Btrfs: Optimizations for the extent_buffer code
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f60920e..9427b79 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -464,22 +464,12 @@
int level)
{
struct extent_buffer *buf = path->nodes[level];
- char fsid[BTRFS_FSID_SIZE];
- read_extent_buffer(buf, fsid, (unsigned long)btrfs_header_fsid(buf),
- BTRFS_FSID_SIZE);
-
- if (memcmp(fsid, root->fs_info->fsid, BTRFS_FSID_SIZE)) {
- int i = 0;
+ if (memcmp_extent_buffer(buf, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(buf),
+ BTRFS_FSID_SIZE)) {
printk("warning bad block %Lu\n", buf->start);
- if (!btrfs_buffer_uptodate(buf)) {
- WARN_ON(1);
- }
- for (i = 0; i < BTRFS_FSID_SIZE; i++) {
- printk("%x:%x ", root->fs_info->fsid[i], fsid[i]);
- }
- printk("\n");
- // BUG();
+ BUG();
}
if (level == 0)
return check_leaf(root, path, level);
@@ -504,13 +494,14 @@
int high = max;
int mid;
int ret;
- struct btrfs_disk_key *tmp;
+ struct btrfs_disk_key *tmp = NULL;
struct btrfs_disk_key unaligned;
unsigned long offset;
char *map_token = NULL;
char *kaddr = NULL;
unsigned long map_start = 0;
unsigned long map_len = 0;
+ int err;
while(low < high) {
mid = (low + high) / 2;
@@ -519,19 +510,24 @@
if (!map_token || offset < map_start ||
(offset + sizeof(struct btrfs_disk_key)) >
map_start + map_len) {
- if (map_token)
+ if (map_token) {
unmap_extent_buffer(eb, map_token, KM_USER0);
- map_extent_buffer(eb, offset, &map_token, &kaddr,
- &map_start, &map_len, KM_USER0);
+ map_token = NULL;
+ }
+ err = map_extent_buffer(eb, offset,
+ sizeof(struct btrfs_disk_key),
+ &map_token, &kaddr,
+ &map_start, &map_len, KM_USER0);
- }
- if (offset + sizeof(struct btrfs_disk_key) >
- map_start + map_len) {
- unmap_extent_buffer(eb, map_token, KM_USER0);
- read_extent_buffer(eb, &unaligned,
- offset, sizeof(unaligned));
- map_token = NULL;
- tmp = &unaligned;
+ if (!err) {
+ tmp = (struct btrfs_disk_key *)(kaddr + offset -
+ map_start);
+ } else {
+ read_extent_buffer(eb, &unaligned,
+ offset, sizeof(unaligned));
+ tmp = &unaligned;
+ }
+
} else {
tmp = (struct btrfs_disk_key *)(kaddr + offset -
map_start);
@@ -544,7 +540,8 @@
high = mid;
else {
*slot = mid;
- unmap_extent_buffer(eb, map_token, KM_USER0);
+ if (map_token)
+ unmap_extent_buffer(eb, map_token, KM_USER0);
return 0;
}
}
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index c4b8298..30fbbd7 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -22,6 +22,7 @@
#include <linux/fs.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
+#include <asm/kmap_types.h>
#include "bit-radix.h"
#include "extent_map.h"
@@ -431,15 +432,52 @@
static inline u##bits btrfs_##name(struct extent_buffer *eb, \
type *s) \
{ \
- __le##bits res; \
- read_eb_member(eb, s, type, member, &res); \
- return le##bits##_to_cpu(res); \
+ int err; \
+ char *map_token; \
+ char *kaddr; \
+ unsigned long map_start; \
+ unsigned long map_len; \
+ unsigned long offset = (unsigned long)s + \
+ offsetof(type, member); \
+ err = map_extent_buffer(eb, offset, \
+ sizeof(((type *)0)->member), \
+ &map_token, &kaddr, \
+ &map_start, &map_len, KM_USER0); \
+ if (!err) { \
+ __le##bits *tmp = (__le##bits *)(kaddr + offset - \
+ map_start); \
+ u##bits res = le##bits##_to_cpu(*tmp); \
+ unmap_extent_buffer(eb, map_token, KM_USER0); \
+ return res; \
+ } else { \
+ __le##bits res; \
+ read_eb_member(eb, s, type, member, &res); \
+ return le##bits##_to_cpu(res); \
+ } \
} \
static inline void btrfs_set_##name(struct extent_buffer *eb, \
type *s, u##bits val) \
{ \
- val = cpu_to_le##bits(val); \
- write_eb_member(eb, s, type, member, &val); \
+ int err; \
+ char *map_token; \
+ char *kaddr; \
+ unsigned long map_start; \
+ unsigned long map_len; \
+ unsigned long offset = (unsigned long)s + \
+ offsetof(type, member); \
+ err = map_extent_buffer(eb, offset, \
+ sizeof(((type *)0)->member), \
+ &map_token, &kaddr, \
+ &map_start, &map_len, KM_USER0); \
+ if (!err) { \
+ __le##bits *tmp = (__le##bits *)(kaddr + offset - \
+ map_start); \
+ *tmp = cpu_to_le##bits(val); \
+ unmap_extent_buffer(eb, map_token, KM_USER0); \
+ } else { \
+ val = cpu_to_le##bits(val); \
+ write_eb_member(eb, s, type, member, &val); \
+ } \
}
#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits) \
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 55fefdf..8bef309 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -2140,14 +2140,20 @@
EXPORT_SYMBOL(read_extent_buffer);
int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
+ unsigned long min_len,
char **token, char **map,
unsigned long *map_start,
unsigned long *map_len, int km)
{
- size_t offset;
+ size_t offset = start & (PAGE_CACHE_SIZE - 1);
char *kaddr;
size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+ unsigned long end_i = (start_offset + start + min_len) >>
+ PAGE_CACHE_SHIFT;
+
+ if (i != end_i)
+ return -EINVAL;
WARN_ON(start > eb->len);
@@ -2155,8 +2161,7 @@
offset = start_offset;
*map_start = 0;
} else {
- offset = 0;
- *map_start = (i << PAGE_CACHE_SHIFT) - offset;
+ *map_start = (i << PAGE_CACHE_SHIFT) - start_offset;
}
// kaddr = kmap_atomic(eb->pages[i], km);
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 430b997..8957890 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -173,7 +173,7 @@
int extent_buffer_uptodate(struct extent_map_tree *tree,
struct extent_buffer *eb);
int map_extent_buffer(struct extent_buffer *eb, unsigned long offset,
- char **token, char **map,
+ unsigned long min_len, char **token, char **map,
unsigned long *map_start,
unsigned long *map_len, int km);
void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km);