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nilfs2: add bmap function to seek a valid key

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Add a new bmap function, nilfs_bmap_seek_key(), which seeks a valid
entry and returns its key starting from a given key.  This function
can be used to skip hole blocks efficiently.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ryusuke Konishi 2015-04-16 12:46:36 -07:00 committed by Linus Torvalds
parent 3568a13f40
commit 5b20384fb3
4 changed files with 115 additions and 1 deletions
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31
fs/nilfs2/bmap.c
View File

@ -189,6 +189,37 @@ static int nilfs_bmap_do_delete(struct nilfs_bmap *bmap, __u64 key)
return bmap->b_ops->bop_delete(bmap, key);
}
/**
* nilfs_bmap_seek_key - seek a valid entry and return its key
* @bmap: bmap struct
* @start: start key number
* @keyp: place to store valid key
*
* Description: nilfs_bmap_seek_key() seeks a valid key on @bmap
* starting from @start, and stores it to @keyp if found.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*
* %-ENOENT - No valid entry was found
*/
int nilfs_bmap_seek_key(struct nilfs_bmap *bmap, __u64 start, __u64 *keyp)
{
int ret;
down_read(&bmap->b_sem);
ret = bmap->b_ops->bop_seek_key(bmap, start, keyp);
up_read(&bmap->b_sem);
if (ret < 0)
ret = nilfs_bmap_convert_error(bmap, __func__, ret);
return ret;
}
int nilfs_bmap_last_key(struct nilfs_bmap *bmap, __u64 *keyp)
{
int ret;

5
fs/nilfs2/bmap.h
View File

@ -76,8 +76,10 @@ struct nilfs_bmap_operations {
union nilfs_binfo *);
int (*bop_mark)(struct nilfs_bmap *, __u64, int);
/* The following functions are internal use only. */
int (*bop_seek_key)(const struct nilfs_bmap *, __u64, __u64 *);
int (*bop_last_key)(const struct nilfs_bmap *, __u64 *);
/* The following functions are internal use only. */
int (*bop_check_insert)(const struct nilfs_bmap *, __u64);
int (*bop_check_delete)(struct nilfs_bmap *, __u64);
int (*bop_gather_data)(struct nilfs_bmap *, __u64 *, __u64 *, int);
@ -155,6 +157,7 @@ void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
int nilfs_bmap_insert(struct nilfs_bmap *bmap, __u64 key, unsigned long rec);
int nilfs_bmap_delete(struct nilfs_bmap *bmap, __u64 key);
int nilfs_bmap_seek_key(struct nilfs_bmap *bmap, __u64 start, __u64 *keyp);
int nilfs_bmap_last_key(struct nilfs_bmap *bmap, __u64 *keyp);
int nilfs_bmap_truncate(struct nilfs_bmap *bmap, __u64 key);
void nilfs_bmap_clear(struct nilfs_bmap *);

63
fs/nilfs2/btree.c
View File

@ -633,6 +633,44 @@ static int nilfs_btree_do_lookup_last(const struct nilfs_bmap *btree,
return 0;
}
/**
* nilfs_btree_get_next_key - get next valid key from btree path array
* @btree: bmap struct of btree
* @path: array of nilfs_btree_path struct
* @minlevel: start level
* @nextkey: place to store the next valid key
*
* Return Value: If a next key was found, 0 is returned. Otherwise,
* -ENOENT is returned.
*/
static int nilfs_btree_get_next_key(const struct nilfs_bmap *btree,
const struct nilfs_btree_path *path,
int minlevel, __u64 *nextkey)
{
struct nilfs_btree_node *node;
int maxlevel = nilfs_btree_height(btree) - 1;
int index, next_adj, level;
/* Next index is already set to bp_index for leaf nodes. */
next_adj = 0;
for (level = minlevel; level <= maxlevel; level++) {
if (level == maxlevel)
node = nilfs_btree_get_root(btree);
else
node = nilfs_btree_get_nonroot_node(path, level);
index = path[level].bp_index + next_adj;
if (index < nilfs_btree_node_get_nchildren(node)) {
/* Next key is in this node */
*nextkey = nilfs_btree_node_get_key(node, index);
return 0;
}
/* For non-leaf nodes, next index is stored at bp_index + 1. */
next_adj = 1;
}
return -ENOENT;
}
static int nilfs_btree_lookup(const struct nilfs_bmap *btree,
__u64 key, int level, __u64 *ptrp)
{
@ -1563,6 +1601,27 @@ out:
return ret;
}
static int nilfs_btree_seek_key(const struct nilfs_bmap *btree, __u64 start,
__u64 *keyp)
{
struct nilfs_btree_path *path;
const int minlevel = NILFS_BTREE_LEVEL_NODE_MIN;
int ret;
path = nilfs_btree_alloc_path();
if (!path)
return -ENOMEM;
ret = nilfs_btree_do_lookup(btree, path, start, NULL, minlevel, 0);
if (!ret)
*keyp = start;
else if (ret == -ENOENT)
ret = nilfs_btree_get_next_key(btree, path, minlevel, keyp);
nilfs_btree_free_path(path);
return ret;
}
static int nilfs_btree_last_key(const struct nilfs_bmap *btree, __u64 *keyp)
{
struct nilfs_btree_path *path;
@ -2298,7 +2357,9 @@ static const struct nilfs_bmap_operations nilfs_btree_ops = {
.bop_assign = nilfs_btree_assign,
.bop_mark = nilfs_btree_mark,
.bop_seek_key = nilfs_btree_seek_key,
.bop_last_key = nilfs_btree_last_key,
.bop_check_insert = NULL,
.bop_check_delete = nilfs_btree_check_delete,
.bop_gather_data = nilfs_btree_gather_data,
@ -2318,7 +2379,9 @@ static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
.bop_assign = nilfs_btree_assign_gc,
.bop_mark = NULL,
.bop_seek_key = NULL,
.bop_last_key = NULL,
.bop_check_insert = NULL,
.bop_check_delete = NULL,
.bop_gather_data = NULL,

17
fs/nilfs2/direct.c
View File

@ -173,6 +173,21 @@ static int nilfs_direct_delete(struct nilfs_bmap *bmap, __u64 key)
return ret;
}
static int nilfs_direct_seek_key(const struct nilfs_bmap *direct, __u64 start,
__u64 *keyp)
{
__u64 key;
for (key = start; key <= NILFS_DIRECT_KEY_MAX; key++) {
if (nilfs_direct_get_ptr(direct, key) !=
NILFS_BMAP_INVALID_PTR) {
*keyp = key;
return 0;
}
}
return -ENOENT;
}
static int nilfs_direct_last_key(const struct nilfs_bmap *direct, __u64 *keyp)
{
__u64 key, lastkey;
@ -355,7 +370,9 @@ static const struct nilfs_bmap_operations nilfs_direct_ops = {
.bop_assign = nilfs_direct_assign,
.bop_mark = NULL,
.bop_seek_key = nilfs_direct_seek_key,
.bop_last_key = nilfs_direct_last_key,
.bop_check_insert = nilfs_direct_check_insert,
.bop_check_delete = NULL,
.bop_gather_data = nilfs_direct_gather_data,