/*
* If the superblock has the CRC feature bit set or the CRC field is non-null,
* check that the CRC is valid. We check the CRC field is non-null because a
* single bit error could clear the feature bit and unused parts of the
* superblock are supposed to be zero. Hence a non-null crc field indicates that
* we've potentially lost a feature bit and we should check it anyway.
*
* However, past bugs (i.e. in growfs) left non-zeroed regions beyond the
* last field in V4 secondary superblocks. So for secondary superblocks,
* we are more forgiving, and ignore CRC failures if the primary doesn't
* indicate that the fs version is V5.
*/
static void
xfs_sb_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_dsb *dsb = XFS_BUF_TO_SBP(bp);
int error;
/*
* open code the version check to avoid needing to convert the entire
* superblock from disk order just to check the version number
*/
if (dsb->sb_magicnum == cpu_to_be32(XFS_SB_MAGIC) &&
(((be16_to_cpu(dsb->sb_versionnum) & XFS_SB_VERSION_NUMBITS) ==
XFS_SB_VERSION_5) ||
dsb->sb_crc != 0)) {
if (!xfs_buf_verify_cksum(bp, XFS_SB_CRC_OFF)) {
/* Only fail bad secondaries on a known V5 filesystem */
if (bp->b_bn == XFS_SB_DADDR ||
xfs_sb_version_hascrc(&mp->m_sb)) {
error = -EFSBADCRC;
goto out_error;
}
}
}
error = xfs_sb_verify(bp, true);
out_error:
if (error) {
xfs_buf_ioerror(bp, error);
if (error == -EFSCORRUPTED || error == -EFSBADCRC)
xfs_verifier_error(bp);
}
}
static void
xfs_dir3_block_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
if (xfs_sb_version_hascrc(&mp->m_sb) &&
!xfs_buf_verify_cksum(bp, XFS_DIR3_DATA_CRC_OFF))
xfs_buf_ioerror(bp, -EFSBADCRC);
else if (!xfs_dir3_block_verify(bp))
xfs_buf_ioerror(bp, -EFSCORRUPTED);
if (bp->b_error)
xfs_verifier_error(bp);
}
static void
xfs_symlink_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
xfs_failaddr_t fa;
/* no verification of non-crc buffers */
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
if (!xfs_buf_verify_cksum(bp, XFS_SYMLINK_CRC_OFF))
xfs_verifier_error(bp, -EFSBADCRC, __this_address);
else {
fa = xfs_symlink_verify(bp);
if (fa)
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
}
}
