Since directories can be used for <filesystem> passthrough, they are
basically storage volumes.
v2:
Skip ., .., lost+found dirs
v3:
Use gnulib last_component
v4:
Use gnulib "dirname.h", not system <dirname.h>
Don't skip lost+found
When libvirt starts up all storage pools default to the inactive
state, even if the underlying storage is already active on the
host. This introduces a new API into the internal storage backend
drivers that checks whether a storage pool is already active. If
the pool is active at libvirtd startup, the volume list will be
immediately populated.
* src/storage/storage_backend.h: New internal API for checking
storage pool state
* src/storage/storage_driver.c: Check whether a pool is active
upon driver startup
* src/storage/storage_backend_fs.c, src/storage/storage_backend_iscsi.c,
src/storage/storage_backend_logical.c, src/storage/storage_backend_mpath.c,
src/storage/storage_backend_scsi.c: Add checks for pool state
If a directory pool contains pipes or sockets, a pool start can fail or hang:
https://bugzilla.redhat.com/show_bug.cgi?id=589577
We already try to avoid these special files, but only attempt after
opening the path, which is where the problems lie. Unify volume opening
into helper functions, which use the proper open() flags to avoid error,
followed by fstat to validate storage mode.
Previously, virStorageBackendUpdateVolTargetInfoFD attempted to enforce the
storage mode check, but allowed callers to detect this case and silently
continue. In practice, only the FS backend was using this feature, the rest
were treating unknown mode as an error condition. Unfortunately the InfoFD
function wasn't raising an error message here, so error reporting was
busted.
This patch adds 2 functions: virStorageBackendVolOpen, and
virStorageBackendVolOpenModeSkip. The latter retains the original opt out
semantics, the former now throws an explicit error.
This patch maintains the previous volume mode checks: allowing specific
modes for specific pool types requires a bit of surgery, since VolOpen
is called through several different helper functions.
v2: Use ATTRIBUTE_NONNULL. Drop stat check, just open with
O_NONBLOCK|O_NOCTTY.
v3: Move mode check logic back to VolOpen. Use 2 VolOpen functions with
different error semantics.
v4: Make second VolOpen function more extensible. Didn't opt to change
FS backend defaults, this can just be to fix the original bug.
v5: Prefix default flags with VIR_, use ATTRIBUTE_RETURN_CHECK
Volume detection in the scsi backend was duplicating code already
present in storage_backend.c. Let's drop the duplicate code.
Also, change the shared function name to be less generic, and remove
some error squashing in the other call site.
The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in storage_conf.{h,c} and storage_encryption_conf.{h,c}
and update all callers to match
In order to avoid problems trying to chown files that were created by
root on a root-squashing nfs server, fork a new process that setuid's
to the desired uid before creating the file. (It's only done this way
if the pool containing the new volume is of type 'netfs', otherwise
the old method of creating the file followed by chown() is used.)
This changes the semantics of the "create_func" slightly - previously
it was assumed that this function just created the file, then the
caller would chown it to the desired uid. Now, create_func does both
operations.
There are multiple functions that can take on the role of create_func:
createFileDir - previously called mkdir(), now calls virDirCreate().
virStorageBackendCreateRaw - previously called open(),
now calls virFileCreate().
virStorageBackendCreateQemuImg - use virRunWithHook() to setuid/gid.
virStorageBackendCreateQcowCreate - same.
virStorageBackendCreateBlockFrom - preserve old behavior (but attempt
chown when necessary even if not root)
* src/storage/storage_backend.[ch] src/storage/storage_backend_disk.c
src/storage/storage_backend_fs.c src/storage/storage_backend_logical.c
src/storage/storage_driver.c: change the create_func implementations,
also propagate the pool information to be able to detect NETFS ones.
