On Fri, Sep 14, 2018 at 02:50:59PM +0200, Martin Wilck wrote: Reviewed-by: Benjamin Marzinski <[email protected]>
> The path detection logic of the NVMe code relies on the "slaves" > symlinks from NVMe subsys to controllers in sysfs, which have > been removed in the 4.16 kernel. > > With this patch, we use the symlinks on the NVMe subsys level > instead. > > Example: a multipathed NVMe subsystem with 2 controllers: > > /sys/devices/virtual/nvme-subsystem/nvme-subsys2/nvme2n1 > /sys/devices/virtual/nvme-fabrics/ctl/nvme2/nvme2c6n1 > /sys/devices/virtual/nvme-fabrics/ctl/nvme3/nvme2c8n1 > > The controllers are found from the subsystem like this: > > /sys/devices/virtual/nvme-subsystem/nvme-subsys2/nvme2 -> > ../../nvme-fabrics/ctl/nvme2 > /sys/devices/virtual/nvme-subsystem/nvme-subsys2/nvme3 -> > ../../nvme-fabrics/ctl/nvme3 > > Signed-off-by: Martin Wilck <[email protected]> > --- > libmultipath/foreign/nvme.c | 153 ++++++++++++++++++++++++++++++------ > 1 file changed, 127 insertions(+), 26 deletions(-) > > diff --git a/libmultipath/foreign/nvme.c b/libmultipath/foreign/nvme.c > index 280b6bd2..fca3235f 100644 > --- a/libmultipath/foreign/nvme.c > +++ b/libmultipath/foreign/nvme.c > @@ -26,6 +26,7 @@ > #include <limits.h> > #include <dirent.h> > #include <errno.h> > +#include <ctype.h> > #include "vector.h" > #include "generic.h" > #include "foreign.h" > @@ -442,17 +443,92 @@ _find_path_by_syspath(struct nvme_map *map, const char > *syspath) > return NULL; > } > > -static int no_dotfiles(const struct dirent *di) > +static void _udev_device_unref(void *p) > { > - return di->d_name[0] != '.'; > + udev_device_unref(p); > } > > -static void _find_slaves(struct context *ctx, struct nvme_map *map) > +static void _udev_enumerate_unref(void *p) > { > - char pathbuf[PATH_MAX]; > + udev_enumerate_unref(p); > +} > + > +static int _dirent_controller(const struct dirent *di) > +{ > + static const char nvme_prefix[] = "nvme"; > + const char *p; > + > +#ifdef _DIRENT_HAVE_D_TYPE > + if (di->d_type != DT_LNK) > + return 0; > +#endif > + if (strncmp(di->d_name, nvme_prefix, sizeof(nvme_prefix) - 1)) > + return 0; > + p = di->d_name + sizeof(nvme_prefix) - 1; > + if (*p == '\0' || !isdigit(*p)) > + return 0; > + for (++p; *p != '\0'; ++p) > + if (!isdigit(*p)) > + return 0; > + return 1; > +} > + > +/* Find the block device for a given nvme controller */ > +struct udev_device *get_ctrl_blkdev(const struct context *ctx, > + struct udev_device *ctrl) > +{ > + struct udev_list_entry *item; > + struct udev_device *blkdev = NULL; > + struct udev_enumerate *enm = udev_enumerate_new(ctx->udev); > + > + if (enm == NULL) > + return NULL; > + > + pthread_cleanup_push(_udev_enumerate_unref, enm); > + if (udev_enumerate_add_match_parent(enm, ctrl) < 0) > + goto out; > + if (udev_enumerate_add_match_subsystem(enm, "block")) > + goto out; > + > + if (udev_enumerate_scan_devices(enm) < 0) { > + condlog(1, "%s: %s: error enumerating devices", __func__, THIS); > + goto out; > + } > + > + for (item = udev_enumerate_get_list_entry(enm); > + item != NULL; > + item = udev_list_entry_get_next(item)) { > + struct udev_device *tmp; > + > + tmp = udev_device_new_from_syspath(ctx->udev, > + udev_list_entry_get_name(item)); > + if (tmp == NULL) > + continue; > + if (!strcmp(udev_device_get_devtype(tmp), "disk")) { > + blkdev = tmp; > + break; > + } else > + udev_device_unref(tmp); > + } > + > + if (blkdev == NULL) > + condlog(1, "%s: %s: failed to get blockdev for %s", > + __func__, THIS, udev_device_get_sysname(ctrl)); > + else > + condlog(5, "%s: %s: got %s", __func__, THIS, > + udev_device_get_sysname(blkdev)); > +out: > + pthread_cleanup_pop(1); > + return blkdev; > +} > + > +static