Github/littlefs
1
Fork 0
Code Actions Activity

Dropped lfsr_dir_t's bookmark mdir, switched to did for dir updates

Browse Source 
This simplification comes from the observation that we don't actually
need to know the bookmark's mid to know if a given operation is in a
dir's range, just the dir's did. And since dids are immutable, we don't
need another opened-list entry or other shenanigans.

A dir's did is a bit harder to access, requiring a name lookup, but we
conveniently already fetch these in all relevant functions as a part of
path resolution.

This does mean more opened-list logic in the high-level functions:

  function              can zombie  can create  can remove
  lfsr_mkdir                     y           y           n
  lfsr_rename                    y           y           y
  lfsr_remove                    y           n           y
  lfsr_file_opencfg              y           y           n

But I think this actually results in better code readability, since the
opened-list logic and high-level logic are closely related. I went ahead
and lifted the similar orphan/zombie opened-list logic up to this level
for this reason.

Unfortunately lifting this logic does result in a higher code cost, but
I think this is worth it for better readability and a significantly
reduced RAM cost for lfsr_dir_ts. Keep in mind these will probably
become very common for the future planned openat/*at functions:

           code          stack          lfsr_dir_t
  before: 33402           2632                  80
  after:  33582 (+0.5%)   2632 (+0.0%)          44 (-45.0%)

