I promised Josh I would document whether there were any restrictions
needed for accessing fields of an rbd_spec structure. This adds a
big block of comments that documents the structure and how it is
used--including the fact that we don't attempt to synchronize access
to it.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: David Zafman <david.zafman@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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 <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Group the allocation and initialization of fields of the rbd device
structure created in rbd_add(). Move the grouped code down later in
the function, just prior to the call to rbd_dev_probe(). This is
for the most part simple code movement.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The only reason rbd_dev is passed to rbd_get_client() is so its
rbd_client field can get assigned. Instead, just return the
rbd_client pointer as a result and have the caller do the
assignment.
Change rbd_put_client() so it takes an rbd_client structure,
so follows the more typical symmetry with rbd_get_client().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Pass the address of an rbd_spec structure to rbd_add_parse_args().
Use it to hold the information defining the rbd image to be mapped
in an rbd_add() call.
Use the result in the caller to initialize the rbd_dev->id field.
This means rbd_dev is no longer needed in rbd_add_parse_args(),
so get rid of it.
Now that this transformation of rbd_add_parse_args() is complete,
correct and expand on the its header documentation to reflect the
new reality.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
With layered images we'll share rbd_spec structures, so add a
reference count to it. It neatens up some code also.
A silly get/put pair is added to the alloc routine just to avoid
"defined but not used" warnings. It will go away soon.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Group the fields that uniquely specify an rbd image into a new
reference-counted rbd_spec structure. This structure will be used
to describe the desired image when mapping an image, and when
probing parent images in layered rbd devices. Replace the set of
fields in the rbd device structure with a pointer to a dynamically
allocated rbd_spec.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Change the interface to rbd_add_parse_args() so it returns an
error code rather than a pointer. Return the ceph_options result
via a pointer whose address is passed as an argument.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Have the caller pass the address of an rbd_options structure to
rbd_add_parse_args(), to be initialized with the information
gleaned as a result of the parse.
I know, this is another near-reversal of a recent change...
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The snapshot name returned by rbd_add_parse_args() just gets saved
in the rbd_dev eventually. So just do that inside that function and
do away with the snap_name argument, both in rbd_add_parse_args()
and rbd_dev_set_mapping().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
They "options" argument to rbd_add_parse_args() (and it's partner
options_size) is now only needed within the function, so there's no
need to have the caller allocate and pass the options buffer. Just
allocate the options buffer within the function using dup_token().
Also distinguish between failures due to failed memory allocation
and failing because a required argument was missing.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The value returned in the "snap_name_len" argument to
rbd_add_parse_args() is never actually used, so get rid of it.
The snap_name_len recorded in rbd_dev_v2_snap_name() is not
useful either, so get rid of that too.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This patch makes rbd_add_parse_args() be the single place all
argument parsing occurs for an image map request:
- Move the ceph_parse_options() call into that function
- Use local variables rather than parameters to hold the list
of monitor addresses supplied
- Rather than returning it, pass the snapshot name (and its
length) back via parameters
- Have the function return a ceph_options structure pointer
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Move option parsing out of rbd_get_client() and into its caller.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
A Boolean field "snap_exists" in an rbd mapping is used to indicate
whether a mapped snapshot has been removed from an image's snapshot
context, to stop sending requests for that snapshot as soon as we
know it's gone.
Generalize the interpretation of this field so it applies to
non-snapshot (i.e. "head") mappings. That is, define its value
to be false until the mapping has been set, and then define it to be
true for both snapshot mappings or head mappings.
Rename the field "exists" to reflect the broader interpretation.
The rbd_mapping structure is on its way out, so move the field
back into the rbd_device structure.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Moving the snap_id and snap_name fields into the separate
rbd_mapping structure was misguided. (And in time, perhaps
we'll do away with that structure altogether...)
Move these fields back into struct rbd_device.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
If a format 2 image has a parent, its pool id will be specified
using a 64-bit value. Change the pool id we save for an image to
match that.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
If rbd_dev_snaps_update() has ever been called for an rbd device
structure there could be snapshot structures on its snaps list.
In rbd_add(), this function is called but a subsequent error
path neglected to clean up any of these snapshots.
Add a call to rbd_remove_all_snaps() in the appropriate spot to
remedy this. Change a couple of error labels to be a little
clearer while there.
