ext4: convert block group-relative offsets to use clusters

Certain parts of the ext4 code base, primarily in mballoc.c, use a
block group number and offset from the beginning of the block group.
This offset is invariably used to index into the allocation bitmap, so
change the offset to be denominated in units of clusters.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 1c6d777b35a298a7148de5ef175f5b7f2258d605..89abf1f7b253818e049c7f27b901390de0cc6edb 100644 (file)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -28,7 +28,8 @@
  */
 
 /*
- * Calculate the block group number and offset, given a block number
+ * Calculate the block group number and offset into the block/cluster
+ * allocation bitmap, given a block number
  */
 void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
                ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
@@ -37,7 +38,8 @@ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
        ext4_grpblk_t offset;
 
        blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
-       offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb));
+       offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
+               EXT4_SB(sb)->s_cluster_bits;
        if (offsetp)
                *offsetp = offset;
        if (blockgrpp)

diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 9d4a636b546c529ac993b18e1fe6abb3e99ab9f5..3cdb8aa9f6b79d694968ef4c60bb0e727fd9c0d5 100644 (file)
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -216,6 +216,7 @@ struct ext4_buddy {
 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
                                        struct ext4_free_extent *fex)
 {
-       return ext4_group_first_block_no(sb, fex->fe_group) + fex->fe_start;
+       return ext4_group_first_block_no(sb, fex->fe_group) +
+               (fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
 }
 #endif