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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 07/17] tools/xenstore: change per-domain node accounting interface
Rework the interface and the internals of the per-domain node
accounting:
- rename the functions to domain_nbentry_*() in order to better match
the related counter name
- switch from node pointer to domid as interface, as all nodes have the
owner filled in
- use a common internal function for adding a value to the counter
For the transaction case add a helper function to get the list head
of the per-transaction changed domains, enabling to eliminate the
transaction_entry_*() functions.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V3:
- add get_node_owner() (Julien Grall)
- rename domain_nbentry_add() parameter (Julien Grall)
- avoid negative entry count (Julien Grall)
---
tools/xenstore/xenstored_core.c | 33 ++++---
tools/xenstore/xenstored_domain.c | 126 ++++++++++++-------------
tools/xenstore/xenstored_domain.h | 10 +-
tools/xenstore/xenstored_transaction.c | 15 +--
tools/xenstore/xenstored_transaction.h | 7 +-
5 files changed, 86 insertions(+), 105 deletions(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index fb4379e67c..561fb121d3 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -700,6 +700,11 @@ int do_tdb_delete(struct connection *conn, TDB_DATA *key,
return 0;
}
+static unsigned int get_node_owner(const struct node *node)
+{
+ return node->perms.p[0].id;
+}
+
/*
* If it fails, returns NULL and sets errno.
* Temporary memory allocations will be done with ctx.
@@ -752,13 +757,13 @@ struct node *read_node(struct connection *conn, const
void *ctx,
/* Permissions are struct xs_permissions. */
node->perms.p = hdr->perms;
- node->acc.domid = node->perms.p[0].id;
+ node->acc.domid = get_node_owner(node);
node->acc.memory = data.dsize;
if (domain_adjust_node_perms(node))
goto error;
/* If owner is gone reset currently accounted memory size. */
- if (node->acc.domid != node->perms.p[0].id)
+ if (node->acc.domid != get_node_owner(node))
node->acc.memory = 0;
/* Data is binary blob (usually ascii, no nul). */
@@ -1459,7 +1464,7 @@ static void destroy_node_rm(struct connection *conn,
struct node *node)
static int destroy_node(struct connection *conn, struct node *node)
{
destroy_node_rm(conn, node);
- domain_entry_dec(conn, node);
+ domain_nbentry_dec(conn, get_node_owner(node));
/*
* It is not possible to easily revert the changes in a transaction.
@@ -1498,7 +1503,7 @@ static struct node *create_node(struct connection *conn,
const void *ctx,
for (i = node; i; i = i->parent) {
/* i->parent is set for each new node, so check quota. */
if (i->parent &&
- domain_entry(conn) >= quota_nb_entry_per_domain) {
+ domain_nbentry(conn) >= quota_nb_entry_per_domain) {
ret = ENOSPC;
goto err;
}
@@ -1509,7 +1514,7 @@ static struct node *create_node(struct connection *conn,
const void *ctx,
/* Account for new node */
if (i->parent) {
- if (domain_entry_inc(conn, i)) {
+ if (domain_nbentry_inc(conn, get_node_owner(i))) {
destroy_node_rm(conn, i);
return NULL;
}
@@ -1662,7 +1667,7 @@ static int delnode_sub(const void *ctx, struct connection
*conn,
watch_exact = strcmp(root, node->name);
fire_watches(conn, ctx, node->name, node, watch_exact, NULL);
- domain_entry_dec(conn, node);
+ domain_nbentry_dec(conn, get_node_owner(node));
return WALK_TREE_RM_CHILDENTRY;
}
@@ -1798,29 +1803,29 @@ static int do_set_perms(const void *ctx, struct
connection *conn,
/* Unprivileged domains may not change the owner. */
if (domain_is_unprivileged(conn) &&
- perms.p[0].id != node->perms.p[0].id)
+ perms.p[0].id != get_node_owner(node))
return EPERM;
old_perms = node->perms;
- domain_entry_dec(conn, node);
+ domain_nbentry_dec(conn, get_node_owner(node));
node->perms = perms;
- if (domain_entry_inc(conn, node)) {
+ if (domain_nbentry_inc(conn, get_node_owner(node))) {
node->perms = old_perms;
/*
* This should never fail because we had a reference on the
* domain before and Xenstored is single-threaded.
