This patch introduces the nilfs_palloc_scan_entries() function,
which takes an inode of one of nilfs' meta data files and iterates
through all of its entries. For each entry the callback function
pointer that is given as a parameter is called. The data parameter
is passed to the callback function, so that it may receive
parameters and return results.
Signed-off-by: Andreas Rohner <andreas.rohner@xxxxxxx>
---
fs/nilfs2/alloc.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nilfs2/alloc.h | 6 +++
2 files changed, 127 insertions(+)
diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index 741fd02..0edd85a 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -545,6 +545,127 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
}
/**
+ * nilfs_palloc_scan_entries - scan through every entry and execute dofunc
+ * @inode: inode of metadata file using this allocator
+ * @dofunc: function executed for every entry
+ * @data: data pointer passed to dofunc
+ *
+ * Description: nilfs_palloc_scan_entries() walks through every allocated entry
+ * of a metadata file and executes dofunc on it. It passes a data pointer to
+ * dofunc, which can be used as an input parameter or for returning of results.
+ *
+ * Return Value: On success, 0 is returned. On error, a
+ * negative error code is returned.
+ */
+int nilfs_palloc_scan_entries(struct inode *inode,
+ void (*dofunc)(struct inode *,
+ struct nilfs_palloc_req *,
+ void *),
+ void *data)
+{
+ struct buffer_head *desc_bh, *bitmap_bh;
+ struct nilfs_palloc_group_desc *desc;
+ struct nilfs_palloc_req req;
+ unsigned char *bitmap;
+ void *desc_kaddr, *bitmap_kaddr;
+ unsigned long group, maxgroup, ngroups;
+ unsigned long n, m, entries_per_group, groups_per_desc_block;
+ unsigned long i, j, pos;
+ unsigned long blkoff, prev_blkoff;
+ int ret;
+
+ ngroups = nilfs_palloc_groups_count(inode);
+ maxgroup = ngroups - 1;
+ entries_per_group = nilfs_palloc_entries_per_group(inode);
+ groups_per_desc_block = nilfs_palloc_groups_per_desc_block(inode);
+
+ for (group = 0; group < ngroups;) {
+ ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
+ if (ret == -ENOENT)
+ return 0;
+ else if (ret < 0)
+ return ret;
+ req.pr_desc_bh = desc_bh;
+ desc_kaddr = kmap(desc_bh->b_page);
+ desc = nilfs_palloc_block_get_group_desc(inode, group,
+ desc_bh, desc_kaddr);
+ n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
+ maxgroup);
+
+ for (i = 0; i < n; i++, desc++, group++) {
+ m = entries_per_group -
+ nilfs_palloc_group_desc_nfrees(inode,
+ group, desc);
+ if (!m)
+ continue;
+
+ ret = nilfs_palloc_get_bitmap_block(
+ inode, group, 0, &bitmap_bh);
+ if (ret == -ENOENT) {
+ ret = 0;
+ goto out_desc;
+ } else if (ret < 0)
+ goto out_desc;
+
+ req.pr_bitmap_bh = bitmap_bh;
+ bitmap_kaddr = kmap(bitmap_bh->b_page);
+ bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
+ /* entry blkoff is always bigger than 0 */
+ blkoff = 0;
+ pos = 0;
+
+ for (j = 0; j < m; ++j, ++pos) {
+ pos = nilfs_find_next_bit(bitmap,
+ entries_per_group, pos);
+
+ if (pos >= entries_per_group)
+ break;
+
+ /* found an entry */
+ req.pr_entry_nr =
+ entries_per_group * group + pos;
+
+ prev_blkoff = blkoff;
+ blkoff = nilfs_palloc_entry_blkoff(inode,
+ req.pr_entry_nr);
+
+ if (blkoff != prev_blkoff) {
+ if (prev_blkoff)
+ brelse(req.pr_entry_bh);
+
+ ret = nilfs_palloc_get_entry_block(
+ inode, req.pr_entry_nr,
+ 0, &req.pr_entry_bh);
+ if (ret < 0)
+ goto out_entry;
+ }
+
+ dofunc(inode, &req, data);
+ }
+
+ if (blkoff)
+ brelse(req.pr_entry_bh);
+ kunmap(bitmap_bh->b_page);
+ brelse(bitmap_bh);
+ }
+
+ kunmap(desc_bh->b_page);
+ brelse(desc_bh);
+ }
+
+ return 0;
+
+out_entry:
+ kunmap(bitmap_bh->b_page);
+ brelse(bitmap_bh);
+
+out_desc:
+ kunmap(desc_bh->b_page);
+ brelse(desc_bh);
+ return ret;
+}
+
+/**
* nilfs_palloc_commit_alloc_entry - finish allocation of a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the allocation
diff --git a/fs/nilfs2/alloc.h b/fs/nilfs2/alloc.h
index 4bd6451..0592035 100644
--- a/fs/nilfs2/alloc.h
+++ b/fs/nilfs2/alloc.h
@@ -77,6 +77,7 @@ int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
#define nilfs_set_bit_atomic ext2_set_bit_atomic
#define nilfs_clear_bit_atomic ext2_clear_bit_atomic
#define nilfs_find_next_zero_bit find_next_zero_bit_le
+#define nilfs_find_next_bit find_next_bit_le
/**
* struct nilfs_bh_assoc - block offset and buffer head association
@@ -106,5 +107,10 @@ void nilfs_palloc_setup_cache(struct inode *inode,
struct nilfs_palloc_cache *cache);
void nilfs_palloc_clear_cache(struct inode *inode);
void nilfs_palloc_destroy_cache(struct inode *inode);
+int nilfs_palloc_scan_entries(struct inode *,
+ void (*dofunc)(struct inode *,
+ struct nilfs_palloc_req *,
+ void *),
+ void *);
#endif /* _NILFS_ALLOC_H */
--
1.9.0
--
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