[libvirt] [PATCH 3/6 v4] qemu: Record names of domain which uses the shared disk in hash table

[Daniel P. Berrange]

On Wed, Feb 20, 2013 at 03:43:55PM +0800, Osier Yang wrote:
> The hash entry is changed from "ref" to {ref, @domains}. With this, the
> caller can simply call qemuRemoveSharedDisk, without afraid of removing
> the entry belongs to other domains. qemuProcessStart will obviously
> benifit from it on error codepath (which calls qemuProcessStop to do
> the cleanup).
> ---
>  src/qemu/qemu_conf.c    |  169 +++++++++++++++++++++++++++++++++++++++++-----
>  src/qemu/qemu_conf.h    |   22 +++++-
>  src/qemu/qemu_driver.c  |    6 +-
>  src/qemu/qemu_process.c |    4 +-
>  4 files changed, 173 insertions(+), 28 deletions(-)
> 
> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> index e54227f..0bd6be0 100644
> --- a/src/qemu/qemu_conf.c
> +++ b/src/qemu/qemu_conf.c
> @@ -824,6 +824,11 @@ qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver,
>      qemuDriverUnlock(driver);
>  }
>  
> +struct _qemuSharedDiskEntry {
> +    size_t ref;
> +    char **domains; /* array of domain names */
> +};
> +
>  /* Construct the hash key for sharedDisks as "major:minor" */
>  char *
>  qemuGetSharedDiskKey(const char *disk_path)
> @@ -858,10 +863,9 @@ static int
>  qemuCheckSharedDisk(virHashTablePtr sharedDisks,
>                      virDomainDiskDefPtr disk)
>  {
> -    int val;
> -    size_t *ref = NULL;
>      char *sysfs_path = NULL;
>      char *key = NULL;
> +    int val;
>      int ret = 0;
>  
>      /* The only conflicts between shared disk we care about now
> @@ -881,7 +885,6 @@ qemuCheckSharedDisk(virHashTablePtr sharedDisks,
>      if (!virFileExists(sysfs_path))
>          goto cleanup;
>  
> -
>      if (!(key = qemuGetSharedDiskKey(disk->src))) {
>          ret = -1;
>          goto cleanup;
> @@ -890,7 +893,7 @@ qemuCheckSharedDisk(virHashTablePtr sharedDisks,
>      /* It can't be conflict if no other domain is
>       * is sharing it.
>       */
> -    if (!(ref = virHashLookup(sharedDisks, key)))
> +    if (!(virHashLookup(sharedDisks, key)))
>          goto cleanup;
>  
>      if (virGetDeviceUnprivSGIO(disk->src, NULL, &val) < 0) {
> @@ -916,14 +919,84 @@ cleanup:
>      return ret;
>  }
>  
> -/* Increase ref count if the entry already exists, otherwise
> - * add a new entry.
> +bool
> +qemuSharedDiskEntryDomainExists(qemuSharedDiskEntryPtr entry,
> +                                const char *name,
> +                                int *idx)
> +{
> +    size_t i;
> +
> +    for (i = 0; i < entry->ref; i++) {
> +        if (STREQ(entry->domains[i], name)) {
> +            if (idx)
> +                *idx = i;
> +            return true;
> +        }
> +    }
> +
> +    return false;
> +}
> +
> +void
> +qemuSharedDiskEntryFree(void *payload, const void *name ATTRIBUTE_UNUSED)
> +{
> +    qemuSharedDiskEntryPtr entry = (qemuSharedDiskEntryPtr)payload;

No need for that cast - void * casts to anything.

> +    size_t i;
> +
> +    for (i = 0; i < entry->ref; i++) {
> +        VIR_FREE(entry->domains[i]);
> +    }
> +    VIR_FREE(entry->domains);
> +    VIR_FREE(entry);
> +}

ACK if the cast is removed

Daniel
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