ = mdir;
}
if (tag_) {
*tag_ = tag;
}
return 0;
if (did_) {
*did_ = did;
}
if (name_) {
*name_ = name;
}
if (name_size_) {
*name_size_ = name_size;
}
return LFS_ERR_EXIST;
}
// found another name
name = path;
name_size = name_size__;
// only continue if we hit a directory
if (tag != LFSR_TAG_DIR) {
@@ -6999,7 +7010,7 @@ static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
}
// read the next did from the mdir if this is not the root
if (!lfsr_mid_isroot(mdir.mid)) {
if (mdir.mid != -1) {
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, &mdir, mdir.mid, LFSR_TAG_DID,
&data);
@@ -7016,12 +7027,9 @@ static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
// lookup up this name in the mtree
int err = lfsr_mtree_namelookup(lfs, did, name, name_size,
&mdir, &tag, NULL);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// keep track of where to insert if we are the last name in our path
if (strchr(name, '/') == NULL) {
if (err) {
// report where to insert if we are the last name in our path
if (err == LFS_ERR_NOENT && strchr(name, '/') == NULL) {
if (mdir_) {
*mdir_ = mdir;
}
@@ -7037,16 +7045,14 @@ static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
if (name_size_) {
*name_size_ = name_size;
}
return 0;
}
// error if not found
if (err == LFS_ERR_NOENT) {
return LFS_ERR_NOENT;
return err;
}
// go on to next name
name += name_size;
next:;
path += name_size;
next:;
}
}
@@ -8403,12 +8409,11 @@ int lfsr_mkdir(lfs_t *lfs, const char *path) {
err = lfsr_mtree_pathlookup(lfs, path,
&mdir, &tag,
&did, &name, &name_size);
if (err && (err != LFS_ERR_NOENT || mdir.mid == -1)) {
if (err && err != LFS_ERR_EXIST) {
return err;
}
// already exists? note orphans don't really exist
bool exists = (err != LFS_ERR_NOENT);
bool exists = (err == LFS_ERR_EXIST);
if (exists && tag != LFSR_TAG_ORPHAN) {
return LFS_ERR_EXIST;
}
@@ -8539,21 +8544,14 @@ int lfsr_remove(lfs_t *lfs, const char *path) {
err = lfsr_mtree_pathlookup(lfs, path,
&mdir, &tag,
&did, &name, &name_size);
if (err) {
if (err && err != LFS_ERR_EXIST) {
return err;
}
// found a zombie?
if (tag == LFSR_TAG_ORPHAN) {
// don't worry, zombies aren't real and cannot hurt you
// doesn't exist? note orphans don't really exist
if (!err || tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// as funny as it would be, you can't remove the root
if (lfsr_mdir_isroot(&mdir)) {
return LFS_ERR_INVAL;
}
// if we're removing a directory, we need to also remove the
// bookmark entry
lfsr_grm_t grm = lfs->grm;
@@ -8661,21 +8659,14 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
err = lfsr_mtree_pathlookup(lfs, old_path,
&old_mdir, &old_tag,
NULL, NULL, NULL);
if (err) {
if (err && err != LFS_ERR_EXIST) {
return err;
}
// found a zombie?
if (old_tag == LFSR_TAG_ORPHAN) {
// don't worry, zombies aren't real and cannot hurt you
// doesn't exist? note orphans don't really exist
if (!err || old_tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// as funny as it would be, you can't rename the root
if (lfsr_mdir_isroot(&old_mdir)) {
return LFS_ERR_INVAL;
}
// mark old entry for removal with a grm
lfsr_grm_t grm = lfs->grm;
lfsr_grm_pushrm(&grm, old_mdir.mid);
@@ -8689,11 +8680,11 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
err = lfsr_mtree_pathlookup(lfs, new_path,
&new_mdir, &new_tag,
&new_did, &new_name, &new_name_size);
if (err && (err != LFS_ERR_NOENT || new_mdir.mid == -1)) {
if (err && err != LFS_ERR_EXIST) {
return err;
}
// already exists?
bool exists = (err != LFS_ERR_NOENT);
bool exists = (err == LFS_ERR_EXIST);
// there are a few cases we need to watch out for
if (!exists) {
@@ -8866,17 +8857,16 @@ int lfsr_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
int err = lfsr_mtree_pathlookup(lfs, path,
&mdir, &tag,
NULL, &name, &name_size);
if (err) {
if (err && err != LFS_ERR_EXIST && err != LFS_ERR_INVAL) {
return err;
}
// pretend orphans don't exist
if (tag == LFSR_TAG_ORPHAN) {
// doesn't exist? note orphans don't really exist
if (!err || tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// special case for root
if (lfsr_mdir_isroot(&mdir)) {
if (err == LFS_ERR_INVAL) {
strcpy(info->name, "/");
info->type = LFS_TYPE_DIR;
return 0;
@@ -8895,26 +8885,24 @@ int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
int err = lfsr_mtree_pathlookup(lfs, path,
&mdir, &tag,
NULL, NULL, NULL);
if (err) {
if (err && err != LFS_ERR_EXIST && err != LFS_ERR_INVAL) {
return err;
}
// are we a directory?
if (tag != LFSR_TAG_DIR) {
if (tag == LFSR_TAG_ORPHAN) {
// doesn't exist? note orphans don't really exist
if (!err || tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
} else {
return LFS_ERR_NOTDIR;
}
}
// setup dir state
dir->type = LFS_TYPE_DIR;
// read our did from the mdir, unless we're root
if (lfsr_mdir_isroot(&mdir)) {
if (err == LFS_ERR_INVAL) {
dir->did = 0;
} else {
// not a directory?
if (tag != LFSR_TAG_DIR) {
return LFS_ERR_NOTDIR;
}
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &mdir, mdir.mid, LFSR_TAG_DID,
&data);
@@ -8936,6 +8924,7 @@ int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
}
// add to tracked mdirs
dir->type = LFS_TYPE_DIR;
lfsr_addopened(lfs, (lfsr_opened_t*)dir);
return 0;
}
@@ -9224,7 +9213,6 @@ int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
}
// setup file state
file->type = LFS_TYPE_REG;
file->flags = flags;
file->cfg = cfg;
file->pos = 0;
@@ -9239,12 +9227,12 @@ int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
int err = lfsr_mtree_pathlookup(lfs, path,
&file->mdir, &tag,
&did, &name, &name_size);
if (err && (err != LFS_ERR_NOENT || file->mdir.mid == -1)) {
if (err && err != LFS_ERR_EXIST) {
return err;
}
// creating a new entry?
if (err == LFS_ERR_NOENT || tag == LFSR_TAG_ORPHAN) {
if (!err || tag == LFSR_TAG_ORPHAN) {
if (!lfsr_o_iscreat(flags)) {
return LFS_ERR_NOENT;
}
@@ -9257,7 +9245,7 @@ int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
// create an orphan entry if we don't have one, this reserves the
// mid until first sync
if (err == LFS_ERR_NOENT) {
if (!err) {
err = lfsr_mdir_commit(lfs, &file->mdir, LFSR_ATTRS(
LFSR_ATTR(file->mdir.mid,
ORPHAN, +1, CAT(
@@ -9361,6 +9349,7 @@ int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
}
// add to tracked mdirs
file->type = LFS_TYPE_REG;
lfsr_addopened(lfs, (lfsr_opened_t*)file);
return 0;
tests/test_dirs.toml
+2 -2
View File
@@ -281,14 +281,14 @@ code = '''
}
// try to make root, which doesn't make sense
lfsr_mkdir(&lfs, "/") => LFS_ERR_EXIST;
lfsr_mkdir(&lfs, "/") => LFS_ERR_INVAL;
// make a directory
err = lfsr_mkdir(&lfs, "ardvark");
assert(!err || (TEST_PLS && err == LFS_ERR_EXIST));
// try to make root, which doesn't make sense
lfsr_mkdir(&lfs, "/") => LFS_ERR_EXIST;
lfsr_mkdir(&lfs, "/") => LFS_ERR_INVAL;
// remount?
if (REMOUNT) {
tests/test_files.toml
+7 -7
View File
@@ -426,16 +426,16 @@ code = '''
// try reading our root as a file
lfsr_file_t file;
lfsr_file_open(&lfs, &file, "/", LFS_O_RDONLY) => LFS_ERR_ISDIR;
lfsr_file_open(&lfs, &file, "/", LFS_O_RDONLY) => LFS_ERR_INVAL;
// try writing our root as a file
lfsr_file_open(&lfs, &file, "/", LFS_O_WRONLY) => LFS_ERR_ISDIR;
lfsr_file_open(&lfs, &file, "/", LFS_O_WRONLY) => LFS_ERR_INVAL;
lfsr_file_open(&lfs, &file, "/",
LFS_O_WRONLY | LFS_O_TRUNC) => LFS_ERR_ISDIR;
LFS_O_WRONLY | LFS_O_TRUNC) => LFS_ERR_INVAL;
lfsr_file_open(&lfs, &file, "/",
LFS_O_WRONLY | LFS_O_CREAT) => LFS_ERR_ISDIR;
LFS_O_WRONLY | LFS_O_CREAT) => LFS_ERR_INVAL;
lfsr_file_open(&lfs, &file, "/",
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => LFS_ERR_ISDIR;
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => LFS_ERR_INVAL;
// try rename a file on top of our directory
lfsr_file_open(&lfs, &file, "not_hello",
@@ -446,7 +446,7 @@ code = '''
lfsr_file_write(&lfs, &file, wbuf, wsize) => wsize;
lfsr_file_close(&lfs, &file) => 0;
lfsr_rename(&lfs, "not_hello", "/") => LFS_ERR_ISDIR;
lfsr_rename(&lfs, "not_hello", "/") => LFS_ERR_INVAL;
// remount?
if (REMOUNT) {
@@ -1734,7 +1734,7 @@ code = '''
}
// rename the file
lfsr_rename(&lfs, "amethyst", "/") => LFS_ERR_ISDIR;
lfsr_rename(&lfs, "amethyst", "/") => LFS_ERR_INVAL;
// remount?
if (REMOUNT) {