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Commit | Line | Data |
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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
8c1be37e | 2 | |
10c1b188 LP |
3 | #if HAVE_VALGRIND_MEMCHECK_H |
4 | #include <valgrind/memcheck.h> | |
5 | #endif | |
6 | ||
dccca82b | 7 | #include <errno.h> |
8c1be37e | 8 | #include <fcntl.h> |
f1443709 LP |
9 | #include <linux/blkpg.h> |
10 | #include <linux/fs.h> | |
8c1be37e | 11 | #include <linux/loop.h> |
441ec804 | 12 | #include <sys/file.h> |
8c1be37e | 13 | #include <sys/ioctl.h> |
f2d9213f | 14 | #include <unistd.h> |
8c1be37e | 15 | |
021bf175 LP |
16 | #include "sd-device.h" |
17 | ||
8c1be37e | 18 | #include "alloc-util.h" |
86c1c1f3 | 19 | #include "blockdev-util.h" |
021bf175 | 20 | #include "device-util.h" |
e8c7c4d9 | 21 | #include "env-util.h" |
b0a94268 | 22 | #include "errno-util.h" |
8c1be37e | 23 | #include "fd-util.h" |
f1443709 | 24 | #include "fileio.h" |
8c1be37e | 25 | #include "loop-util.h" |
86c1c1f3 | 26 | #include "missing_loop.h" |
f1443709 | 27 | #include "parse-util.h" |
b202ec20 | 28 | #include "random-util.h" |
3cc44114 | 29 | #include "stat-util.h" |
f1443709 | 30 | #include "stdio-util.h" |
f2d9213f | 31 | #include "string-util.h" |
021bf175 | 32 | #include "tmpfile-util.h" |
8c1be37e | 33 | |
e8af3bfd | 34 | static void cleanup_clear_loop_close(int *fd) { |
86c1c1f3 LP |
35 | if (*fd < 0) |
36 | return; | |
37 | ||
38 | (void) ioctl(*fd, LOOP_CLR_FD); | |
39 | (void) safe_close(*fd); | |
40 | } | |
41 | ||
021bf175 LP |
42 | static int loop_is_bound(int fd) { |
43 | struct loop_info64 info; | |
44 | ||
45 | assert(fd >= 0); | |
46 | ||
47 | if (ioctl(fd, LOOP_GET_STATUS64, &info) < 0) { | |
48 | if (errno == ENXIO) | |
49 | return false; /* not bound! */ | |
50 | ||
51 | return -errno; | |
52 | } | |
53 | ||
54 | return true; /* bound! */ | |
55 | } | |
56 | ||
31c75fcc LP |
57 | static int get_current_uevent_seqnum(uint64_t *ret) { |
58 | _cleanup_free_ char *p = NULL; | |
59 | int r; | |
60 | ||
61 | r = read_full_virtual_file("/sys/kernel/uevent_seqnum", &p, NULL); | |
62 | if (r < 0) | |
63 | return log_debug_errno(r, "Failed to read current uevent sequence number: %m"); | |
64 | ||
a145f8c0 | 65 | r = safe_atou64(strstrip(p), ret); |
31c75fcc LP |
66 | if (r < 0) |
67 | return log_debug_errno(r, "Failed to parse current uevent sequence number: %s", p); | |
68 | ||
69 | return 0; | |
70 | } | |
71 | ||
021bf175 LP |
72 | static int device_has_block_children(sd_device *d) { |
73 | _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL; | |
7ffc7f3f | 74 | const char *main_ss, *main_dt; |
021bf175 LP |
75 | sd_device *q; |
76 | int r; | |
77 | ||
78 | assert(d); | |
79 | ||
80 | /* Checks if the specified device currently has block device children (i.e. partition block | |
81 | * devices). */ | |
82 | ||
7ffc7f3f | 83 | r = sd_device_get_subsystem(d, &main_ss); |
021bf175 LP |
84 | if (r < 0) |
85 | return r; | |
86 | ||
7ffc7f3f LP |
87 | if (!streq(main_ss, "block")) |
88 | return -EINVAL; | |
89 | ||
90 | r = sd_device_get_devtype(d, &main_dt); | |
021bf175 LP |
91 | if (r < 0) |
92 | return r; | |
93 | ||
7ffc7f3f | 94 | if (!streq(main_dt, "disk")) /* Refuse invocation on partition block device, insist on "whole" device */ |
021bf175 LP |
95 | return -EINVAL; |
96 | ||
97 | r = sd_device_enumerator_new(&e); | |
98 | if (r < 0) | |
99 | return r; | |
100 | ||
101 | r = sd_device_enumerator_allow_uninitialized(e); | |
102 | if (r < 0) | |
103 | return r; | |
104 | ||
105 | r = sd_device_enumerator_add_match_parent(e, d); | |
106 | if (r < 0) | |
107 | return r; | |
108 | ||
109 | FOREACH_DEVICE(e, q) { | |
7ffc7f3f | 110 | const char *ss, *dt; |
021bf175 LP |
111 | |
112 | r = sd_device_get_subsystem(q, &ss); | |
7ffc7f3f LP |
113 | if (r < 0) { |
114 | log_device_debug_errno(q, r, "Failed to get subsystem of child, ignoring: %m"); | |
021bf175 | 115 | continue; |
7ffc7f3f | 116 | } |
021bf175 | 117 | |
7ffc7f3f LP |
118 | if (!streq(ss, "block")) { |
119 | log_device_debug(q, "Skipping child that is not a block device (subsystem=%s).", ss); | |
021bf175 | 120 | continue; |
7ffc7f3f | 121 | } |
021bf175 | 122 | |
7ffc7f3f LP |
123 | r = sd_device_get_devtype(q, &dt); |
124 | if (r < 0) { | |
125 | log_device_debug_errno(q, r, "Failed to get devtype of child, ignoring: %m"); | |
021bf175 | 126 | continue; |
7ffc7f3f | 127 | } |
021bf175 | 128 | |
7ffc7f3f LP |
129 | if (!streq(dt, "partition")) { |
130 | log_device_debug(q, "Skipping non-partition child (devtype=%s).", dt); | |
021bf175 | 131 | continue; |
7ffc7f3f | 132 | } |
021bf175 | 133 | |
7ffc7f3f | 134 | return true; /* we have block device children */ |
021bf175 LP |
135 | } |
136 | ||
7ffc7f3f | 137 | return false; |
021bf175 LP |
138 | } |
139 | ||
95c50092 LP |
140 | static int loop_configure( |
141 | int fd, | |
021bf175 | 142 | int nr, |
95c50092 | 143 | const struct loop_config *c, |
31c75fcc | 144 | bool *try_loop_configure, |
8ede1e86 LP |
145 | uint64_t *ret_seqnum_not_before, |
146 | usec_t *ret_timestamp_not_before) { | |
