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Date: Fri, 2 Sep 2011 11:57:44 -0700
From: "Darrick J. Wong" <djwong@...ibm.com>
To: Andreas Dilger <adilger.kernel@...ger.ca>
Cc: Theodore Tso <tytso@....edu>,
Sunil Mushran <sunil.mushran@...cle.com>,
Amir Goldstein <amir73il@...il.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
Andi Kleen <andi@...stfloor.org>,
Mingming Cao <cmm@...ibm.com>,
Joel Becker <jlbec@...lplan.org>,
linux-fsdevel <linux-fsdevel@...r.kernel.org>,
linux-ext4@...r.kernel.org, Coly Li <colyli@...il.com>
Subject: Re: [PATCH 12/16] ext4: Calculate and verify checksums of
directory leaf blocks
On Thu, Sep 01, 2011 at 01:36:50AM -0600, Andreas Dilger wrote:
> On 2011-08-31, at 6:31 PM, Darrick J. Wong wrote:
> > Calculate and verify the checksums for directory leaf blocks (i.e. blocks that
> > only contain actual directory entries). The checksum lives in what looks to be
> > an unused directory entry with a 0 name_len at the end of the block. This
> > scheme is not used for internal htree nodes because the mechanism in place
> > there only costs one dx_entry, whereas the "empty" directory entry would cost
> > two dx_entries.
> >
> > Signed-off-by: Darrick J. Wong <djwong@...ibm.com>
> > ---
> > fs/ext4/dir.c | 12 +++
> > fs/ext4/ext4.h | 13 +++
> > fs/ext4/namei.c | 259 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
> > 3 files changed, 269 insertions(+), 15 deletions(-)
> >
> >
> > diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
> > index 164c560..bc40c9e 100644
> > --- a/fs/ext4/dir.c
> > +++ b/fs/ext4/dir.c
> > @@ -180,6 +180,18 @@ static int ext4_readdir(struct file *filp,
> > continue;
> > }
> >
> > + /* Check the checksum */
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(inode,
> > + (struct ext4_dir_entry *)bh->b_data)) {
> > + EXT4_ERROR_FILE(filp, 0, "directory fails checksum "
> > + "at offset %llu",
> > + (unsigned long long)filp->f_pos);
> > + filp->f_pos += sb->s_blocksize - offset;
> > + continue;
> > + }
> > + set_buffer_verified(bh);
> > +
> > revalidate:
> > /* If the dir block has changed since the last call to
> > * readdir(2), then we might be pointing to an invalid
> > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> > index df149b3..b7aa5b5 100644
> > --- a/fs/ext4/ext4.h
> > +++ b/fs/ext4/ext4.h
> > @@ -1471,6 +1471,17 @@ struct ext4_dir_entry_2 {
> > };
> >
> > /*
> > + * This is a bogus directory entry at the end of each leaf block that
> > + * records checksums.
> > + */
> > +struct ext4_dir_entry_tail {
> > + __le32 reserved_zero1; /* Pretend to be unused */
> > + __le16 rec_len; /* 12 */
> > + __le16 reserved_zero2; /* Zero name length */
> > + __le32 checksum; /* crc32c(uuid+inum+dirblock) */
> > +};
>
> Since this field is stored inline with existing directory entries, it
> may make sense to also add a magic value to this entry (preferably one
> with non-ASCII values) so that it can be distinguished from an empty
> dirent that happens to be at the end of the block.
I could set the file type to 0xDE since currently there's only 8 file types
defined.
> > +/*
> > * Ext4 directory file types. Only the low 3 bits are used. The
> > * other bits are reserved for now.
