On Mon, May 23, 2016 at 12:20:28PM +0200, Hannes Reinecke wrote: > Recent kernels have an 'access_state' attribute which allows > us to read the asymmetric access state directly from sysfs.
Neat. Just some thoughts. I'm not sure if you want to add a prioritizer option to be able to change what the pref bit does (perhaps "no_exclusive_pref_bit"). Also, we should probably make the alua prioritizer default to the same pref bit behavior as the sysfs prioritizer. ACK -Ben > > Signed-off-by: Hannes Reinecke <[email protected]> > --- > libmultipath/discovery.c | 33 +++++++++++++++++++++++++++++ > libmultipath/discovery.h | 2 ++ > libmultipath/prio.h | 1 + > libmultipath/prioritizers/Makefile | 3 ++- > libmultipath/prioritizers/sysfs.c | 43 > ++++++++++++++++++++++++++++++++++++++ > libmultipath/propsel.c | 6 +++++- > multipath/multipath.conf.5 | 14 ++++++++++++- > 7 files changed, 99 insertions(+), 3 deletions(-) > create mode 100644 libmultipath/prioritizers/sysfs.c > > diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c > index a364056..4a4b828 100644 > --- a/libmultipath/discovery.c > +++ b/libmultipath/discovery.c > @@ -208,6 +208,8 @@ declare_sysfs_get_str(devtype); > declare_sysfs_get_str(vendor); > declare_sysfs_get_str(model); > declare_sysfs_get_str(rev); > +declare_sysfs_get_str(access_state); > +declare_sysfs_get_str(preferred_path); > > ssize_t > sysfs_get_vpd (struct udev_device * udev, int pg, > @@ -483,6 +485,37 @@ int sysfs_get_iscsi_ip_address(struct path *pp, char > *ip_address) > return 1; > } > > +int > +sysfs_get_asymmetric_access_state(struct path *pp, char *buff, int buflen) > +{ > + struct udev_device *parent = pp->udev; > + char value[16], *eptr; > + unsigned int preferred; > + > + while (parent) { > + const char *subsys = udev_device_get_subsystem(parent); > + if (subsys && !strncmp(subsys, "scsi", 4)) > + break; > + parent = udev_device_get_parent(parent); > + } > + > + if (!parent) > + return -1; > + > + if (sysfs_get_access_state(parent, buff, buflen) <= 0) > + return -1; > + > + if (sysfs_get_preferred_path(parent, value, 16) <= 0) > + return 0; > + > + preferred = strtoul(value, &eptr, 0); > + if (value == eptr || preferred == ULONG_MAX) { > + /* Parse error, ignore */ > + return 0; > + } > + return preferred; > +} > + > static void > sysfs_set_rport_tmo(struct multipath *mpp, struct path *pp) > { > diff --git a/libmultipath/discovery.h b/libmultipath/discovery.h > index 5931bc6..b45c802 100644 > --- a/libmultipath/discovery.h > +++ b/libmultipath/discovery.h > @@ -47,6 +47,8 @@ int sysfs_get_host_pci_name(struct path *pp, char > *pci_name); > int sysfs_get_iscsi_ip_address(struct path *pp, char *ip_address); > ssize_t sysfs_get_vpd (struct udev_device * udev, int pg, unsigned char * > buff, > size_t len); > +int sysfs_get_asymmetric_access_state(struct path *pp, > + char *buff, int buflen); > > /* > * discovery bitmask > diff --git a/libmultipath/prio.h b/libmultipath/prio.h > index 495688f..65abf54 100644 > --- a/libmultipath/prio.h > +++ b/libmultipath/prio.h > @@ -29,6 +29,7 @@ struct path; > #define PRIO_RDAC "rdac" > #define PRIO_DATACORE "datacore" > #define PRIO_WEIGHTED_PATH "weightedpath" > +#define PRIO_SYSFS "sysfs" > > /* > * Value used to mark the fact prio was not defined > diff --git