Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753451AbbESFvX (ORCPT ); Tue, 19 May 2015 01:51:23 -0400 Received: from mail.kernel.org ([198.145.29.136]:54438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750982AbbESFvW (ORCPT ); Tue, 19 May 2015 01:51:22 -0400 Date: Mon, 18 May 2015 22:51:19 -0700 From: Jaegeuk Kim To: Chao Yu Cc: Changman Lee , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] f2fs: support RENAME_WHITEOUT Message-ID: <20150519055119.GA39478@jaegeuk-mac02.hsd1.ca.comcast.net> References: <002e01d0912f$30fc5cc0$92f51640$@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <002e01d0912f$30fc5cc0$92f51640$@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7703 Lines: 246 Hi Chao, On Mon, May 18, 2015 at 01:54:22PM +0800, Chao Yu wrote: > As the description of rename in manual, RENAME_WHITEOUT is a special operation > that only makes sense for overlay/union type filesystem. > > When performing rename with RENAME_WHITEOUT, dst will be replace with src, and > meanwhile, a 'whiteout' will be create with name of src. > > A "whiteout" is designed to be a char device with 0,0 device number, it has > specially meaning for stackable filesystem. In these filesystems, there are > multiple layers exist, and only top of these can be modified. So a whiteout > in top layer is used to hide a corresponding file in lower layer, as well > removal of whiteout will make the file appear. > > Now in overlayfs, when we rename a file which is exist in lower layer, it > will be copied up to upper if it is not on upper layer yet, and then rename > it on upper layer, source file will be whiteouted to hide corresponding file > in lower layer at the same time. > > So in upper layer filesystem, implementation of RENAME_WHITEOUT provide a > atomic operation for stackable filesystem to support rename operation. > > There are multiple ways to implement RENAME_WHITEOUT in log of this commit: > 7dcf5c3e4527 ("xfs: add RENAME_WHITEOUT support") which pointed out by > Dave Chinner. > > For now, we just try to follow the way that xfs/ext4 use. Could you merge the two patches into one? And, after finishing xfstests, kernel reports missing inode objects. Could you check it out? I didn't take a closer look at it. > > Signed-off-by: Chao Yu > --- > fs/f2fs/namei.c | 140 ++++++++++++++++++++++++++++++++++++-------------------- > 1 file changed, 90 insertions(+), 50 deletions(-) > > diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c > index 16b74da..bed0cb0 100644 > --- a/fs/f2fs/namei.c > +++ b/fs/f2fs/namei.c > @@ -510,14 +510,80 @@ out: > return err; > } > > +static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry, > + umode_t mode, struct inode **whiteout) > +{ > + struct f2fs_sb_info *sbi = F2FS_I_SB(dir); > + struct inode *inode; > + int err; > + > + inode = f2fs_new_inode(dir, mode); > + if (IS_ERR(inode)) > + return PTR_ERR(inode); > + > + if (whiteout) { > + init_special_inode(inode, inode->i_mode, WHITEOUT_DEV); > + inode->i_op = &f2fs_special_inode_operations; > + } else { > + inode->i_op = &f2fs_file_inode_operations; > + inode->i_fop = &f2fs_file_operations; > + inode->i_mapping->a_ops = &f2fs_dblock_aops; > + } > + > + f2fs_lock_op(sbi); > + err = acquire_orphan_inode(sbi); > + if (err) > + goto out; > + > + err = f2fs_do_tmpfile(inode, dir); > + if (err) > + goto release_out; > + > + /* > + * add this non-linked tmpfile to orphan list, in this way we could > + * remove all unused data of tmpfile after abnormal power-off. > + */ > + add_orphan_inode(sbi, inode->i_ino); > + f2fs_unlock_op(sbi); > + > + alloc_nid_done(sbi, inode->i_ino); > + > + if (whiteout) { > + inode_dec_link_count(inode); Maybe due to this? We don't need to decrease its link count? Thanks, > + *whiteout = inode; > + } else { > + d_tmpfile(dentry, inode); > + } > + unlock_new_inode(inode); > + return 0; > + > +release_out: > + release_orphan_inode(sbi); > +out: > + handle_failed_inode(inode); > + return err; > +} > + > +static