- 02 11月, 2016 10 次提交
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由 Eric Blake 提交于
Since we know that the maximum name we are willing to accept is small enough to stack-allocate, rework the iteration over NBD_OPT_LIST responses to reuse a stack buffer rather than allocating every time. Furthermore, we don't even have to allocate if we know the server's length doesn't match what we are searching for. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-12-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
The server has a nice helper function nbd_negotiate_drop_sync() which lets it easily ignore fluff from the client (such as the payload to an unknown option request). We can't quite make it common, since it depends on nbd_negotiate_read() which handles coroutine magic, but we can copy the idea into the client where we have places where we want to ignore data (such as the description tacked on the end of NBD_REP_SERVER). Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-11-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
The NBD spec says that a client should send NBD_OPT_ABORT rather than just dropping the connection, if the client doesn't like something the server sent during option negotiation. This is a best-effort attempt only, and can only be done in places where we know the server is still in sync with what we've sent, whether or not we've read everything the server has sent. Technically, the server then has to reply with NBD_REP_ACK, but it's not worth complicating the client to wait around for that reply. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-10-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
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: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-9-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
The NBD Protocol allows us to send human-readable messages along with any NBD_REP_ERR error during option negotiation; make use of this fact for clients that know what to do with our message. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-8-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
Rather than open-coding NBD_REP_SERVER, reuse the code we already have by adding a length parameter. Additionally, the refactoring will make adding NBD_OPT_GO in a later patch easier. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-7-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
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: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-6-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
We have both 'struct NBDRequest' and 'struct nbd_request'; making it confusing to see which does what. Furthermore, we want to rename nbd_request to align with our normal CamelCase naming conventions. So, rename the struct which is used to associate the data received during request callbacks, while leaving the shorter name for the description of the request sent over the wire in the NBD protocol. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-4-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
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: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-3-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
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: NEric Blake <eblake@redhat.com> Message-Id: <1476469998-28592-2-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 27 10月, 2016 1 次提交
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由 Daniel P. Berrange 提交于
Ensure that all I/O channels created for NBD are given names to distinguish their respective roles. Acked-by: NPaolo Bonzini <pbonzini@redhat.com> Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
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- 06 9月, 2016 1 次提交
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由 Kevin Wolf 提交于
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: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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- 04 8月, 2016 2 次提交
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由 Eric Blake 提交于
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: NEric Blake <eblake@redhat.com> Message-Id: <1469129688-22848-3-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
Commit ab7c548e added a check for invalid flags, but used an early return on error instead of properly going through the cleanup label. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1469129688-22848-2-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 20 7月, 2016 2 次提交
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由 Eric Blake 提交于
Change sector-based blk_discard(), blk_co_discard(), and blk_aio_discard() to instead be byte-based blk_pdiscard(), blk_co_pdiscard(), and blk_aio_pdiscard(). NBD gets a lot simpler now that ignoring the unaligned portion of a byte-based discard request is handled under the hood by the block layer. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Message-id: 1468624988-423-6-git-send-email-eblake@redhat.com Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
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由 Eric Blake 提交于
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: NEric Blake <eblake@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Acked-by: NPaolo Bonzini <pbonzini@redhat.com> Message-id: 1468607524-19021-6-git-send-email-eblake@redhat.com Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
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- 13 7月, 2016 1 次提交
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由 Paolo Bonzini 提交于
