[PATCH] Make most file operations structs in fs/ const

[linux.git] / fs / fuse / dev.c

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 4526da8907c6d384fefee03b18bd6894558bf459..23d1f52eb1b8de693f86c96a8eccc2bb5909d750 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -66,6 +66,12 @@ static void restore_sigs(sigset_t *oldset)
        sigprocmask(SIG_SETMASK, oldset, NULL);
 }
 
        sigprocmask(SIG_SETMASK, oldset, NULL);
 }
 

+/*
+ * Reset request, so that it can be reused
+ *
+ * The caller must be _very_ careful to make sure, that it is holding
+ * the only reference to req
+ */

 void fuse_reset_request(struct fuse_req *req)
 {
        int preallocated = req->preallocated;
 void fuse_reset_request(struct fuse_req *req)
 {
        int preallocated = req->preallocated;


@@ -120,9 +126,9 @@ struct fuse_req *fuse_get_request(struct fuse_conn *fc)
        return do_get_request(fc);
 }
 
        return do_get_request(fc);
 }
 

+/* Must be called with fuse_lock held */

 static void fuse_putback_request(struct fuse_conn *fc, struct fuse_req *req)
 {
 static void fuse_putback_request(struct fuse_conn *fc, struct fuse_req *req)
 {

-       spin_lock(&fuse_lock);

        if (req->preallocated) {
                atomic_dec(&fc->num_waiting);
                list_add(&req->list, &fc->unused_list);
        if (req->preallocated) {
                atomic_dec(&fc->num_waiting);
                list_add(&req->list, &fc->unused_list);


@@ -134,10 +140,18 @@ static void fuse_putback_request(struct fuse_conn *fc, struct fuse_req *req)
                fc->outstanding_debt--;
        else
                up(&fc->outstanding_sem);
                fc->outstanding_debt--;
        else
                up(&fc->outstanding_sem);

-       spin_unlock(&fuse_lock);

 }
 
 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 }
 
 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)

+{
+       if (atomic_dec_and_test(&req->count)) {
+               spin_lock(&fuse_lock);
+               fuse_putback_request(fc, req);
+               spin_unlock(&fuse_lock);
+       }
+}
+
+static void fuse_put_request_locked(struct fuse_conn *fc, struct fuse_req *req)

 {
        if (atomic_dec_and_test(&req->count))
                fuse_putback_request(fc, req);
 {
        if (atomic_dec_and_test(&req->count))
                fuse_putback_request(fc, req);


@@ -163,26 +177,36 @@ void fuse_release_background(struct fuse_req *req)
  * still waiting), the 'end' callback is called if given, else the
  * reference to the request is released
  *
  * still waiting), the 'end' callback is called if given, else the
  * reference to the request is released
  *

+ * Releasing extra reference for foreground requests must be done
+ * within the same locked region as setting state to finished.  This
+ * is because fuse_reset_request() may be called after request is
+ * finished and it must be the sole possessor.  If request is
+ * interrupted and put in the background, it will return with an error
+ * and hence never be reset and reused.
+ *

  * Called with fuse_lock, unlocks it
  */
 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 {
  * Called with fuse_lock, unlocks it
  */
 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 {

-       void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
-       req->end = NULL;

        list_del(&req->list);
        req->state = FUSE_REQ_FINISHED;
        list_del(&req->list);
        req->state = FUSE_REQ_FINISHED;

-       spin_unlock(&fuse_lock);
-       if (req->background) {
+       if (!req->background) {
+               wake_up(&req->waitq);
+               fuse_put_request_locked(fc, req);
+               spin_unlock(&fuse_lock);
+       } else {
+               void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
+               req->end = NULL;
+               spin_unlock(&fuse_lock);

                down_read(&fc->sbput_sem);
                if (fc->mounted)
                        fuse_release_background(req);
                up_read(&fc->sbput_sem);
                down_read(&fc->sbput_sem);
                if (fc->mounted)
                        fuse_release_background(req);
                up_read(&fc->sbput_sem);

+               if (end)
+                       end(fc, req);
+               else
+                       fuse_put_request(fc, req);

        }
        }

-       wake_up(&req->waitq);
-       if (end)
-               end(fc, req);
-       else
-               fuse_put_request(fc, req);

 }
 
 /*
 }
 
 /*


@@ -898,7 +922,7 @@ static int fuse_dev_release(struct inode *inode, struct file *file)
        return 0;
 }
 
        return 0;
 }
 

-struct file_operations fuse_dev_operations = {
+const struct file_operations fuse_dev_operations = {

        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .read           = fuse_dev_read,
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .read           = fuse_dev_read,