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btrfs-util: rework how we iterate through the results of the TREE_SEARCH results

Let's introduce some syntactic sugar with iteration macros, and add
correct key increment calls.
This commit is contained in:
Lennart Poettering 2015-01-07 14:43:10 +01:00
parent b7e7184634
commit 5743a5852d

View File

@ -338,6 +338,77 @@ int btrfs_subvol_get_id_fd(int fd, uint64_t *ret) {
return 0;
}
static bool btrfs_ioctl_search_args_inc(struct btrfs_ioctl_search_args *args) {
assert(args);
/* the objectid, type, offset together make up the btrfs key,
* which is considered a single 136byte integer when
* comparing. This call increases the counter by one, dealing
* with the overflow between the overflows */
if (args->key.min_offset < (uint64_t) -1) {
args->key.min_offset++;
return true;
}
if (args->key.min_type < (uint8_t) -1) {
args->key.min_type++;
args->key.min_offset = 0;
return true;
}
if (args->key.min_objectid < (uint64_t) -1) {
args->key.min_objectid++;
args->key.min_offset = 0;
args->key.min_type = 0;
return true;
}
return 0;
}
static void btrfs_ioctl_search_args_set(struct btrfs_ioctl_search_args *args, const struct btrfs_ioctl_search_header *h) {
assert(args);
assert(h);
args->key.min_objectid = h->objectid;
args->key.min_type = h->type;
args->key.min_offset = h->offset;
}
static int btrfs_ioctl_search_args_compare(const struct btrfs_ioctl_search_args *args) {
assert(args);
/* Compare min and max */
if (args->key.min_objectid < args->key.max_objectid)
return -1;
if (args->key.min_objectid > args->key.max_objectid)
return 1;
if (args->key.min_type < args->key.max_type)
return -1;
if (args->key.min_type > args->key.max_type)
return 1;
if (args->key.min_offset < args->key.max_offset)
return -1;
if (args->key.min_offset > args->key.max_offset)
return 1;
return 0;
}
#define FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) \
for ((i) = 0, \
(sh) = (const struct btrfs_ioctl_search_header*) (args).buf; \
(i) < (args).key.nr_items; \
(i)++, \
(sh) = (const struct btrfs_ioctl_search_header*) ((uint8_t*) (sh) + sizeof(struct btrfs_ioctl_search_header) + (sh)->len))
#define BTRFS_IOCTL_SEARCH_HEADER_BODY(sh) \
((void*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header)))
int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
struct btrfs_ioctl_search_args args = {
/* Tree of tree roots */
@ -347,9 +418,10 @@ int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
.key.min_type = BTRFS_ROOT_ITEM_KEY,
.key.max_type = BTRFS_ROOT_ITEM_KEY,
/* No restrictions on the other components */
.key.min_offset = 0,
.key.max_offset = (uint64_t) -1,
/* No restrictions on the other components */
.key.min_transid = 0,
.key.max_transid = (uint64_t) -1,
};
@ -367,7 +439,7 @@ int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
args.key.min_objectid = args.key.max_objectid = subvol_id;
for (;;) {
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
const struct btrfs_ioctl_search_header *sh;
unsigned i;
@ -378,25 +450,23 @@ int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
if (args.key.nr_items <= 0)
break;
for (i = 0,
sh = (const struct btrfs_ioctl_search_header*) args.buf;
i < args.key.nr_items;
i++,
args.key.min_type = sh->type,
args.key.min_offset = sh->offset,
args.key.min_objectid = sh->objectid,
sh = (const struct btrfs_ioctl_search_header*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header) + sh->len)) {
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
const struct btrfs_root_item *ri;
/* Make sure we start the next search at least from this entry */
btrfs_ioctl_search_args_set(&args, sh);
if (sh->objectid != subvol_id)
continue;
if (sh->type != BTRFS_ROOT_ITEM_KEY)
continue;
/* Older versions of the struct lacked the otime setting */
if (sh->len < offsetof(struct btrfs_root_item, otime) + sizeof(struct btrfs_timespec))
continue;
ri = (const struct btrfs_root_item *)(args.buf + sizeof(struct btrfs_ioctl_search_header));
ri = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
ret->otime = (usec_t) le64toh(ri->otime.sec) * USEC_PER_SEC +
(usec_t) le32toh(ri->otime.nsec) / NSEC_PER_USEC;
@ -412,8 +482,8 @@ int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
goto finish;
}
args.key.min_offset++;
if (!args.key.min_offset) /* overflow */
/* Increase search key by one, to read the next item, if we can. */
if (!btrfs_ioctl_search_args_inc(&args))
break;
}
@ -430,13 +500,14 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
/* Tree of quota items */
.key.tree_id = BTRFS_QUOTA_TREE_OBJECTID,
/* The object ID is always 0 */
.key.min_objectid = 0,
.key.max_objectid = 0,
/* Look precisely for the quota items */
.key.min_type = BTRFS_QGROUP_STATUS_KEY,
.key.max_type = BTRFS_QGROUP_LIMIT_KEY,
.key.min_objectid = 0,
.key.max_objectid = 0,
/* No restrictions on the other components */
.key.min_transid = 0,
.key.max_transid = (uint64_t) -1,
@ -455,7 +526,7 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
args.key.min_offset = args.key.max_offset = subvol_id;
for (;;) {
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
const struct btrfs_ioctl_search_header *sh;
unsigned i;
@ -466,26 +537,18 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
if (args.key.nr_items <= 0)
break;
for (i = 0,
sh = (const struct btrfs_ioctl_search_header*) args.buf;
i < args.key.nr_items;
i++,
args.key.min_type = sh->type,
args.key.min_offset = sh->offset,
args.key.min_objectid = sh->objectid,
sh = (const struct btrfs_ioctl_search_header*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header) + sh->len)) {
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
const void *body;
/* Make sure we start the next search at least from this entry */
btrfs_ioctl_search_args_set(&args, sh);
if (sh->objectid != 0)
continue;
if (sh->offset != subvol_id)
continue;
body = (uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header);
if (sh->type == BTRFS_QGROUP_INFO_KEY) {
const struct btrfs_qgroup_info_item *qii = body;
const struct btrfs_qgroup_info_item *qii = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
ret->referred = le64toh(qii->rfer);
ret->exclusive = le64toh(qii->excl);
@ -493,7 +556,7 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
found_info = true;
} else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) {
const struct btrfs_qgroup_limit_item *qli = body;
const struct btrfs_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
ret->referred_max = le64toh(qli->max_rfer);
ret->exclusive_max = le64toh(qli->max_excl);
@ -510,8 +573,8 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
goto finish;
}
args.key.min_offset++;
if (!args.key.min_offset)
/* Increase search key by one, to read the next item, if we can. */
if (!btrfs_ioctl_search_args_inc(&args))
break;
}