Messages in this thread | | | Date | Fri, 23 Mar 2012 15:45:02 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 01/19] mm: Make default vm_ops provide ->page_mkwrite handler |
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On Mon, 5 Mar 2012 17:00:59 +0100 Jan Kara <jack@suse.cz> wrote:
> --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -1759,8 +1759,28 @@ page_not_uptodate: > } > EXPORT_SYMBOL(filemap_fault); > > +int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > +{ > + struct page *page = vmf->page; > + struct inode *inode = vma->vm_file->f_path.dentry->d_inode; > + int ret = VM_FAULT_LOCKED; > + > + file_update_time(vma->vm_file); > + lock_page(page); > + if ((page->mapping != inode->i_mapping) || > + (page_offset(page) > i_size_read(inode))) {
Would benefit from a comment explaining how the page can come to be outside i_size, and why we fail in that case.
I don't think i_mutex is held here, so this test is rather meaningless and racy anyway?
> + unlock_page(page); > + ret = VM_FAULT_NOPAGE; > + goto out; > + } > +out: > + return ret; > +} > +EXPORT_SYMBOL(filemap_page_mkwrite);
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