On 03/31/2014 12:50 PM, Cole Robinson wrote:
> VolOpen notifies the user of a potentially non-fatal failure by
> returning -2 and logging a VIR_WARN or VIR_INFO. Unfortunately most
> callers treat -2 as fatal but don't actually report any message with
> the error APIs.
>
> Change VolOpen to report an error if the VOL_OPEN_ERROR flag is passed.
> The ony caller that doesn't use this flag is the one that is explicitly
> handling -2 return code, so it fits the pattern.
>
> Tweak some of the other call sites to propagate the newly raised error.
> ---
> src/storage/storage_backend.c | 60 ++++++++++++++++++++++++-----------
> src/storage/storage_backend_fs.c | 21 ++++++------
> src/storage/storage_backend_logical.c | 6 +++-
> src/storage/storage_backend_scsi.c | 4 +--
> 4 files changed, 59 insertions(+), 32 deletions(-)
>
> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
> index 42bd445..7c1220e 100644
> --- a/src/storage/storage_backend.c
> +++ b/src/storage/storage_backend.c
> @@ -1273,10 +1273,11 @@ virStorageBackendDetectBlockVolFormatFD(virStorageVolTargetPtr target,
>
>
> /*
> - * Allows caller to silently ignore files with improper mode
> - *
> * Returns -1 on error, -2 if file mode is unexpected or the
> * volume is a dangling symbolic link.
> + *
> + * -2 can be an ignorable error, but callers have to make sure to
> + * virResetLastError()
> */
Is this comment still accurate?
> char *base = last_component(path);
> + bool raise_error = (flags & VIR_STORAGE_VOL_OPEN_ERROR);
Hmm - are the semantics of this flag backwards? If most users always
want an error, and only one specific caller wants the error suppressed
because it is prepared to deal with a -2 return, shouldn't the default
be errors when flags==0, and the one caller pass a non-zero flag for
VIR_STORAGE_VOL_OPEN_NOERROR?
>
> if (lstat(path, sb) < 0) {
> - if (errno == ENOENT && !(flags & VIR_STORAGE_VOL_OPEN_ERROR)) {
> + if (errno == ENOENT && !raise_error) {
> VIR_WARN("ignoring missing file '%s'", path);
> return -2;
> }
> - virReportSystemError(errno,
> - _("cannot stat file '%s'"),
> - path);
> +
> + virReportSystemError(errno, _("cannot stat file '%s'"), path);
> return -1;
This is an unconditional error, even when the flags say the user doesn't
want errors; do we need to tweak the docs to mention that we are only
suppressing SOME errors, not all?
> @@ -82,8 +82,11 @@ virStorageBackendProbeTarget(virStorageVolTargetPtr target,
> *encryption = NULL;
>
> if ((ret = virStorageBackendVolOpen(target->path, &sb,
> - VIR_STORAGE_VOL_FS_REFRESH_FLAGS)) < 0)
> - goto error; /* Take care to propagate ret, it is not always -1 */
> + VIR_STORAGE_VOL_FS_REFRESH_FLAGS)) < 0) {
> + /* ret == -2 is non-fatal, propage the return code so the caller
s/propage/propagate/
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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