def _detect_block_size(cls, sd_id, mountpoint):
"""
Detect filesystem block size and validate direct I/O usage.
There is no way to get the underlying block size, but ioprocess can
detect it by writing to storage using direct I/O.
Raises:
se.StorageDomainTargetUnsupported if the underlying storage does
not support direct I/O.
OSError if probing block size failed because of another error.
ioprocess.Timeout if writing to storage timed out.
Returns:
the detected block size (1, 512, 4096)
"""
log = logging.getLogger("storage.fileSD")
iop = oop.getProcessPool(sd_id)
try:
block_size = iop.probe_block_size(mountpoint)
except OSError as e:
if e.errno != errno.EINVAL:
raise
raise se.StorageDomainTargetUnsupported(
"Failed to probe block size on {}: {}".format(mountpoint, e))
log.debug("Detected domain %s block size %s", sd_id, block_size)
return block_size
def validateFileSystemFeatures(sdUUID, mountDir):
try:
# Don't unlink this file, we don't have the cluster lock yet as it
# requires direct IO which is what we are trying to test for. This
# means that unlinking the file might cause a race. Since we don't
# care what the content of the file is, just that we managed to
# open it O_DIRECT.
testFilePath = os.path.join(mountDir, "__DIRECT_IO_TEST__")
oop.getProcessPool(sdUUID).directTouch(testFilePath)
except OSError as e:
if e.errno == errno.EINVAL:
log = logging.getLogger("storage.fileSD")
log.error("Underlying file system doesn't support" "direct IO")
raise se.StorageDomainTargetUnsupported()
raise
def _detect_block_size(cls, sd_id, mountpoint):
"""
Detect filesystem block size and validate direct I/O usage.
There is no way to get the underlying storage logical block size, but
since direct I/O must be aligned to the logical block size, we can
detect the capability by trying to write a file using direct I/O.
This creates a file __DIRECT_IO_TEST__ in the mountpoint. Removing this
file is racy so we leave it.
Raises:
se.StorageDomainTargetUnsupported if direct I/O fails for all
supported block sizes.
OSError if writing failed because of another error.
ioprocess.Timeout if writing to storage timed out.
Returns:
the detected block size (1, 512, 4096)
"""
log = logging.getLogger("storage.fileSD")
path = os.path.join(mountpoint, "__DIRECT_IO_TEST__")
iop = oop.getProcessPool(sd_id)
for block_size in (sc.BLOCK_SIZE_NONE, sc.BLOCK_SIZE_512,
sc.BLOCK_SIZE_4K):
log.debug("Trying block size %s", block_size)
data = b"\0" * block_size
try:
iop.writeFile(path, data, direct=True)
except OSError as e:
if e.errno != errno.EINVAL:
raise
else:
log.debug("Detected domain %s block size %s", sd_id,
block_size)
return block_size
raise se.StorageDomainTargetUnsupported(
"Failed to write to {} using direct I/O".format(path))