Btrfs: unaligned access fixes

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>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 52144b0..086cb05 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -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)             \

diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index 5247a9a..7a73dc5 100644 (file)
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -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;
@@ -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,
@@ -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)
@@ -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);

diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
index e5c7690..d5252f5 100644 (file)
--- a/fs/btrfs/hash.c
+++ b/fs/btrfs/hash.c
@@ -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 */
@@ -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;
 }

diff --git a/fs/btrfs/hash.h b/fs/btrfs/hash.h
index d3be026..868ee17 100644 (file)
--- a/fs/btrfs/hash.h
+++ b/fs/btrfs/hash.h
@@ -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

diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index c5715a6..ad03a32 100644 (file)
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -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;                                                \
@@ -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;                                             \
@@ -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;                                                 \
        }                                                               \
        {                                                               \
@@ -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);   \
        }                                                               \