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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>
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Ryusuke Konishi committed Jun 10, 2009
1 parent fa03274 commit c3a7abf
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Showing 5 changed files with 150 additions and 8 deletions.
12 changes: 11 additions & 1 deletion fs/nilfs2/bmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@
#include "dat.h"
#include "alloc.h"

static struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *bmap)
struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *bmap)
{
return nilfs_dat_inode(NILFS_I_NILFS(bmap->b_inode));
}
Expand All @@ -58,6 +58,16 @@ int nilfs_bmap_lookup_at_level(struct nilfs_bmap *bmap, __u64 key, int level,
return ret;
}

int nilfs_bmap_lookup_contig(struct nilfs_bmap *bmap, __u64 key, __u64 *ptrp,
unsigned maxblocks)
{
int ret;

down_read(&bmap->b_sem);
ret = bmap->b_ops->bop_lookup_contig(bmap, key, ptrp, maxblocks);
up_read(&bmap->b_sem);
return ret;
}

/**
* nilfs_bmap_lookup - find a record
Expand Down
4 changes: 4 additions & 0 deletions fs/nilfs2/bmap.h
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,8 @@ struct nilfs_bmap_stats {
*/
struct nilfs_bmap_operations {
int (*bop_lookup)(const struct nilfs_bmap *, __u64, int, __u64 *);
int (*bop_lookup_contig)(const struct nilfs_bmap *, __u64, __u64 *,
unsigned);
int (*bop_insert)(struct nilfs_bmap *, __u64, __u64);
int (*bop_delete)(struct nilfs_bmap *, __u64);
void (*bop_clear)(struct nilfs_bmap *);
Expand Down Expand Up @@ -140,6 +142,7 @@ int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
int nilfs_bmap_lookup(struct nilfs_bmap *, unsigned long, unsigned long *);
int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
int nilfs_bmap_insert(struct nilfs_bmap *, unsigned long, unsigned long);
int nilfs_bmap_delete(struct nilfs_bmap *, unsigned long);
int nilfs_bmap_last_key(struct nilfs_bmap *, unsigned long *);
Expand All @@ -160,6 +163,7 @@ void nilfs_bmap_commit_gcdat(struct nilfs_bmap *, struct nilfs_bmap *);
/*
* Internal use only
*/
struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);
int nilfs_bmap_prepare_alloc_v(struct nilfs_bmap *,
union nilfs_bmap_ptr_req *);
void nilfs_bmap_commit_alloc_v(struct nilfs_bmap *,
Expand Down
84 changes: 84 additions & 0 deletions fs/nilfs2/btree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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,
Expand All @@ -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,
Expand Down
43 changes: 43 additions & 0 deletions fs/nilfs2/direct.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
#include "page.h"
#include "direct.h"
#include "alloc.h"
#include "dat.h"

static inline __le64 *nilfs_direct_dptrs(const struct nilfs_direct *direct)
{
Expand Down Expand Up @@ -62,6 +63,47 @@ static int nilfs_direct_lookup(const struct nilfs_bmap *bmap,
return 0;
}

static int nilfs_direct_lookup_contig(const struct nilfs_bmap *bmap,
__u64 key, __u64 *ptrp,
unsigned maxblocks)
{
struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
struct inode *dat = NULL;
__u64 ptr, ptr2;
sector_t blocknr;
int ret, cnt;

if (key > NILFS_DIRECT_KEY_MAX ||
(ptr = nilfs_direct_get_ptr(direct, key)) ==
NILFS_BMAP_INVALID_PTR)
return -ENOENT;

if (NILFS_BMAP_USE_VBN(bmap)) {
dat = nilfs_bmap_get_dat(bmap);
ret = nilfs_dat_translate(dat, ptr, &blocknr);
if (ret < 0)
return ret;
ptr = blocknr;
}

maxblocks = min_t(unsigned, maxblocks, NILFS_DIRECT_KEY_MAX - key + 1);
for (cnt = 1; cnt < maxblocks &&
(ptr2 = nilfs_direct_get_ptr(direct, key + cnt)) !=
NILFS_BMAP_INVALID_PTR;
cnt++) {
if (dat) {
ret = nilfs_dat_translate(dat, ptr2, &blocknr);
if (ret < 0)
return ret;
ptr2 = blocknr;
}
if (ptr2 != ptr + cnt)
break;
}
*ptrp = ptr;
return cnt;
}

static __u64
nilfs_direct_find_target_v(const struct nilfs_direct *direct, __u64 key)
{
Expand Down Expand Up @@ -367,6 +409,7 @@ static int nilfs_direct_assign(struct nilfs_bmap *bmap,

static const struct nilfs_bmap_operations nilfs_direct_ops = {
.bop_lookup = nilfs_direct_lookup,
.bop_lookup_contig = nilfs_direct_lookup_contig,
.bop_insert = nilfs_direct_insert,
.bop_delete = nilfs_direct_delete,
.bop_clear = NULL,
Expand Down
15 changes: 8 additions & 7 deletions fs/nilfs2/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -43,22 +43,23 @@
*
* This function does not issue actual read request of the specified data
* block. It is done by VFS.
* Bulk read for direct-io is not supported yet. (should be supported)
*/
int nilfs_get_block(struct inode *inode, sector_t blkoff,
struct buffer_head *bh_result, int create)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
unsigned long blknum = 0;
__u64 blknum = 0;
int err = 0, ret;
struct inode *dat = nilfs_dat_inode(NILFS_I_NILFS(inode));
unsigned maxblocks = bh_result->b_size >> inode->i_blkbits;

/* This exclusion control is a workaround; should be revised */
down_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
ret = nilfs_bmap_lookup(ii->i_bmap, (unsigned long)blkoff, &blknum);
up_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
if (ret == 0) { /* found */
down_read(&NILFS_MDT(dat)->mi_sem);
ret = nilfs_bmap_lookup_contig(ii->i_bmap, blkoff, &blknum, maxblocks);
up_read(&NILFS_MDT(dat)->mi_sem);
if (ret >= 0) { /* found */
map_bh(bh_result, inode->i_sb, blknum);
if (ret > 0)
bh_result->b_size = (ret << inode->i_blkbits);
goto out;
}
/* data block was not found */
Expand Down

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