> > */
> > @@ -1875,6 +1886,8 @@ extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);
> > extern int ext4_ext_migrate(struct inode *);
> >
> > /* namei.c */
> > +extern int ext4_dirent_csum_verify(struct inode *inode,
> > + struct ext4_dir_entry *dirent);
> > extern int ext4_orphan_add(handle_t *, struct inode *);
> > extern int ext4_orphan_del(handle_t *, struct inode *);
> > extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
> > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> > index 89797bf..2d0fdb9 100644
> > --- a/fs/ext4/namei.c
> > +++ b/fs/ext4/namei.c
> > @@ -191,6 +191,104 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
> > struct inode *inode);
> >
> > /* checksumming functions */
> > +static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
> > + struct ext4_dir_entry *de)
> > +{
> > + struct ext4_dir_entry *d, *top;
> > + struct ext4_dir_entry_tail *t;
> > +
> > + d = de;
> > + top = (struct ext4_dir_entry *)(((void *)de) +
> > + (EXT4_BLOCK_SIZE(inode->i_sb) -
> > + sizeof(struct ext4_dir_entry_tail)));
> > + while (d < top && d->rec_len)
> > + d = (struct ext4_dir_entry *)(((void *)d) +
> > + le16_to_cpu(d->rec_len));
>
> Calling get_dirent_tail() is fairly expensive, because it has to walk
> the whole directory block each time. When filling a block it would
> be O(n^2) for the number of entries in the block.
>
> It would be more efficient to just cast the end of the directory block
> to the ext4_dir_entry_tail and check its validity, which is especially
> easy if there is a magic value in it.
>
> > + if (d != top)
> > + return NULL;
> > +
> > + t = (struct ext4_dir_entry_tail *)d;
> > + if (t->reserved_zero1 ||
> > + le16_to_cpu(t->rec_len) != sizeof(struct ext4_dir_entry_tail) ||
> > + t->reserved_zero2)
>
> I'd prefer these reserved_zero[12] fields be explicitly compared to zero
> instead of treated as boolean values.
Ok.
> > + return NULL;
> > +
> > + return t;
> > +}
> > +
> > +static __le32 ext4_dirent_csum(struct inode *inode,
> > + struct ext4_dir_entry *dirent)
> > +{
> > + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> > + struct ext4_dir_entry_tail *t;
> > + __le32 inum = cpu_to_le32(inode->i_ino);
> > + int size;
> > + __u32 crc = 0;
> > +
> > + if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + return 0;
> > +
> > + t = get_dirent_tail(inode, dirent);
>
> > + if (!t)
> > + return 0;
> > +
> > + size = (void *)t - (void *)dirent;
> > + crc = crc32c_le(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
> > + crc = crc32c_le(crc, (__u8 *)&inum, sizeof(inum));
>
> Based on the number of times that the s_uuid+inum checksum is used in this
> code, and since it is constant for the life of the inode, it probably
> makes sense to precompute it and store it in ext4_inode_info.
Agreed.
> Also, now that I think about it, these checksums that contain the inum
> should also contain i_generation, so that there is no confusion with
> accessing old blocks on disk.
i_generation only gets updated when inodes are created or SETVERSION ioctl is
called, correct? I guess it wouldn't be too difficult to rewrite all file
metadata, though it could get a little expensive.
> > + crc = crc32c_le(crc, (__u8 *)dirent, size);
> > + return cpu_to_le32(crc);
> > +}
> > +
> > +int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
> > +{
> > + struct ext4_dir_entry_tail *t;
> > +
> > + if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + return 1;
> > +
> > + t = get_dirent_tail(inode, dirent);
> > + if (!t) {
> > + EXT4_ERROR_INODE(inode, "metadata_csum set but no space in dir "
> > + "leaf for checksum. Please run e2fsck -D.");
> > + return 0;
> > + }
>
> I don't think this should necessarily be considered an error. That
> there is no space in the directory block is not a sign of corruption.
