- Ted
# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
#
# fs/Config.in | 9
# fs/Makefile | 4
# fs/mbcache.c | 716 +++++++++++++++++++++++++++++++++++++++++++
# include/linux/mbcache.h | 69 ++++
# 4 files changed, 797 insertions(+), 1 deletion(-)
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/14 tytso@snap.thunk.org 1.784
# Port of the 0.8.50 xattr-mbcache patch to 2.5.
#
# --------------------------------------------
#
diff -Nru a/fs/Config.in b/fs/Config.in
--- a/fs/Config.in Mon Oct 14 23:21:02 2002
+++ b/fs/Config.in Mon Oct 14 23:21:02 2002
@@ -171,6 +171,15 @@
define_tristate CONFIG_ZISOFS_FS n
fi
+# Meta block cache for Extended Attributes (ext2/ext3)
+if [ "$CONFIG_EXT2_FS_XATTR" = "y" -o "$CONFIG_EXT3_FS_XATTR" = "y" ]; then
+ if [ "$CONFIG_EXT2_FS" = "y" -o "$CONFIG_EXT3_FS" = "y" ]; then
+ define_tristate CONFIG_FS_MBCACHE y
+ elif [ "$CONFIG_EXT2_FS" = "m" -o "$CONFIG_EXT3_FS" = "m" ]; then
+ define_tristate CONFIG_FS_MBCACHE m
+ fi
+fi
+
mainmenu_option next_comment
comment 'Partition Types'
source fs/partitions/Config.in
diff -Nru a/fs/Makefile b/fs/Makefile
--- a/fs/Makefile Mon Oct 14 23:21:02 2002
+++ b/fs/Makefile Mon Oct 14 23:21:02 2002
@@ -6,7 +6,7 @@
#
export-objs := open.o dcache.o buffer.o bio.o inode.o dquot.o mpage.o aio.o \
- fcntl.o read_write.o
+ fcntl.o read_write.o mbcache.o
obj-y := open.o read_write.o devices.o file_table.o buffer.o \
bio.o super.o block_dev.o char_dev.o stat.o exec.o pipe.o \
@@ -29,6 +29,8 @@
obj-y += binfmt_script.o
obj-$(CONFIG_BINFMT_ELF) += binfmt_elf.o
+
+obj-$(CONFIG_FS_MBCACHE) += mbcache.o
obj-$(CONFIG_QUOTA) += dquot.o
obj-$(CONFIG_QFMT_V1) += quota_v1.o
diff -Nru a/fs/mbcache.c b/fs/mbcache.c
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/fs/mbcache.c Mon Oct 14 23:21:02 2002
@@ -0,0 +1,716 @@
+/*
+ * linux/fs/mbcache.c
+ * (C) 2001-2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+/*
+ * Filesystem Meta Information Block Cache (mbcache)
+ *
+ * The mbcache caches blocks of block devices that need to be located
+ * by their device/block number, as well as by other criteria (such
+ * as the block's contents).
+ *
+ * There can only be one cache entry in a cache per device and block number.
+ * Additional indexes need not be unique in this sense. The number of
+ * additional indexes (=other criteria) can be hardwired (at compile time)
+ * or specified at cache create time.
+ *
+ * Each cache entry is of fixed size. An entry may be `valid' or `invalid'
+ * in the cache. A valid entry is in the main hash tables of the cache,
+ * and may also be in the lru list. An invalid entry is not in any hashes
+ * or lists.
+ *
+ * A valid cache entry is only in the lru list if no handles refer to it.
