linux-stable.git/drivers/block/rbd.c, branch linux-3.8.y

rbd: get rid of rbd_{get,put}_dev()

2012-12-20T16:56:44+00:00

The functions rbd_get_dev() and rbd_put_dev() are trivial wrappers
that add no value, and their existence suggests they may do more
than what they do.

Get rid of them.

Signed-off-by: Alex Elder 
Reviewed-by: Dan Mick

rbd: don't use ENOTSUPP

2012-12-17T18:07:32+00:00

ENOTSUPP is not a standard errno (it shows up as "Unknown error 524"
in an error message).  This is what was getting produced when the
the local rbd code does not implement features required by a
discovered rbd image.

Change the error code returned in this case to ENXIO.

Signed-off-by: Alex Elder 
Reviewed-by: Sage Weil

rbd: get rid of RBD_MAX_SEG_NAME_LEN

2012-12-17T14:37:29+00:00

RBD_MAX_SEG_NAME_LEN represents the maximum length of an rbd object
name (i.e., one of the objects providing storage backing an rbd
image).

Another symbol, MAX_OBJ_NAME_SIZE, is used in the osd client code to
define the maximum length of any object name in an osd request.

Right now they disagree, with RBD_MAX_SEG_NAME_LEN being too big.

There's no real benefit at this point to defining the rbd object
name length limit separate from any other object name, so just
get rid of RBD_MAX_SEG_NAME_LEN and use MAX_OBJ_NAME_SIZE in its
place.

Signed-off-by: Alex Elder 
Reviewed-by: Sage Weil

rbd: do not allow remove of mounted-on image

2012-12-17T14:36:59+00:00

There is no check in rbd_remove() to see if anybody holds open the
image being removed.  That's not cool.

Add a simple open count that goes up and down with opens and closes
(releases) of the device, and don't allow an rbd image to be removed
if the count is non-zero.

Protect the updates of the open count value with ctl_mutex to ensure
the underlying rbd device doesn't get removed while concurrently
being opened.

Signed-off-by: Alex Elder 
Reviewed-by: Sage Weil

rbd: get additional info in parent spec

2012-11-01T12:55:42+00:00

When a layered rbd image has a parent, that parent is identified
only by its pool id, image id, and snapshot id.  Images that have
been mapped also record *names* for those three id's.

Add code to look up these names for parent images so they match
mapped images more closely.  Skip doing this for an image if it
already has its pool name defined (this will be the case for images
mapped by the user).

It is possible that an the name of a parent image can't be
determined, even if the image id is valid.  If this occurs it
does not preclude correct operation, so don't treat this as
an error.

On the other hand, defined pools will always have both an id and a
name.   And any snapshot of an image identified as a parent for a
clone image will exist, and will have a name (if not it indicates
some other internal error).  So treat failure to get these bits
of information as errors.

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin

rbd: get parent spec for version 2 images

2012-11-01T12:55:42+00:00

Add support for getting the the information identifying the parent
image for rbd images that have them.  The child image holds a
reference to its parent image specification structure.  Create a new
entry "parent" in /sys/bus/rbd/image/N/ to report the identifying
information for the parent image, if any.

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin

rbd: allow null image name

2012-11-01T12:55:42+00:00

Format 2 parent images are partially identified by their image id,
but it may not be possible to determine their image name.  The name
is not strictly needed for correct operation, so we won't be
treating it as an error if we don't know it.  Handle this case
gracefully in rbd_name_show().

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin

rbd: allow null image name

2012-11-01T12:55:42+00:00

We will know the image id for format 2 parent images, but won't
initially know its image name.  Avoid making the query for an image
id in rbd_dev_image_id() if it's already known.

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin

rbd: encapsulate last part of probe

2012-11-01T12:55:42+00:00

Group the activities that now take place after an rbd_dev_probe()
call into a single function, and move the call to that function
into rbd_dev_probe() itself.

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin

rbd: define rbd_dev_{create,destroy}() helpers

2012-11-01T12:55:42+00:00

Encapsulate the creation/initialization and destruction of rbd
device structures.  The rbd_client and the rbd_spec structures
provided on creation hold references whose ownership is transferred
to the new rbd_device structure.

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin