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loop-util: save the flag about if LOOP_CONFIGURE ioctl works or not in loop_configure()

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When LOOP_CONFIGURE fail, then it is not necessary to call it on any
later call of loop_configure(). Let's save the flag in a static variable
in the function.
This commit is contained in:
Yu Watanabe
2022-09-09 04:31:10 +09:00
parent 54ba7daf23
commit bb273a5145
1 changed files with 18 additions and 20 deletions
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src/shared/loop-util.c
+18 -20
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@@ -221,11 +221,12 @@ static int loop_configure(
int fd,
int nr,
const struct loop_config *c,
bool *try_loop_configure,
uint64_t *ret_seqnum_not_before,
usec_t *ret_timestamp_not_before,
int *ret_lock_fd) {
static bool loop_configure_broken = false;
_cleanup_close_ int lock_fd = -1;
uint64_t seqnum;
usec_t timestamp;
@@ -234,7 +235,6 @@ static int loop_configure(
assert(fd >= 0);
assert(nr >= 0);
assert(c);
assert(try_loop_configure);
/* Let's lock the device before we do anything. We take the BSD lock on a second, separately opened
* fd for the device. udev after all watches for close() events (specifically IN_CLOSE_WRITE) on
@@ -272,7 +272,7 @@ static int loop_configure(
return -EUCLEAN;
}
if (*try_loop_configure) {
if (!loop_configure_broken) {
/* Acquire uevent seqnum immediately before attaching the loopback device. This allows
* callers to ignore all uevents with a seqnum before this one, if they need to associate
* uevent with this attachment. Doing so isn't race-free though, as uevents that happen in
@@ -293,14 +293,14 @@ static int loop_configure(
if (!ERRNO_IS_NOT_SUPPORTED(errno) && errno != EINVAL)
return -errno;
*try_loop_configure = false;
loop_configure_broken = true;
} else {
r = loop_configure_verify(fd, c);
if (r < 0)
goto fail;
if (r == 0) {
/* LOOP_CONFIGURE doesn't work. Remember that. */
*try_loop_configure = false;
loop_configure_broken = true;
/* We return EBUSY here instead of retrying immediately with LOOP_SET_FD,
* because LOOP_CLR_FD is async: if the operation cannot be executed right
@@ -311,26 +311,25 @@ static int loop_configure(
r = -EBUSY;
goto fail;
}
goto success;
}
}
/* Let's read the seqnum again, to shorten the window. */
r = get_current_uevent_seqnum(&seqnum);
if (r < 0)
return r;
if (loop_configure_broken) {
/* Let's read the seqnum again, to shorten the window. */
r = get_current_uevent_seqnum(&seqnum);
if (r < 0)
return r;
timestamp = now(CLOCK_MONOTONIC);
timestamp = now(CLOCK_MONOTONIC);
if (ioctl(fd, LOOP_SET_FD, c->fd) < 0)
return -errno;
if (ioctl(fd, LOOP_SET_FD, c->fd) < 0)
return -errno;
r = loop_configure_fallback(fd, c);
if (r < 0)
goto fail;
r = loop_configure_fallback(fd, c);
if (r < 0)
goto fail;
}
success:
if (ret_seqnum_not_before)
*ret_seqnum_not_before = seqnum;
if (ret_timestamp_not_before)
@@ -361,7 +360,6 @@ static int loop_device_make_internal(
_cleanup_(sd_device_unrefp) sd_device *dev = NULL;
_cleanup_close_ int direct_io_fd = -1;
_cleanup_free_ char *node = NULL, *backing_file = NULL;
bool try_loop_configure = true;
struct loop_config config;
LoopDevice *d;
uint64_t seqnum = UINT64_MAX;
@@ -482,7 +480,7 @@ static int loop_device_make_internal(
if (!ERRNO_IS_DEVICE_ABSENT(errno))
return -errno;
} else {
r = loop_configure(dev, loop, nr, &config, &try_loop_configure, &seqnum, &timestamp, &lock_fd);
r = loop_configure(dev, loop, nr, &config, &seqnum, &timestamp, &lock_fd);
if (r >= 0) {
loop_with_fd = TAKE_FD(loop);
break;