Also added a new test case, test_dread_read_rm_remkdir, to catch the
mistake of thinking the did is unique even when the dir is removed,
since that is now a concern.
This commit is contained in:
Christopher Haster
2024-05-17 14:59:57 -05:00
parent fb73eb12e8
commit aa1d2f0cf9
3 changed files with 225 additions and 75 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lfs.c
+119 -73
View File
@@ -5293,15 +5293,6 @@ static inline const lfsr_dir_t *lfsr_opened_constdir(
return (lfsr_dir_t*)o;
}
static inline lfsr_dir_t *lfsr_opened_bookmark(lfsr_opened_t *o) {
return (lfsr_dir_t*)(o - 1);
}
static inline const lfsr_dir_t *lfsr_opened_constbookmark(
const lfsr_opened_t *o) {
return (const lfsr_dir_t*)(o - 1);
}
static inline lfsr_file_t *lfsr_opened_file(lfsr_opened_t *o) {
return (lfsr_file_t*)((struct lfs_file_config**)o - 1);
}
@@ -7102,34 +7093,17 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
// adjust opened mdirs?
if (lfsr_mdir_cmp(&o->mdir, mdir) == 0
&& o->mdir.mid >= mid) {
// replaced?
if (o->mdir.mid == mid - attrs[i].weight
&& lfsr_tag_issup(attrs[i].tag)) {
o->flags |= LFS_F_ZOMBIE
| LFS_F_UNSYNC
| LFS_O_DESYNC;
o->flags &= ~LFS_F_ORPHAN;
// removed?
} else if (o->mdir.mid < mid - attrs[i].weight) {
if (o->mdir.mid < mid - attrs[i].weight) {
// we should not be removing opened regular files
LFS_ASSERT(o->type != LFS_TYPE_REG);
o->flags |= LFS_F_ZOMBIE;
if (o->type == LFS_TYPE_DIR) {
lfsr_opened_dir(o)->pos
+= (mid - attrs[i].weight) - o->mdir.mid;
}
o->mdir.mid = mid;
} else {
o->mdir.mid += attrs[i].weight;
// adjust dir position?
if (o->type == LFS_TYPE_DIR) {
lfsr_opened_dir(o)->pos += attrs[i].weight;
} else if (o->type == LFS_TYPE_BOOKMARK) {
lfsr_opened_bookmark(o)->pos -= attrs[i].weight;
}
}
} else if (o->mdir.mid > mid) {
// adjust dir position?
if (o->type == LFS_TYPE_DIR) {
lfsr_opened_dir(o)->pos += attrs[i].weight;
} else if (o->type == LFS_TYPE_BOOKMARK) {
lfsr_opened_bookmark(o)->pos -= attrs[i].weight;
}
}
}
@@ -9060,6 +9034,26 @@ int lfsr_mkdir(lfs_t *lfs, const char *path) {
return err;
}
// update in-device state
for (lfsr_opened_t *o = lfs->opened; o; o = o->next) {
// mark any clobbered orphans as zombied
if (exists
&& o->type == LFS_TYPE_REG
&& o->mdir.mid == mdir.mid) {
o->flags = (o->flags & ~LFS_F_ORPHAN)
| LFS_F_ZOMBIE
| LFS_F_UNSYNC
| LFS_O_DESYNC;
// update dir positions
} else if (!exists
&& o->type == LFS_TYPE_DIR
&& lfsr_opened_dir(o)->did == did
&& o->mdir.mid >= mdir.mid) {
lfsr_opened_dir(o)->pos += 1;
}
}
return 0;
}
@@ -9090,6 +9084,7 @@ int lfsr_remove(lfs_t *lfs, const char *path) {
// if we're removing a directory, we need to also remove the
// bookmark entry
lfsr_grm_t grm = lfs->grm;
lfsr_did_t did_ = 0;
if (tag == LFSR_TAG_DIR) {
// first lets figure out the did
lfsr_data_t data;
@@ -9099,8 +9094,7 @@ int lfsr_remove(lfs_t *lfs, const char *path) {
return err;
}
lfsr_did_t did;
err = lfsr_data_readleb128(lfs, &data, &did);
err = lfsr_data_readleb128(lfs, &data, &did_);
if (err) {
return err;
}
@@ -9108,7 +9102,7 @@ int lfsr_remove(lfs_t *lfs, const char *path) {
// then lookup the bookmark entry
lfsr_mdir_t bookmark_mdir;
err = lfsr_mtree_namelookup(lfs, &lfs->mtree,
did, NULL, 0,
did_, NULL, 0,
&bookmark_mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
@@ -9164,12 +9158,28 @@ int lfsr_remove(lfs_t *lfs, const char *path) {
return err;
}
// lfsr_mdir_commit implicitly marks removed files as zombied, but
// we also need to mark them as uncreate to indicate that the mid
// needs to be cleaned up on close
// update in-device state
for (lfsr_opened_t *o = lfs->opened; o; o = o->next) {
if (o->type == LFS_TYPE_REG && o->mdir.mid == mdir.mid) {
o->flags |= LFS_F_ORPHAN;
// mark any clobbered orphans as zombied orphans
if (zombie
&& o->type == LFS_TYPE_REG
&& o->mdir.mid == mdir.mid) {
o->flags |= LFS_F_ORPHAN
| LFS_F_ZOMBIE
| LFS_F_UNSYNC
| LFS_O_DESYNC;
// mark any removed dirs as zombies
} else if (did_
&& o->type == LFS_TYPE_DIR
&& lfsr_opened_dir(o)->did == did_) {
o->flags |= LFS_F_ZOMBIE;
// update dir positions
} else if (o->type == LFS_TYPE_DIR
&& lfsr_opened_dir(o)->did == did
&& o->mdir.mid >= mdir.mid) {
lfsr_opened_dir(o)->pos -= 1;
}
}
@@ -9188,9 +9198,10 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
// lookup old entry
lfsr_mdir_t old_mdir;
lfsr_tag_t old_tag;
lfsr_did_t old_did;
err = lfsr_mtree_pathlookup(lfs, &lfs->mtree, old_path,
&old_mdir, &old_tag,
NULL, NULL, NULL);
&old_did, NULL, NULL);
if (err && err != LFS_ERR_EXIST) {
return err;
}
@@ -9217,6 +9228,7 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
}
// already exists?
bool exists = (err == LFS_ERR_EXIST);
lfsr_did_t new_did_ = 0;
// there are a few cases we need to watch out for
if (!exists) {
@@ -9259,8 +9271,7 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
return err;
}
lfsr_did_t did;
err = lfsr_data_readleb128(lfs, &data, &did);
err = lfsr_data_readleb128(lfs, &data, &new_did_);
if (err) {
return err;
}
@@ -9268,7 +9279,7 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
// then lookup the bookmark entry
lfsr_mdir_t bookmark_mdir;
err = lfsr_mtree_namelookup(lfs, &lfs->mtree,
did, NULL, 0,
new_did_, NULL, 0,
