1 files changed, 351 insertions, 0 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
new file mode 100644
index 000000000000..4a83e33ada32
--- /dev/null
+++ b/fs/btrfs/extent_map.c
@@ -0,0 +1,351 @@
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/version.h>
+#include <linux/hardirq.h>
+#include "extent_map.h"
+/* temporary define until extent_map moves out of btrfs */
+struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
+                                       unsigned long extra_flags,
+                                       void (*ctor)(void *, struct kmem_cache *,
+                                                    unsigned long));
+static struct kmem_cache *extent_map_cache;
+int __init extent_map_init(void)
+{
+        extent_map_cache = btrfs_cache_create("extent_map",
+                                            sizeof(struct extent_map), 0,
+                                            NULL);
+        if (!extent_map_cache)
+                return -ENOMEM;
+        return 0;
+}
+void extent_map_exit(void)
+{
+        if (extent_map_cache)
+                kmem_cache_destroy(extent_map_cache);
+}
+/**
+ * extent_map_tree_init - initialize extent map tree
+ * @tree:               tree to initialize
+ * @mask:               flags for memory allocations during tree operations
+ *
+ * Initialize the extent tree @tree.  Should be called for each new inode
+ * or other user of the extent_map interface.
+ */
+void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
+{
+        tree->map.rb_node = NULL;
+        spin_lock_init(&tree->lock);
+}
+EXPORT_SYMBOL(extent_map_tree_init);
+/**
+ * alloc_extent_map - allocate new extent map structure
+ * @mask:       memory allocation flags
+ *
+ * Allocate a new extent_map structure.  The new structure is
+ * returned with a reference count of one and needs to be
+ * freed using free_extent_map()
+ */
+struct extent_map *alloc_extent_map(gfp_t mask)
+{
+        struct extent_map *em;
+        em = kmem_cache_alloc(extent_map_cache, mask);
+        if (!em || IS_ERR(em))
+                return em;
+        em->in_tree = 0;
+        em->flags = 0;
+        atomic_set(&em->refs, 1);
+        return em;
+}
+EXPORT_SYMBOL(alloc_extent_map);
+/**
+ * free_extent_map - drop reference count of an extent_map
+ * @em:         extent map beeing releasead
+ *
+ * Drops the reference out on @em by one and free the structure
+ * if the reference count hits zero.
+ */
+void free_extent_map(struct extent_map *em)
+{
+        if (!em)
+                return;
+        WARN_ON(atomic_read(&em->refs) == 0);
+        if (atomic_dec_and_test(&em->refs)) {
+                WARN_ON(em->in_tree);
+                kmem_cache_free(extent_map_cache, em);
+        }
+}
+EXPORT_SYMBOL(free_extent_map);
+static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
+                                   struct rb_node *node)
+{
+        struct rb_node **p = &root->rb_node;
+        struct rb_node *parent = NULL;
+        struct extent_map *entry;
+        while (*p) {
+                parent = *p;
+                entry = rb_entry(parent, struct extent_map, rb_node);
+                WARN_ON(!entry->in_tree);
+                if (offset < entry->start)
+                        p = &(*p)->rb_left;
+                else if (offset >= extent_map_end(entry))
+                        p = &(*p)->rb_right;
+                else
+                        return parent;
+        }
+        entry = rb_entry(node, struct extent_map, rb_node);
+        entry->in_tree = 1;
+        rb_link_node(node, parent, p);
+        rb_insert_color(node, root);
+        return NULL;
+}
+/*