+ * Invalid cache entries will be freed when the last handle to the cache
+ * entry is released.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/cache_def.h>
+#include <linux/version.h>
+#include <linux/init.h>
+#include <linux/mbcache.h>
+
+
+#ifdef MB_CACHE_DEBUG
+# define mb_debug(f...) do { \
+ printk(KERN_DEBUG f); \
+ printk("\n"); \
+ } while (0)
+#define mb_assert(c) do { if (!(c)) \
+ printk(KERN_ERR "assertion " #c " failed\n"); \
+ } while(0)
+#else
+# define mb_debug(f...) do { } while(0)
+# define mb_assert(c) do { } while(0)
+#endif
+#define mb_error(f...) do { \
+ printk(KERN_ERR f); \
+ printk("\n"); \
+ } while(0)
+
+MODULE_AUTHOR("Andreas Gruenbacher <a.gruenbacher@computer.org>");
+MODULE_DESCRIPTION("Meta block cache (for extended attributes)");
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
+MODULE_LICENSE("GPL");
+#endif
+
+EXPORT_SYMBOL(mb_cache_create);
+EXPORT_SYMBOL(mb_cache_shrink);
+EXPORT_SYMBOL(mb_cache_destroy);
+EXPORT_SYMBOL(mb_cache_entry_alloc);
+EXPORT_SYMBOL(mb_cache_entry_insert);
+EXPORT_SYMBOL(mb_cache_entry_release);
+EXPORT_SYMBOL(mb_cache_entry_takeout);
+EXPORT_SYMBOL(mb_cache_entry_free);
+EXPORT_SYMBOL(mb_cache_entry_dup);
+EXPORT_SYMBOL(mb_cache_entry_get);
+#if !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0)
+EXPORT_SYMBOL(mb_cache_entry_find_first);
+EXPORT_SYMBOL(mb_cache_entry_find_next);
+#endif
+
+
+/*
+ * Global data: list of all mbcache's, lru list, and a spinlock for
+ * accessing cache data structures on SMP machines. (The lru list is
+ * global across all mbcaches.)
+ */
+
+static LIST_HEAD(mb_cache_list);
+static LIST_HEAD(mb_cache_lru_list);
+static spinlock_t mb_cache_spinlock = SPIN_LOCK_UNLOCKED;
+
+static inline void
+mb_cache_lock(void)
+{
+ spin_lock(&mb_cache_spinlock);
+}
+
+static inline void
+mb_cache_unlock(void)
+{
+ spin_unlock(&mb_cache_spinlock);
+}
+
+static inline int
+mb_cache_indexes(struct mb_cache *cache)
+{
+#ifdef MB_CACHE_INDEXES_COUNT
+ return MB_CACHE_INDEXES_COUNT;
+#else
+ return cache->c_indexes_count;
+#endif
+}
+
+/*
+ * What the mbcache registers as to get shrunk dynamically.
+ */
+
+static void
+mb_cache_memory_pressure(int priority, unsigned int gfp_mask);
+
+static struct cache_definition mb_cache_definition = {
+ "mb_cache",
+ mb_cache_memory_pressure
+};
+
+
+static inline void
+__mb_cache_entry_takeout_lru(struct mb_cache_entry *ce)
+{
+ if (ce->e_lru_list.prev) {
+ list_del(&ce->e_lru_list);
+ ce->e_lru_list.prev = NULL;
+ }
+}
+
+
+static inline void
+__mb_cache_entry_into_lru(struct mb_cache_entry *ce)
+{
+ list_add(&ce->e_lru_list, &mb_cache_lru_list);
+}
+
+
+static inline int
+__mb_cache_entry_in_lru(struct mb_cache_entry *ce)
+{
+ return (ce->e_lru_list.prev != NULL);
+}
+
+
+/*
+ * Insert the cache entry into all hashes.
+ */
+static inline void
+__mb_cache_entry_link(struct mb_cache_entry *ce)
+{
+ struct mb_cache *cache = ce->e_cache;
+ unsigned int bucket = (ce->e_dev + ce->e_block) %
+ cache->c_bucket_count;
+ int n;
+
+ list_add(&ce->e_block_list, &cache->c_block_hash[bucket]);
+ for (n=0; n<mb_cache_indexes(cache); n++) {
+ bucket = ce->e_indexes[n].o_key % cache->c_bucket_count;
+ list_add(&ce->e_indexes[n].o_list,
+ &cache->c_indexes_hash[n][bucket]);
+ }
+}
+
+
+/*
+ * Remove the cache entry from all hashes.
