Changeset 4b995b92 in mainline

Timestamp:

2010-01-24T13:02:17Z (14 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

203a090

Parents:

c1a8e5e6

Message:

Introduce the L_NOCROSS_LAST_MP lookup flag and treat the last mount point node
according to it in libfs_lookup().

Location:

uspace

Files:

• lib/libc/include/ipc/vfs.h (modified) (1 diff)
• lib/libfs/libfs.c (modified) (1 diff)
• srv/vfs/vfs_ops.c (modified) (1 diff)

uspace/lib/libc/include/ipc/vfs.h

@@ -148 +148 @@
 #define L_OPEN  64
 
+/**
+ * L_NOCROSS_LAST_MP is used exclusively during the VFS_IN_UNMOUNT operation. It
+ * tells the lookup routine not to cross the last mount point in the lookup
+ * path.
+ */
+#define L_NOCROSS_LAST_MP       128
+
 #endif
 

uspace/lib/libfs/libfs.c

@@ -304 +304 @@
                 on_error(rc, goto out_with_answer);
                 
-                if ((tmp) && (tmp->mp_data.mp_active)) {
+                /*
+                 * If the matching component is a mount point, there are two
+                 * legitimate semantics of the lookup operation. The first is
+                 * the commonly used one in which the lookup crosses each mount
+                 * point into the mounted file system. The second semantics is
+                 * used mostly during unmount() and differs from the first one
+                 * only in that the last mount point in the looked up path,
+                 * which is also its last component, is not crossed.
+                 */
+
+                if ((tmp) && (tmp->mp_data.mp_active) &&
+                    (!(lflag & L_NOCROSS_LAST_MP) || (next <= last))) {
                         if (next > last)
                                 next = last = first;

uspace/srv/vfs/vfs_ops.c

@@ -459 +459 @@
         /*
          * Make sure that we are called with exactly one of L_FILE and
-         * L_DIRECTORY. Make sure that the user does not pass L_OPEN.
+         * L_DIRECTORY. Make sure that the user does not pass L_OPEN or
+         * L_NOCROSS_LAST_MP.
          */
         if (((lflag & (L_FILE | L_DIRECTORY)) == 0) ||
             ((lflag & (L_FILE | L_DIRECTORY)) == (L_FILE | L_DIRECTORY)) ||
-            ((lflag & L_OPEN) != 0)) {
+            (lflag & L_OPEN) || (lflag & L_NOCROSS_LAST_MP)) {
                 ipc_answer_0(rid, EINVAL);
                 return;