summaryrefslogtreecommitdiffstats
path: root/gluster/swift/common/fs_utils.py
blob: 03c5a77a7e2338dd184e9ca0f51aadaf93ff6b51 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
# Copyright (c) 2012-2013 Red Hat, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import logging
import os
import errno
import stat
import random
import time
from collections import defaultdict
from itertools import repeat
import ctypes
import os.path as _os_path
from eventlet import sleep
from swift.common.utils import load_libc_function
from gluster.swift.common.exceptions import FileOrDirNotFoundError, \
    NotDirectoryError, GlusterFileSystemOSError
from swift.common.exceptions import DiskFileNoSpace


os_path = _os_path


def do_walk(*args, **kwargs):
    return os.walk(*args, **kwargs)


def do_write(fd, buf):
    try:
        cnt = os.write(fd, buf)
    except OSError as err:
        filename = get_filename_from_fd(fd)
        if err.errno in (errno.ENOSPC, errno.EDQUOT):
            do_log_rl("do_write(%d, msg[%d]) failed: %s : %s",
                      fd, len(buf), err, filename)
            raise DiskFileNoSpace()
        else:
            raise GlusterFileSystemOSError(
                err.errno, '%s, os.write("%s", ...)' % (err.strerror, fd))
    return cnt


def do_read(fd, n):
    try:
        buf = os.read(fd, n)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.write("%s", ...)' % (err.strerror, fd))
    return buf


def do_ismount(path):
    """
    Test whether a path is a mount point.

    This is code hijacked from C Python 2.6.8, adapted to remove the extra
    lstat() system call.
    """
    try:
        s1 = os.lstat(path)
    except os.error as err:
        if err.errno == errno.ENOENT:
            # It doesn't exist -- so not a mount point :-)
            return False
        else:
            raise GlusterFileSystemOSError(
                err.errno, '%s, os.lstat("%s")' % (err.strerror, path))

    if stat.S_ISLNK(s1.st_mode):
        # A symlink can never be a mount point
        return False

    try:
        s2 = os.lstat(os.path.join(path, '..'))
    except os.error as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.lstat("%s")' % (err.strerror,
                                               os.path.join(path, '..')))

    dev1 = s1.st_dev
    dev2 = s2.st_dev
    if dev1 != dev2:
        # path/.. on a different device as path
        return True

    ino1 = s1.st_ino
    ino2 = s2.st_ino
    if ino1 == ino2:
        # path/.. is the same i-node as path
        return True

    return False


def do_mkdir(path):
    try:
        os.mkdir(path)
    except OSError as err:
        if err.errno == errno.EEXIST:
            logging.warn("fs_utils: os.mkdir - path %s already exists", path)
        elif err.errno in (errno.ENOSPC, errno.EDQUOT):
            do_log_rl("do_mkdir(%s) failed: %s", path, err)
            raise DiskFileNoSpace()
        else:
            raise GlusterFileSystemOSError(
                err.errno, '%s, os.mkdir("%s")' % (err.strerror, path))


def do_listdir(path):
    try:
        buf = os.listdir(path)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.listdir("%s")' % (err.strerror, path))
    return buf


def dir_empty(path):
    """
    Return true if directory is empty (or does not exist), false otherwise.

    :param path: Directory path
    :returns: True/False
    """
    try:
        files = do_listdir(path)
        return not files
    except GlusterFileSystemOSError as err:
        if err.errno == errno.ENOENT:
            raise FileOrDirNotFoundError()
        if err.errno == errno.ENOTDIR:
            raise NotDirectoryError()
        raise


def do_rmdir(path):
    try:
        os.rmdir(path)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.rmdir("%s")' % (err.strerror, path))


def do_chown(path, uid, gid):
    try:
        os.chown(path, uid, gid)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.chown("%s", %s, %s)' % (
                err.strerror, path, uid, gid))


def do_fchown(fd, uid, gid):
    try:
        os.fchown(fd, uid, gid)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.fchown(%s, %s, %s)' % (
                err.strerror, fd, uid, gid))


_STAT_ATTEMPTS = 10


def do_stat(path):
    serr = None
    for i in range(0, _STAT_ATTEMPTS):
        try:
            stats = os.stat(path)
        except OSError as err:
            if err.errno == errno.EIO:
                # Retry EIO assuming it is a transient error from FUSE after a
                # short random sleep
                serr = err
                sleep(random.uniform(0.001, 0.005))
                continue
            if err.errno == errno.ENOENT:
                stats = None
            else:
                raise GlusterFileSystemOSError(
                    err.errno, '%s, os.stat("%s")[%d attempts]' % (
                        err.strerror, path, i))
        if i > 0:
            logging.warn("fs_utils.do_stat():"
                         " os.stat('%s') retried %d times (%s)",
                         path, i, 'success' if stats else 'failure')
        return stats
    else:
        raise GlusterFileSystemOSError(
            serr.errno, '%s, os.stat("%s")[%d attempts]' % (
                serr.strerror, path, _STAT_ATTEMPTS))


def do_fstat(fd):
    try:
        stats = os.fstat(fd)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.fstat(%s)' % (err.strerror, fd))
    return stats