+ * search through the tree for an extent_map with a given offset.  If
+ * it can't be found, try to find some neighboring extents
+ */
+static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
+                                     struct rb_node **prev_ret,
+                                     struct rb_node **next_ret)
+{
+        struct rb_node *n = root->rb_node;
+        struct rb_node *prev = NULL;
+        struct rb_node *orig_prev = NULL;
+        struct extent_map *entry;
+        struct extent_map *prev_entry = NULL;
+        while (n) {
+                entry = rb_entry(n, struct extent_map, rb_node);
+                prev = n;
+                prev_entry = entry;
+                WARN_ON(!entry->in_tree);
+                if (offset < entry->start)
+                        n = n->rb_left;
+                else if (offset >= extent_map_end(entry))
+                        n = n->rb_right;
+                else
+                        return n;
+        }
+        if (prev_ret) {
+                orig_prev = prev;
+                while (prev && offset >= extent_map_end(prev_entry)) {
+                        prev = rb_next(prev);
+                        prev_entry = rb_entry(prev, struct extent_map, rb_node);
+                }
+                *prev_ret = prev;
+                prev = orig_prev;
+        }
+        if (next_ret) {
+                prev_entry = rb_entry(prev, struct extent_map, rb_node);
+                while (prev && offset < prev_entry->start) {
+                        prev = rb_prev(prev);
+                        prev_entry = rb_entry(prev, struct extent_map, rb_node);
+                }
+                *next_ret = prev;
+        }
+        return NULL;
+}
+/*
+ * look for an offset in the tree, and if it can't be found, return
+ * the first offset we can find smaller than 'offset'.
+ */
+static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
+{
+        struct rb_node *prev;
+        struct rb_node *ret;
+        ret = __tree_search(root, offset, &prev, NULL);
+        if (!ret)
+                return prev;
+        return ret;
+}
+/* check to see if two extent_map structs are adjacent and safe to merge */
+static int mergable_maps(struct extent_map *prev, struct extent_map *next)
+{
+        if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
+                return 0;
+        /*
+         * don't merge compressed extents, we need to know their
+         * actual size
+         */
+        if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
+                return 0;
+        if (extent_map_end(prev) == next->start &&
+            prev->flags == next->flags &&
+            prev->bdev == next->bdev &&
+            ((next->block_start == EXTENT_MAP_HOLE &&
+              prev->block_start == EXTENT_MAP_HOLE) ||
+             (next->block_start == EXTENT_MAP_INLINE &&
+              prev->block_start == EXTENT_MAP_INLINE) ||
+             (next->block_start == EXTENT_MAP_DELALLOC &&
+              prev->block_start == EXTENT_MAP_DELALLOC) ||
+             (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
+              next->block_start == extent_map_block_end(prev)))) {
+                return 1;
+        }
+        return 0;
+}
+/**
+ * add_extent_mapping - add new extent map to the extent tree
+ * @tree:       tree to insert new map in
+ * @em:         map to insert
+ *
+ * Insert @em into @tree or perform a simple forward/backward merge with
+ * existing mappings.  The extent_map struct passed in will be inserted
+ * into the tree directly, with an additional reference taken, or a
+ * reference dropped if the merge attempt was sucessfull.