In practice the entry argument is always known at creation time, and it is confusing that sometimes qemu_coroutine_enter is used with a non-NULL argument to re-enter a coroutine (this happens in block/sheepdog.c and tests/test-coroutine.c). So pass the opaque value at creation time, for consistency with e.g. aio_bh_new. Mostly done with the following semantic patch: @ entry1 @ expression entry, arg, co; @@ - co = qemu_coroutine_create(entry); + co = qemu_coroutine_create(entry, arg); ... - qemu_coroutine_enter(co, arg); + qemu_coroutine_enter(co); @ entry2 @ expression entry, arg; identifier co; @@ - Coroutine *co = qemu_coroutine_create(entry); + Coroutine *co = qemu_coroutine_create(entry, arg); ... - qemu_coroutine_enter(co, arg); + qemu_coroutine_enter(co); @ entry3 @ expression entry, arg; @@ - qemu_coroutine_enter(qemu_coroutine_create(entry), arg); + qemu_coroutine_enter(qemu_coroutine_create(entry, arg)); @ reentry @ expression co; @@ - qemu_coroutine_enter(co, NULL); + qemu_coroutine_enter(co); except for the aforementioned few places where the semantic patch stumbled (as expected) and for test_co_queue, which would otherwise produce an uninitialized variable warning. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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- 17 6月, 2016 12 次提交
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由 Peter Maydell 提交于
The trace format string in nbd_send_request uses PRIu16 for request->type, but request->type is a uint32_t. This provokes compiler warnings on the OSX clang. Use PRIu32 instead. Signed-off-by: NPeter Maydell <peter.maydell@linaro.org> Message-id: 1466167331-17063-1-git-send-email-peter.maydell@linaro.org
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由 Eric Blake 提交于
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: NEric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-12-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
Add some debugging to flag servers that are not compliant to the NBD protocol. This would have flagged the server bug fixed in commit c0301fcc. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NAlex Bligh <alex@alex.org.uk> Message-Id: <1463006384-7734-11-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
The kernel ioctl() interface into NBD is limited to 'unsigned long'; we MUST pass in input with that type (and not int or size_t, as there may be platform ABIs where the wrong types promote incorrectly through var-args). Furthermore, on 32-bit platforms, the kernel is limited to a maximum export size of 2T (our BLKSIZE of 512 times a SIZE_BLOCKS constrained by 32 bit unsigned long). Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-8-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
NBD ioctl()s are used to manage an NBD client session where initial handshake is done in userspace, but then the transmission phase is handed off to the kernel through a /dev/nbdX device. As such, all ioctls sent to the kernel on the /dev/nbdX fd belong in client.c; nbd_disconnect() was out-of-place in server.c. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-7-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
The NBD protocol says that clients should not send a command flag that has not been negotiated (whether by the client requesting an option during a handshake, or because we advertise support for the flag in response to NBD_OPT_EXPORT_NAME), and that servers should reject invalid flags with EINVAL. We were silently ignoring the flags instead. The client can't rely on our behavior, since it is their fault for passing the bad flag in the first place, but it's better to be robust up front than to possibly behave differently than the client was expecting with the attempted flag. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NAlex Bligh <alex@alex.org.uk> Message-Id: <1463006384-7734-6-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
We have a few bugs in how we handle invalid client commands: - A client can send an NBD_CMD_DISC where from + len overflows, convincing us to reply with an error and stay connected, even though the protocol requires us to silently disconnect. Fix by hoisting the special case sooner. - A client can send an NBD_CMD_WRITE where from + len overflows, where we reply to the client with EINVAL without consuming the payload; this will normally cause us to fail if the next thing read is not the right magic, but in rare cases, could cause us to interpret the data payload as valid commands and do things not requested by the client. Fix by adding a complete flag to track whether we are in sync or must disconnect. Furthermore, we have split the checks for bogus from/len across two functions, when it is easier to do it all at once. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-5-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
We should never ignore failure from nbd_negotiate_send_rep(); if we are unable to write to the client, then it is not worth trying to continue the negotiation. Fortunately, the problem is not too severe - chances are that the errors being ignored here (mainly inability to write the reply to the client) are indications of a closed connection or something similar, which will also affect the next attempt to interact with the client and eventually reach a point where the errors are detected to end the loop. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-4-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
Clean up some debug message oddities missed earlier; this includes some typos, and recognizing that %d is not necessarily compatible with uint32_t. Also add a couple messages that I found useful while debugging things. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-3-git-send-email-eblake@redhat.com> [Do not use PRIx16, clang complains. - Paolo] Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