+ */
+static inline void
+__mb_cache_entry_unlink(struct mb_cache_entry *ce)
+{
+ int n;
+
+ list_del(&ce->e_block_list);
+ ce->e_block_list.prev = NULL;
+ for (n=0; n<mb_cache_indexes(ce->e_cache); n++)
+ list_del(&ce->e_indexes[n].o_list);
+}
+
+
+static inline int
+__mb_cache_entry_is_linked(struct mb_cache_entry *ce)
+{
+ return (ce->e_block_list.prev != NULL);
+}
+
+
+static inline struct mb_cache_entry *
+__mb_cache_entry_read(struct mb_cache_entry *ce)
+{
+ __mb_cache_entry_takeout_lru(ce);
+ atomic_inc(&ce->e_used);
+ return ce;
+}
+
+
+static inline void
+__mb_cache_entry_forget(struct mb_cache_entry *ce)
+{
+ struct mb_cache *cache = ce->e_cache;
+
+ mb_assert(atomic_read(&ce->e_used) == 0);
+ atomic_dec(&cache->c_entry_count);
+ if (cache->c_op.free)
+ cache->c_op.free(ce);
+ kmem_cache_free(cache->c_entry_cache, ce);
+}
+
+
+static inline void
+__mb_cache_entry_release_unlock(struct mb_cache_entry *ce)
+{
+ if (atomic_dec_and_test(&ce->e_used)) {
+ if (__mb_cache_entry_is_linked(ce))
+ __mb_cache_entry_into_lru(ce);
+ else {
+ mb_cache_unlock();
+ __mb_cache_entry_forget(ce);
+ return;
+ }
+ }
+ mb_cache_unlock();
+}
+
+
+/*
+ * mb_cache_memory_pressure() memory pressure callback
+ *
+ * This function is called by the kernel memory management when memory
+ * gets low.
+ *
+ * @priority: Amount by which to shrink the cache (0 = highes priority)
+ * @gfp_mask: (ignored)
+ */
+static void
+mb_cache_memory_pressure(int priority, unsigned int gfp_mask)
+{
+ LIST_HEAD(free_list);
+ struct list_head *l;
+ int count = 0;
+
+ mb_cache_lock();
+ list_for_each_prev(l, &mb_cache_list) {
+ struct mb_cache *cache =
+ list_entry(l, struct mb_cache, c_cache_list);
+ mb_debug("cache %s (%d)", cache->c_name,
+ atomic_read(&cache->c_entry_count));
+ count += atomic_read(&cache->c_entry_count);
+ }
+ mb_debug("trying to free %d of %d entries",
+ count / (priority ? priority : 1), count);
+ if (priority)
+ count /= priority;
+ while (count && !list_empty(&mb_cache_lru_list)) {
+ struct mb_cache_entry *ce =
+ list_entry(mb_cache_lru_list.prev,
+ struct mb_cache_entry, e_lru_list);
+ list_del(&ce->e_lru_list);
+ list_add(&ce->e_lru_list, &free_list);
+ if (__mb_cache_entry_is_linked(ce))
+ __mb_cache_entry_unlink(ce);
+ count--;
+ }
+ mb_cache_unlock();
+ l = free_list.prev;
+ while (l != &free_list) {
+ struct mb_cache_entry *ce = list_entry(l,
+ struct mb_cache_entry, e_lru_list);
+ l = l->prev;
+ __mb_cache_entry_forget(ce);
+ }
+ if (count)
+ mb_debug("%d fewer entries freed", count);
+}
+
+
+/*
+ * mb_cache_create() create a new cache
+ *
+ * All entries in one cache are equal size. Cache entries may be from
+ * multiple devices. If this is the first mbcache created, registers
+ * the cache with kernel memory management. Returns NULL if no more
+ * memory was available.
+ *
+ * @name: name of the cache (informal)
+ * @cache_op: contains the callback called when freeing a cache entry
+ * @entry_size: The size of a cache entry, including
+ * struct mb_cache_entry
+ * @indexes_count: number of additional indexes in the cache. Must equal
+ * MB_CACHE_INDEXES_COUNT if the number of indexes is
+ * hardwired.
