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Revert "libbtrfs: remove the support for fs without uuid tree"

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This reverts commit 83ab92512e.

The commit removed some old code that seemed to be unused but this
actually broke snapper. Revert the changes completely to the v6.3 ABI
level.

Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1212217
Issue: #672
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2023-09-01 12:01:33 +02:00
parent 7a0da24f52
commit f9b0da8e78
2 changed files with 412 additions and 0 deletions
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392
libbtrfs/send-utils.c
View file

@ -199,6 +199,73 @@ static int btrfs_read_root_item(int mnt_fd, u64 root_id,
return 0;
}
#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
static struct rb_node *tree_insert(struct rb_root *root,
struct subvol_info *si,
enum subvol_search_type type)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct subvol_info *entry;
__s64 comp;
while (*p) {
parent = *p;
if (type == subvol_search_by_received_uuid) {
entry = rb_entry(parent, struct subvol_info,
rb_received_node);
comp = memcmp(entry->received_uuid, si->received_uuid,
BTRFS_UUID_SIZE);
if (!comp) {
if (entry->stransid < si->stransid)
comp = -1;
else if (entry->stransid > si->stransid)
comp = 1;
else
comp = 0;
}
} else if (type == subvol_search_by_uuid) {
entry = rb_entry(parent, struct subvol_info,
rb_local_node);
comp = memcmp(entry->uuid, si->uuid, BTRFS_UUID_SIZE);
} else if (type == subvol_search_by_root_id) {
entry = rb_entry(parent, struct subvol_info,
rb_root_id_node);
comp = entry->root_id - si->root_id;
} else if (type == subvol_search_by_path) {
entry = rb_entry(parent, struct subvol_info,
rb_path_node);
comp = strcmp(entry->path, si->path);
} else {
BUG();
}
if (comp < 0)
p = &(*p)->rb_left;
else if (comp > 0)
p = &(*p)->rb_right;
else
return parent;
}
if (type == subvol_search_by_received_uuid) {
rb_link_node(&si->rb_received_node, parent, p);
rb_insert_color(&si->rb_received_node, root);
} else if (type == subvol_search_by_uuid) {
rb_link_node(&si->rb_local_node, parent, p);
rb_insert_color(&si->rb_local_node, root);
} else if (type == subvol_search_by_root_id) {
rb_link_node(&si->rb_root_id_node, parent, p);
rb_insert_color(&si->rb_root_id_node, root);
} else if (type == subvol_search_by_path) {
rb_link_node(&si->rb_path_node, parent, p);
rb_insert_color(&si->rb_path_node, root);
}
return NULL;
}
#endif
int btrfs_subvolid_resolve(int fd, char *path, size_t path_len, u64 subvol_id)
{
if (path_len < 1)
@ -297,6 +364,116 @@ static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
return 0;
}
#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
static int count_bytes(void *buf, int len, char b)
{
int cnt = 0;
int i;
for (i = 0; i < len; i++) {
if (((char *)buf)[i] == b)
cnt++;
}
return cnt;
}
void subvol_uuid_search_add(struct subvol_uuid_search *s,
struct subvol_info *si);
void subvol_uuid_search_add(struct subvol_uuid_search *s,
struct subvol_info *si)
{
int cnt;
tree_insert(&s->root_id_subvols, si, subvol_search_by_root_id);
tree_insert(&s->path_subvols, si, subvol_search_by_path);
cnt = count_bytes(si->uuid, BTRFS_UUID_SIZE, 0);
if (cnt != BTRFS_UUID_SIZE)
tree_insert(&s->local_subvols, si, subvol_search_by_uuid);
cnt = count_bytes(si->received_uuid, BTRFS_UUID_SIZE, 0);
if (cnt != BTRFS_UUID_SIZE)
tree_insert(&s->received_subvols, si,
subvol_search_by_received_uuid);
}
static struct subvol_info *tree_search(struct rb_root *root,
u64 root_id, const u8 *uuid,
u64 stransid, const char *path,
enum subvol_search_type type)
{
struct rb_node *n = root->rb_node;
struct subvol_info *entry;
__s64 comp;
while (n) {
if (type == subvol_search_by_received_uuid) {
entry = rb_entry(n, struct subvol_info,
rb_received_node);
comp = memcmp(entry->received_uuid, uuid,
BTRFS_UUID_SIZE);
if (!comp) {