I was trying to steer users towards running fsck, which will notice the lack of
space and rebuild the dir. With a somewhat large mallet. :)
> > +
> > + if (t->checksum != ext4_dirent_csum(inode, dirent))
> > + return 0;
> > +
> > + return 1;
> > +}
> > +
> > +static void ext4_dirent_csum_set(struct inode *inode,
> > + struct ext4_dir_entry *dirent)
> > +{
> > + struct ext4_dir_entry_tail *t;
> > +
> > + if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + return;
> > +
> > + t = get_dirent_tail(inode, dirent);
> > + if (!t) {
> > + EXT4_ERROR_INODE(inode, "metadata_csum set but no space in dir "
> > + "leaf for checksum. Please run e2fsck -D.");
> > + return;
> > + }
> > +
> > + t->checksum = ext4_dirent_csum(inode, dirent);
> > +}
> > +
> > +static inline int ext4_handle_dirty_dirent_node(handle_t *handle,
> > + struct inode *inode,
> > + struct buffer_head *bh)
> > +{
> > + ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
> > + return ext4_handle_dirty_metadata(handle, inode, bh);
> > +}
> > +
> > static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
> > struct ext4_dir_entry *dirent,
> > int *offset)
> > @@ -748,6 +846,11 @@ static int htree_dirblock_to_tree(struct file *dir_file,
> > if (!(bh = ext4_bread (NULL, dir, block, 0, &err)))
> > return err;
> >
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(dir, (struct ext4_dir_entry *)bh->b_data))
> > + return -EIO;
> > + set_buffer_verified(bh);
> > +
> > de = (struct ext4_dir_entry_2 *) bh->b_data;
>
> You might as well set de before calling ext4_dirent_csum_verify() to avoid
> having another unsightly cast.
Ok.
> > top = (struct ext4_dir_entry_2 *) ((char *) de +
> > dir->i_sb->s_blocksize -
> > @@ -1106,6 +1209,15 @@ restart:
> > brelse(bh);
> > goto next;
> > }
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(dir,
> > + (struct ext4_dir_entry *)bh->b_data)) {
> > + EXT4_ERROR_INODE(dir, "checksumming directory "
> > + "block %lu", (unsigned long)block);
> > + brelse(bh);
> > + goto next;
> > + }
> > + set_buffer_verified(bh);
> > i = search_dirblock(bh, dir, d_name,
> > block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
> > if (i == 1) {
> > @@ -1157,6 +1269,16 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct q
> > if (!(bh = ext4_bread(NULL, dir, block, 0, err)))
> > goto errout;
> >
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(dir,
> > + (struct ext4_dir_entry *)bh->b_data)) {
> > + EXT4_ERROR_INODE(dir, "checksumming directory "
> > + "block %lu", (unsigned long)block);
> > + brelse(bh);
> > + *err = -EIO;
> > + goto errout;
> > + }
> > + set_buffer_verified(bh);
> > retval = search_dirblock(bh, dir, d_name,
> > block << EXT4_BLOCK_SIZE_BITS(sb),
> > res_dir);
> > @@ -1329,8 +1451,14 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
> > char *data1 = (*bh)->b_data, *data2;
> > unsigned split, move, size;
> > struct ext4_dir_entry_2 *de = NULL, *de2;
> > + struct ext4_dir_entry_tail *t;
> > + int csum_size = 0;
> > int err = 0, i;
> >
> > + if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + csum_size = sizeof(struct ext4_dir_entry_tail);
> > +
> > bh2 = ext4_append (handle, dir, &newblock, &err);
> > if (!(bh2)) {
> > brelse(*bh);
> > @@ -1377,10 +1505,24 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
> > /* Fancy dance to stay within two buffers */
> > de2 = dx_move_dirents(data1, data2, map + split, count - split, blocksize);
> > de = dx_pack_dirents(data1, blocksize);
> > - de->rec_len = ext4_rec_len_to_disk(data1 + blocksize - (char *) de,
> > + de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
> > + (char *) de,
> > blocksize);
>
