On Wed, Jan 27, 2016 at 09:04:45AM -0500, John Ferlan wrote:
On 01/26/2016 09:46 AM, Pavel Hrdina wrote:
On Fri, Jan 22, 2016 at 05:21:04PM -0500, John Ferlan wrote:
Create a helper routine in order to parse the 'device' string contained within the generated 'lvs' output string.
A future patch would then be able to avoid the code more cleanly
Signed-off-by: John Ferlan <jferlan@redhat.com> --- src/storage/storage_backend_logical.c | 186 +++++++++++++++++++--------------- 1 file changed, 104 insertions(+), 82 deletions(-)
diff --git a/src/storage/storage_backend_logical.c b/src/storage/storage_backend_logical.c index 76ea00a..bf67faf 100644 --- a/src/storage/storage_backend_logical.c +++ b/src/storage/storage_backend_logical.c @@ -72,21 +72,115 @@ struct virStorageBackendLogicalPoolVolData { };
static int -virStorageBackendLogicalMakeVol(char **const groups, - void *opaque) +virStorageBackendLogicalParseVolDevice(virStorageVolDefPtr vol, + char **const groups, + int nextents, + unsigned long long size, + unsigned long long length) {
You've called the new helper *ParseVolDevice, but it actually does more than that. I would rather see it like ParseExtents and also move all the extents related code into this function (parsing length and size)
OK - my goal was to just parse the devices/extents element so that the next patch could use the 'nextents' to decide whether to call it... The 'nextents' is just the count... Having more than 1 is seen in a 'striped' and 'mirror' lv. A 'thin' lv has 0... A 'thin-pool' and 'linear' each has 1... Names are found in the 'segtype' field, but it's otherwise useless. Perhaps originally the thought when adding a parse of that field was that the 'stripes' value only was valid for stripes and mirrors, but it seems it's set depending on the count of devices - so it seems safe to use it for the extents parsing.
FWIW: The "extents" look like:
/dev/hda2(0) <--- linear
or
/dev/sdc1(10240),/dev/sdd1(0) <--- striped
or
thinpool_lv_test_thin_tdata(0) <--- thin-pool
The "extents" gets further 'regcomp' and 'regexec''d to grab that "(#)" which is part of the black magic that I cannot explain ;-)
Yes, I understand why the next patch updates the way, that we don't assume there is always 1 extent. It just seemed to me that parsing length and size would be nice to move to that function as it's used only in that function.
[...]
+ /* vars[0] is skipped */ + for (i = 0; i < nextents; i++) { + size_t j; + int len; + char *offset_str = NULL; + + j = (i * 2) + 1; + len = vars[j].rm_eo - vars[j].rm_so; + p[vars[j].rm_eo] = '\0'; + + if (VIR_STRNDUP(vol->source.extents[vol->source.nextent].path, + p + vars[j].rm_so, len) < 0) + goto cleanup; + + len = vars[j + 1].rm_eo - vars[j + 1].rm_so; + if (VIR_STRNDUP(offset_str, p + vars[j + 1].rm_so, len) < 0) + goto cleanup; + + if (virStrToLong_ull(offset_str, NULL, 10, &offset) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed volume extent offset value")); + VIR_FREE(offset_str); + goto cleanup; + } + + VIR_FREE(offset_str); + + vol->source.extents[vol->source.nextent].start = offset * size; + vol->source.extents[vol->source.nextent].end = (offset * size) + length; + vol->source.nextent++;
This would be much nicer to be done using VIR_APPEND_ELEMENT(). I know that this commit is just a code movement so this should be done in separate commit.
Yes I pretty much blindly moved "just" the devices parsing code, but I will note that we're not appending here - it's filling it in. Back in the caller "vol->source.extents" is allocated using "vol->source.nextents + nextents". A "new" vol would have "source.nextents == 0". All this loop does is fill in each source.extents and bump the source.nextents.
Yes, I know that we are not appending but filling existing array that was allocated earlier, I just didn't mentioned it. But we don't need to pre-allocate the array but just simply use append_element. The main point was that the allocation is again outside of the new function and that's not a good practice.
In any case, I will move the allocation of source.extents, fetch of length and size into the helper (and rename it).