95c50092 | 147 | |
021bf175 LP |
148 | _cleanup_(sd_device_unrefp) sd_device *d = NULL; |
149 | _cleanup_free_ char *sysname = NULL; | |
738f29cb | 150 | _cleanup_close_ int lock_fd = -1; |
e8c7c4d9 | 151 | struct loop_info64 info_copy; |
31c75fcc | 152 | uint64_t seqnum; |
8ede1e86 | 153 | usec_t timestamp; |
86c1c1f3 LP |
154 | int r; |
155 | ||
156 | assert(fd >= 0); | |
021bf175 | 157 | assert(nr >= 0); |
86c1c1f3 | 158 | assert(c); |
95c50092 LP |
159 | assert(try_loop_configure); |
160 | ||
021bf175 LP |
161 | if (asprintf(&sysname, "loop%i", nr) < 0) |
162 | return -ENOMEM; | |
163 | ||
164 | r = sd_device_new_from_subsystem_sysname(&d, "block", sysname); | |
165 | if (r < 0) | |
166 | return r; | |
167 | ||
168 | /* Let's lock the device before we do anything. We take the BSD lock on a second, separately opened | |
169 | * fd for the device. udev after all watches for close() events (specifically IN_CLOSE_WRITE) on | |
170 | * block devices to reprobe them, hence by having a separate fd we will later close() we can ensure | |
171 | * we trigger udev after everything is done. If we'd lock our own fd instead and keep it open for a | |
172 | * long time udev would possibly never run on it again, even though the fd is unlocked, simply | |
173 | * because we never close() it. It also has the nice benefit we can use the _cleanup_close_ logic to | |
174 | * automatically release the lock, after we are done. */ | |
175 | lock_fd = fd_reopen(fd, O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY); | |
176 | if (lock_fd < 0) | |
177 | return lock_fd; | |
178 | if (flock(lock_fd, LOCK_EX) < 0) | |
179 | return -errno; | |
180 | ||
181 | /* Let's see if the device is really detached, i.e. currently has no associated partition block | |
182 | * devices. On various kernels (such as 5.8) it is possible to have a loopback block device that | |
183 | * superficially is detached but still has partition block devices associated for it. They only go | |
184 | * away when the device is reattached. (Yes, LOOP_CLR_FD doesn't work then, because officially | |
185 | * nothing is attached and LOOP_CTL_REMOVE doesn't either, since it doesn't care about partition | |
186 | * block devices. */ | |
187 | r = device_has_block_children(d); | |
188 | if (r < 0) | |
189 | return r; | |
190 | if (r > 0) { | |
191 | r = loop_is_bound(fd); | |
192 | if (r < 0) | |
193 | return r; | |
194 | if (r > 0) | |
195 | return -EBUSY; | |
196 | ||
197 | return -EUCLEAN; /* Bound but children? Tell caller to reattach something so that the | |
198 | * partition block devices are gone too. */ | |
199 | } | |
200 | ||
95c50092 | 201 | if (*try_loop_configure) { |
31c75fcc LP |
202 | /* Acquire uevent seqnum immediately before attaching the loopback device. This allows |
203 | * callers to ignore all uevents with a seqnum before this one, if they need to associate | |
204 | * uevent with this attachment. Doing so isn't race-free though, as uevents that happen in | |
205 | * the window between this reading of the seqnum, and the LOOP_CONFIGURE call might still be | |
206 | * mistaken as originating from our attachment, even though might be caused by an earlier | |
207 | * use. But doing this at least shortens the race window a bit. */ | |
208 | r = get_current_uevent_seqnum(&seqnum); | |
209 | if (r < 0) | |
210 | return r; | |
8ede1e86 | 211 | timestamp = now(CLOCK_MONOTONIC); |
31c75fcc | 212 | |
95c50092 LP |
213 | if (ioctl(fd, LOOP_CONFIGURE, c) < 0) { |
214 | /* Do fallback only if LOOP_CONFIGURE is not supported, propagate all other | |
215 | * errors. Note that the kernel is weird: non-existing ioctls currently return EINVAL | |
216 | * rather than ENOTTY on loopback block devices. They should fix that in the kernel, | |
217 | * but in the meantime we accept both here. */ | |
218 | if (!ERRNO_IS_NOT_SUPPORTED(errno) && errno != EINVAL) | |
219 | return -errno; | |
86c1c1f3 | 220 | |
95c50092 LP |
221 | *try_loop_configure = false; |
222 | } else { | |
223 | bool good = true; | |
224 | ||
225 | if (c->info.lo_sizelimit != 0) { | |
226 | /* Kernel 5.8 vanilla doesn't properly propagate the size limit into the | |
227 | * block device. If it's used, let's immediately check if it had the desired | |
228 | * effect hence. And if not use classic LOOP_SET_STATUS64. */ | |
229 | uint64_t z; | |
230 | ||
231 | if (ioctl(fd, BLKGETSIZE64, &z) < 0) { | |
232 | r = -errno; | |
233 | goto fail; | |
234 | } | |
235 | ||
236 | if (z != c->info.lo_sizelimit) { | |
237 | log_debug("LOOP_CONFIGURE is broken, doesn't honour .lo_sizelimit. Falling back to LOOP_SET_STATUS64."); | |
238 | good = false; | |
239 | } | |
bb2551bd | 240 | } |
86c1c1f3 | 241 | |
95c50092 LP |
242 | if (FLAGS_SET(c->info.lo_flags, LO_FLAGS_PARTSCAN)) { |
243 | /* Kernel 5.8 vanilla doesn't properly propagate the partition scanning flag | |
244 | * into the block device. Let's hence verify if things work correctly here | |
245 | * before returning. */ | |
246 | ||
247 | r = blockdev_partscan_enabled(fd); | |
248 | if (r < 0) | |
249 | goto fail; | |