+ */
+int add_extent_mapping(struct extent_map_tree *tree,
+                       struct extent_map *em)
+{
+        int ret = 0;
+        struct extent_map *merge = NULL;
+        struct rb_node *rb;
+        struct extent_map *exist;
+        exist = lookup_extent_mapping(tree, em->start, em->len);
+        if (exist) {
+                free_extent_map(exist);
+                ret = -EEXIST;
+                goto out;
+        }
+        assert_spin_locked(&tree->lock);
+        rb = tree_insert(&tree->map, em->start, &em->rb_node);
+        if (rb) {
+                ret = -EEXIST;
+                free_extent_map(merge);
+                goto out;
+        }
+        atomic_inc(&em->refs);
+        if (em->start != 0) {
+                rb = rb_prev(&em->rb_node);
+                if (rb)
+                        merge = rb_entry(rb, struct extent_map, rb_node);
+                if (rb && mergable_maps(merge, em)) {
+                        em->start = merge->start;
+                        em->len += merge->len;
+                        em->block_len += merge->block_len;
+                        em->block_start = merge->block_start;
+                        merge->in_tree = 0;
+                        rb_erase(&merge->rb_node, &tree->map);
+                        free_extent_map(merge);
+                }
+         }
+        rb = rb_next(&em->rb_node);
+        if (rb)
+                merge = rb_entry(rb, struct extent_map, rb_node);
+        if (rb && mergable_maps(em, merge)) {
+                em->len += merge->len;
+                em->block_len += merge->len;
+                rb_erase(&merge->rb_node, &tree->map);
+                merge->in_tree = 0;
+                free_extent_map(merge);
+        }
+out:
+        return ret;
+}
+EXPORT_SYMBOL(add_extent_mapping);
+/* simple helper to do math around the end of an extent, handling wrap */
+static u64 range_end(u64 start, u64 len)
+{
+        if (start + len < start)
+                return (u64)-1;
+        return start + len;
+}
+/**
+ * lookup_extent_mapping - lookup extent_map
+ * @tree:       tree to lookup in
+ * @start:      byte offset to start the search
+ * @len:        length of the lookup range
+ *
+ * Find and return the first extent_map struct in @tree that intersects the
+ * [start, len] range.  There may be additional objects in the tree that
+ * intersect, so check the object returned carefully to make sure that no
+ * additional lookups are needed.
+ */
+struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
+                                         u64 start, u64 len)
+{
+        struct extent_map *em;
+        struct rb_node *rb_node;
+        struct rb_node *prev = NULL;
+        struct rb_node *next = NULL;
+        u64 end = range_end(start, len);
+        assert_spin_locked(&tree->lock);
+        rb_node = __tree_search(&tree->map, start, &prev, &next);
+        if (!rb_node && prev) {
+                em = rb_entry(prev, struct extent_map, rb_node);
+                if (end > em->start && start < extent_map_end(em))
+                        goto found;
+        }
+        if (!rb_node && next) {
+                em = rb_entry(next, struct extent_map, rb_node);
+                if (end > em->start && start < extent_map_end(em))
+                        goto found;
+        }
+        if (!rb_node) {
+                em = NULL;
+                goto out;
+        }
+        if (IS_ERR(rb_node)) {
+                em = ERR_PTR(PTR_ERR(rb_node));
+                goto out;
+        }
+        em = rb_entry(rb_node, struct extent_map, rb_node);
+        if (end > em->start && start < extent_map_end(em))
+                goto found;
+        em = NULL;
+        goto out;
+found:
+        atomic_inc(&em->refs);
+out:
+        return em;
+}
+EXPORT_SYMBOL(lookup_extent_mapping);
+/**
+ * remove_extent_mapping - removes an extent_map from the extent tree
+ * @tree:       extent tree to remove from
+ * @em:         extent map beeing removed
+ *
+ * Removes @em from @tree.  No reference counts are dropped, and no checks
+ * are done to see if the range is in use
+ */
+int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
+{
+        int ret = 0;
+        WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
+        assert_spin_locked(&tree->lock);
+        rb_erase(&em->rb_node, &tree->map);
+        em->in_tree = 0;
+        return ret;
+}
+EXPORT_SYMBOL(remove_extent_mapping);

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c new file mode 100644 index 000000000000..4a83e33ada32 --- /dev/null +++ b/fs/btrfs/extent_map.c
@@ -0,0 +1,351 @@
	1	#include <linux/err.h>
	2	#include <linux/gfp.h>
	3	#include <linux/slab.h>
	4	#include <linux/module.h>
	5	#include <linux/spinlock.h>
	6	#include <linux/version.h>
	7	#include <linux/hardirq.h>
	8	#include "extent_map.h"
	9
	10	/* temporary define until extent_map moves out of btrfs */
	11	struct kmem_cache btrfs_cache_create(const char name, size_t size,
	12	unsigned long extra_flags,
	13	void (ctor)(void , struct kmem_cache *,
	14	unsigned long));
	15
	16	static struct kmem_cache *extent_map_cache;
	17
	18	int __init extent_map_init(void)
	19	{
	20	extent_map_cache = btrfs_cache_create("extent_map",
	21	sizeof(struct extent_map), 0,
	22	NULL);
	23	if (!extent_map_cache)
	24	return -ENOMEM;
	25	return 0;
	26	}
	27
	28	void extent_map_exit(void)
	29	{
	30	if (extent_map_cache)
	31	kmem_cache_destroy(extent_map_cache);
	32	}
	33
	34	/**
	35	* extent_map_tree_init - initialize extent map tree
	36	* @tree: tree to initialize
	37	* @mask: flags for memory allocations during tree operations
	38	*
	39	* Initialize the extent tree @tree. Should be called for each new inode
	40	* or other user of the extent_map interface.
