Changeset 6c117bb in mainline

Timestamp:

2007-09-27T18:14:02Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

566d798d

Parents:

37e7dc54

Message:

VFS work.
Proto implementation of VFS-side vfs_lookup_internal().

Location:

uspace/srv/vfs

Files:

• vfs.h (modified) (1 diff)
• vfs_lookup.c (modified) (1 diff)

uspace/srv/vfs/vfs.h

@@ -143 +143 @@
 extern link_t plb_head;         /**< List of active PLB entries. */
 
+extern int vfs_lookup_internal(char *path, size_t len, vfs_node_t *result);
+
 extern void vfs_register(ipc_callid_t, ipc_call_t *);
-extern void vfs_lookup(ipc_callid_t, ipc_call_t *);
+extern void vfs_mount(ipc_callid_t, ipc_call_t *);
 
 #endif

uspace/srv/vfs/vfs_lookup.c

@@ -46 +46 @@
 #include "vfs.h"
 
+#define min(a, b)       ((a) < (b) ? (a) : (b))
+
 atomic_t plb_futex = FUTEX_INITIALIZER;
-link_t plb_head;
+link_t plb_head;        /**< PLB entry ring buffer. */
 uint8_t *plb = NULL;
 
-void vfs_lookup(ipc_callid_t rid, ipc_call_t *request)
+int vfs_lookup_internal(char *path, size_t len, vfs_node_t *result)
 {
+        if (!len)
+                return EINVAL;
+
         if (!rootfs)
-                ipc_answer_fast(rid, ENOENT, 0, 0);
+                return ENOENT;
+        
+        futex_down(&plb_futex);
+
+        plb_entry_t entry;
+        link_initialize(&entry.plb_link);
+        entry.len = len;
+
+        off_t first;    /* the first free index */
+        off_t last;     /* the last free index */
+
+        if (list_empty(&plb_head)) {
+                first = 0;
+                last = PLB_SIZE - 1;
+        } else {
+                plb_entry_t *oldest = list_get_instance(plb_head.next,
+                    plb_entry_t, plb_link);
+                plb_entry_t *newest = list_get_instance(plb_head.prev,
+                    plb_entry_t, plb_link);
+
+                first = (newest->index + newest->len) % PLB_SIZE;
+                last = (oldest->index - 1) % PLB_SIZE;
+        }
+
+        if (first <= last) {
+                if ((last - first) + 1 < len) {
+                        /*
+                         * The buffer cannot absorb the path.
+                         */
+                        futex_up(&plb_futex);
+                        return ELIMIT;
+                }
+        } else {
+                if (PLB_SIZE - ((first - last) + 1) < len) {
+                        /*
+                         * The buffer cannot absorb the path.
+                         */
+                        futex_up(&plb_futex);
+                        return ELIMIT;
+                }
+        }
+
+        /*
+         * We know the first free index in PLB and we also know that there is
+         * enough space in the buffer to hold our path.
+         */
+
+        entry.index = first;
+        entry.len = len;
+
+        /*
+         * Claim PLB space by inserting the entry into the PLB entry ring
+         * buffer.
+         */
+        list_append(&entry.plb_link, &plb_head);
+        
+        futex_up(&plb_futex);
+
+        /*
+         * Copy the path into PLB.
+         */
+        size_t cnt1 = min(len, (PLB_SIZE - first) + 1);
+        size_t cnt2 = len - cnt1;
+        
+        memcpy(&plb[first], path, cnt1);
+        memcpy(plb, &path[cnt1], cnt2);
+
+        ipc_call_t answer;
+        int phone = 0;          /* TODO */
+        aid_t req = async_send_2(phone, VFS_LOOKUP, (ipcarg_t) first,
+            (ipcarg_t) last, &answer);
+
+        ipcarg_t rc;
+        async_wait_for(req, &rc);
+
+        futex_down(&plb_futex);
+        list_remove(&entry.plb_link);
+        futex_up(&plb_futex);
+
+        if (rc == EOK) {
+                result->fs_handle = (int) IPC_GET_ARG1(answer);
+                result->dev_handle = (int) IPC_GET_ARG2(answer);
+                result->index = (int) IPC_GET_ARG3(answer);
+        }
+
+        return rc;
 }