1 files changed, 17 insertions, 11 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 005c45db699e..1ddd728541ee 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -986,7 +986,7 @@ out:
  * be reclaimed before their checksum is actually put into the btree
  */
 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
-                           u32 *sum)
+                           u32 *sum, int len)
 {
         struct btrfs_ordered_sum *ordered_sum;
         struct btrfs_sector_sum *sector_sums;
@@ -995,22 +995,28 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
         unsigned long num_sectors;
         unsigned long i;
         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
-        int ret = 1;
+        int index = 0;
 
         ordered = btrfs_lookup_ordered_extent(inode, offset);
         if (!ordered)
-                return 1;
+                return 0;
 
         spin_lock_irq(&tree->lock);
         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
-                if (disk_bytenr >= ordered_sum->bytenr) {
-                        num_sectors = ordered_sum->len / sectorsize;
-                        sector_sums = ordered_sum->sums;
-                        for (i = 0; i < num_sectors; i++) {
+                if (disk_bytenr >= ordered_sum->bytenr &&
+                    disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
+                        i = (disk_bytenr - ordered_sum->bytenr) >>
+                            inode->i_sb->s_blocksize_bits;
+                        sector_sums = ordered_sum->sums + i;
+                        num_sectors = ordered_sum->len >>
+                                      inode->i_sb->s_blocksize_bits;
+                        for (; i < num_sectors; i++) {
                                 if (sector_sums[i].bytenr == disk_bytenr) {
-                                        *sum = sector_sums[i].sum;
-                                        ret = 0;
-                                        goto out;
+                                        sum[index] = sector_sums[i].sum;
+                                        index++;
+                                        if (index == len)
+                                                goto out;
+                                        disk_bytenr += sectorsize;
                                 }
                         }
                 }
@@ -1018,7 +1024,7 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
 out:
         spin_unlock_irq(&tree->lock);
         btrfs_put_ordered_extent(ordered);
-        return ret;
+        return index;
 }