+ * @bucket_count: number of hash buckets
+ */
+struct mb_cache *
+mb_cache_create(const char *name, struct mb_cache_op *cache_op,
+ size_t entry_size, int indexes_count, int bucket_count)
+{
+ int m=0, n;
+ struct mb_cache *cache = NULL;
+
+ if(entry_size < sizeof(struct mb_cache_entry) +
+ indexes_count * sizeof(struct mb_cache_entry_index))
+ return NULL;
+
+ MOD_INC_USE_COUNT;
+ cache = kmalloc(sizeof(struct mb_cache) +
+ indexes_count * sizeof(struct list_head), GFP_KERNEL);
+ if (!cache)
+ goto fail;
+ cache->c_name = name;
+ if (cache_op)
+ cache->c_op.free = cache_op->free;
+ else
+ cache->c_op.free = NULL;
+ atomic_set(&cache->c_entry_count, 0);
+ cache->c_bucket_count = bucket_count;
+#ifdef MB_CACHE_INDEXES_COUNT
+ mb_assert(indexes_count == MB_CACHE_INDEXES_COUNT);
+#else
+ cache->c_indexes_count = indexes_count;
+#endif
+ cache->c_block_hash = kmalloc(bucket_count * sizeof(struct list_head),
+ GFP_KERNEL);
+ if (!cache->c_block_hash)
+ goto fail;
+ for (n=0; n<bucket_count; n++)
+ INIT_LIST_HEAD(&cache->c_block_hash[n]);
+ for (m=0; m<indexes_count; m++) {
+ cache->c_indexes_hash[m] = kmalloc(bucket_count *
+ sizeof(struct list_head),
+ GFP_KERNEL);
+ if (!cache->c_indexes_hash[m])
+ goto fail;
+ for (n=0; n<bucket_count; n++)
+ INIT_LIST_HEAD(&cache->c_indexes_hash[m][n]);
+ }
+ cache->c_entry_cache = kmem_cache_create(name, entry_size, 0,
+ 0 /*SLAB_POISON | SLAB_RED_ZONE*/, NULL, NULL);
+ if (!cache->c_entry_cache)
+ goto fail;
+
+ mb_cache_lock();
+ if (list_empty(&mb_cache_list))
+ register_cache(&mb_cache_definition);
+ list_add(&cache->c_cache_list, &mb_cache_list);
+ mb_cache_unlock();
+ return cache;
+
+fail:
+ if (cache) {
+ while (--m >= 0)
+ kfree(cache->c_indexes_hash[m]);
+ if (cache->c_block_hash)
+ kfree(cache->c_block_hash);
+ kfree(cache);
+ }
+ MOD_DEC_USE_COUNT;
+ return NULL;
+}
+
+
+/*
+ * mb_cache_shrink()
+ *
+ * Removes all cache entires of a device from the cache. All cache entries
+ * currently in use cannot be freed, and thus remain in the cache. All others
+ * are freed.
+ *
+ * @cache: which cache to shrink
+ * @dev: which device's cache entries to shrink
+ */
+void
+mb_cache_shrink(struct mb_cache *cache, dev_t dev)
+{
+ LIST_HEAD(free_list);
+ struct list_head *l;
+
+ mb_cache_lock();
+ l = mb_cache_lru_list.prev;
+ while (l != &mb_cache_lru_list) {
+ struct mb_cache_entry *ce =
+ list_entry(l, struct mb_cache_entry, e_lru_list);
+ l = l->prev;
+ if (ce->e_dev == dev) {
+ list_del(&ce->e_lru_list);
+ list_add(&ce->e_lru_list, &free_list);
+ if (__mb_cache_entry_is_linked(ce))
+ __mb_cache_entry_unlink(ce);
+ }
+ }
+ mb_cache_unlock();
+ l = free_list.prev;
+ while (l != &free_list) {
+ struct mb_cache_entry *ce =
+ list_entry(l, struct mb_cache_entry, e_lru_list);
+ l = l->prev;
+ __mb_cache_entry_forget(ce);
+ }
+}
+
+
+/*
+ * mb_cache_destroy()
+ *
+ * Shrinks the cache to its minimum possible size (hopefully 0 entries),
+ * and then destroys it. If this was the last mbcache, un-registers the
+ * mbcache from kernel memory management.
