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Deduplicated shrub updates into lfsr_file_carveinlined

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lfsr_file_carveinlined writes data into a shrub, while handling both the
carving logic of data we might be overlapping, and any hole logic we
need to fill out the tree.

This provides a nice, relatively simple but flexible, operation for all
shrub updates:

  static int lfsr_file_carveinlined(lfs_t *lfs, lfsr_file_t *file,
          lfs_off_t pos, lfs_off_t weight, lfs_soff_t delta,
          lfsr_data_t data);

I'm quite happy with how these internal carveinlined/carvebtree
functions are coming together. It's nice to have all of that logic in
one place, even if it's a bit complex.
This commit is contained in:
Christopher Haster
2023-10-07 16:15:42 -05:00
parent 39f417db45
commit aa64c85317
1 changed files with 79 additions and 421 deletions
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lfs.c
+52 -394
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@@ -9195,7 +9195,7 @@ lfs_ssize_t lfsr_file_read(lfs_t *lfs, lfsr_file_t *file,
// TODO deduplicate carveshrub and flushinlined // TODO deduplicate carveshrub and flushinlined
// TODO buildcarveshrub? // TODO buildcarveshrub?
static int lfsr_file_carveshrub(lfs_t *lfs, lfsr_file_t *file, static int lfsr_file_carveinlined(lfs_t *lfs, lfsr_file_t *file,
lfs_off_t pos, lfs_off_t weight, lfs_soff_t delta, lfs_off_t pos, lfs_off_t weight, lfs_soff_t delta,
lfsr_data_t data) { lfsr_data_t data) {
// we should never try to shove more data into less weight // we should never try to shove more data into less weight
@@ -9229,10 +9229,12 @@ static int lfsr_file_carveshrub(lfs_t *lfs, lfsr_file_t *file,
} }
// append our data // append our data
if (weight + delta > 0) {
*attrs_++ = LFSR_ATTR(pos, *attrs_++ = LFSR_ATTR(pos,
SHRUB(INLINED), +weight + delta, DATA(data)); SHRUB(INLINED), +weight + delta, DATA(data));
estimate += LFSR_ATTR_ESTIMATE estimate += LFSR_ATTR_ESTIMATE
+ lfsr_data_size(&data); + lfsr_data_size(&data);
}
// right data? // right data?
if (lfsr_data_size(&file->inlined.u.data) > pos + weight) { if (lfsr_data_size(&file->inlined.u.data) > pos + weight) {
@@ -9345,6 +9347,7 @@ static int lfsr_file_carveshrub(lfs_t *lfs, lfsr_file_t *file,
lfs_off_t rm = lfs_min32( lfs_off_t rm = lfs_min32(
pos + weight + right_weight - left_overlap, pos + weight + right_weight - left_overlap,
file->inlined.u.rbyd.weight - left_overlap) - pos; file->inlined.u.rbyd.weight - left_overlap) - pos;
if (rm > 0) {
*attrs_++ = LFSR_ATTR(pos + rm - 1, SHRUB(RM), -rm, NULL); *attrs_++ = LFSR_ATTR(pos + rm - 1, SHRUB(RM), -rm, NULL);
// updating our estimate gets a bit tricky here // updating our estimate gets a bit tricky here
@@ -9357,19 +9360,27 @@ static int lfsr_file_carveshrub(lfs_t *lfs, lfsr_file_t *file,
return rm_estimate; return rm_estimate;
} }
estimate -= rm_estimate; estimate -= rm_estimate;
}
// TODO there's probably a way to restructure this that makes more
// sense...