Rather than always flushing ourselves, let the block layer forward the FUA on to the underlying device - where all underlying layers also understand FUA, we are now more efficient; and where any underlying layer doesn't understand it, now the block layer takes care of the full flush fallback on our behalf. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-2-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Peter Maydell 提交于
The cpu_to_*w() functions just compose a pointer dereference with a byteswap. Instead use st*_p(), which handles potential pointer misalignment and avoids the need to cast the pointer. Signed-off-by: NPeter Maydell <peter.maydell@linaro.org> Message-Id: <1465575342-12146-1-git-send-email-peter.maydell@linaro.org> Reviewed-by: NEric Blake <eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Peter Maydell 提交于
The *_to_cpup() functions are not very useful, as they simply do a pointer dereference and then a *_to_cpu(). Instead use either: * ld*_*_p(), if the data is at an address that might not be correctly aligned for the load * a local dereference and *_to_cpu(), if the pointer is the correct type and known to be correctly aligned Signed-off-by: NPeter Maydell <peter.maydell@linaro.org> Message-Id: <1465570836-22211-1-git-send-email-peter.maydell@linaro.org> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 29 5月, 2016 1 次提交
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由 Eric Blake 提交于
Similar to commit df7b97ff, we are mishandling clients that give an unaligned NBD_CMD_TRIM request, and potentially trimming bytes that occur before their request; which in turn can cause potential unintended data loss (unlikely in practice, since most clients are sane and issue aligned trim requests). However, while we fixed read and write by switching to the byte interfaces of blk_, we don't yet have a byte interface for discard. On the other hand, trim is advisory, so rounding the user's request to simply ignore the first and last unaligned sectors (or the entire request, if it is sub-sector in length) is just fine. CC: qemu-stable@nongnu.org Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1464173965-9694-1-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 19 5月, 2016 1 次提交
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由 Paolo Bonzini 提交于
Move it to the actual users. There are still a few includes of qemu/bswap.h in headers; removing them is left for future work. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 18 5月, 2016 1 次提交
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由 Stefan Weil 提交于
Signed-off-by: NStefan Weil <sw@weilnetz.de> Reviewed-by: NPeter Maydell <peter.maydell@linaro.org> Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>
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- 12 5月, 2016 1 次提交
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由 Eric Blake 提交于
We have several block drivers that understand BDRV_REQ_FUA, and emulate it in the block layer for the rest by a full flush. But without a way to actually request BDRV_REQ_FUA during a pass-through blk_pwrite(), FUA-aware block drivers like NBD are forced to repeat the emulation logic of a full flush regardless of whether the backend they are writing to could do it more efficiently. This patch just wires up a flags argument; followup patches will actually make use of it in the NBD driver and in qemu-io. Signed-off-by: NEric Blake <eblake@redhat.com> Acked-by: NDenis V. Lunev <den@openvz.org> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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- 22 4月, 2016 1 次提交
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由 Eric Blake 提交于
The NBD protocol does not (yet) force any alignment constraints on clients. Even though qemu NBD clients always send requests that are aligned to 512 bytes, we must be prepared for non-qemu clients that don't care about alignment (even if it means they are less efficient). Our use of blk_read() and blk_write() was silently operating on the wrong file offsets when the client made an unaligned request, corrupting the client's data (but as the client already has control over the file we are serving, I don't think it is a security hole, per se, just a data corruption bug). Note that in the case of NBD_CMD_READ, an unaligned length could cause us to return up to 511 bytes of uninitialized trailing garbage from blk_try_blockalign() - hopefully nothing sensitive from the heap's prior usage is ever leaked in that manner. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Tested-by: NKevin Wolf <kwolf@redhat.com> Message-id: 1461249750-31928-1-git-send-email-eblake@redhat.com Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
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- 15 4月, 2016 2 次提交
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由 Eric Blake 提交于
Upstream NBD documents (as of commit 4feebc95) that servers MAY choose to operate in a conditional mode, where it is up to the client whether to use TLS. For qemu's case, we want to always be in FORCEDTLS mode, because of the risk of man-in-the-middle attacks, and since we never export more than one device; likewise, the qemu client will ALWAYS send NBD_OPT_STARTTLS as its first option. But now that SELECTIVETLS servers exist, it is feasible to encounter a (non-qemu) client that is programmed to talk to such a server, and does not do NBD_OPT_STARTTLS first, but rather wants to probe if it can use a non-encrypted export. The NBD protocol documents that we should let such a client continue trying, on the grounds that maybe the client will get the hint to send NBD_OPT_STARTTLS, rather than immediately dropping the connection. Note that NBD_OPT_EXPORT_NAME is a special case: since it is the only option request that can't have an error return, we have to (continue to) drop the connection on that one; rather, what we are fixing here is that all other replies prior to TLS initiation tell the client NBD_REP_ERR_TLS_REQD, but keep the connection alive. Signed-off-by: NEric Blake <eblake@redhat.com> Message-id: 1460671343-18485-1-git-send-email-eblake@redhat.com Signed-off-by: NMax Reitz <mreitz@redhat.com>
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由 Eric Blake 提交于
The NBD Protocol states that NBD_REP_SERVER may set 'length > sizeof(namelen) + namelen'; in which case the rest of the packet is a UTF-8 description of the export. While we don't know of any NBD servers that send this description yet, we had better consume the data so we don't choke when we start to talk to such a server. Also, a (buggy/malicious) server that replies with length < sizeof(namelen) would cause us to block waiting for bytes that the server is not sending, and one that replies with super-huge lengths could cause us to temporarily allocate up to 4G memory. Sanity check things before blindly reading incorrectly. Signed-off-by: NEric Blake <eblake@redhat.com> Message-id: 1460077777-31004-1-git-send-email-eblake@redhat.com Reviewed-by: NAlex Bligh <alex@alex.org.uk> Signed-off-by: NMax Reitz <mreitz@redhat.com>
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- 08 4月, 2016 4 次提交
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由 Paolo Bonzini 提交于
Until commit 1c778ef7 ("nbd: convert to using I/O channels for actual socket I/O", 2016-02-16), nbd_wr_sync returned -EAGAIN this scenario. nbd_reply_ready required these semantics because it has two conflicting requirements: 1) if a reply can be received on the socket, nbd_reply_ready needs to read the header outside coroutine context to identify _which_ coroutine to enter to process the rest of the reply 2) on the other hand, nbd_reply_ready can find a false positive if another thread (e.g. a VCPU thread running aio_poll) sneaks in and calls nbd_reply_ready too. In this case nbd_reply_ready does nothing and expects nbd_wr_syncv to return -EAGAIN. Currently, the solution to the first requirement is to wait in the very rare case of a read() that doesn't retrieve the reply header in its entirety; this is what nbd_wr_syncv does by calling qio_channel_wait(). However, the unconditional call to qio_channel_wait() breaks the second requirement. To fix this, the patch makes nbd_wr_syncv return -EAGAIN if done is zero, similar to the code before commit 1c778ef7. This is okay because NBD client-side negotiation is the only other case that calls nbd_wr_syncv outside a coroutine, and it places the socket in blocking mode. On the other hand, it is a bit unpleasant to put this in nbd_wr_syncv(), because the function is used by both client and server. The full fix would be to add a counter to NbdClientSession for how many bytes have been filled in s->reply. Then a reply can be filled by multiple separate invocations of nbd_reply_ready and the qio_channel_wait() call can be removed completely. Something to consider for 2.7... Reported-by: NChanglong Xie <xiecl.fnst@cn.fujitsu.com> Reviewed-by: NDaniel P. Berrange <berrange@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
nbd-server.c currently fails to handle unsupported options properly. If during option haggling the client sends an unknown request, the server kills the connection instead of letting the client try to fall back to something older. This is precisely what advertising NBD_FLAG_FIXED_NEWSTYLE was supposed to fix. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1459982918-32229-1-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Alex Bligh 提交于
nbd-client.c currently fails to handle unsupported options properly. If during option haggling the server finds an option that is unsupported, it returns an NBD_REP_ERR_UNSUP reply. According to nbd's proto.md, the format for such a reply should be: S: 64 bits, 0x3e889045565a9 (magic number for replies) S: 32 bits, the option as sent by the client to which this is a reply S: 32 bits, reply type (e.g., NBD_REP_ACK for successful completion, or NBD_REP_ERR_UNSUP to mark use of an option not known by this server S: 32 bits, length of the reply. This may be zero for some replies, in which case the next field is not sent S: any data as required by the reply (e.g., an export name in the case of NBD_REP_SERVER, or optional UTF-8 message for NBD_REP_ERR_*) However, in nbd-client.c, the reply type was being read, and if it contained an error, it was bailing out and issuing the next option request without first reading the length. This meant that the next option / handshake read had an extra 4 or more bytes of data in it. In practice, this makes Qemu incompatible with servers that do not support NBD_OPT_LIST. To verify this isn't an error in the specification or my reading of it, replies are sent by the reference implementation here: https://github.com/yoe/nbd/blob/66dfb35/nbd-server.c#L1232 and as is evident it always sends a 'datasize' (aka length) 32 bit word. Unsupported elements are replied to here: https://github.com/yoe/nbd/blob/66dfb35/nbd-server.c#L1371Signed-off-by: NAlex Bligh <alex@alex.org.uk> Message-Id: <1459882500-24316-1-git-send-email-alex@alex.org.uk> [rework to ALWAYS consume an optional UTF-8 message from the server] Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1459961962-18771-1-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Eric Blake 提交于
Print debug tracing messages while data is still in native ordering, rather than after we've potentially swapped it into network order for transmission. Also, it's nice if the server mentions what it is replying, to correlate it to with what the client says it is receiving. Signed-off-by: NEric Blake <eblake@redhat.com> Message-Id: <1459913704-19949-4-git-send-email-eblake@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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