Btrfs: keep track of the extents original block length

If we've written to a prealloc extent we need to know the original block len
for the extent.  We can't figure this out currently since ->block_len is
just set to the extent length.  So introduce ->orig_block_len so that we
know how many bytes were in the original extent for proper extent logging
that future patches will need.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7855aac36706..bfd59bcc50d7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -699,6 +699,7 @@ retry:
 
                 em->block_start = ins.objectid;
                 em->block_len = ins.offset;
+                em->orig_block_len = ins.offset;
                 em->bdev = root->fs_info->fs_devices->latest_bdev;
                 em->compress_type = async_extent->compress_type;
                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
@@ -886,6 +887,7 @@ static noinline int __cow_file_range(struct btrfs_trans_handle *trans,
 
                 em->block_start = ins.objectid;
                 em->block_len = ins.offset;
+                em->orig_block_len = ins.offset;
                 em->bdev = root->fs_info->fs_devices->latest_bdev;
                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 
@@ -1143,6 +1145,7 @@ static noinline int run_delalloc_nocow(struct inode *inode,
         u64 extent_offset;
         u64 disk_bytenr;
         u64 num_bytes;
+        u64 disk_num_bytes;
         int extent_type;
         int ret, err;
         int type;
@@ -1245,6 +1248,8 @@ next_slot:
                         extent_offset = btrfs_file_extent_offset(leaf, fi);
                         extent_end = found_key.offset +
                                 btrfs_file_extent_num_bytes(leaf, fi);
+                        disk_num_bytes =
+                                btrfs_file_extent_disk_num_bytes(leaf, fi);
                         if (extent_end <= start) {
                                 path->slots[0]++;
                                 goto next_slot;
@@ -1319,6 +1324,7 @@ out_check:
                         em->len = num_bytes;
                         em->block_len = num_bytes;
                         em->block_start = disk_bytenr;
+                        em->orig_block_len = disk_num_bytes;
                         em->bdev = root->fs_info->fs_devices->latest_bdev;
                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
                         set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
@@ -3696,6 +3702,7 @@ int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
 
                         hole_em->block_start = EXTENT_MAP_HOLE;
                         hole_em->block_len = 0;
+                        hole_em->orig_block_len = 0;
                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
                         hole_em->generation = trans->transid;
@@ -5374,6 +5381,8 @@ again:
                 em->len = extent_end - extent_start;
                 em->orig_start = extent_start -
                                  btrfs_file_extent_offset(leaf, item);
+                em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf,
+                                                                      item);
                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
                 if (bytenr == 0) {
                         em->block_start = EXTENT_MAP_HOLE;
@@ -5383,8 +5392,7 @@ again:
                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
                         em->compress_type = compress_type;
                         em->block_start = bytenr;
-                        em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
-                                                                         item);
+                        em->block_len = em->orig_block_len;
                 } else {
                         bytenr += btrfs_file_extent_offset(leaf, item);
                         em->block_start = bytenr;
@@ -5414,6 +5422,7 @@ again:
                 em->start = extent_start + extent_offset;
                 em->len = (copy_size + root->sectorsize - 1) &
                         ~((u64)root->sectorsize - 1);
+                em->orig_block_len = em->len;
                 em->orig_start = EXTENT_MAP_INLINE;
                 if (compress_type) {
                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
@@ -5721,6 +5730,7 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
 
         em->block_start = ins.objectid;
         em->block_len = ins.offset;
+        em->orig_block_len = ins.offset;
         em->bdev = root->fs_info->fs_devices->latest_bdev;
 
         /*
@@ -5914,7 +5924,7 @@ static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
                                            u64 len, u64 orig_start,
                                            u64 block_start, u64 block_len,
-                                           int type)
+                                           u64 orig_block_len, int type)
 {
         struct extent_map_tree *em_tree;
         struct extent_map *em;
@@ -5932,6 +5942,7 @@ static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
         em->block_len = block_len;
         em->block_start = block_start;
         em->bdev = root->fs_info->fs_devices->latest_bdev;
+        em->orig_block_len = orig_block_len;
         set_bit(EXTENT_FLAG_PINNED, &em->flags);
         if (type == BTRFS_ORDERED_PREALLOC)
                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
@@ -6068,12 +6079,14 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
 
                 if (can_nocow_odirect(trans, inode, start, len) == 1) {
                         u64 orig_start = em->start;
+                        u64 orig_block_len = em->orig_block_len;
 
                         if (type == BTRFS_ORDERED_PREALLOC) {
                                 free_extent_map(em);
                                 em = create_pinned_em(inode, start, len,
                                                        orig_start,
-                                                       block_start, len, type);
+                                                       block_start, len,
+                                                       orig_block_len, type);
                                 if (IS_ERR(em)) {
                                         btrfs_end_transaction(trans, root);
                                         goto unlock_err;
@@ -7771,6 +7784,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
                 em->len = ins.offset;
                 em->block_start = ins.objectid;
                 em->block_len = ins.offset;
+                em->orig_block_len = ins.offset;
                 em->bdev = root->fs_info->fs_devices->latest_bdev;
                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
                 em->generation = trans->transid;