From patchwork Fri Jun 24 18:29:40 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 101863 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 6E180B6F88 for ; Sat, 25 Jun 2011 04:32:59 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752088Ab1FXScs (ORCPT ); Fri, 24 Jun 2011 14:32:48 -0400 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:56820 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752277Ab1FXScO (ORCPT ); Fri, 24 Jun 2011 14:32:14 -0400 Received: from hch by bombadil.infradead.org with local (Exim 4.76 #1 (Red Hat Linux)) id 1QaBAk-0001gw-Uc; Fri, 24 Jun 2011 18:32:07 +0000 Message-Id: <20110624183206.880957697@bombadil.infradead.org> User-Agent: quilt/0.48-1 Date: Fri, 24 Jun 2011 14:29:40 -0400 From: Christoph Hellwig To: viro@zeniv.linux.org.uk, tglx@linutronix.de Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, hirofumi@mail.parknet.co.jp, mfasheh@suse.com, jlbec@evilplan.org Subject: [PATCH 1/9] fat: remove i_alloc_sem abuse References: <20110624182939.401012221@bombadil.infradead.org> Content-Disposition: inline; filename=fat-avoid-i_alloc_sem X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Add a new rw_semaphore to protect bmap against truncate. Previous i_alloc_sem was abused for this, but it's going away in this series. Note that we can't simply use i_mutex, given that the swapon code calls ->bmap under it. Signed-off-by: Christoph Hellwig --- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-2.6/fs/fat/inode.c =================================================================== --- linux-2.6.orig/fs/fat/inode.c 2011-06-20 21:28:19.707963855 +0200 +++ linux-2.6/fs/fat/inode.c 2011-06-20 21:29:25.031293882 +0200 @@ -224,9 +224,9 @@ static sector_t _fat_bmap(struct address sector_t blocknr; /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ - down_read(&mapping->host->i_alloc_sem); + down_read(&MSDOS_I(mapping->host)->truncate_lock); blocknr = generic_block_bmap(mapping, block, fat_get_block); - up_read(&mapping->host->i_alloc_sem); + up_read(&MSDOS_I(mapping->host)->truncate_lock); return blocknr; } @@ -510,6 +510,8 @@ static struct inode *fat_alloc_inode(str ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); if (!ei) return NULL; + + init_rwsem(&ei->truncate_lock); return &ei->vfs_inode; } Index: linux-2.6/fs/fat/fat.h =================================================================== --- linux-2.6.orig/fs/fat/fat.h 2011-06-20 21:28:19.724630522 +0200 +++ linux-2.6/fs/fat/fat.h 2011-06-20 21:29:25.034627215 +0200 @@ -109,6 +109,7 @@ struct msdos_inode_info { int i_attrs; /* unused attribute bits */ loff_t i_pos; /* on-disk position of directory entry or 0 */ struct hlist_node i_fat_hash; /* hash by i_location */ + struct rw_semaphore truncate_lock; /* protect bmap against truncate */ struct inode vfs_inode; }; Index: linux-2.6/fs/fat/file.c =================================================================== --- linux-2.6.orig/fs/fat/file.c 2011-06-20 21:28:19.744630521 +0200 +++ linux-2.6/fs/fat/file.c 2011-06-20 21:29:54.501292390 +0200 @@ -429,8 +429,10 @@ int fat_setattr(struct dentry *dentry, s } if (attr->ia_valid & ATTR_SIZE) { + down_write(&MSDOS_I(inode)->truncate_lock); truncate_setsize(inode, attr->ia_size); fat_truncate_blocks(inode, attr->ia_size); + up_write(&MSDOS_I(inode)->truncate_lock); } setattr_copy(inode, attr);