	41	*/
	42	void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
	43	{
	44	tree->map.rb_node = NULL;
	45	spin_lock_init(&tree->lock);
	46	}
	47	EXPORT_SYMBOL(extent_map_tree_init);
	48
	49	/**
	50	* alloc_extent_map - allocate new extent map structure
	51	* @mask: memory allocation flags
	52	*
	53	* Allocate a new extent_map structure. The new structure is
	54	* returned with a reference count of one and needs to be
	55	* freed using free_extent_map()
	56	*/
	57	struct extent_map *alloc_extent_map(gfp_t mask)
	58	{
	59	struct extent_map *em;
	60	em = kmem_cache_alloc(extent_map_cache, mask);
	61	if (!em \|\| IS_ERR(em))
	62	return em;
	63	em->in_tree = 0;
	64	em->flags = 0;
	65	atomic_set(&em->refs, 1);
	66	return em;
	67	}
	68	EXPORT_SYMBOL(alloc_extent_map);
	69
	70	/**
	71	* free_extent_map - drop reference count of an extent_map
	72	* @em: extent map beeing releasead
	73	*
	74	* Drops the reference out on @em by one and free the structure
	75	* if the reference count hits zero.
	76	*/
	77	void free_extent_map(struct extent_map *em)
	78	{
	79	if (!em)
	80	return;
	81	WARN_ON(atomic_read(&em->refs) == 0);
	82	if (atomic_dec_and_test(&em->refs)) {
	83	WARN_ON(em->in_tree);
	84	kmem_cache_free(extent_map_cache, em);
	85	}
	86	}
	87	EXPORT_SYMBOL(free_extent_map);
	88
	89	static struct rb_node tree_insert(struct rb_root root, u64 offset,
	90	struct rb_node *node)
	91	{
	92	struct rb_node **p = &root->rb_node;
	93	struct rb_node *parent = NULL;
	94	struct extent_map *entry;
	95
	96	while (*p) {
	97	parent = *p;
	98	entry = rb_entry(parent, struct extent_map, rb_node);
	99
	100	WARN_ON(!entry->in_tree);
	101
	102	if (offset < entry->start)
	103	p = &(*p)->rb_left;
	104	else if (offset >= extent_map_end(entry))
	105	p = &(*p)->rb_right;
	106	else
	107	return parent;
	108	}
	109
	110	entry = rb_entry(node, struct extent_map, rb_node);
	111	entry->in_tree = 1;
	112	rb_link_node(node, parent, p);
	113	rb_insert_color(node, root);
	114	return NULL;
	115	}
	116
	117	/*
	118	* search through the tree for an extent_map with a given offset. If
	119	* it can't be found, try to find some neighboring extents
	120	*/
	121	static struct rb_node __tree_search(struct rb_root root, u64 offset,
	122	struct rb_node **prev_ret,
	123	struct rb_node **next_ret)
	124	{
	125	struct rb_node *n = root->rb_node;
	126	struct rb_node *prev = NULL;
	127	struct rb_node *orig_prev = NULL;
	128	struct extent_map *entry;
	129	struct extent_map *prev_entry = NULL;
	130
	131	while (n) {
	132	entry = rb_entry(n, struct extent_map, rb_node);
	133	prev = n;
	134	prev_entry = entry;
