Commit Graph

89 Commits

Author SHA1 Message Date
Markus Armbruster
7c81e4e9db block: Don't bother asserting type of output visitor's output
After a visit of a complex QAPI type FOO

    ov = qobject_output_visitor_new(&foo);
    visit_type_FOO(ov, NULL, expr, &error_abort);
    visit_complete(ov, &foo);

we can safely assume qobject_type(foo) is QTYPE_QDICT.  We do in many
places, but occasionally assert qobject_type(obj) == QTYPE_QDICT.
Don't.  The appropriate place to check such fundamental properties of
QAPI visitors is the test suite.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1487363905-9480-15-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-02-22 19:52:20 +01:00
Paolo Bonzini
1919631e6b block: explicitly acquire aiocontext in bottom halves that need it
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-15-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-21 11:39:39 +00:00
Paolo Bonzini
9d45665448 block: explicitly acquire aiocontext in callbacks that need it
This covers both file descriptor callbacks and polling callbacks,
since they execute related code.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-14-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-21 11:39:36 +00:00
Peter Lieven
f67409a5bb block/nfs: fix naming of runtime opts
commit 94d6a7a accidentally left the naming of runtime opts and QAPI
scheme inconsistent. As one consequence passing of parameters in the
URI is broken. Sync the naming of the runtime opts to the QAPI
scheme.

Please note that this is technically backwards incompatible with the 2.8
release, but the 2.8 release is the only version that had the wrong naming.
Furthermore release 2.8 suffered from a NULL pointer dereference during
URI parsing.

Fixes: 94d6a7a76e
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Message-id: 1485942829-10756-3-git-send-email-pl@kamp.de
[mreitz: Fixed commit message]
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-02-12 00:47:42 +01:00
Peter Lieven
8d20abe87a block/nfs: fix NULL pointer dereference in URI parsing
parse_uint_full wants to put the parsed value into the
variable passed via its second argument which is NULL.

Fixes: 94d6a7a76e
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1485942829-10756-2-git-send-email-pl@kamp.de
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-02-12 00:47:42 +01:00
Stefan Hajnoczi
f6a51c84cd aio: add AioPollFn and io_poll() interface
The new AioPollFn io_poll() argument to aio_set_fd_handler() and
aio_set_event_handler() is used in the next patch.

Keep this code change separate due to the number of files it touches.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-01-03 16:38:48 +00:00
Prasanna Kumar Kalever
7103d9165b block/nfs: fix QMP to match debug option
The QMP definition of BlockdevOptionsNfs:
{ 'struct': 'BlockdevOptionsNfs',
  'data': { 'server': 'NFSServer',
            'path': 'str',
            '*user': 'int',
            '*group': 'int',
            '*tcp-syn-count': 'int',
            '*readahead-size': 'int',
            '*page-cache-size': 'int',
            '*debug-level': 'int' } }

To make this consistent with other block protocols like gluster, lets
change s/debug-level/debug/

Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-12-05 16:30:21 -05:00
Kevin Wolf
07555ba6f3 nfs: Fix memory leak in nfs_file_create()
The leak was introduced in commit 94d6a7a7.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-11-11 15:54:55 +01:00
Ashijeet Acharya
94d6a7a76e block/nfs: Introduce runtime_opts in NFS
Make NFS block driver use various fine grained runtime_opts.
Set .bdrv_parse_filename() to nfs_parse_filename() and introduce two
new functions nfs_parse_filename() and nfs_parse_uri() to help parsing
the URI.
Add a new option "server" which then accepts a new struct NFSServer.

Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
[ kwolf: Fixed client->path ]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-10-31 16:52:39 +01:00
Paolo Bonzini
c9d1a56174 block: only call aio_poll on the current thread's AioContext
aio_poll is not thread safe; for example bdrv_drain can hang if
the last in-flight I/O operation is completed in the I/O thread after
the main thread has checked bs->in_flight.

The bug remains latent as long as all of it is called within
aio_context_acquire/aio_context_release, but this will change soon.

To fix this, if bdrv_drain is called from outside the I/O thread,
signal the main AioContext through a dummy bottom half.  The event
loop then only runs in the I/O thread.

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477565348-5458-18-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
2016-10-28 21:50:18 +08:00
Paolo Bonzini
d746427aaf nfs: use BDRV_POLL_WHILE
This will make it possible to use nfs_get_allocated_file_size on
a file that is not in the main AioContext.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477565348-5458-10-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
2016-10-28 21:50:18 +08:00
Paolo Bonzini
aa92d6c460 nfs: move nfs_set_events out of the while loops
nfs_set_events only needs to be called once before entering the
while loop; afterwards, nfs_process_read and nfs_process_write
take care of it.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477565348-5458-9-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
2016-10-28 21:50:18 +08:00
Paolo Bonzini
fffb6e1223 block: use aio_bh_schedule_oneshot
This simplifies bottom half handlers by removing calls to qemu_bh_delete and
thus removing the need to stash the bottom half pointer in the opaque
datum.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-10-07 13:34:07 +02:00
Paolo Bonzini
0b8b8753e4 coroutine: move entry argument to qemu_coroutine_create
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: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-13 13:26:02 +02:00
Peter Lieven
d99b26c42a block/nfs: add support for libnfs pagecache
upcoming libnfs will have support for a read cache that can
significantly help to speed up requests since libnfs by design
circumvents the kernel cache.

Example:
 qemu -cdrom nfs://127.0.0.1/iso/my.iso?pagecache=1024

The pagecache parameters takes the maximum amount of pages to
cache.  A page in libnfs is always the NFS_BLKSIZE which is
4KB.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 1463662083-20814-3-git-send-email-pl@kamp.de
Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-06-28 22:52:45 -04:00
Peter Lieven
38f8d5e025 block/nfs: refuse readahead if cache.direct is on
if we open a NFS export with disabled cache we should refuse
the readahead feature as it will cache data inside libnfs.

If a export was opened with readahead enabled it should
futher not be allowed to disable the cache while running.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 1463662083-20814-2-git-send-email-pl@kamp.de
Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-06-28 22:52:45 -04:00
Stefan Hajnoczi
0d94b74655 block/nfs: add missing #include "qemu/cutils.h"
parse_uint_full() used to be included from qemu-common.h but was moved
to qemu/cutils.h in commit f348b6d1a5
("util: move declarations out of qemu-common.h").

Cc: Veronia Bahaa <veroniabahaa@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1459341994-20567-3-git-send-email-stefanha@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-03-30 16:50:39 -04:00
Stefan Hajnoczi
d165b8cb8b block/nfs: add missing #include "qapi/error.h"
error_setg() used to be included indirectly through qemu/osdep.h.  Since
commit da34e65cb4 ("include/qemu/osdep.h:
Don't include qapi/error.h") it requires an explicit include.

Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1459341994-20567-2-git-send-email-stefanha@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-03-30 16:50:39 -04:00
Peter Lieven
7725b8bf12 block/nfs: add support for setting debug level
recent libnfs versions support logging debug messages. Add
support for it in qemu through an URL parameter.

Example:
 qemu -cdrom nfs://127.0.0.1/iso/my.iso?debug=2

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1447052973-14513-1-git-send-email-pl@kamp.de
Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-02-29 14:54:30 -05:00
Peter Maydell
80c71a241a block: Clean up includes
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.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-01-20 13:36:23 +01:00
Fam Zheng
dca21ef23b aio: Add "is_external" flag for event handlers
All callers pass in false, and the real external ones will switch to
true in coming patches.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23 18:18:23 +02:00
Peter Lieven
18a8056e0b block/nfs: cache allocated filesize for read-only files
If the file is readonly its not expected to grow so
save the blocking call to nfs_fstat_async and use
the value saved at connection time. Also important
the monitor (and thus the main loop) will not hang
if block device info is queried and the NFS share
is unresponsive.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1440671441-7978-1-git-send-email-pl@kamp.de
Signed-off-by: Jeff Cody <jcody@redhat.com>
2015-09-25 08:37:07 -04:00
Peter Lieven
055c6f912c block/nfs: fix calculation of allocated file size
st.st_blocks is always counted in 512 byte units. Do not
use st.st_blksize as multiplicator which may be larger.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 1440067607-14547-1-git-send-email-pl@kamp.de
Signed-off-by: Jeff Cody <jcody@redhat.com>
2015-09-25 08:37:07 -04:00
Peter Lieven
29c838cdc9 block/nfs: limit maximum readahead size to 1MB
a malicious caller could otherwise specify a very
large value via the URI and force libnfs to allocate
a large amount of memory for the readahead buffer.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Message-id: 1435317241-25585-1-git-send-email-pl@kamp.de
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-07-02 10:06:23 +01:00
Max Reitz
fd752801ae block/nfs: Add create_opts
The nfs protocol driver is capable of creating images, but did not
specify any creation options. Fix it.

A way to test this issue is the following:

$ qemu-img create -f nfs nfs://127.0.0.1/foo.qcow2 64M

Without this patch, it segfaults. With this patch, it does not. However,
this is not something that should really work; qemu-img should check
whether the parameter for the -f option (and -O for convert) is indeed a
format, and error out if it is not. Therefore, I am not making it an
iotest.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:31:19 +01:00
Hu Tao
c2eb918e32 block: round up file size to nearest sector
Currently the file size requested by user is rounded down to nearest
sector, causing the actual file size could be a bit less than the size
user requested. Since some formats (like qcow2) record virtual disk
size in bytes, this can make the last few bytes cannot be accessed.