+ */
+void
+mb_cache_destroy(struct mb_cache *cache)
+{
+ LIST_HEAD(free_list);
+ struct list_head *l;
+ int n;
+
+ mb_cache_lock();
+ l = mb_cache_lru_list.prev;
+ while (l != &mb_cache_lru_list) {
+ struct mb_cache_entry *ce =
+ list_entry(l, struct mb_cache_entry, e_lru_list);
+ l = l->prev;
+ if (ce->e_cache == cache) {
+ list_del(&ce->e_lru_list);
+ list_add(&ce->e_lru_list, &free_list);
+ if (__mb_cache_entry_is_linked(ce))
+ __mb_cache_entry_unlink(ce);
+ }
+ }
+ list_del(&cache->c_cache_list);
+ if (list_empty(&mb_cache_list))
+ unregister_cache(&mb_cache_definition);
+ mb_cache_unlock();
+
+ l = free_list.prev;
+ while (l != &free_list) {
+ struct mb_cache_entry *ce =
+ list_entry(l, struct mb_cache_entry, e_lru_list);
+ l = l->prev;
+ __mb_cache_entry_forget(ce);
+ }
+
+ if (atomic_read(&cache->c_entry_count) > 0) {
+ mb_error("cache %s: %d orphaned entries",
+ cache->c_name,
+ atomic_read(&cache->c_entry_count));
+ }
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,3,0))
+ /* We don't have kmem_cache_destroy() in 2.2.x */
+ kmem_cache_shrink(cache->c_entry_cache);
+#else
+ kmem_cache_destroy(cache->c_entry_cache);
+#endif
+ for (n=0; n < mb_cache_indexes(cache); n++)
+ kfree(cache->c_indexes_hash[n]);
+ kfree(cache->c_block_hash);
+
+ kfree(cache);
+
+ MOD_DEC_USE_COUNT;
+}
+
+
+/*
+ * mb_cache_entry_alloc()
+ *
+ * Allocates a new cache entry. The new entry will not be valid initially,
+ * and thus cannot be looked up yet. It should be filled with data, and
+ * then inserted into the cache using mb_cache_entry_insert(). Returns NULL
+ * if no more memory was available.
+ */
+struct mb_cache_entry *
+mb_cache_entry_alloc(struct mb_cache *cache)
+{
+ struct mb_cache_entry *ce;
+
+ atomic_inc(&cache->c_entry_count);
+ ce = kmem_cache_alloc(cache->c_entry_cache, GFP_KERNEL);
+ if (ce) {
+ ce->e_lru_list.prev = NULL;
+ ce->e_block_list.prev = NULL;
+ ce->e_cache = cache;
+ atomic_set(&ce->e_used, 1);
+ }
+ return ce;
+}
+
+
+/*
+ * mb_cache_entry_insert()
+ *
+ * Inserts an entry that was allocated using mb_cache_entry_alloc() into
+ * the cache. After this, the cache entry can be looked up, but is not yet
+ * in the lru list as the caller still holds a handle to it. Returns 0 on
+ * success, or -EBUSY if a cache entry for that device + inode exists
+ * already (this may happen after a failed lookup, but when another process
+ * has inserted the same cache entry in the meantime).
+ *
+ * @dev: device the cache entry belongs to
+ * @block: block number
+ * @keys: array of additional keys. There must be indexes_count entries
+ * in the array (as specified when creating the cache).
+ */
+int
+mb_cache_entry_insert(struct mb_cache_entry *ce, dev_t dev,
+ unsigned long block, unsigned int keys[])
+{
+ struct mb_cache *cache = ce->e_cache;
+ unsigned int bucket = (dev + block) % cache->c_bucket_count;
+ struct list_head *l;
+ int error = -EBUSY, n;
+
+ mb_cache_lock();
+ list_for_each_prev(l, &cache->c_block_hash[bucket]) {
+ struct mb_cache_entry *ce =
+ list_entry(l, struct mb_cache_entry, e_block_list);
+ if (ce->e_dev == dev && ce->e_block == block)
+ goto out;
+ }
+ mb_assert(!__mb_cache_entry_is_linked(ce));
+ ce->e_dev = dev;
+ ce->e_block = block;
+ for (n=0; n<mb_cache_indexes(cache); n++)
+ ce->e_indexes[n].o_key = keys[n];
+ __mb_cache_entry_link(ce);
+out:
+ mb_cache_unlock();
+ return error;
+}
+
+
+/*
+ * mb_cache_entry_release()
+ *
+ * Release a handle to a cache entry. When the last handle to a cache entry
+ * is released it is either freed (if it is invalid) or otherwise inserted
+ * in to the lru list.