250 | if (r == 0) { | |
251 | log_debug("LOOP_CONFIGURE is broken, doesn't honour LO_FLAGS_PARTSCAN. Falling back to LOOP_SET_STATUS64."); | |
252 | good = false; | |
253 | } | |
bb2551bd | 254 | } |
86c1c1f3 | 255 | |
95c50092 LP |
256 | if (!good) { |
257 | /* LOOP_CONFIGURE doesn't work. Remember that. */ | |
258 | *try_loop_configure = false; | |
259 | ||
260 | /* We return EBUSY here instead of retrying immediately with LOOP_SET_FD, | |
261 | * because LOOP_CLR_FD is async: if the operation cannot be executed right | |
262 | * away it just sets the autoclear flag on the device. This means there's a | |
263 | * good chance we cannot actually reuse the loopback device right-away. Hence | |
264 | * let's assume it's busy, avoid the trouble and let the calling loop call us | |
265 | * again with a new, likely unused device. */ | |
266 | r = -EBUSY; | |
bb2551bd | 267 | goto fail; |
bb2551bd | 268 | } |
bb2551bd | 269 | |
31c75fcc LP |
270 | if (ret_seqnum_not_before) |
271 | *ret_seqnum_not_before = seqnum; | |
8ede1e86 LP |
272 | if (ret_timestamp_not_before) |
273 | *ret_timestamp_not_before = timestamp; | |
31c75fcc | 274 | |
bb2551bd | 275 | return 0; |
95c50092 | 276 | } |
86c1c1f3 LP |
277 | } |
278 | ||
31c75fcc LP |
279 | /* Let's read the seqnum again, to shorten the window. */ |
280 | r = get_current_uevent_seqnum(&seqnum); | |
281 | if (r < 0) | |
282 | return r; | |
8ede1e86 | 283 | timestamp = now(CLOCK_MONOTONIC); |
31c75fcc | 284 | |
738f29cb LP |
285 | /* Since kernel commit 5db470e229e22b7eda6e23b5566e532c96fb5bc3 (kernel v5.0) the LOOP_SET_STATUS64 |
286 | * ioctl can return EAGAIN in case we change the lo_offset field, if someone else is accessing the | |
287 | * block device while we try to reconfigure it. This is a pretty common case, since udev might | |
288 | * instantly start probing the device as soon as we attach an fd to it. Hence handle it in two ways: | |
273d76f4 | 289 | * first, let's take the BSD lock to ensure that udev will not step in between the point in |
738f29cb LP |
290 | * time where we attach the fd and where we reconfigure the device. Secondly, let's wait 50ms on |
291 | * EAGAIN and retry. The former should be an efficient mechanism to avoid we have to wait 50ms | |
292 | * needlessly if we are just racing against udev. The latter is protection against all other cases, | |
021bf175 | 293 | * i.e. peers that do not take the BSD lock. */ |
738f29cb | 294 | |
86c1c1f3 LP |
295 | if (ioctl(fd, LOOP_SET_FD, c->fd) < 0) |
296 | return -errno; | |
297 | ||
e8c7c4d9 LP |
298 | /* Only some of the flags LOOP_CONFIGURE can set are also settable via LOOP_SET_STATUS64, hence mask |
299 | * them out. */ | |
300 | info_copy = c->info; | |
301 | info_copy.lo_flags &= LOOP_SET_STATUS_SETTABLE_FLAGS; | |
302 | ||
738f29cb | 303 | for (unsigned n_attempts = 0;;) { |
e8c7c4d9 | 304 | if (ioctl(fd, LOOP_SET_STATUS64, &info_copy) >= 0) |
738f29cb LP |
305 | break; |
306 | if (errno != EAGAIN || ++n_attempts >= 64) { | |
307 | r = log_debug_errno(errno, "Failed to configure loopback device: %m"); | |
308 | goto fail; | |
309 | } | |
310 | ||
b202ec20 LP |
311 | /* Sleep some random time, but at least 10ms, at most 250ms. Increase the delay the more |
312 | * failed attempts we see */ | |
313 | (void) usleep(UINT64_C(10) * USEC_PER_MSEC + | |
b0dbffd8 | 314 | random_u64_range(UINT64_C(240) * USEC_PER_MSEC * n_attempts/64)); |
e8af3bfd | 315 | } |
86c1c1f3 | 316 | |
b9a9748a LP |
317 | /* Work around a kernel bug, where changing offset/size of the loopback device doesn't correctly |
318 | * invalidate the buffer cache. For details see: | |
319 | * | |
320 | * https://android.googlesource.com/platform/system/apex/+/bef74542fbbb4cd629793f4efee8e0053b360570 | |
321 | * | |
322 | * This was fixed in kernel 5.0, see: | |
323 | * | |
324 | * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5db470e229e22b7eda6e23b5566e532c96fb5bc3 | |
325 | * | |
326 | * We'll run the work-around here in the legacy LOOP_SET_STATUS64 codepath. In the LOOP_CONFIGURE | |
327 | * codepath above it should not be necessary. */ | |
328 | if (c->info.lo_offset != 0 || c->info.lo_sizelimit != 0) | |
329 | if (ioctl(fd, BLKFLSBUF, 0) < 0) | |
330 | log_debug_errno(errno, "Failed to issue BLKFLSBUF ioctl, ignoring: %m"); | |
331 | ||
e8c7c4d9 LP |
332 | /* LO_FLAGS_DIRECT_IO is a flags we need to configure via explicit ioctls. */ |
333 | if (FLAGS_SET(c->info.lo_flags, LO_FLAGS_DIRECT_IO)) { | |
334 | unsigned long b = 1; | |
335 | ||
336 | if (ioctl(fd, LOOP_SET_DIRECT_IO, b) < 0) | |
337 | log_debug_errno(errno, "Failed to enable direct IO mode on loopback device /dev/loop%i, ignoring: %m", nr); | |
338 | } | |
339 | ||
31c75fcc LP |
340 | if (ret_seqnum_not_before) |
341 | *ret_seqnum_not_before = seqnum; | |
8ede1e86 LP |
342 | if (ret_timestamp_not_before) |
343 | *ret_timestamp_not_before = timestamp; | |
31c75fcc | 344 | |
86c1c1f3 LP |
345 | return 0; |
346 | ||
347 | fail: | |
348 | (void) ioctl(fd, LOOP_CLR_FD); | |
349 | return r; | |
e8af3bfd ZJS |
350 | } |
351 | ||
021bf175 LP |