This patch fixes it by rounding up file size to nearest sector so that
the actual file size is no less than the requested file size.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-12 15:43:06 +02:00
Fam Zheng
810f4f86b7 nfs: Fix leak of opts in nfs_file_open
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-29 17:10:18 +01:00
Markus Armbruster
5839e53bbc block: Use g_new() & friends where that makes obvious sense
g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

Patch created with Coccinelle, with two manual changes on top:

* Add const to bdrv_iterate_format() to keep the types straight

* Convert the allocation in bdrv_drop_intermediate(), which Coccinelle
  inexplicably misses

Coccinelle semantic patch:

    @@
    type T;
    @@
    -g_malloc(sizeof(T))
    +g_new(T, 1)
    @@
    type T;
    @@
    -g_try_malloc(sizeof(T))
    +g_try_new(T, 1)
    @@
    type T;
    @@
    -g_malloc0(sizeof(T))
    +g_new0(T, 1)
    @@
    type T;
    @@
    -g_try_malloc0(sizeof(T))
    +g_try_new0(T, 1)
    @@
    type T;
    expression n;
    @@
    -g_malloc(sizeof(T) * (n))
    +g_new(T, n)
    @@
    type T;
    expression n;
    @@
    -g_try_malloc(sizeof(T) * (n))
    +g_try_new(T, n)
    @@
    type T;
    expression n;
    @@
    -g_malloc0(sizeof(T) * (n))
    +g_new0(T, n)
    @@
    type T;
    expression n;
    @@
    -g_try_malloc0(sizeof(T) * (n))
    +g_try_new0(T, n)
    @@
    type T;
    expression p, n;
    @@
    -g_realloc(p, sizeof(T) * (n))
    +g_renew(T, p, n)
    @@
    type T;
    expression p, n;
    @@
    -g_try_realloc(p, sizeof(T) * (n))
    +g_try_renew(T, p, n)

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-20 11:51:28 +02:00
Kevin Wolf
2347dd7b68 nfs: Handle failure for potentially large allocations
Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.

This patch addresses the allocations in the nfs block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15 15:07:15 +02:00
Peter Lieven
f42ca3cad1 block/nfs: add knob to set readahead
upcoming libnfs will feature internal readahead support.
Add a knob to pass the optional readahead value as a URL
parameter.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-26 13:51:01 +02:00
Peter Lieven
7c24384b3b block/nfs: fix url parameter checking
this patch fixes the incorrect usage of strncmp and
adds simple error checking by means of parse_uint_full
instead of atoi for the supplied URL parameters.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-26 13:51:01 +02:00
Chunyan Liu
c282e1fdf7 cleanup QEMUOptionParameter
Now that all backend drivers are using QemuOpts, remove all
QEMUOptionParameter related codes.

Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-16 17:23:21 +08:00
Chunyan Liu
98c10b810a nfs.c: replace QEMUOptionParameter with QemuOpts
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-16 17:23:20 +08:00
Peter Lieven
a2c0fe2fd2 block/nfs: fix potential segfault on early callback
it will happen in the future that the callback of a libnfs call
directly invokes the callback. In this case we end up in a segfault
because the NFSRPC is gone when we the BH is scheduled.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-16 17:23:19 +08:00
Stefan Hajnoczi
471799d135 nfs: implement .bdrv_detach/attach_aio_context()
Drop the assumption that we're using the main AioContext.  The following
functions need to be converted:
 * qemu_bh_new() -> aio_bh_new()
 * qemu_aio_set_fd_handler() -> aio_set_fd_handler()
 * qemu_aio_wait() -> aio_poll()

The .bdrv_detach/attach_aio_context() interfaces also need to be
implemented to move the fd handler from the old to the new AioContext.

Cc: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
2014-06-04 09:56:11 +02:00
Max Reitz
5f4d5e1aa6 block/nfs: Check for NULL server part
After the URL has been parsed make sure the server part is valid in
order to avoid a segmentation fault when calling nfs_mount().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-09 13:32:16 +02:00
Markus Armbruster
0fb6395c0c Use error_is_set() only when necessary (again)
error_is_set(&var) is the same as var != NULL, but it takes
whole-program analysis to figure that out.  Unnecessarily hard for
optimizers, static checkers, and human readers.  Commit 84d18f0 dumbed
it down to obvious, but a few more have crept in since, and
documentation was overlooked.  Dumb these down, too.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-25 18:05:06 +02:00
Peter Lieven
20fccb187c block/nfs: report errors from libnfs
if an NFS operation fails we should report what libnfs knows
about the failure. It is likely more than just an error code.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-03-19 09:39:41 +01:00
Peter Lieven
6542aa9c75 block: add native support for NFS
This patch adds native support for accessing images on NFS
shares without the requirement to actually mount the entire
NFS share on the host.

NFS Images can simply be specified by an url of the form:
nfs://<host>/<export>/<filename>[?param=value[&param2=value2[&...]]]

For example:
qemu-img create -f qcow2 nfs://10.0.0.1/qemu-images/test.qcow2

You need LibNFS from Ronnie Sahlberg available at:
   git://github.com/sahlberg/libnfs.git
for this to work.

During configure it is automatically probed for libnfs and support
is enabled on-the-fly. You can forbid or enforce libnfs support
with --disable-libnfs or --enable-libnfs respectively.

Due to NFS restrictions you might need to execute your binaries
as root, allow them to open priviledged ports (<1024) or specify
insecure option on the NFS server.

For additional information on ROOT vs. non-ROOT operation and URL
format + parameters see:
   https://raw.github.com/sahlberg/libnfs/master/README

Supported by qemu are the uid, gid and tcp-syncnt URL parameters.

LibNFS currently support NFS version 3 only.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-09 09:12:38 +01:00