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: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2021-07-12 12:58:49 -07:00
parent 0e2af9296f
commit 0925fecc55

View file

@ -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);