int f2fs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) > +{ > + return __f2fs_tmpfile(dir, dentry, mode, NULL); > +} > + > +static int f2fs_create_whiteout(struct inode *dir, struct inode **whiteout) > +{ > + return __f2fs_tmpfile(dir, NULL, S_IFCHR | WHITEOUT_MODE, whiteout); > +} > + > static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry, > - struct inode *new_dir, struct dentry *new_dentry) > + struct inode *new_dir, struct dentry *new_dentry, > + unsigned int flags) > { > struct f2fs_sb_info *sbi = F2FS_I_SB(old_dir); > struct inode *old_inode = d_inode(old_dentry); > struct inode *new_inode = d_inode(new_dentry); > + struct inode *whiteout = NULL; > struct page *old_dir_page; > - struct page *old_page, *new_page; > + struct page *old_page, *new_page = NULL; > struct f2fs_dir_entry *old_dir_entry = NULL; > struct f2fs_dir_entry *old_entry; > struct f2fs_dir_entry *new_entry; > @@ -543,6 +609,12 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry, > goto out_old; > } > > + if (flags & RENAME_WHITEOUT) { > + err = f2fs_create_whiteout(old_dir, &whiteout); > + if (err) > + goto out_dir; > + } > + > if (new_inode) { > > err = -ENOTEMPTY; > @@ -611,8 +683,17 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry, > > f2fs_delete_entry(old_entry, old_page, old_dir, NULL); > > + if (whiteout) { > + whiteout->i_state |= I_LINKABLE; > + set_inode_flag(F2FS_I(whiteout), FI_INC_LINK); > + err = f2fs_add_link(old_dentry, whiteout); > + if (err) > + goto put_out_dir; > + whiteout->i_state &= ~I_LINKABLE; > + } > + > if (old_dir_entry) { > - if (old_dir != new_dir) { > + if (old_dir != new_dir && !whiteout) { > f2fs_set_link(old_inode, old_dir_entry, > old_dir_page, new_dir); > update_inode_page(old_inode); > @@ -633,8 +714,10 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry, > > put_out_dir: > f2fs_unlock_op(sbi); > - f2fs_dentry_kunmap(new_dir, new_page); > - f2fs_put_page(new_page, 0); > + if (new_page) { > + f2fs_dentry_kunmap(new_dir, new_page); > + f2fs_put_page(new_page, 0); > + } > out_dir: > if (old_dir_entry) { > f2fs_dentry_kunmap(old_inode, old_dir_page); > @@ -805,7 +888,7 @@ static int f2fs_rename2(struct inode *old_dir, struct dentry *old_dentry, > struct inode *new_dir, struct dentry *new_dentry, > unsigned int flags) > { > - if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) > + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT)) > return -EINVAL; > > if (flags & RENAME_EXCHANGE) { > @@ -816,50 +899,7 @@ static int f2fs_rename2(struct inode *old_dir, struct dentry *old_dentry, > * VFS has already handled the new dentry existence case, > * here, we just deal with "RENAME_NOREPLACE" as regular rename. > */ > - return f2fs_rename(old_dir, old_dentry, new_dir, new_dentry); > -} > - > -static int f2fs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) > -{ > - struct f2fs_sb_info *sbi = F2FS_I_SB(dir); > - struct inode *inode; > - int err; > - > - inode = f2fs_new_inode(dir, mode); > - if (IS_ERR(inode)) > - return PTR_ERR(inode); > - > - inode->i_op = &f2fs_file_inode_operations; > - inode->i_fop = &f2fs_file_operations; > - inode->i_mapping->a_ops = &f2fs_dblock_aops; > - > - f2fs_lock_op(sbi); > - err = acquire_orphan_inode(sbi); > - if (err) > - goto out; > - > - err = f2fs_do_tmpfile(inode, dir); > - if (err) > - goto release_out; > - > - /* > - * add this non-linked tmpfile to orphan list, in this way we could > - * remove all unused data of tmpfile after abnormal power-off. > - */ > - add_orphan_inode(sbi, inode->i_ino); > - f2fs_unlock_op(sbi); > - > - alloc_nid_done(sbi, inode->i_ino); > - > - d_tmpfile(dentry, inode); > - unlock_new_inode(inode); > - return 0; > - > -release_out: > - release_orphan_inode(sbi); > -out: > - handle_failed_inode(inode); > - return err; > + return f2fs_rename(old_dir, old_dentry, new_dir, new_dentry, flags); > } > > #ifdef CONFIG_F2FS_FS_ENCRYPTION > -- > 2.3.3 -- 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/