From: Jan Kara Subject: [PATCH 3/4] ext4: Make sure blocks are properly allocated under mmaped page even when blocksize < pagesize Date: Wed, 29 Apr 2009 12:02:49 +0200 Message-ID: <1240999370-27502-4-git-send-email-jack@suse.cz> References: <1240999370-27502-1-git-send-email-jack@suse.cz> Cc: linux-fsdevel@vger.kernel.org, npiggin@suse.de, Jan Kara To: linux-ext4@vger.kernel.org Return-path: Received: from cantor.suse.de ([195.135.220.2]:55077 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753309AbZD2KCw (ORCPT ); Wed, 29 Apr 2009 06:02:52 -0400 In-Reply-To: <1240999370-27502-1-git-send-email-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: In a situation like: truncate(f, 1024); a = mmap(f, 0, 4096); a[0] = 'a'; truncate(f, 4096); we end up with a dirty page which does not have all blocks allocated / reserved. Fix the problem by using new VFS infrastructure. Signed-off-by: Jan Kara --- fs/ext4/inode.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c6bd6ce..8f51219 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3363,6 +3363,7 @@ static const struct address_space_operations ext4_ordered_aops = { .sync_page = block_sync_page, .write_begin = ext4_write_begin, .write_end = ext4_ordered_write_end, + .extend_i_size = block_extend_i_size, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, @@ -3378,6 +3379,7 @@ static const struct address_space_operations ext4_writeback_aops = { .sync_page = block_sync_page, .write_begin = ext4_write_begin, .write_end = ext4_writeback_write_end, + .extend_i_size = block_extend_i_size, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, @@ -3393,6 +3395,7 @@ static const struct address_space_operations ext4_journalled_aops = { .sync_page = block_sync_page, .write_begin = ext4_write_begin, .write_end = ext4_journalled_write_end, + .extend_i_size = block_extend_i_size, .set_page_dirty = ext4_journalled_set_page_dirty, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, @@ -3408,6 +3411,7 @@ static const struct address_space_operations ext4_da_aops = { .sync_page = block_sync_page, .write_begin = ext4_da_write_begin, .write_end = ext4_da_write_end, + .extend_i_size = block_extend_i_size, .bmap = ext4_bmap, .invalidatepage = ext4_da_invalidatepage, .releasepage = ext4_releasepage, @@ -5260,6 +5264,12 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) struct address_space *mapping = inode->i_mapping; /* + * Wait for extending of i_size, after this moment, next truncate / + * write can create holes under us but they writeprotect our page so + * we'll be called again to fill the hole. + */ + block_wait_on_hole_extend(inode, page_offset(page)); + /* * Get i_alloc_sem to stop truncates messing with the inode. We cannot * get i_mutex because we are already holding mmap_sem. */ -- 1.6.0.2