- 01 Oct, 2012 40 commits
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Alex Elder authored
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>
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Alex Elder authored
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>
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Alex Elder authored
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>
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Alex Elder authored
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>
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Alex Elder authored
Create a function that encapsulates looking up the name, size and features related to a given snapshot, which is indicated by its index in an rbd device's snapshot context array of snapshot ids. This interface will be used to hide differences between the format 1 and format 2 images. At the moment this (looking up the name anyway) is slightly less efficient than what's done currently, but we may be able to optimize this a bit later on by cacheing the last lookup if it proves to be a problem. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Record the features values for each rbd image and each of its snapshots. This is really something that only becomes meaningful for version 2 images, so this is just putting in place code that will form common infrastructure. It may be useful to expand the sysfs entries--and therefore the information we maintain--for the image and for each snapshot. But I'm going to hold off doing that until we start making active use of the feature bits. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Pass the snapshot id and snapshot size rather than an index to __rbd_add_snap_dev() to specify values for a new snapshot. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Josh proposed the following change, and I don't think I could explain it any better than he did: From: Josh Durgin <josh.durgin@inktank.com> Date: Tue, 24 Jul 2012 14:22:11 -0700 To: ceph-devel <ceph-devel@vger.kernel.org> Message-ID: <500F1203.9050605@inktank.com> Right now the kernel still has one piece of rbd management duplicated from the rbd command line tool: snapshot creation. There's nothing special about snapshot creation that makes it advantageous to do from the kernel, so I'd like to remove the create_snap sysfs interface. That is, /sys/bus/rbd/devices/<id>/create_snap would be removed. Does anyone rely on the sysfs interface for creating rbd snapshots? If so, how hard would it be to replace with: rbd snap create pool/image@snap Is there any benefit to the sysfs interface that I'm missing? Josh This patch implements this proposal, removing the code that implements the "snap_create" sysfs interface for rbd images. As a result, quite a lot of other supporting code goes away. Suggested-by: Josh Durgin <josh.durgin@inktank.com> Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
New format 2 rbd images are permanently identified by a unique image id. Each rbd image also has a name, but the name can be changed. A format 2 rbd image will have an object--whose name is based on the image name--which maps an image's name to its image id. Create a new function rbd_dev_image_id() that checks for the existence of the image id object, and if it's found, records the image id in the rbd_device structure. Create a new rbd device attribute (/sys/bus/rbd/<num>/image_id) that makes this information available. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Define constant symbols related to the rbd format 2 object names. This begins to bring this version of the "rbd_types.h" header more in line with the current user-space version of that file. Complete reconciliation of differences will be done at some point later, as a separate task. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
An OSD object method call can be made using rbd_req_sync_exec(). Until now this has only been used for creating a new RBD snapshot, and that has only required sending data out, not receiving anything back from the OSD. We will now need to get data back from an OSD on a method call, so add parameters to rbd_req_sync_exec() that allow a buffer into which returned data should be placed to be specified, along with its size. Previously, rbd_req_sync_exec() passed a null pointer and zero size to rbd_req_sync_op(); change this so the new inbound buffer information is provided instead. Rename the "buf" and "len" parameters in rbd_req_sync_op() to make it more obvious they are describing inbound data. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
In order to allow both read requests and write requests to be initiated using rbd_req_sync_exec(), add an OSD flags value which can be passed down to rbd_req_sync_op(). Rename the "data" and "len" parameters to be more clear that they represent data that is outbound. At this point, this function is still only used (and only works) for write requests. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
We're ready to handle header object (refresh) events at the point we call rbd_bus_add_dev(). Set up the watch request on the rbd image header just after that, and after we've registered the devices for the snapshots for the initial snapshot context. Do this before announce the disk as available for use. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Move the setting of the initial capacity for an rbd image mapping into rb_init_disk(). Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
