From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Wolfgang Bumiller <w.bumiller@proxmox.com>

Date: Mon, 6 Apr 2020 12:16:50 +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>

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

---

 block/file-posix.c   | 59 ++++++++++++++++++++++++++++++--------------

 qapi/block-core.json |  3 ++-

 2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c

index 3ac5177cbb..907aa3f22e 100644

--- a/block/file-posix.c

+++ b/block/file-posix.c

@@ -2443,6 +2443,7 @@ 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);

@@ -2483,19 +2484,22 @@ 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(NULL, 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(NULL, 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) {

-        error_append_hint(errp,

-                          "Is another process using the image [%s]?\n",

-                          file_opts->filename);

-        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) {

+            error_append_hint(errp,

+                              "Is another process using the image [%s]?\n",

+                              file_opts->filename);

+            goto out_unlock;

+        }

     }

     /* Clear the file by truncating it to 0 */

@@ -2549,13 +2553,15 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)

     }

 out_unlock:

-    raw_apply_lock_bytes(NULL, 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. */

-        warn_report_err(local_err);

+    if (locked) {

+        raw_apply_lock_bytes(NULL, 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. */

+            warn_report_err(local_err);

+        }

     }

 out_close:

@@ -2580,6 +2586,7 @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,

     PreallocMode prealloc;

     char *buf = NULL;

     Error *local_err = NULL;

+    OnOffAuto locking;

     /* Skip file: protocol prefix */

     strstart(filename, "file:", &filename);

@@ -2602,6 +2609,18 @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,

         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     = {

@@ -2613,6 +2632,8 @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,

             .nocow              = nocow,

             .has_extent_size_hint = has_extent_size_hint,

             .extent_size_hint   = extent_size_hint,

+            .has_locking        = true,

+            .locking            = locking,

         },

     };

     return raw_co_create(&options, errp);

diff --git a/qapi/block-core.json b/qapi/block-core.json

index 6356a63695..fdfa579d00 100644

--- a/qapi/block-core.json

+++ b/qapi/block-core.json

@@ -4341,7 +4341,8 @@

             'size':                 'size',

             '*preallocation':       'PreallocMode',

             '*nocow':               'bool',

-            '*extent-size-hint':    'size'} }

+            '*extent-size-hint':    'size',

+            '*locking':         'OnOffAuto' } }

 ##

 # @BlockdevCreateOptionsGluster: