From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Create a simple 'big array' data structure for storage of fixed-size
metadata records that will be used to reconstruct a btree index. For
repair operations, the most important operations are append, iterate,
and sort; while supported, get and put are not for frequent use.
For the initial implementation we will use linked-list containers,
though a subsequent patch will restructure the backend to avoid using
pinned kernel memory.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/Makefile | 1
fs/xfs/scrub/array.c | 283 ++++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/array.h | 53 +++++++++
3 files changed, 337 insertions(+)
create mode 100644 fs/xfs/scrub/array.c
create mode 100644 fs/xfs/scrub/array.h
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 9c5542ef0495..bd781606719f 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -165,6 +165,7 @@ xfs-$(CONFIG_XFS_QUOTA) += scrub/quota.o
ifeq ($(CONFIG_XFS_ONLINE_REPAIR),y)
xfs-y += $(addprefix scrub/, \
agheader_repair.o \
+ array.o \
bitmap.o \
repair.o \
)
diff --git a/fs/xfs/scrub/array.c b/fs/xfs/scrub/array.c
new file mode 100644
index 000000000000..7871e8dcad5c
--- /dev/null
+++ b/fs/xfs/scrub/array.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "scrub/array.h"
+
+/*
+ * XFS Fixed-Size Big Memory Array
+ * ===============================
+ * The big memory array uses a list to store large numbers of fixed-size
+ * records in memory. Access to the array is performed via indexed get and put
+ * methods, and an append method is provided for convenience. Array elements
+ * can be set to all zeroes, which means that the entry is NULL and will be
+ * skipped during iteration.
+ */
+
+struct xa_item {
+ struct list_head list;
+ /* array item comes after here */
+};
+
+#define XA_ITEM_SIZE(sz) (sizeof(struct xa_item) + (sz))
+
+/* Initialize a big memory array. */
+struct xfbma *
+xfbma_init(
+ size_t obj_size)
+{
+ struct xfbma *array;
+ int error;
+
+ error = -ENOMEM;
+ array = kmem_alloc(sizeof(struct xfbma) + obj_size,
+ KM_NOFS | KM_MAYFAIL);
+ if (!array)
+ return ERR_PTR(error);
+
+ array->obj_size = obj_size;
+ array->nr = 0;
+ INIT_LIST_HEAD(&array->list);
+ memset(&array->cache, 0, sizeof(array->cache));
+
+ return array;
+}
+
+void
+xfbma_destroy(
+ struct xfbma *array)
+{
+ struct xa_item *item, *n;
+
+ list_for_each_entry_safe(item, n, &array->list, list) {
+ list_del(&item->list);
+ kmem_free(item);
+ }
+ kmem_free(array);
+}
+
+/* Find something in the cache. */
+static struct xa_item *
+xfbma_cache_lookup(
+ struct xfbma *array,
+ uint64_t nr)
+{
+ uint64_t i;
+
+ for (i = 0; i < XMA_CACHE_SIZE; i++)
+ if (array->cache[i].nr == nr && array->cache[i].item)
+ return array->cache[i].item;
+ return NULL;
+}
+
+/* Invalidate the lookup cache. */
+static void
+xfbma_cache_invalidate(
+ struct xfbma *array)
+{
+ memset(array->cache, 0, sizeof(array->cache));
+}
+
+/* Put something in the cache. */
+static void
+xfbma_cache_store(
+ struct xfbma *array,
+ uint64_t nr,
+ struct xa_item *item)
+{
+ memmove(array->cache + 1, array->cache,
+ sizeof(struct xma_cache) * (XMA_CACHE_SIZE - 1));
+ array->cache[0].item = item;
+ array->cache[0].nr = nr;
+}
+
+/* Find a particular array item. */
+static struct xa_item *
+xfbma_lookup(
+ struct xfbma *array,
+ uint64_t nr)
+{
+ struct xa_item *item;
+ uint64_t i;
+
+ if (nr >= array->nr) {
+ ASSERT(0);
+ return NULL;
+ }
+
+ item = xfbma_cache_lookup(array, nr);
+ if (item)
+ return item;
+
+ i = 0;
+ list_for_each_entry(item, &array->list, list) {
+ if (i == nr) {
+ xfbma_cache_store(array, nr, item);
+ return item;
+ }
+ i++;
+ }
+ return NULL;
+}
+
+/* Get an element from the array. */
+int
+xfbma_get(
+ struct xfbma *array,
+ uint64_t nr,
+ void *ptr)
+{
+ struct xa_item *item;
+
+ item = xfbma_lookup(array, nr);
+ if (!item)
+ return -ENODATA;
+ memcpy(ptr, item + 1, array->obj_size);
+ return 0;
+}
+
+/* Put an element in the array. */
+int
+xfbma_set(
+ struct xfbma *array,
+ uint64_t nr,
+ void *ptr)
+{
+ struct xa_item *item;
+
+ item = xfbma_lookup(array, nr);
+ if (!item)
+ return -ENODATA;
+ memcpy(item + 1, ptr, array->obj_size);
+ return 0;
+}
+
+/* Is this array element NULL? */
+bool
+xfbma_is_null(
+ struct xfbma *array,
+ void *ptr)
+{
+ return !memchr_inv(ptr, 0, array->obj_size);
+}
+
+/* Put an element anywhere in the array that isn't NULL. */
+int
+xfbma_insert_anywhere(
+ struct xfbma *array,
+ void *ptr)
+{
+ struct xa_item *item;
+
+ /* Find a null slot to put it in. */
+ list_for_each_entry(item, &array->list, list) {
+ if (!xfbma_is_null(array, item + 1))
+ continue;
+ memcpy(item + 1, ptr, array->obj_size);
+ return 0;
+ }
+
+ /* No null slots, just dump it on the end. */
+ return xfbma_append(array, ptr);
+}
+
+/* NULL an element in the array. */
+int
+xfbma_nullify(
+ struct xfbma *array,
+ uint64_t nr)
+{
+ struct xa_item *item;
+
+ item = xfbma_lookup(array, nr);
+ if (!item)
+ return -ENODATA;
+ memset(item + 1, 0, array->obj_size);
+ return 0;
+}
+
+/* Append an element to the array. */
+int
+xfbma_append(
+ struct xfbma *array,
+ void *ptr)
+{
+ struct xa_item *item;
+
+ item = kmem_alloc(XA_ITEM_SIZE(array->obj_size), KM_NOFS | KM_MAYFAIL);
+ if (!item)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&item->list);
+ memcpy(item + 1, ptr, array->obj_size);
+ list_add_tail(&item->list, &array->list);
+ array->nr++;
+ return 0;
+}
+
+/*
+ * Iterate every element in this array, freeing each element as we go.
