ext4: Make the extent validity check more paranoid

[deliverable/linux.git] / fs / ext4 / extents.c

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 6132353dcf62a5a167d62d6d34f2343fd5a4533a..c28ffe2595066b903a182dfc9ab0c175de90006f 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -326,11 +326,14 @@ ext4_ext_max_entries(struct inode *inode, int depth)
 
 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 {
-       ext4_fsblk_t block = ext_pblock(ext);
+       ext4_fsblk_t block = ext_pblock(ext), valid_block;
        int len = ext4_ext_get_actual_len(ext);
        struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
-       if (unlikely(block < le32_to_cpu(es->s_first_data_block) ||
-                       ((block + len) > ext4_blocks_count(es))))
+
+       valid_block = le32_to_cpu(es->s_first_data_block) +
+               EXT4_SB(inode->i_sb)->s_gdb_count;
+       if (unlikely(block <= valid_block ||
+                    ((block + len) > ext4_blocks_count(es))))
                return 0;
        else
                return 1;
@@ -339,10 +342,13 @@ static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 static int ext4_valid_extent_idx(struct inode *inode,
                                struct ext4_extent_idx *ext_idx)
 {
-       ext4_fsblk_t block = idx_pblock(ext_idx);
+       ext4_fsblk_t block = idx_pblock(ext_idx), valid_block;
        struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
-       if (unlikely(block < le32_to_cpu(es->s_first_data_block) ||
-                       (block >= ext4_blocks_count(es))))
+
+       valid_block = le32_to_cpu(es->s_first_data_block) +
+               EXT4_SB(inode->i_sb)->s_gdb_count;
+       if (unlikely(block <= valid_block ||
+                    (block >= ext4_blocks_count(es))))
                return 0;
        else
                return 1;