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