+ * Array elements will be shifted down.
+ */
+int
+xfbma_iter_del(
+ struct xfbma *array,
+ xfbma_iter_fn iter_fn,
+ void *priv)
+{
+ struct xa_item *item, *n;
+ int error = 0;
+
+ list_for_each_entry_safe(item, n, &array->list, list) {
+ if (xfbma_is_null(array, item + 1))
+ goto next;
+ memcpy(array + 1, item + 1, array->obj_size);
+ error = iter_fn(array + 1, priv);
+ if (error)
+ break;
+next:
+ list_del(&item->list);
+ kmem_free(item);
+ array->nr--;
+ }
+
+ xfbma_cache_invalidate(array);
+ return error;
+}
+
+/* Return length of array. */
+uint64_t
+xfbma_length(
+ struct xfbma *array)
+{
+ return array->nr;
+}
+
+static int
+xfbma_item_cmp(
+ void *priv,
+ struct list_head *a,
+ struct list_head *b)
+{
+ int (*cmp_fn)(void *a, void *b) = priv;
+ struct xa_item *ai, *bi;
+
+ ai = container_of(a, struct xa_item, list);
+ bi = container_of(b, struct xa_item, list);
+
+ return cmp_fn(ai + 1, bi + 1);
+}
+
+/* Sort everything in this array. */
+int
+xfbma_sort(
+ struct xfbma *array,
+ xfbma_cmp_fn cmp_fn)
+{
+ list_sort(cmp_fn, &array->list, xfbma_item_cmp);
+ return 0;
+}
diff --git a/fs/xfs/scrub/array.h b/fs/xfs/scrub/array.h
new file mode 100644
index 000000000000..a6a7b69dc138
--- /dev/null
+++ b/fs/xfs/scrub/array.h
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ */
+#ifndef __XFS_SCRUB_ARRAY_H__
+#define __XFS_SCRUB_ARRAY_H__
+
+struct xma_item;
+
+struct xma_cache {
+ uint64_t nr;
+ struct xa_item *item;
+};
+
+#define XMA_CACHE_SIZE (8)
+
+struct xfbma {
+ struct list_head list;
+ size_t obj_size;
+ uint64_t nr;
+ struct xma_cache cache[XMA_CACHE_SIZE];
+};
+
+struct xfbma *xfbma_init(size_t obj_size);
+void xfbma_destroy(struct xfbma *array);
+int xfbma_get(struct xfbma *array, uint64_t nr, void *ptr);
+int xfbma_set(struct xfbma *array, uint64_t nr, void *ptr);
+int xfbma_insert_anywhere(struct xfbma *array, void *ptr);
+bool xfbma_is_null(struct xfbma *array, void *ptr);
+int xfbma_nullify(struct xfbma *array, uint64_t nr);
+int xfbma_append(struct xfbma *array, void *ptr);
+uint64_t xfbma_length(struct xfbma *array);
+
+/*
+ * Iterator functions return zero for success, a negative error code to abort
+ * with an error, or XFBMA_ITERATE_ABORT to stop iterating.
+ */
+#define XFBMA_ITERATE_ABORT (1)
+typedef int (*xfbma_iter_fn)(const void *item, void *priv);
+
+int xfbma_iter_del(struct xfbma *array, xfbma_iter_fn iter_fn, void *priv);
+
+typedef int (*xfbma_cmp_fn)(const void *a, const void *b);
+
+int xfbma_sort(struct xfbma *array, xfbma_cmp_fn cmp_fn);
+
+#define foreach_xfbma_item(array, i, rec) \
+ for ((i) = 0; (i) < xfbma_length(array); (i)++) \
+ if (xfbma_get((array), (i), &(rec)) == 0 && \
+ !xfbma_is_null((array), &(rec)))
+
+#endif /* __XFS_SCRUB_ARRAY_H__ */
