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zpool: Add slot power control, print power status
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Add `zpool` flags to control the slot power to drives.  This assumes
your SAS or NVMe enclosure supports slot power control via sysfs.

The new `--power` flag is added to `zpool offline|online|clear`:

    zpool offline --power <pool> <device>    Turn off device slot power
    zpool online --power <pool> <device>     Turn on device slot power
    zpool clear --power <pool> [device]      Turn on device slot power

If the ZPOOL_AUTO_POWER_ON_SLOT env var is set, then the '--power'
option is automatically implied for `zpool online` and `zpool clear`
and does not need to be passed.

zpool status also gets a --power option to print the slot power status.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mart Frauenlob <AllKind@fastest.cc>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #15662
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tonyhutter authored Dec 21, 2023
1 parent 6930ecb commit a9520e6
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Showing 16 changed files with 875 additions and 65 deletions.
14 changes: 14 additions & 0 deletions cmd/zpool/os/freebsd/zpool_vdev_os.c
Original file line number Diff line number Diff line change
Expand Up @@ -124,3 +124,17 @@ check_file(const char *file, boolean_t force, boolean_t isspare)
{
return (check_file_generic(file, force, isspare));
}

int
zpool_power_current_state(zpool_handle_t *zhp, char *vdev)
{
/* Enclosure slot power not supported on FreeBSD yet */
return (-1);
}

int
zpool_power(zpool_handle_t *zhp, char *vdev, boolean_t turn_on)
{
/* Enclosure slot power not supported on FreeBSD yet */
return (ENOTSUP);
}
255 changes: 255 additions & 0 deletions cmd/zpool/os/linux/zpool_vdev_os.c
Original file line number Diff line number Diff line change
Expand Up @@ -416,3 +416,258 @@ check_file(const char *file, boolean_t force, boolean_t isspare)
{
return (check_file_generic(file, force, isspare));
}

/*
* Read from a sysfs file and return an allocated string. Removes
* the newline from the end of the string if there is one.
*
* Returns a string on success (which must be freed), or NULL on error.
*/
static char *zpool_sysfs_gets(char *path)
{
int fd;
struct stat statbuf;
char *buf = NULL;
ssize_t count = 0;
fd = open(path, O_RDONLY);
if (fd < 0)
return (NULL);

if (fstat(fd, &statbuf) != 0) {
close(fd);
return (NULL);
}

buf = calloc(sizeof (*buf), statbuf.st_size + 1);
if (buf == NULL) {
close(fd);
return (NULL);
}

/*
* Note, we can read less bytes than st_size, and that's ok. Sysfs
* files will report their size is 4k even if they only return a small
* string.
*/
count = read(fd, buf, statbuf.st_size);
if (count < 0) {
/* Error doing read() or we overran the buffer */
close(fd);
free(buf);
return (NULL);
}

/* Remove trailing newline */
if (buf[count - 1] == '\n')
buf[count - 1] = 0;

close(fd);

return (buf);
}

/*
* Write a string to a sysfs file.
*
* Returns 0 on success, non-zero otherwise.
*/
static int zpool_sysfs_puts(char *path, char *str)
{
FILE *file;

file = fopen(path, "w");
if (!file) {
return (-1);
}

if (fputs(str, file) < 0) {
fclose(file);
return (-2);
}
fclose(file);
return (0);
}

/* Given a vdev nvlist_t, rescan its enclosure sysfs path */
static void
rescan_vdev_config_dev_sysfs_path(nvlist_t *vdev_nv)
{
update_vdev_config_dev_sysfs_path(vdev_nv,
fnvlist_lookup_string(vdev_nv, ZPOOL_CONFIG_PATH),
ZPOOL_CONFIG_VDEV_ENC_SYSFS_PATH);
}

/*
* Given a power string: "on", "off", "1", or "0", return 0 if it's an
* off value, 1 if it's an on value, and -1 if the value is unrecognized.
*/
static int zpool_power_parse_value(char *str)
{
if ((strcmp(str, "off") == 0) || (strcmp(str, "0") == 0))
return (0);

if ((strcmp(str, "on") == 0) || (strcmp(str, "1") == 0))
return (1);

return (-1);
}

/*
* Given a vdev string return an allocated string containing the sysfs path to
* its power control file. Also do a check if the power control file really
* exists and has correct permissions.
*
* Example returned strings:
*
* /sys/class/enclosure/0:0:122:0/10/power_status
* /sys/bus/pci/slots/10/power
*
* Returns allocated string on success (which must be freed), NULL on failure.
*/
static char *
zpool_power_sysfs_path(zpool_handle_t *zhp, char *vdev)
{
const char *enc_sysfs_dir = NULL;
char *path = NULL;
nvlist_t *vdev_nv = zpool_find_vdev(zhp, vdev, NULL, NULL, NULL);

