From: "Darrick J. Wong" djwong@kernel.org
commit cf8f0e6c1429be7652869059ea44696b72d5b726 upstream.
It's quite reasonable that some customer somewhere will want to configure a realtime volume with more than 2^32 extents. If they try to do this, the highbit32() call will truncate the upper bits of the xfs_rtbxlen_t and produce the wrong value for rextslog. This in turn causes the rsumlevels to be wrong, which results in a realtime summary file that is the wrong length. Fix that.
Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Catherine Hoang catherine.hoang@oracle.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/libxfs/xfs_rtbitmap.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c index 37b425ea3fed..8db1243beacc 100644 --- a/fs/xfs/libxfs/xfs_rtbitmap.c +++ b/fs/xfs/libxfs/xfs_rtbitmap.c @@ -1133,13 +1133,15 @@ xfs_rtalloc_extent_is_free(
/* * Compute the maximum level number of the realtime summary file, as defined by - * mkfs. The use of highbit32 on a 64-bit quantity is a historic artifact that - * prohibits correct use of rt volumes with more than 2^32 extents. + * mkfs. The historic use of highbit32 on a 64-bit quantity prohibited correct + * use of rt volumes with more than 2^32 extents. */ uint8_t xfs_compute_rextslog( xfs_rtbxlen_t rtextents) { - return rtextents ? xfs_highbit32(rtextents) : 0; + if (!rtextents) + return 0; + return xfs_highbit64(rtextents); }