Drop the leading underscores from the function name; there's nothing
special about that function that they might signify. As suggested
in review, the leading underscores in __rbd_remove_snap_dev() have
been removed as well.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When processing a request, rbd_rq_fn() makes clones of the bio's in
the request's bio chain and submits the results to osd's to be
satisfied. If a request bio straddles the boundary between objects
backing the rbd image, it must be represented by two cloned bio's,
one for the first part (at the end of one object) and one for the
second (at the beginning of the next object).
This has been handled by a function bio_chain_clone(), which
includes an interface only a mother could love, and which has
been found to have other problems.
This patch defines two new fairly generic bio functions (one which
replaces bio_chain_clone()) to help out the situation, and then
revises rbd_rq_fn() to make use of them.
First, bio_clone_range() clones a portion of a single bio, starting
at a given offset within the bio and including only as many bytes
as requested. As a convenience, a request to clone the entire bio
is passed directly to bio_clone().
Second, bio_chain_clone_range() performs a similar function,
producing a chain of cloned bio's covering a sub-range of the
source chain. No bio_pair structures are used, and if successful
the result will represent exactly the specified range.
Using bio_chain_clone_range() makes bio_rq_fn() a little easier
to understand, because it avoids the need to pass very much
state information between consecutive calls. By avoiding the need
to track a bio_pair structure, it also eliminates the problem
described here: http://tracker.newdream.net/issues/2933
Note that a block request (and therefore the complete length of
a bio chain processed in rbd_rq_fn()) is an unsigned int, while
the result of rbd_segment_length() is u64. This change makes
this range trunctation explicit, and trips a bug if the the
segment boundary is too far off.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The rbd_device structure has an embedded rbd_options structure.
Such a structure is needed to work with the generic ceph argument
parsing code, but there's no need to keep it around once argument
parsing is done.
Use a local variable to hold the rbd options used in parsing in
rbd_get_client(), and just transfer its content (it's just a
read_only flag) into the field in the rbd_mapping sub-structure
that requires that information.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
The aim of this patch is to make what's going on rbd_merge_bvec() a
bit more obvious than it was before. This was an issue when a
recent btrfs bug led us to question whether the merge function was
working correctly.
Use "obj" rather than "chunk" to indicate the units whose boundaries
we care about we call (rados) "objects".
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
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: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This adds a verification that an rbd image's object order is
within the upper and lower bounds supported by this implementation.
It must be at least 9 (SECTOR_SHIFT), because the Linux bio system
assumes that minimum granularity.
It also must be less than 32 (at the moment anyway) because there
exist spots in the code that store the size of a "segment" (object
backing an rbd image) in a signed int variable, which can be 32 bits
including the sign. We should be able to relax this limit once
we've verified the code uses 64-bit types where needed.
Note that the CLI tool already limits the order to the range 12-25.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The two calls to rbd_do_op() from rbd_rq_fn() differ only in the
value passed for the snapshot id and the snapshot context.
For reads the snapshot always comes from the mapping, and for writes
the snapshot id is always CEPH_NOSNAP.
The snapshot context is always null for reads. For writes, the
snapshot context always comes from the rbd header, but it is
acquired under protection of header semaphore and could change
thereafter, so we can't simply use what's available inside
rbd_do_op().
Eliminate the snapid parameter from rbd_do_op(), and set it
based on the I/O direction inside that function instead. Always
pass the snapshot context acquired in the caller, but reset it
to a null pointer inside rbd_do_op() if the operation is a read.
As a result, there is no difference in the read and write calls
to rbd_do_op() made in rbd_rq_fn(), so just call it unconditionally.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The only callers of rbd_do_op() are in rbd_rq_fn(), where call one
is used for writes and the other used for reads. The request passed
to rbd_do_op() already encodes the I/O direction, and that
information can be used inside the function to set the opcode and
flags value (rather than passing them in as arguments).
So get rid of the opcode and flags arguments to rbd_do_op().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Both rbd_req_read() and rbd_req_write() are simple wrapper routines
for rbd_do_op(), and each is only called once. Replace each wrapper
call with a direct call to rbd_do_op(), and get rid of the wrapper
functions.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The name of the "read-only" mapping option was inadvertently changed
in this commit:
f84344f3 rbd: separate mapping info in rbd_dev
Revert that hunk to return it to what it should be.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When rbd_dev_probe() calls rbd_dev_image_id() it expects to get
a 0 return code if successful, but it is getting a positive value.