&bookmark_mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
@@ -9311,11 +9322,42 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
return err;
}
// update moved files with the new mdir
// update in-device state
for (lfsr_opened_t *o = lfs->opened; o; o = o->next) {
if (o->type == LFS_TYPE_REG
// mark any clobbered orphans as zombied
if (exists
&& o->type == LFS_TYPE_REG
&& o->mdir.mid == new_mdir.mid) {
o->flags = (o->flags & ~LFS_F_ORPHAN)
| LFS_F_ZOMBIE
| LFS_F_UNSYNC
| LFS_O_DESYNC;
// update moved files with the new mdir
} else if (o->type == LFS_TYPE_REG
// TODO can we avoid this double check?
&& lfsr_grm_isrm(&lfs->grm, o->mdir.mid)) {
o->mdir = new_mdir;
// mark any removed dirs as zombies
} else if (new_did_
&& o->type == LFS_TYPE_DIR
&& lfsr_opened_dir(o)->did == new_did_) {
o->flags |= LFS_F_ZOMBIE;
// update dir positions
} else if (o->type == LFS_TYPE_DIR) {
if (!exists
&& lfsr_opened_dir(o)->did == new_did
&& o->mdir.mid >= new_mdir.mid) {
lfsr_opened_dir(o)->pos += 1;
}
if (lfsr_opened_dir(o)->did == old_did
&& o->mdir.mid >= lfs->grm.rms[0]) {
lfsr_opened_dir(o)->pos -= 1;
}
}
}
@@ -9405,10 +9447,8 @@ int lfsr_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
// setup dir state
dir->p.type = LFS_TYPE_DIR;
dir->p.flags = 0;
dir->b.type = LFS_TYPE_BOOKMARK;
dir->b.flags = 0;
dir->m.type = LFS_TYPE_DIR;
dir->m.flags = 0;
// lookup our directory
lfsr_mdir_t mdir;
@@ -9447,15 +9487,6 @@ int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
}
}
// lookup our bookmark in the mtree
err = lfsr_mtree_namelookup(lfs, &lfs->mtree,
dir->did, NULL, 0,
&dir->b.mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// let rewind initialize the pos state
err = lfsr_dir_rewind(lfs, dir);
if (err) {
@@ -9463,21 +9494,19 @@ int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
}
// add to tracked mdirs
lfsr_opened_add(lfs, &dir->p);
lfsr_opened_add(lfs, &dir->b);
lfsr_opened_add(lfs, &dir->m);
return 0;
}
int lfsr_dir_close(lfs_t *lfs, lfsr_dir_t *dir) {
// remove from tracked mdirs
lfsr_opened_remove(lfs, &dir->p);
lfsr_opened_remove(lfs, &dir->b);
lfsr_opened_remove(lfs, &dir->m);
return 0;
}
int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
// was our dir removed?
if (lfsr_f_iszombie(dir->b.flags)) {
if (lfsr_f_iszombie(dir->m.flags)) {
return LFS_ERR_NOENT;
}
@@ -9497,7 +9526,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
}
// seek in case our mdir was dropped
int err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->p.mdir, 0);
int err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->m.mdir, 0);
if (err) {
return err;
}
@@ -9506,7 +9535,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
// lookup the next name tag
lfsr_tag_t tag;
lfsr_data_t data;
err = lfsr_mdir_sublookup(lfs, &dir->p.mdir, LFSR_TAG_NAME,
err = lfsr_mdir_sublookup(lfs, &dir->m.mdir, LFSR_TAG_NAME,
&tag, &data);
if (err) {
return err;
@@ -9527,7 +9556,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
// skip orphans, we pretend these don't exist
if (tag != LFSR_TAG_ORPHAN) {
// fill out our info struct
err = lfsr_stat_(lfs, &dir->p.mdir, tag, data,
err = lfsr_stat_(lfs, &dir->m.mdir, tag, data,
info);
if (err) {
return err;
@@ -9535,7 +9564,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
}
// eagerly look up the next entry
err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->p.mdir, 1);
err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->m.mdir, 1);
if (err && err != LFS_ERR_NOENT) {
return err;
}
@@ -9549,7 +9578,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
int lfsr_dir_seek(lfs_t *lfs, lfsr_dir_t *dir, lfs_soff_t off) {
// do nothing if removed
if (lfsr_f_iszombie(dir->b.flags)) {
if (lfsr_f_iszombie(dir->m.flags)) {
return 0;
}
@@ -9564,7 +9593,7 @@ int lfsr_dir_seek(lfs_t *lfs, lfsr_dir_t *dir, lfs_soff_t off) {
//
// note the -2 to adjust for dot entries
if (off > 2) {
err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->p.mdir, off - 2);
err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->m.mdir, off - 2);
if (err && err != LFS_ERR_NOENT) {
return err;
}
@@ -9581,16 +9610,24 @@ lfs_soff_t lfsr_dir_tell(lfs_t *lfs, lfsr_dir_t *dir) {
int lfsr_dir_rewind(lfs_t *lfs, lfsr_dir_t *dir) {
// do nothing if removed
if (lfsr_f_iszombie(dir->b.flags)) {
if (lfsr_f_iszombie(dir->m.flags)) {
return 0;
}
// reset pos
dir->pos = 0;
// copy bookmark mdir and eagerly lookup the next entry
dir->p.mdir = dir->b.mdir;
int err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->p.mdir, 1);
// lookup our bookmark in the mtree
int err = lfsr_mtree_namelookup(lfs, &lfs->mtree,
dir->did, NULL, 0,
&dir->m.mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// eagerly lookup the next entry
err = lfsr_mtree_seek(lfs, &lfs->mtree, &dir->m.mdir, 1);
if (err && err != LFS_ERR_NOENT) {
return err;
}
@@ -9804,6 +9841,15 @@ int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
if (err) {
return err;
}
// update dir positions
for (lfsr_opened_t *o = lfs->opened; o; o = o->next) {
if (o->type == LFS_TYPE_DIR
&& lfsr_opened_dir(o)->did == did
&& o->mdir.mid >= file->m.mdir.mid) {
lfsr_opened_dir(o)->pos += 1;
}
}
}
// mark as unsync and uncreat, we need to convert to reg file