[libvirt] [PATCH 2/6] conf: earlier allocation during backing chain crawl
Eric Blake
eblake at redhat.com
Wed Apr 9 04:35:19 UTC 2014
Right now, we are allocating virStorageFileMetadata near the bottom
of the callchain, only after we have identified that we are visiting
a file (and not a network resource). I'm hoping to eventually
support parsing the backing chain from XML, where the backing chain
crawl then validates what was parsed rather than allocating a fresh
structure. Likewise, I'm working towards a setup where we have a
backing element even for networks. Both of these use cases are
easier to code if the allocation is hoisted earlier.
* src/util/virstoragefile.c (virStorageFileGetMetadataInternal)
(virStorageFileGetMetadataFromFDInternal): Change signature.
(virStorageFileGetMetadataFromBuf)
(virStorageFileGetMetadataRecurse, virStorageFileGetMetadata):
Update callers.
Signed-off-by: Eric Blake <eblake at redhat.com>
---
src/util/virstoragefile.c | 126 +++++++++++++++++++++++++++-------------------
1 file changed, 75 insertions(+), 51 deletions(-)
diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 336842c..e516acf 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -771,26 +771,24 @@ qcow2GetFeatures(virBitmapPtr *features,
/* Given a header in BUF with length LEN, as parsed from the file with
* user-provided name PATH and opened from CANONPATH, and where any
- * relative backing file will be opened from DIRECTORY, return
- * metadata about that file, assuming it has the given FORMAT. */
-static virStorageFileMetadataPtr ATTRIBUTE_NONNULL(1)
-ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4)
+ * relative backing file will be opened from DIRECTORY, and assuming
+ * it has the given FORMAT, populate the newly-allocated META with
+ * information about the file and its backing store. */
+static int ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2)
+ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4) ATTRIBUTE_NONNULL(7)
virStorageFileGetMetadataInternal(const char *path,
const char *canonPath,
const char *directory,
char *buf,
size_t len,
- int format)
+ int format,
+ virStorageFileMetadataPtr meta)
{
- virStorageFileMetadata *meta = NULL;
- virStorageFileMetadata *ret = NULL;
+ int ret = -1;
VIR_DEBUG("path=%s, canonPath=%s, dir=%s, buf=%p, len=%zu, format=%d",
path, canonPath, directory, buf, len, format);
- if (VIR_ALLOC(meta) < 0)
- return NULL;
-
if (format == VIR_STORAGE_FILE_AUTO)
format = virStorageFileProbeFormatFromBuf(path, buf, len);
@@ -886,11 +884,9 @@ virStorageFileGetMetadataInternal(const char *path,
goto cleanup;
done:
- ret = meta;
- meta = NULL;
+ ret = 0;
cleanup:
- virStorageFileFreeMetadata(meta);
return ret;
}
@@ -981,44 +977,52 @@ virStorageFileGetMetadataFromBuf(const char *path,
size_t len,
int format)
{
- virStorageFileMetadataPtr ret;
+ virStorageFileMetadataPtr ret = NULL;
char *canonPath;
if (!(canonPath = canonicalize_file_name(path))) {
virReportSystemError(errno, _("unable to resolve '%s'"), path);
return NULL;
}
+ if (VIR_ALLOC(ret) < 0)
+ goto cleanup;
+
+ if (virStorageFileGetMetadataInternal(path, canonPath, ".", buf, len,
+ format, ret) < 0) {
+ virStorageFileFreeMetadata(ret);
+ ret = NULL;
+ }
- ret = virStorageFileGetMetadataInternal(path, canonPath, ".", buf, len,
- format);
+ cleanup:
VIR_FREE(canonPath);
return ret;
}
/* Internal version that also supports a containing directory name. */
-static virStorageFileMetadataPtr
+static int
virStorageFileGetMetadataFromFDInternal(const char *path,
const char *canonPath,
const char *directory,
int fd,
- int format)
+ int format,
+ virStorageFileMetadataPtr meta)
{
char *buf = NULL;
ssize_t len = VIR_STORAGE_MAX_HEADER;
struct stat sb;
- virStorageFileMetadataPtr ret = NULL;
+ int ret = -1;
if (fstat(fd, &sb) < 0) {
virReportSystemError(errno,
_("cannot stat file '%s'"),
path);
- return NULL;
+ return -1;
}
/* No header to probe for directories, but also no backing file */
if (S_ISDIR(sb.st_mode)) {
- ignore_value(VIR_ALLOC(ret));
+ ret = 0;
goto cleanup;
}
@@ -1033,7 +1037,8 @@ virStorageFileGetMetadataFromFDInternal(const char *path,
}
ret = virStorageFileGetMetadataInternal(path, canonPath, directory,
- buf, len, format);
+ buf, len, format, meta);
