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-rw-r--r--src/shared/btrfs-util.c127
1 files changed, 95 insertions, 32 deletions
diff --git a/src/shared/btrfs-util.c b/src/shared/btrfs-util.c
index e648121b47..bd100eef0b 100644
--- a/src/shared/btrfs-util.c
+++ b/src/shared/btrfs-util.c
@@ -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;
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2025-10-25 11:33:24 +0000