--- /dev/null
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Wolfgang Bumiller <w.bumiller@proxmox.com>
+Date: Fri, 26 Apr 2019 09:15:28 +0200
+Subject: [PATCH] PVE: [Up+Config] file-posix: make locking optiono on create
+
+Otherwise creating images on nfs/cifs can be problematic.
+
+Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
+---
+ block/file-posix.c | 53 ++++++++++++++++++++++++++++++++++++----------------
+ qapi/block-core.json | 3 ++-
+ 2 files changed, 39 insertions(+), 17 deletions(-)
+
+diff --git a/block/file-posix.c b/block/file-posix.c
+index 431a9dddc6..be34698d04 100644
+--- a/block/file-posix.c
++++ b/block/file-posix.c
+@@ -2175,6 +2175,7 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
+ int fd;
+ uint64_t perm, shared;
+ int result = 0;
++ bool locked = false;
+
+ /* Validate options and set default values */
+ assert(options->driver == BLOCKDEV_DRIVER_FILE);
+@@ -2208,16 +2209,19 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
+ perm = BLK_PERM_WRITE | BLK_PERM_RESIZE;
+ shared = BLK_PERM_ALL & ~BLK_PERM_RESIZE;
+
+- /* Step one: Take locks */
+- result = raw_apply_lock_bytes(fd, perm, ~shared, false, errp);
+- if (result < 0) {
+- goto out_close;
+- }
++ if (file_opts->locking != ON_OFF_AUTO_OFF) {
++ /* Step one: Take locks */
++ result = raw_apply_lock_bytes(fd, perm, ~shared, false, errp);
++ if (result < 0) {
++ goto out_close;
++ }
++ locked = true;
+
+- /* Step two: Check that nobody else has taken conflicting locks */
+- result = raw_check_lock_bytes(fd, perm, shared, errp);
+- if (result < 0) {
+- goto out_unlock;
++ /* Step two: Check that nobody else has taken conflicting locks */
++ result = raw_check_lock_bytes(fd, perm, shared, errp);
++ if (result < 0) {
++ goto out_unlock;
++ }
+ }
+
+ /* Clear the file by truncating it to 0 */
+@@ -2250,13 +2254,15 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
+ }
+
+ out_unlock:
+- raw_apply_lock_bytes(fd, 0, 0, true, &local_err);
+- if (local_err) {
+- /* The above call should not fail, and if it does, that does
+- * not mean the whole creation operation has failed. So
+- * report it the user for their convenience, but do not report
+- * it to the caller. */
+- error_report_err(local_err);
++ if (locked) {
++ raw_apply_lock_bytes(fd, 0, 0, true, &local_err);
++ if (local_err) {
++ /* The above call should not fail, and if it does, that does
++ * not mean the whole creation operation has failed. So
++ * report it the user for their convenience, but do not report
++ * it to the caller. */
++ error_report_err(local_err);
++ }
+ }
+
+ out_close:
+@@ -2277,6 +2283,7 @@ static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
+ PreallocMode prealloc;
+ char *buf = NULL;
+ Error *local_err = NULL;
++ OnOffAuto locking;
+
+ /* Skip file: protocol prefix */
+ strstart(filename, "file:", &filename);
+@@ -2294,6 +2301,18 @@ static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
+ return -EINVAL;
+ }
+
++ locking = qapi_enum_parse(&OnOffAuto_lookup,
++ qemu_opt_get(opts, "locking"),
++ ON_OFF_AUTO_AUTO, &local_err);
++ if (local_err) {
++ error_propagate(errp, local_err);
++ return -EINVAL;
++ }
++
++ if (locking == ON_OFF_AUTO_AUTO) {
++ locking = ON_OFF_AUTO_OFF;
++ }
++
+ options = (BlockdevCreateOptions) {
+ .driver = BLOCKDEV_DRIVER_FILE,
+ .u.file = {
+@@ -2303,6 +2322,8 @@ static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
+ .preallocation = prealloc,
+ .has_nocow = true,
+ .nocow = nocow,
++ .has_locking = true,
++ .locking = locking,
+ },
+ };
+ return raw_co_create(&options, errp);
+diff --git a/qapi/block-core.json b/qapi/block-core.json
+index 9c3c2d4917..db859e20fa 100644
+--- a/qapi/block-core.json
++++ b/qapi/block-core.json
+@@ -3879,7 +3879,8 @@
+ 'data': { 'filename': 'str',
+ 'size': 'size',
+ '*preallocation': 'PreallocMode',
+- '*nocow': 'bool' } }
++ '*nocow': 'bool',
++ '*locking': 'OnOffAuto' } }
+
+ ##
+ # @BlockdevCreateOptionsGluster:
+--
+2.11.0
+