if (lfsr_data_size(&right_data) == 0) { if (lfsr_data_size(&right_data) == 0) {
// append our buffer with any remaining weight // append our buffer with any remaining weight
if (weight + delta + right_weight > 0) {
*attrs_++ = LFSR_ATTR(pos, *attrs_++ = LFSR_ATTR(pos,
SHRUB(INLINED), +weight + delta + right_weight, DATA(data)); SHRUB(INLINED), +weight + delta + right_weight,
DATA(data));
estimate += LFSR_ATTR_ESTIMATE estimate += LFSR_ATTR_ESTIMATE
+ lfsr_data_size(&data); + lfsr_data_size(&data);
}
} else { } else {
// append our buffer // append our buffer
if (weight + delta > 0) {
*attrs_++ = LFSR_ATTR(pos, *attrs_++ = LFSR_ATTR(pos,
SHRUB(INLINED), +weight + delta, DATA(data)); SHRUB(INLINED), +weight + delta, DATA(data));
estimate += LFSR_ATTR_ESTIMATE estimate += LFSR_ATTR_ESTIMATE
+ lfsr_data_size(&data); + lfsr_data_size(&data);
}
// and any right data // and any right data
*attrs_++ = LFSR_ATTR(pos + weight + delta, *attrs_++ = LFSR_ATTR(pos + weight + delta,
SHRUB(INLINED), +right_weight, DATA(right_data)); SHRUB(INLINED), +right_weight, DATA(right_data));
@@ -9378,23 +9389,24 @@ static int lfsr_file_carveshrub(lfs_t *lfs, lfsr_file_t *file,
} }
} }
// TODO can this happen? should we even have special handling here?
// this is a noop?
if (attrs_ == scratch_attrs) {
return 0;
}
// TODO // TODO
// we can't let our inline shrub overflow our inline size, so if our // we can't let our inline shrub overflow our inline size, so if our
// estimate overflows, we need to flush inlined data // estimate overflows, we need to flush inlined data
// printf("estimate: %d -> %d (%+d)\n",
// (!lfsr_file_hasshrub(file)
// ? 0
// : file->inlined.u.shrub.estimate),
// estimate,
// estimate - (!lfsr_file_hasshrub(file)
// ? 0
// : file->inlined.u.shrub.estimate));
LFS_ASSERT((lfs_soff_t)estimate >= 0); LFS_ASSERT((lfs_soff_t)estimate >= 0);
// TODO can truncate/fruncate trigger this? say fruncate creates a hole,
// should carveinlined just call flushinlined if we overflow?
if (estimate > lfs->cfg->inline_size) { if (estimate > lfs->cfg->inline_size) {
return LFS_ERR_RANGE; //return LFS_ERR_RANGE;
} }
// commit our attributes // commit our attributes
// TODO can we ever end up with no attrs here?
int err = lfsr_mdir_commit(lfs, &file->m.mdir, LFSR_ATTRS( int err = lfsr_mdir_commit(lfs, &file->m.mdir, LFSR_ATTRS(
LFSR_ATTR_(file->m.mdir.mid, SHRUBATTRS, 0, SHRUBATTRS(file, LFSR_ATTR_(file->m.mdir.mid, SHRUBATTRS, 0, SHRUBATTRS(file,
scratch_attrs, scratch_attrs,
@@ -9624,8 +9636,7 @@ static int lfsr_file_carvebtree(lfs_t *lfs, lfsr_file_t *file,
return 0; return 0;
} }
static int lfsr_file_flushinlined(lfs_t *lfs, lfsr_file_t *file, static int lfsr_file_flushinlined(lfs_t *lfs, lfsr_file_t *file) {
lfs_off_t overflow) {
// TODO should we aim for overflow? // TODO should we aim for overflow?
// while (overflow > 0) { // while (overflow > 0) {
// TODO is there some way to deduplicate this "read" loop? seems // TODO is there some way to deduplicate this "read" loop? seems
@@ -10042,7 +10053,7 @@ static int lfsr_file_flushinlined(lfs_t *lfs, lfsr_file_t *file,
// note this clears any data from 0, we should never have data < pos // note this clears any data from 0, we should never have data < pos
// in our current flushinlined implementation and this coalesces any // in our current flushinlined implementation and this coalesces any
// holes together // holes together
err = lfsr_file_carveshrub(lfs, file, 0, pos_ + size_, 0, err = lfsr_file_carveinlined(lfs, file, 0, pos_ + size_, 0,
LFSR_DATA_NULL); LFSR_DATA_NULL);
if (err) { if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE); LFS_ASSERT(err != LFS_ERR_RANGE);
@@ -10070,231 +10081,28 @@ static int lfsr_file_flushinlined(lfs_t *lfs, lfsr_file_t *file,
} }
static int lfsr_file_flushbuffer(lfs_t *lfs, lfsr_file_t *file) { static int lfsr_file_flushbuffer(lfs_t *lfs, lfsr_file_t *file) {
// TODO restructure this based on how flushinlined interacts with
// our buffer?
