Commit 0925fecc authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: fix an integer overflow error in xfs_growfs_rt 



During a realtime grow operation, we run a single transaction for each
rt bitmap block added to the filesystem.  This means that each step has
to be careful to increase sb_rblocks appropriately.

Fix the integer overflow error in this calculation that can happen when
the extent size is very large.  Found by running growfs to add a rt
volume to a filesystem formatted with a 1g rt extent size.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 0e2af929

fs/xfs/xfs_rtalloc.c

+5 −5
Original line number Diff line number Diff line
@@ -1021,7 +1021,8 @@ xfs_growfs_rt( 
		     ((sbp->sb_rextents & ((1 << mp->m_blkbit_log) - 1)) != 0);

	     bmbno < nrbmblocks;

	     bmbno++) {

		xfs_trans_t	*tp;

		struct xfs_trans	*tp;

		xfs_rfsblock_t		nrblocks_step;



		*nmp = *mp;

		nsbp = &nmp->m_sb;
@@ -1030,10 +1031,9 @@ xfs_growfs_rt( 
		 */

		nsbp->sb_rextsize = in->extsize;

		nsbp->sb_rbmblocks = bmbno + 1;

		nsbp->sb_rblocks =

			XFS_RTMIN(nrblocks,

				  nsbp->sb_rbmblocks * NBBY *

				  nsbp->sb_blocksize * nsbp->sb_rextsize);

		nrblocks_step = (bmbno + 1) * NBBY * nsbp->sb_blocksize *

				nsbp->sb_rextsize;

		nsbp->sb_rblocks = min(nrblocks, nrblocks_step);

		nsbp->sb_rextents = nsbp->sb_rblocks;

		do_div(nsbp->sb_rextents, nsbp->sb_rextsize);

		ASSERT(nsbp->sb_rextents != 0);