void _find_controllers(struct context *ctx, struct nvme_map *map) > +{ > + char pathbuf[PATH_MAX], realbuf[PATH_MAX]; > struct dirent **di = NULL; > + struct udev_device *subsys; > struct nvme_path *path; > - int r, i; > + int r, i, n; > > if (map == NULL || map->udev == NULL) > return; > @@ -460,33 +536,65 @@ static void _find_slaves(struct context *ctx, struct > nvme_map *map) > vector_foreach_slot(map->pathvec, path, i) > path->seen = false; > > - snprintf(pathbuf, sizeof(pathbuf), > - "%s/slaves", > - udev_device_get_syspath(map->udev)); > + subsys = udev_device_get_parent_with_subsystem_devtype(map->udev, > + "nvme-subsystem", > + NULL); > + if (subsys == NULL) { > + condlog(1, "%s: %s: BUG: no NVME subsys for %s", __func__, THIS, > + udev_device_get_sysname(map->udev)); > + return; > + } > > - r = scandir(pathbuf, &di, no_dotfiles, alphasort); > + n = snprintf(pathbuf, sizeof(pathbuf), "%s", > + udev_device_get_syspath(subsys)); > + r = scandir(pathbuf, &di, _dirent_controller, alphasort); > > if (r == 0) { > - condlog(3, "%s: %s: no paths for %s", __func__, THIS, > + condlog(3, "%s: %s: no controllers for %s", __func__, THIS, > udev_device_get_sysname(map->udev)); > return; > } else if (r < 0) { > - condlog(1, "%s: %s: error %d scanning paths of %s", __func__, > - THIS, errno, udev_device_get_sysname(map->udev)); > + condlog(1, "%s: %s: error %d scanning controllers of %s", > + __func__, THIS, errno, > + udev_device_get_sysname(map->udev)); > return; > } > > pthread_cleanup_push(free, di); > for (i = 0; i < r; i++) { > char *fn = di[i]->d_name; > - struct udev_device *udev; > + struct udev_device *ctrl, *udev; > + > + if (snprintf(pathbuf + n, sizeof(pathbuf) - n, "/%s", fn) > + >= sizeof(pathbuf) - n) > + continue; > + if (realpath(pathbuf, realbuf) == NULL) { > + condlog(3, "%s: %s: realpath: %s", __func__, THIS, > + strerror(errno)); > + continue; > + } > + condlog(4, "%s: %s: found %s", __func__, THIS, realbuf); > > - if (snprintf(pathbuf, sizeof(pathbuf), "%s/slaves/%s", > - udev_device_get_syspath(map->udev), fn) > - >= sizeof(pathbuf)) > + ctrl = udev_device_new_from_syspath(ctx->udev, realbuf); > + if (ctrl == NULL) { > + condlog(1, "%s: %s: failed to get udev device for %s", > + __func__, THIS, realbuf); > + continue; > + } > + > + pthread_cleanup_push(_udev_device_unref, ctrl); > + udev = get_ctrl_blkdev(ctx, ctrl); > + /* > + * We give up the reference to the nvme device here and get > + * it back from the child below. > + * This way we don't need to worry about unreffing it. > + */ > + pthread_cleanup_pop(1); > + > + if (udev == NULL) > continue; > > - path = _find_path_by_syspath(map, pathbuf); > + path = _find_path_by_syspath(map, > udev_device_get_syspath(udev)); > if (path != NULL) { > path->seen = true; > condlog(4, "%s: %s already known", > @@ -494,13 +602,6 @@ static void _find_slaves(struct context *ctx, struct > nvme_map *map) > continue; > } > > - udev = udev_device_new_from_syspath(ctx->udev, pathbuf); > - if (udev == NULL) { > - condlog(1, "%s: %s: failed to get udev device for %s", > - __func__, THIS, fn); > - continue; > - } > - > path = calloc(1, sizeof(*path)); > if (path == NULL) > continue; > @@ -591,7 +692,7 @@ static int _add_map(struct context *ctx, struct > udev_device *ud, > return FOREIGN_ERR; > } > vector_set_slot(ctx->mpvec, map); > - _find_slaves(ctx, map); > + _find_controllers(ctx, map); > > return FOREIGN_CLAIMED; > } > @@ -688,7 +789,7 @@ void _check(struct context *ctx) > vector_foreach_slot(ctx->mpvec, gm, i) { > struct nvme_map *map = gen_mp_to_nvme(gm); > > - _find_slaves(ctx, map); > + _find_controllers(ctx, map); > } > } > > -- > 2.18.0 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