+ */
+void
+mb_cache_entry_release(struct mb_cache_entry *ce)
+{
+ mb_cache_lock();
+ __mb_cache_entry_release_unlock(ce);
+}
+
+
+/*
+ * mb_cache_entry_takeout()
+ *
+ * Take a cache entry out of the cache, making it invalid. The entry can later
+ * be re-inserted using mb_cache_entry_insert(), or released using
+ * mb_cache_entry_release().
+ */
+void
+mb_cache_entry_takeout(struct mb_cache_entry *ce)
+{
+ mb_cache_lock();
+ mb_assert(!__mb_cache_entry_in_lru(ce));
+ if (__mb_cache_entry_is_linked(ce))
+ __mb_cache_entry_unlink(ce);
+ mb_cache_unlock();
+}
+
+
+/*
+ * mb_cache_entry_free()
+ *
+ * This is equivalent to the sequence mb_cache_entry_takeout() --
+ * mb_cache_entry_release().
+ */
+void
+mb_cache_entry_free(struct mb_cache_entry *ce)
+{
+ mb_cache_lock();
+ mb_assert(!__mb_cache_entry_in_lru(ce));
+ if (__mb_cache_entry_is_linked(ce))
+ __mb_cache_entry_unlink(ce);
+ __mb_cache_entry_release_unlock(ce);
+}
+
+
+/*
+ * mb_cache_entry_dup()
+ *
+ * Duplicate a handle to a cache entry (does not duplicate the cache entry
+ * itself). After the call, both the old and the new handle must be released.
+ */
+struct mb_cache_entry *
+mb_cache_entry_dup(struct mb_cache_entry *ce)
+{
+ atomic_inc(&ce->e_used);
+ return ce;
+}
+
+
+/*
+ * mb_cache_entry_get()
+ *
+ * Get a cache entry by device / block number. (There can only be one entry
+ * in the cache per device and block.) Returns NULL if no such cache entry
+ * exists.
+ */
+struct mb_cache_entry *
+mb_cache_entry_get(struct mb_cache *cache, dev_t dev, unsigned long block)
+{
+ unsigned int bucket = (dev + block) % cache->c_bucket_count;
+ struct list_head *l;
+ struct mb_cache_entry *ce;
+
+ mb_cache_lock();
+ list_for_each(l, &cache->c_block_hash[bucket]) {
+ ce = list_entry(l, struct mb_cache_entry, e_block_list);
+ if (ce->e_dev == dev && ce->e_block == block) {
+ ce = __mb_cache_entry_read(ce);
+ goto cleanup;
+ }
+ }
+ ce = NULL;
+
+cleanup:
+ mb_cache_unlock();
+ return ce;
+}
+
+#if !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0)
+
+static struct mb_cache_entry *
+__mb_cache_entry_find(struct list_head *l, struct list_head *head,
+ int index, dev_t dev, unsigned int key)
+{
+ while (l != head) {
+ struct mb_cache_entry *ce =
+ list_entry(l, struct mb_cache_entry,
+ e_indexes[index].o_list);
+ if (ce->e_dev == dev &&
+ ce->e_indexes[index].o_key == key) {
+ ce = __mb_cache_entry_read(ce);
+ if (ce)
+ return ce;
+ }
+ l = l->next;
+ }
+ return NULL;
+}
+
+
+/*
+ * mb_cache_entry_find_first()
+ *
+ * Find the first cache entry on a given device with a certain key in
+ * an additional index. Additonal matches can be found with
+ * mb_cache_entry_find_next(). Returns NULL if no match was found.
