nilfs2: support contiguous lookup of blocks
Although get_block() callback function can return extent of contiguous
blocks with bh->b_size, nilfs_get_block() function did not support
this feature.
This adds contiguous lookup feature to the block mapping codes of
nilfs, and allows the nilfs_get_blocks() function to return the extent
information by applying the feature.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 24395e6..aa41272 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -29,6 +29,7 @@
#include "btnode.h"
#include "btree.h"
#include "alloc.h"
+#include "dat.h"
/**
* struct nilfs_btree_path - A path on which B-tree operations are executed
@@ -595,6 +596,87 @@
return ret;
}
+static int nilfs_btree_lookup_contig(const struct nilfs_bmap *bmap,
+ __u64 key, __u64 *ptrp, unsigned maxblocks)
+{
+ struct nilfs_btree *btree = (struct nilfs_btree *)bmap;
+ struct nilfs_btree_path *path;
+ struct nilfs_btree_node *node;
+ struct inode *dat = NULL;
+ __u64 ptr, ptr2;
+ sector_t blocknr;
+ int level = NILFS_BTREE_LEVEL_NODE_MIN;
+ int ret, cnt, index, maxlevel;
+
+ path = nilfs_btree_alloc_path(btree);
+ if (path == NULL)
+ return -ENOMEM;
+ nilfs_btree_init_path(btree, path);
+ ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level);
+ if (ret < 0)
+ goto out;
+
+ if (NILFS_BMAP_USE_VBN(bmap)) {
+ dat = nilfs_bmap_get_dat(bmap);
+ ret = nilfs_dat_translate(dat, ptr, &blocknr);
+ if (ret < 0)
+ goto out;
+ ptr = blocknr;
+ }
+ cnt = 1;
+ if (cnt == maxblocks)
+ goto end;
+
+ maxlevel = nilfs_btree_height(btree) - 1;
+ node = nilfs_btree_get_node(btree, path, level);
+ index = path[level].bp_index + 1;
+ for (;;) {
+ while (index < nilfs_btree_node_get_nchildren(btree, node)) {
+ if (nilfs_btree_node_get_key(btree, node, index) !=
+ key + cnt)
+ goto end;
+ ptr2 = nilfs_btree_node_get_ptr(btree, node, index);
+ if (dat) {
+ ret = nilfs_dat_translate(dat, ptr2, &blocknr);
+ if (ret < 0)
+ goto out;
+ ptr2 = blocknr;
+ }
+ if (ptr2 != ptr + cnt || ++cnt == maxblocks)
+ goto end;
+ index++;
+ continue;
+ }
+ if (level == maxlevel)
+ break;
+
+ /* look-up right sibling node */
+ node = nilfs_btree_get_node(btree, path, level + 1);
+ index = path[level + 1].bp_index + 1;
+ if (index >= nilfs_btree_node_get_nchildren(btree, node) ||
+ nilfs_btree_node_get_key(btree, node, index) != key + cnt)
+ break;
+ ptr2 = nilfs_btree_node_get_ptr(btree, node, index);
+ path[level + 1].bp_index = index;
+
+ brelse(path[level].bp_bh);
+ path[level].bp_bh = NULL;
+ ret = nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh);
+ if (ret < 0)
+ goto out;
+ node = nilfs_btree_get_nonroot_node(btree, path, level);
+ index = 0;
+ path[level].bp_index = index;
+ }
+ end:
+ *ptrp = ptr;
+ ret = cnt;
+ out:
+ nilfs_btree_clear_path(btree, path);
+ nilfs_btree_free_path(btree, path);
+ return ret;
+}
+
static void nilfs_btree_promote_key(struct nilfs_btree *btree,
struct nilfs_btree_path *path,
int level, __u64 key)
@@ -2187,6 +2269,7 @@
static const struct nilfs_bmap_operations nilfs_btree_ops = {
.bop_lookup = nilfs_btree_lookup,
+ .bop_lookup_contig = nilfs_btree_lookup_contig,
.bop_insert = nilfs_btree_insert,
.bop_delete = nilfs_btree_delete,
.bop_clear = NULL,
@@ -2206,6 +2289,7 @@
static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
.bop_lookup = NULL,
+ .bop_lookup_contig = NULL,
.bop_insert = NULL,
.bop_delete = NULL,
.bop_clear = NULL,