The reason is that rbd_dev_image_id() returns the value it gets from
rbd_req_sync_exec(), which returns the number of bytes read in as a
result of the request. (This ultimately comes from
ceph_copy_from_page_vector() in rbd_req_sync_op()).
Force the return value to 0 when successful in rbd_dev_image_id().
Do the same in rbd_dev_v2_object_prefix().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
In rbd_dev_id_put(), there's a loop that's intended to determine
the maximum device id in use. But it isn't doing that at all,
the effect of how it's written is to simply use the just-put id
number, which ignores whole purpose of this function.
Fix the bug.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Now that v2 images support is fully implemented, have
rbd_dev_v2_probe() return 0 to indicate a successful probe.
(Note that an image that implements layering will fail
the probe early because of the feature chekc.)
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Version 2 images have two sets of feature bit fields. The first
indicates features possibly used by the image. The second indicates
features that the client *must* support in order to use the image.
When an image (or snapshot) is first examined, we need to make sure
that the local implementation supports the image's required
features. If not, fail the probe for the image.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a new function rbd_dev_v2_refresh() to update/refresh the
snapshot context for a format version 2 rbd image. This function
will update anything that is not fixed for the life of an rbd
image--at the moment this is mainly the snapshot context and (for
a base mapping) the size.
Update rbd_refresh_header() so it selects which function to use
based on the image format.
Rename __rbd_refresh_header() to be rbd_dev_v1_refresh()
to be consistent with the naming of its version 2 counterpart.
Similarly rename rbd_refresh_header() to be rbd_dev_refresh().
Unrelated--we use rbd_image_format_valid() here. Delete the other
use of it, which was primarily put in place to ensure that function
was referenced at the time it was defined.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Encapsulate the code that handles updating the size of a mapping
after an rbd image has been refreshed. This is done in anticipation
of the next patch, which will make this common code for format 1 and
2 images.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This shouldn't actually be possible because the layout struct is
constructed from the RBD header and validated then.
[elder@inktank.com: converted BUG() call to equivalent rbd_assert()]
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
There are three fields that are not yet updated for format 2 rbd
image headers: the version of the header object; the encryption
type; and the compression type. There is no interface defined for
fetching the latter two, so just initialize them explicitly to 0 for
now.
Change rbd_dev_v2_snap_context() so the caller can be supplied the
version for the header object.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define rbd_dev_v2_snap_name() to fetch the name for a particular
snapshot in a format 2 rbd image.
Define rbd_dev_v2_snap_info() to to be a wrapper for getting the
name, size, and features for a particular snapshot, using an
interface that matches the equivalent function for version 1 images.
Define rbd_dev_snap_info() wrapper function and use it to call the
appropriate function for getting the snapshot name, size, and
features, dependent on the rbd image format.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Fetch the snapshot context for an rbd format 2 image by calling
the "get_snapcontext" method on its header object.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The features values for an rbd format 2 image are fetched from the
server using a "get_features" method. The same method is used for
getting the features for a snapshot, so structure this addition with
a generic helper routine that can get this information for either.
The server will provide two 64-bit feature masks, one representing
the features potentially in use for this image (or its snapshot),
and one representing features that must be supported by the client
in order to work with the image.
For the time being, neither of these is really used so we keep
things simple and just record the first feature vector. Once we
start using these feature masks, what we record and what we expose
to the user will most likely change.
Signed-off-by: Alex Elder <elder@inktank.com>
The object prefix of an rbd format 2 image is fetched from the
server using a "get_object_prefix" method.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The size of an rbd format 2 image is fetched from the server using a
"get_size" method. The same method is used for getting the size of
a snapshot, so structure this addition with a generic helper routine
that we can get this information for either.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This defines a new function rbd_dev_probe() as a top-level
function for populating detailed information about an rbd device.
It first checks for the existence of a format 2 rbd image id object.
If it exists, the image is assumed to be a format 2 rbd image, and
another function rbd_dev_v2() is called to finish populating
header data for that image. If it does not exist, it is assumed to
be an old (format 1) rbd image, and calls a similar function
rbd_dev_v1() to populate its header information.
A new field, rbd_dev->format, is defined to record which version
of the rbd image format the device represents. For a valid mapped
rbd device it will have one of two values, 1 or 2.
So far, the format 2 images are not really supported; this is
laying out the infrastructure for fleshing out that support.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Alex Elder
Alex Elder
Sage Weil