[Ocfs2-tools-devel] [PATCH] Change local variable datatype to avoid infinite loop

[Goldwyn Rodrigues]

fsck on large filesystems goes in an infinite loop.
The problem is in verify_bitmap_descs(). i, a local variable is
declared as uint16_t and is compared with
ocfs2_cluster_group_sizes.cgs_cluster_groups which is uint32_t.
When cgs_cluster_groups is greater than 65535, i overflows and wraps
creating an infinite loop of the following:

        for (i = 0, blkno = ost->ost_fs->fs_first_cg_blkno;
             i < cgs.cgs_cluster_groups;
             i++, blkno = i * ocfs2_clusters_to_blocks(ost->ost_fs,
                                                       cgs.cgs_cpg)) {

Signed-off-by: Goldwyn Rodrigues <rgoldwyn at suse.de>
Signed-off-by: Mark Fasheh <mfasheh at suse.com>
---
 fsck.ocfs2/pass0.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: ocfs2-tools/fsck.ocfs2/pass0.c
===================================================================
--- ocfs2-tools.orig/fsck.ocfs2/pass0.c	2009-05-07 03:41:24.000000000 +0200
+++ ocfs2-tools/fsck.ocfs2/pass0.c	2010-07-26 19:16:26.000000000 +0200
@@ -849,7 +849,7 @@ static errcode_t verify_bitmap_descs(o2f
 				     char *buf1, char *buf2)
 {
 	struct ocfs2_cluster_group_sizes cgs;
-	uint16_t i, max_recs;
+	uint16_t max_recs;
 	uint16_t bits, chain;
 	uint64_t blkno;
 	struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *)buf1;
@@ -857,7 +857,7 @@ static errcode_t verify_bitmap_descs(o2f
 	struct chain_state cs;
 	struct ocfs2_chain_rec *rec;
 	ocfs2_bitmap *allowed = NULL, *forbidden = NULL;
-	int was_set;
+	int was_set, i;

 	/* XXX ugh, only used by mark_ */
 	cs.cs_cpg = di->id2.i_chain.cl_cpg;