while (file->buffer_size > 0) { while (file->buffer_size > 0) {
// build up attributes that flush our buffer, at this point // try to flush our buffer into our shrub
// this has basically turned into a tiny compiler int err = lfsr_file_carveinlined(lfs, file,
lfsr_attr_t scratch_attrs[4]; file->buffer_pos, file->buffer_size, 0,
lfsr_attr_t *attrs_ = scratch_attrs; LFSR_DATA_BUF(file->buffer, file->buffer_size));
// keep track of how our changes affect our estimate
lfs_off_t estimate;
// have a sprout/null?
if (!lfsr_file_hasshrub(file)) {
estimate = 0;
// left data? this may create a hole
if (file->buffer_pos > 0) {
*attrs_++ = LFSR_ATTR(0,
SHRUB(INLINED), +file->buffer_pos, DISK(
file->inlined.u.data.u.disk.block,
file->inlined.u.data.u.disk.off,
lfs_min32(
lfsr_data_size(&file->inlined.u.data),
file->buffer_pos)));
estimate += LFSR_ATTR_ESTIMATE
+ lfs_min32(
lfsr_data_size(&file->inlined.u.data),
file->buffer_pos);
}
// append our buffer
*attrs_++ = LFSR_ATTR(file->buffer_pos,
SHRUB(INLINED), +file->buffer_size, BUF(
file->buffer, file->buffer_size));
estimate += LFSR_ATTR_ESTIMATE
+ file->buffer_size;
// right data?
if (lfsr_data_size(&file->inlined.u.data)
> file->buffer_pos + file->buffer_size) {
*attrs_++ = LFSR_ATTR(file->buffer_pos + file->buffer_size,
SHRUB(INLINED), +lfsr_data_size(&file->inlined.u.data)
- (file->buffer_pos + file->buffer_size),
DISK(
file->inlined.u.data.u.disk.block,
file->inlined.u.data.u.disk.off
+ (file->buffer_pos + file->buffer_size),
lfsr_data_size(&file->inlined.u.data)
- (file->buffer_pos + file->buffer_size)));
estimate += LFSR_ATTR_ESTIMATE
+ lfsr_data_size(&file->inlined.u.data)
- (file->buffer_pos + file->buffer_size);
}
// have a shrub?
} else {
// this should never happen, every route to zero-weight shrub
// should revert to an inlined file
LFS_ASSERT(file->inlined.u.rbyd.weight > 0);
estimate = file->inlined.u.shrub.estimate;
// left sibling?
lfs_soff_t left_overlap = 0;
if (file->buffer_pos > 0) {
lfsr_srid_t left_rid;
lfsr_tag_t left_tag;
lfsr_rid_t left_weight;
lfsr_data_t left_data;
int err = lfsr_rbyd_lookupnext(lfs, &file->inlined.u.rbyd,
lfs_min32(
file->buffer_pos,
file->inlined.u.rbyd.weight)-1, 0,
&left_rid, &left_tag, &left_weight, &left_data);
if (err) { if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT); // uh oh, doesn't fit? flush inlined data and try again
return err; if (err == LFS_ERR_RANGE) {
} err = lfsr_file_flushinlined(lfs, file);
LFS_ASSERT(left_tag == LFSR_TAG_SHRUB(INLINED));
LFS_ASSERT(lfsr_data_size(&left_data) <= left_weight);
// this can be negative!
left_overlap = (left_rid+1) - file->buffer_pos;
// can we get away with a simple grow attr? this may
// create a hole
if (left_overlap != 0
&& file->buffer_pos
>= left_rid-(left_weight-1)
+ lfsr_data_size(&left_data)) {
*attrs_++ = LFSR_ATTR(left_rid,
SHRUB(GROW), -left_overlap, NULL);
// need to carve out left data?
} else if (left_overlap > 0) {
*attrs_++ = LFSR_ATTR(left_rid,
SHRUB(GROW(INLINED)), -left_overlap,
DISK(
left_data.u.disk.block,
left_data.u.disk.off,
left_weight - left_overlap));
estimate -= lfsr_data_size(&left_data)
- (left_weight - left_overlap);
}
}
// right sibling?
