[ 155/171] rbd: add read_only rbd map option

Greg Kroah-Hartman
2013-01-15T23:21:09Z

From: Alex Elder <elder@inktank.com>

Add the ability to map an rbd image read-only, by specifying either
"read_only" or "ro" as an option on the rbd "command line." Also
allow the inverse to be explicitly specified using "read_write" or
"rw".

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
(based on commit cc0538b62c839c2df7b9f8378bb37e3b35faa608)
---
drivers/block/rbd.c | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)

--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -71,7 +71,8 @@
#define DEV_NAME_LEN 32
#define MAX_INT_FORMAT_WIDTH ((5 * sizeof (int)) / 2 + 1)

-#define RBD_NOTIFY_TIMEOUT_DEFAULT 10
+#define RBD_NOTIFY_TIMEOUT_DEFAULT 10
+#define RBD_READ_ONLY_DEFAULT false

/*
* block device image metadata (in-memory version)
@@ -95,6 +96,7 @@ struct rbd_image_header {

struct rbd_options {
int notify_timeout;
+ bool read_only;
};

/*
@@ -180,7 +182,7 @@ struct rbd_device {
u64 snap_id; /* current snapshot id */
/* whether the snap_id this device reads from still exists */
bool snap_exists;
- int read_only;
+ bool read_only;

struct list_head node;

@@ -346,12 +348,21 @@ enum {
/* int args above */
Opt_last_string,
/* string args above */
+ Opt_read_only,
+ Opt_read_write,
+ /* Boolean args above */
+ Opt_last_bool,
};

static match_table_t rbdopt_tokens = {
{Opt_notify_timeout, "notify_timeout=%d"},
/* int args above */
/* string args above */
+ {Opt_read_only, "read_only"},
+ {Opt_read_only, "ro"}, /* Alternate spelling */
+ {Opt_read_write, "read_write"},
+ {Opt_read_write, "rw"}, /* Alternate spelling */
+ /* Boolean args above */
{-1, NULL}
};

@@ -376,6 +387,8 @@ static int parse_rbd_opts_token(char *c,
} else if (token > Opt_last_int && token < Opt_last_string) {
dout("got string token %d val %s\n", token,
argstr[0].from);
+ } else if (token > Opt_last_string && token < Opt_last_bool) {
+ dout("got Boolean token %d\n", token);
} else {
dout("got token %d\n", token);
}
@@ -384,6 +397,12 @@ static int parse_rbd_opts_token(char *c,
case Opt_notify_timeout:
rbdopt->notify_timeout = intval;
break;
+ case Opt_read_only:
+ rbdopt->read_only = true;
+ break;
+ case Opt_read_write:
+ rbdopt->read_only = false;
+ break;
default:
BUG_ON(token);
}
@@ -407,6 +426,7 @@ static struct rbd_client *rbd_get_client
return ERR_PTR(-ENOMEM);

rbd_opts->notify_timeout = RBD_NOTIFY_TIMEOUT_DEFAULT;
+ rbd_opts->read_only = RBD_READ_ONLY_DEFAULT;

opt = ceph_parse_options(options, mon_addr,
mon_addr + mon_addr_len,
@@ -590,7 +610,7 @@ static int rbd_header_set_snap(struct rb
snapc->seq = 0;
dev->snap_id = CEPH_NOSNAP;
dev->snap_exists = false;
- dev->read_only = 0;
+ dev->read_only = dev->rbd_client->rbd_opts->read_only;
if (size)
*size = header->image_size;
} else {
@@ -599,7 +619,7 @@ static int rbd_header_set_snap(struct rb
goto done;
dev->snap_id = snapc->seq;
dev->snap_exists = true;
- dev->read_only = 1;
+ dev->read_only = true; /* No choice for snapshots */
}

ret = 0;