/*
- * linux/fs/revoke.c
+ * linux/fs/jbd/revoke.c
*
* Written by Stephen C. Tweedie <sct@redhat.com>, 2000
*
* need do nothing.
* RevokeValid set, Revoked set:
* buffer has been revoked.
+ *
+ * Locking rules:
+ * We keep two hash tables of revoke records. One hashtable belongs to the
+ * running transaction (is pointed to by journal->j_revoke), the other one
+ * belongs to the committing transaction. Accesses to the second hash table
+ * happen only from the kjournald and no other thread touches this table. Also
+ * journal_switch_revoke_table() which switches which hashtable belongs to the
+ * running and which to the committing transaction is called only from
+ * kjournald. Therefore we need no locks when accessing the hashtable belonging
+ * to the committing transaction.
+ *
+ * All users operating on the hash table belonging to the running transaction
+ * have a handle to the transaction. Therefore they are safe from kjournald
+ * switching hash tables under them. For operations on the lists of entries in
+ * the hash table j_revoke_lock is used.
+ *
+ * Finally, also replay code uses the hash tables but at this moment noone else
+ * can touch them (filesystem isn't mounted yet) and hence no locking is
+ * needed.
*/
#ifndef __KERNEL__
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/list.h>
-#include <linux/smp_lock.h>
#include <linux/init.h>
#endif
+#include <linux/log2.h>
static struct kmem_cache *revoke_record_cache;
static struct kmem_cache *revoke_table_cache;
oom:
if (!journal_oom_retry)
return -ENOMEM;
- jbd_debug(1, "ENOMEM in %s, retrying\n", __FUNCTION__);
+ jbd_debug(1, "ENOMEM in %s, retrying\n", __func__);
yield();
goto repeat;
}
return NULL;
}
+void journal_destroy_revoke_caches(void)
+{
+ if (revoke_record_cache) {
+ kmem_cache_destroy(revoke_record_cache);
+ revoke_record_cache = NULL;
+ }
+ if (revoke_table_cache) {
+ kmem_cache_destroy(revoke_table_cache);
+ revoke_table_cache = NULL;
+ }
+}
+
int __init journal_init_revoke_caches(void)
{
+ J_ASSERT(!revoke_record_cache);
+ J_ASSERT(!revoke_table_cache);
+
revoke_record_cache = kmem_cache_create("revoke_record",
sizeof(struct jbd_revoke_record_s),
- 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
- if (revoke_record_cache == 0)
- return -ENOMEM;
+ 0,
+ SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
+ NULL);
+ if (!revoke_record_cache)
+ goto record_cache_failure;
revoke_table_cache = kmem_cache_create("revoke_table",
sizeof(struct jbd_revoke_table_s),
- 0, 0, NULL, NULL);
- if (revoke_table_cache == 0) {
- kmem_cache_destroy(revoke_record_cache);
- revoke_record_cache = NULL;
- return -ENOMEM;
- }
+ 0, SLAB_TEMPORARY, NULL);
+ if (!revoke_table_cache)
+ goto table_cache_failure;
+
return 0;
-}
-void journal_destroy_revoke_caches(void)
-{
- kmem_cache_destroy(revoke_record_cache);
- revoke_record_cache = NULL;
- kmem_cache_destroy(revoke_table_cache);
- revoke_table_cache = NULL;
+table_cache_failure:
+ journal_destroy_revoke_caches();
+record_cache_failure:
+ return -ENOMEM;
}
-/* Initialise the revoke table for a given journal to a given size. */
-
-int journal_init_revoke(journal_t *journal, int hash_size)
+static struct jbd_revoke_table_s *journal_init_revoke_table(int hash_size)
{
- int shift, tmp;
+ int shift = 0;
+ int tmp = hash_size;
+ struct jbd_revoke_table_s *table;
- J_ASSERT (journal->j_revoke_table[0] == NULL);
+ table = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL);
+ if (!table)
+ goto out;
- shift = 0;
- tmp = hash_size;
while((tmp >>= 1UL) != 0UL)
shift++;
- journal->j_revoke_table[0] = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL);
- if (!journal->j_revoke_table[0])
- return -ENOMEM;
- journal->j_revoke = journal->j_revoke_table[0];
-
- /* Check that the hash_size is a power of two */
- J_ASSERT ((hash_size & (hash_size-1)) == 0);
-
- journal->j_revoke->hash_size = hash_size;
-
- journal->j_revoke->hash_shift = shift;
-
- journal->j_revoke->hash_table =
+ table->hash_size = hash_size;
+ table->hash_shift = shift;
