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2016-11-02nbd: Implement NBD_CMD_WRITE_ZEROES on serverEric Blake
Upstream NBD protocol recently added the ability to efficiently write zeroes without having to send the zeroes over the wire, along with a flag to control whether the client wants to allow a hole. Note that when it comes to requiring full allocation, vs. permitting optimizations, the NBD spec intentionally picked a different sense for the flag; the rules in qemu are: MAY_UNMAP == 0: must write zeroes MAY_UNMAP == 1: may use holes if reads will see zeroes while in NBD, the rules are: FLAG_NO_HOLE == 1: must write zeroes FLAG_NO_HOLE == 0: may use holes if reads will see zeroes In all cases, the 'may use holes' scenario is optional (the server need not use a hole, and must not use a hole if subsequent reads would not see zeroes). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-16-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02nbd: Improve server handling of shutdown requestsEric Blake
NBD commit 6d34500b clarified how clients and servers are supposed to behave before closing a connection. It added NBD_REP_ERR_SHUTDOWN (for the server to announce it is about to go away during option haggling, so the client should quit sending NBD_OPT_* other than NBD_OPT_ABORT) and ESHUTDOWN (for the server to announce it is about to go away during transmission, so the client should quit sending NBD_CMD_* other than NBD_CMD_DISC). It also clarified that NBD_OPT_ABORT gets a reply, while NBD_CMD_DISC does not. This patch merely adds the missing reply to NBD_OPT_ABORT and teaches the client to recognize server errors. Actually teaching the server to send NBD_REP_ERR_SHUTDOWN or ESHUTDOWN would require knowing that the server has been requested to shut down soon (maybe we could do that by installing a SIGINT handler in qemu-nbd, which transitions from RUNNING to a new state that waits for the client to react, rather than just out-right quitting - but that's a bigger task for another day). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-15-git-send-email-eblake@redhat.com> [Move dummy ESHUTDOWN to include/qemu/osdep.h. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02nbd: Support shorter handshakeEric Blake
The NBD Protocol allows the server and client to mutually agree on a shorter handshake (omit the 124 bytes of reserved 0), via the server advertising NBD_FLAG_NO_ZEROES and the client acknowledging with NBD_FLAG_C_NO_ZEROES (only possible in newstyle, whether or not it is fixed newstyle). It doesn't shave much off the wire, but we might as well implement it. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alex Bligh <alex@alex.org.uk> Message-Id: <1476469998-28592-13-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02nbd: Share common option-sending code in clientEric Blake
Rather than open-coding each option request, it's easier to have common helper functions do the work. That in turn requires having convenient packed types for handling option requests and replies. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-9-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02nbd: Rename struct nbd_request and nbd_replyEric Blake
Our coding convention prefers CamelCase names, and we already have other existing structs with NBDFoo naming. Let's be consistent, before later patches add even more structs. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-6-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02nbd: Treat flags vs. command type as separate fieldsEric Blake
Current upstream NBD documents that requests have a 16-bit flags, followed by a 16-bit type integer; although older versions mentioned only a 32-bit field with masking to find flags. Since the protocol is in network order (big-endian over the wire), the ABI is unchanged; but dealing with the flags as a separate field rather than masking will make it easier to add support for upcoming NBD extensions that increase the number of both flags and commands. Improve some comments in nbd.h based on the current upstream NBD protocol (https://github.com/yoe/nbd/blob/master/doc/proto.md), and touch some nearby code to keep checkpatch.pl happy. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-3-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02nbd: Add qemu-nbd -D for human-readable descriptionEric Blake
The NBD protocol allows servers to advertise a human-readable description alongside an export name during NBD_OPT_LIST. Add an option to pass through the user's string to the NBD client. Doing this also makes it easier to test commit 200650d4, which is the client counterpart of receiving the description. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-2-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-05nbd-server: Use a separate BlockBackendKevin Wolf
The builtin NBD server uses its own BlockBackend now instead of reusing the monitor/guest device one. This means that it has its own writethrough setting now. The builtin NBD server always uses writeback caching now regardless of whether the guest device has WCE enabled. qemu-nbd respects the cache mode given on the command line. We still need to keep a reference to the monitor BB because we put an eject notifier on it, but we don't use it for any I/O. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-08-03nbd: Limit nbdflags to 16 bitsEric Blake