By the time rbd_dev_snaps_register() gets called during rbd device initialization, the main device will have already been registered. Similarly, a header refresh will only occur for an rbd device whose Linux device is registered. There is therefore no need to verify the main device is registered when registering a snapshot device. For the time being, turn the check into a WARN_ON(), but it can eventually just go away. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Call rbd_init_disk() from rbd_add() as soon as we have the major device number for the mapping. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Hold off setting the device id and formatting the device name in rbd_add() until just before it's needed. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Read the rbd header information and call rbd_dev_set_mapping() earlier--before registering the block device or setting up the sysfs entries for the image. The sysfs entries provide users access to some information that's only available after doing the rbd header initialization, so this will make sure it's valid right away. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
rbd_header_set_snap() is a simple initialization routine for an rbd device's mapping. It has to be called after the snapshot context for the rbd_dev has been updated, but can be done before snapshot devices have been registered. Change the name to rbd_dev_set_mapping() to better reflect its purpose, and call it a little sooner, before registering snapshot devices. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
When a new snapshot is found in an rbd device's updated snapshot context, __rbd_add_snap_dev() is called to create and insert an entry in the rbd devices list of snapshots. In addition, a Linux device is registered to represent the snapshot. For version 2 rbd images, it will be undesirable to initialize the device right away. So in anticipation of that, this patch separates the insertion of a snapshot entry in the snaps list from the creation of devices for those snapshots. To do this, create a new function rbd_dev_snaps_register() which traverses the list of snapshots and calls rbd_register_snap_dev() on any that have not yet been registered. Rename rbd_dev_snap_devs_update() to be rbd_dev_snaps_update() to better reflect that only the entry in the snaps list and not the snapshot's device is affected by the function. For now, call rbd_dev_snaps_register() immediately after each call to rbd_dev_snaps_update(). Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Move the assignment of the header name for an rbd image a bit later, outside rbd_add_parse_args() and into its caller. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
An rbd_dev structure maintains a list of current snapshots that have already been fully initialized. The entries on the list have type struct rbd_snap, and each entry contains a copy of information that's found in the rbd_dev's snapshot context and header. The only caller of snap_by_name() is rbd_header_set_snap(). In that call site any positive return value (the index in the snapshot array) is ignored, so there's no need to return the index in the snapshot context's id array when it's found. rbd_header_set_snap() also has only one caller--rbd_add()--and that call is made after a call to rbd_dev_snap_devs_update(). Because the rbd_snap structures are initialized in that function, the current snapshot list can be used instead of the snapshot context to look up a snapshot's information by name. Change snap_by_name() so it uses the snapshot list rather than the rbd_dev's snapshot context in looking up snapshot information. Return 0 if it's found rather than the snapshot id. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
When rbd_bus_add_dev() is called (one spot--in rbd_add()), the rbd image header has not even been read yet. This means that the list of snapshots will be empty at the time of the call. As a result, there is no need for the code that calls rbd_register_snap_dev() for each entry in that list--so get rid of it. Once the header has been read (just after returning), a call will be made to rbd_dev_snap_devs_update(), which will then find every snapshot in the context to be new and will therefore call rbd_register_snap_dev() via __rbd_add_snap_dev() accomplishing the same thing. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Move the calls to get the header semaphore out of rbd_header_set_snap() and into its caller. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
This just simplifies a few things in rbd_init_disk(), now that the previous patch has moved a bunch of initialization code out if it. Done separately to facilitate review. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Move some of the code that initializes an rbd header out of rbd_init_disk() and into its caller. Move the code at the end of rbd_init_disk() that sets the device capacity and activates the Linux device out of that function and into the caller, ensuring we still have the disk size available where we need it. Update rbd_free_disk() so it still aligns well as an inverse of rbd_init_disk(), moving the rbd_header_free() call out to its caller. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
There is only one caller of snap_by_name(), and it passes two values to be assigned, both of which are found within an rbd device structure. Change the interface so it just passes the address of the rbd_dev, and make the assignments to its fields directly. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
With the exception of the snapshot name, all of the mapping-specific fields in an rbd device structure are set in rbd_header_set_snap(). Pass the snapshot name to be assigned into rbd_header_set_snap() to keep all of the mapping assignments together. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
