[dm-devel] [PATCH v2 08/14] libmultipath: sysfs_attr_set_value(): don't return 0 on partial write
mwilck at suse.com
mwilck at suse.com
Wed Jul 13 08:20:43 UTC 2022
From: Martin Wilck <mwilck at suse.com>
sysfs_attr_set_value() returned 0 if not all requested bytes were written.
Change this to return the number of bytes written. Error checking is now
somewhat more involved; provide a helper macro for it.
Signed-off-by: Martin Wilck <mwilck at suse.com>
---
libmultipath/configure.c | 10 ++++--
libmultipath/discovery.c | 74 +++++++++++++++++++++++++---------------
libmultipath/sysfs.c | 6 ++--
libmultipath/sysfs.h | 10 ++++++
4 files changed, 66 insertions(+), 34 deletions(-)
diff --git a/libmultipath/configure.c b/libmultipath/configure.c
index 467bbaa..0607dba 100644
--- a/libmultipath/configure.c
+++ b/libmultipath/configure.c
@@ -568,6 +568,7 @@ sysfs_set_max_sectors_kb(struct multipath *mpp, int is_reload)
struct pathgroup * pgp;
struct path *pp;
char buff[11];
+ ssize_t len;
int i, j, ret, err = 0;
struct udev_device *udd;
int max_sectors_kb;
@@ -600,14 +601,17 @@ sysfs_set_max_sectors_kb(struct multipath *mpp, int is_reload)
}
}
snprintf(buff, 11, "%d", max_sectors_kb);
+ len = strlen(buff);
vector_foreach_slot (mpp->pg, pgp, i) {
vector_foreach_slot(pgp->paths, pp, j) {
ret = sysfs_attr_set_value(pp->udev,
"queue/max_sectors_kb",
- buff, strlen(buff));
- if (ret < 0) {
- condlog(1, "failed setting max_sectors_kb on %s : %s", pp->dev, strerror(-ret));
+ buff, len);
+ if (ret != len) {
+ log_sysfs_attr_set_value(1, ret,
+ "failed setting max_sectors_kb on %s",
+ pp->dev);
err = 1;
}
}
diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index 54b1caf..ee29009 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -598,13 +598,15 @@ sysfs_set_eh_deadline(struct path *pp)
len = sprintf(value, "%d", pp->eh_deadline);
ret = sysfs_attr_set_value(hostdev, "eh_deadline",
- value, len + 1);
+ value, len);
/*
* not all scsi drivers support setting eh_deadline, so failing
* is totally reasonable
*/
- if (ret <= 0)
- condlog(3, "%s: failed to set eh_deadline to %s, error %d", udev_device_get_sysname(hostdev), value, -ret);
+ if (ret != len)
+ log_sysfs_attr_set_value(3, ret,
+ "%s: failed to set eh_deadline to %s",
+ udev_device_get_sysname(hostdev), value);
udev_device_unref(hostdev);
return (ret <= 0);
@@ -667,19 +669,22 @@ sysfs_set_rport_tmo(struct multipath *mpp, struct path *pp)
pp->fast_io_fail != MP_FAST_IO_FAIL_OFF) {
/* Check if we need to temporarily increase dev_loss_tmo */
if ((unsigned int)pp->fast_io_fail >= tmo) {
+ ssize_t len;
+
/* Increase dev_loss_tmo temporarily */
snprintf(value, sizeof(value), "%u",
(unsigned int)pp->fast_io_fail + 1);
+ len = strlen(value);
ret = sysfs_attr_set_value(rport_dev, "dev_loss_tmo",
- value, strlen(value));
- if (ret <= 0) {
+ value, len);
+ if (ret != len) {
if (ret == -EBUSY)
condlog(3, "%s: rport blocked",
rport_id);
else
- condlog(0, "%s: failed to set "
- "dev_loss_tmo to %s, error %d",
- rport_id, value, -ret);
+ log_sysfs_attr_set_value(0, ret,
+ "%s: failed to set dev_loss_tmo to %s",
+ rport_id, value);
goto out;
}
}
@@ -691,32 +696,39 @@ sysfs_set_rport_tmo(struct multipath *mpp, struct path *pp)
pp->dev_loss = DEFAULT_DEV_LOSS_TMO;
}
if (pp->fast_io_fail != MP_FAST_IO_FAIL_UNSET) {
+ ssize_t len;
+
if (pp->fast_io_fail == MP_FAST_IO_FAIL_OFF)
sprintf(value, "off");
else if (pp->fast_io_fail == MP_FAST_IO_FAIL_ZERO)
sprintf(value, "0");
else
snprintf(value, 16, "%u", pp->fast_io_fail);
+ len = strlen(value);
ret = sysfs_attr_set_value(rport_dev, "fast_io_fail_tmo",
- value, strlen(value));
- if (ret <= 0) {
+ value, len);
+ if (ret != len) {
if (ret == -EBUSY)
condlog(3, "%s: rport blocked", rport_id);
else
- condlog(0, "%s: failed to set fast_io_fail_tmo to %s, error %d",
- rport_id, value, -ret);
+ log_sysfs_attr_set_value(0, ret,