Rather than asserting that nbdflags is within range, just give it the correct type to begin with :) nbdflags corresponds to the per-export portion of NBD Protocol "transmission flags", which is 16 bits in response to NBD_OPT_EXPORT_NAME and NBD_OPT_GO. Furthermore, upstream NBD has never passed the global flags to the kernel via ioctl(NBD_SET_FLAGS) (the ioctl was first introduced in NBD 2.9.22; then a latent bug in NBD 3.1 actually tried to OR the global flags with the transmission flags, with the disaster that the addition of NBD_FLAG_NO_ZEROES in 3.9 caused all earlier NBD 3.x clients to treat every export as read-only; NBD 3.10 and later intentionally clip things to 16 bits to pass only transmission flags). Qemu should follow suit, since the current two global flags (NBD_FLAG_FIXED_NEWSTYLE and NBD_FLAG_NO_ZEROES) have no impact on the kernel's behavior during transmission. CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1469129688-22848-3-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-20nbd: Convert to byte-based interfaceEric Blake
The NBD protocol doesn't have any notion of sectors, so it is a fairly easy conversion to use byte-based read and write. Signed-off-by: Eric Blake <eblake@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1468624988-423-19-git-send-email-eblake@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-20nbd: Drop unused offset parameterEric Blake
Now that NBD relies on the block layer to fragment things, we no longer need to track an offset argument for which fragment of a request we are actually servicing. While at it, use true and false instead of 0 and 1 for a bool parameter. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1468607524-19021-6-git-send-email-eblake@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05nbd: Allow larger requestsEric Blake
The NBD layer was breaking up request at a limit of 2040 sectors (just under 1M) to cater to old qemu-nbd. But the server limit was raised to 32M in commit 2d8214885 to match the kernel, more than three years ago; and the upstream NBD Protocol is proposing documentation that without any explicit communication to state otherwise, a client should be able to safely assume that a 32M transaction will work. It is time to rely on the larger sizing, and any downstream distro that cares about maximum interoperability to older qemu-nbd servers can just tweak the value of #define NBD_MAX_SECTORS. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: qemu-stable@nongnu.org Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-06-16nbd: Avoid magic number for NBD max name sizeEric Blake
Declare a constant and use that when determining if an export name fits within the constraints we are willing to support. Note that upstream NBD recently documented that clients MUST support export names of 256 bytes (not including trailing NUL), and SHOULD support names up to 4096 bytes. 4096 is a bit big (we would lose benefits of stack-allocation of a name array), and we already have other limits in place (for example, qcow2 snapshot names are clamped around 1024). So for now, just stick to the required minimum, as that's easier to audit than a full-scale support for larger names. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-12-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16nbd: simplify the nbd_request and nbd_reply structsPaolo Bonzini
These structs are never used to represent the bytes that go over the network. The big-endian network data is built into a uint8_t array in nbd_{receive,send}_{request,reply}. Remove the unused magic field, reorder the struct to avoid holes, and remove the packed attribute. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-23include: Clean up includesPeter Maydell
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. NB: If this commit breaks compilation for your out-of-tree patchseries or fork, then you need to make sure you add #include "qemu/osdep.h" to any new .c files that you have. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com>
2016-02-16nbd: implement TLS support in the protocol negotiationDaniel P. Berrange
This extends the NBD protocol handling code so that it is capable of negotiating TLS support during the connection setup. This involves requesting the STARTTLS protocol option before any other NBD options. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1455129674-17255-14-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16nbd: convert to using I/O channels for actual socket I/ODaniel P. Berrange
Now that all callers are converted to use I/O channels for initial connection setup, it is possible to switch the core NBD protocol handling core over to use QIOChannel APIs for actual sockets I/O. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1455129674-17255-7-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-15nbd: Always call "close_fn" in nbd_client_newFam Zheng
Rename the parameter "close" to "close_fn" to disambiguous with close(2). This unifies error handling paths of NBDClient allocation: nbd_client_new will shutdown the socket and call the "close_fn" callback if negotiation failed, so the caller don't need a different path than the normal close. The returned pointer is never used, make it void in preparation for the next patch. Signed-off-by: Fam Zheng <famz@redhat.com> Message-Id: <1452760863-25350-2-git-send-email-famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-18nbd: Set block size to BDRV_SECTOR_SIZEMax Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <1424887718-10800-13-git-send-email-mreitz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-18nbd: Fix potential signed overflow issuesMax Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <1424887718-10800-11-git-send-email-mreitz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-18nbd: Handle blk_getlength() failureMax Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <1424887718-10800-9-git-send-email-mreitz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-16nbd: Drop BDS backpointerMax Reitz
Before this patch, the "opaque" pointer in an NBD BDS points to a BDRVNBDState, which contains an NbdClientSession object, which in turn contains a pointer to the BDS. This pointer may become invalid due to bdrv_swap(), so drop it, and instead pass the BDS directly to the nbd-client.c functions which then retrieve the NbdClientSession object from there. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1423256778-3340-2-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-02-06nbd: Improve error messagesMax Reitz
This patch makes use of the Error object for nbd_receive_negotiate() so that errors during negotiation look nicer. Furthermore, this patch adds an additional error message if the received magic was wrong, but would be correct for the other protocol version, respectively: So if an export name was specified, but the NBD server magic corresponds to an old handshake, this condition is explicitly signaled to the user, and vice versa. As these messages are now part of the "Could not open image" error message, additional filtering has to be employed in iotest 083, which this patch does as well. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10nbd: Change external interface to BlockBackendMax Reitz
Substitute BlockDriverState by BlockBackend in every globally visible function provided by nbd. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1416309679-333-5-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-30nbd: Handle NBD_OPT_LIST option.Hani Benhabiles
Signed-off-by: Hani Benhabiles <kroosec@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-06-30nbd: Handle fixed new-style clients.Hani Benhabiles
When this flag is set, the server tells the client that it can send another option if the server received a request with an option that it doesn't understand instead of directly closing the connection. Also add link to the most up-to-date documentation. Signed-off-by: Hani Benhabiles <kroosec@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-02-21nbd: move socket wrappers to qemu-nbdPaolo Bonzini
qemu-nbd is one of the few valid users of qerror_report_err. Move the error-reporting socket wrappers there. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21nbd: inline tcp_socket_incoming_spec into sole callerPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21nbd: correctly propagate errorsPaolo Bonzini
Before: $ ./qemu-io-old qemu-io-old> open -r -o file.driver=nbd one of path and host must be specified. qemu-io-old: can't open device (null): Could not open image: Invalid argument $ ./qemu-io-old qemu-io-old> open -r -o file.driver=nbd,file.host=foo,file.path=bar path and host may not be used at the same time. qemu-io-old: can't open device (null): Could not open image: Invalid argument After: $ ./qemu-io qemu-io> open -r -o file.driver=nbd qemu-io: can't open device (null): one of path and host must be specified. $ ./qemu-io qemu-io> open -r -o file.driver=nbd,file.host=foo,file.path=bar qemu-io: can't open device (null): path and host may not be used at the same time. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-05-03nbd: support large NBD requestsStefan Hajnoczi
The Linux nbd driver recently increased the maximum supported request size up to 32 MB: commit 078be02b80359a541928c899c2631f39628f56df Author: Michal Belczyk <belczyk@bsd.krakow.pl> Date: Tue Apr 30 15:28:28 2013 -0700 nbd: increase default and max request sizes Raise the default max request size for nbd to 128KB (from 127KB) to get it 4KB aligned. This patch also allows the max request size to be increased (via /sys/block/nbd<x>/queue/max_sectors_kb) to 32MB. QEMU's 1 MB buffers are too small to handle these requests. This patch allocates data buffers dynamically and allows up to 32 MB per request. Reported-by: Nick Thomas <nick@bytemark.co.uk> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-22nbd: Remove unused functionsKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2013-03-22nbd: Keep hostname and port separateKevin Wolf
The NBD block supports an URL syntax, for which a URL parser returns separate hostname and port fields. It also supports the traditional qemu syntax encoded in a filename. Until now, after parsing the URL to get each piece of information, a new string is built to be fed to socket functions. Instead of building a string in the URL case that is immediately parsed again, parse the string in both cases and use the QemuOpts interface to qemu-sockets.c. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2012-12-19block: move include files to include/block/Paolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>