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Commit 3702ce6e authored by Dave Chinner's avatar Dave Chinner Committed by Ben Myers
Browse files

xfs: verify AGI blocks as they are read from disk 



Add an AGI block verify callback function and pass it into the
buffer read functions. Remove the now redundant verification code
that is currently in use.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarBen Myers <bpm@sgi.com>
parent 5d5f527d

fs/xfs/xfs_ialloc.c

+35 −21
Original line number Diff line number Diff line
@@ -1472,6 +1472,40 @@ xfs_check_agi_unlinked( 
#define xfs_check_agi_unlinked(agi)

#endif



static void

xfs_agi_read_verify(

	struct xfs_buf	*bp)

{

	struct xfs_mount *mp = bp->b_target->bt_mount;

	struct xfs_agi	*agi = XFS_BUF_TO_AGI(bp);

	int		agi_ok;



	/*

	 * Validate the magic number of the agi block.

	 */

	agi_ok = agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC) &&

		XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum));



	/*

	 * during growfs operations, the perag is not fully initialised,

	 * so we can't use it for any useful checking. growfs ensures we can't

	 * use it by using uncached buffers that don't have the perag attached

	 * so we can detect and avoid this problem.

	 */

	if (bp->b_pag)

		agi_ok = agi_ok && be32_to_cpu(agi->agi_seqno) ==

						bp->b_pag->pag_agno;



	if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,

			XFS_RANDOM_IALLOC_READ_AGI))) {

		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, agi);

		xfs_buf_ioerror(bp, EFSCORRUPTED);

	}

	xfs_check_agi_unlinked(agi);

	bp->b_iodone = NULL;

	xfs_buf_ioend(bp, 0);

}



/*

 * Read in the allocation group header (inode allocation section)

 */
@@ -1482,38 +1516,18 @@ xfs_read_agi( 
	xfs_agnumber_t		agno,	/* allocation group number */

	struct xfs_buf		**bpp)	/* allocation group hdr buf */

{

	struct xfs_agi		*agi;	/* allocation group header */

	int			agi_ok;	/* agi is consistent */

	int			error;



	ASSERT(agno != NULLAGNUMBER);



	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,

			XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),

			XFS_FSS_TO_BB(mp, 1), 0, bpp, NULL);

			XFS_FSS_TO_BB(mp, 1), 0, bpp, xfs_agi_read_verify);

	if (error)

		return error;



	ASSERT(!xfs_buf_geterror(*bpp));

	agi = XFS_BUF_TO_AGI(*bpp);



	/*

	 * Validate the magic number of the agi block.

	 */

	agi_ok = agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC) &&

		XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum)) &&

		be32_to_cpu(agi->agi_seqno) == agno;

	if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,

			XFS_RANDOM_IALLOC_READ_AGI))) {

		XFS_CORRUPTION_ERROR("xfs_read_agi", XFS_ERRLEVEL_LOW,

				     mp, agi);

		xfs_trans_brelse(tp, *bpp);

		return XFS_ERROR(EFSCORRUPTED);

	}



	xfs_buf_set_ref(*bpp, XFS_AGI_REF);



	xfs_check_agi_unlinked(agi);

	return 0;

}