xfs: overflow in xfs_iomap_eof_align_last_fsb

If extsize is set and new_last_fsb is larger than 32 bits, the
roundup to extsize will overflow the align variable. Instead,
combine alignments by rounding stripe size up to extsize.

Signed-off-by: Peter Watkins <treestem@gmail.com>
Reviewed-by: Nathaniel W. Turner <nate@houseofnate.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index afcf3c926565..3fad07136c5d 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -52,7 +52,6 @@ xfs_iomap_eof_align_last_fsb(
         xfs_extlen_t    extsize,
         xfs_fileoff_t   *last_fsb)
 {
-        xfs_fileoff_t   new_last_fsb = 0;
         xfs_extlen_t    align = 0;
         int             eof, error;
 
@@ -70,8 +69,8 @@ xfs_iomap_eof_align_last_fsb(
                 else if (mp->m_dalign)
                         align = mp->m_dalign;
 
-                if (align && XFS_ISIZE(ip) >= XFS_FSB_TO_B(mp, align))
-                        new_last_fsb = roundup_64(*last_fsb, align);
+                if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
+                        align = 0;
         }
 
         /*
@@ -79,14 +78,14 @@ xfs_iomap_eof_align_last_fsb(
          * (when file on a real-time subvolume or has di_extsize hint).
          */
         if (extsize) {
-                if (new_last_fsb)
-                        align = roundup_64(new_last_fsb, extsize);
+                if (align)
+                        align = roundup_64(align, extsize);
                 else
                         align = extsize;
-                new_last_fsb = roundup_64(*last_fsb, align);
         }
 
-        if (new_last_fsb) {
+        if (align) {
+                xfs_fileoff_t   new_last_fsb = roundup_64(*last_fsb, align);
                 error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
                 if (error)
                         return error;