1 files changed, 88 insertions, 0 deletions

diff --git a/fs/reiserfs/bitmap.c b/fs/reiserfs/bitmap.c
index 44d9410e9d6a..abdd6d9c4558 100644
--- a/fs/reiserfs/bitmap.c
+++ b/fs/reiserfs/bitmap.c
@@ -9,6 +9,7 @@
 #include <linux/buffer_head.h>
 #include <linux/kernel.h>
 #include <linux/pagemap.h>
+#include <linux/vmalloc.h>
 #include <linux/reiserfs_fs_sb.h>
 #include <linux/reiserfs_fs_i.h>
 #include <linux/quotaops.h>
@@ -1285,3 +1286,90 @@ int reiserfs_can_fit_pages(struct super_block *sb	/* superblock of filesystem
 
         return space > 0 ? space : 0;
 }
+
+void reiserfs_cache_bitmap_metadata(struct super_block *sb,
+                                    struct buffer_head *bh,
+                                    struct reiserfs_bitmap_info *info)
+{
+        unsigned long *cur = (unsigned long *)(bh->b_data + bh->b_size);
+
+        info->first_zero_hint = 1 << (sb->s_blocksize_bits + 3);
+
+        while (--cur >= (unsigned long *)bh->b_data) {
+                int base = ((char *)cur - bh->b_data) << 3;
+
+                /* 0 and ~0 are special, we can optimize for them */
+                if (*cur == 0) {
+                        info->first_zero_hint = base;
+                        info->free_count += BITS_PER_LONG;
+                } else if (*cur != ~0L) {       /* A mix, investigate */
+                        int b;
+                        for (b = BITS_PER_LONG - 1; b >= 0; b--) {
+                                if (!reiserfs_test_le_bit(b, cur)) {
+                                        info->first_zero_hint = base + b;
+                                        info->free_count++;
+                                }
+                        }
+                }
+        }
+        /* The first bit must ALWAYS be 1 */
+        BUG_ON(info->first_zero_hint == 0);
+}
+
+struct buffer_head *reiserfs_read_bitmap_block(struct super_block *sb,
+                                               unsigned int bitmap)
+{
+        b_blocknr_t block = (sb->s_blocksize << 3) * bitmap;
+        struct buffer_head *bh;
+
+        /* Way old format filesystems had the bitmaps packed up front.
+         * I doubt there are any of these left, but just in case... */
+        if (unlikely(test_bit(REISERFS_OLD_FORMAT,
+                              &(REISERFS_SB(sb)->s_properties))))
+                block = REISERFS_SB(sb)->s_sbh->b_blocknr + 1 + bitmap;
+        else if (bitmap == 0)
+                block = (REISERFS_DISK_OFFSET_IN_BYTES >> sb->s_blocksize_bits) + 1;
+
+        bh = sb_getblk(sb, block);
+        if (!buffer_uptodate(bh))
+                ll_rw_block(READ, 1, &bh);
+
+        return bh;
+}
+
+int reiserfs_init_bitmap_cache(struct super_block *sb)
+{
+        struct reiserfs_bitmap_info *bitmap;
+        int i;
+
+        bitmap = vmalloc(sizeof (*bitmap) * SB_BMAP_NR(sb));
+        if (bitmap == NULL)
+                return -ENOMEM;
+
+        memset(bitmap, 0, sizeof (*bitmap) * SB_BMAP_NR(sb));
+
+        for (i = 0; i < SB_BMAP_NR(sb); i++)
+                bitmap[i].bh = reiserfs_read_bitmap_block(sb, i);
+
+        /* make sure we have them all */
+        for (i = 0; i < SB_BMAP_NR(sb); i++) {
+                wait_on_buffer(bitmap[i].bh);
+                if (!buffer_uptodate(bitmap[i].bh)) {
+                        reiserfs_warning(sb, "sh-2029: %s: "
+                                         "bitmap block (#%lu) reading failed",
+                                         __FUNCTION__, bitmap[i].bh->b_blocknr);
+                        for (i = 0; i < SB_BMAP_NR(sb); i++)
+                                brelse(bitmap[i].bh);
+                        vfree(bitmap);
+                        return -EIO;
+                }
+        }
+
+        /* Cache the info on the bitmaps before we get rolling */
+        for (i = 0; i < SB_BMAP_NR(sb); i++)
+                reiserfs_cache_bitmap_metadata(sb, bitmap[i].bh, &bitmap[i]);
+
+        SB_AP_BITMAP(sb) = bitmap;
+
+        return 0;
+}