Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757285AbZDBPcb (ORCPT ); Thu, 2 Apr 2009 11:32:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751232AbZDBPcT (ORCPT ); Thu, 2 Apr 2009 11:32:19 -0400 Received: from mx2.redhat.com ([66.187.237.31]:49322 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbZDBPcS (ORCPT ); Thu, 2 Apr 2009 11:32:18 -0400 Message-ID: <49D4DA7E.7010508@redhat.com> Date: Thu, 02 Apr 2009 11:32:14 -0400 From: Peter Staubach User-Agent: Thunderbird 1.5.0.12 (X11/20080915) MIME-Version: 1.0 To: David Howells CC: viro@ZenIV.linux.org.uk, linux-fsdevel@vger.kernel.org, nfsv4@linux-nfs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 22/43] CacheFiles: Add a hook to write a single page of data to an inode [ver #46] References: <20090401230321.28177.12010.stgit@warthog.procyon.org.uk> <20090401230515.28177.73948.stgit@warthog.procyon.org.uk> In-Reply-To: <20090401230515.28177.73948.stgit@warthog.procyon.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6794 Lines: 184 David Howells wrote: > Add an address space operation to write one single page of data to an inode at > a page-aligned location (thus permitting the implementation to be highly > optimised). The data source is a single page. > > This is used by CacheFiles to store the contents of netfs pages into their > backing file pages. > > Supply a generic implementation for this that uses the write_begin() and > write_end() address_space operations to bind a copy directly into the page > cache. > > Hook the Ext2 and Ext3 operations to the generic implementation. > > Signed-off-by: David Howells > Acked-by: Steve Dickson > Acked-by: Trond Myklebust > --- > > fs/ext2/inode.c | 2 ++ > fs/ext3/inode.c | 3 +++ > include/linux/fs.h | 7 ++++++ > mm/filemap.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 73 insertions(+), 0 deletions(-) > > > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c > index b43b955..5d17070 100644 > --- a/fs/ext2/inode.c > +++ b/fs/ext2/inode.c > @@ -817,6 +817,8 @@ const struct address_space_operations ext2_nobh_aops = { > .direct_IO = ext2_direct_IO, > .writepages = ext2_writepages, > .migratepage = buffer_migrate_page, > + .write_one_page = generic_file_buffered_write_one_page, > + .write_one_page = generic_file_buffered_write_one_page, > You probably only need one of these lines, don't you? Thanx... ps > }; > > /* > diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c > index d897033..a2e5fef 100644 > --- a/fs/ext3/inode.c > +++ b/fs/ext3/inode.c > @@ -1803,6 +1803,7 @@ static const struct address_space_operations ext3_ordered_aops = { > .direct_IO = ext3_direct_IO, > .migratepage = buffer_migrate_page, > .is_partially_uptodate = block_is_partially_uptodate, > + .write_one_page = generic_file_buffered_write_one_page, > }; > > static const struct address_space_operations ext3_writeback_aops = { > @@ -1818,6 +1819,7 @@ static const struct address_space_operations ext3_writeback_aops = { > .direct_IO = ext3_direct_IO, > .migratepage = buffer_migrate_page, > .is_partially_uptodate = block_is_partially_uptodate, > + .write_one_page = generic_file_buffered_write_one_page, > }; > > static const struct address_space_operations ext3_journalled_aops = { > @@ -1832,6 +1834,7 @@ static const struct address_space_operations ext3_journalled_aops = { > .invalidatepage = ext3_invalidatepage, > .releasepage = ext3_releasepage, > .is_partially_uptodate = block_is_partially_uptodate, > + .write_one_page = generic_file_buffered_write_one_page, > }; > > void ext3_set_aops(struct inode *inode) > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 61211ad..df93cdf 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -532,6 +532,11 @@ struct address_space_operations { > int (*launder_page) (struct page *); > int (*is_partially_uptodate) (struct page *, read_descriptor_t *, > unsigned long); > + > + /* write the contents of the source page over the page at the specified > + * index in the target address space (the source page does not need to > + * be related to the target address space) */ > + int (*write_one_page)(struct address_space *, pgoff_t, struct page *); > }; > > /* > @@ -2119,6 +2124,8 @@ extern ssize_t generic_file_direct_write(struct kiocb *, const struct iovec *, > unsigned long *, loff_t, loff_t *, size_t, size_t); > extern ssize_t generic_file_buffered_write(struct kiocb *, const struct iovec *, > unsigned long, loff_t, loff_t *, size_t, ssize_t); > +extern int generic_file_buffered_write_one_page(struct address_space *, > + pgoff_t, struct page *); > extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos); > extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos); > extern int generic_segment_checks(const struct iovec *iov, > diff --git a/mm/filemap.c b/mm/filemap.c > index 3c55c1a..d766c2f 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2320,6 +2320,67 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, > } > EXPORT_SYMBOL(generic_file_buffered_write); > > +/** > + * generic_file_buffered_write_one_page - Write a single page of data to an > + * inode > + * @mapping - The address space of the target inode > + * @index - The target page in the target inode to fill > + * @source - The data to write into the target page > + * > + * Write the data from the source page to the page in the nominated address > + * space at the @index specified. Note that the file will not be extended if > + * the page crosses the EOF marker, in which case only the first part of the > + * page will be written. > + * > + * The @source page does not need to have any association with the file or the > + * target page offset. > + */ > +int generic_file_buffered_write_one_page(struct address_space *mapping, > + pgoff_t index, > + struct page *source) > +{ > + const struct address_space_operations *a_ops = mapping->a_ops; > + struct page *page; > + unsigned len; > + loff_t isize, pos; > + void *fsdata; > + int ret; > + > + pos = index; > + pos <<= PAGE_CACHE_SHIFT; > + > + len = PAGE_CACHE_SIZE; > + isize = i_size_read(mapping->host); > + if ((isize >> PAGE_CACHE_SHIFT) == index) > + len = isize & (PAGE_CACHE_SIZE - 1); > + > + ret = pagecache_write_begin(NULL, mapping, pos, len, > + AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); > + if (ret < 0) > + goto sync; > + > + copy_highpage(page, source); > + > + ret = pagecache_write_end(NULL, mapping, pos, len, len, page, fsdata); > + if (ret < 0) > + goto sync; > + > + balance_dirty_pages_ratelimited(mapping); > + cond_resched(); > + > +sync: > + /* the caller must handle O_SYNC themselves, but we handle S_SYNC and > + * MS_SYNCHRONOUS here */ > + if (unlikely(IS_SYNC(mapping->host)) && !a_ops->writepage) > + ret = generic_osync_inode(mapping->host, mapping, > + OSYNC_METADATA | OSYNC_DATA); > + > + /* the caller must handle O_DIRECT for themselves */ > + > + return ret; > +} > +EXPORT_SYMBOL(generic_file_buffered_write_one_page); > + > static ssize_t > __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, > unsigned long nr_segs, loff_t *ppos) > > _______________________________________________ > NFSv4 mailing list > NFSv4@linux-nfs.org > http://linux-nfs.org/cgi-bin/mailman/listinfo/nfsv4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/