Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756968Ab1DGAwv (ORCPT ); Wed, 6 Apr 2011 20:52:51 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:43511 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755767Ab1DGAwu (ORCPT ); Wed, 6 Apr 2011 20:52:50 -0400 Message-ID: <4D9D0ADB.9010005@oracle.com> Date: Wed, 06 Apr 2011 17:52:43 -0700 From: Sunil Mushran User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.14) Gecko/20110223 Lightning/1.0b2 Thunderbird/3.1.8 MIME-Version: 1.0 To: djwong@us.ibm.com CC: "Theodore Ts'o" , Andreas Dilger , linux-ext4 , linux-kernel Subject: Re: [PATCH 1/2] ext4: Calculate and verify inode checksums References: <20110406224410.GB24354@tux1.beaverton.ibm.com> <20110406224547.GT32706@tux1.beaverton.ibm.com> In-Reply-To: <20110406224547.GT32706@tux1.beaverton.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: acsmt357.oracle.com [141.146.40.157] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090201.4D9D0ADD.00E7:SCFSTAT5015188,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5465 Lines: 145 On 04/06/2011 03:45 PM, Darrick J. Wong wrote: > This patch introduces to ext4 the ability to calculate and verify inode > checksums. This requires the use of a new ro compatibility flag and some > accompanying e2fsprogs patches to provide the relevant features in tune2fs and > e2fsck. > > Signed-off-by: Darrick J. Wong > --- > > fs/ext4/ext4.h | 6 ++++-- > fs/ext4/inode.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 55 insertions(+), 3 deletions(-) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 4daaf2b..8815928 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -617,7 +617,7 @@ struct ext4_inode { > } masix2; > } osd2; /* OS dependent 2 */ > __le16 i_extra_isize; > - __le16 i_pad1; > + __le16 i_checksum; /* crc16(sb_uuid+inodenum+inode) */ > __le32 i_ctime_extra; /* extra Change time (nsec<< 2 | epoch) */ > __le32 i_mtime_extra; /* extra Modification time(nsec<< 2 | epoch) */ > __le32 i_atime_extra; /* extra Access time (nsec<< 2 | epoch) */ > @@ -1338,6 +1338,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) > #define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0010 > #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK 0x0020 > #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE 0x0040 > +#define EXT4_FEATURE_RO_COMPAT_INODE_CSUM 0x0400 > > #define EXT4_FEATURE_INCOMPAT_COMPRESSION 0x0001 > #define EXT4_FEATURE_INCOMPAT_FILETYPE 0x0002 > @@ -1364,7 +1365,8 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) > EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \ > EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE | \ > EXT4_FEATURE_RO_COMPAT_BTREE_DIR |\ > - EXT4_FEATURE_RO_COMPAT_HUGE_FILE) > + EXT4_FEATURE_RO_COMPAT_HUGE_FILE |\ > + EXT4_FEATURE_RO_COMPAT_INODE_CSUM) > > /* > * Default values for user and/or group using reserved blocks > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 1a86282..dc76f19 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -42,6 +42,7 @@ > #include > #include > #include > +#include > > #include "ext4_jbd2.h" > #include "xattr.h" > @@ -52,6 +53,40 @@ > > #define MPAGE_DA_EXTENT_TAIL 0x01 > > +static __le16 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw) > +{ > + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > + struct ext4_inode_info *ei = EXT4_I(inode); > + int offset = offsetof(struct ext4_inode, i_checksum); > + __le32 inum = cpu_to_le32(inode->i_ino); > + __u16 crc = 0; > + > + if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, > + EXT4_FEATURE_RO_COMPAT_INODE_CSUM)&& > + le16_to_cpu(raw->i_extra_isize)>= 4) { > + crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid)); > + crc = crc16(crc, (__u8 *)&inum, sizeof(inum)); > + crc = crc16(crc, (__u8 *)raw, offset); > + offset += sizeof(raw->i_checksum); /* skip checksum */ > + /* for checksum of struct ext4_inode do the rest...*/ > + if (ei->i_extra_isize> 4) > + crc = crc16(crc, (__u8 *)raw + offset, > + ei->i_extra_isize - 4); > + } > + > + return cpu_to_le16(crc); > +} > + > +static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw) > +{ > + if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, > + EXT4_FEATURE_RO_COMPAT_INODE_CSUM)&& > + (raw->i_checksum != ext4_inode_csum(inode, raw))) > + return 0; > + > + return 1; > +} > + > static inline int ext4_begin_ordered_truncate(struct inode *inode, > loff_t new_size) > { > @@ -4802,7 +4837,8 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino) > struct ext4_inode *raw_inode; > struct ext4_inode_info *ei; > struct inode *inode; > - journal_t *journal = EXT4_SB(sb)->s_journal; > + struct ext4_sb_info *sbi = EXT4_SB(sb); > + journal_t *journal = sbi->s_journal; > long ret; > int block; > > @@ -4916,6 +4952,14 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino) > } else > ei->i_extra_isize = 0; > > + if (!ext4_inode_csum_verify(inode, raw_inode)) { > + EXT4_ERROR_INODE(inode, "checksum invalid (%u != %u)", > + le16_to_cpu(ext4_inode_csum(inode, raw_inode)), > + le16_to_cpu(raw_inode->i_checksum)); > + ret = -EIO; > + goto bad_inode; > + } > + > EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode); > EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode); > EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode); > @@ -5138,6 +5182,12 @@ static int ext4_do_update_inode(handle_t *handle, > raw_inode->i_version_hi = > cpu_to_le32(inode->i_version>> 32); > raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize); > + > + if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, > + EXT4_FEATURE_RO_COMPAT_INODE_CSUM)&& > + EXT4_FITS_IN_INODE(raw_inode, ei, i_checksum)) > + raw_inode->i_checksum = > + ext4_inode_csum(inode, raw_inode); > } > > BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); You may want to look into jbd2 buffer triggers. struct jbd2_buffer_trigger_type Instead of computing checksum on every update, it allows one to compute it just before the journal write. More efficient. -- 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/