//
// this gets messy, keep in mind right sibling can be the same
// attr as the left sibling
lfsr_rid_t right_weight = 0;
lfsr_data_t right_data = LFSR_DATA_NULL;
if (file->buffer_pos + file->buffer_size
< (lfs_off_t)file->inlined.u.rbyd.weight) {
lfsr_srid_t right_rid;
lfsr_tag_t right_tag;
lfsr_rid_t right_weight_;
lfsr_data_t right_data_;
int err = lfsr_rbyd_lookupnext(lfs, &file->inlined.u.rbyd,
file->buffer_pos + file->buffer_size, 0,
&right_rid, &right_tag, &right_weight_, &right_data_);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
LFS_ASSERT(right_tag == LFSR_TAG_SHRUB(INLINED));
LFS_ASSERT(lfsr_data_size(&right_data) <= right_weight);
lfs_soff_t right_overlap
= file->buffer_pos + file->buffer_size
- (right_rid-(right_weight_-1));
// need to carve out right data? note we eagerly merge with
// data-less holes
if (right_overlap > 0 || lfsr_data_size(&right_data_) == 0) {
right_data = LFSR_DATA_DISK(
right_data_.u.disk.block,
right_data_.u.disk.off + right_overlap,
lfsr_data_size(&right_data_) - lfs_min32(
right_overlap,
lfsr_data_size(&right_data_)));
right_weight = right_weight_ - right_overlap;
}
}
// remove any data we're overwriting, note we need to account for
// left_sibling changes
lfs_off_t rm = lfs_min32(
file->buffer_pos + file->buffer_size
+ right_weight - left_overlap,
file->inlined.u.rbyd.weight - left_overlap)
- file->buffer_pos;
*attrs_++ = LFSR_ATTR(file->buffer_pos + rm - 1,
SHRUB(RM), -rm, NULL);
// updating our estimate gets a bit tricky here
lfs_ssize_t rm_estimate = lfsr_rbyd_estimate(lfs,
&file->inlined.u.rbyd,
file->buffer_pos + left_overlap,
file->buffer_pos + left_overlap + rm,
NULL);
if (rm_estimate < 0) {
return rm_estimate;
}
estimate -= rm_estimate;
if (lfsr_data_size(&right_data) == 0) {
// append our buffer with any remaining weight
*attrs_++ = LFSR_ATTR(file->buffer_pos,
SHRUB(INLINED), +file->buffer_size + right_weight, BUF(
file->buffer, file->buffer_size));
estimate += LFSR_ATTR_ESTIMATE
+ file->buffer_size;
} else {
// append our buffer
*attrs_++ = LFSR_ATTR(file->buffer_pos,
SHRUB(INLINED), +file->buffer_size, BUF(
file->buffer, file->buffer_size));
estimate += LFSR_ATTR_ESTIMATE
+ file->buffer_size;
// and any right data
*attrs_++ = LFSR_ATTR(file->buffer_pos + file->buffer_size,
SHRUB(INLINED), +right_weight, DATA(right_data));
estimate += LFSR_ATTR_ESTIMATE
+ lfsr_data_size(&right_data);
}
}
// TODO
// we can't let our inline shrub overflow our inline size, so if our
// estimate overflows, we need to flush inlined data
// printf("estimate: %d -> %d (%+d)\n",
// (!lfsr_file_hasshrub(file)
// ? 0
// : file->inlined.u.shrub.estimate),
// estimate,
// estimate - (!lfsr_file_hasshrub(file)
// ? 0
// : file->inlined.u.shrub.estimate));
LFS_ASSERT((lfs_soff_t)estimate >= 0);
if (estimate > lfs->cfg->inline_size) {
int err = lfsr_file_flushinlined(lfs, file,
estimate - lfs->cfg->inline_size);
if (err) { if (err) {
return err; return err;
} }
continue; continue;
} }
// commit our attributes
int err = lfsr_mdir_commit(lfs, &file->m.mdir, LFSR_ATTRS(
LFSR_ATTR_(file->m.mdir.mid, SHRUBATTRS, 0, SHRUBATTRS(file,
scratch_attrs,
attrs_ - scratch_attrs))));
if (err) {
return err; return err;
} }
// update estimate
file->inlined.u.shrub.estimate = estimate;
// we've flushed our buffer // we've flushed our buffer
file->buffer_size = 0; file->buffer_size = 0;
continue;
// TODO check overhead?
