fix readahead calculations in xfs_dir2_leaf_getdents()

[safe/jmp/linux-2.6] / fs / xfs / xfs_dir2_leaf.c

diff --git a/fs/xfs/xfs_dir2_leaf.c b/fs/xfs/xfs_dir2_leaf.c
index fa913e4..41ad537 100644 (file)
--- a/fs/xfs/xfs_dir2_leaf.c
+++ b/fs/xfs/xfs_dir2_leaf.c
@@ -854,6 +854,7 @@ xfs_dir2_leaf_getdents(
                         */
                        ra_want = howmany(bufsize + mp->m_dirblksize,
                                          mp->m_sb.sb_blocksize) - 1;
+                       ASSERT(ra_want >= 0);
 
                        /*
                         * If we don't have as many as we want, and we haven't
@@ -1088,7 +1089,8 @@ xfs_dir2_leaf_getdents(
                 */
                ptr += length;
                curoff += length;
-               bufsize -= length;
+               /* bufsize may have just been a guess; don't go negative */
+               bufsize = bufsize > length ? bufsize - length : 0;
        }
 
        /*