xfs: limit specualtive delalloc to maxioffset

Speculative delayed allocation beyond EOF near the maximum supported
file offset can result in creating delalloc extents beyond
mp->m_maxioffset (8EB). These can never be trimmed during
xfs_free_eof_blocks() because they are beyond mp->m_maxioffset, and
that results in assert failures in xfs_fs_destroy_inode() due to
delalloc blocks still being present. xfstests 071 exposes this
problem.

Limit speculative delalloc to mp->m_maxioffset to avoid this
problem.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 47e714a7bf921ba0338b7ad6bf1598b420972d7f..7aa0c1de2e057901952aa92953ce772325e1cd77 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -415,6 +415,15 @@ retry:
                        return error;
        }
 
+       /*
+        * Make sure preallocation does not create extents beyond the range we
+        * actually support in this filesystem.
+        */
+       if (last_fsb > XFS_B_TO_FSB(mp, mp->m_maxioffset))
+               last_fsb = XFS_B_TO_FSB(mp, mp->m_maxioffset);
+
+       ASSERT(last_fsb > offset_fsb);
+
        nimaps = XFS_WRITE_IMAPS;
        error = xfs_bmapi_delay(ip, offset_fsb, last_fsb - offset_fsb,
                                imap, &nimaps, XFS_BMAPI_ENTIRE);