fuse: update fuse_conn_init() and separate out fuse_conn_kill()

Update fuse_conn_init() such that it doesn't take @sb and move bdi
registration into a separate function.  Also separate out
fuse_conn_kill() from fuse_put_super().

These will be used to implement cuse.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

3 files changed, 72 insertions, 53 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ba76b68c52ff..368189fd4056 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -282,7 +282,7 @@ __releases(&fc->lock)
                         wake_up_all(&fc->blocked_waitq);
                 }
                 if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&
-                    fc->connected) {
+                    fc->connected && fc->bdi_initialized) {
                         clear_bdi_congested(&fc->bdi, READ);
                         clear_bdi_congested(&fc->bdi, WRITE);
                 }
@@ -408,7 +408,8 @@ static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
         fc->num_background++;
         if (fc->num_background == FUSE_MAX_BACKGROUND)
                 fc->blocked = 1;
-        if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
+        if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&
+            fc->bdi_initialized) {
                 set_bdi_congested(&fc->bdi, READ);
                 set_bdi_congested(&fc->bdi, WRITE);
         }
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index ef2e1f3780b5..2efcf12b763a 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -394,6 +394,9 @@ struct fuse_conn {
         /** Filesystem supports NFS exporting.  Only set in INIT */
         unsigned export_support:1;
 
+        /** Set if bdi is valid */
+        unsigned bdi_initialized:1;
+
         /*
          * The following bitfields are only for optimization purposes
          * and hence races in setting them will not cause malfunction
@@ -662,7 +665,7 @@ struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 /**
  * Initialize fuse_conn
  */
-int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb);
+void fuse_conn_init(struct fuse_conn *fc);
 
 /**
  * Release reference to fuse_conn
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 75ca5ac603ae..fea7c1064d30 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -274,11 +274,14 @@ static void fuse_send_destroy(struct fuse_conn *fc)
         }
 }
 
-static void fuse_put_super(struct super_block *sb)
+static void fuse_bdi_destroy(struct fuse_conn *fc)
 {
-        struct fuse_conn *fc = get_fuse_conn_super(sb);
+        if (fc->bdi_initialized)
+                bdi_destroy(&fc->bdi);
+}
 
-        fuse_send_destroy(fc);
+static void fuse_conn_kill(struct fuse_conn *fc)
+{
         spin_lock(&fc->lock);
         fc->connected = 0;
         fc->blocked = 0;
@@ -292,7 +295,15 @@ static void fuse_put_super(struct super_block *sb)
         list_del(&fc->entry);
         fuse_ctl_remove_conn(fc);
         mutex_unlock(&fuse_mutex);
-        bdi_destroy(&fc->bdi);
+        fuse_bdi_destroy(fc);
+}
+
+static void fuse_put_super(struct super_block *sb)
+{
+        struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+        fuse_send_destroy(fc);
+        fuse_conn_kill(fc);
         fuse_conn_put(fc);
 }
 
@@ -463,10 +474,8 @@ static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
         return 0;
 }
 
-int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb)
+void fuse_conn_init(struct fuse_conn *fc)
 {
-        int err;
-
         memset(fc, 0, sizeof(*fc));
         spin_lock_init(&fc->lock);
         mutex_init(&fc->inst_mutex);
@@ -481,49 +490,12 @@ int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb)
         INIT_LIST_HEAD(&fc->bg_queue);
         INIT_LIST_HEAD(&fc->entry);
         atomic_set(&fc->num_waiting, 0);
-        fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
-        fc->bdi.unplug_io_fn = default_unplug_io_fn;
-        /* fuse does it's own writeback accounting */
-        fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
         fc->khctr = 0;
         fc->polled_files = RB_ROOT;
-        fc->dev = sb->s_dev;
-        err = bdi_init(&fc->bdi);
-        if (err)
-                goto error_mutex_destroy;
-        if (sb->s_bdev) {
-                err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
-                                   MAJOR(fc->dev), MINOR(fc->dev));
-        } else {
-                err = bdi_register_dev(&fc->bdi, fc->dev);
-        }
-        if (err)
-                goto error_bdi_destroy;
-        /*
-         * For a single fuse filesystem use max 1% of dirty +
-         * writeback threshold.
-         *
-         * This gives about 1M of write buffer for memory maps on a
-         * machine with 1G and 10% dirty_ratio, which should be more
-         * than enough.
-         *
-         * Privileged users can raise it by writing to
-         *
-         *    /sys/class/bdi/<bdi>/max_ratio
-         */
-        bdi_set_max_ratio(&fc->bdi, 1);
         fc->reqctr = 0;
         fc->blocked = 1;
         fc->attr_version = 1;
         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
-
-        return 0;
-
- error_bdi_destroy:
-        bdi_destroy(&fc->bdi);
- error_mutex_destroy:
-        mutex_destroy(&fc->inst_mutex);
-        return err;
 }
 EXPORT_SYMBOL_GPL(fuse_conn_init);
 
@@ -794,6 +766,48 @@ static void fuse_free_conn(struct fuse_conn *fc)
         kfree(fc);
 }
 
+static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
+{
+        int err;
+
+        fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
+        fc->bdi.unplug_io_fn = default_unplug_io_fn;
+        /* fuse does it's own writeback accounting */
+        fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
+
+        err = bdi_init(&fc->bdi);
+        if (err)
+                return err;
+
+        fc->bdi_initialized = 1;
+
+        if (sb->s_bdev) {
+                err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
+                                    MAJOR(fc->dev), MINOR(fc->dev));
+        } else {
+                err = bdi_register_dev(&fc->bdi, fc->dev);
+        }
+
+        if (err)
+                return err;
+
+        /*
+         * For a single fuse filesystem use max 1% of dirty +
+         * writeback threshold.
+         *
+         * This gives about 1M of write buffer for memory maps on a
+         * machine with 1G and 10% dirty_ratio, which should be more
+         * than enough.
+         *
+         * Privileged users can raise it by writing to
+         *
+         *    /sys/class/bdi/<bdi>/max_ratio
+         */
+        bdi_set_max_ratio(&fc->bdi, 1);
+
+        return 0;
+}
+
 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 {
         struct fuse_conn *fc;
@@ -840,11 +854,12 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
         if (!fc)
                 goto err_fput;
 
-        err = fuse_conn_init(fc, sb);
-        if (err) {
-                kfree(fc);
-                goto err_fput;
-        }
+        fuse_conn_init(fc);
+
+        fc->dev = sb->s_dev;
+        err = fuse_bdi_init(fc, sb);
+        if (err)
+                goto err_put_conn;
 
         fc->release = fuse_free_conn;
         fc->flags = d.flags;
@@ -908,7 +923,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
  err_put_root:
         dput(root_dentry);
  err_put_conn:
-        bdi_destroy(&fc->bdi);
+        fuse_bdi_destroy(fc);
         fuse_conn_put(fc);
  err_fput:
         fput(file);