+ *
+ * @cache: the cache to search
+ * @index: the number of the additonal index to search (0<=index<indexes_count)
+ * @dev: the device the cache entry should belong to
+ * @key: the key in the index
+ */
+struct mb_cache_entry *
+mb_cache_entry_find_first(struct mb_cache *cache, int index, dev_t dev,
+ unsigned int key)
+{
+ unsigned int bucket = key % cache->c_bucket_count;
+ struct list_head *l;
+ struct mb_cache_entry *ce;
+
+ mb_assert(index < mb_cache_indexes(cache));
+ mb_cache_lock();
+ l = cache->c_indexes_hash[index][bucket].next;
+ ce = __mb_cache_entry_find(l, &cache->c_indexes_hash[index][bucket],
+ index, dev, key);
+ mb_cache_unlock();
+ return ce;
+}
+
+
+/*
+ * mb_cache_entry_find_next()
+ *
+ * Find the next cache entry on a given device with a certain key in an
+ * additional index. Returns NULL if no match could be found. The previous
+ * entry is atomatically released, so that mb_cache_entry_find_next() can
+ * be called like this:
+ *
+ * entry = mb_cache_entry_find_first();
+ * while (entry) {
+ * ...
+ * entry = mb_cache_entry_find_next(entry, ...);
+ * }
+ *
+ * @prev: The previous match
+ * @index: the number of the additonal index to search (0<=index<indexes_count)
+ * @dev: the device the cache entry should belong to
+ * @key: the key in the index
+ */
+struct mb_cache_entry *
+mb_cache_entry_find_next(struct mb_cache_entry *prev, int index, dev_t dev,
+ unsigned int key)
+{
+ struct mb_cache *cache = prev->e_cache;
+ unsigned int bucket = key % cache->c_bucket_count;
+ struct list_head *l;
+ struct mb_cache_entry *ce;
+
+ mb_assert(index < mb_cache_indexes(cache));
+ mb_cache_lock();
+ l = prev->e_indexes[index].o_list.next;
+ ce = __mb_cache_entry_find(l, &cache->c_indexes_hash[index][bucket],
+ index, dev, key);
+ __mb_cache_entry_release_unlock(prev);
+ return ce;
+}
+
+#endif /* !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0) */
diff -Nru a/include/linux/mbcache.h b/include/linux/mbcache.h
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/include/linux/mbcache.h Mon Oct 14 23:21:02 2002
@@ -0,0 +1,69 @@
+/*
+ File: linux/mbcache.h
+
+ (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+/* Hardwire the number of additional indexes */
+#define MB_CACHE_INDEXES_COUNT 1
+
+struct mb_cache_entry;
+
+struct mb_cache_op {
+ void (*free)(struct mb_cache_entry *);
+};
+
+struct mb_cache {
+ struct list_head c_cache_list;
+ const char *c_name;
+ struct mb_cache_op c_op;
+ atomic_t c_entry_count;
+ int c_bucket_count;
+#ifndef MB_CACHE_INDEXES_COUNT
+ int c_indexes_count;
+#endif
+ kmem_cache_t *c_entry_cache;
+ struct list_head *c_block_hash;
+ struct list_head *c_indexes_hash[0];
+};
+
+struct mb_cache_entry_index {
+ struct list_head o_list;
+ unsigned int o_key;
+};
+
+struct mb_cache_entry {
+ struct list_head e_lru_list;
+ struct mb_cache *e_cache;
+ atomic_t e_used;
+ dev_t e_dev;
+ unsigned long e_block;
+ struct list_head e_block_list;
+ struct mb_cache_entry_index e_indexes[0];
+};
+
+/* Functions on caches */
+
+struct mb_cache * mb_cache_create(const char *, struct mb_cache_op *, size_t,
+ int, int);
+void mb_cache_shrink(struct mb_cache *, dev_t);
+void mb_cache_destroy(struct mb_cache *);
+
+/* Functions on cache entries */
+
+struct mb_cache_entry *mb_cache_entry_alloc(struct mb_cache *);
+int mb_cache_entry_insert(struct mb_cache_entry *, dev_t, unsigned long,
+ unsigned int[]);
+void mb_cache_entry_rehash(struct mb_cache_entry *, unsigned int[]);
+void mb_cache_entry_release(struct mb_cache_entry *);
+void mb_cache_entry_takeout(struct mb_cache_entry *);
+void mb_cache_entry_free(struct mb_cache_entry *);
+struct mb_cache_entry *mb_cache_entry_dup(struct mb_cache_entry *);
+struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *, dev_t,
+ unsigned long);
+#if !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0)
+struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache, int,
+ dev_t, unsigned int);
+struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache_entry *, int,
+ dev_t, unsigned int);
+#endif
-
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