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| author | Darrick J. Wong <djwong@us.ibm.com> | 2012-04-29 18:41:10 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2012-04-29 18:41:10 -0400 |
| commit | b0336e8d2108e6302aecaadd17c6c0bd686da22d (patch) | |
| tree | 063ec0bc590950b7ca0e2c5d5ed8a1c259ce1675 /fs/ext4/dir.c | |
| parent | dbe89444042ab6540bc304343cfdcbc8b95d003d (diff) | |
| download | lwn-b0336e8d2108e6302aecaadd17c6c0bd686da22d.tar.gz lwn-b0336e8d2108e6302aecaadd17c6c0bd686da22d.zip | |
ext4: calculate and verify checksums of directory leaf blocks
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@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/dir.c')
| -rw-r--r-- | fs/ext4/dir.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index b86786202643..aa39e600d159 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -179,6 +179,18 @@ 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 |