if (entry->stransid < stransid)
comp = -1;
else if (entry->stransid > stransid)
comp = 1;
else
comp = 0;
}
} else if (type == subvol_search_by_uuid) {
entry = rb_entry(n, struct subvol_info, rb_local_node);
comp = memcmp(entry->uuid, uuid, BTRFS_UUID_SIZE);
} else if (type == subvol_search_by_root_id) {
entry = rb_entry(n, struct subvol_info,
rb_root_id_node);
comp = entry->root_id - root_id;
} else if (type == subvol_search_by_path) {
entry = rb_entry(n, struct subvol_info, rb_path_node);
comp = strcmp(entry->path, path);
} else {
BUG();
}
if (comp < 0)
n = n->rb_left;
else if (comp > 0)
n = n->rb_right;
else
return entry;
}
return NULL;
}
/*
* this function will be only called if kernel doesn't support uuid tree.
*/
static struct subvol_info *subvol_uuid_search_old(struct subvol_uuid_search *s,
u64 root_id, const u8 *uuid, u64 transid,
const char *path,
enum subvol_search_type type)
{
struct rb_root *root;
if (type == subvol_search_by_received_uuid)
root = &s->received_subvols;
else if (type == subvol_search_by_uuid)
root = &s->local_subvols;
else if (type == subvol_search_by_root_id)
root = &s->root_id_subvols;
else if (type == subvol_search_by_path)
root = &s->path_subvols;
else
return NULL;
return tree_search(root, root_id, uuid, transid, path, type);
}
#else
void subvol_uuid_search_add(struct subvol_uuid_search *s,
struct subvol_info *si)
{
if (si) {
free(si->path);
free(si);
}
}
#endif
static struct subvol_info *subvol_uuid_search2(struct subvol_uuid_search *s,
u64 root_id, const u8 *uuid, u64 transid,
const char *path,
@ -394,6 +571,11 @@ static struct subvol_info *subvol_uuid_search2(struct subvol_uuid_search *s,
struct btrfs_root_item root_item;
struct subvol_info *info = NULL;
#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
if (!s->uuid_tree_existed)
return subvol_uuid_search_old(s, root_id, uuid, transid,
path, type);
#endif
switch (type) {
case subvol_search_by_received_uuid:
ret = btrfs_uuid_tree_lookup_any(s->mnt_fd, uuid,
@ -461,9 +643,219 @@ out:
return info;
}
#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
static int is_uuid_tree_supported(int fd)
{
int ret;
struct btrfs_ioctl_search_args args;
struct btrfs_ioctl_search_key *sk = &args.key;
memset(&args, 0, sizeof(args));
sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
sk->min_objectid = BTRFS_UUID_TREE_OBJECTID;
sk->max_objectid = BTRFS_UUID_TREE_OBJECTID;
sk->max_type = BTRFS_ROOT_ITEM_KEY;
sk->min_type = BTRFS_ROOT_ITEM_KEY;
sk->max_offset = (u64)-1;
sk->max_transid = (u64)-1;
sk->nr_items = 1;
ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
if (ret < 0)
return ret;
/* the ioctl returns the number of item it found in nr_items */
if (sk->nr_items == 0)
return 0;
return 1;
}
/*
* this function is mainly used to read all root items
* it will be only used when we use older kernel which uuid
* tree is not supported yet
*/
int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
{
int ret;
struct btrfs_ioctl_search_args args;
struct btrfs_ioctl_search_key *sk = &args.key;
struct btrfs_ioctl_search_header *sh;
struct btrfs_root_item *root_item_ptr;
struct btrfs_root_item root_item = {};
struct subvol_info *si = NULL;
int root_item_valid = 0;
unsigned long off = 0;
int i;
s->mnt_fd = mnt_fd;
s->root_id_subvols = RB_ROOT;
s->local_subvols = RB_ROOT;
s->received_subvols = RB_ROOT;
s->path_subvols = RB_ROOT;
ret = is_uuid_tree_supported(mnt_fd);
if (ret < 0) {
fprintf(stderr,
"ERROR: check if we support uuid tree fails - %m\n");
return ret;
} else if (ret) {
/* uuid tree is supported */
s->uuid_tree_existed = 1;
return 0;
}
memset(&args, 0, sizeof(args));
sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
sk->max_objectid = (u64)-1;
sk->max_offset = (u64)-1;
sk->max_transid = (u64)-1;
sk->min_type = BTRFS_ROOT_ITEM_KEY;
sk->max_type = BTRFS_ROOT_BACKREF_KEY;
sk->nr_items = 4096;
while (1) {
ret = ioctl(mnt_fd, BTRFS_IOC_TREE_SEARCH, &args);
