ext4: fix the free blocks calculation for ext3 file systems w/ uninit_bg

[pandora-kernel.git] / fs / ext4 / balloc.c

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index c45c411..cee7812 100644 (file)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -90,8 +90,8 @@ unsigned ext4_num_overhead_clusters(struct super_block *sb,
         * unusual file system layouts.
         */
        if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
-               block_cluster = EXT4_B2C(sbi, (start -
-                                              ext4_block_bitmap(sb, gdp)));
+               block_cluster = EXT4_B2C(sbi,
+                                        ext4_block_bitmap(sb, gdp) - start);
                if (block_cluster < num_clusters)
                        block_cluster = -1;
                else if (block_cluster == num_clusters) {
@@ -102,7 +102,7 @@ unsigned ext4_num_overhead_clusters(struct super_block *sb,
 
        if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
                inode_cluster = EXT4_B2C(sbi,
-                                        start - ext4_inode_bitmap(sb, gdp));
+                                        ext4_inode_bitmap(sb, gdp) - start);
                if (inode_cluster < num_clusters)
                        inode_cluster = -1;
                else if (inode_cluster == num_clusters) {
@@ -114,7 +114,7 @@ unsigned ext4_num_overhead_clusters(struct super_block *sb,
        itbl_blk = ext4_inode_table(sb, gdp);
        for (i = 0; i < sbi->s_itb_per_group; i++) {
                if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
-                       c = EXT4_B2C(sbi, start - itbl_blk + i);
+                       c = EXT4_B2C(sbi, itbl_blk + i - start);
                        if ((c < num_clusters) || (c == inode_cluster) ||
                            (c == block_cluster) || (c == itbl_cluster))
                                continue;
@@ -168,12 +168,14 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 
        /* If checksum is bad mark all blocks used to prevent allocation
         * essentially implementing a per-group read-only flag. */
-       if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
+       if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
                ext4_error(sb, "Checksum bad for group %u", block_group);
                ext4_free_group_clusters_set(sb, gdp, 0);
                ext4_free_inodes_set(sb, gdp, 0);
                ext4_itable_unused_set(sb, gdp, 0);
                memset(bh->b_data, 0xff, sb->s_blocksize);
+               ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
+                                          EXT4_BLOCKS_PER_GROUP(sb) / 8);
                return;
        }
        memset(bh->b_data, 0, sb->s_blocksize);
@@ -210,6 +212,9 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
         */
        ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
                             sb->s_blocksize * 8, bh->b_data);
+       ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
+                                  EXT4_BLOCKS_PER_GROUP(sb) / 8);
+       ext4_group_desc_csum_set(sb, block_group, gdp);
 }
 
 /* Return the number of free blocks in a block group.  It is used when
@@ -276,9 +281,9 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
 }
 
 static int ext4_valid_block_bitmap(struct super_block *sb,
-                                       struct ext4_group_desc *desc,
-                                       unsigned int block_group,
-                                       struct buffer_head *bh)
+                                  struct ext4_group_desc *desc,
+                                  unsigned int block_group,
+                                  struct buffer_head *bh)
 {
        ext4_grpblk_t offset;
        ext4_grpblk_t next_zero_bit;
@@ -325,6 +330,23 @@ err_out:
                        block_group, bitmap_blk);
        return 0;
 }
+
+void ext4_validate_block_bitmap(struct super_block *sb,
+                              struct ext4_group_desc *desc,
+                              unsigned int block_group,
+                              struct buffer_head *bh)
+{
+       if (buffer_verified(bh))
+               return;
+
+       ext4_lock_group(sb, block_group);
+       if (ext4_valid_block_bitmap(sb, desc, block_group, bh) &&
+           ext4_block_bitmap_csum_verify(sb, block_group, desc, bh,
+                                         EXT4_BLOCKS_PER_GROUP(sb) / 8))
+               set_buffer_verified(bh);
+       ext4_unlock_group(sb, block_group);
+}
+
 /**
  * ext4_read_block_bitmap()
  * @sb:                        super block
@@ -355,12 +377,12 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
        }
 
        if (bitmap_uptodate(bh))
-               return bh;
+               goto verify;
 
        lock_buffer(bh);
        if (bitmap_uptodate(bh)) {
                unlock_buffer(bh);
-               return bh;
+               goto verify;
        }
        ext4_lock_group(sb, block_group);
        if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
@@ -379,7 +401,7 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
                 */
                set_bitmap_uptodate(bh);
                unlock_buffer(bh);
-               return bh;
+               goto verify;
        }
        /*
         * submit the buffer_head for reading
@@ -390,6 +412,9 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
        get_bh(bh);
        submit_bh(READ, bh);
        return bh;
+verify:
+       ext4_validate_block_bitmap(sb, desc, block_group, bh);
+       return bh;
 }
 
 /* Returns 0 on success, 1 on error */
@@ -412,7 +437,7 @@ int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
        }
        clear_buffer_new(bh);
        /* Panic or remount fs read-only if block bitmap is invalid */
-       ext4_valid_block_bitmap(sb, desc, block_group, bh);
+       ext4_validate_block_bitmap(sb, desc, block_group, bh);
        return 0;
 }