+ "%s: failed to set fast_io_fail_tmo to %s",
+ rport_id, value);
}
}
if (pp->dev_loss != DEV_LOSS_TMO_UNSET) {
+ ssize_t len;
+
snprintf(value, 16, "%u", pp->dev_loss);
- ret = sysfs_attr_set_value(rport_dev, "dev_loss_tmo",
- value, strlen(value));
- if (ret <= 0) {
+ len = strlen(value);
+ ret = sysfs_attr_set_value(rport_dev, "dev_loss_tmo", value, len);
+ if (ret != len) {
if (ret == -EBUSY)
condlog(3, "%s: rport blocked", rport_id);
else
- condlog(0, "%s: failed to set dev_loss_tmo to %s, error %d",
- rport_id, value, -ret);
+ log_sysfs_attr_set_value(0, ret,
+ "%s: failed to set dev_loss_tmo to %s",
+ rport_id, value);
}
}
out:
@@ -754,12 +766,16 @@ sysfs_set_session_tmo(struct path *pp)
condlog(3, "%s: can't set fast_io_fail_tmo to '0'"
"on iSCSI", pp->dev);
} else {
+ ssize_t len, ret;
+
snprintf(value, 11, "%u", pp->fast_io_fail);
- if (sysfs_attr_set_value(session_dev, "recovery_tmo",
- value, strlen(value)) <= 0) {
- condlog(3, "%s: Failed to set recovery_tmo, "
- " error %d", pp->dev, errno);
- }
+ len = strlen(value);
+ ret = sysfs_attr_set_value(session_dev, "recovery_tmo",
+ value, len);
+ if (ret != len)
+ log_sysfs_attr_set_value(3, ret,
+ "%s: Failed to set recovery_tmo to %s",
+ pp->dev, value);
}
}
udev_device_unref(session_dev);
@@ -802,12 +818,16 @@ sysfs_set_nexus_loss_tmo(struct path *pp)
pp->sg_id.channel, pp->sg_id.scsi_id, end_dev_id);
if (pp->dev_loss != DEV_LOSS_TMO_UNSET) {
+ ssize_t len, ret;
+
snprintf(value, 11, "%u", pp->dev_loss);
- if (sysfs_attr_set_value(sas_dev, "I_T_nexus_loss_timeout",
- value, strlen(value)) <= 0)
- condlog(3, "%s: failed to update "
- "I_T Nexus loss timeout, error %d",
- pp->dev, errno);
+ len = strlen(value);
+ ret = sysfs_attr_set_value(sas_dev, "I_T_nexus_loss_timeout",
+ value, len);
+ if (ret != len)
+ log_sysfs_attr_set_value(3, ret,
+ "%s: failed to update I_T Nexus loss timeout",
+ pp->dev);
}
udev_device_unref(sas_dev);
return;
diff --git a/libmultipath/sysfs.c b/libmultipath/sysfs.c
index 125f1c2..9c84af7 100644
--- a/libmultipath/sysfs.c
+++ b/libmultipath/sysfs.c
@@ -134,7 +134,7 @@ ssize_t sysfs_attr_set_value(struct udev_device *dev, const char *attr_name,
/* write attribute value */
fd = open(devpath, O_WRONLY);
if (fd < 0) {
- condlog(2, "%s: attribute '%s' can not be opened: %s",
+ condlog(3, "%s: attribute '%s' can not be opened: %s",
__func__, devpath, strerror(errno));
return -errno;
}
@@ -144,11 +144,9 @@ ssize_t sysfs_attr_set_value(struct udev_device *dev, const char *attr_name,
size = -errno;
condlog(3, "%s: write to %s failed: %s", __func__,
devpath, strerror(errno));
- } else if (size < (ssize_t)value_len) {
+ } else if (size < (ssize_t)value_len)
condlog(3, "%s: underflow writing %zu bytes to %s. Wrote %zd bytes",
__func__, value_len, devpath, size);
- size = 0;
- }
close(fd);
return size;
diff --git a/libmultipath/sysfs.h b/libmultipath/sysfs.h
index cdc84e4..799f68e 100644
--- a/libmultipath/sysfs.h
+++ b/libmultipath/sysfs.h
@@ -5,6 +5,7 @@
#ifndef _LIBMULTIPATH_SYSFS_H
#define _LIBMULTIPATH_SYSFS_H
#include <stdbool.h>
+#include "strbuf.h"
ssize_t sysfs_attr_set_value(struct udev_device *dev, const char *attr_name,
const char * value, size_t value_len);
@@ -25,6 +26,15 @@ ssize_t sysfs_bin_attr_get_value(struct udev_device *dev, const char *attr_name,
sysfs_attr_value_ok(__rc, __l); \
})
+#define log_sysfs_attr_set_value(prio, rc, fmt, __args...) \
+do { \
+ STRBUF_ON_STACK(__buf); \
+ if (print_strbuf(&__buf, fmt, ##__args) >= 0 && \
+ print_strbuf(&__buf, ": %s", rc < 0 ? strerror(-rc) : \
+ "write underflow") >= 0) \
+ condlog(prio, "%s", get_strbuf_str(&__buf)); \
+} while(0)
+
int sysfs_get_size (struct path *pp, unsigned long long * size);
int sysfs_check_holders(char * check_devt, char * new_devt);
bool sysfs_is_multipathed(struct path *pp, bool set_wwid);
--
2.36.1
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