	135
	136	WARN_ON(!entry->in_tree);
	137
	138	if (offset < entry->start)
	139	n = n->rb_left;
	140	else if (offset >= extent_map_end(entry))
	141	n = n->rb_right;
	142	else
	143	return n;
	144	}
	145
	146	if (prev_ret) {
	147	orig_prev = prev;
	148	while (prev && offset >= extent_map_end(prev_entry)) {
	149	prev = rb_next(prev);
	150	prev_entry = rb_entry(prev, struct extent_map, rb_node);
	151	}
	152	*prev_ret = prev;
	153	prev = orig_prev;
	154	}
	155
	156	if (next_ret) {
	157	prev_entry = rb_entry(prev, struct extent_map, rb_node);
	158	while (prev && offset < prev_entry->start) {
	159	prev = rb_prev(prev);
	160	prev_entry = rb_entry(prev, struct extent_map, rb_node);
	161	}
	162	*next_ret = prev;
	163	}
	164	return NULL;
	165	}
	166
	167	/*
	168	* look for an offset in the tree, and if it can't be found, return
	169	* the first offset we can find smaller than 'offset'.
	170	*/
	171	static inline struct rb_node tree_search(struct rb_root root, u64 offset)
	172	{
	173	struct rb_node *prev;
	174	struct rb_node *ret;
	175	ret = __tree_search(root, offset, &prev, NULL);
	176	if (!ret)
	177	return prev;
	178	return ret;
	179	}
	180
	181	/* check to see if two extent_map structs are adjacent and safe to merge */
	182	static int mergable_maps(struct extent_map prev, struct extent_map next)
	183	{
	184	if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
	185	return 0;
	186
	187	/*
	188	* don't merge compressed extents, we need to know their
	189	* actual size
	190	*/
	191	if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
	192	return 0;
	193
	194	if (extent_map_end(prev) == next->start &&
	195	prev->flags == next->flags &&
	196	prev->bdev == next->bdev &&
	197	((next->block_start == EXTENT_MAP_HOLE &&
	198	prev->block_start == EXTENT_MAP_HOLE) \|\|
	199	(next->block_start == EXTENT_MAP_INLINE &&
	200	prev->block_start == EXTENT_MAP_INLINE) \|\|
	201	(next->block_start == EXTENT_MAP_DELALLOC &&
	202	prev->block_start == EXTENT_MAP_DELALLOC) \|\|
	203	(next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
	204	next->block_start == extent_map_block_end(prev)))) {
	205	return 1;
	206	}
	207	return 0;
	208	}
	209
	210	/**
	211	* add_extent_mapping - add new extent map to the extent tree
	212	* @tree: tree to insert new map in
	213	* @em: map to insert
	214	*
	215	* Insert @em into @tree or perform a simple forward/backward merge with
	216	* existing mappings. The extent_map struct passed in will be inserted
	217	* into the tree directly, with an additional reference taken, or a
	218	* reference dropped if the merge attempt was sucessfull.
