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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2020-09-09 14:21:06 -0700 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2020-09-15 20:52:42 -0700 |
| commit | 2a6ca4baed620303d414934aa1b7b0a8e7bab05f (patch) | |
| tree | a8c41f0884ede6e7a195d371176c26f6434e77bf /fs/xfs/xfs_rtalloc.c | |
| parent | 0f4ec0f157468fdb6512ccd9cd8cbb8b645fb4a0 (diff) | |
| download | linux-2a6ca4baed620303d414934aa1b7b0a8e7bab05f.tar.bz2 | |
xfs: make sure the rt allocator doesn't run off the end
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.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs/xfs_rtalloc.c')
| -rw-r--r-- | fs/xfs/xfs_rtalloc.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index 0558f92ecdb8..5b89c12f1566 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. */ |