This is the first of two patches aimed at isolating the code that sets the mapping information into a single spot. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Add the size of the mapped image to the set of mapping-specific fields in an rbd_device, and use it when setting the capacity of the disk. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Several fields in a struct rbd_dev are related to what is mapped, as opposed to the actual base rbd image. If the base image is mapped these are almost unneeded, but if a snapshot is mapped they describe information about that snapshot. In some contexts this can be a little bit confusing. So group these mapping-related field into a structure to make it clear what they are describing. This also includes a minor change that rearranges the fields in the in-core image header structure so that invariant fields are at the top, followed by those that change. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
The "total_snaps" field in an rbd header structure is never any different from the value of "num_snaps" stored within a snapshot context. Avoid any confusion by just using the value held within the snapshot context, and get rid of the "total_snaps" field. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
A copy of rbd_dev->disk->queue is held in rbd_dev->q, but it's never actually used. So get just get rid of the field. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
The name __rbd_init_snaps_header() doesn't really convey what that function does very well. Its purpose is to scan a new snapshot context and either create or destroy snapshot device entries so that local host's view is consistent with the reality maintained on the OSDs. This patch just changes the name of this function, to be rbd_dev_snap_devs_update(). Still not perfect, but I think better. Also add some dynamic debug statements to this function. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
This should have been done as part of this commit: commit de71a297 Author: Alex Elder <elder@inktank.com> Date: Tue Jul 3 16:01:19 2012 -0500 rbd: rename rbd_device->id rbd_id_get() is assigning the rbd_dev->dev_id field. Change the name of that function as well as rbd_id_put() and rbd_id_max to reflect what they are affecting. Add some dynamic debug statements related to rbd device id activity. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
Define rbd_assert() and use it in place of various BUG_ON() calls now present in the code. By default assertion checking is enabled; we want to do this differently at some point. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
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Alex Elder authored
There are two places where rbd_get_segment() is called. One, in rbd_rq_fn(), only needs to know the length within a segment that an I/O request should be. The other, in rbd_do_op(), also needs the name of the object and the offset within it for the I/O request. Split out rbd_segment_name() into three dedicated functions: - rbd_segment_name() allocates and formats the name of the object for a segment containing a given rbd image offset - rbd_segment_offset() computes the offset within a segment for a given rbd image offset - rbd_segment_length() computes the length to use for I/O within a segment for a request, not to exceed the end of a segment object. In the new functions be a bit more careful, checking for possible error conditions: - watch for errors or overflows returned by snprintf() - catch (using BUG_ON()) potential overflow conditions when computing segment length Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
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Alex Elder authored
It is possible in rbd_get_num_segments() for an overflow to occur when adding the offset and length. This is easily avoided. Since the function returns an int and the one caller is already prepared to handle errors, have it return -ERANGE if overflow would occur. The overflow check would not work if a zero-length request was being tested, so short-circuit that case, returning 0 for the number of segments required. (This condition might be avoided elsewhere already, I don't know.) Have the caller end the request if either an error or 0 is returned. The returned value is passed to __blk_end_request_all(), meaning a 0 length request is not treated an error. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
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Alex Elder authored
There's a test for null rq pointer inside the while loop in rbd_rq_fn() that's not needed. That same test already occurred in the immediatly preceding loop condition test. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
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Alex Elder authored
In bio_chain_clone(), at the end of the function the bi_next field of the tail of the new bio chain is nulled. This isn't necessary, because if "tail" is non-null, its value will be the last bio structure allocated at the top of the while loop in that function. And before that structure is added to the end of the new chain, its bi_next pointer is always made null. While touching that function, clean a few other things: - define each local variable on its own line - move the definition of "tmp" to an inner scope - move the modification of gfpmask closer to where it's used - rearrange the logic that sets the chain's tail pointer Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
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