> (style) This should be "(char *)de, blocksize);"
>
> > - de2->rec_len = ext4_rec_len_to_disk(data2 + blocksize - (char *) de2,
> > + de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
> > + (char *) de2,
> > blocksize);
>
> (style) likewise
>
> > + if (csum_size) {
> > + t = (struct ext4_dir_entry_tail *)(data2 +
> > + (blocksize - csum_size));
> > + memset(t, 0, csum_size);
> > + t->rec_len = ext4_rec_len_to_disk(csum_size, blocksize);
> > +
> > + t = (struct ext4_dir_entry_tail *)(data1 +
> > + (blocksize - csum_size));
> > + memset(t, 0, csum_size);
> > + t->rec_len = ext4_rec_len_to_disk(csum_size, blocksize);
> > + }
> > +
> > dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
> > dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
> >
> > @@ -1391,7 +1533,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
> > de = de2;
> > }
> > dx_insert_block(frame, hash2 + continued, newblock);
> > - err = ext4_handle_dirty_metadata(handle, dir, bh2);
> > + err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
> > if (err)
> > goto journal_error;
> > err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
> > @@ -1431,11 +1573,16 @@ static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
> > unsigned short reclen;
> > int nlen, rlen, err;
> > char *top;
> > + int csum_size = 0;
> > +
> > + if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + csum_size = sizeof(struct ext4_dir_entry_tail);
> >
> > reclen = EXT4_DIR_REC_LEN(namelen);
> > if (!de) {
> > de = (struct ext4_dir_entry_2 *)bh->b_data;
> > - top = bh->b_data + blocksize - reclen;
> > + top = bh->b_data + (blocksize - csum_size) - reclen;
> > while ((char *) de <= top) {
> > if (ext4_check_dir_entry(dir, NULL, de, bh, offset))
> > return -EIO;
> > @@ -1491,7 +1638,7 @@ static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
> > dir->i_version++;
> > ext4_mark_inode_dirty(handle, dir);
> > BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
> > - err = ext4_handle_dirty_metadata(handle, dir, bh);
> > + err = ext4_handle_dirty_dirent_node(handle, dir, bh);
> > if (err)
> > ext4_std_error(dir->i_sb, err);
> > return 0;
> > @@ -1512,6 +1659,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
> > struct dx_frame frames[2], *frame;
> > struct dx_entry *entries;
> > struct ext4_dir_entry_2 *de, *de2;
> > + struct ext4_dir_entry_tail *t;
> > char *data1, *top;
> > unsigned len;
> > int retval;
> > @@ -1519,6 +1667,11 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
> > struct dx_hash_info hinfo;
> > ext4_lblk_t block;
> > struct fake_dirent *fde;
> > + int csum_size = 0;
> > +
> > + if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + csum_size = sizeof(struct ext4_dir_entry_tail);
> >
> > blocksize = dir->i_sb->s_blocksize;
> > dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
> > @@ -1539,7 +1692,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
> > brelse(bh);
> > return -EIO;
> > }
> > - len = ((char *) root) + blocksize - (char *) de;
> > + len = ((char *) root) + (blocksize - csum_size) - (char *) de;
>
> (style) "(char *)root)" and "(char *)de".
>
> > /* Allocate new block for the 0th block's dirents */
> > bh2 = ext4_append(handle, dir, &block, &retval);
> > @@ -1555,8 +1708,17 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
> > top = data1 + len;
> > while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
> > de = de2;
> > - de->rec_len = ext4_rec_len_to_disk(data1 + blocksize - (char *) de,
> > + de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
> > + (char *) de,
> > blocksize);
>
> Likewise.
Ok, I'll fix the style complaints. Should checkpatch find these things?
