diff options
Diffstat (limited to 'fs/kernfs/file.c')
| -rw-r--r-- | fs/kernfs/file.c | 48 |
1 files changed, 42 insertions, 6 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index aaa76410e550..8502ef68459b 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -447,7 +447,7 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma) * warnings and we don't want to add spurious locking dependency * between the two. Check whether mmap is actually implemented * without grabbing @of->mutex by testing HAS_MMAP flag. See the - * comment in kernfs_file_open() for more details. + * comment in kernfs_fop_open() for more details. */ if (!(of->kn->flags & KERNFS_HAS_MMAP)) return -ENODEV; @@ -483,9 +483,11 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma) goto out_put; rc = 0; - of->mmapped = true; - of_on(of)->nr_mmapped++; - of->vm_ops = vma->vm_ops; + if (!of->mmapped) { + of->mmapped = true; + of_on(of)->nr_mmapped++; + of->vm_ops = vma->vm_ops; + } vma->vm_ops = &kernfs_vm_ops; out_put: kernfs_put_active(of->kn); @@ -634,11 +636,18 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) * each file a separate locking class. Let's differentiate on * whether the file has mmap or not for now. * - * Both paths of the branch look the same. They're supposed to + * For similar reasons, writable and readonly files are given different + * lockdep key, because the writable file /sys/power/resume may call vfs + * lookup helpers for arbitrary paths and readonly files can be read by + * overlayfs from vfs helpers when sysfs is a lower layer of overalyfs. + * + * All three cases look the same. They're supposed to * look that way and give @of->mutex different static lockdep keys. */ if (has_mmap) mutex_init(&of->mutex); + else if (file->f_mode & FMODE_WRITE) + mutex_init(&of->mutex); else mutex_init(&of->mutex); @@ -854,6 +863,33 @@ static __poll_t kernfs_fop_poll(struct file *filp, poll_table *wait) return ret; } +static loff_t kernfs_fop_llseek(struct file *file, loff_t offset, int whence) +{ + struct kernfs_open_file *of = kernfs_of(file); + const struct kernfs_ops *ops; + loff_t ret; + + /* + * @of->mutex nests outside active ref and is primarily to ensure that + * the ops aren't called concurrently for the same open file. + */ + mutex_lock(&of->mutex); + if (!kernfs_get_active(of->kn)) { + mutex_unlock(&of->mutex); + return -ENODEV; + } + + ops = kernfs_ops(of->kn); + if (ops->llseek) + ret = ops->llseek(of, offset, whence); + else + ret = generic_file_llseek(file, offset, whence); + + kernfs_put_active(of->kn); + mutex_unlock(&of->mutex); + return ret; +} + static void kernfs_notify_workfn(struct work_struct *work) { struct kernfs_node *kn; @@ -956,7 +992,7 @@ EXPORT_SYMBOL_GPL(kernfs_notify); const struct file_operations kernfs_file_fops = { .read_iter = kernfs_fop_read_iter, .write_iter = kernfs_fop_write_iter, - .llseek = generic_file_llseek, + .llseek = kernfs_fop_llseek, .mmap = kernfs_fop_mmap, .open = kernfs_fop_open, .release = kernfs_fop_release, |