} }
return 0; return 0;
@@ -10527,9 +10335,6 @@ int lfsr_file_truncate(lfs_t *lfs, lfsr_file_t *file, lfs_off_t size) {
// mark as unsynced before we commit anything // mark as unsynced before we commit anything
file->flags |= LFS_F_UNSYNCED; file->flags |= LFS_F_UNSYNCED;
lfsr_attr_t scratch_attrs[2];
lfsr_attr_t *attrs_ = scratch_attrs;
// if our truncated file is contained entirely in our buffer, // if our truncated file is contained entirely in our buffer,
// revert to a sprout // revert to a sprout
lfs_size_t buffer_size = lfs_min32( lfs_size_t buffer_size = lfs_min32(
@@ -10538,84 +10343,22 @@ int lfsr_file_truncate(lfs_t *lfs, lfsr_file_t *file, lfs_off_t size) {
if (buffer_size >= size) { if (buffer_size >= size) {
file->inlined.u.data = LFSR_DATA_DISK(0, 0, 0); file->inlined.u.data = LFSR_DATA_DISK(0, 0, 0);
// have a sprout/null? convert to a shrub // TODO, wait, could we just update file->size and leave it to
} else if (!lfsr_file_hasshrub(file)) { // lfsr_file_sync to update the shrub?
*attrs_++ = LFSR_ATTR(0, // otherwise, we need to modify our sprout/shrub
SHRUB(INLINED), +size, DISK( } else {
file->inlined.u.data.u.disk.block, int err = lfsr_file_carveinlined(lfs, file,
file->inlined.u.data.u.disk.off, lfs_min32(file->size, size),
lfs_min32( file->size - lfs_min32(file->size, size),
lfsr_data_size(&file->inlined.u.data), +size - file->size,
size))); LFSR_DATA_NULL);
// have a shrub?
} else if (lfsr_file_hasshrub(file)) {
// TODO can this be deduplicated with flushbuffer? some sort of
// lfsr_file_shrubcarveleft?
// this should never happen, every route to zero-weight shrub
// should revert to an inlined file
LFS_ASSERT(file->inlined.u.rbyd.weight > 0);
// left sibling?
lfs_soff_t left_overlap = 0;
lfsr_srid_t left_rid;
lfsr_tag_t left_tag;
lfsr_rid_t left_weight;
lfsr_data_t left_data;
int err = lfsr_rbyd_lookupnext(lfs, &file->inlined.u.rbyd,
lfs_min32(
size,
file->inlined.u.rbyd.weight)-1, 0,
&left_rid, &left_tag, &left_weight, &left_data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
LFS_ASSERT(left_tag == LFSR_TAG_SHRUB(INLINED));
LFS_ASSERT(lfsr_data_size(&left_data) <= left_weight);
// this can be negative!
left_overlap = (left_rid+1) - size;
// can we get away with a simple grow attr? this may
// create a hole
if (left_overlap != 0
&& size
>= left_rid-(left_weight-1)
+ lfsr_data_size(&left_data)) {
*attrs_++ = LFSR_ATTR(left_rid,
SHRUB(GROW), -left_overlap, NULL);
// need to carve out left data?
} else if (left_overlap > 0) {
*attrs_++ = LFSR_ATTR(left_rid,
SHRUB(GROW(INLINED)), -left_overlap,
DISK(
left_data.u.disk.block,
left_data.u.disk.off,
left_weight - left_overlap));
}
// remove any data we're truncating
*attrs_++ = LFSR_ATTR(file->inlined.u.rbyd.weight
- left_overlap - 1,
SHRUB(RM), -(file->inlined.u.rbyd.weight
- size - left_overlap), NULL);
}
// commit any shrub changes
if (attrs_ > scratch_attrs) {
int err = lfsr_mdir_commit(lfs, &file->m.mdir, LFSR_ATTRS(
LFSR_ATTR_(file->m.mdir.mid, SHRUBATTRS, 0, SHRUBATTRS(file,
scratch_attrs,
attrs_ - scratch_attrs))));
if (err) { if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err; return err;
} }
} }
// TODO update btree // TODO update btree?
