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Date: Mon, 5 Sep 2011 11:59:46 -0700
From: "Darrick J. Wong" <djwong@...ibm.com>
To: Andreas Dilger <aedilger@...il.com>
Cc: Andreas Dilger <adilger.kernel@...ger.ca>,
Theodore Tso <tytso@....edu>,
Sunil Mushran <sunil.mushran@...cle.com>,
Amir Goldstein <amir73il@...il.com>,
Andi Kleen <andi@...stfloor.org>,
Mingming Cao <cmm@...ibm.com>,
Joel Becker <jlbec@...lplan.org>,
"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
Coly Li <colyli@...il.com>
Subject: Re: [PATCH 06/37] libext2fs: Add inode checksum support
On Sun, Sep 04, 2011 at 11:59:44AM -0600, Andreas Dilger wrote:
> On 2011-08-31, at 6:35 PM, "Darrick J. Wong" <djwong@...ibm.com> wrote:
>
> > This patch adds the ability for the libext2fs functions to read and write the
> > inode checksum. It also fixes a few fields that were omitted from the byte
> > swapping routines.
> >
> > Signed-off-by: Darrick J. Wong <djwong@...ibm.com>
> > ---
> > lib/ext2fs/csum.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
> > lib/ext2fs/ext2_err.et.in | 9 +++++++
> > lib/ext2fs/ext2_fs.h | 4 ++-
> > lib/ext2fs/ext2fs.h | 6 +++++
> > lib/ext2fs/inode.c | 20 +++++++++++++++
> > lib/ext2fs/swapfs.c | 10 ++++++--
> > 6 files changed, 104 insertions(+), 4 deletions(-)
> >
> >
> > diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
> > index 2fece68..57adc4c 100644
> > --- a/lib/ext2fs/csum.c
> > +++ b/lib/ext2fs/csum.c
> > @@ -29,6 +29,65 @@
> > #define STATIC static
> > #endif
> >
> > +__u32 ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
> > + struct ext2_inode_large *inode)
> > +{
> > + struct ext2_inode_large *desc = inode;
> > + int offset = offsetof(struct ext2_inode_large, i_checksum);
> > + int extra_size = inode->i_extra_isize;
> > + size_t size = fs->super->s_inode_size;
> > + __u32 crc = 0;
> > +
> > + if (size < EXT2_GOOD_OLD_INODE_SIZE + extra_size)
> > + printf("ERROR: inode %d size %d != extra_size %d!\n", inum,
> > + size, extra_size + EXT2_GOOD_OLD_INODE_SIZE);
>
> This shouldn't have to be checked for every inode checksum. If the checksum
> is covering the whole inode size then this is a constant size, and e2fsck is
> already checking the value of i_extra_isize.
This actually comes out later in the patchset when I change the checksum to
cover the entire inode size. I'll remove this hunk since it goes away.
--D
>
> > + if (fs->super->s_creator_os != EXT2_OS_LINUX)
> > + return 0;
> > +
> > + if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > +
> > + return 0;
> > +
> > +#ifdef WORDS_BIGENDIAN
> > + char buf[EXT2_INODE_CORE_SIZE(fs->super)];
> > + struct ext2_inode_large *swabinode = (struct ext2_inode_large *)buf;
> > +
> > + /* Have to swab back to little-endian to do the checksum */
> > + memcpy(swabinode, inode, size);
> > + ext2fs_swap_inode_full(fs, swabinode, swabinode, 1, size);
> > + desc = swabinode;
> > +#endif
> > + inum = ext2fs_cpu_to_le32(inum);
> > + crc = crc32c_le(~0, fs->super->s_uuid, sizeof(fs->super->s_uuid));
> > + crc = crc32c_le(crc, (char *)&inum, sizeof(inum));
> > + crc = crc32c_le(crc, (char *)desc, offset);
> > + offset += sizeof(inode->i_checksum); /* skip checksum */
> > + crc = crc32c_le(crc, (char *)desc + offset,
> > + EXT2_GOOD_OLD_INODE_SIZE + extra_size - offset);
> > + return crc;
> > +}
> > +
> > +int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
> > + struct ext2_inode_large *inode)
> > +{
> > + if (fs->super->s_creator_os == EXT2_OS_LINUX &&
> > + EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
> > + (inode->i_checksum != ext2fs_inode_csum(fs, inum, inode)))
> > + return 0;
> > + return 1;
> > +}
> > +
> > +void ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
> > + struct ext2_inode_large *inode)
> > +{
> > + if (fs->super->s_creator_os != EXT2_OS_LINUX)
> > + return;
> > + inode->i_checksum = ext2fs_inode_csum(fs, inum, inode);
> > +}
> > +
> > STATIC __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
> > {
> > __u16 crc = 0;
> > diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
> > index 995ddc3..31c8fe1 100644
> > --- a/lib/ext2fs/ext2_err.et.in
> > +++ b/lib/ext2fs/ext2_err.et.in
> > @@ -422,4 +422,13 @@ ec EXT2_NO_MTAB_FILE,
> > ec EXT2_ET_CANT_USE_LEGACY_BITMAPS,
> > "Filesystem too large to use legacy bitmaps"
> >
> > +ec EXT2_ET_INODE_CSUM_INVALID,
> > + "Inode checksum is incorrect"
> > +
> > +ec EXT2_ET_INODE_CORRUPT,
> > + "Inode checksum indicates corruption"
> > +
> > +ec EXT2_ET_INODE_CSUM_NONZERO,
> > + "Inode checksum should not be set"
> > +
> > end
> > diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
> > index ae7662e..1f08673 100644
> > --- a/lib/ext2fs/ext2_fs.h
> > +++ b/lib/ext2fs/ext2_fs.h
> > @@ -362,7 +362,7 @@ struct ext2_inode_large {
> > __u16 l_i_file_acl_high;
> > __u16 l_i_uid_high; /* these 2 fields */
> > __u16 l_i_gid_high; /* were reserved2[0] */
> > - __u32 l_i_reserved2;
> > + __u32 l_i_checksum; /* crc32c(uuid+inum+inode) */
> > } linux2;
> > struct {
> > __u8 h_i_frag; /* Fragment number */
> > @@ -393,7 +393,7 @@ struct ext2_inode_large {
> > #define i_gid_low i_gid
> > #define i_uid_high osd2.linux2.l_i_uid_high
> > #define i_gid_high osd2.linux2.l_i_gid_high
> > -#define i_reserved2 osd2.linux2.l_i_reserved2
> > +#define i_checksum osd2.linux2.l_i_checksum
> > #else
> > #if defined(__GNU__)
> >
> > diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> > index e571508..db8b28b 100644
> > --- a/lib/ext2fs/ext2fs.h
> > +++ b/lib/ext2fs/ext2fs.h
> > @@ -892,6 +892,12 @@ extern __u32 crc32c_be(__u32 crc, unsigned char const *p, size_t len);
> > extern __u32 crc32c_le(__u32 crc, unsigned char const *p, size_t len);
> >
> > /* csum.c */
> > +extern __u32 ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
> > + struct ext2_inode_large *inode);
> > +extern void ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
> > + struct ext2_inode_large *inode);
> > +extern int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
> > + struct ext2_inode_large *inode);
> > extern void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group);
> > extern int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group);
> > extern errcode_t ext2fs_set_gdt_csum(ext2_filsys fs);
> > diff --git a/lib/ext2fs/inode.c b/lib/ext2fs/inode.c
> > index 76893fd..0789505 100644
> > --- a/lib/ext2fs/inode.c
> > +++ b/lib/ext2fs/inode.c
> > @@ -509,6 +509,12 @@ errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
> > if (EXT2_INODE_SIZE(scan->fs->super) == EXT2_GOOD_OLD_INODE_SIZE)
> > inode->i_extra_isize = 0;
> >
> > + /* Verify the inode checksum. */
> > + if (!(scan->fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
> > + !ext2fs_inode_csum_verify(scan->fs, scan->current_inode, inode))
> > + return EXT2_ET_INODE_CSUM_INVALID;
> > +
> > +
> > scan->inodes_left--;
> > scan->current_inode++;
> > *ino = scan->current_inode;
> > @@ -617,6 +623,10 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
> > (struct ext2_inode_large *) inode,
> > 0, bufsize);
> > #endif
> > + /* Verify the inode checksum. */
> > + if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
> > + !ext2fs_inode_csum_verify(fs, ino, inode))
> > + return EXT2_ET_INODE_CSUM_INVALID;
> >
> > /* Update the inode cache */
> > fs->icache->cache_last = (fs->icache->cache_last + 1) %
> > @@ -685,6 +695,16 @@ errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
> > w_inode = &temp_inode;
> > memset(w_inode, 0, length);
> >
> > + /*
> > + * If inode checksum enabled, ensure that we actually have the whole
> > + * inode in memory.
> > + */
> > + if (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
> > + bufsize <= EXT2_GOOD_OLD_INODE_SIZE) {
> > + fprintf(stderr, "inode %d has a too-short buffer!\n", ino);
> > + abort();
> > + }
> > + ext2fs_inode_csum_set(fs, ino, inode);
> > #ifdef WORDS_BIGENDIAN
> > ext2fs_swap_inode_full(fs, w_inode, inode, 1, bufsize);
> > #else
> > diff --git a/lib/ext2fs/swapfs.c b/lib/ext2fs/swapfs.c
> > index 517f1d7..df604ba 100644
> > --- a/lib/ext2fs/swapfs.c
> > +++ b/lib/ext2fs/swapfs.c
> > @@ -244,8 +244,7 @@ void ext2fs_swap_inode_full(ext2_filsys fs, struct ext2_inode_large *t,
> > ext2fs_swab16 (f->osd2.linux2.l_i_uid_high);
> > t->osd2.linux2.l_i_gid_high =
> > ext2fs_swab16 (f->osd2.linux2.l_i_gid_high);
> > - t->osd2.linux2.l_i_reserved2 =
> > - ext2fs_swab32(f->osd2.linux2.l_i_reserved2);
> > + t->i_checksum = ext2fs_swab32(f->i_checksum);
> > break;
> > case EXT2_OS_HURD:
> > t->osd1.hurd1.h_i_translator =
> > @@ -279,6 +278,13 @@ void ext2fs_swap_inode_full(ext2_filsys fs, struct ext2_inode_large *t,
> > return;
> > }
> >
> > + t->i_ctime_extra = ext2fs_swab32(f->i_ctime_extra);
> > + t->i_mtime_extra = ext2fs_swab32(f->i_mtime_extra);
> > + t->i_atime_extra = ext2fs_swab32(f->i_atime_extra);
> > + t->i_crtime = ext2fs_swab32(f->i_crtime);
> > + t->i_crtime_extra = ext2fs_swab32(f->i_crtime_extra);
> > + t->i_version_hi = ext2fs_swab32(f->i_version_hi);
> > +
> > i = EXT2_GOOD_OLD_INODE_SIZE + extra_isize + sizeof(__u32);
> > if (bufsize < (int) i)
> > return; /* no space for EA magic */
> >
> > --
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