def do_open(path, flags, **kwargs):
    try:
        fd = os.open(path, flags, **kwargs)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.open("%s", %x, %r)' % (
                err.strerror, path, flags, kwargs))
    return fd


def do_close(fd):
    try:
        os.close(fd)
    except OSError as err:
        if err.errno in (errno.ENOSPC, errno.EDQUOT):
            filename = get_filename_from_fd(fd)
            do_log_rl("do_close(%d) failed: %s : %s",
                      fd, err, filename)
            raise DiskFileNoSpace()
        else:
            raise GlusterFileSystemOSError(
                err.errno, '%s, os.close(%s)' % (err.strerror, fd))


def do_unlink(path, log=True):
    try:
        os.unlink(path)
    except OSError as err:
        if err.errno != errno.ENOENT:
            raise GlusterFileSystemOSError(
                err.errno, '%s, os.unlink("%s")' % (err.strerror, path))
        elif log:
            logging.warn("fs_utils: os.unlink failed on non-existent path: %s",
                         path)


def do_rename(old_path, new_path):
    try:
        os.rename(old_path, new_path)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.rename("%s", "%s")' % (
                err.strerror, old_path, new_path))


def do_fsync(fd):
    try:
        os.fsync(fd)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.fsync("%s")' % (err.strerror, fd))


def do_fdatasync(fd):
    try:
        os.fdatasync(fd)
    except AttributeError:
        do_fsync(fd)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.fsync("%s")' % (err.strerror, fd))


_posix_fadvise = None


def do_fadvise64(fd, offset, length):
    global _posix_fadvise
    if _posix_fadvise is None:
        _posix_fadvise = load_libc_function('posix_fadvise64')
    # 4 means "POSIX_FADV_DONTNEED"
    _posix_fadvise(fd, ctypes.c_uint64(offset),
                   ctypes.c_uint64(length), 4)


def do_lseek(fd, pos, how):
    try:
        os.lseek(fd, pos, how)
    except OSError as err:
        raise GlusterFileSystemOSError(
            err.errno, '%s, os.fsync("%s")' % (err.strerror, fd))


def mkdirs(path):
    """
    Ensures the path is a directory or makes it if not. Errors if the path
    exists but is a file or on permissions failure.

    :param path: path to create
    """
    try:
        os.makedirs(path)
    except OSError as err:
        if err.errno == errno.EEXIST and os.path.isdir(path):
            return
        elif err.errno in (errno.ENOSPC, errno.EDQUOT):
            do_log_rl("mkdirs(%s) failed: %s", path, err)
            raise DiskFileNoSpace()
        else:
            raise GlusterFileSystemOSError(
                err.errno, '%s, os.makedirs("%s")' % (err.strerror, path))


def get_filename_from_fd(fd, verify=False):
    """
    Given the file descriptor, this method attempts to get the filename as it
    was when opened. This may not give accurate results in following cases:
    - file was renamed/moved/deleted after it was opened
    - file has multiple hardlinks

    :param fd: file descriptor of file opened
    :param verify: If True, performs additional checks using inode number
    """
    filename = None
    if isinstance(fd, int):
        try:
            filename = os.readlink("/proc/self/fd/" + str(fd))
        except OSError:
            pass

    if not verify:
        return filename

    # If verify = True, we compare st_dev and st_ino of file and fd.
    # This involves additional stat and fstat calls. So this is disabled
    # by default.
    if filename and fd:
        s_file = do_stat(filename)
        s_fd = do_fstat(fd)

        if s_file and s_fd:
            if (s_file.st_ino, s_file.st_dev) == (s_fd.st_ino, s_fd.st_dev):
                return filename

    return None


def static_var(varname, value):
    """Decorator function to create pseudo static variables."""
    def decorate(func):
        setattr(func, varname, value)
        return func
    return decorate

# Rate limit to emit log message once a second
_DO_LOG_RL_INTERVAL = 1.0


@static_var("counter", defaultdict(int))
@static_var("last_called", defaultdict(repeat(0.0).next))
def do_log_rl(msg, *args, **kwargs):
    """
    Rate limited logger.

    :param msg: String or message to be logged
    :param log_level: Possible values- error, warning, info, debug, critical
    """
    log_level = kwargs.get('log_level', "error")
    if log_level not in ("error", "warning", "info", "debug", "critical"):
        log_level = "error"

    do_log_rl.counter[msg] += 1  # Increment msg counter
    interval = time.time() - do_log_rl.last_called[msg]

    if interval >= _DO_LOG_RL_INTERVAL:
        # Prefix PID of process and message count to original log msg
        emit_msg = "[PID:" + str(os.getpid()) + "]" \
            + "[RateLimitedLog;Count:" + str(do_log_rl.counter[msg]) + "] " \
            + msg
        # log_level is a param for do_log_rl and not for logging.* methods
        try:
            del kwargs['log_level']
        except KeyError:
            pass

        getattr(logging, log_level)(emit_msg, *args, **kwargs)  # Emit msg
        do_log_rl.counter[msg] = 0  # Reset msg counter when message is emitted
        do_log_rl.last_called[msg] = time.time()  # Reset msg time