Changeset 913a821c in mainline for uspace/srv/fs/fat/fat_ops.c

Timestamp:

2008-11-09T17:23:53Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

ac49f5d1

Parents:

6c8d267

Message:

Finish implementation of fat_truncate() and fix several warnings.

File:

• uspace/srv/fs/fat/fat_ops.c (modified) (7 diffs)

uspace/srv/fs/fat/fat_ops.c

@@ -635 +635 @@
         uint16_t bps;
         unsigned spc;
+        unsigned bpc;           /* bytes per cluster */
         off_t boundary;
         
@@ -650 +651 @@
                 return;
         }
+
+        bs = block_bb_get(dev_handle);
+        bps = uint16_t_le2host(bs->bps);
+        spc = bs->spc;
+        bpc = bps * spc;
 
         /*
@@ -659 +665 @@
          */ 
         bytes = min(len, bps - pos % bps);
-
-        bs = block_bb_get(dev_handle);
-        bps = uint16_t_le2host(bs->bps);
-        spc = bs->spc;
-        
-        boundary = ROUND_UP(nodep->size, bps * spc);
+        
+        boundary = ROUND_UP(nodep->size, bpc);
         if (pos < boundary) {
                 /*
@@ -694 +696 @@
                 fat_cluster_t mcl, lcl; 
  
-                nclsts = (ROUND_UP(pos + bytes, bps * spc) - boundary) /
-                    bps * spc;
+                nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
                 /* create an independent chain of nclsts clusters in all FATs */
-                status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl,
-                    &lcl);
+                status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
                 if (status != EOK) {
                         /* could not allocate a chain of nclsts clusters */
@@ -732 +732 @@
         size_t size = (off_t)IPC_GET_ARG3(*request);
         fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
+        fat_bs_t *bs;
+        uint16_t bps;
+        uint8_t spc;
+        unsigned bpc;   /* bytes per cluster */
         int rc;
 
@@ -738 +742 @@
                 return;
         }
+
+        bs = block_bb_get(dev_handle);
+        bps = uint16_t_le2host(bs->bps);
+        spc = bs->spc;
+        bpc = bps * spc;
 
         if (nodep->size == size) {
@@ -743 +752 @@
         } else if (nodep->size < size) {
                 /*
-                 * TODO: the standard says we have the freedom to grow the file.
+                 * The standard says we have the freedom to grow the node.
                  * For now, we simply return an error.
                  */
                 rc = EINVAL;
+        } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
+                /*
+                 * The node will be shrunk, but no clusters will be deallocated.
+                 */
+                nodep->size = size;
+                nodep->dirty = true;            /* need to sync node */
+                rc = EOK;       
         } else {
                 /*
-                 * The file is to be shrunk.
-                 */
-                rc = ENOTSUP;   /* XXX */
+                 * The node will be shrunk, clusters will be deallocated.
+                 */
+                if (size == 0) {
+                        fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
+                } else {
+                        fat_cluster_t lastc;
+                        (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
+                            &lastc, (size - 1) / bpc);
+                        fat_chop_clusters(bs, nodep, lastc);
+                }
+                nodep->size = size;
+                nodep->dirty = true;            /* need to sync node */
+                rc = EOK;       
         }
         fat_node_put(nodep);
         ipc_answer_0(rid, rc);
         return;
-
 }