x/swiftonfile
Code Issues Proposed changes

Introduce fallocate support

Browse Source 
fallocate() allows for reserving disk space for a particular inode and
fd. Hence, a client can be sure that he won't see a ENOSPC (eventually
a 507 HTTP response) later during writes. Swift's object server has
had fallocate() support from a long time.

P.S: Older versions of glusterfs (<3.6) did not support fallocate
because FUSE did not support it earlier.
http://review.gluster.org/4969
http://fuse.996288.n3.nabble.com/fallocate-support-in-FUSE-td10668.html

Change-Id: Ida4b16357901707d624f92bf1b2dc8f07da4f1ad
Signed-off-by: Prashanth Pai <ppai@redhat.com>
This commit is contained in:
Prashanth Pai 2015-06-03 12:31:40 +05:30
parent 60eaebbb01
commit 9e65dd9ceb
3 changed files with 27 additions and 9 deletions
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9
etc/object-server.conf-swiftonfile
View File

@ -20,8 +20,13 @@ max_clients = 1024
# If not doing the above, setting this value initially to match the number of
# CPUs is a good starting point for determining the right value.
workers = 1
# Override swift's default behaviour for fallocate.
disable_fallocate = true
# You can set disable_fallocate to true to turn off usage of fallocate()
# sys call to reserve space during a PUT operation.
# disable_fallocate = false
#
# You can set fallocate_reserve to the number of bytes you'd like fallocate to
# reserve, whether there is space for the given file size or not.
# fallocate_reserve = 0
[pipeline:main]
pipeline = object-server

14
swiftonfile/swift/obj/diskfile.py
View File

@ -28,7 +28,8 @@ from eventlet import sleep
from contextlib import contextmanager
from swiftonfile.swift.common.exceptions import AlreadyExistsAsFile, \
AlreadyExistsAsDir
from swift.common.utils import ThreadPool, hash_path, normalize_timestamp
from swift.common.utils import ThreadPool, hash_path, \
normalize_timestamp, fallocate
from swift.common.exceptions import DiskFileNotExist, DiskFileError, \
DiskFileNoSpace, DiskFileDeviceUnavailable, DiskFileNotOpen, \
DiskFileExpired
@ -931,14 +932,19 @@ class DiskFile(object):
break
dw = None
try:
if size is not None and size > 0:
try:
fallocate(fd, size)
except OSError as err:
if err.errno in (errno.ENOSPC, errno.EDQUOT):
raise DiskFileNoSpace()
raise
# Ensure it is properly owned before we make it available.
do_fchown(fd, self._uid, self._gid)
# NOTE: we do not perform the fallocate() call at all. We ignore
# it completely since at the time of this writing FUSE does not
# support it.
dw = DiskFileWriter(fd, tmppath, self)
yield dw
finally:
if dw:
dw.close()
if dw._tmppath:
do_unlink(dw._tmppath)

7
test/unit/obj/test_diskfile.py
View File

@ -89,6 +89,10 @@ def _mock_do_fsync(fd):
return
def _mock_fallocate(fd, size):
return
class MockRenamerCalled(Exception):
pass
@ -134,6 +138,8 @@ class TestDiskFile(unittest.TestCase):
swiftonfile.swift.common.utils.read_metadata = _mock_read_metadata
self._saved_do_fsync = swiftonfile.swift.obj.diskfile.do_fsync
swiftonfile.swift.obj.diskfile.do_fsync = _mock_do_fsync
self._saved_fallocate = swiftonfile.swift.obj.diskfile.fallocate
swiftonfile.swift.obj.diskfile.fallocate = _mock_fallocate
self.td = tempfile.mkdtemp()
self.conf = dict(devices=self.td, mb_per_sync=2,
keep_cache_size=(1024 * 1024), mount_check=False)
@ -148,6 +154,7 @@ class TestDiskFile(unittest.TestCase):
swiftonfile.swift.common.utils.write_metadata = self._saved_ut_wm
swiftonfile.swift.common.utils.read_metadata = self._saved_ut_rm
swiftonfile.swift.obj.diskfile.do_fsync = self._saved_do_fsync
swiftonfile.swift.obj.diskfile.fallocate = self._saved_fallocate
shutil.rmtree(self.td)
def _get_diskfile(self, d, p, a, c, o, **kwargs):