352 | static int attach_empty_file(int loop, int nr) { |
353 | _cleanup_close_ int fd = -1; | |
354 | ||
355 | /* So here's the thing: on various kernels (5.8 at least) loop block devices might enter a state | |
356 | * where they are detached but nonetheless have partitions, when used heavily. Accessing these | |
357 | * partitions results in immediatey IO errors. There's no pretty way to get rid of them | |
358 | * again. Neither LOOP_CLR_FD nor LOOP_CTL_REMOVE suffice (see above). What does work is to | |
359 | * reassociate them with a new fd however. This is what we do here hence: we associate the devices | |
377a9545 | 360 | * with an empty file (i.e. an image that definitely has no partitions). We then immediately clear it |
021bf175 LP |
361 | * again. This suffices to make the partitions go away. Ugly but appears to work. */ |
362 | ||
363 | log_debug("Found unattached loopback block device /dev/loop%i with partitions. Attaching empty file to remove them.", nr); | |
364 | ||
365 | fd = open_tmpfile_unlinkable(NULL, O_RDONLY); | |
366 | if (fd < 0) | |
367 | return fd; | |
368 | ||
369 | if (flock(loop, LOCK_EX) < 0) | |
370 | return -errno; | |
371 | ||
372 | if (ioctl(loop, LOOP_SET_FD, fd) < 0) | |
373 | return -errno; | |
374 | ||
375 | if (ioctl(loop, LOOP_SET_STATUS64, &(struct loop_info64) { | |
376 | .lo_flags = LO_FLAGS_READ_ONLY| | |
377 | LO_FLAGS_AUTOCLEAR| | |
378 | LO_FLAGS_PARTSCAN, /* enable partscan, so that the partitions really go away */ | |
379 | }) < 0) | |
380 | return -errno; | |
381 | ||
382 | if (ioctl(loop, LOOP_CLR_FD) < 0) | |
383 | return -errno; | |
384 | ||
385 | /* The caller is expected to immediately close the loopback device after this, so that the BSD lock | |
386 | * is released, and udev sees the changes. */ | |
387 | return 0; | |
388 | } | |
389 | ||
e8c7c4d9 | 390 | static int loop_device_make_internal( |
ed9eeb7b LP |
391 | int fd, |
392 | int open_flags, | |
393 | uint64_t offset, | |
394 | uint64_t size, | |
395 | uint32_t loop_flags, | |
396 | LoopDevice **ret) { | |
8c1be37e | 397 | |
e8c7c4d9 | 398 | _cleanup_close_ int direct_io_fd = -1; |
8c1be37e | 399 | _cleanup_free_ char *loopdev = NULL; |
95c50092 | 400 | bool try_loop_configure = true; |
86c1c1f3 | 401 | struct loop_config config; |
50d04699 | 402 | LoopDevice *d = NULL; |
31c75fcc | 403 | uint64_t seqnum = UINT64_MAX; |
8ede1e86 | 404 | usec_t timestamp = USEC_INFINITY; |
e8c7c4d9 | 405 | int nr = -1, r, f_flags; |
8c1be37e | 406 | struct stat st; |
8c1be37e LP |
407 | |
408 | assert(fd >= 0); | |
409 | assert(ret); | |
410 | assert(IN_SET(open_flags, O_RDWR, O_RDONLY)); | |
411 | ||
412 | if (fstat(fd, &st) < 0) | |
413 | return -errno; | |
414 | ||
415 | if (S_ISBLK(st.st_mode)) { | |
86c1c1f3 | 416 | if (ioctl(fd, LOOP_GET_STATUS64, &config.info) >= 0) { |
b26c39ad | 417 | /* Oh! This is a loopback device? That's interesting! */ |
10c1b188 LP |
418 | |
419 | #if HAVE_VALGRIND_MEMCHECK_H | |
420 | /* Valgrind currently doesn't know LOOP_GET_STATUS64. Remove this once it does */ | |
86c1c1f3 | 421 | VALGRIND_MAKE_MEM_DEFINED(&config.info, sizeof(config.info)); |
10c1b188 | 422 | #endif |
86c1c1f3 | 423 | nr = config.info.lo_number; |
b26c39ad LP |
424 | |
425 | if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) | |
426 | return -ENOMEM; | |
427 | } | |
428 | ||
ed9eeb7b | 429 | if (offset == 0 && IN_SET(size, 0, UINT64_MAX)) { |
ba5450f4 | 430 | _cleanup_close_ int copy = -1; |
bcef1743 | 431 | uint64_t diskseq = 0; |
8c1be37e | 432 | |
d7654742 LP |
433 | /* If this is already a block device and we are supposed to cover the whole of it |
434 | * then store an fd to the original open device node — and do not actually create an | |
435 | * unnecessary loopback device for it. Note that we reopen the inode here, instead of | |
436 | * keeping just a dup() clone of it around, since we want to ensure that the O_DIRECT | |
437 | * flag of the handle we keep is off, we have our own file index, and have the right | |
438 | * read/write mode in effect. */ | |
439 | ||
440 | copy = fd_reopen(fd, open_flags|O_NONBLOCK|O_CLOEXEC|O_NOCTTY); | |
ed9eeb7b | 441 | if (copy < 0) |
d7654742 | 442 | return copy; |
8c1be37e | 443 | |
7e93a658 | 444 | r = fd_get_diskseq(copy, &diskseq); |
bcef1743 LB |
445 | if (r < 0 && r != -EOPNOTSUPP) |
446 | return r; | |
447 | ||
ed9eeb7b LP |
448 | d = new(LoopDevice, 1); |
449 | if (!d) | |
450 | return -ENOMEM; | |
ed9eeb7b | 451 | *d = (LoopDevice) { |
ba5450f4 | 452 | .fd = TAKE_FD(copy), |
b26c39ad LP |
453 | .nr = nr, |
454 | .node = TAKE_PTR(loopdev), | |
ed9eeb7b | 455 | .relinquished = true, /* It's not allocated by us, don't destroy it when this object is freed */ |
f3859d5f | 456 | .devno = st.st_rdev, |
bcef1743 | 457 | .diskseq = diskseq, |
31c75fcc | 458 | .uevent_seqnum_not_before = UINT64_MAX, |
8ede1e86 | 459 | .timestamp_not_before = USEC_INFINITY, |
ed9eeb7b LP |
460 | }; |
461 | ||
462 | *ret = d; | |
463 | return d->fd; | |
464 | } | |
465 | } else { | |
466 | r = stat_verify_regular(&st); | |
467 | if (r < 0) | |
468 | return r; | |
8c1be37e LP |
469 | } |
470 | ||
e8c7c4d9 LP |
471 | f_flags = fcntl(fd, F_GETFL); |
472 | if (f_flags < 0) | |
473 | return -errno; | |
474 | ||
475 | if (FLAGS_SET(loop_flags, LO_FLAGS_DIRECT_IO) != FLAGS_SET(f_flags, O_DIRECT)) { | |
476 | /* If LO_FLAGS_DIRECT_IO is requested, then make sure we have the fd open with O_DIRECT, as | |
477 | * that's required. Conversely, if it's off require that O_DIRECT is off too (that's because | |
478 | * new kernels will implicitly enable LO_FLAGS_DIRECT_IO if O_DIRECT is set). | |
479 | * | |
480 | * Our intention here is that LO_FLAGS_DIRECT_IO is the primary knob, and O_DIRECT derived | |
481 | * from that automatically. */ | |
482 | ||
483 | direct_io_fd = fd_reopen(fd, (FLAGS_SET(loop_flags, LO_FLAGS_DIRECT_IO) ? O_DIRECT : 0)|O_CLOEXEC|O_NONBLOCK|open_flags); | |
484 | if (direct_io_fd < 0) { | |
485 | if (!FLAGS_SET(loop_flags, LO_FLAGS_DIRECT_IO)) | |
486 | return log_debug_errno(errno, "Failed to reopen file descriptor without O_DIRECT: %m"); | |
487 | ||
488 | /* Some file systems might not support O_DIRECT, let's gracefully continue without it then. */ | |
489 | log_debug_errno(errno, "Failed to enable O_DIRECT for backing file descriptor for loopback device. Continuing without."); | |
490 | loop_flags &= ~LO_FLAGS_DIRECT_IO; | |
491 | } else | |
492 | fd = direct_io_fd; /* From now on, operate on our new O_DIRECT fd */ | |
493 | } | |
494 | ||
e8af3bfd ZJS |
495 | _cleanup_close_ int control = -1; |
496 | _cleanup_(cleanup_clear_loop_close) int loop_with_fd = -1; | |
497 | ||
8c1be37e LP |
498 | control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); |
499 | if (control < 0) | |
500 | return -errno; | |
501 | ||
86c1c1f3 LP |
502 | config = (struct loop_config) { |
503 | .fd = fd, | |
504 | .info = { | |
505 | /* Use the specified flags, but configure the read-only flag from the open flags, and force autoclear */ | |
0950526a | 506 | .lo_flags = (loop_flags & ~LO_FLAGS_READ_ONLY) | ((open_flags & O_ACCMODE) == O_RDONLY ? LO_FLAGS_READ_ONLY : 0) | LO_FLAGS_AUTOCLEAR, |
86c1c1f3 LP |
507 | .lo_offset = offset, |
508 | .lo_sizelimit = size == UINT64_MAX ? 0 : size, | |
509 | }, | |
510 | }; | |
511 | ||
0f6519d4 LP |
512 | /* Loop around LOOP_CTL_GET_FREE, since at the moment we attempt to open the returned device it might |
513 | * be gone already, taken by somebody else racing against us. */ | |
e8af3bfd ZJS |
514 | for (unsigned n_attempts = 0;;) { |
515 | _cleanup_close_ int loop = -1; | |
516 | ||
cc530466 LP |
517 | /* Let's take a lock on the control device first. On a busy system, where many programs |
518 | * attempt to allocate a loopback device at the same time, we might otherwise keep looping | |
519 | * around relatively heavy operations: asking for a free loopback device, then opening it, | |
520 | * validating it, attaching something to it. Let's serialize this whole operation, to make | |
521 | * unnecessary busywork less likely. Note that this is just something we do to optimize our | |
522 | * own code (and whoever else decides to use LOCK_EX locks for this), taking this lock is not | |
523 | * necessary, it just means it's less likely we have to iterate through this loop again and | |
524 | * again if our own code races against our own code. */ | |
525 | if (flock(control, LOCK_EX) < 0) | |
526 | return -errno; | |
527 | ||
0f6519d4 LP |
528 | nr = ioctl(control, LOOP_CTL_GET_FREE); |
529 | if (nr < 0) | |
530 | return -errno; | |
8c1be37e | 531 | |
0f6519d4 LP |
532 | if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) |
533 | return -ENOMEM; | |
8c1be37e | 534 | |
0f6519d4 | 535 | loop = open(loopdev, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|open_flags); |
01813148 ZJS |
536 | if (loop < 0) { |
537 | /* Somebody might've gotten the same number from the kernel, used the device, | |
538 | * and called LOOP_CTL_REMOVE on it. Let's retry with a new number. */ | |
49043f81 | 539 | if (!ERRNO_IS_DEVICE_ABSENT(errno)) |
01813148 ZJS |
540 | return -errno; |
541 | } else { | |
8ede1e86 | 542 | r = loop_configure(loop, nr, &config, &try_loop_configure, &seqnum, ×tamp); |
86c1c1f3 | 543 | if (r >= 0) { |
01813148 ZJS |
544 | loop_with_fd = TAKE_FD(loop); |
545 | break; | |
546 | } | |
021bf175 LP |
547 | if (r == -EUCLEAN) { |
548 | /* Make left-over partition disappear hack (see above) */ | |
549 | r = attach_empty_file(loop, nr); | |
550 | if (r < 0 && r != -EBUSY) | |
551 | return r; | |
552 | } else if (r != -EBUSY) | |
86c1c1f3 | 553 | return r; |
e8af3bfd | 554 | } |
01813148 | 555 | |
cc530466 LP |
556 | /* OK, this didn't work, let's try again a bit later, but first release the lock on the |
557 | * control device */ | |
558 | if (flock(control, LOCK_UN) < 0) | |
559 | return -errno; | |
560 | ||
e8af3bfd ZJS |
561 | if (++n_attempts >= 64) /* Give up eventually */ |
562 | return -EBUSY; | |
0f6519d4 | 563 | |
3e921057 LP |
564 | /* Now close the loop device explicitly. This will release any lock acquired by |
565 | * attach_empty_file() or similar, while we sleep below. */ | |
566 | loop = safe_close(loop); | |
0f6519d4 | 567 | loopdev = mfree(loopdev); |
b202ec20 LP |
568 | |
569 | /* Wait some random time, to make collision less likely. Let's pick a random time in the | |
570 | * range 0ms…250ms, linearly scaled by the number of failed attempts. */ | |
b0dbffd8 LP |
571 | (void) usleep(random_u64_range(UINT64_C(10) * USEC_PER_MSEC + |
572 | UINT64_C(240) * USEC_PER_MSEC * n_attempts/64)); | |
0f6519d4 | 573 | } |
8c1be37e | 574 | |
e8c7c4d9 LP |
575 | if (FLAGS_SET(loop_flags, LO_FLAGS_DIRECT_IO)) { |
576 | struct loop_info64 info; | |
577 | ||
578 | if (ioctl(loop_with_fd, LOOP_GET_STATUS64, &info) < 0) | |
579 | return -errno; | |
580 | ||
581 | #if HAVE_VALGRIND_MEMCHECK_H | |
582 | VALGRIND_MAKE_MEM_DEFINED(&info, sizeof(info)); | |
583 | #endif | |
584 | ||
585 | /* On older kernels (<= 5.3) it was necessary to set the block size of the loopback block | |
586 | * device to the logical block size of the underlying file system. Since there was no nice | |
587 | * way to query the value, we are not bothering to do this however. On newer kernels the | |
588 | * block size is propagated automatically and does not require intervention from us. We'll | |
589 | * check here if enabling direct IO worked, to make this easily debuggable however. | |
590 | * | |
591 | * (Should anyone really care and actually wants direct IO on old kernels: it might be worth | |
592 | * enabling direct IO with iteratively larger block sizes until it eventually works.) */ | |
593 | if (!FLAGS_SET(info.lo_flags, LO_FLAGS_DIRECT_IO)) | |
594 | log_debug("Could not enable direct IO mode, proceeding in buffered IO mode."); | |
595 | } | |
596 | ||
f3859d5f LP |
597 | if (fstat(loop_with_fd, &st) < 0) |
598 | return -errno; | |
599 | assert(S_ISBLK(st.st_mode)); | |
600 | ||
bcef1743 | 601 | uint64_t diskseq = 0; |
7e93a658 | 602 | r = fd_get_diskseq(loop_with_fd, &diskseq); |
bcef1743 LB |
603 | if (r < 0 && r != -EOPNOTSUPP) |
604 | return r; | |
605 | ||
8c1be37e | 606 | d = new(LoopDevice, 1); |
e8af3bfd ZJS |
607 | if (!d) |
608 | return -ENOMEM; | |
8c1be37e | 609 | *d = (LoopDevice) { |
e8af3bfd | 610 | .fd = TAKE_FD(loop_with_fd), |
1cc6c93a | 611 | .node = TAKE_PTR(loopdev), |
8c1be37e | 612 | .nr = nr, |
f3859d5f | 613 | .devno = st.st_rdev, |
bcef1743 | 614 | .diskseq = diskseq, |
31c75fcc | 615 | .uevent_seqnum_not_before = seqnum, |
8ede1e86 | 616 | .timestamp_not_before = timestamp, |
8c1be37e LP |
617 | }; |
618 | ||
3b195f63 LP |
619 | log_debug("Successfully acquired %s, devno=%u:%u, nr=%i, diskseq=%" PRIu64, |
620 | d->node, | |
621 | major(d->devno), minor(d->devno), | |
622 | d->nr, | |
623 | d->diskseq); | |
624 | ||
8c1be37e | 625 | *ret = d; |
38bd449f | 626 | return d->fd; |
8c1be37e LP |
627 | } |
628 | ||
e8c7c4d9 LP |
629 | static uint32_t loop_flags_mangle(uint32_t loop_flags) { |
630 | int r; | |
631 | ||
632 | r = getenv_bool("SYSTEMD_LOOP_DIRECT_IO"); | |
633 | if (r < 0 && r != -ENXIO) | |
634 | log_debug_errno(r, "Failed to parse $SYSTEMD_LOOP_DIRECT_IO, ignoring: %m"); | |
635 | ||
bfd08445 | 636 | return UPDATE_FLAG(loop_flags, LO_FLAGS_DIRECT_IO, r != 0); /* Turn on LO_FLAGS_DIRECT_IO by default, unless explicitly configured to off. */ |
e8c7c4d9 LP |
637 | } |
638 | ||
639 | int loop_device_make( | |
640 | int fd, | |
641 | int open_flags, | |
642 | uint64_t offset, | |
643 | uint64_t size, | |
644 | uint32_t loop_flags, | |
645 | LoopDevice **ret) { | |
646 | ||
647 | assert(fd >= 0); | |
648 | assert(ret); | |
e8c7c4d9 LP |
649 | |
650 | return loop_device_make_internal( | |
651 | fd, | |
652 | open_flags, | |
653 | offset, | |
654 | size, | |
bfd08445 | 655 | loop_flags_mangle(loop_flags), |
e8c7c4d9 LP |
656 | ret); |
657 | } | |
658 | ||
79e8393a LP |
659 | int loop_device_make_by_path( |
660 | const char *path, | |
661 | int open_flags, | |
662 | uint32_t loop_flags, | |
663 | LoopDevice **ret) { | |
664 | ||
e8c7c4d9 | 665 | int r, basic_flags, direct_flags, rdwr_flags; |
8c1be37e | 666 | _cleanup_close_ int fd = -1; |
aa4d3aa3 | 667 | bool direct = false; |
8c1be37e LP |
668 | |
669 | assert(path); | |
670 | assert(ret); | |
b0a94268 | 671 | assert(open_flags < 0 || IN_SET(open_flags, O_RDWR, O_RDONLY)); |
8c1be37e | 672 | |
b0a94268 LP |
673 | /* Passing < 0 as open_flags here means we'll try to open the device writable if we can, retrying |
674 | * read-only if we cannot. */ | |
675 | ||
e8c7c4d9 LP |
676 | loop_flags = loop_flags_mangle(loop_flags); |
677 | ||
678 | /* Let's open with O_DIRECT if we can. But not all file systems support that, hence fall back to | |
679 | * non-O_DIRECT mode automatically, if it fails. */ | |
680 | ||
681 | basic_flags = O_CLOEXEC|O_NONBLOCK|O_NOCTTY; | |
682 | direct_flags = FLAGS_SET(loop_flags, LO_FLAGS_DIRECT_IO) ? O_DIRECT : 0; | |
683 | rdwr_flags = open_flags >= 0 ? open_flags : O_RDWR; | |
684 | ||
685 | fd = open(path, basic_flags|direct_flags|rdwr_flags); | |
686 | if (fd < 0 && direct_flags != 0) /* If we had O_DIRECT on, and things failed with that, let's immediately try again without */ | |
687 | fd = open(path, basic_flags|rdwr_flags); | |
aa4d3aa3 LP |
688 | else |
