There is still a race risk: Device scheduled to detach is found by
loopcxt_find_by_backing_file(), but released before loopcxt_set_status() is
called, causing error on subsequent calls. To prevent error, retry it once
again.
Signed-off-by: Stanislav Brabec <sbrabec@xxxxxxx>
---
sys-utils/losetup.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/sys-utils/losetup.c b/sys-utils/losetup.c
index ba096fe..b156ab6 100644
--- a/sys-utils/losetup.c
+++ b/sys-utils/losetup.c
@@ -680,13 +680,20 @@ int main(int argc, char **argv)
switch (act) {
case A_CREATE:
{
+ /* If it is a device scheduled for detach, it can be detached
+ * just in middle of processing. Retry once, if it happens
+ * again, exit. */
+ int retries_left = 1;
int hasdev = loopcxt_has_device(&lc);
if (!hasdev && !force) {
+ retry:
res = loopcxt_find_by_backing_file(&lc,
file, offset, sizelimit,
LOOPDEV_FL_OFFSET | LOOPDEV_FL_SIZELIMIT);
if (res < 0) {
+ if (retries_left--)
+ goto retry;
loopcxt_deinit(&lc);
errx(EXIT_FAILURE, _("failed to inspect loop devices"));
}
@@ -698,6 +705,8 @@ int main(int argc, char **argv)
/* Once a loop is initialized RO, there is no
way to change its parameters. */
if (loopcxt_is_readonly(&lc) && !(lo_flags & LO_FLAGS_READ_ONLY)) {
+ if (retries_left--)
+ goto retry;
loopcxt_deinit(&lc);
errx(EXIT_FAILURE, _("%s: overlapping read-only loop device exists; use --force to ignore"),
loopcxt_get_device(&lc));
@@ -706,11 +715,15 @@ int main(int argc, char **argv)
/* This is no more supported, but check to be
* safe. */
if (loopcxt_get_encrypt_type(&lc, &lc_encrypt_type)) {
+ if (retries_left--)
+ goto retry;
loopcxt_deinit(&lc);
errx(EXIT_FAILURE, _("%s: encryption check failed"),
loopcxt_get_device(&lc));
}
if (lc_encrypt_type != LO_CRYPT_NONE) {
+ if (retries_left--)
+ goto retry;
loopcxt_deinit(&lc);
errx(EXIT_FAILURE, _("%s: encryption check failed"),
loopcxt_get_device(&lc));
@@ -722,6 +735,8 @@ int main(int argc, char **argv)
* user was already warned in past. */
lc.info.lo_flags &= !LO_FLAGS_AUTOCLEAR;
if (loopcxt_set_status(&lc)) {
+ if (retries_left--)
+ goto retry;
loopcxt_deinit(&lc);
errx(EXIT_FAILURE, _("%s: failed to re-use loop device"),
loopcxt_get_device(&lc));
--
2.9.2
--
Best Regards / S pozdravem,
Stanislav Brabec
software developer
---------------------------------------------------------------------
SUSE LINUX, s. r. o. e-mail: sbrabec@xxxxxxxx
Křižíkova 148/34 (Corso IIa) tel: +49 911 7405384547
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