*/
- domain_entry_inc(conn, node);
+ domain_nbentry_inc(conn, get_node_owner(node));
return ENOMEM;
}
if (write_node(conn, node, false)) {
int saved_errno = errno;
- domain_entry_dec(conn, node);
+ domain_nbentry_dec(conn, get_node_owner(node));
node->perms = old_perms;
/* No failure possible as above. */
- domain_entry_inc(conn, node);
+ domain_nbentry_inc(conn, get_node_owner(node));
errno = saved_errno;
return errno;
@@ -2392,7 +2397,7 @@ void setup_structure(bool live_update)
manual_node("/tool/xenstored", NULL);
manual_node("@releaseDomain", NULL);
manual_node("@introduceDomain", NULL);
- domain_entry_fix(dom0_domid, 5, true);
+ domain_nbentry_fix(dom0_domid, 5, true);
}
check_store();
@@ -3400,7 +3405,7 @@ void read_state_node(const void *ctx, const void *state)
if (write_node_raw(NULL, &key, node, true))
barf("write node error restoring node");
- if (domain_entry_inc(&conn, node))
+ if (domain_nbentry_inc(&conn, get_node_owner(node)))
barf("node accounting error restoring node");
talloc_free(node);
diff --git a/tools/xenstore/xenstored_domain.c
b/tools/xenstore/xenstored_domain.c
index 3a2ab5d87e..edfe5809be 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -249,7 +249,7 @@ static int domain_tree_remove_sub(const void *ctx, struct
connection *conn,
domain->nbentry--;
node->perms.p[0].id = priv_domid;
node->acc.memory = 0;
- domain_entry_inc(NULL, node);
+ domain_nbentry_inc(NULL, priv_domid);
if (write_node_raw(NULL, &key, node, true)) {
/* That's unfortunate. We only can try to continue. */
syslog(LOG_ERR,
@@ -561,7 +561,7 @@ int acc_fix_domains(struct list_head *head, bool update)
int cnt;
list_for_each_entry(cd, head, list) {
- cnt = domain_entry_fix(cd->domid, cd->nbentry, update);
+ cnt = domain_nbentry_fix(cd->domid, cd->nbentry, update);
if (!update) {
if (cnt >= quota_nb_entry_per_domain)
return ENOSPC;
@@ -606,8 +606,8 @@ static struct changed_domain *acc_get_changed_domain(const
void *ctx,
return cd;
}
-int acc_add_dom_nbentry(const void *ctx, struct list_head *head, int val,
- unsigned int domid)
+static int acc_add_dom_nbentry(const void *ctx, struct list_head *head, int
val,
+ unsigned int domid)
{
struct changed_domain *cd;
@@ -991,30 +991,6 @@ void domain_deinit(void)
xenevtchn_unbind(xce_handle, virq_port);
}
-int domain_entry_inc(struct connection *conn, struct node *node)
-{
- struct domain *d;
- unsigned int domid;
-
- if (!node->perms.p)
- return 0;
-
- domid = node->perms.p[0].id;
-
- if (conn && conn->transaction) {
- transaction_entry_inc(conn->transaction, domid);
- } else {
- d = (conn && domid == conn->id && conn->domain) ? conn->domain
- : find_or_alloc_existing_domain(domid);
- if (d)
- d->nbentry++;
- else
- return ENOMEM;
- }
-
- return 0;
-}
-
/*
* Check whether a domain was created before or after a specific generation
* count (used for testing whether a node permission is older than a domain).
@@ -1082,62 +1058,76 @@ int domain_adjust_node_perms(struct node *node)
return 0;
}
-void domain_entry_dec(struct connection *conn, struct node *node)
+static int domain_nbentry_add(struct connection *conn, unsigned int domid,
+ int add, bool no_dom_alloc)
{
struct domain *d;
- unsigned int domid;
-
- if (!node->perms.p)
- return;
+ struct list_head *head;
+ int ret;
- domid = node->perms.p ? node->perms.p[0].id : conn->id;
+ if (conn && domid == conn->id && conn->domain)
+ d = conn->domain;
+ else if (no_dom_alloc) {
+ d = find_domain_struct(domid);
+ if (!d) {
+ errno = ENOENT;
+ corrupt(conn, "Missing domain %u\n", domid);
+ return -1;
+ }
+ } else {
+ d = find_or_alloc_existing_domain(domid);
+ if (!d) {
+ errno = ENOMEM;
+ return -1;
+ }
+ }
if (conn && conn->transaction) {
- transaction_entry_dec(conn->transaction, domid);
- } else {
- d = (conn && domid == conn->id && conn->domain) ? conn->domain
- : find_domain_struct(domid);
- if (d) {
- d->nbentry--;
- } else {
- errno = ENOENT;
- corrupt(conn,
- "Node \"%s\" owned by non-existing domain %u\n",
- node->name, domid);
+ head = transaction_get_changed_domains(conn->transaction);
+ ret = acc_add_dom_nbentry(conn->transaction, head, add, domid);
+ if (errno) {
+ fail_transaction(conn->transaction);
+ return -1;
}
+ /*
+ * In a transaction when a node is being added/removed AND the
+ * same node has been added/removed outside the transaction in
+ * parallel, the resulting number of nodes will be wrong. This
+ * is no problem, as the transaction will fail due to the
+ * resulting conflict.
+ * In the node remove case the resulting number can be even
+ * negative, which should be avoided.
