3 files changed, 16 insertions, 9 deletions

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 3d469d37345e..24bb0b857860 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -621,6 +621,7 @@ struct gfs2_sbd {
         u32 sd_hash_bsize_shift;
         u32 sd_hash_ptrs;       /* Number of pointers in a hash block */
         u32 sd_qc_per_block;
+        u32 sd_blocks_per_bitmap;
         u32 sd_max_dirres;      /* Max blocks needed to add a directory entry */
         u32 sd_max_height;      /* Max height of a file's metadata tree */
         u64 sd_heightsize[GFS2_MAX_META_HEIGHT + 1];
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index e443966c8106..0e3554edb8f2 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -278,6 +278,9 @@ static int gfs2_read_sb(struct gfs2_sbd *sdp, int silent)
         sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
                                 sizeof(struct gfs2_meta_header)) /
                                 sizeof(struct gfs2_quota_change);
+        sdp->sd_blocks_per_bitmap = (sdp->sd_sb.sb_bsize -
+                                     sizeof(struct gfs2_meta_header))
+                * GFS2_NBBY; /* not the rgrp bitmap, subsequent bitmaps only */
 
         /* Compute maximum reservation required to add a entry to a directory */
 
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 38fe18f2f055..669b89b95ccc 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -251,22 +251,25 @@ static u32 gfs2_bitfit(const u8 *buf, const unsigned int len,
 static int gfs2_rbm_from_block(struct gfs2_rbm *rbm, u64 block)
 {
         u64 rblock = block - rbm->rgd->rd_data0;
-        u32 goal = (u32)rblock;
-        int x;
+        u32 x;
 
         if (WARN_ON_ONCE(rblock > UINT_MAX))
                 return -EINVAL;
         if (block >= rbm->rgd->rd_data0 + rbm->rgd->rd_data)
                 return -E2BIG;
 
-        for (x = 0; x < rbm->rgd->rd_length; x++) {
-                rbm->bi = rbm->rgd->rd_bits + x;
-                if (goal < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY) {
-                        rbm->offset = goal - (rbm->bi->bi_start * GFS2_NBBY);
-                        break;
-                }
-        }
+        rbm->bi = rbm->rgd->rd_bits;
+        rbm->offset = (u32)(rblock);
+        /* Check if the block is within the first block */
+        if (rbm->offset < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY)
+                return 0;
 
+        /* Adjust for the size diff between gfs2_meta_header and gfs2_rgrp */
+        rbm->offset += (sizeof(struct gfs2_rgrp) -
+                        sizeof(struct gfs2_meta_header)) * GFS2_NBBY;
+        x = rbm->offset / rbm->rgd->rd_sbd->sd_blocks_per_bitmap;
+        rbm->offset -= x * rbm->rgd->rd_sbd->sd_blocks_per_bitmap;
+        rbm->bi += x;
         return 0;
 }