rbd: update capacity in rbd_dev_refresh()

When a mapped image changes size, we change the capacity recorded
for the Linux disk associated with it, in rbd_update_mapping_size().
That function is called in two places--the format 1 and format 2
refresh routines.

There is no need to set the capacity while holding the header
semaphore.  Instead, do it in the common rbd_dev_refresh(), using
the logic that's already there to initiate disk revalidation.

Add handling in the request function, just in case a request
that exceeds the capacity of the device comes in (perhaps one
that was started before a refresh shrunk the device).

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 15 insertions, 8 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 5d5e3f0b5fb4..9c094c67d778 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2874,6 +2874,13 @@ static void rbd_request_fn(struct request_queue *q)
                         goto end_request;       /* Shouldn't happen */
                 }
 
+                result = -EIO;
+                if (offset + length > rbd_dev->mapping.size) {
+                        rbd_warn(rbd_dev, "beyond EOD (%llu~%llu > %llu)\n",
+                                offset, length, rbd_dev->mapping.size);
+                        goto end_request;
+                }
+
                 result = -ENOMEM;
                 img_request = rbd_img_request_create(rbd_dev, offset, length,
                                                         write_request, false);
@@ -3116,14 +3123,8 @@ static void rbd_update_mapping_size(struct rbd_device *rbd_dev)
         if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
                 return;
 
-        if (rbd_dev->mapping.size != rbd_dev->header.image_size) {
-                sector_t size;
-
+        if (rbd_dev->mapping.size != rbd_dev->header.image_size)
                 rbd_dev->mapping.size = rbd_dev->header.image_size;
-                size = (sector_t)rbd_dev->mapping.size / SECTOR_SIZE;
-                dout("setting size to %llu sectors", (unsigned long long)size);
-                set_capacity(rbd_dev->disk, size);
-        }
 }
 
 /*
@@ -3200,8 +3201,14 @@ static int rbd_dev_refresh(struct rbd_device *rbd_dev)
 
         rbd_exists_validate(rbd_dev);
         mutex_unlock(&ctl_mutex);
-        if (mapping_size != rbd_dev->mapping.size)
+        if (mapping_size != rbd_dev->mapping.size) {
+                sector_t size;
+
+                size = (sector_t)rbd_dev->mapping.size / SECTOR_SIZE;
+                dout("setting size to %llu sectors", (unsigned long long)size);
+                set_capacity(rbd_dev->disk, size);
                 revalidate_disk(rbd_dev->disk);
+        }
 
         return ret;
 }