+
cleanup:
VIR_FREE(buf);
return ret;
@@ -1063,71 +1068,81 @@ virStorageFileGetMetadataFromFD(const char *path,
int fd,
int format)
{
- virStorageFileMetadataPtr ret;
+ virStorageFileMetadataPtr ret = NULL;
char *canonPath;
if (!(canonPath = canonicalize_file_name(path))) {
virReportSystemError(errno, _("unable to resolve '%s'"), path);
return NULL;
}
- ret = virStorageFileGetMetadataFromFDInternal(path, canonPath, ".",
- fd, format);
+ if (VIR_ALLOC(ret) < 0)
+ goto cleanup;
+ if (virStorageFileGetMetadataFromFDInternal(path, canonPath, ".",
+ fd, format, ret) < 0) {
+ virStorageFileFreeMetadata(ret);
+ ret = NULL;
+ }
+
+ cleanup:
VIR_FREE(canonPath);
return ret;
}
/* Recursive workhorse for virStorageFileGetMetadata. */
-static virStorageFileMetadataPtr
+static int
virStorageFileGetMetadataRecurse(const char *path, const char *canonPath,
const char *directory,
int format, uid_t uid, gid_t gid,
- bool allow_probe, virHashTablePtr cycle)
+ bool allow_probe, virHashTablePtr cycle,
+ virStorageFileMetadataPtr meta)
{
int fd;
+ int ret = -1;
VIR_DEBUG("path=%s canonPath=%s dir=%s format=%d uid=%d gid=%d probe=%d",
path, canonPath, NULLSTR(directory), format,
(int)uid, (int)gid, allow_probe);
- virStorageFileMetadataPtr ret = NULL;
-
if (virHashLookup(cycle, canonPath)) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("backing store for %s is self-referential"),
path);
- return NULL;
+ return -1;
}
if (virHashAddEntry(cycle, canonPath, (void *)1) < 0)
- return NULL;
+ return -1;
if ((fd = virFileOpenAs(canonPath, O_RDONLY, 0, uid, gid, 0)) < 0) {
virReportSystemError(-fd, _("Failed to open file '%s'"), path);
- return NULL;
+ return -1;
}
ret = virStorageFileGetMetadataFromFDInternal(path, canonPath, directory,
- fd, format);
+ fd, format, meta);
if (VIR_CLOSE(fd) < 0)
VIR_WARN("could not close file %s", path);
- if (ret && ret->backingStoreIsFile) {
- if (ret->backingStoreFormat == VIR_STORAGE_FILE_AUTO && !allow_probe)
- ret->backingStoreFormat = VIR_STORAGE_FILE_RAW;
- else if (ret->backingStoreFormat == VIR_STORAGE_FILE_AUTO_SAFE)
- ret->backingStoreFormat = VIR_STORAGE_FILE_AUTO;
- format = ret->backingStoreFormat;
- ret->backingMeta = virStorageFileGetMetadataRecurse(ret->backingStoreRaw,
- ret->backingStore,
- ret->directory,
- format,
- uid, gid,
- allow_probe,
- cycle);
- if (!ret->backingMeta) {
+ if (ret == 0 && meta->backingStoreIsFile) {
+ virStorageFileMetadataPtr backing;
+
+ if (meta->backingStoreFormat == VIR_STORAGE_FILE_AUTO && !allow_probe)
+ meta->backingStoreFormat = VIR_STORAGE_FILE_RAW;
+ else if (meta->backingStoreFormat == VIR_STORAGE_FILE_AUTO_SAFE)
+ meta->backingStoreFormat = VIR_STORAGE_FILE_AUTO;
+ format = meta->backingStoreFormat;
+ if (VIR_ALLOC(backing) < 0 ||
+ virStorageFileGetMetadataRecurse(meta->backingStoreRaw,
+ meta->backingStore,
+ meta->directory, format,
+ uid, gid, allow_probe,
+ cycle, backing) < 0) {
/* If we failed to get backing data, mark the chain broken */
- ret->backingStoreFormat = VIR_STORAGE_FILE_NONE;
- VIR_FREE(ret->backingStore);
+ meta->backingStoreFormat = VIR_STORAGE_FILE_NONE;
+ VIR_FREE(meta->backingStore);
+ virStorageFileFreeMetadata(backing);
+ } else {
+ meta->backingMeta = backing;
}
}
return ret;
@@ -1164,6 +1179,7 @@ virStorageFileGetMetadata(const char *path, int format,
path, format, (int)uid, (int)gid, allow_probe);
virHashTablePtr cycle = virHashCreate(5, NULL);
+ virStorageFileMetadataPtr meta = NULL;
virStorageFileMetadataPtr ret = NULL;
char *canonPath = NULL;
char *directory = NULL;
@@ -1179,12 +1195,20 @@ virStorageFileGetMetadata(const char *path, int format,
virReportOOMError();
goto cleanup;
}
+ if (VIR_ALLOC(meta) < 0)
+ goto cleanup;
if (format <= VIR_STORAGE_FILE_NONE)
format = allow_probe ? VIR_STORAGE_FILE_AUTO : VIR_STORAGE_FILE_RAW;
- ret = virStorageFileGetMetadataRecurse(path, canonPath, directory, format,
- uid, gid, allow_probe, cycle);
+ if (virStorageFileGetMetadataRecurse(path, canonPath, directory, format,
+ uid, gid, allow_probe, cycle,
+ meta) < 0)
+ goto cleanup;
+ ret = meta;
+ meta = NULL;
+
cleanup:
+ virStorageFileFreeMetadata(meta);
VIR_FREE(canonPath);
VIR_FREE(directory);
virHashFree(cycle);
--
1.9.0
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