X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=fs%2Fbtrfs%2Fextent_map.c;h=50da69da20cec141fca63ffba2a4e92b8f93f875;hb=5d13a98f3bf5afc1113f7db184c627a44659bc29;hp=954b047639ab23aa5a0c732bff8ad79e4a64ece4;hpb=64f26f745084872b916cd1bef6054e21b15c5784;p=linux-2.6-omap-h63xx.git

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 954b047639a..50da69da20c 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -3,7 +3,6 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
-#include <linux/version.h>
 #include <linux/hardirq.h>
 #include "extent_map.h"
 
@@ -89,11 +88,11 @@ 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 rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
 	struct extent_map *entry;
 
-	while(*p) {
+	while (*p) {
 		parent = *p;
 		entry = rb_entry(parent, struct extent_map, rb_node);
 
@@ -114,17 +113,21 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
 	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 *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) {
+	while (n) {
 		entry = rb_entry(n, struct extent_map, rb_node);
 		prev = n;
 		prev_entry = entry;
@@ -141,7 +144,7 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
 
 	if (prev_ret) {
 		orig_prev = prev;
-		while(prev && offset >= extent_map_end(prev_entry)) {
+		while (prev && offset >= extent_map_end(prev_entry)) {
 			prev = rb_next(prev);
 			prev_entry = rb_entry(prev, struct extent_map, rb_node);
 		}
@@ -151,7 +154,7 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
 
 	if (next_ret) {
 		prev_entry = rb_entry(prev, struct extent_map, rb_node);
-		while(prev && offset < prev_entry->start) {
+		while (prev && offset < prev_entry->start) {
 			prev = rb_prev(prev);
 			prev_entry = rb_entry(prev, struct extent_map, rb_node);
 		}
@@ -160,6 +163,10 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
 	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;
@@ -170,11 +177,19 @@ static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
 	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 &&
@@ -207,7 +222,14 @@ int add_extent_mapping(struct extent_map_tree *tree,
 	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) {
@@ -223,6 +245,7 @@ int add_extent_mapping(struct extent_map_tree *tree,
 		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);
@@ -234,6 +257,7 @@ int add_extent_mapping(struct extent_map_tree *tree,
 		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);
@@ -243,6 +267,7 @@ out:
 }
 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)