// update our buffer // update our buffer
file->buffer_size = buffer_size; file->buffer_size = buffer_size;
@@ -10642,9 +10385,6 @@ int lfsr_file_fruncate(lfs_t *lfs, lfsr_file_t *file, lfs_off_t size) {
// mark as unsynced before we commit anything // mark as unsynced before we commit anything
file->flags |= LFS_F_UNSYNCED; file->flags |= LFS_F_UNSYNCED;
lfsr_attr_t scratch_attrs[2];
lfsr_attr_t *attrs_ = scratch_attrs;
// if our truncated file is contained entirely in our buffer, // if our truncated file is contained entirely in our buffer,
// revert to a sprout // revert to a sprout
lfs_size_t buffer_size = file->buffer_size - lfs_min32( lfs_size_t buffer_size = file->buffer_size - lfs_min32(
@@ -10654,95 +10394,13 @@ int lfsr_file_fruncate(lfs_t *lfs, lfsr_file_t *file, lfs_off_t size) {
&& file->size - size >= lfsr_file_inlinedsize(file)) { && file->size - size >= lfsr_file_inlinedsize(file)) {
file->inlined.u.data = LFSR_DATA_DISK(0, 0, 0); file->inlined.u.data = LFSR_DATA_DISK(0, 0, 0);
// have a sprout/null? convert to a shrub // otherwise, we need to modify our sprout/shrub and btree
} else if (!lfsr_file_hasshrub(file)) { } else {
if (lfsr_data_size(&file->inlined.u.data) != 0) { int err = lfsr_file_carveinlined(lfs, file,
*attrs_++ = LFSR_ATTR(0, 0,
SHRUB(INLINED), +lfsr_data_size(&file->inlined.u.data) lfs_smax32(file->size - size, 0),
- lfs_smax32(file->size - size, 0), +size - file->size,
DISK( LFSR_DATA_NULL);
file->inlined.u.data.u.disk.block,
file->inlined.u.data.u.disk.off
+ lfs_smax32(file->size - size, 0),
lfsr_data_size(&file->inlined.u.data)
- lfs_smax32(file->size - size, 0)));
}
// need to prefix with a hole?
if (size > file->size) {
*attrs_++ = LFSR_ATTR(0,
SHRUB(INLINED), +size - file->size, NULL);
}
// have a shrub?
} else if (lfsr_file_hasshrub(file)) {
// TODO can this be deduplicated with flushbuffer? some sort of
// lfsr_file_shrubcarveright?
// this should never happen, every route to zero-weight shrub
// should revert to an inlined file
LFS_ASSERT(file->inlined.u.rbyd.weight > 0);
// TODO wait a second... are we always copying right sibling in
// flushbuffer? even with no carve?
// right sibling?
lfsr_rid_t right_weight = 0;
lfsr_data_t right_data = LFSR_DATA_NULL;
if (lfs_smax32(file->size - size, 0) < file->inlined.u.rbyd.weight) {
lfsr_srid_t right_rid;
lfsr_tag_t right_tag;
lfsr_rid_t right_weight_;
lfsr_data_t right_data_;
int err = lfsr_rbyd_lookupnext(lfs, &file->inlined.u.rbyd,
lfs_smax32(file->size - size, 0), 0,
&right_rid, &right_tag, &right_weight_, &right_data_);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
LFS_ASSERT(right_tag == LFSR_TAG_SHRUB(INLINED));
LFS_ASSERT(lfsr_data_size(&right_data) <= right_weight);
lfs_soff_t right_overlap
= lfs_smax32(file->size - size, 0)
- (right_rid-(right_weight_-1));
// need to carve out right data? note we eagerly merge with
// data-less holes
if (right_overlap > 0 || lfsr_data_size(&right_data_) == 0) {
right_data = LFSR_DATA_DISK(
right_data_.u.disk.block,
right_data_.u.disk.off + right_overlap,
lfsr_data_size(&right_data_) - lfs_min32(
right_overlap,
lfsr_data_size(&right_data_)));
right_weight = right_weight_ - right_overlap;
}
}
// remove any data we're fruncating
*attrs_++ = LFSR_ATTR(lfs_smax32(file->size - size, 0)
+ right_weight - 1,
SHRUB(RM), -(lfs_smax32(file->size - size, 0)
+ right_weight), NULL);
// write any carved data or a hole, note we take care to consume any
// existing data-less holes to avoid fragmenting literally nothing
if (lfs_smax32(size - file->size, 0) + right_weight > 0) {
*attrs_++ = LFSR_ATTR(0,
SHRUB(INLINED), +lfs_smax32(size - file->size, 0)
+ right_weight,
DATA(right_data));
}
}
// commit any shrub changes
if (attrs_ > scratch_attrs) {
int err = lfsr_mdir_commit(lfs, &file->m.mdir, LFSR_ATTRS(
LFSR_ATTR_(file->m.mdir.mid, SHRUBATTRS, 0, SHRUBATTRS(file,
scratch_attrs,
attrs_ - scratch_attrs))));
if (err) { if (err) {
return err; return err;
} }