--D
> > +
> > + if (csum_size) {
> > + t = (struct ext4_dir_entry_tail *)(data1 +
> > + (blocksize - csum_size));
> > + memset(t, 0, csum_size);
> > + t->rec_len = ext4_rec_len_to_disk(csum_size, blocksize);
> > + }
> > +
> > /* Initialize the root; the dot dirents already exist */
> > de = (struct ext4_dir_entry_2 *) (&root->dotdot);
> > de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
> > @@ -1582,7 +1744,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
> > bh = bh2;
> >
> > ext4_handle_dirty_dx_node(handle, dir, frame->bh);
> > - ext4_handle_dirty_metadata(handle, dir, bh);
> > + ext4_handle_dirty_dirent_node(handle, dir, bh);
> >
> > de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
> > if (!de) {
> > @@ -1618,11 +1780,17 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
> > struct inode *dir = dentry->d_parent->d_inode;
> > struct buffer_head *bh;
> > struct ext4_dir_entry_2 *de;
> > + struct ext4_dir_entry_tail *t;
> > struct super_block *sb;
> > int retval;
> > int dx_fallback=0;
> > unsigned blocksize;
> > ext4_lblk_t block, blocks;
> > + int csum_size = 0;
> > +
> > + if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + csum_size = sizeof(struct ext4_dir_entry_tail);
> >
> > sb = dir->i_sb;
> > blocksize = sb->s_blocksize;
> > @@ -1641,6 +1809,11 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
> > bh = ext4_bread(handle, dir, block, 0, &retval);
> > if(!bh)
> > return retval;
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(dir,
> > + (struct ext4_dir_entry *)bh->b_data))
> > + return -EIO;
> > + set_buffer_verified(bh);
> > retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
> > if (retval != -ENOSPC) {
> > brelse(bh);
> > @@ -1657,7 +1830,15 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
> > return retval;
> > de = (struct ext4_dir_entry_2 *) bh->b_data;
> > de->inode = 0;
> > - de->rec_len = ext4_rec_len_to_disk(blocksize, blocksize);
> > + de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
> > +
> > + if (csum_size) {
> > + t = (struct ext4_dir_entry_tail *)(((void *)bh->b_data) +
> > + (blocksize - csum_size));
> > + memset(t, 0, csum_size);
> > + t->rec_len = ext4_rec_len_to_disk(csum_size, blocksize);
> > + }
> > +
> > retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
> > brelse(bh);
> > if (retval == 0)
> > @@ -1689,6 +1870,11 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
> > if (!(bh = ext4_bread(handle,dir, dx_get_block(frame->at), 0, &err)))
> > goto cleanup;
> >
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(dir, (struct ext4_dir_entry *)bh->b_data))
> > + goto journal_error;
> > + set_buffer_verified(bh);
> > +
> > BUFFER_TRACE(bh, "get_write_access");
> > err = ext4_journal_get_write_access(handle, bh);
> > if (err)
> > @@ -1814,12 +2000,17 @@ static int ext4_delete_entry(handle_t *handle,
> > {
> > struct ext4_dir_entry_2 *de, *pde;
> > unsigned int blocksize = dir->i_sb->s_blocksize;
> > + int csum_size = 0;
> > int i, err;
> >
> > + if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + csum_size = sizeof(struct ext4_dir_entry_tail);
> > +
> > i = 0;
> > pde = NULL;
> > de = (struct ext4_dir_entry_2 *) bh->b_data;
> > - while (i < bh->b_size) {
> > + while (i < bh->b_size - csum_size) {
> > if (ext4_check_dir_entry(dir, NULL, de, bh, i))
> > return -EIO;
> > if (de == de_del) {
> > @@ -1840,7 +2031,7 @@ static int ext4_delete_entry(handle_t *handle,
> > de->inode = 0;
> > dir->i_version++;
> > BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
> > - err = ext4_handle_dirty_metadata(handle, dir, bh);
> > + err = ext4_handle_dirty_dirent_node(handle, dir, bh);
> > if (unlikely(err)) {
> > ext4_std_error(dir->i_sb, err);
> > return err;
> > @@ -1983,9 +2174,15 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, int mode)
> > struct inode *inode;
> > struct buffer_head *dir_block = NULL;
