[libvirt] [PATCH] scsi: Adjust return status from getBlockDevice
Michal Privoznik
mprivozn at redhat.com
Mon Jun 15 11:17:26 UTC 2015
On 12.06.2015 13:22, John Ferlan wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1224233
>
> Currently it's not possible to determine the difference between a
> fatal memory allocation or failure to open/read the directory error
> with a perhaps less fatal, I didn't find the "block" device in the
> directory (which may be a disk entry without a block device).
>
> In the case of the latter, we shouldn't cause failure to continue
> searching in the caller (virStorageBackendSCSIFindLUs), rather we
> should allow trying reading the next directory entry.
>
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
> src/storage/storage_backend_scsi.c | 20 ++++++++++++++++++--
> 1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c
> index e6c8bb5..c5105ec 100644
> --- a/src/storage/storage_backend_scsi.c
> +++ b/src/storage/storage_backend_scsi.c
> @@ -329,6 +329,15 @@ getOldStyleBlockDevice(const char *lun_path ATTRIBUTE_UNUSED,
> }
>
>
> +/*
> + * Search a device entry for the "block" file
> + *
> + * Returns
> + *
> + * 0 => Found it
> + * -1 => Fatal error
> + * -2 => Didn't find in lun_path directory
> + */
> static int
> getBlockDevice(uint32_t host,
> uint32_t bus,
> @@ -354,6 +363,10 @@ getBlockDevice(uint32_t host,
> goto out;
> }
>
> + /* As long as virDirRead doesn't fail, if we fail to find the
> + * "block" file in this directory, allow caller to continue
> + */
> + retval = -2;
> while ((direrr = virDirRead(lun_dir, &lun_dirent, lun_path)) > 0) {
> if (STREQLEN(lun_dirent->d_name, "block", 5)) {
> if (strlen(lun_dirent->d_name) == 5) {
> @@ -368,6 +381,9 @@ getBlockDevice(uint32_t host,
> break;
> }
> }
> + /* Keep retval = -2 unless there was a fatal error in virDirRead */
> + if (retval == -2 && direrr < 0)
> + retval = -1;
>
> closedir(lun_dir);
>
> @@ -417,9 +433,9 @@ processLU(virStoragePoolObjPtr pool,
> VIR_DEBUG("%u:%u:%u:%u is a Direct-Access LUN",
> host, bus, target, lun);
>
> - if (getBlockDevice(host, bus, target, lun, &block_device) < 0) {
> + if ((retval = getBlockDevice(host, bus, target, lun, &block_device)) < 0) {
> VIR_DEBUG("Failed to find block device for this LUN");
> - return -1;
> + return retval;
> }
>
> retval = virStorageBackendSCSINewLun(pool, host, bus, target, lun,
>
While this would work, I think if we follow out the pattern from the
rest of our functions, we can do better. Let me propose v2 to express
what I have in mind.
Michal
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