ext4: Calculate and verify checksums for htree nodes
Calculate and verify the checksum for directory index tree (htree) node blocks. The checksum is stored in the last 4 bytes of the htree block and requires the dx_entry array to stop 1 dx_entry short of the end of the block. Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong
Theodore Ts'o
Родитель
7ac5990d5a
Коммит
dbe8944404
160
fs/ext4/namei.c
160
fs/ext4/namei.c
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@ -188,6 +188,121 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
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static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
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struct inode *inode);
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/* checksumming functions */
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static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
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struct ext4_dir_entry *dirent,
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int *offset)
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{
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struct ext4_dir_entry *dp;
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struct dx_root_info *root;
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int count_offset;
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if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
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count_offset = 8;
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else if (le16_to_cpu(dirent->rec_len) == 12) {
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dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
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if (le16_to_cpu(dp->rec_len) !=
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EXT4_BLOCK_SIZE(inode->i_sb) - 12)
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return NULL;
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root = (struct dx_root_info *)(((void *)dp + 12));
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if (root->reserved_zero ||
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root->info_length != sizeof(struct dx_root_info))
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return NULL;
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count_offset = 32;
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} else
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return NULL;
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if (offset)
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*offset = count_offset;
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return (struct dx_countlimit *)(((void *)dirent) + count_offset);
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}
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static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
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int count_offset, int count, struct dx_tail *t)
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{
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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struct ext4_inode_info *ei = EXT4_I(inode);
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__u32 csum, old_csum;
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int size;
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size = count_offset + (count * sizeof(struct dx_entry));
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old_csum = t->dt_checksum;
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t->dt_checksum = 0;
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csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
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csum = ext4_chksum(sbi, csum, (__u8 *)t, sizeof(struct dx_tail));
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t->dt_checksum = old_csum;
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return cpu_to_le32(csum);
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}
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static int ext4_dx_csum_verify(struct inode *inode,
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struct ext4_dir_entry *dirent)
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{
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struct dx_countlimit *c;
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struct dx_tail *t;
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int count_offset, limit, count;
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if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
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return 1;
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c = get_dx_countlimit(inode, dirent, &count_offset);
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if (!c) {
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EXT4_ERROR_INODE(inode, "dir seems corrupt? Run e2fsck -D.");
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return 1;
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}
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limit = le16_to_cpu(c->limit);
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count = le16_to_cpu(c->count);
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if (count_offset + (limit * sizeof(struct dx_entry)) >
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EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
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EXT4_ERROR_INODE(inode, "metadata_csum set but no space for "
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"tree checksum found. Run e2fsck -D.");
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return 1;
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}
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t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
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if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
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count, t))
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return 0;
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return 1;
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}
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static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
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{
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struct dx_countlimit *c;
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struct dx_tail *t;
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int count_offset, limit, count;
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if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
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return;
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c = get_dx_countlimit(inode, dirent, &count_offset);
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if (!c) {
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EXT4_ERROR_INODE(inode, "dir seems corrupt? Run e2fsck -D.");
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return;
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}
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limit = le16_to_cpu(c->limit);
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count = le16_to_cpu(c->count);
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if (count_offset + (limit * sizeof(struct dx_entry)) >
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EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
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EXT4_ERROR_INODE(inode, "metadata_csum set but no space for "
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"tree checksum. Run e2fsck -D.");
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return;
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}
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t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
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t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
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}
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static inline int ext4_handle_dirty_dx_node(handle_t *handle,
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struct inode *inode,
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struct buffer_head *bh)
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{
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ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
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return ext4_handle_dirty_metadata(handle, inode, bh);
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}
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/*
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* p is at least 6 bytes before the end of page
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*/
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@ -247,12 +362,20 @@ static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
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{
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unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
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EXT4_DIR_REC_LEN(2) - infosize;
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if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
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entry_space -= sizeof(struct dx_tail);
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return entry_space / sizeof(struct dx_entry);
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}
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static inline unsigned dx_node_limit(struct inode *dir)
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{
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unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
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if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
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entry_space -= sizeof(struct dx_tail);
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return entry_space / sizeof(struct dx_entry);
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}
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@ -398,6 +521,15 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
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goto fail;
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}
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if (!buffer_verified(bh) &&
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!ext4_dx_csum_verify(dir, (struct ext4_dir_entry *)bh->b_data)) {
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ext4_warning(dir->i_sb, "Root failed checksum");
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brelse(bh);
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*err = ERR_BAD_DX_DIR;
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goto fail;
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}
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set_buffer_verified(bh);
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entries = (struct dx_entry *) (((char *)&root->info) +
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root->info.info_length);
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@ -458,6 +590,17 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
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if (!(bh = ext4_bread (NULL,dir, dx_get_block(at), 0, err)))
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goto fail2;
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at = entries = ((struct dx_node *) bh->b_data)->entries;
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if (!buffer_verified(bh) &&
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!ext4_dx_csum_verify(dir,
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(struct ext4_dir_entry *)bh->b_data)) {
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ext4_warning(dir->i_sb, "Node failed checksum");
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brelse(bh);
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*err = ERR_BAD_DX_DIR;
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goto fail;
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}
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set_buffer_verified(bh);
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if (dx_get_limit(entries) != dx_node_limit (dir)) {
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ext4_warning(dir->i_sb,
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"dx entry: limit != node limit");
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@ -557,6 +700,15 @@ static int ext4_htree_next_block(struct inode *dir, __u32 hash,
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if (!(bh = ext4_bread(NULL, dir, dx_get_block(p->at),
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0, &err)))
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return err; /* Failure */
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if (!buffer_verified(bh) &&
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!ext4_dx_csum_verify(dir,
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(struct ext4_dir_entry *)bh->b_data)) {
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ext4_warning(dir->i_sb, "Node failed checksum");
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return -EIO;
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}
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set_buffer_verified(bh);
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p++;
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brelse(p->bh);
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p->bh = bh;
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@ -1232,7 +1384,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
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err = ext4_handle_dirty_metadata(handle, dir, bh2);
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if (err)
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goto journal_error;
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err = ext4_handle_dirty_metadata(handle, dir, frame->bh);
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err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
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if (err)
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goto journal_error;
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brelse(bh2);
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@ -1419,7 +1571,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
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frame->bh = bh;
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bh = bh2;
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ext4_handle_dirty_metadata(handle, dir, frame->bh);
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ext4_handle_dirty_dx_node(handle, dir, frame->bh);
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ext4_handle_dirty_metadata(handle, dir, bh);
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de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
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@ -1594,7 +1746,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
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dxtrace(dx_show_index("node", frames[1].entries));
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dxtrace(dx_show_index("node",
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((struct dx_node *) bh2->b_data)->entries));
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err = ext4_handle_dirty_metadata(handle, dir, bh2);
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err = ext4_handle_dirty_dx_node(handle, dir, bh2);
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if (err)
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goto journal_error;
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brelse (bh2);
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@ -1620,7 +1772,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
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if (err)
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goto journal_error;
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}
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err = ext4_handle_dirty_metadata(handle, dir, frames[0].bh);
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err = ext4_handle_dirty_dx_node(handle, dir, frames[0].bh);
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if (err) {
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ext4_std_error(inode->i_sb, err);
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goto cleanup;
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