+ */
+ return max(d->nbentry + ret, 0);
}
+
+ d->nbentry += add;
+
+ return d->nbentry;
}
-int domain_entry_fix(unsigned int domid, int num, bool update)
+int domain_nbentry_inc(struct connection *conn, unsigned int domid)
{
- struct domain *d;
- int cnt;
+ return (domain_nbentry_add(conn, domid, 1, false) < 0) ? errno : 0;
+}
- if (update) {
- d = find_domain_struct(domid);
- assert(d);
- } else {
- /*
- * We are called first with update == false in order to catch
- * any error. So do a possible allocation and check for error
- * only in this case, as in the case of update == true nothing
- * can go wrong anymore as the allocation already happened.
- */
- d = find_or_alloc_existing_domain(domid);
- if (!d)
- return -1;
- }
+int domain_nbentry_dec(struct connection *conn, unsigned int domid)
+{
+ return (domain_nbentry_add(conn, domid, -1, true) < 0) ? errno : 0;
+}
- cnt = d->nbentry + num;
- assert(cnt >= 0);
+int domain_nbentry_fix(unsigned int domid, int num, bool update)
+{
+ int ret;
- if (update)
- d->nbentry = cnt;
+ ret = domain_nbentry_add(NULL, domid, update ? num : 0, update);
+ if (ret < 0 || update)
+ return ret;
- return domid_is_unprivileged(domid) ? cnt : 0;
+ return domid_is_unprivileged(domid) ? ret + num : 0;
}
-int domain_entry(struct connection *conn)
+int domain_nbentry(struct connection *conn)
{
return (domain_is_unprivileged(conn))
? conn->domain->nbentry
diff --git a/tools/xenstore/xenstored_domain.h
b/tools/xenstore/xenstored_domain.h
index 9e20d2b17d..1e402f2609 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -66,10 +66,10 @@ int domain_adjust_node_perms(struct node *node);
int domain_alloc_permrefs(struct node_perms *perms);
/* Quota manipulation */
-int domain_entry_inc(struct connection *conn, struct node *);
-void domain_entry_dec(struct connection *conn, struct node *);
-int domain_entry_fix(unsigned int domid, int num, bool update);
-int domain_entry(struct connection *conn);
+int domain_nbentry_inc(struct connection *conn, unsigned int domid);
+int domain_nbentry_dec(struct connection *conn, unsigned int domid);
+int domain_nbentry_fix(unsigned int domid, int num, bool update);
+int domain_nbentry(struct connection *conn);
int domain_memory_add(unsigned int domid, int mem, bool no_quota_check);
/*
@@ -99,8 +99,6 @@ void domain_outstanding_domid_dec(unsigned int domid);
int domain_get_quota(const void *ctx, struct connection *conn,
unsigned int domid);
int acc_fix_domains(struct list_head *head, bool update);
-int acc_add_dom_nbentry(const void *ctx, struct list_head *head, int val,
- unsigned int domid);
/* Write rate limiting */
diff --git a/tools/xenstore/xenstored_transaction.c
b/tools/xenstore/xenstored_transaction.c
index c009c67989..82e5e66c18 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -548,20 +548,9 @@ int do_transaction_end(const void *ctx, struct connection
*conn,
return 0;
}
-void transaction_entry_inc(struct transaction *trans, unsigned int domid)
+struct list_head *transaction_get_changed_domains(struct transaction *trans)
{
- if (!acc_add_dom_nbentry(trans, &trans->changed_domains, 1, domid)) {
- /* Let the transaction fail. */
- trans->fail = true;
- }
-}
-
-void transaction_entry_dec(struct transaction *trans, unsigned int domid)
-{
- if (!acc_add_dom_nbentry(trans, &trans->changed_domains, -1, domid)) {
- /* Let the transaction fail. */
- trans->fail = true;
- }
+ return &trans->changed_domains;
}
void fail_transaction(struct transaction *trans)
diff --git a/tools/xenstore/xenstored_transaction.h
b/tools/xenstore/xenstored_transaction.h
index 3417303f94..b6f8cb7d0a 100644
--- a/tools/xenstore/xenstored_transaction.h
+++ b/tools/xenstore/xenstored_transaction.h
@@ -36,10 +36,6 @@ int do_transaction_end(const void *ctx, struct connection
*conn,
struct transaction *transaction_lookup(struct connection *conn, uint32_t id);
-/* inc/dec entry number local to trans while changing a node */
-void transaction_entry_inc(struct transaction *trans, unsigned int domid);
-void transaction_entry_dec(struct transaction *trans, unsigned int domid);
-
/* This node was accessed. */
int __must_check access_node(struct connection *conn, struct node *node,
enum node_access_type type, TDB_DATA *key);
@@ -54,6 +50,9 @@ void transaction_prepend(struct connection *conn, const char
*name,
/* Mark the transaction as failed. This will prevent it to be committed. */
void fail_transaction(struct transaction *trans);
+/* Get the list head of the changed domains. */
+struct list_head *transaction_get_changed_domains(struct transaction *trans);
+
void conn_delete_all_transactions(struct connection *conn);
int check_transactions(struct hashtable *hash);
--
2.35.3
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