Message ID | 159950167474.582172.16930353017934744381.stgit@magnolia (mailing list archive) |
---|---|
State | Accepted |
Headers | show |
Series | xfs: fix a few realtime bugs | expand |
On Mon, Sep 07, 2020 at 11:01:14AM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > There's an overflow bug in the realtime allocator. If the rt volume is > large enough to handle a single allocation request that is larger than > the maximum bmap extent length and the rt bitmap ends exactly on a > bitmap block boundary, it's possible that the near allocator will try to > check the freeness of a range that extends past the end of the bitmap. > This fails with a corruption error and shuts down the fs. > > Therefore, constrain maxlen so that the range scan cannot run off the > end of the rt bitmap. Looks good, Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index 6209e7b6b895..86994d7f7cba 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -247,6 +247,9 @@ xfs_rtallocate_extent_block( end = XFS_BLOCKTOBIT(mp, bbno + 1) - 1; i <= end; i++) { + /* Make sure we don't scan off the end of the rt volume. */ + maxlen = min(mp->m_sb.sb_rextents, i + maxlen) - i; + /* * See if there's a free extent of maxlen starting at i. * If it's not so then next will contain the first non-free. @@ -442,6 +445,14 @@ xfs_rtallocate_extent_near( */ if (bno >= mp->m_sb.sb_rextents) bno = mp->m_sb.sb_rextents - 1; + + /* Make sure we don't run off the end of the rt volume. */ + maxlen = min(mp->m_sb.sb_rextents, bno + maxlen) - bno; + if (maxlen < minlen) { + *rtblock = NULLRTBLOCK; + return 0; + } + /* * Try the exact allocation first. */