address hfs on-disk corruption robustness review comments

Address Roman's review comments for the previously sent on-disk
corruption hfs robustness patch.

- use 0 as a failure value, rather than making a new macro HFS_BAD_KEYLEN,
  and use a switch statement instead of if's.

- Add new fail: target to __hfs_brec_find to skip assignments using bad
  values when exiting with a failure.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 25 insertions, 18 deletions

diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
index f8452a0eab56..4129cdb3f0d8 100644
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -52,9 +52,9 @@ int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd)
                 rec = (e + b) / 2;
                 len = hfs_brec_lenoff(bnode, rec, &off);
                 keylen = hfs_brec_keylen(bnode, rec);
-                if (keylen == HFS_BAD_KEYLEN) {
+                if (keylen == 0) {
                         res = -EINVAL;
-                        goto done;
+                        goto fail;
                 }
                 hfs_bnode_read(bnode, fd->key, off, keylen);
                 cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
@@ -71,9 +71,9 @@ int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd)
         if (rec != e && e >= 0) {
                 len = hfs_brec_lenoff(bnode, e, &off);
                 keylen = hfs_brec_keylen(bnode, e);
-                if (keylen == HFS_BAD_KEYLEN) {
+                if (keylen == 0) {
                         res = -EINVAL;
-                        goto done;
+                        goto fail;
                 }
                 hfs_bnode_read(bnode, fd->key, off, keylen);
         }
@@ -83,6 +83,7 @@ done:
         fd->keylength = keylen;
         fd->entryoffset = off + keylen;
         fd->entrylength = len - keylen;
+fail:
         return res;
 }
 
@@ -206,7 +207,7 @@ int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
 
         len = hfs_brec_lenoff(bnode, fd->record, &off);
         keylen = hfs_brec_keylen(bnode, fd->record);
-        if (keylen == HFS_BAD_KEYLEN) {
+        if (keylen == 0) {
                 res = -EINVAL;
                 goto out;
         }
diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c
index 8626ee375ea8..878bf25dbc6a 100644
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -49,14 +49,14 @@ u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
                         if (retval > node->tree->max_key_len + 2) {
                                 printk(KERN_ERR "hfs: keylen %d too large\n",
                                         retval);
-                                retval = HFS_BAD_KEYLEN;
+                                retval = 0;
                         }
                 } else {
                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
                         if (retval > node->tree->max_key_len + 1) {
                                 printk(KERN_ERR "hfs: keylen %d too large\n",
                                         retval);
-                                retval = HFS_BAD_KEYLEN;
+                                retval = 0;
                         }
                 }
         }
diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 110dd3515dc8..24cf6fc43021 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -81,15 +81,23 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp ke
                 goto fail_page;
         if (!tree->node_count)
                 goto fail_page;
-        if ((id == HFS_EXT_CNID) && (tree->max_key_len != HFS_MAX_EXT_KEYLEN)) {
-                printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
-                        tree->max_key_len);
-                goto fail_page;
-        }
-        if ((id == HFS_CAT_CNID) && (tree->max_key_len != HFS_MAX_CAT_KEYLEN)) {
-                printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
-                        tree->max_key_len);
-                goto fail_page;
+        switch (id) {
+        case HFS_EXT_CNID:
+                if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
+                        printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
+                                tree->max_key_len);
+                        goto fail_page;
+                }
+                break;
+        case HFS_CAT_CNID:
+                if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
+                        printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
+                                tree->max_key_len);
+                        goto fail_page;
+                }
+                break;
+        default:
+                BUG();
         }
 
         tree->node_size_shift = ffs(size) - 1;
diff --git a/fs/hfs/hfs.h b/fs/hfs/hfs.h
index c6aae61adfe6..6f194d0768b6 100644
--- a/fs/hfs/hfs.h
+++ b/fs/hfs/hfs.h
@@ -28,8 +28,6 @@
 #define HFS_MAX_NAMELEN         128
 #define HFS_MAX_VALENCE         32767U
 
-#define HFS_BAD_KEYLEN          0xFF
-
 /* Meanings of the drAtrb field of the MDB,
  * Reference: _Inside Macintosh: Files_ p. 2-61
  */