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.ryus...@lab.ntt.co.jp>
---
fs/nilfs2/bmap.c | 31 +++++++++++++++++++++++++
fs/nilfs2/bmap.h | 5 ++++-
fs/nilfs2/btree.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nilfs2/direct.c | 17 ++++++++++++++
4 files changed, 118 insertions(+), 1 deletion(-)
diff --git a/fs/nilfs2/bmap.c b/fs/nilfs2/bmap.c
index c82f436..27f75bc 100644
--- a/fs/nilfs2/bmap.c
+++ b/fs/nilfs2/bmap.c
@@ -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;
diff --git a/fs/nilfs2/bmap.h b/fs/nilfs2/bmap.h
index 9230d33..bfa817c 100644
--- a/fs/nilfs2/bmap.h
+++ b/fs/nilfs2/bmap.h
@@ -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 *);
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index ecdbae1..841d177 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -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 +1601,30 @@ 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;
+
+ if (start > NILFS_BTREE_KEY_MAX)
+ return -ENOENT;
+
+ 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 +2360,9 @@ 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 +2382,9 @@ 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,
diff --git a/fs/nilfs2/direct.c b/fs/nilfs2/direct.c
index 82f4865..ebf89fd 100644
--- a/fs/nilfs2/direct.c
+++ b/fs/nilfs2/direct.c
@@ -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,
--
1.8.3.1
--
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