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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2020-09-10 00:21:06 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-30 12:38:30 +0300 |
| commit | e004f8f381e383a32b4df0eec60cc9813864cd92 (patch) | |
| tree | 6646106f903f53d94753619f0c290470061f66b8 | |
| parent | 7a1e074bc18d32718edcde0a0ad75fff262a4410 (diff) | |
| download | linux-e004f8f381e383a32b4df0eec60cc9813864cd92.tar.xz | |
xfs: make sure the rt allocator doesn't run off the end
[ Upstream commit 2a6ca4baed620303d414934aa1b7b0a8e7bab05f ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 484eb0adcefb..08da48b66235 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -245,6 +245,9 @@ 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. @@ -440,6 +443,14 @@ 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. */ |