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Btrfs: unaligned access fixes
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Btrfs set/get macros lose type information needed to avoid
unaligned accesses on sparc64.
ere is a patch for the kernel bits which fixes most of the
unaligned accesses on sparc64.

btrfs_name_hash is modified to return the hash value instead
of getting a return location via a (potentially unaligned)
pointer.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
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David Miller authored and Chris Mason committed Sep 25, 2008
1 parent 39b5637 commit df68b8a
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Showing 5 changed files with 33 additions and 45 deletions.
17 changes: 6 additions & 11 deletions fs/btrfs/ctree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -495,22 +495,17 @@ void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val);
#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits) \
static inline u##bits btrfs_##name(struct extent_buffer *eb) \
{ \
char *kaddr = kmap_atomic(eb->first_page, KM_USER0); \
unsigned long offset = offsetof(type, member); \
u##bits res; \
__le##bits *tmp = (__le##bits *)(kaddr + offset); \
res = le##bits##_to_cpu(*tmp); \
kunmap_atomic(kaddr, KM_USER0); \
type *p = kmap_atomic(eb->first_page, KM_USER0); \
u##bits res = le##bits##_to_cpu(p->member); \
kunmap_atomic(p, KM_USER0); \
return res; \
} \
static inline void btrfs_set_##name(struct extent_buffer *eb, \
u##bits val) \
{ \
char *kaddr = kmap_atomic(eb->first_page, KM_USER0); \
unsigned long offset = offsetof(type, member); \
__le##bits *tmp = (__le##bits *)(kaddr + offset); \
*tmp = cpu_to_le##bits(val); \
kunmap_atomic(kaddr, KM_USER0); \
type *p = kmap_atomic(eb->first_page, KM_USER0); \
p->member = cpu_to_le##bits(val); \
kunmap_atomic(p, KM_USER0); \
}

#define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits) \
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12 changes: 4 additions & 8 deletions fs/btrfs/dir-item.c
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Original file line number Diff line number Diff line change
Expand Up @@ -71,8 +71,7 @@ int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,

key.objectid = dir;
btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
ret = btrfs_name_hash(name, name_len, &key.offset);
BUG_ON(ret);
key.offset = btrfs_name_hash(name, name_len);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
Expand Down Expand Up @@ -125,8 +124,7 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root

key.objectid = dir;
btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
ret = btrfs_name_hash(name, name_len, &key.offset);
BUG_ON(ret);
key.offset = btrfs_name_hash(name, name_len);
path = btrfs_alloc_path();
data_size = sizeof(*dir_item) + name_len;
dir_item = insert_with_overflow(trans, root, path, &key, data_size,
Expand Down Expand Up @@ -199,8 +197,7 @@ struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
key.objectid = dir;
btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);

ret = btrfs_name_hash(name, name_len, &key.offset);
BUG_ON(ret);
key.offset = btrfs_name_hash(name, name_len);

ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
if (ret < 0)
Expand Down Expand Up @@ -261,8 +258,7 @@ struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,

key.objectid = dir;
btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
ret = btrfs_name_hash(name, name_len, &key.offset);
BUG_ON(ret);
key.offset = btrfs_name_hash(name, name_len);
ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
if (ret < 0)
return ERR_PTR(ret);
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17 changes: 8 additions & 9 deletions fs/btrfs/hash.c
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Original file line number Diff line number Diff line change
Expand Up @@ -76,19 +76,18 @@ static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
*buf++ = pad;
}

int btrfs_name_hash(const char *name, int len, u64 *hash_result)
u64 btrfs_name_hash(const char *name, int len)
{
__u32 hash;
__u32 minor_hash = 0;
const char *p;
__u32 in[8], buf[2];
u64 hash_result;

if (len == 1 && *name == '.') {
*hash_result = 1;
return 0;
return 1;
} else if (len == 2 && name[0] == '.' && name[1] == '.') {
*hash_result = 2;
return 0;
return 2;
}

/* Initialize the default seed for the hash checksum functions */
Expand All @@ -106,8 +105,8 @@ int btrfs_name_hash(const char *name, int len, u64 *hash_result)
}
hash = buf[0];
minor_hash = buf[1];
*hash_result = buf[0];
*hash_result <<= 32;
*hash_result |= buf[1];
return 0;
hash_result = buf[0];
hash_result <<= 32;
hash_result |= buf[1];
return hash_result;
}
2 changes: 1 addition & 1 deletion fs/btrfs/hash.h
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Original file line number Diff line number Diff line change
Expand Up @@ -18,5 +18,5 @@

#ifndef __HASH__
#define __HASH__
int btrfs_name_hash(const char *name, int len, u64 *hash_result);
u64 btrfs_name_hash(const char *name, int len);
#endif
30 changes: 14 additions & 16 deletions fs/btrfs/struct-funcs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,16 +21,15 @@
u##bits btrfs_##name(struct extent_buffer *eb, \
type *s) \
{ \
unsigned long offset = (unsigned long)s + \
offsetof(type, member); \
__le##bits *tmp; \
unsigned long part_offset = (unsigned long)s; \
unsigned long offset = part_offset + offsetof(type, member); \
type *p; \
/* ugly, but we want the fast path here */ \
if (eb->map_token && offset >= eb->map_start && \
offset + sizeof(((type *)0)->member) <= eb->map_start + \
eb->map_len) { \
tmp = (__le##bits *)(eb->kaddr + offset - \
eb->map_start); \
return le##bits##_to_cpu(*tmp); \
p = (type *)(eb->kaddr + part_offset - eb->map_start); \
return le##bits##_to_cpu(p->member); \
} \
{ \
int err; \
Expand All @@ -48,8 +47,8 @@ u##bits btrfs_##name(struct extent_buffer *eb, \
read_eb_member(eb, s, type, member, &res); \
return le##bits##_to_cpu(res); \
} \
tmp = (__le##bits *)(kaddr + offset - map_start); \
res = le##bits##_to_cpu(*tmp); \
p = (type *)(kaddr + part_offset - map_start); \
res = le##bits##_to_cpu(p->member); \
if (unmap_on_exit) \
unmap_extent_buffer(eb, map_token, KM_USER1); \
return res; \
Expand All @@ -58,16 +57,15 @@ u##bits btrfs_##name(struct extent_buffer *eb, \
void btrfs_set_##name(struct extent_buffer *eb, \
type *s, u##bits val) \
{ \
unsigned long offset = (unsigned long)s + \
offsetof(type, member); \
__le##bits *tmp; \
unsigned long part_offset = (unsigned long)s; \
unsigned long offset = part_offset + offsetof(type, member); \
type *p; \
/* ugly, but we want the fast path here */ \
if (eb->map_token && offset >= eb->map_start && \
offset + sizeof(((type *)0)->member) <= eb->map_start + \
eb->map_len) { \
tmp = (__le##bits *)(eb->kaddr + offset - \
eb->map_start); \
*tmp = cpu_to_le##bits(val); \
p = (type *)(eb->kaddr + part_offset - eb->map_start); \
p->member = cpu_to_le##bits(val); \
return; \
} \
{ \
Expand All @@ -86,8 +84,8 @@ void btrfs_set_##name(struct extent_buffer *eb, \
write_eb_member(eb, s, type, member, &val); \
return; \
} \
tmp = (__le##bits *)(kaddr + offset - map_start); \
*tmp = cpu_to_le##bits(val); \
p = (type *)(kaddr + part_offset - map_start); \
p->member = cpu_to_le##bits(val); \
if (unmap_on_exit) \
unmap_extent_buffer(eb, map_token, KM_USER1); \
} \
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