ext4: use more strict checks for inodes_per_block on mount

commit cd6bb35bf7f6d7d922509bf50265383a0ceabe96 upstream.

Centralize the checks for inodes_per_block and be more strict to make
sure the inodes_per_block_group can't end up being zero.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index df53221..3fc028d 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3541,12 +3541,16 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
-       if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
-               goto cantfind_ext4;
 
        sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
        if (sbi->s_inodes_per_block == 0)
                goto cantfind_ext4;
+       if (sbi->s_inodes_per_group < sbi->s_inodes_per_block ||
+           sbi->s_inodes_per_group > blocksize * 8) {
+               ext4_msg(sb, KERN_ERR, "invalid inodes per group: %lu\n",
+                        sbi->s_blocks_per_group);
+               goto failed_mount;
+       }
        sbi->s_itb_per_group = sbi->s_inodes_per_group /
                                        sbi->s_inodes_per_block;
        sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
@@ -3625,13 +3629,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        }
        sbi->s_cluster_ratio = clustersize / blocksize;
 
-       if (sbi->s_inodes_per_group > blocksize * 8) {
-               ext4_msg(sb, KERN_ERR,
-                      "#inodes per group too big: %lu",
-                      sbi->s_inodes_per_group);
-               goto failed_mount;
-       }
-
        /*
         * Test whether we have more sectors than will fit in sector_t,
         * and whether the max offset is addressable by the page cache.