libfdisk: support resize operation in fdisk_set_partition()
Note that the resize is not exported by API yet, the only way to use it is sfdisk-like scripts. Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak
parent
b17c1f1447
commit
98e15beb61
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@ -70,6 +70,24 @@ void fdisk_reset_partition(struct fdisk_partition *pa)
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init_partition(pa);
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}
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static struct fdisk_partition *__copy_partition(struct fdisk_partition *o)
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{
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struct fdisk_partition *n = fdisk_new_partition();
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if (!n)
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return NULL;
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memcpy(n, o, sizeof(*n));
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if (n->type)
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fdisk_ref_parttype(n->type);
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if (o->name)
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n->name = strdup(o->name);
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if (o->uuid)
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n->uuid = strdup(o->uuid);
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if (o->attrs)
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n->attrs = strdup(o->attrs);
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return n;
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}
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/**
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* fdisk_ref_partition:
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* @pa: partition pointer
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@ -224,7 +242,6 @@ int fdisk_partition_start_is_default(struct fdisk_partition *pa)
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return pa->start_follow_default;
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}
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/**
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* fdisk_partition_set_size:
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* @pa: partition
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@ -507,8 +524,8 @@ fdisk_sector_t fdisk_partition_get_end(struct fdisk_partition *pa)
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* @pa: partition
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* @enable: 0|1
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*
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* When @pa used as a template for fdisk_add_partition() when force label driver
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* to use all the possible space for the new partition.
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* When @pa used as a template for fdisk_add_partition() when force label
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* driver to use all the possible space for the new partition.
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*
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* Returns: 0 on success, <0 on error.
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*/
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@ -904,6 +921,186 @@ int fdisk_get_partition(struct fdisk_context *cxt, size_t partno,
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return rc;
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}
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static struct fdisk_partition *resize_get_by_offset(
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struct fdisk_table *tb, fdisk_sector_t off)
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{
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struct fdisk_partition *pa = NULL;
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struct fdisk_iter itr;
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fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
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while (fdisk_table_next_partition(tb, &itr, &pa) == 0) {
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if (!fdisk_partition_has_start(pa) || !fdisk_partition_has_size(pa))
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continue;
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if (off >= pa->start && off < pa->start + pa->size)
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return pa;
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}
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return NULL;
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}
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/*
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* Verify that area addressed by @start is freespace or the @cur[rent]
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* partition and continue to the next table entries until it's freespace, and
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* counts size of all this space.
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*
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* This is core of the partition start offset move operation. We can move the
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* start within the current partition of to the another free space. It's
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* forbidden to move start of the partition to another already defined
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* partition.
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*/
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static int resize_get_last_possible(
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struct fdisk_table *tb,
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struct fdisk_partition *cur,
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fdisk_sector_t start,
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fdisk_sector_t *maxsz)
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{
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struct fdisk_partition *pa = NULL, *last = NULL;
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struct fdisk_iter itr;
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fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
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*maxsz = 0;
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while (fdisk_table_next_partition(tb, &itr, &pa) == 0) {
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if (!fdisk_partition_has_start(pa) ||
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!fdisk_partition_has_size(pa) ||
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fdisk_partition_is_container(pa))
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continue;
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if (!last) {
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if (start >= pa->start && start < pa->start + pa->size) {
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if (fdisk_partition_is_freespace(pa) || pa == cur)
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last = pa;
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else
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break;
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*maxsz = pa->size - (pa->start - start);
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}
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} else if (!fdisk_partition_is_freespace(pa) && pa != cur) {
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break;
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} else {
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last = pa;
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*maxsz += pa->size;
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}
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}
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if (last)
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DBG(PART, ul_debugobj(cur, "resize: max size=%ju", (uintmax_t) *maxsz));
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return last ? 0 : -1;
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}
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/*
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* Uses template @tpl to recount start and size change of the partition @res. The
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* @tpl->size and @tpl->start are interpreted as relative to the current setting.
