ocfs2: Refactor xattr list and remove ocfs2_xattr_handler().

According to Christoph Hellwig's advice, we really don't need
a ->list to handle one xattr's list. Just a map from index to
xattr prefix is enough. And I also refactor the old list method
with the reference from fs/xfs/linux-2.6/xfs_xattr.c and the
xattr list method in btrfs.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 092a123..8f522f2 100644 (file)
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -137,14 +137,14 @@ static int ocfs2_xattr_set_entry_index_block(struct inode *inode,
 static int ocfs2_delete_xattr_index_block(struct inode *inode,
                                          struct buffer_head *xb_bh);
 
-static inline struct xattr_handler *ocfs2_xattr_handler(int name_index)
+static inline const char *ocfs2_xattr_prefix(int name_index)
 {
        struct xattr_handler *handler = NULL;
 
        if (name_index > 0 && name_index < OCFS2_XATTR_MAX)
                handler = ocfs2_xattr_handler_map[name_index];
 
-       return handler;
+       return handler ? handler->prefix : NULL;
 }
 
 static u32 ocfs2_xattr_name_hash(struct inode *inode,
@@ -452,33 +452,56 @@ static int ocfs2_xattr_value_truncate(struct inode *inode,
        return ret;
 }
 
+static int ocfs2_xattr_list_entry(char *buffer, size_t size,
+                                 size_t *result, const char *prefix,
+                                 const char *name, int name_len)
+{
+       char *p = buffer + *result;
+       int prefix_len = strlen(prefix);
+       int total_len = prefix_len + name_len + 1;
+
+       *result += total_len;
+
+       /* we are just looking for how big our buffer needs to be */
+       if (!size)
+               return 0;
+
+       if (*result > size)
+               return -ERANGE;
+
+       memcpy(p, prefix, prefix_len);
+       memcpy(p + prefix_len, name, name_len);
+       p[prefix_len + name_len] = '\0';
+
+       return 0;
+}
+
 static int ocfs2_xattr_list_entries(struct inode *inode,
                                    struct ocfs2_xattr_header *header,
                                    char *buffer, size_t buffer_size)
 {
-       size_t rest = buffer_size;
-       int i;
+       size_t result = 0;
+       int i, type, ret;
+       const char *prefix, *name;
 
        for (i = 0 ; i < le16_to_cpu(header->xh_count); i++) {
                struct ocfs2_xattr_entry *entry = &header->xh_entries[i];
-               struct xattr_handler *handler =
-                       ocfs2_xattr_handler(ocfs2_xattr_get_type(entry));
-
-               if (handler) {
-                       size_t size = handler->list(inode, buffer, rest,
-                                       ((char *)header +
-                                       le16_to_cpu(entry->xe_name_offset)),
-                                       entry->xe_name_len);
-                       if (buffer) {
-                               if (size > rest)
-                                       return -ERANGE;
-                               buffer += size;
-                       }
-                       rest -= size;
+               type = ocfs2_xattr_get_type(entry);
+               prefix = ocfs2_xattr_prefix(type);
+
+               if (prefix) {
+                       name = (const char *)header +
+                               le16_to_cpu(entry->xe_name_offset);
+
+                       ret = ocfs2_xattr_list_entry(buffer, buffer_size,
+                                                    &result, prefix, name,
+                                                    entry->xe_name_len);
+                       if (ret)
+                               return ret;
                }
        }
 
-       return buffer_size - rest;
+       return result;
 }
 
 static int ocfs2_xattr_ibody_list(struct inode *inode,
@@ -2456,6 +2479,7 @@ out:
 struct ocfs2_xattr_tree_list {
        char *buffer;
        size_t buffer_size;
+       size_t result;
 };
 
 static int ocfs2_xattr_bucket_get_name_value(struct inode *inode,
@@ -2481,17 +2505,17 @@ static int ocfs2_list_xattr_bucket(struct inode *inode,
                                   struct ocfs2_xattr_bucket *bucket,
                                   void *para)
 {
-       int ret = 0;
+       int ret = 0, type;
        struct ocfs2_xattr_tree_list *xl = (struct ocfs2_xattr_tree_list *)para;
-       size_t size;
        int i, block_off, new_offset;
+       const char *prefix, *name;
 
        for (i = 0 ; i < le16_to_cpu(bucket->xh->xh_count); i++) {
                struct ocfs2_xattr_entry *entry = &bucket->xh->xh_entries[i];
-               struct xattr_handler *handler =
-                       ocfs2_xattr_handler(ocfs2_xattr_get_type(entry));
+               type = ocfs2_xattr_get_type(entry);
+               prefix = ocfs2_xattr_prefix(type);
 
-               if (handler) {
+               if (prefix) {
                        ret = ocfs2_xattr_bucket_get_name_value(inode,
                                                                bucket->xh,
                                                                i,
@@ -2499,16 +2523,16 @@ static int ocfs2_list_xattr_bucket(struct inode *inode,
                                                                &new_offset);
                        if (ret)
                                break;
-                       size = handler->list(inode, xl->buffer, xl->buffer_size,
-                                            bucket->bhs[block_off]->b_data +
-                                            new_offset,
-                                            entry->xe_name_len);
-                       if (xl->buffer) {
-                               if (size > xl->buffer_size)
-                                       return -ERANGE;
-                               xl->buffer += size;
-                       }
-                       xl->buffer_size -= size;
+
+                       name = (const char *)bucket->bhs[block_off]->b_data +
+                               new_offset;
+                       ret = ocfs2_xattr_list_entry(xl->buffer,
+                                                    xl->buffer_size,
+                                                    &xl->result,
+                                                    prefix, name,
+                                                    entry->xe_name_len);
+                       if (ret)
+                               break;
                }
        }
 
@@ -2527,6 +2551,7 @@ static int ocfs2_xattr_tree_list_index_block(struct inode *inode,
        struct ocfs2_xattr_tree_list xl = {
                .buffer = buffer,
                .buffer_size = buffer_size,
+               .result = 0,
        };
 
        if (le16_to_cpu(el->l_next_free_rec) == 0)
@@ -2554,7 +2579,7 @@ static int ocfs2_xattr_tree_list_index_block(struct inode *inode,
                name_hash = e_cpos - 1;
        }
 
-       ret = buffer_size - xl.buffer_size;
+       ret = xl.result;
 out:
        return ret;
 }