a/libmultipath/prioritizers/Makefile > b/libmultipath/prioritizers/Makefile > index 6cfac88..0d1857f 100644 > --- a/libmultipath/prioritizers/Makefile > +++ b/libmultipath/prioritizers/Makefile > @@ -15,7 +15,8 @@ LIBS = \ > libpriodatacore.so \ > libpriohds.so \ > libprioweightedpath.so \ > - libprioiet.so > + libprioiet.so \ > + libpriosysfs.so > > CFLAGS += -I.. > > diff --git a/libmultipath/prioritizers/sysfs.c > b/libmultipath/prioritizers/sysfs.c > new file mode 100644 > index 0000000..35a5c83 > --- /dev/null > +++ b/libmultipath/prioritizers/sysfs.c > @@ -0,0 +1,43 @@ > +/* > + * sysfs.c > + * > + * Copyright(c) 2016 Hannes Reinecke, SUSE Linux GmbH > + */ > + > +#include <stdio.h> > + > +#include "structs.h" > +#include "discovery.h" > +#include "prio.h" > + > +static const struct { > + unsigned char value; > + char *name; > +} sysfs_access_state_map[] = { > + { 50, "active/optimized" }, > + { 10, "active/non-optimized" }, > + { 5, "lba-dependent" }, > + { 1, "standby" }, > +}; > + > +int getprio (struct path * pp, char * args) > +{ > + int prio = 0, rc, i; > + char buff[512]; > + > + rc = sysfs_get_asymmetric_access_state(pp, buff, 512); > + if (rc < 0) > + return PRIO_UNDEF; > + prio = 0; > + for (i = 0; i < 4; i++) { > + if (!strncmp(buff, sysfs_access_state_map[i].name, > + strlen(sysfs_access_state_map[i].name))) { > + prio = sysfs_access_state_map[i].value; > + break; > + } > + } > + if (rc > 0) > + prio += 80; > + > + return prio; > +} > diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c > index 8abe360..b0182de 100644 > --- a/libmultipath/propsel.c > +++ b/libmultipath/propsel.c > @@ -374,6 +374,7 @@ detect_prio(struct path * pp) > int ret; > struct prio *p = &pp->prio; > int tpgs = 0; > + char buff[512]; > > if ((tpgs = get_target_port_group_support(pp->fd)) <= 0) > return; > @@ -383,7 +384,10 @@ detect_prio(struct path * pp) > return; > if (get_asymmetric_access_state(pp->fd, ret) < 0) > return; > - prio_get(p, PRIO_ALUA, DEFAULT_PRIO_ARGS); > + if (sysfs_get_asymmetric_access_state(pp, buff, 512) < 0) > + prio_get(p, PRIO_ALUA, DEFAULT_PRIO_ARGS); > + else > + prio_get(p, PRIO_SYSFS, DEFAULT_PRIO_ARGS); > } > > #define set_prio(src, msg) \ > diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5 > index 2ff88c4..aaaa01b 100644 > --- a/multipath/multipath.conf.5 > +++ b/multipath/multipath.conf.5 > @@ -203,6 +203,10 @@ Generate the path priority for NetApp arrays. > .B rdac > Generate the path priority for LSI/Engenio/NetApp E-Series RDAC controller. > .TP > +.B sysfs > +Use the sysfs attributes access_state and preferred_path to generate the > +path priority. > +.TP > .B hp_sw > Generate the path priority for Compaq/HP controller in > active/standby mode. > @@ -449,8 +453,16 @@ If set to > .I yes > , multipath will try to detect if the device supports ALUA. If so, the device > will automatically use the > +.I sysfs > +prioritizer if the required sysfs attributes > +.I access_state > +and > +.I preferred_path > +are supported, or the > .I alua > -prioritizer. If not, the prioritizer will be selected as usual. Default is > +prioritizer if not. If set to > +.I no > +, the prioritizer will be selected as usual. Default is > .I no > .TP > .B force_sync > -- > 2.6.6 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