689 | direct = direct_flags != 0; | |
b0a94268 LP |
690 | if (fd < 0) { |
691 | r = -errno; | |
692 | ||
693 | /* Retry read-only? */ | |
694 | if (open_flags >= 0 || !(ERRNO_IS_PRIVILEGE(r) || r == -EROFS)) | |
695 | return r; | |
696 | ||
e8c7c4d9 LP |
697 | fd = open(path, basic_flags|direct_flags|O_RDONLY); |
698 | if (fd < 0 && direct_flags != 0) /* as above */ | |
699 | fd = open(path, basic_flags|O_RDONLY); | |
aa4d3aa3 LP |
700 | else |
701 | direct = direct_flags != 0; | |
b0a94268 LP |
702 | if (fd < 0) |
703 | return r; /* Propagate original error */ | |
704 | ||
705 | open_flags = O_RDONLY; | |
706 | } else if (open_flags < 0) | |
707 | open_flags = O_RDWR; | |
8c1be37e | 708 | |
aa4d3aa3 LP |
709 | log_debug("Opened '%s' in %s access mode%s, with O_DIRECT %s%s.", |
710 | path, | |
711 | open_flags == O_RDWR ? "O_RDWR" : "O_RDONLY", | |
712 | open_flags != rdwr_flags ? " (O_RDWR was requested but not allowed)" : "", | |
713 | direct ? "enabled" : "disabled", | |
714 | direct != (direct_flags != 0) ? " (O_DIRECT was requested but not supported)" : ""); | |
715 | ||
0193b93e | 716 | return loop_device_make_internal(fd, open_flags, 0, 0, loop_flags, ret); |
8c1be37e LP |
717 | } |
718 | ||
719 | LoopDevice* loop_device_unref(LoopDevice *d) { | |
720 | if (!d) | |
721 | return NULL; | |
722 | ||
723 | if (d->fd >= 0) { | |
cae1e8fb LP |
724 | /* Implicitly sync the device, since otherwise in-flight blocks might not get written */ |
725 | if (fsync(d->fd) < 0) | |
726 | log_debug_errno(errno, "Failed to sync loop block device, ignoring: %m"); | |
727 | ||
a2ea3b2f | 728 | if (d->nr >= 0 && !d->relinquished) { |
8c1be37e LP |
729 | if (ioctl(d->fd, LOOP_CLR_FD) < 0) |
730 | log_debug_errno(errno, "Failed to clear loop device: %m"); | |
731 | ||
732 | } | |
733 | ||
734 | safe_close(d->fd); | |
735 | } | |
736 | ||
a2ea3b2f | 737 | if (d->nr >= 0 && !d->relinquished) { |
8c1be37e LP |
738 | _cleanup_close_ int control = -1; |
739 | ||
740 | control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); | |
741 | if (control < 0) | |
f2d9213f ZJS |
742 | log_warning_errno(errno, |
743 | "Failed to open loop control device, cannot remove loop device %s: %m", | |
744 | strna(d->node)); | |
745 | else | |
746 | for (unsigned n_attempts = 0;;) { | |
747 | if (ioctl(control, LOOP_CTL_REMOVE, d->nr) >= 0) | |
748 | break; | |
749 | if (errno != EBUSY || ++n_attempts >= 64) { | |
750 | log_warning_errno(errno, "Failed to remove device %s: %m", strna(d->node)); | |
751 | break; | |
752 | } | |
cae1e8fb | 753 | (void) usleep(50 * USEC_PER_MSEC); |
f2d9213f | 754 | } |
8c1be37e LP |
755 | } |
756 | ||
757 | free(d->node); | |
5fecf46d | 758 | return mfree(d); |
8c1be37e | 759 | } |
a2ea3b2f LP |
760 | |
761 | void loop_device_relinquish(LoopDevice *d) { | |
762 | assert(d); | |
763 | ||
764 | /* Don't attempt to clean up the loop device anymore from this point on. Leave the clean-ing up to the kernel | |
765 | * itself, using the loop device "auto-clear" logic we already turned on when creating the device. */ | |
766 | ||
767 | d->relinquished = true; | |
768 | } | |
9dabc4fd LP |
769 | |
770 | int loop_device_open(const char *loop_path, int open_flags, LoopDevice **ret) { | |
771 | _cleanup_close_ int loop_fd = -1; | |
772 | _cleanup_free_ char *p = NULL; | |
b26c39ad | 773 | struct loop_info64 info; |
9dabc4fd LP |
774 | struct stat st; |
775 | LoopDevice *d; | |
b26c39ad | 776 | int nr; |
9dabc4fd LP |
777 | |
778 | assert(loop_path); | |
e8c7c4d9 | 779 | assert(IN_SET(open_flags, O_RDWR, O_RDONLY)); |
9dabc4fd LP |
780 | assert(ret); |
781 | ||
782 | loop_fd = open(loop_path, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|open_flags); | |
783 | if (loop_fd < 0) | |
784 | return -errno; | |
785 | ||
786 | if (fstat(loop_fd, &st) < 0) | |
787 | return -errno; | |
9dabc4fd LP |
788 | if (!S_ISBLK(st.st_mode)) |
789 | return -ENOTBLK; | |
790 | ||
10c1b188 LP |
791 | if (ioctl(loop_fd, LOOP_GET_STATUS64, &info) >= 0) { |
792 | #if HAVE_VALGRIND_MEMCHECK_H | |
793 | /* Valgrind currently doesn't know LOOP_GET_STATUS64. Remove this once it does */ | |
794 | VALGRIND_MAKE_MEM_DEFINED(&info, sizeof(info)); | |
795 | #endif | |
b26c39ad | 796 | nr = info.lo_number; |
10c1b188 | 797 | } else |
b26c39ad LP |
798 | nr = -1; |
799 | ||
9dabc4fd LP |
800 | p = strdup(loop_path); |
801 | if (!p) | |
802 | return -ENOMEM; | |
803 | ||
804 | d = new(LoopDevice, 1); | |
805 | if (!d) | |
806 | return -ENOMEM; | |
807 | ||
808 | *d = (LoopDevice) { | |
809 | .fd = TAKE_FD(loop_fd), | |
b26c39ad | 810 | .nr = nr, |
9dabc4fd LP |
811 | .node = TAKE_PTR(p), |
812 | .relinquished = true, /* It's not ours, don't try to destroy it when this object is freed */ | |
79e8393a | 813 | .devno = st.st_dev, |
31c75fcc | 814 | .uevent_seqnum_not_before = UINT64_MAX, |
8ede1e86 | 815 | .timestamp_not_before = USEC_INFINITY, |
9dabc4fd LP |
816 | }; |
817 | ||
818 | *ret = d; | |
819 | return d->fd; | |
820 | } | |
821 | ||
f1443709 LP |
822 | static int resize_partition(int partition_fd, uint64_t offset, uint64_t size) { |
