From: Andreas Dilger Subject: Re: [PATCH v2] ext4: check inline directory before converting Date: Fri, 25 Jul 2014 23:57:03 -0600 Message-ID: <1A1C51F5-7756-48FA-ABE0-F7D7B7F4AE0B@dilger.ca> References: <20140725222356.GK8628@birch.djwong.org> Mime-Version: 1.0 (1.0) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: Theodore Ts'o , Zheng Liu , linux-ext4 To: "Darrick J. Wong" Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:58377 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750717AbaGZF5H convert rfc822-to-8bit (ORCPT ); Sat, 26 Jul 2014 01:57:07 -0400 Received: by mail-pa0-f54.google.com with SMTP id fa1so7131357pad.41 for ; Fri, 25 Jul 2014 22:57:06 -0700 (PDT) In-Reply-To: <20140725222356.GK8628@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: Thanks. I'll see if i can share this with the directory checking code in dir.c, but for now you can add my: Signed-off-by: Andreas Dilger Cheers, Andreas > On Jul 25, 2014, at 16:23, "Darrick J. Wong" wrote: > > Before converting an inline directory to a regular directory, check > the directory entries to make sure they're not obviously broken. > This helps us to avoid a BUG_ON if one of the dirents is trashed. > > Signed-off-by: Darrick J. Wong > --- > fs/ext4/dir.c | 25 +++++++++++++++++++++++++ > fs/ext4/ext4.h | 2 ++ > fs/ext4/inline.c | 12 ++++++++++++ > 3 files changed, 39 insertions(+) > > diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c > index ef1bed6..0bb3f9e 100644 > --- a/fs/ext4/dir.c > +++ b/fs/ext4/dir.c > @@ -571,6 +571,31 @@ static int ext4_release_dir(struct inode *inode, struct file *filp) > return 0; > } > > +int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf, > + int buf_size) > +{ > + struct ext4_dir_entry_2 *de; > + int nlen, rlen; > + unsigned int offset = 0; > + char *top; > + > + de = (struct ext4_dir_entry_2 *)buf; > + top = buf + buf_size; > + while ((char *) de < top) { > + if (ext4_check_dir_entry(dir, NULL, de, bh, > + buf, buf_size, offset)) > + return -EIO; > + nlen = EXT4_DIR_REC_LEN(de->name_len); > + rlen = ext4_rec_len_from_disk(de->rec_len, buf_size); > + de = (struct ext4_dir_entry_2 *)((char *)de + rlen); > + offset += rlen; > + } > + if ((char *) de > top) > + return -EIO; > + > + return 0; > +} > + > const struct file_operations ext4_dir_operations = { > .llseek = ext4_dir_llseek, > .read = generic_read_dir, > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 22b790e..4726d5f 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -2064,6 +2064,8 @@ static inline unsigned char get_dtype(struct super_block *sb, int filetype) > > return ext4_filetype_table[filetype]; > } > +extern int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, > + void *buf, int buf_size); > > /* fsync.c */ > extern int ext4_sync_file(struct file *, loff_t, loff_t, int); > diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c > index 645205d..fc54169 100644 > --- a/fs/ext4/inline.c > +++ b/fs/ext4/inline.c > @@ -1178,6 +1178,18 @@ static int ext4_convert_inline_data_nolock(handle_t *handle, > if (error < 0) > goto out; > > + /* > + * Make sure the inline directory entries pass checks before we try to > + * convert them, so that we avoid touching stuff that needs fsck. > + */ > + if (S_ISDIR(inode->i_mode)) { > + error = ext4_check_all_de(inode, iloc->bh, > + buf + EXT4_INLINE_DOTDOT_SIZE, > + inline_size - EXT4_INLINE_DOTDOT_SIZE); > + if (error) > + goto out; > + } > + > error = ext4_destroy_inline_data_nolock(handle, inode); > if (error) > goto out;