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Commit d4b125e9 authored by Alex Elder's avatar Alex Elder
Browse files

rbd: increase maximum snapshot name length 



Change RBD_MAX_SNAP_NAME_LEN to be based on NAME_MAX.  That is a
practical limit for the length of a snapshot name (based on the
presence of a directory using the name under /sys/bus/rbd to
represent the snapshot).

The /sys entry is created by prefixing it with "snap_"; define that
prefix symbolically, and take its length into account in defining
the snapshot name length limit.

Enforce the limit in rbd_add_parse_args().  Also delete a dout()
call in that function that was not meant to be committed.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarDan Mick <dan.mick@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent db2388b6

drivers/block/rbd.c

+11 −5
Original line number Diff line number Diff line
@@ -61,7 +61,10 @@ 


#define RBD_MINORS_PER_MAJOR	256		/* max minors per blkdev */



#define RBD_MAX_SNAP_NAME_LEN	32

#define RBD_SNAP_DEV_NAME_PREFIX	"snap_"

#define RBD_MAX_SNAP_NAME_LEN	\

			(NAME_MAX - (sizeof (RBD_SNAP_DEV_NAME_PREFIX) - 1))



#define RBD_MAX_SNAP_COUNT	510	/* allows max snapc to fit in 4KB */

#define RBD_MAX_OPT_LEN		1024
@@ -2063,7 +2066,7 @@ static int rbd_register_snap_dev(struct rbd_snap *snap, 
	dev->type = &rbd_snap_device_type;

	dev->parent = parent;

	dev->release = rbd_snap_dev_release;

	dev_set_name(dev, "snap_%s", snap->name);

	dev_set_name(dev, "%s%s", RBD_SNAP_DEV_NAME_PREFIX, snap->name);

	dout("%s: registering device for snapshot %s\n", __func__, snap->name);



	ret = device_register(dev);
@@ -2797,8 +2800,13 @@ static char *rbd_add_parse_args(struct rbd_device *rbd_dev, 
	if (!rbd_dev->image_name)

		goto out_err;



	/* Snapshot name is optional */

	/* Snapshot name is optional; default is to use "head" */



	len = next_token(&buf);

	if (len > RBD_MAX_SNAP_NAME_LEN) {

		err_ptr = ERR_PTR(-ENAMETOOLONG);

		goto out_err;

	}

	if (!len) {

		buf = RBD_SNAP_HEAD_NAME; /* No snapshot supplied */

		len = sizeof (RBD_SNAP_HEAD_NAME) - 1;
@@ -2809,8 +2817,6 @@ static char *rbd_add_parse_args(struct rbd_device *rbd_dev, 
	memcpy(snap_name, buf, len);

	*(snap_name + len) = '\0';



dout("    SNAP_NAME is <%s>, len is %zd\n", snap_name, len);



	return snap_name;



out_err: