From: Jan Kara Subject: [PATCH 08/11] vfs: Unmap underlying metadata of new data buffers only when buffer is mapped Date: Wed, 27 May 2009 15:01:05 +0200 Message-ID: <1243429268-3028-9-git-send-email-jack@suse.cz> References: <1243429268-3028-1-git-send-email-jack@suse.cz> Cc: npiggin@suse.de, linux-ext4@vger.kernel.org, Jan Kara To: LKML Return-path: Received: from cantor2.suse.de ([195.135.220.15]:47973 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763071AbZE0NBJ (ORCPT ); Wed, 27 May 2009 09:01:09 -0400 In-Reply-To: <1243429268-3028-1-git-send-email-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: When we do delayed allocation of some buffer, we want to signal to VFS that the buffer is new (set buffer_new) so that it properly zeros out everything. But we don't have the buffer mapped yet so we cannot really unmap underlying metadata in this state. Make VFS avoid doing unmapping of metadata when the buffer is not yet mapped. Signed-off-by: Jan Kara --- fs/buffer.c | 12 +++++++----- 1 files changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index ddfcade..3d0bced 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1683,8 +1683,9 @@ static int __block_write_full_page(struct inode *inode, struct page *page, if (buffer_new(bh)) { /* blockdev mappings never come here */ clear_buffer_new(bh); - unmap_underlying_metadata(bh->b_bdev, - bh->b_blocknr); + if (buffer_mapped(bh)) + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); } } bh = bh->b_this_page; @@ -1869,8 +1870,9 @@ static int __block_prepare_write(struct inode *inode, struct page *page, if (err) break; if (buffer_new(bh)) { - unmap_underlying_metadata(bh->b_bdev, - bh->b_blocknr); + if (buffer_mapped(bh)) + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); if (PageUptodate(page)) { clear_buffer_new(bh); set_buffer_uptodate(bh); @@ -2683,7 +2685,7 @@ int nobh_write_begin(struct file *file, struct address_space *mapping, goto failed; if (!buffer_mapped(bh)) is_mapped_to_disk = 0; - if (buffer_new(bh)) + if (buffer_new(bh) && buffer_mapped(bh)) unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); if (PageUptodate(page)) { set_buffer_uptodate(bh); -- 1.6.0.2