ext4: Validate extent details only when read from the disk

[safe/jmp/linux-2.6] / fs / ext4 / extents.c

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ee40b7c..ac77d8b 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -429,6 +429,11 @@ corrupted:
 #define ext4_ext_check(inode, eh, depth)       \
        __ext4_ext_check(__func__, inode, eh, depth)
 
+int ext4_ext_check_inode(struct inode *inode)
+{
+       return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
+}
+
 #ifdef EXT_DEBUG
 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 {
@@ -631,9 +636,6 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 
        eh = ext_inode_hdr(inode);
        depth = ext_depth(inode);
-       if (ext4_ext_check(inode, eh, depth))
-               return ERR_PTR(-EIO);
-
 
        /* account possible depth increase */
        if (!path) {
@@ -649,6 +651,8 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
        i = depth;
        /* walk through the tree */
        while (i) {
+               int need_to_validate = 0;
+
                ext_debug("depth %d: num %d, max %d\n",
                          ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 
@@ -657,10 +661,17 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
                path[ppos].p_depth = i;
                path[ppos].p_ext = NULL;
 
-               bh = sb_bread(inode->i_sb, path[ppos].p_block);
-               if (!bh)
+               bh = sb_getblk(inode->i_sb, path[ppos].p_block);
+               if (unlikely(!bh))
                        goto err;
-
+               if (!bh_uptodate_or_lock(bh)) {
+                       if (bh_submit_read(bh) < 0) {
+                               put_bh(bh);
+                               goto err;
+                       }
+                       /* validate the extent entries */
+                       need_to_validate = 1;
+               }
                eh = ext_block_hdr(bh);
                ppos++;
                BUG_ON(ppos > depth);
@@ -668,7 +679,7 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
                path[ppos].p_hdr = eh;
                i--;
 
-               if (ext4_ext_check(inode, eh, i))
+               if (need_to_validate && ext4_ext_check(inode, eh, i))
                        goto err;
        }