xfs: growfs: don't read garbage for new secondary superblocks
authorDave Chinner <dchinner@redhat.com>
Tue, 9 Oct 2012 03:50:52 +0000 (14:50 +1100)
committerBen Myers <bpm@sgi.com>
Fri, 2 Nov 2012 20:42:35 +0000 (15:42 -0500)
commit1375cb65e87b327a8dd4f920c3e3d837fb40e9c2
tree65864cb563db56e2bb8fe2e63f2c21d4e61a01c4
parente04426b9202bccd4cfcbc70b2fa2aeca1c86d8f5
xfs: growfs: don't read garbage for new secondary superblocks

When updating new secondary superblocks in a growfs operation, the
superblock buffer is read from the newly grown region of the
underlying device. This is not guaranteed to be zero, so violates
the underlying assumption that the unused parts of superblocks are
zero filled. Get a new buffer for these secondary superblocks to
ensure that the unused regions are zero filled correctly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
fs/xfs/xfs_fsops.c