4 files changed, 166 insertions, 23 deletions

diff --git a/xlators/features/qemu-block/src/bdrv-xlator.c b/xlators/features/qemu-block/src/bdrv-xlator.c
index 145f7c79d5e..106c5977535 100644
--- a/xlators/features/qemu-block/src/bdrv-xlator.c
+++ b/xlators/features/qemu-block/src/bdrv-xlator.c
@@ -69,10 +69,13 @@ static int
 qemu_gluster_open (BlockDriverState *bs, QDict *options, int bdrv_flags)
 {
 	inode_t *inode = NULL;
-	BDRVGlusterState *s = NULL;
+	BDRVGlusterState *s = bs->opaque;
 	QemuOpts *opts = NULL;
 	Error *local_err = NULL;
 	const char *filename = NULL;
+	char gfid_str[128];
+	int ret;
+	qb_conf_t *conf = THIS->private;
 
 	opts = qemu_opts_create_nofail(&runtime_opts);
 	qemu_opts_absorb_qdict(opts, options, &local_err);
@@ -84,12 +87,40 @@ qemu_gluster_open (BlockDriverState *bs, QDict *options, int bdrv_flags)
 
 	filename = qemu_opt_get(opts, "filename");
 
-	inode = qb_inode_from_filename (filename);
-	if (!inode)
-		return -EINVAL;
+	/*
+	 * gfid:<gfid> format means we're opening a backing image.
+	 */
+	ret = sscanf(filename, "gluster://gfid:%s", gfid_str);
+	if (ret) {
+		loc_t loc = {0,};
+		struct iatt buf = {0,};
+		uuid_t gfid;
 
-	s = bs->opaque;
-	s->inode = inode_ref (inode);
+		uuid_parse(gfid_str, gfid);
+
+		loc.inode = inode_find(conf->root_inode->table, gfid);
+		if (!loc.inode) {
+			loc.inode = inode_new(conf->root_inode->table);
+			uuid_copy(loc.inode->gfid, gfid);
+		}
+
+		uuid_copy(loc.gfid, loc.inode->gfid);
+		ret = syncop_lookup(FIRST_CHILD(THIS), &loc, NULL, &buf, NULL,
+				    NULL);
+		if (ret) {
+			loc_wipe(&loc);
+			return -errno;
+		}
+
+		s->inode = inode_ref(loc.inode);
+		loc_wipe(&loc);
+	} else {
+		inode = qb_inode_from_filename (filename);
+		if (!inode)
+			return -EINVAL;
+
+		s->inode = inode_ref(inode);
+	}
 
 	return 0;
 }
diff --git a/xlators/features/qemu-block/src/qb-coroutines.c b/xlators/features/qemu-block/src/qb-coroutines.c
index 9e64fecaf5c..d29117eb5d4 100644
--- a/xlators/features/qemu-block/src/qb-coroutines.c
+++ b/xlators/features/qemu-block/src/qb-coroutines.c
@@ -35,6 +35,8 @@ qb_format_and_resume (void *opaque)
 	call_stub_t *stub = NULL;
 	inode_t *inode = NULL;
 	char filename[64];
+	char base_filename[128];
+	int use_base = 0;
 	qb_inode_t *qb_inode = NULL;
 	Error *local_err = NULL;
 	fd_t *fd = NULL;
@@ -54,8 +56,62 @@ qb_format_and_resume (void *opaque)
 
 	qb_inode = qb_inode_ctx_get (frame->this, inode);
 
