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nilfs2: support contiguous lookup of blocks

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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>
This commit is contained in:
Ryusuke Konishi
2009-05-25 02:47:14 +09:00
parent fa032744ad
commit c3a7abf06c
5 changed files with 150 additions and 8 deletions
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84
fs/nilfs2/btree.c
View File

@@ -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 @@ static int nilfs_btree_lookup(const struct nilfs_bmap *bmap,
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 int nilfs_btree_mark(struct nilfs_bmap *bmap, __u64 key, int level)
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 = {
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,