WebSVN – HelenOS – Diff – /branches/dynload/uspace/srv/fs/fat/fat_ops.c

     b->dirty = true;        /* need to sync block */
     block_put(b);
+}
+static fat_node_t *fat_node_get_new(void)
+{
+    fat_node_t *nodep;
+    futex_down(&ffn_futex);
+    if (!list_empty(&ffn_head)) {
+        /* Try to use a cached free node structure. */
+        fat_idx_t *idxp_tmp;
+        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
+        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
+            goto skip_cache;
+        idxp_tmp = nodep->idx;
+        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
+            futex_up(&nodep->lock);
+            goto skip_cache;
+        }
+        list_remove(&nodep->ffn_link);
+        futex_up(&ffn_futex);
+        if (nodep->dirty)
+            fat_node_sync(nodep);
+        idxp_tmp->nodep = NULL;
+        futex_up(&nodep->lock);
+        futex_up(&idxp_tmp->lock);
+    } else {
+skip_cache:
+        /* Try to allocate a new node structure. */
+        futex_up(&ffn_futex);
+        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
+        if (!nodep)
+            return NULL;
+    }
+    fat_node_initialize(nodep);
+    return nodep;
+}
 /** Internal version of fat_node_get().
+ *
  * @param idxp      Locked index structure.
  */
 static void *fat_node_get_core(fat_idx_t *idxp)
      * We must instantiate the node from the file system.
      */
     assert(idxp->pfc);
-    futex_down(&ffn_futex);
-    if (!list_empty(&ffn_head)) {
-        /* Try to use a cached free node structure. */
-        fat_idx_t *idxp_tmp;
-        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
-        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
-            goto skip_cache;
-        idxp_tmp = nodep->idx;
-        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
-            futex_up(&nodep->lock);
-            goto skip_cache;
-        }
-        list_remove(&nodep->ffn_link);
-        futex_up(&ffn_futex);
-        if (nodep->dirty)
-            fat_node_sync(nodep);
+    nodep = fat_node_get_new();
-        idxp_tmp->nodep = NULL;
-        futex_up(&nodep->lock);
-        futex_up(&idxp_tmp->lock);
-    } else {
-skip_cache:
-        /* Try to allocate a new node structure. */
-        futex_up(&ffn_futex);
-        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
-        if (!nodep)
+    if (!nodep)
-            return NULL;
+        return NULL;
-    }
-    fat_node_initialize(nodep);
     bs = block_bb_get(idxp->dev_handle);
     bps = uint16_t_le2host(bs->bps);
     spc = bs->spc;
     dps = bps / sizeof(fat_dentry_t);
         futex_up(&ffn_futex);
+    }
     futex_up(&nodep->lock);
+}
-static void *fat_create(int flags)
+static void *fat_create(dev_handle_t dev_handle, int flags)
+{
     return NULL;    /* not supported at the moment */
+}
 static int fat_destroy(void *node)
     fat_bs_t *bs;
     size_t bytes;
     block_t *b;
     uint16_t bps;
     unsigned spc;
+    unsigned bpc;       /* bytes per cluster */
     off_t boundary;
     if (!nodep) {
         ipc_answer_0(rid, ENOENT);
         return;
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
+    bs = block_bb_get(dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    spc = bs->spc;
+    bpc = bps * spc;
     /*
      * In all scenarios, we will attempt to write out only one block worth
      * of data at maximum. There might be some more efficient approaches,
      * but this one greatly simplifies fat_write(). Note that we can afford
      * to do this because the client must be ready to handle the return
      * value signalizing a smaller number of bytes written.
      */
     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) {
         /*
          * This is the easier case - we are either overwriting already
          * existing contents or writing behind the EOF, but still within
          * the limits of the last cluster. The node size may grow to the
         block_put(b);
         if (pos + bytes > nodep->size) {
             nodep->size = pos + bytes;
             nodep->dirty = true;    /* need to sync node */
+        }
+        ipc_answer_2(rid, EOK, bytes, nodep->size);
         fat_node_put(nodep);
-        ipc_answer_1(rid, EOK, bytes);
         return;
     } else {
         /*
          * This is the more difficult case. We must allocate new
          * clusters for the node and zero them out.
          */
         int status;
         unsigned nclsts;
         fat_cluster_t mcl, lcl;
-        nclsts = (ROUND_UP(pos + bytes, bps * spc) - boundary) /
+        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
-            bps * spc;
         /* create an independent chain of nclsts clusters in all FATs */
-        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl,
+        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
-            &lcl);
         if (status != EOK) {
             /* could not allocate a chain of nclsts clusters */
             fat_node_put(nodep);
             ipc_answer_0(callid, status);
             ipc_answer_0(rid, status);
          * node's cluster chain.
          */
         fat_append_clusters(bs, nodep, mcl);
         nodep->size = pos + bytes;
         nodep->dirty = true;        /* need to sync node */
+        ipc_answer_2(rid, EOK, bytes, nodep->size);
         fat_node_put(nodep);
-        ipc_answer_1(rid, EOK, bytes);
         return;
+    }
+}
 void fat_truncate(ipc_callid_t rid, ipc_call_t *request)
+{
     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
     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;
     if (!nodep) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
+    bs = block_bb_get(dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    spc = bs->spc;
+    bpc = bps * spc;
     if (nodep->size == size) {
         rc = EOK;
     } 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.
+         * 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 = ENOTSUP;   /* XXX */
+        rc = EOK;
+    }
     fat_node_put(nodep);
     ipc_answer_0(rid, rc);
     return;
+}
 /**
  * @}
  */

Subversion Repositories HelenOS

(root)/branches/dynload/uspace/srv/fs/fat/fat_ops.c – Rev 3561 → 3588