[PATCH] reiserfs: reorganize bitmap loading functions

[safe/jmp/linux-2.6] / fs / reiserfs / bitmap.c

diff --git a/fs/reiserfs/bitmap.c b/fs/reiserfs/bitmap.c
index 44d9410..abdd6d9 100644 (file)
--- 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;
+}