Changeset 47faec1 in mainline for uspace/lib/ext4/libext4_extent.c

Timestamp:

2012-03-26T09:42:16Z (12 years ago)

Author:

Frantisek Princ <frantisek.princ@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

fffb061

Parents:

9463b245

Message:

introduced binary search in extent index node

File:

• uspace/lib/ext4/libext4_extent.c (modified) (3 diffs)

uspace/lib/ext4/libext4_extent.c

@@ -149 +149 @@
 }
 
-//static void ext4_extent_binsearch_idx(ext4_extent_header_t *header,
-//      ext4_extent_index_t **index, uint32_t iblock)
-//{
-//      ext4_extent_index_t *r, *l, *m;
-//
-//      uint16_t entries_count = ext4_extent_header_get_entries_count(header);
-//      l = EXT4_EXTENT_FIRST_INDEX(header) + 1;
-//      r = l + entries_count - 1;
-//
-//      while (l <= r) {
-//              m = l + (r - l) / 2;
-//              uint32_t block = ext4_extent_index_get_first_block(m);
-//              if (iblock < block) {
-//                              r = m - 1;
-//              } else {
-//                              l = m + 1;
-//              }
-//      }
-//
-//      *index = l - 1;
-//}
-//
-static void ext4_extent_binsearch(ext4_extent_header_t *header,
-                ext4_extent_t **extent, uint32_t iblock)
-{
-        ext4_extent_t *r, *l, *m;
+static void ext4_extent_binsearch_idx(ext4_extent_header_t *header,
+        ext4_extent_index_t **index, uint32_t iblock)
+{
+        ext4_extent_index_t *r, *l, *m;
 
         uint16_t entries_count = ext4_extent_header_get_entries_count(header);
 
-        if (entries_count == 0) {
-                // this leaf is empty
+        if (entries_count == 1) {
+                *index = EXT4_EXTENT_FIRST_INDEX(header);
                 return;
         }
 
-        l = EXT4_EXTENT_FIRST(header) + 1;
+        l = EXT4_EXTENT_FIRST_INDEX(header) + 1;
         r = l + entries_count - 1;
 
         while (l <= r) {
                 m = l + (r - l) / 2;
-                uint32_t block = ext4_extent_get_first_block(m);
-                if (iblock < block) {
+                uint32_t first_block = ext4_extent_index_get_first_block(m);
+                if (iblock < first_block) {
                                 r = m - 1;
                 } else {
@@ -196 +174 @@
         }
 
+        *index = l - 1;
+}
+
+static void ext4_extent_binsearch(ext4_extent_header_t *header,
+                ext4_extent_t **extent, uint32_t iblock)
+{
+        ext4_extent_t *r, *l, *m;
+
+        uint16_t entries_count = ext4_extent_header_get_entries_count(header);
+
+        if (entries_count == 0) {
+                // this leaf is empty
+                EXT4FS_DBG("EMPTY LEAF");
+                *extent = NULL;
+                return;
+        }
+
+        if (entries_count == 1) {
+                *extent = EXT4_EXTENT_FIRST(header);
+                return;
+        }
+
+        l = EXT4_EXTENT_FIRST(header) + 1;
+        r = l + entries_count - 1;
+
+        while (l <= r) {
+                m = l + (r - l) / 2;
+                uint32_t first_block = ext4_extent_get_first_block(m);
+                if (iblock < first_block) {
+                                r = m - 1;
+                } else {
+                                l = m + 1;
+                }
+        }
+
         *extent = l - 1;
-
 }
 
@@ -210 +222 @@
         while (ext4_extent_header_get_depth(header) != 0) {
 
-//              ext4_extent_path_t path2;
-//              path2.header = header;
-//              path2.index = NULL;
-//              ext4_extent_binsearch_idx(header, &path2.index, iblock);
-//
-//              uint64_t child = ext4_extent_index_get_leaf(path2.index);
-//              if (block != NULL) {
-//                      block_put(block);
-//              }
-//
-//              rc = block_get(&block, fs->device, child, BLOCK_FLAGS_NONE);
-//              if (rc != EOK) {
-//                      return rc;
-//              }
-//
-//              header = block->data;
-//              break;
-
-
-                ext4_extent_index_t *extent_index = EXT4_EXTENT_FIRST_INDEX(header);
-
-                for (uint16_t i = 0; i < ext4_extent_header_get_entries_count(header); ++i, extent_index++) {
-                        if (iblock >= ext4_extent_index_get_first_block(extent_index)) {
-
-                                uint64_t child = ext4_extent_index_get_leaf(extent_index);
-
-                                if (block != NULL) {
-                                        block_put(block);
-                                }
-
-                                rc = block_get(&block, fs->device, child, BLOCK_FLAGS_NONE);
-                                if (rc != EOK) {
-                                        return rc;
-                                }
-
-                                header = (ext4_extent_header_t *)block->data;
-                                break;
-                        }
+                ext4_extent_index_t *index;
+                ext4_extent_binsearch_idx(header, &index, iblock);
+
+                uint64_t child = ext4_extent_index_get_leaf(index);
+
+                if (block != NULL) {
+                        block_put(block);
                 }
-        }
-
-
-        ext4_extent_path_t path;
-
-        path.header = header;
-        path.extent = NULL;
-
-        ext4_extent_binsearch(path.header, &path.extent, iblock);
-
-        *ret_extent = path.extent;
+
+                rc = block_get(&block, fs->device, child, BLOCK_FLAGS_NONE);
+                if (rc != EOK) {
+                        return rc;
+                }
+
+                header = (ext4_extent_header_t *)block->data;
+        }
+
+
+        ext4_extent_t *extent = NULL;
+        ext4_extent_binsearch(header, &extent, iblock);
+        *ret_extent = extent;
 
         return EOK;