Changeset 8d1aab7 in mainline for uspace/srv/fs/pipefs/pipefs_ops.c

Timestamp:

2010-11-24T18:59:47Z (13 years ago)

Author:

Martin Sucha <sucha14@…>

Branches:

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

Children:

f5648d8

Parents:

5bd4f2c

Message:

Changes for simple pipefs behaviour. Currently it does not support waiting for data.

File:

• uspace/srv/fs/pipefs/pipefs_ops.c (modified) (6 diffs)

uspace/srv/fs/pipefs/pipefs_ops.c

@@ -190 +190 @@
         }
 
-        if (nodep->data) {
+        while (!list_empty(&nodep->data_head)) {
                 assert(nodep->type == PIPEFS_FILE);
-                free(nodep->data);
+                
+                pipefs_data_block_t *data_block = list_get_instance(nodep->data_head.next,
+                    pipefs_data_block_t, link);
+                
+                list_remove(&data_block->link);
+                free(data_block->data);
+                free(data_block);
         }
         free(nodep->bp);
@@ -212 +218 @@
         nodep->type = PIPEFS_NONE;
         nodep->lnkcnt = 0;
+        nodep->start = 0;
         nodep->size = 0;
-        nodep->data = NULL;
+        list_initialize(&nodep->data_head);
         link_initialize(&nodep->nh_link);
         list_initialize(&nodep->cs_head);
@@ -536 +543 @@
         size_t bytes;
         if (nodep->type == PIPEFS_FILE) {
-                bytes = min(nodep->size - pos, size);
-                (void) async_data_read_finalize(callid, nodep->data + pos,
-                    bytes);
+                /*
+                 * Check if we still have the requested data.
+                 * This may happen if the client seeked backwards
+                 */
+                if (pos < nodep->start) {
+                        ipc_answer_0(callid, ENOTSUP);
+                        ipc_answer_0(rid, ENOTSUP);
+                        return;
+                }
+                
+                /*
+                 * Free all data blocks that end before pos.
+                 * This is in case the client seeked forward 
+                 */
+                while (!list_empty(&nodep->data_head)) {
+                        pipefs_data_block_t *data_block =
+                            list_get_instance(nodep->data_head.next,
+                                pipefs_data_block_t, link);
+                
+                        aoff64_t block_end = nodep->start + data_block->size;
+                        
+                        if (block_end > pos) {
+                                break;
+                        }
+                        
+                        list_remove(&data_block->link);
+                        free(data_block->data);
+                        free(data_block);
+                        nodep->start = block_end;
+                }
+                
+                if (!list_empty(&nodep->data_head)) {
+                        /* We have data block, so let's return its portion after pos */
+                        pipefs_data_block_t *data_block =
+                            list_get_instance(nodep->data_head.next,
+                                pipefs_data_block_t, link);
+                        
+                        assert(nodep->start <= pos);
+                        
+                        aoff64_t block_end = nodep->start + data_block->size;
+                        size_t block_offset = pos - nodep->start;
+                        
+                        assert(block_end > pos);
+                        
+                        bytes = min(block_end - pos, size);
+                        (void) async_data_read_finalize(callid,
+                            data_block->data + block_offset,
+                            bytes);
+                        
+                        if (nodep->start + block_offset + bytes == block_end) {
+                                /* Free the data block - it was fully read */
+                                list_remove(&data_block->link);
+                                free(data_block->data);
+                                free(data_block);
+                                nodep->start = block_end;
+                        }
+                }
+                else {
+                        /*
+                         * there is no data
+                         * TODO implement waiting for the data
+                         * and remove this else clause
+                         */
+                        ipc_answer_0(callid, ENOTSUP);
+                        ipc_answer_1(rid, ENOTSUP, 0);
+                        return;
+                }
         } else {
                 pipefs_dentry_t *dentryp;
@@ -610 +681 @@
 
