metadump: Introduce struct metadump_ops

We will need two sets of functions to implement two versions of metadump. This
commit adds the definition for 'struct metadump_ops' to hold pointers to
version specific metadump functions.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/db/metadump.c b/db/metadump.c
index 24f0b41fda..a2ec6ab569 100644
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -41,6 +41,30 @@ static const cmdinfo_t	metadump_cmd =
 		N_("[-a] [-e] [-g] [-m max_extent] [-w] [-o] filename"),
 		N_("dump metadata to a file"), metadump_help };
 
+struct metadump_ops {
+	/*
+	 * Initialize Metadump. This may perform actions such as
+	 * 1. Allocating memory for structures required for dumping the
+	 *    metadata.
+	 * 2. Writing a header to the beginning of the metadump file.
+	 */
+	int (*init)(void);
+	/*
+	 * Write metadata to the metadump file along with the required ancillary
+	 * data. @off and @len are in units of 512 byte blocks.
+	 */
+	int (*write)(enum typnm type, const char *data, xfs_daddr_t off,
+			int len);
+	/*
+	 * Flush any in-memory remanents of metadata to the metadump file.
+	 */
+	int (*finish_dump)(void);
+	/*
+	 * Free resources allocated during metadump process.
+	 */
+	void (*release)(void);
+};
+
 static struct metadump {
 	int			version;
 	bool			show_progress;
@@ -55,6 +79,7 @@ static struct metadump {
 	xfs_ino_t		cur_ino;
 	/* Metadump file */
 	FILE			*outf;
+	struct metadump_ops	*mdops;
 	/* header + index + buffers */
 	struct xfs_metablock	*metablock;
 	__be64			*block_index;