Changeset b4b7187 in mainline

Timestamp:

2008-10-25T19:38:38Z (16 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

8b0bc1f

Parents:

6f2dfd1

Message:

Implementation of fat_fill_gap().

File:

• uspace/srv/fs/fat/fat_ops.c (modified) (6 diffs)

uspace/srv/fs/fat/fat_ops.c

@@ -850 +850 @@
 }
 
+/** Fill the gap between EOF and a new file position.
+ *
+ * @param nodep         FAT node with the gap.
+ * @param mcl           First cluster in an independent cluster chain that will
+ *                      be later appended to the end of the node's own cluster
+ *                      chain. If pos is still in the last allocated cluster,
+ *                      this argument is ignored.
+ * @param pos           Position in the last node block.
+ */
 static void
-fat_fill_gap(fat_node_t *nodep, fat_cluster_t mclst, off_t pos)
-{
-        /* TODO */
+fat_fill_gap(fat_node_t *nodep, fat_cluster_t mcl, off_t pos)
+{
+        uint16_t bps;
+        unsigned spc;
+        block_t *bb, *b;
+        off_t o, boundary;
+
+        bb = block_get(nodep->idx->dev_handle, BS_BLOCK, BS_SIZE);
+        bps = uint16_t_le2host(FAT_BS(bb)->bps);
+        spc = FAT_BS(bb)->spc;
+        block_put(bb);
+        
+        boundary = ROUND_UP(nodep->size, bps * spc);
+
+        /* zero out already allocated space */
+        for (o = nodep->size - 1; o < pos && o < boundary;
+            o = ALIGN_DOWN(o + bps, bps)) {
+                b = fat_block_get(nodep, o / bps);
+                memset(b->data + o % bps, 0, bps - o % bps);
+                b->dirty = true;                /* need to sync node */
+                block_put(b);
+        }
+        
+        if (o >= pos)
+                return;
+        
+        /* zero out the initial part of the new cluster chain */
+        for (o = boundary; o < pos; o += bps) {
+                b = _fat_block_get(nodep->idx->dev_handle, mcl,
+                    (o - boundary) / bps);
+                memset(b->data, 0, min(bps, pos - o));
+                b->dirty = true;
+                block_put(b);
+        }
 }
 
@@ -877 +917 @@
         uint16_t bps;
         unsigned spc;
-        off_t clst_boundary;
+        off_t boundary;
         
         if (!nodep) {
@@ -914 +954 @@
         block_put(bb);
         
-        clst_boundary = ROUND_UP(nodep->size, bps * spc);
-        if (pos < clst_boundary) {
+        boundary = ROUND_UP(nodep->size, bps * spc);
+        if (pos < boundary) {
                 /*
                  * This is the easier case - we are either overwriting already
@@ -944 +984 @@
                 fat_cluster_t mcl, lcl;
         
-                nclsts = (ROUND_UP(pos + bytes, bps * spc) - clst_boundary) /
+                nclsts = (ROUND_UP(pos + bytes, bps * spc) - boundary) /
                     bps * spc;
                 /* create an independent chain of nclsts clusters in all FATs */
@@ -960 +1000 @@
                 (void) ipc_data_write_finalize(callid, b->data + pos % bps,
                     bytes);
-                b->dirty = true;
+                b->dirty = true;                /* need to sync block */
                 block_put(b);
                 /*
@@ -968 +1008 @@
                 fat_append_clusters(nodep, mcl);
                 nodep->size = pos + bytes;
-                nodep->dirty = true;
+                nodep->dirty = true;            /* need to sync node */
                 fat_node_put(nodep);
                 ipc_answer_1(rid, EOK, bytes);