-	bdrv_img_create (filename, qb_inode->fmt, 0, 0,
-			 0, qb_inode->size, 0, &local_err, true);
+	/*
+	 * See if the caller specified a backing image.
+	 */
+	if (!uuid_is_null(qb_inode->backing_gfid) || qb_inode->backing_fname) {
+		loc_t loc = {0,};
+		char gfid_str[64];
+		struct iatt buf;
+
+		if (!uuid_is_null(qb_inode->backing_gfid)) {
+			loc.inode = inode_find(qb_conf->root_inode->table,
+					qb_inode->backing_gfid);
+			if (!loc.inode) {
+				loc.inode = inode_new(qb_conf->root_inode->table);
+				uuid_copy(loc.inode->gfid,
+					qb_inode->backing_gfid);
+			}
+			uuid_copy(loc.gfid, loc.inode->gfid);
+		} else if (qb_inode->backing_fname) {
+			loc.inode = inode_new(qb_conf->root_inode->table);
+			loc.name = qb_inode->backing_fname;
+			loc.parent = inode_parent(inode, NULL, NULL);
+			loc_path(&loc, loc.name);
+		}
+
+		/*
+		 * Lookup the backing image. Verify existence and/or get the
+		 * gfid if we don't already have it.
+		 */
+		ret = syncop_lookup(FIRST_CHILD(frame->this), &loc, NULL, &buf,
+				    NULL, NULL);
+		GF_FREE(qb_inode->backing_fname);
+		if (ret) {
+			loc_wipe(&loc);
+			ret = errno;
+			goto err;
+		}
+
+		uuid_copy(qb_inode->backing_gfid, buf.ia_gfid);
+		loc_wipe(&loc);
+
+		/*
+		 * We pass the filename of the backing image into the qemu block
+		 * subsystem as the associated gfid. This is embedded into the
+		 * clone image and passed along to the gluster bdrv backend when
+		 * the block subsystem needs to operate on the backing image on
+		 * behalf of the clone.
+		 */
+		uuid_unparse(qb_inode->backing_gfid, gfid_str);
+		snprintf(base_filename, sizeof(base_filename),
+			 "gluster://gfid:%s", gfid_str);
+		use_base = 1;
+	}
+
+	bdrv_img_create (filename, qb_inode->fmt,
+			 use_base ? base_filename : NULL, 0, 0, qb_inode->size,
+			 0, &local_err, true);
 
 	if (error_is_set (&local_err)) {
 		gf_log (frame->this->name, GF_LOG_ERROR, "%s",
@@ -113,6 +169,10 @@ qb_format_and_resume (void *opaque)
 	QB_STUB_UNWIND (stub, 0, 0);
 
 	return 0;
+
+err:
+	QB_STUB_UNWIND(stub, -1, ret);
+	return 0;
 }
 
 
diff --git a/xlators/features/qemu-block/src/qemu-block.c b/xlators/features/qemu-block/src/qemu-block.c
index 416ae44383c..0edb7b9493d 100644
--- a/xlators/features/qemu-block/src/qemu-block.c
+++ b/xlators/features/qemu-block/src/qemu-block.c
@@ -108,42 +108,76 @@ qb_iatt_fixup (xlator_t *this, inode_t *inode, struct iatt *iatt)
 int
 qb_format_extract (xlator_t *this, char *format, inode_t *inode)
 {
-	char       *s = NULL;
+	char       *s, *save;
 	uint64_t    size = 0;
 	char        fmt[QB_XATTR_VAL_MAX+1] = {0, };
 	qb_inode_t *qb_inode = NULL;
+	char *formatstr = NULL;
+	uuid_t gfid = {0,};
+	char gfid_str[64] = {0,};
+	int ret;
 
-	strncpy (fmt, format, QB_XATTR_VAL_MAX);
-	s = strchr (fmt, ':');
+	strncpy(fmt, format, QB_XATTR_VAL_MAX);
+
+	s = strtok_r(fmt, ":", &save);
 	if (!s)
 		goto invalid;
-	if (s == fmt)
-		goto invalid;
+	formatstr = gf_strdup(s);
 
-	*s = 0; s++;
-	if (!*s || strchr (s, ':'))
+	s = strtok_r(NULL, ":", &save);
+	if (!s)
 		goto invalid;
-
 	if (gf_string2bytesize (s, &size))
 		goto invalid;
-
 	if (!size)
 		goto invalid;
 
+	s = strtok_r(NULL, "\0", &save);
+	if (s && !strncmp(s, "<gfid:", strlen("<gfid:"))) {
+		/*
+		 * Check for valid gfid backing image specifier.
+		 */
+		if (strlen(s) + 1 > sizeof(gfid_str))
+			goto invalid;
+		ret = sscanf(s, "<gfid:%[^>]s", gfid_str);
+		if (ret == 1) {
+			ret = uuid_parse(gfid_str, gfid);
+			if (ret < 0)
+				goto invalid;
+		}
+	}
+
 	qb_inode = qb_inode_ctx_get (this, inode);
 	if (!qb_inode)
 		qb_inode = GF_CALLOC (1, sizeof (*qb_inode),
 				      gf_qb_mt_qb_inode_t);
-	if (!qb_inode)
+	if (!qb_inode) {
+		GF_FREE(formatstr);
 		return ENOMEM;
+	}
 
