[Linux-cluster] Re: GFS
Pekka J Enberg
penberg at cs.helsinki.fi
Mon Aug 8 14:14:45 UTC 2005
David Teigland writes:
> +static ssize_t walk_vm_hard(struct file *file, char *buf, size_t size,
> + loff_t *offset, do_rw_t operation)
> +{
> + struct gfs2_holder *ghs;
> + unsigned int num_gh = 0;
> + ssize_t count;
> +
> + {
Can we please get rid of the extra braces everywhere?
[snip]
David Teigland writes:
> +
> + for (vma = find_vma(mm, start); vma; vma = vma->vm_next) {
> + if (end <= vma->vm_start)
> + break;
> + if (vma->vm_file &&
> + vma->vm_file->f_dentry->d_inode->i_sb == sb) {
> + num_gh++;
> + }
> + }
> +
> + ghs = kmalloc((num_gh + 1) * sizeof(struct gfs2_holder),
> + GFP_KERNEL);
> + if (!ghs) {
> + if (!dumping)
> + up_read(&mm->mmap_sem);
> + return -ENOMEM;
> + }
> +
> + for (vma = find_vma(mm, start); vma; vma = vma->vm_next) {
Sorry if this is an obvious question but what prevents another thread from
doing mmap() before we do the second walk and messing up num_gh?
> + if (end <= vma->vm_start)
> + break;
> + if (vma->vm_file) {
> + struct inode *inode;
> + inode = vma->vm_file->f_dentry->d_inode;
> + if (inode->i_sb == sb)
> + gfs2_holder_init(get_v2ip(inode)->i_gl,
> + vma2state(vma),
> + 0, &ghs[x++]);
> + }
> + }
Pekka
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