> > struct ext4_dir_entry_2 *de;
> > + struct ext4_dir_entry_tail *t;
> > unsigned int blocksize = dir->i_sb->s_blocksize;
> > + int csum_size = 0;
> > int err, retries = 0;
> >
> > + if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
> > + csum_size = sizeof(struct ext4_dir_entry_tail);
> > +
> > if (EXT4_DIR_LINK_MAX(dir))
> > return -EMLINK;
> >
> > @@ -2026,16 +2223,26 @@ retry:
> > ext4_set_de_type(dir->i_sb, de, S_IFDIR);
> > de = ext4_next_entry(de, blocksize);
> > de->inode = cpu_to_le32(dir->i_ino);
> > - de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(1),
> > + de->rec_len = ext4_rec_len_to_disk(blocksize -
> > + (csum_size + EXT4_DIR_REC_LEN(1)),
> > blocksize);
> > de->name_len = 2;
> > strcpy(de->name, "..");
> > ext4_set_de_type(dir->i_sb, de, S_IFDIR);
> > inode->i_nlink = 2;
> > +
> > + if (csum_size) {
> > + t = (struct ext4_dir_entry_tail *)(((void *)dir_block->b_data) +
> > + (blocksize - csum_size));
> > + memset(t, 0, csum_size);
> > + t->rec_len = ext4_rec_len_to_disk(csum_size, blocksize);
> > + }
> > +
> > BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
> > - err = ext4_handle_dirty_metadata(handle, inode, dir_block);
> > + err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
> > if (err)
> > goto out_clear_inode;
> > + set_buffer_verified(dir_block);
> > err = ext4_mark_inode_dirty(handle, inode);
> > if (!err)
> > err = ext4_add_entry(handle, dentry, inode);
> > @@ -2085,6 +2292,14 @@ static int empty_dir(struct inode *inode)
> > inode->i_ino);
> > return 1;
> > }
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(inode,
> > + (struct ext4_dir_entry *)bh->b_data)) {
> > + EXT4_ERROR_INODE(inode, "checksum error reading directory "
> > + "lblock 0");
> > + return -EIO;
> > + }
> > + set_buffer_verified(bh);
> > de = (struct ext4_dir_entry_2 *) bh->b_data;
> > de1 = ext4_next_entry(de, sb->s_blocksize);
> > if (le32_to_cpu(de->inode) != inode->i_ino ||
> > @@ -2116,6 +2331,14 @@ static int empty_dir(struct inode *inode)
> > offset += sb->s_blocksize;
> > continue;
> > }
> > + if (!buffer_verified(bh) &&
> > + !ext4_dirent_csum_verify(inode,
> > + (struct ext4_dir_entry *)bh->b_data)) {
> > + EXT4_ERROR_INODE(inode, "checksum error "
> > + "reading directory lblock 0");
> > + return -EIO;
> > + }
> > + set_buffer_verified(bh);
> > de = (struct ext4_dir_entry_2 *) bh->b_data;
> > }
> > if (ext4_check_dir_entry(inode, NULL, de, bh, offset)) {
> > @@ -2616,6 +2839,11 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
> > dir_bh = ext4_bread(handle, old_inode, 0, 0, &retval);
> > if (!dir_bh)
> > goto end_rename;
> > + if (!buffer_verified(dir_bh) &&
> > + !ext4_dirent_csum_verify(old_inode,
> > + (struct ext4_dir_entry *)dir_bh->b_data))
> > + goto end_rename;
> > + set_buffer_verified(dir_bh);
> > if (le32_to_cpu(PARENT_INO(dir_bh->b_data,
> > old_dir->i_sb->s_blocksize)) != old_dir->i_ino)
> > goto end_rename;
> > @@ -2646,7 +2874,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
> > ext4_current_time(new_dir);
> > ext4_mark_inode_dirty(handle, new_dir);
> > BUFFER_TRACE(new_bh, "call ext4_handle_dirty_metadata");
> > - retval = ext4_handle_dirty_metadata(handle, new_dir, new_bh);
> > + retval = ext4_handle_dirty_dirent_node(handle, new_dir, new_bh);
> > if (unlikely(retval)) {
> > ext4_std_error(new_dir->i_sb, retval);
> > goto end_rename;
> > @@ -2700,7 +2928,8 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
> > PARENT_INO(dir_bh->b_data, new_dir->i_sb->s_blocksize) =
> > cpu_to_le32(new_dir->i_ino);
> > BUFFER_TRACE(dir_bh, "call ext4_handle_dirty_metadata");
> > - retval = ext4_handle_dirty_metadata(handle, old_inode, dir_bh);
> > + retval = ext4_handle_dirty_dirent_node(handle, old_inode,
> > + dir_bh);
> > if (retval) {
> > ext4_std_error(old_dir->i_sb, retval);
> > goto end_rename;
> >
>
--
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