+ table->hash_table =
kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL);
- if (!journal->j_revoke->hash_table) {
- kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]);
- journal->j_revoke = NULL;
- return -ENOMEM;
+ if (!table->hash_table) {
+ kmem_cache_free(revoke_table_cache, table);
+ table = NULL;
+ goto out;
}
for (tmp = 0; tmp < hash_size; tmp++)
- INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]);
+ INIT_LIST_HEAD(&table->hash_table[tmp]);
- journal->j_revoke_table[1] = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL);
- if (!journal->j_revoke_table[1]) {
- kfree(journal->j_revoke_table[0]->hash_table);
- kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]);
- return -ENOMEM;
- }
+out:
+ return table;
+}
- journal->j_revoke = journal->j_revoke_table[1];
+static void journal_destroy_revoke_table(struct jbd_revoke_table_s *table)
+{
+ int i;
+ struct list_head *hash_list;
+
+ for (i = 0; i < table->hash_size; i++) {
+ hash_list = &table->hash_table[i];
+ J_ASSERT(list_empty(hash_list));
+ }
- /* Check that the hash_size is a power of two */
- J_ASSERT ((hash_size & (hash_size-1)) == 0);
+ kfree(table->hash_table);
+ kmem_cache_free(revoke_table_cache, table);
+}
- journal->j_revoke->hash_size = hash_size;
+/* Initialise the revoke table for a given journal to a given size. */
+int journal_init_revoke(journal_t *journal, int hash_size)
+{
+ J_ASSERT(journal->j_revoke_table[0] == NULL);
+ J_ASSERT(is_power_of_2(hash_size));
- journal->j_revoke->hash_shift = shift;
+ journal->j_revoke_table[0] = journal_init_revoke_table(hash_size);
+ if (!journal->j_revoke_table[0])
+ goto fail0;
- journal->j_revoke->hash_table =
- kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL);
- if (!journal->j_revoke->hash_table) {
- kfree(journal->j_revoke_table[0]->hash_table);
- kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]);
- kmem_cache_free(revoke_table_cache, journal->j_revoke_table[1]);
- journal->j_revoke = NULL;
- return -ENOMEM;
- }
+ journal->j_revoke_table[1] = journal_init_revoke_table(hash_size);
+ if (!journal->j_revoke_table[1])
+ goto fail1;
- for (tmp = 0; tmp < hash_size; tmp++)
- INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]);
+ journal->j_revoke = journal->j_revoke_table[1];
spin_lock_init(&journal->j_revoke_lock);
return 0;
-}
-/* Destoy a journal's revoke table. The table must already be empty! */
+fail1:
+ journal_destroy_revoke_table(journal->j_revoke_table[0]);
+fail0:
+ return -ENOMEM;
+}
+/* Destroy a journal's revoke table. The table must already be empty! */
void journal_destroy_revoke(journal_t *journal)
{
- struct jbd_revoke_table_s *table;
- struct list_head *hash_list;
- int i;
-
- table = journal->j_revoke_table[0];
- if (!table)
- return;
-
- for (i=0; i<table->hash_size; i++) {
- hash_list = &table->hash_table[i];
- J_ASSERT (list_empty(hash_list));
- }
-
- kfree(table->hash_table);
- kmem_cache_free(revoke_table_cache, table);
- journal->j_revoke = NULL;
-
- table = journal->j_revoke_table[1];
- if (!table)
- return;
-
- for (i=0; i<table->hash_size; i++) {
- hash_list = &table->hash_table[i];
- J_ASSERT (list_empty(hash_list));
- }
-
- kfree(table->hash_table);
- kmem_cache_free(revoke_table_cache, table);
journal->j_revoke = NULL;
+ if (journal->j_revoke_table[0])
+ journal_destroy_revoke_table(journal->j_revoke_table[0]);
+ if (journal->j_revoke_table[1])
+ journal_destroy_revoke_table(journal->j_revoke_table[1]);
}
* the second time we would still have a pending revoke to cancel. So,
* do not trust the Revoked bit on buffers unless RevokeValid is also
* set.
- *
- * The caller must have the journal locked.
*/
int journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
{
/*
* Write revoke records to the journal for all entries in the current
* revoke hash, deleting the entries as we go.
- *
- * Called with the journal lock held.
*/
-
void journal_write_revoke_records(journal_t *journal,
transaction_t *transaction)
{
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff