Changeset 11882

Timestamp:

03/17/05 15:25:07 (4 years ago)

Author:

bonefish

Message:

We were handling closing of file descriptors incorrectly. The close_*()
and free_*_cookie() hooks of the underlying FS were always called
together when the reference count of the FD dropped to zero. When
blocking operations (reading/writing) on the FD were still in progress
this would never happen, though. Now we additionally maintain an open
count and call the close_*() hook when it drops to zero.

Location:

haiku/trunk

Files:

• headers/private/kernel/fd.h (modified) (1 diff)
• src/kernel/core/fs/fd.c (modified) (8 diffs)

haiku/trunk/headers/private/kernel/fd.h

@@ -37 +37 @@
         int32   type;               /* descriptor type */
         int32   ref_count;
+        int32   open_count;
         struct fd_ops *ops;
         union {

haiku/trunk/src/kernel/core/fs/fd.c

@@ -55 +55 @@
         descriptor->cookie = NULL;
         descriptor->ref_count = 1;
+        descriptor->open_count = 1;
         descriptor->open_mode = 0;
         descriptor->pos = 0;
@@ -109 +110 @@
         // free the descriptor if we don't need it anymore
         if (atomic_add(&descriptor->ref_count, -1) == 1) {
-                // close the underlying object (and free any resources allocated there)
-                if (descriptor->ops->fd_close)
-                        descriptor->ops->fd_close(descriptor);
+                // free the underlying object
                 if (descriptor->ops->fd_free)
                         descriptor->ops->fd_free(descriptor);
@@ -142 +141 @@
 
 
-/**     Removes the file descriptor in the specified slot, and
- *      reduces its reference counter.
+/**     Removes the file descriptor in the specified slot.
  */
 
-static void
+static struct file_descriptor *
 remove_fd(struct io_context *context, int fd)
 {
@@ -152 +150 @@
 
         if (fd < 0)
-                return;
+                return NULL;
 
         mutex_lock(&context->io_mutex);
@@ -166 +164 @@
         mutex_unlock(&context->io_mutex);
 
-        if (descriptor)
-                put_fd(descriptor);
+        return descriptor;
 }
 
@@ -303 +300 @@
 
 
+static status_t
+common_close(int fd, bool kernel)
+{
+        struct io_context *io = get_current_io_context(kernel);
+        struct file_descriptor *descriptor = remove_fd(io, fd);
+
+        if (descriptor == NULL)
+                return B_FILE_ERROR;
+
+        #ifdef TRACE_FD
+                if (!kernel)
+                        TRACE(("_user_close(descriptor = %p)\n", descriptor));
+        #endif
+
+        if (atomic_add(&descriptor->open_count, -1) == 1) {
+                if (descriptor->ops->fd_close)
+                        descriptor->ops->fd_close(descriptor);
+        }
+
+        put_fd(descriptor);
+                // the reference associated with the slot
+
+        return B_OK;
+}
+
+
 //      #pragma mark -
 /*** USER routines ***/ 
@@ -593 +616 @@
 _user_close(int fd)
 {
-        struct io_context *io = get_current_io_context(false);
-        struct file_descriptor *descriptor = get_fd(io, fd);
-
-        if (descriptor == NULL)
-                return B_FILE_ERROR;
-
-        TRACE(("user_close(descriptor = %p)\n", descriptor));
-
-        remove_fd(io, fd);
-
-        put_fd(descriptor);
-        return B_OK;
+        return common_close(fd, true);
 }
 
@@ -857 +869 @@
 _kern_close(int fd)
 {
-        struct io_context *io = get_current_io_context(true);
-        struct file_descriptor *descriptor = get_fd(io, fd);
-
-        if (descriptor == NULL)
-                return B_FILE_ERROR;
-
-        remove_fd(io, fd);
-
-        put_fd(descriptor);
-        return B_OK;
+        return common_close(fd, true);
 }