Commit b94fb2d1 authored by Brian Foster's avatar Brian Foster Committed by Dave Chinner
Browse files

xfs: refactor and open code log record crc check 



Log record CRC verification currently occurs during active log recovery,
immediately before a log record is unpacked. Therefore, the CRC
calculation code is buried within the data unpack function. CRC
verification pass support only needs to go so far as check the CRC, but
this is not easily allowed as the code is currently organized.

Since we now have a new log record processing helper, pull the record
CRC verification code out from the unpack helper and open-code it at the
top of the new process helper. This facilitates the ability to modify
how records are processed based on the type of the current pass. This
patch contains no functional changes.

Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 9d94901f

fs/xfs/xfs_log_recover.c

+26 −46
Original line number Diff line number Diff line
@@ -4118,46 +4118,6 @@ xlog_recover_process_iunlinks( 
	mp->m_dmevmask = mp_dmevmask;

}



/*

 * Upack the log buffer data and crc check it. If the check fails, issue a

 * warning if and only if the CRC in the header is non-zero. This makes the

 * check an advisory warning, and the zero CRC check will prevent failure

 * warnings from being emitted when upgrading the kernel from one that does not

 * add CRCs by default.

 *

 * When filesystems are CRC enabled, this CRC mismatch becomes a fatal log

 * corruption failure

 */

STATIC int

xlog_unpack_data_crc(

	struct xlog_rec_header	*rhead,

	char			*dp,

	struct xlog		*log)

{

	__le32			crc;



	crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));

	if (crc != rhead->h_crc) {

		if (rhead->h_crc || xfs_sb_version_hascrc(&log->l_mp->m_sb)) {

			xfs_alert(log->l_mp,

		"log record CRC mismatch: found 0x%x, expected 0x%x.",

					le32_to_cpu(rhead->h_crc),

					le32_to_cpu(crc));

			xfs_hex_dump(dp, 32);

		}



		/*

		 * If we've detected a log record corruption, then we can't

		 * recover past this point. Abort recovery if we are enforcing

		 * CRC protection by punting an error back up the stack.

		 */

		if (xfs_sb_version_hascrc(&log->l_mp->m_sb))

			return -EFSCORRUPTED;

	}



	return 0;

}



STATIC int

xlog_unpack_data(

	struct xlog_rec_header	*rhead,
@@ -4165,11 +4125,6 @@ xlog_unpack_data( 
	struct xlog		*log)

{

	int			i, j, k;

	int			error;



	error = xlog_unpack_data_crc(rhead, dp, log);

	if (error)

		return error;



	for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&

		  i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
@@ -4191,7 +4146,7 @@ xlog_unpack_data( 
}



/*

 * Unpack and process a log record.

 * CRC check, unpack and process a log record.

 */

STATIC int

xlog_recover_process(
@@ -4202,6 +4157,31 @@ xlog_recover_process( 
	int			pass)

{

	int			error;

	__le32			crc;



	/*

	 * Check the CRC and issue a warning if and only if the CRC in the

	 * header is non-zero. This is an advisory warning and the zero CRC

	 * check prevents warnings from being emitted when upgrading the kernel

	 * from one that does not add CRCs by default.

	 */

	crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));

	if (crc != le32_to_cpu(rhead->h_crc)) {

		if (rhead->h_crc || xfs_sb_version_hascrc(&log->l_mp->m_sb)) {

			xfs_alert(log->l_mp,

		"log record CRC mismatch: found 0x%x, expected 0x%x.",

					le32_to_cpu(rhead->h_crc),

					le32_to_cpu(crc));

			xfs_hex_dump(dp, 32);

		}



		/*

		 * If the filesystem is CRC enabled, this mismatch becomes a

		 * fatal log corruption failure.

		 */

		if (xfs_sb_version_hascrc(&log->l_mp->m_sb))

			return -EFSCORRUPTED;

	}



	error = xlog_unpack_data(rhead, dp, log);

	if (error)

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