[Ocfs2-tools-devel] [PATCH 9/9] dx_dirs: fix ocfs2_swap_dx_entry_list() for big endian

[Coly Li]

As Tao Ma suggested, current ocfs2_swap_dx_entry_list() is
buggy for big endian hardware, because after dl_list->de_count
swapped, it is referenced in the following loop.

This patch fixes this bug with adding an 'int to_cpu' argument, also
modifies other routines who call ocfs2_swap_dx_entry_list().

Signed-off-by: Coly Li <coly.li at suse.de>
Cc: Mark Fasheh <mfasheh at suse.com>
Cc: Tao Ma <tao.ma at oracle.com>
---
 libocfs2/dirblock.c |   23 ++++++++++++++---------
 1 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/libocfs2/dirblock.c b/libocfs2/dirblock.c
index c22d843..e128d73 100644
--- a/libocfs2/dirblock.c
+++ b/libocfs2/dirblock.c
@@ -245,29 +245,34 @@ static void ocfs2_swap_dx_entry(struct ocfs2_dx_entry *dx_entry)
 	dx_entry->dx_dirent_blk		= bswap_64(dx_entry->dx_dirent_blk);
 }

-static void ocfs2_swap_dx_entry_list(struct ocfs2_dx_entry_list *dl_list)
+/* called for big endian */
+static void ocfs2_swap_dx_entry_list(struct ocfs2_dx_entry_list *dl_list, int to_cpu)
 {
 	int i;

-	dl_list->de_count	= bswap_16(dl_list->de_count);
-	dl_list->de_num_used	= bswap_16(dl_list->de_num_used);
+	if (to_cpu)
+		dl_list->de_count = bswap_16(dl_list->de_count);

 	for (i = 0; i < dl_list->de_count; i++)
 		ocfs2_swap_dx_entry(&dl_list->de_entries[i]);
+	dl_list->de_num_used = bswap_16(dl_list->de_num_used);
+
+	if (!to_cpu)
+		dl_list->de_count = bswap_16(dl_list->de_count);
 }

 static void ocfs2_swap_dx_entry_list_to_cpu(struct ocfs2_dx_entry_list *dl_list)
 {
 	if (cpu_is_little_endian)
 		return;
-	ocfs2_swap_dx_entry_list(dl_list);
+	ocfs2_swap_dx_entry_list(dl_list, 1);
 }

 static void ocfs2_swap_dx_entry_list_from_cpu(struct ocfs2_dx_entry_list *dl_list)
 {
 	if (cpu_is_little_endian)
 		return;
-	ocfs2_swap_dx_entry_list(dl_list);
+	ocfs2_swap_dx_entry_list(dl_list, 0);
 }

 static void ocfs2_swap_dx_root_to_cpu(ocfs2_filesys *fs,
@@ -384,26 +389,26 @@ out:
 	return ret;
 }

-static void ocfs2_swap_dx_leaf(struct ocfs2_dx_leaf *dx_leaf)
+static void ocfs2_swap_dx_leaf(struct ocfs2_dx_leaf *dx_leaf, int to_cpu)
 {
 	dx_leaf->dl_blkno = bswap_64(dx_leaf->dl_blkno);
 	dx_leaf->dl_fs_generation = bswap_64(dx_leaf->dl_fs_generation);

-	ocfs2_swap_dx_entry_list(&dx_leaf->dl_list);
+	ocfs2_swap_dx_entry_list(&dx_leaf->dl_list, to_cpu);
 }

 static void ocfs2_swap_dx_leaf_to_cpu(struct ocfs2_dx_leaf *dx_leaf)
 {
 	if (cpu_is_little_endian)
 		return;
-	ocfs2_swap_dx_leaf(dx_leaf);
+	ocfs2_swap_dx_leaf(dx_leaf, 1);
 }

 static void ocfs2_swap_dx_leaf_from_cpu(struct ocfs2_dx_leaf *dx_leaf)
 {
 	if (cpu_is_little_endian)
 		return;
-	ocfs2_swap_dx_leaf(dx_leaf);
+	ocfs2_swap_dx_leaf(dx_leaf, 0);
 }

 errcode_t ocfs2_read_dx_leaf(ocfs2_filesys *fs, uint64_t block,
-- 
1.7.0.2