Do not pad the final block of a file with zeroes.

[bluesky.git] / bluesky / file.c

diff --git a/bluesky/file.c b/bluesky/file.c
index 607d611..75768d1 100644 (file)
--- a/bluesky/file.c
+++ b/bluesky/file.c
@@ -21,10 +21,17 @@ void bluesky_block_touch(BlueSkyInode *inode, uint64_t i)
     g_return_if_fail(i < inode->blocks->len);
     BlueSkyBlock *block = &g_array_index(inode->blocks, BlueSkyBlock, i);
 
+    gsize block_len;
+    if (i < inode->blocks->len - 1) {
+        block_len = BLUESKY_BLOCK_SIZE;
+    } else {
+        block_len = inode->size - i * BLUESKY_BLOCK_SIZE;
+    }
+
     switch (block->type) {
     case BLUESKY_BLOCK_ZERO:
-        block->data = bluesky_string_new(g_malloc0(BLUESKY_BLOCK_SIZE),
-                                         BLUESKY_BLOCK_SIZE);
+        g_print("Allocating zero block of size %zd\n", block_len);
+        block->data = bluesky_string_new(g_malloc0(block_len), block_len);
         break;
     case BLUESKY_BLOCK_REF:
         bluesky_block_fetch(inode->fs, block);
@@ -65,17 +72,21 @@ void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size)
         g_array_set_size(inode->blocks, blocks);
     }
 
-    /* If the file size is being decreased, ensure that any trailing data in
-     * the last block is zeroed. */
-    if (size < inode->size) {
+    /* Ensure the last block of the file is properly sized.  If the block is
+     * extended, newly-added bytes must be zeroed. */
+    if (blocks > 0) {
         BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock,
                                          blocks - 1);
+
         if (b->type != BLUESKY_BLOCK_ZERO) {
             bluesky_block_touch(inode, blocks - 1);
-            int end_offset = size % BLUESKY_BLOCK_SIZE;
-            if (end_offset > 0) {
-                memset(&b->data->data[end_offset], 0,
-                       BLUESKY_BLOCK_SIZE - end_offset);
+            gsize old_size = b->data->len;
+            gsize new_size = size - (blocks - 1) * BLUESKY_BLOCK_SIZE;
+
+            bluesky_string_resize(b->data, new_size);
+
+            if (new_size > old_size) {
+                memset(&b->data->data[old_size], 0, new_size - old_size);
             }
         }
     }