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Separated out version of dir remove/append for non-entries
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This allows updates to directories without needing to allocate an entry
struct for every call.
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@geky
geky committed Oct 10, 2018
1 parent 362b0bb commit 03b262b
Showing 1 changed file with 91 additions and 86 deletions.
177 changes: 91 additions & 86 deletions lfs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -677,15 +677,14 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
return 0;
}

static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
lfs_entry_t *entry, struct lfs_region *regions) {
static int lfs_dir_append_(lfs_t *lfs, lfs_dir_t *dir,
lfs_off_t *off, lfs_size_t size, struct lfs_region *regions) {
// check if we fit, if top bit is set we do not and move on
while (true) {
if ((0x7fffffff & dir->d.size) + lfs_entry_size(entry)
<= lfs->cfg->block_size) {
entry->off = dir->d.size - 4;
if ((0x7fffffff & dir->d.size) + size <= lfs->cfg->block_size) {
*off = dir->d.size - 4;
for (struct lfs_region *r = regions; r; r = r->next) {
r->off += entry->off;
r->off += *off;
}

return lfs_dir_commit(lfs, dir, regions);
Expand All @@ -701,9 +700,9 @@ static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,

dir->d.tail[0] = olddir.d.tail[0];
dir->d.tail[1] = olddir.d.tail[1];
entry->off = dir->d.size - 4;
*off = dir->d.size - 4;
for (struct lfs_region *r = regions; r; r = r->next) {
r->off += entry->off;
r->off += *off;
}

err = lfs_dir_commit(lfs, dir, regions);
Expand All @@ -724,9 +723,70 @@ static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
}
}

static int lfs_dir_remove_(lfs_t *lfs, lfs_dir_t *dir,
lfs_off_t off, lfs_size_t size) {
// check if we should just drop the directory block
if ((dir->d.size & 0x7fffffff) == sizeof(dir->d)+4 + size) {
lfs_dir_t pdir;
int res = lfs_pred(lfs, dir->pair, &pdir);
if (res < 0) {
return res;
}

if (pdir.d.size & 0x80000000) {
pdir.d.size &= dir->d.size | 0x7fffffff;
pdir.d.tail[0] = dir->d.tail[0];
pdir.d.tail[1] = dir->d.tail[1];
return lfs_dir_commit(lfs, &pdir, NULL);
}
}

// shift out the entry
int err = lfs_dir_commit(lfs, dir,
&(struct lfs_region){
off, -size,
lfs_commit_mem, NULL, 0});
if (err) {
return err;
}

// shift over any files/directories that are affected
for (lfs_file_t *f = lfs->files; f; f = f->next) {
if (lfs_paircmp(f->pair, dir->pair) == 0) {
if (f->poff == off) {
f->pair[0] = 0xffffffff;
f->pair[1] = 0xffffffff;
} else if (f->poff > off) {
f->poff -= size;
}
}
}

for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
if (lfs_paircmp(d->pair, dir->pair) == 0) {
if (d->off > off) {
d->off -= size;
d->pos -= size;
}
}
}

return 0;
}

static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
lfs_entry_t *entry, struct lfs_region *regions) {
return lfs_dir_append_(lfs, dir,
&entry->off, lfs_entry_size(entry), regions);
}

static int lfs_dir_remove(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
return lfs_dir_remove_(lfs, dir,
entry->off, lfs_entry_size(entry));
}

static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
lfs_entry_t *entry, struct lfs_region *regions) {
lfs_off_t oldoff = entry->off; // <- TODO rm me?
lfs_ssize_t diff = 0;
for (struct lfs_region *r = regions; r; r = r->next) {
diff += r->diff;
Expand All @@ -742,6 +802,24 @@ static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
if (err) {
return err;
}

// shift over any files/directories that are affected
for (lfs_file_t *f = lfs->files; f; f = f->next) {
if (lfs_paircmp(f->pair, dir->pair) == 0) {
if (f->poff > entry->off) {
f->poff += diff;
}
}
}

for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
if (lfs_paircmp(d->pair, dir->pair) == 0) {
if (d->off > entry->off) {
d->off += diff;
d->pos += diff;
}
}
}
} else {
lfs_dir_t olddir = *dir;
lfs_off_t oldoff = entry->off;
Expand All @@ -756,9 +834,9 @@ static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
if (err) {
return err;
}
entry->d.type &= LFS_STRUCT_MOVED;

// append updated entry
entry->d.type &= LFS_STRUCT_MOVED;
err = lfs_dir_append(lfs, dir, entry,
&(struct lfs_region){
0, +lfs_entry_size(entry),
Expand All @@ -769,86 +847,13 @@ static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
}

// remove old entry
err = lfs_dir_commit(lfs, &olddir,
&(struct lfs_region){
oldoff, -oldsize,
lfs_commit_mem, NULL, 0});
err = lfs_dir_remove_(lfs, dir, oldoff, oldsize);
if (err) {
return err;
}
}

// TODO move to dir_commit?
// TODO this doesn't work...
// shift over any files/directories that are affected
for (lfs_file_t *f = lfs->files; f; f = f->next) {
if (lfs_paircmp(f->pair, dir->pair) == 0) {
if (f->poff == oldoff) {
f->poff = entry->off;
} else if (f->poff > entry->off) {
f->poff += diff;
}
}
}

for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
if (lfs_paircmp(d->pair, dir->pair) == 0) {
if (d->off > entry->off) {
d->off += diff;
d->pos += diff;
}
}
}

return 0;
}

static int lfs_dir_remove(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
// check if we should just drop the directory block
if ((dir->d.size & 0x7fffffff) == sizeof(dir->d)+4
+ lfs_entry_size(entry)) {
lfs_dir_t pdir;
int res = lfs_pred(lfs, dir->pair, &pdir);
if (res < 0) {
return res;
}

if (pdir.d.size & 0x80000000) {
pdir.d.size &= dir->d.size | 0x7fffffff;
pdir.d.tail[0] = dir->d.tail[0];
pdir.d.tail[1] = dir->d.tail[1];
return lfs_dir_commit(lfs, &pdir, NULL);
}
}

// shift out the entry
int err = lfs_dir_commit(lfs, dir,
&(struct lfs_region){
entry->off, -lfs_entry_size(entry),
lfs_commit_mem, NULL, 0});
if (err) {
return err;
}

// shift over any files/directories that are affected
for (lfs_file_t *f = lfs->files; f; f = f->next) {
if (lfs_paircmp(f->pair, dir->pair) == 0) {
if (f->poff == entry->off) {
f->pair[0] = 0xffffffff;
f->pair[1] = 0xffffffff;
} else if (f->poff > entry->off) {
f->poff -= lfs_entry_size(entry);
}
}
}

for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
if (lfs_paircmp(d->pair, dir->pair) == 0) {
if (d->off > entry->off) {
d->off -= lfs_entry_size(entry);
d->pos -= lfs_entry_size(entry);
}
}
// TODO remove file under file?
// TODO need to shift entries?
}

return 0;
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