	219	*/
	220	int add_extent_mapping(struct extent_map_tree *tree,
	221	struct extent_map *em)
	222	{
	223	int ret = 0;
	224	struct extent_map *merge = NULL;
	225	struct rb_node *rb;
	226	struct extent_map *exist;
	227
	228	exist = lookup_extent_mapping(tree, em->start, em->len);
	229	if (exist) {
	230	free_extent_map(exist);
	231	ret = -EEXIST;
	232	goto out;
	233	}
	234	assert_spin_locked(&tree->lock);
	235	rb = tree_insert(&tree->map, em->start, &em->rb_node);
	236	if (rb) {
	237	ret = -EEXIST;
	238	free_extent_map(merge);
	239	goto out;
	240	}
	241	atomic_inc(&em->refs);
	242	if (em->start != 0) {
	243	rb = rb_prev(&em->rb_node);
	244	if (rb)
	245	merge = rb_entry(rb, struct extent_map, rb_node);
	246	if (rb && mergable_maps(merge, em)) {
	247	em->start = merge->start;
	248	em->len += merge->len;
	249	em->block_len += merge->block_len;
	250	em->block_start = merge->block_start;
	251	merge->in_tree = 0;
	252	rb_erase(&merge->rb_node, &tree->map);
	253	free_extent_map(merge);
	254	}
	255	}
	256	rb = rb_next(&em->rb_node);
	257	if (rb)
	258	merge = rb_entry(rb, struct extent_map, rb_node);
	259	if (rb && mergable_maps(em, merge)) {
	260	em->len += merge->len;
	261	em->block_len += merge->len;
	262	rb_erase(&merge->rb_node, &tree->map);
	263	merge->in_tree = 0;
	264	free_extent_map(merge);
	265	}
	266	out:
	267	return ret;
	268	}
	269	EXPORT_SYMBOL(add_extent_mapping);
	270
	271	/* simple helper to do math around the end of an extent, handling wrap */
	272	static u64 range_end(u64 start, u64 len)
	273	{
	274	if (start + len < start)
	275	return (u64)-1;
	276	return start + len;
	277	}
	278
	279	/**
	280	* lookup_extent_mapping - lookup extent_map
	281	* @tree: tree to lookup in
	282	* @start: byte offset to start the search
	283	* @len: length of the lookup range
	284	*
	285	* Find and return the first extent_map struct in @tree that intersects the
	286	* [start, len] range. There may be additional objects in the tree that
	287	* intersect, so check the object returned carefully to make sure that no
	288	* additional lookups are needed.
	289	*/
	290	struct extent_map lookup_extent_mapping(struct extent_map_tree tree,
	291	u64 start, u64 len)
	292	{
	293	struct extent_map *em;
	294	struct rb_node *rb_node;
	295	struct rb_node *prev = NULL;
	296	struct rb_node *next = NULL;
	297	u64 end = range_end(start, len);
	298
	299	assert_spin_locked(&tree->lock);
	300	rb_node = __tree_search(&tree->map, start, &prev, &next);
	301	if (!rb_node && prev) {
	302	em = rb_entry(prev, struct extent_map, rb_node);
	303	if (end > em->start && start < extent_map_end(em))
	304	goto found;
	305	}
	306	if (!rb_node && next) {
	307	em = rb_entry(next, struct extent_map, rb_node);
	308	if (end > em->start && start < extent_map_end(em))
	309	goto found;
	310	}
	311	if (!rb_node) {
	312	em = NULL;
	313	goto out;
	314	}
	315	if (IS_ERR(rb_node)) {
	316	em = ERR_PTR(PTR_ERR(rb_node));
	317	goto out;
	318	}
	319	em = rb_entry(rb_node, struct extent_map, rb_node);
	320	if (end > em->start && start < extent_map_end(em))
	321	goto found;
	322
	323	em = NULL;
	324	goto out;
	325
	326	found:
	327	atomic_inc(&em->refs);
	328	out:
	329	return em;
	330	}
	331	EXPORT_SYMBOL(lookup_extent_mapping);
	332
	333	/**
	334	* remove_extent_mapping - removes an extent_map from the extent tree
	335	* @tree: extent tree to remove from
	336	* @em: extent map beeing removed
	337	*
	338	* Removes @em from @tree. No reference counts are dropped, and no checks
	339	* are done to see if the range is in use
	340	*/
	341	int remove_extent_mapping(struct extent_map_tree tree, struct extent_map em)
	342	{
	343	int ret = 0;
	344
	345	WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
	346	assert_spin_locked(&tree->lock);
	347	rb_erase(&em->rb_node, &tree->map);
	348	em->in_tree = 0;
	349	return ret;
	350	}
	351	EXPORT_SYMBOL(remove_extent_mapping);