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*/
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static int recount_resize(
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struct fdisk_context *cxt, size_t partno,
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struct fdisk_partition *res, struct fdisk_partition *tpl)
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{
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fdisk_sector_t start, size;
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struct fdisk_partition *cur = NULL;
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struct fdisk_table *tb = NULL;
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int rc;
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DBG(PART, ul_debugobj(tpl, "resize requested"));
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FDISK_INIT_UNDEF(start);
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FDISK_INIT_UNDEF(size);
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rc = fdisk_get_partitions(cxt, &tb);
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if (!rc)
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rc = fdisk_get_freespaces(cxt, &tb);
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if (rc)
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return rc;
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cur = fdisk_table_get_partition_by_partno(tb, partno);
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if (!cur) {
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fdisk_unref_table(tb);
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return -EINVAL;
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}
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/* 1a) set new start - change relative to the current on-disk setting */
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if (tpl->movestart && fdisk_partition_has_start(tpl)) {
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start = fdisk_partition_get_start(cur);
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if (tpl->movestart == FDISK_MOVE_DOWN) {
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if (fdisk_partition_get_start(tpl) > start)
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goto erange;
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start -= fdisk_partition_get_start(tpl);
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} else
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start += fdisk_partition_get_start(tpl);
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/* 1b) set new start - absolute number */
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} else if (fdisk_partition_has_start(tpl))
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start = fdisk_partition_get_start(tpl);
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/* 2) verify that start is within the current partition or any freespace area */
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if (!FDISK_IS_UNDEF(start)) {
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struct fdisk_partition *area = resize_get_by_offset(tb, start);
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if (!area)
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goto erange;
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if (area == cur)
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DBG(PART, ul_debugobj(tpl, "resize: start points to the current partition"));
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else if (fdisk_partition_is_freespace(area))
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DBG(PART, ul_debugobj(tpl, "resize: start points to freespace"));
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else
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goto erange;
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} else {
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/* no change, start points to the current partition */
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start = fdisk_partition_get_start(cur);
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}
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/* 3a) set new size -- reduce */
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if (tpl->resize == FDISK_RESIZE_REDUCE && fdisk_partition_has_size(tpl)) {
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DBG(PART, ul_debugobj(tpl, "resize: reduce"));
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size = fdisk_partition_get_size(cur);
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if (fdisk_partition_get_size(tpl) > size)
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goto erange;
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size -= fdisk_partition_get_size(tpl);
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/* 3b) set new size -- enlarge */
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} else if (tpl->resize == FDISK_RESIZE_ENLARGE && fdisk_partition_has_size(tpl)) {
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DBG(PART, ul_debugobj(tpl, "resize: enlarge"));
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size = fdisk_partition_get_size(cur);
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size += fdisk_partition_get_size(tpl);
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/* 3c) set new size -- no size specified, enlarge to all freespace */
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} else if (tpl->resize == FDISK_RESIZE_ENLARGE) {
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DBG(PART, ul_debugobj(tpl, "resize: enlarge to all possible"));
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if (resize_get_last_possible(tb, cur, start, &size))
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goto erange;
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/* 3d) set new size -- absolute number */
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} else if (fdisk_partition_has_size(tpl)) {
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DBG(PART, ul_debugobj(tpl, "resize: new absolute size"));
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size = fdisk_partition_get_size(tpl);
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}
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/* 4) verify that size is within the current partition or next free space */
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if (!FDISK_IS_UNDEF(size)) {
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fdisk_sector_t maxsz;
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if (resize_get_last_possible(tb, cur, start, &maxsz))
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goto erange;
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DBG(PART, ul_debugobj(tpl, "resize: size wanted=%ju, max=%ju",
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(uintmax_t) size, (uintmax_t) maxsz));
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if (size > maxsz)
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goto erange;
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}
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DBG(PART, ul_debugobj(tpl, "resize: SUCCESS: start %ju->%ju; size %ju->%ju",
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(uintmax_t) fdisk_partition_get_start(cur), (uintmax_t) start,
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(uintmax_t) fdisk_partition_get_size(cur), (uintmax_t) size));
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res->start = start;
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res->size = size;
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fdisk_unref_table(tb);
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return 0;
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erange:
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DBG(PART, ul_debugobj(tpl, "resize: FAILED"));
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fdisk_unref_table(tb);
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return -ERANGE;
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}
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/**
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* fdisk_set_partition:
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* @cxt: context
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@ -917,24 +1114,40 @@ int fdisk_get_partition(struct fdisk_context *cxt, size_t partno,
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int fdisk_set_partition(struct fdisk_context *cxt, size_t partno,
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struct fdisk_partition *pa)
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{
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struct fdisk_partition *xpa = pa;
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int rc;
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if (!cxt || !cxt->label || !pa)
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return -EINVAL;
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if (!cxt->label->op->set_part)
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return -ENOSYS;
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DBG(CXT, ul_debugobj(cxt, "setting partition %zu %p (start=%ju, end=%ju, size=%ju, "
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"defaults(start=%s, end=%s, partno=%s)",
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partno, pa,
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(uintmax_t) fdisk_partition_get_start(pa),
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(uintmax_t) fdisk_partition_get_end(pa),
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(uintmax_t) fdisk_partition_get_size(pa),
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pa->start_follow_default ? "yes" : "no",
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pa->end_follow_default ? "yes" : "no",
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pa->partno_follow_default ? "yes" : "no"));
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if (pa->resize || fdisk_partition_has_start(pa) || fdisk_partition_has_size(pa)) {
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xpa = __copy_partition(pa);
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xpa->movestart = 0;
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xpa->resize = 0;
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FDISK_INIT_UNDEF(xpa->size);
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FDISK_INIT_UNDEF(xpa->start);
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return cxt->label->op->set_part(cxt, partno, pa);
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rc = recount_resize(cxt, partno, xpa, pa);
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if (rc)
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goto done;
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}
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DBG(CXT, ul_debugobj(cxt, "setting partition %zu %p (start=%ju, end=%ju, size=%ju)",
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partno, xpa,
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(uintmax_t) fdisk_partition_get_start(xpa),
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(uintmax_t) fdisk_partition_get_end(xpa),
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(uintmax_t) fdisk_partition_get_size(xpa)));
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rc = cxt->label->op->set_part(cxt, partno, xpa);
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done:
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if (xpa != pa)
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fdisk_unref_partition(xpa);
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return rc;
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}
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/**
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* fdisk_add_partition:
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* @cxt: fdisk context
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