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>

1 files changed, 60 insertions, 35 deletions

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 092a1231898..8f522f2f84a 100644
--- 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;
 }