         /*
-         * Check whether the file needs to grow.
-         */
-        if (pos + size <= nodep->size) {
-                /* The file size is not changing. */
-                (void) async_data_write_finalize(callid, nodep->data + pos, size);
-                ipc_answer_2(rid, EOK, size, nodep->size);
-                return;
-        }
-        size_t delta = (pos + size) - nodep->size;
-        /*
-         * At this point, we are deliberately extremely straightforward and
-         * simply realloc the contents of the file on every write that grows the
-         * file. In the end, the situation might not be as bad as it may look:
-         * our heap allocator can save us and just grow the block whenever
-         * possible.
-         */
-        void *newdata = realloc(nodep->data, nodep->size + delta);
+         * Check whether we are writing to the end
+         */
+        if (pos != nodep->size) {
+                ipc_answer_0(callid, ENOTSUP);
+                ipc_answer_2(rid, EOK, 0, nodep->size);
+                return;
+        }
+        
+        /*
+         * Allocate a buffer for the new data.
+         * Currently we accept any size, create a data block from this
+         * and append it to the end of a file
+         */
+        void *newdata = malloc(size);
         if (!newdata) {
                 ipc_answer_0(callid, ENOMEM);
@@ -632 +700 @@
                 return;
         }
-        /* Clear any newly allocated memory in order to emulate gaps. */
-        memset(newdata + nodep->size, 0, delta);
-        nodep->size += delta;
-        nodep->data = newdata;
-        (void) async_data_write_finalize(callid, nodep->data + pos, size);
+        
+        pipefs_data_block_t *newblock = malloc(sizeof(pipefs_data_block_t));
+        
+        if (!newblock) {
+                free(newdata);
+                ipc_answer_0(callid, ENOMEM);
+                ipc_answer_2(rid, EOK, 0, nodep->size);
+                return;
+        }
+        
+        int rc = async_data_write_finalize(callid, newdata, size);
+        
+        if (rc != EOK) {
+                free(newblock);
+                free(newdata);
+                ipc_answer_0(callid, rc);
+                ipc_answer_2(rid, EOK, 0, nodep->size);
+                return;
+        }
+        
+        link_initialize(&newblock->link);
+        newblock->size = size;
+        newblock->data = newdata;
+        list_append(&newblock->link, &nodep->data_head);
+        
+        nodep->size += size;
+        
         ipc_answer_2(rid, EOK, size, nodep->size);
 }
@@ -642 +732 @@
 void pipefs_truncate(ipc_callid_t rid, ipc_call_t *request)
 {
-        devmap_handle_t devmap_handle = (devmap_handle_t) IPC_GET_ARG1(*request);
-        fs_index_t index = (fs_index_t) IPC_GET_ARG2(*request);
-        aoff64_t size =
-            (aoff64_t) MERGE_LOUP32(IPC_GET_ARG3(*request), IPC_GET_ARG4(*request));
-        
-        /*
-         * Lookup the respective PIPEFS node.
-         */
-        unsigned long key[] = {
-                [NODES_KEY_DEV] = devmap_handle,
-                [NODES_KEY_INDEX] = index
-        };
-        link_t *hlp = hash_table_find(&nodes, key);
-        if (!hlp) {
-                ipc_answer_0(rid, ENOENT);
-                return;
-        }
-        pipefs_node_t *nodep = hash_table_get_instance(hlp, pipefs_node_t,
-            nh_link);
-        
-        if (size == nodep->size) {
-                ipc_answer_0(rid, EOK);
-                return;
-        }
-        
-        if (size > SIZE_MAX) {
-                ipc_answer_0(rid, ENOMEM);
-                return;
-        }
-        
-        void *newdata = realloc(nodep->data, size);
-        if (!newdata) {
-                ipc_answer_0(rid, ENOMEM);
-                return;
-        }
-        
-        if (size > nodep->size) {
-                size_t delta = size - nodep->size;
-                memset(newdata + nodep->size, 0, delta);
-        }
-        
-        nodep->size = size;
-        nodep->data = newdata;
-        ipc_answer_0(rid, EOK);
+        /*
+         * PIPEFS does not support resizing of files
+         */
+        ipc_answer_0(rid, ENOTSUP);
 }