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Mtab check optional

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There are situations when /etc/mtab is not present in the
system (e.g. in certain container images). This blocks
stop/remove operations. With making this check optional
the duty of checking mounts falls to kernel.
Test modified to check operations with and without mtab.

Signed-off-by: Daniel Madej <daniel.madej@huawei.com>
This commit is contained in:
Daniel Madej
2024-09-10 10:39:39 +02:00
parent 7a3b0672f2
commit a2f3cc1f4a
3 changed files with 113 additions and 42 deletions
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71
casadm/cas_lib.c
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@@ -45,8 +45,8 @@
#define CORE_ADD_MAX_TIMEOUT 30
int is_cache_mounted(int cache_id);
int is_core_mounted(int cache_id, int core_id);
bool cache_mounts_detected(int cache_id);
bool core_mounts_detected(int cache_id, int core_id);
/* KCAS_IOCTL_CACHE_CHECK_DEVICE wrapper */
int _check_cache_device(const char *device_path,
@@ -1119,7 +1119,7 @@ int stop_cache(uint16_t cache_id, int flush)
int status;
/* Don't stop instance with mounted filesystem */
if (is_cache_mounted(cache_id) == FAILURE)
if (cache_mounts_detected(cache_id))
return FAILURE;
fd = open_ctrl_device();
@@ -1803,58 +1803,60 @@ int add_core(unsigned int cache_id, unsigned int core_id, const char *core_devic
return SUCCESS;
}
int _check_if_mounted(int cache_id, int core_id)
bool _device_mounts_detected(int cache_id, int core_id)
{
FILE *mtab;
struct mntent *mstruct;
char dev_buf[80];
int difference = 0, error = 0;
int no_match = 0, error = 0, cmplen = 0;
if (core_id >= 0) {
/* verify if specific core is mounted */
snprintf(dev_buf, sizeof(dev_buf), "/dev/cas%d-%d", cache_id, core_id);
cmplen = snprintf(dev_buf, sizeof(dev_buf), "/dev/cas%d-%d", cache_id, core_id);
} else {
/* verify if any core from given cache is mounted */
snprintf(dev_buf, sizeof(dev_buf), "/dev/cas%d-", cache_id);
/* verify if any core from given cache is mounted
do not compare terminating NULL for cache */
cmplen = snprintf(dev_buf, sizeof(dev_buf), "/dev/cas%d-", cache_id) - 1;
}
mtab = setmntent("/etc/mtab", "r");
if (!mtab)
{
cas_printf(LOG_ERR, "Error while accessing /etc/mtab\n");
return FAILURE;
if (!mtab) {
/* if /etc/mtab not found then the kernel will check for mounts */
return false;
}
while ((mstruct = getmntent(mtab)) != NULL) {
error = strcmp_s(mstruct->mnt_fsname, PATH_MAX, dev_buf, &difference);
error = strcmp_s(mstruct->mnt_fsname, cmplen, dev_buf, &no_match);
/* mstruct->mnt_fsname is /dev/... block device path, not a mountpoint */
if (error != EOK)
return FAILURE;
if (!difference) {
if (core_id<0) {
cas_printf(LOG_ERR,
"Can't stop cache instance %d. Device %s is mounted!\n",
cache_id, mstruct->mnt_fsname);
} else {
cas_printf(LOG_ERR,
"Can't remove core %d from cache %d."
" Device %s is mounted!\n",
core_id, cache_id, mstruct->mnt_fsname);
}
return FAILURE;
return false;
if (no_match)
continue;
if (core_id < 0) {
cas_printf(LOG_ERR,
"Can't stop cache instance %d. Device %s is mounted!\n",
cache_id, mstruct->mnt_fsname);
} else {
cas_printf(LOG_ERR,
"Can't remove core %d from cache %d."
" Device %s is mounted!\n",
core_id, cache_id, mstruct->mnt_fsname);
}
return true;
}
return SUCCESS;
return false;
}
int is_cache_mounted(int cache_id)
bool cache_mounts_detected(int cache_id)
{
return _check_if_mounted(cache_id, -1);
return _device_mounts_detected(cache_id, -1);
}
int is_core_mounted(int cache_id, int core_id)
bool core_mounts_detected(int cache_id, int core_id)
{
return _check_if_mounted(cache_id, core_id);
return _device_mounts_detected(cache_id, core_id);
}
int remove_core(unsigned int cache_id, unsigned int core_id,
@@ -1864,7 +1866,7 @@ int remove_core(unsigned int cache_id, unsigned int core_id,
struct kcas_remove_core cmd;
/* don't even attempt ioctl if filesystem is mounted */
if (SUCCESS != is_core_mounted(cache_id, core_id)) {
if (core_mounts_detected(cache_id, core_id)) {
return FAILURE;
}
@@ -1929,11 +1931,6 @@ int remove_inactive_core(unsigned int cache_id, unsigned int core_id,
int fd = 0;
struct kcas_remove_inactive cmd;
/* don't even attempt ioctl if filesystem is mounted */
if (SUCCESS != is_core_mounted(cache_id, core_id)) {
return FAILURE;
}
fd = open_ctrl_device();
if (fd == -1)
return FAILURE;