if (vdev_nv == NULL) {
return (NULL);
}

/* Make sure we're getting the updated enclosure sysfs path */
rescan_vdev_config_dev_sysfs_path(vdev_nv);

if (nvlist_lookup_string(vdev_nv, ZPOOL_CONFIG_VDEV_ENC_SYSFS_PATH,
&enc_sysfs_dir) != 0) {
return (NULL);
}

if (asprintf(&path, "%s/power_status", enc_sysfs_dir) == -1)
return (NULL);

if (access(path, W_OK) != 0) {
free(path);
path = NULL;
/* No HDD 'power_control' file, maybe it's NVMe? */
if (asprintf(&path, "%s/power", enc_sysfs_dir) == -1) {
return (NULL);
}

if (access(path, R_OK | W_OK) != 0) {
/* Not NVMe either */
free(path);
return (NULL);
}
}

return (path);
}

/*
* Given a path to a sysfs power control file, return B_TRUE if you should use
* "on/off" words to control it, or B_FALSE otherwise ("0/1" to control).
*/
static boolean_t
zpool_power_use_word(char *sysfs_path)
{
if (strcmp(&sysfs_path[strlen(sysfs_path) - strlen("power_status")],
"power_status") == 0) {
return (B_TRUE);
}
return (B_FALSE);
}

/*
* Check the sysfs power control value for a vdev.
*
* Returns:
* 0 - Power is off
* 1 - Power is on
* -1 - Error or unsupported
*/
int
zpool_power_current_state(zpool_handle_t *zhp, char *vdev)
{
char *val;
int rc;

char *path = zpool_power_sysfs_path(zhp, vdev);
if (path == NULL)
return (-1);

val = zpool_sysfs_gets(path);
if (val == NULL) {
free(path);
return (-1);
}

rc = zpool_power_parse_value(val);
free(val);
free(path);
return (rc);
}

/*
* Turn on or off the slot to a device
*
* Device path is the full path to the device (like /dev/sda or /dev/sda1).
*
* Return code:
* 0: Success
* ENOTSUP: Power control not supported for OS
* EBADSLT: Couldn't read current power state
* ENOENT: No sysfs path to power control
* EIO: Couldn't write sysfs power value
* EBADE: Sysfs power value didn't change
*/
int
zpool_power(zpool_handle_t *zhp, char *vdev, boolean_t turn_on)
{
char *sysfs_path;
const char *val;
int rc;
int timeout_ms;

rc = zpool_power_current_state(zhp, vdev);
if (rc == -1) {
return (EBADSLT);
}

/* Already correct value? */
if (rc == (int)turn_on)
return (0);

sysfs_path = zpool_power_sysfs_path(zhp, vdev);
if (sysfs_path == NULL)
return (ENOENT);

if (zpool_power_use_word(sysfs_path)) {
val = turn_on ? "on" : "off";
} else {
val = turn_on ? "1" : "0";
}

rc = zpool_sysfs_puts(sysfs_path, (char *)val);

free(sysfs_path);
if (rc != 0) {
return (EIO);
}

/*
* Wait up to 30 seconds for sysfs power value to change after
* writing it.
*/
timeout_ms = zpool_getenv_int("ZPOOL_POWER_ON_SLOT_TIMEOUT_MS", 30000);
for (int i = 0; i < MAX(1, timeout_ms / 200); i++) {
rc = zpool_power_current_state(zhp, vdev);
if (rc == (int)turn_on)
return (0); /* success */

fsleep(0.200); /* 200ms */
}

/* sysfs value never changed */
return (EBADE);
}
4 changes: 4 additions & 0 deletions cmd/zpool/zpool_iter.c
Original file line number Diff line number Diff line change
Expand Up @@ -554,6 +554,10 @@ for_each_vdev_run_cb(void *zhp_data, nvlist_t *nv, void *cb_vcdl)
if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &path) != 0)
return (1);

/* Make sure we're getting the updated enclosure sysfs path */
update_vdev_config_dev_sysfs_path(nv, path,
ZPOOL_CONFIG_VDEV_ENC_SYSFS_PATH);

nvlist_lookup_string(nv, ZPOOL_CONFIG_VDEV_ENC_SYSFS_PATH,
&vdev_enc_sysfs_path);

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