-	strncpy (qb_inode->fmt, fmt, QB_XATTR_VAL_MAX);
+	strncpy(qb_inode->fmt, formatstr, QB_XATTR_VAL_MAX);
 	qb_inode->size = size;
-	qb_inode->size_str = s;
+
+	/*
+	 * If a backing gfid was not specified, interpret any remaining bytes
+	 * associated with a backing image as a filename local to the parent
+	 * directory. The format processing will validate further.
+	 */
+	if (!uuid_is_null(gfid))
+		uuid_copy(qb_inode->backing_gfid, gfid);
+	else if (s)
+		qb_inode->backing_fname = gf_strdup(s);
 
 	inode_ctx_set (inode, this, (void *)&qb_inode);
+
+	GF_FREE(formatstr);
+
 	return 0;
+
 invalid:
+	GF_FREE(formatstr);
+
 	gf_log (this->name, GF_LOG_WARNING,
 		"invalid format '%s' in inode %s", format,
 		uuid_utoa (inode->gfid));
@@ -191,6 +225,15 @@ qb_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
 	if (op_ret == -1)
 		goto out;
 
+	/*
+	 * Cache the root inode for dealing with backing images. The format
+	 * coroutine and the gluster qemu backend driver both use the root inode
+	 * table to verify and/or redirect I/O to the backing image via
+	 * anonymous fd's.
+	 */
+	if (!conf->root_inode && __is_root_gfid(inode->gfid))
+		conf->root_inode = inode_ref(inode);
+
 	if (!xdata)
 		goto out;
 
@@ -249,6 +292,7 @@ qb_setxattr_format (call_frame_t *frame, xlator_t *this, call_stub_t *stub,
 	int op_errno = 0;
 	qb_local_t *qb_local = NULL;
 	data_t *data = NULL;
+	qb_inode_t *qb_inode;
 
 	if (!(data = dict_get (xattr, "trusted.glusterfs.block-format"))) {
 		QB_STUB_RESUME (stub);
@@ -264,12 +308,15 @@ qb_setxattr_format (call_frame_t *frame, xlator_t *this, call_stub_t *stub,
 		QB_STUB_UNWIND (stub, -1, op_errno);
 		return 0;
 	}
+	qb_inode = qb_inode_ctx_get(this, inode);
 
 	qb_local = frame->local;
 
 	qb_local->stub = stub;
 	qb_local->inode = inode_ref (inode);
-	strncpy (qb_local->fmt, format, QB_XATTR_VAL_MAX);
+
+	snprintf(qb_local->fmt, QB_XATTR_VAL_MAX, "%s:%lu", qb_inode->fmt,
+		 qb_inode->size);
 
 	qb_coroutine (frame, qb_format_and_resume);
 
@@ -1041,6 +1088,8 @@ fini (xlator_t *this)
 
         this->private = NULL;
 
+	if (conf->root_inode)
+		inode_unref(conf->root_inode);
         GF_FREE (conf);
 
 	return;
diff --git a/xlators/features/qemu-block/src/qemu-block.h b/xlators/features/qemu-block/src/qemu-block.h
index a91adb1ed51..55e7c23ac58 100644
--- a/xlators/features/qemu-block/src/qemu-block.h
+++ b/xlators/features/qemu-block/src/qemu-block.h
@@ -36,15 +36,16 @@
 
 #define QB_XATTR_KEY_MAX 64
 
-#define QB_XATTR_VAL_MAX 32
+#define QB_XATTR_VAL_MAX 64
 
 
 typedef struct qb_inode {
 	char fmt[QB_XATTR_VAL_MAX]; /* this is only the format, not "format:size" */
 	size_t size; /* virtual size in bytes */
-	char *size_str; /* pointer into fmt[] after ":" where size begins */
 	BlockDriverState *bs;
 	int refcnt;
+	uuid_t backing_gfid;
+	char *backing_fname;
 } qb_inode_t;
 
 
@@ -53,6 +54,7 @@ typedef struct qb_conf {
 	struct syncenv *env;
 	char qb_xattr_key[QB_XATTR_KEY_MAX];
 	char *default_password;
+	inode_t *root_inode;
 } qb_conf_t;
 
 
@@ -71,6 +73,7 @@ void qb_local_free (xlator_t *this, qb_local_t *local);
 int qb_coroutine (call_frame_t *frame, synctask_fn_t fn);
 inode_t *qb_inode_from_filename (const char *filename);
 int qb_inode_to_filename (inode_t *inode, char *filename, int size);
+int qb_format_extract (xlator_t *this, char *format, inode_t *inode);
 
 qb_inode_t *qb_inode_ctx_get (xlator_t *this, inode_t *inode);