fuse: move fget() to fuse_get_tree()

Affected call chains:

fuse_get_tree
   -> get_tree_(bdev|nodev)
      -> fuse_fill_super

Needed for following patch.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 07829ce..a784809 100644 (file)
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -489,6 +489,7 @@ struct fuse_dev {
 
 struct fuse_fs_context {
        int fd;
+       struct file *file;
        unsigned int rootmode;
        kuid_t user_id;
        kgid_t group_id;

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 54379a0..3d64a68 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1509,38 +1509,33 @@ EXPORT_SYMBOL_GPL(fuse_fill_super_common);
 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
 {
        struct fuse_fs_context *ctx = fsc->fs_private;
-       struct file *file;
        int err;
        struct fuse_conn *fc;
        struct fuse_mount *fm;
 
-       if (!ctx->fd_present || !ctx->rootmode_present ||
+       if (!ctx->file || !ctx->rootmode_present ||
            !ctx->user_id_present || !ctx->group_id_present)
                return -EINVAL;
 
-       err = -EINVAL;
-       file = fget(ctx->fd);
-       if (!file)
-               goto err;
-
        /*
         * Require mount to happen from the same user namespace which
         * opened /dev/fuse to prevent potential attacks.
         */
-       if ((file->f_op != &fuse_dev_operations) ||
-           (file->f_cred->user_ns != sb->s_user_ns))
-               goto err_fput;
-       ctx->fudptr = &file->private_data;
+       err = -EINVAL;
+       if ((ctx->file->f_op != &fuse_dev_operations) ||
+           (ctx->file->f_cred->user_ns != sb->s_user_ns))
+               goto err;
+       ctx->fudptr = &ctx->file->private_data;
 
        fc = kmalloc(sizeof(*fc), GFP_KERNEL);
        err = -ENOMEM;
        if (!fc)
-               goto err_fput;
+               goto err;
 
        fm = kzalloc(sizeof(*fm), GFP_KERNEL);
        if (!fm) {
                kfree(fc);
-               goto err_fput;
+               goto err;
        }
 
        fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
@@ -1551,12 +1546,8 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
        err = fuse_fill_super_common(sb, ctx);
        if (err)
                goto err_put_conn;
-       /*
-        * atomic_dec_and_test() in fput() provides the necessary
-        * memory barrier for file->private_data to be visible on all
-        * CPUs after this
-        */
-       fput(file);
+       /* file->private_data shall be visible on all CPUs after this */
+       smp_mb();
        fuse_send_init(get_fuse_mount_super(sb));
        return 0;
 
@@ -1564,8 +1555,6 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
        fuse_conn_put(fc);
        kfree(fm);
        sb->s_fs_info = NULL;
- err_fput:
-       fput(file);
  err:
        return err;
 }
@@ -1573,12 +1562,21 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
 static int fuse_get_tree(struct fs_context *fsc)
 {
        struct fuse_fs_context *ctx = fsc->fs_private;
+       int err;
+
+       if (ctx->fd_present)
+               ctx->file = fget(ctx->fd);
 
        if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
-               return get_tree_bdev(fsc, fuse_fill_super);
+               err = get_tree_bdev(fsc, fuse_fill_super);
+               goto out_fput;
        }
 
-       return get_tree_nodev(fsc, fuse_fill_super);
+       err = get_tree_nodev(fsc, fuse_fill_super);
+out_fput:
+       if (ctx->file)
+               fput(ctx->file);
+       return err;
 }
 
 static const struct fs_context_operations fuse_context_ops = {