ocfs2: Wrap virtual block reads in ocfs2_read_virt_blocks()
The ocfs2_read_dir_block() function really maps an inode's virtual
blocks to physical ones before calling ocfs2_read_blocks(). Let's
extract that to common code, because other places might want to do that.
Other than the block number being virtual, ocfs2_read_virt_blocks()
takes the same arguments as ocfs2_read_blocks(). It converts those
virtual block numbers to physical before calling ocfs2_read_blocks()
directly. If the blocks asked for are discontiguous, this can mean
multiple calls to ocfs2_read_blocks(), but this is mostly hidden from
the caller.
Like ocfs2_read_blocks(), the caller can pass in an existing
buffer_head. This is usually done to pick up some readahead I/O.
ocfs2_read_virt_blocks() checks the buffer_head's block number
against the extent map - it must match.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/extent_map.h b/fs/ocfs2/extent_map.h
index 1c4aa8b..b7dd973 100644
--- a/fs/ocfs2/extent_map.h
+++ b/fs/ocfs2/extent_map.h
@@ -57,4 +57,28 @@
u32 *p_cluster, u32 *num_clusters,
struct ocfs2_extent_list *el);
+int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
+ struct buffer_head *bhs[], int flags,
+ int (*validate)(struct super_block *sb,
+ struct buffer_head *bh));
+static inline int ocfs2_read_virt_block(struct inode *inode, u64 v_block,
+ struct buffer_head **bh,
+ int (*validate)(struct super_block *sb,
+ struct buffer_head *bh))
+{
+ int status = 0;
+
+ if (bh == NULL) {
+ printk("ocfs2: bh == NULL\n");
+ status = -EINVAL;
+ goto bail;
+ }
+
+ status = ocfs2_read_virt_blocks(inode, v_block, 1, bh, 0, validate);
+
+bail:
+ return status;
+}
+
+
#endif /* _EXTENT_MAP_H */