From: Mingming Cao Subject: Re: [PATCH -v2] ext4: Use page_mkwrite vma_operations to get mmap write notification. Date: Mon, 18 Feb 2008 21:25:43 -0800 Message-ID: <1203398743.3612.11.camel@localhost.localdomain> References: <1203392640-14335-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Reply-To: cmm@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: tytso@mit.edu, linux-ext4@vger.kernel.org To: "Aneesh Kumar K.V" Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:58868 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751158AbYBSFZu (ORCPT ); Tue, 19 Feb 2008 00:25:50 -0500 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e2.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id m1J5PnAb027923 for ; Tue, 19 Feb 2008 00:25:49 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m1J5Pnll368912 for ; Tue, 19 Feb 2008 00:25:49 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m1J5Pn7D024638 for ; Tue, 19 Feb 2008 00:25:49 -0500 In-Reply-To: <1203392640-14335-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, 2008-02-19 at 09:13 +0530, Aneesh Kumar K.V wrote: > We would like to get notified when we are doing a write on mmap section. > This is needed with respect to preallocated area. We split the preallocated > area into initialzed extent and uninitialzed extent in the call back. This > let us handle ENOSPC better. Otherwise we get ENOSPC in the writepage and > that would result in data loss. The changes are also needed to handle ENOSPC > when writing to an mmap section of files with holes. > Acked. Added to patch queue. Thanks, Mingming > Signed-off-by: Aneesh Kumar K.V > --- > fs/ext4/file.c | 19 ++++++++++++++++++- > fs/ext4/inode.c | 6 ++++++ > include/linux/ext4_fs.h | 1 + > 3 files changed, 25 insertions(+), 1 deletions(-) > > diff --git a/fs/ext4/file.c b/fs/ext4/file.c > index 20507a2..77341c1 100644 > --- a/fs/ext4/file.c > +++ b/fs/ext4/file.c > @@ -123,6 +123,23 @@ force_commit: > return ret; > } > > +static struct vm_operations_struct ext4_file_vm_ops = { > + .fault = filemap_fault, > + .page_mkwrite = ext4_page_mkwrite, > +}; > + > +static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma) > +{ > + struct address_space *mapping = file->f_mapping; > + > + if (!mapping->a_ops->readpage) > + return -ENOEXEC; > + file_accessed(file); > + vma->vm_ops = &ext4_file_vm_ops; > + vma->vm_flags |= VM_CAN_NONLINEAR; > + return 0; > +} > + > const struct file_operations ext4_file_operations = { > .llseek = generic_file_llseek, > .read = do_sync_read, > @@ -133,7 +150,7 @@ const struct file_operations ext4_file_operations = { > #ifdef CONFIG_COMPAT > .compat_ioctl = ext4_compat_ioctl, > #endif > - .mmap = generic_file_mmap, > + .mmap = ext4_file_mmap, > .open = generic_file_open, > .release = ext4_release_file, > .fsync = ext4_sync_file, > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 34f3eb6..81faa67 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3466,3 +3466,9 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val) > > return err; > } > + > +int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page) > +{ > + return block_page_mkwrite(vma, page, ext4_get_block); > +} > + > diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h > index 22810b1..8f5a563 100644 > --- a/include/linux/ext4_fs.h > +++ b/include/linux/ext4_fs.h > @@ -1059,6 +1059,7 @@ extern void ext4_set_aops(struct inode *inode); > extern int ext4_writepage_trans_blocks(struct inode *); > extern int ext4_block_truncate_page(handle_t *handle, struct page *page, > struct address_space *mapping, loff_t from); > +extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page); > > /* ioctl.c */ > extern long ext4_ioctl(struct file *, unsigned int, unsigned long);