823 | char sysfs[STRLEN("/sys/dev/block/:/partition") + 2*DECIMAL_STR_MAX(dev_t) + 1]; | |
824 | _cleanup_free_ char *whole = NULL, *buffer = NULL; | |
825 | uint64_t current_offset, current_size, partno; | |
826 | _cleanup_close_ int whole_fd = -1; | |
827 | struct stat st; | |
828 | dev_t devno; | |
829 | int r; | |
830 | ||
831 | assert(partition_fd >= 0); | |
832 | ||
833 | /* Resizes the partition the loopback device refer to (assuming it refers to one instead of an actual | |
834 | * loopback device), and changes the offset, if needed. This is a fancy wrapper around | |
835 | * BLKPG_RESIZE_PARTITION. */ | |
836 | ||
837 | if (fstat(partition_fd, &st) < 0) | |
838 | return -errno; | |
839 | ||
840 | assert(S_ISBLK(st.st_mode)); | |
841 | ||
842 | xsprintf(sysfs, "/sys/dev/block/%u:%u/partition", major(st.st_rdev), minor(st.st_rdev)); | |
843 | r = read_one_line_file(sysfs, &buffer); | |
844 | if (r == -ENOENT) /* not a partition, cannot resize */ | |
845 | return -ENOTTY; | |
846 | if (r < 0) | |
847 | return r; | |
848 | r = safe_atou64(buffer, &partno); | |
849 | if (r < 0) | |
850 | return r; | |
851 | ||
852 | xsprintf(sysfs, "/sys/dev/block/%u:%u/start", major(st.st_rdev), minor(st.st_rdev)); | |
853 | ||
854 | buffer = mfree(buffer); | |
855 | r = read_one_line_file(sysfs, &buffer); | |
856 | if (r < 0) | |
857 | return r; | |
858 | r = safe_atou64(buffer, ¤t_offset); | |
859 | if (r < 0) | |
860 | return r; | |
861 | if (current_offset > UINT64_MAX/512U) | |
862 | return -EINVAL; | |
863 | current_offset *= 512U; | |
864 | ||
865 | if (ioctl(partition_fd, BLKGETSIZE64, ¤t_size) < 0) | |
866 | return -EINVAL; | |
867 | ||
868 | if (size == UINT64_MAX && offset == UINT64_MAX) | |
869 | return 0; | |
870 | if (current_size == size && current_offset == offset) | |
871 | return 0; | |
872 | ||
873 | xsprintf(sysfs, "/sys/dev/block/%u:%u/../dev", major(st.st_rdev), minor(st.st_rdev)); | |
874 | ||
875 | buffer = mfree(buffer); | |
876 | r = read_one_line_file(sysfs, &buffer); | |
877 | if (r < 0) | |
878 | return r; | |
879 | r = parse_dev(buffer, &devno); | |
880 | if (r < 0) | |
881 | return r; | |
882 | ||
883 | r = device_path_make_major_minor(S_IFBLK, devno, &whole); | |
884 | if (r < 0) | |
885 | return r; | |
886 | ||
887 | whole_fd = open(whole, O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY); | |
888 | if (whole_fd < 0) | |
889 | return -errno; | |
890 | ||
891 | struct blkpg_partition bp = { | |
892 | .pno = partno, | |
893 | .start = offset == UINT64_MAX ? current_offset : offset, | |
894 | .length = size == UINT64_MAX ? current_size : size, | |
895 | }; | |
896 | ||
897 | struct blkpg_ioctl_arg ba = { | |
898 | .op = BLKPG_RESIZE_PARTITION, | |
899 | .data = &bp, | |
900 | .datalen = sizeof(bp), | |
901 | }; | |
902 | ||
7c248223 | 903 | return RET_NERRNO(ioctl(whole_fd, BLKPG, &ba)); |
f1443709 LP |
904 | } |
905 | ||
c37878fc LP |
906 | int loop_device_refresh_size(LoopDevice *d, uint64_t offset, uint64_t size) { |
907 | struct loop_info64 info; | |
9dabc4fd LP |
908 | assert(d); |
909 | ||
f1443709 LP |
910 | /* Changes the offset/start of the loop device relative to the beginning of the underlying file or |
911 | * block device. If this loop device actually refers to a partition and not a loopback device, we'll | |
912 | * try to adjust the partition offsets instead. | |
913 | * | |
914 | * If either offset or size is UINT64_MAX we won't change that parameter. */ | |
915 | ||
9dabc4fd LP |
916 | if (d->fd < 0) |
917 | return -EBADF; | |
918 | ||
f1443709 LP |
919 | if (d->nr < 0) /* not a loopback device */ |
920 | return resize_partition(d->fd, offset, size); | |
921 | ||
c37878fc LP |
922 | if (ioctl(d->fd, LOOP_GET_STATUS64, &info) < 0) |
923 | return -errno; | |
924 | ||
10c1b188 LP |
925 | #if HAVE_VALGRIND_MEMCHECK_H |
926 | /* Valgrind currently doesn't know LOOP_GET_STATUS64. Remove this once it does */ | |
927 | VALGRIND_MAKE_MEM_DEFINED(&info, sizeof(info)); | |
928 | #endif | |
929 | ||
c37878fc LP |
930 | if (size == UINT64_MAX && offset == UINT64_MAX) |
931 | return 0; | |
932 | if (info.lo_sizelimit == size && info.lo_offset == offset) | |
933 | return 0; | |
934 | ||
935 | if (size != UINT64_MAX) | |
936 | info.lo_sizelimit = size; | |
937 | if (offset != UINT64_MAX) | |
938 | info.lo_offset = offset; | |
939 | ||
7c248223 | 940 | return RET_NERRNO(ioctl(d->fd, LOOP_SET_STATUS64, &info)); |
9dabc4fd | 941 | } |
441ec804 LP |
942 | |
943 | int loop_device_flock(LoopDevice *d, int operation) { | |
944 | assert(d); | |
945 | ||
946 | if (d->fd < 0) | |
947 | return -EBADF; | |
948 | ||
7c248223 | 949 | return RET_NERRNO(flock(d->fd, operation)); |
441ec804 | 950 | } |
8dbc208c LP |
951 | |
952 | int loop_device_sync(LoopDevice *d) { | |
953 | assert(d); | |
954 | ||
955 | /* We also do this implicitly in loop_device_unref(). Doing this explicitly here has the benefit that | |
956 | * we can check the return value though. */ | |
957 | ||
958 | if (d->fd < 0) | |
959 | return -EBADF; | |
960 | ||
7c248223 | 961 | return RET_NERRNO(fsync(d->fd)); |
8dbc208c | 962 | } |