1 files changed, 28 insertions, 16 deletions

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 73b2d528237f..0128010a0874 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -757,7 +757,8 @@ static loff_t ext2_max_size(int bits)
 {
         loff_t res = EXT2_NDIR_BLOCKS;
         int meta_blocks;
-        loff_t upper_limit;
+        unsigned int upper_limit;
+        unsigned int ppb = 1 << (bits-2);
 
         /* This is calculated to be the largest file size for a
          * dense, file such that the total number of
@@ -771,24 +772,34 @@ static loff_t ext2_max_size(int bits)
         /* total blocks in file system block size */
         upper_limit >>= (bits - 9);
 
+        /* Compute how many blocks we can address by block tree */
+        res += 1LL << (bits-2);
+        res += 1LL << (2*(bits-2));
+        res += 1LL << (3*(bits-2));
+        /* Does block tree limit file size? */
+        if (res < upper_limit)
+                goto check_lfs;
 
+        res = upper_limit;
+        /* How many metadata blocks are needed for addressing upper_limit? */
+        upper_limit -= EXT2_NDIR_BLOCKS;
         /* indirect blocks */
         meta_blocks = 1;
+        upper_limit -= ppb;
         /* double indirect blocks */
-        meta_blocks += 1 + (1LL << (bits-2));
-        /* tripple indirect blocks */
-        meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
-
-        upper_limit -= meta_blocks;
-        upper_limit <<= bits;
-
-        res += 1LL << (bits-2);
-        res += 1LL << (2*(bits-2));
-        res += 1LL << (3*(bits-2));
+        if (upper_limit < ppb * ppb) {
+                meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
+                res -= meta_blocks;
+                goto check_lfs;
+        }
+        meta_blocks += 1 + ppb;
+        upper_limit -= ppb * ppb;
+        /* tripple indirect blocks for the rest */
+        meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
+                DIV_ROUND_UP(upper_limit, ppb*ppb);
+        res -= meta_blocks;
+check_lfs:
         res <<= bits;
-        if (res > upper_limit)
-                res = upper_limit;
-
         if (res > MAX_LFS_FILESIZE)
                 res = MAX_LFS_FILESIZE;
 
@@ -1024,8 +1035,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 
-        if (EXT2_INODE_SIZE(sb) == 0)
-                goto cantfind_ext2;
         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
                 goto cantfind_ext2;
@@ -1087,12 +1096,14 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
                                            sizeof(struct buffer_head *),
                                            GFP_KERNEL);
         if (sbi->s_group_desc == NULL) {
+                ret = -ENOMEM;
                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
                 goto failed_mount;
         }
         bgl_lock_init(sbi->s_blockgroup_lock);
         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
         if (!sbi->s_debts) {
+                ret = -ENOMEM;
                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
                 goto failed_mount_group_desc;
         }
@@ -1148,6 +1159,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 #ifdef CONFIG_EXT2_FS_XATTR
         sbi->s_ea_block_cache = ext2_xattr_create_cache();
         if (!sbi->s_ea_block_cache) {
+                ret = -ENOMEM;
                 ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
                 goto failed_mount3;
         }