Changeset e2115311 in mainline

Timestamp:

2008-08-15T20:02:36Z (16 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

8af22d6

Parents:

7c1d121

Message:

Determine the size of a directory node by walking the FAT and counting clusters.
This eliminates the hardcoded limit on the number of directory entries.

File:

• uspace/srv/fs/fat/fat_ops.c (modified) (2 diffs)

uspace/srv/fs/fat/fat_ops.c

@@ -224 +224 @@
 }
 
+/** Return number of blocks allocated to a file.
+ *
+ * @param dev_handle    Device handle of the device with the file.
+ * @param firstc        First cluster of the file.
+ *
+ * @return              Number of blocks allocated to the file.
+ */
+static uint16_t 
+_fat_blcks_get(dev_handle_t dev_handle, fat_cluster_t firstc)
+{
+        block_t *bb;
+        block_t *b;
+        unsigned bps;
+        unsigned spc;
+        unsigned rscnt;         /* block address of the first FAT */
+        unsigned clusters = 0;
+        fat_cluster_t clst = firstc;
+
+        bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
+        bps = uint16_t_le2host(FAT_BS(bb)->bps);
+        spc = FAT_BS(bb)->spc;
+        rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
+        block_put(bb);
+
+        if (firstc == FAT_CLST_RES0) {
+                /* No space allocated to the file. */
+                return 0;
+        }
+
+        while (clst < FAT_CLST_LAST1) {
+                unsigned fsec;  /* sector offset relative to FAT1 */
+                unsigned fidx;  /* FAT1 entry index */
+
+                assert(clst >= FAT_CLST_FIRST);
+                fsec = (clst * sizeof(fat_cluster_t)) / bps;
+                fidx = clst % (bps / sizeof(fat_cluster_t));
+                /* read FAT1 */
+                b = block_get(dev_handle, rscnt + fsec, bps);
+                clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
+                assert(clst != FAT_CLST_BAD);
+                block_put(b);
+                clusters++;
+        }
+
+        return clusters * spc;
+}
+
 static void fat_node_initialize(fat_node_t *node)
 {
@@ -360 +407 @@
                 nodep->type = FAT_DIRECTORY;
                 /*
-                 * TODO: determine the size by walking FAT. Surprisingly, the
-                 * 'size' filed of the FAT dentry is not defined for the
-                 * directory entry type.
+                 * Unfortunately, the 'size' field of the FAT dentry is not
+                 * defined for the directory entry type. We must determine the
+                 * size of the directory by walking the FAT.
                  */
-                nodep->size = 64 * sizeof(fat_dentry_t);
+                nodep->size = bps * _fat_blcks_get(idxp->dev_handle,
+                    uint16_t_le2host(d->firstc));
         } else {
                 nodep->type = FAT_FILE;