if (ret < 0) {
fprintf(stderr, "ERROR: can't perform the search - %m\n");
return ret;
}
if (sk->nr_items == 0)
break;
off = 0;
for (i = 0; i < sk->nr_items; i++) {
sh = (struct btrfs_ioctl_search_header *)(args.buf +
off);
off += sizeof(*sh);
if ((btrfs_search_header_objectid(sh) != 5 &&
btrfs_search_header_objectid(sh)
< BTRFS_FIRST_FREE_OBJECTID) ||
btrfs_search_header_objectid(sh)
> BTRFS_LAST_FREE_OBJECTID) {
goto skip;
}
if (btrfs_search_header_type(sh)
== BTRFS_ROOT_ITEM_KEY) {
/* older kernels don't have uuids+times */
if (btrfs_search_header_len(sh)
< sizeof(root_item)) {
root_item_valid = 0;
goto skip;
}
root_item_ptr = (struct btrfs_root_item *)
(args.buf + off);
memcpy(&root_item, root_item_ptr,
sizeof(root_item));
root_item_valid = 1;
} else if (btrfs_search_header_type(sh)
== BTRFS_ROOT_BACKREF_KEY ||
root_item_valid) {
char path_buf[PATH_MAX];
char *path;
if (!root_item_valid)
goto skip;
ret = btrfs_subvolid_resolve(mnt_fd, path_buf,
sizeof(path_buf),
btrfs_search_header_objectid(sh));
if (ret < 0) {
errno = -ret;
fprintf(stderr, "ERROR: unable to "
"resolve path "
"for root %llu: %m\n",
btrfs_search_header_objectid(sh));
goto out;
}
path = strdup(path_buf);
si = calloc(1, sizeof(*si));
si->root_id = btrfs_search_header_objectid(sh);
memcpy(si->uuid, root_item.uuid,
BTRFS_UUID_SIZE);
memcpy(si->parent_uuid, root_item.parent_uuid,
BTRFS_UUID_SIZE);
memcpy(si->received_uuid,
root_item.received_uuid,
BTRFS_UUID_SIZE);
si->ctransid = btrfs_root_ctransid(&root_item);
si->otransid = btrfs_root_otransid(&root_item);
si->stransid = btrfs_root_stransid(&root_item);
si->rtransid = btrfs_root_rtransid(&root_item);
si->path = path;
subvol_uuid_search_add(s, si);
root_item_valid = 0;
} else {
goto skip;
}
skip:
off += btrfs_search_header_len(sh);
/*
* record the mins in sk so we can make sure the
* next search doesn't repeat this root
*/
sk->min_objectid = btrfs_search_header_objectid(sh);
sk->min_offset = btrfs_search_header_offset(sh);
sk->min_type = btrfs_search_header_type(sh);
}
sk->nr_items = 4096;
if (sk->min_offset < (u64)-1)
sk->min_offset++;
else if (sk->min_objectid < (u64)-1) {
sk->min_objectid++;
sk->min_offset = 0;
sk->min_type = 0;
} else
break;
}
out:
return ret;
}
void subvol_uuid_search_finit(struct subvol_uuid_search *s);
void subvol_uuid_search_finit(struct subvol_uuid_search *s)
{
struct rb_root *root = &s->root_id_subvols;
struct rb_node *node;
if (!s->uuid_tree_existed)
return;
while ((node = rb_first(root))) {
struct subvol_info *entry =
rb_entry(node, struct subvol_info, rb_root_id_node);
free(entry->path);
rb_erase(node, root);
free(entry);
}
s->root_id_subvols = RB_ROOT;
s->local_subvols = RB_ROOT;
s->received_subvols = RB_ROOT;
s->path_subvols = RB_ROOT;
}
#else
int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
{
s->mnt_fd = mnt_fd;
return 0;
}
void subvol_uuid_search_finit(struct subvol_uuid_search *s)
{
}
#endif

20
libbtrfs/send-utils.h
View file

@ -35,6 +35,12 @@
extern "C" {
#endif
/*
* Compatibility code for kernels < 3.12; the UUID tree is not available there
* and we have to do the slow search. This should be deprecated someday.
*/
#define BTRFS_COMPAT_SEND_NO_UUID_TREE 1
enum subvol_search_type {
subvol_search_by_root_id,
subvol_search_by_uuid,
@ -43,6 +49,12 @@ enum subvol_search_type {
};
struct subvol_info {
#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
struct rb_node rb_root_id_node;
struct rb_node rb_local_node;
struct rb_node rb_received_node;
struct rb_node rb_path_node;
#endif
u64 root_id;
u8 uuid[BTRFS_UUID_SIZE];
@ -58,6 +70,14 @@ struct subvol_info {
struct subvol_uuid_search {
int mnt_fd;
#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
int uuid_tree_existed;
struct rb_root root_id_subvols;
struct rb_root local_subvols;
struct rb_root received_subvols;
struct rb_root path_subvols;
#endif
};
int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s);