4:23 p.m.
Similar to the openflags VIR_STORAGE_VOL_OPEN_NOERROR processing, if some
read processing operation fails, check the readflags for the corresponding
error flag being set. If so, rather then causing an error - use VIR_WARN
to flag the error, but return -2 which some callers can use to perform
specific actions. Use a new VIR_STORAGE_VOL_READ_NOERROR flag in a new
VolReadErrorMode enum.
Signed-off-by: John Ferlan <jferlan(a)redhat.com>
---
src/storage/storage_backend.c | 43 +++++++++++++++++++++++++++++++------------
src/storage/storage_backend.h | 9 +++++++++
2 files changed, 40 insertions(+), 12 deletions(-)
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index 8eb5b04..c29b162 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -1393,14 +1393,17 @@ static struct diskType const disk_types[] = {
* virStorageBackendDetectBlockVolFormatFD
* @target: target definition ptr of volume to update
* @fd: fd of storage volume to update,
- * @readflags: unused
+ * @readflags: VolReadErrorMode flags to handle read error after open
+ * is successful, but read is not.
*
- * Returns 0 for success, -1 on a legitimate error condition
+ * Returns 0 for success, -1 on a legitimate error condition, -2 if
+ * the read error is desired to be ignored (along with appropriate
+ * VIR_WARN of the issue).
*/
static int
virStorageBackendDetectBlockVolFormatFD(virStorageSourcePtr target,
int fd,
- unsigned int readflags ATTRIBUTE_UNUSED)
+ unsigned int readflags)
{
size_t i;
off_t start;
@@ -1419,10 +1422,16 @@ virStorageBackendDetectBlockVolFormatFD(virStorageSourcePtr
target,
}
bytes = saferead(fd, buffer, sizeof(buffer));
if (bytes < 0) {
- virReportSystemError(errno,
- _("cannot read beginning of file '%s'"),
- target->path);
- return -1;
+ if (readflags & VIR_STORAGE_VOL_READ_NOERROR) {
+ VIR_WARN("ignoring failed saferead of file '%s'",
+ target->path);
+ return -2;
+ } else {
+ virReportSystemError(errno,
+ _("cannot read beginning of file
'%s'"),
+ target->path);
+ return -1;
+ }
}
for (i = 0; disk_types[i].part_table_type != -1; i++) {
@@ -1591,11 +1600,13 @@ virStorageBackendVolOpen(const char *path, struct stat *sb,
* @target: target definition ptr of volume to update
* @withBlockVolFormat: true if caller determined a block file
* @openflags: various VolOpenCheckMode flags to handle errors on open
- * @readflags: unused
+ * @readflags: VolReadErrorMode flags to handle read error after open
+ * is successful, but read is not.
*
* Returns 0 for success, -1 on a legitimate error condition, and -2
* if the openflags used VIR_STORAGE_VOL_OPEN_NOERROR and some sort of
- * open error occurred. It is up to the caller to handle.
+ * open error occurred. It is up to the caller to handle. A -2 may also
+ * be returned if the caller passed a readflagsflag.
*/
int
virStorageBackendUpdateVolTargetInfo(virStorageSourcePtr target,
@@ -1630,8 +1641,16 @@ virStorageBackendUpdateVolTargetInfo(virStorageSourcePtr target,
}
if ((len = virFileReadHeaderFD(fd, len, &buf)) < 0) {
- virReportSystemError(errno, _("cannot read header '%s'"),
target->path);
- ret = -1;
+ if (readflags & VIR_STORAGE_VOL_READ_NOERROR) {
+ VIR_WARN("ignoring failed header read for '%s'",
+ target->path);
+ ret = -2;
+ } else {
+ virReportSystemError(errno,
+ _("cannot read header '%s'"),
+ target->path);
+ ret = -1;
+ }
goto cleanup;
}
@@ -1663,7 +1682,7 @@ virStorageBackendUpdateVolTargetInfo(virStorageSourcePtr target,
* @vol: Pointer to a volume storage definition
* @withBlockVolFormat: true if the caller determined a block file
* @openflags: various VolOpenCheckMode flags to handle errors on open
- * @readflags: unused
+ * @readflags: various VolReadErrorMode flags to handle errors on read
*
* Returns 0 for success, -1 on a legitimate error condition, and -2
* if the openflags used VIR_STORAGE_VOL_OPEN_NOERROR and some sort of
diff --git a/src/storage/storage_backend.h b/src/storage/storage_backend.h
index 64c46ee..20e6079 100644
--- a/src/storage/storage_backend.h
+++ b/src/storage/storage_backend.h
@@ -179,6 +179,15 @@ enum {
VIR_STORAGE_VOL_OPEN_DIR = 1 << 4, /* directories okay */
};
+/* VolReadErrorMode flags
+ * If flag is present, then operation won't cause fatal error for
+ * specified operation, rather a VIR_WARN will be issued and a -2 returned
+ * for function call
+ */
+enum {
+ VIR_STORAGE_VOL_READ_NOERROR = 1 << 0, /* ignore *read errors */
+};
+
# define VIR_STORAGE_VOL_OPEN_DEFAULT (VIR_STORAGE_VOL_OPEN_REG |\
VIR_STORAGE_VOL_OPEN_BLOCK)
--
2.5.0