| Message ID | 20180807222656.14346-2-keith.busch@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] Create Intel pmem shutdown latch rule | expand |
On Tue, 2018-08-07 at 16:26 -0600, Keith Busch wrote: > A user space rule saves the unsafe shutdown count to a fixed location > for Intel dimms so that non-root users can read it. If the smart command > submission fails, this patch uses that saved value in a newly added > ndctl_cmd "handle_error" callback. If the cached value is available, > the error handler will override the command status to success, and set > the valid flags for the shutdown count. > > Signed-off-by: Keith Busch <keith.busch@intel.com> > --- > ndctl/lib/intel.c | 34 +++++++++++++++++++++++++++++++++- > ndctl/lib/libndctl.c | 2 ++ > ndctl/lib/private.h | 1 + > 3 files changed, 36 insertions(+), 1 deletion(-) Looks good to me! > > diff --git a/ndctl/lib/intel.c b/ndctl/lib/intel.c > index 0abea1e..83f8203 100644 > --- a/ndctl/lib/intel.c > +++ b/ndctl/lib/intel.c > @@ -56,6 +56,38 @@ static struct ndctl_cmd *alloc_intel_cmd(struct ndctl_dimm *dimm, > return cmd; > } > > +/* > + * If provided, read the cached shutdown count in case the user does not have > + * access rights to run the smart command, and pretend the command was > + * successful with only the shutdown_count valid. > + */ > +static int intel_smart_handle_error(struct ndctl_cmd *cmd) > +{ > + struct ndctl_dimm *dimm = cmd->dimm; > + char *path = NULL, shutdown_count[16] = {}; > + int fd, rc = cmd->status; > + > + if (asprintf(&path, DEF_TMPFS_DIR "/%s/usc", > + ndctl_dimm_get_unique_id(dimm)) < 0) > + return rc; > + > + fd = open(path, O_RDONLY); > + if (fd < 0) > + goto free_path; > + > + if (read(fd, shutdown_count, sizeof(shutdown_count)) < 0) > + goto close; > + > + cmd->intel->smart.flags = ND_INTEL_SMART_SHUTDOWN_COUNT_VALID; > + cmd->intel->smart.shutdown_count = strtoull(shutdown_count, NULL, 0); > + rc = cmd->status = 0; > + close: > + close (fd); > + free_path: > + free(path); > + return rc; > +} > + > static struct ndctl_cmd *intel_dimm_cmd_new_smart(struct ndctl_dimm *dimm) > { > struct ndctl_cmd *cmd; > @@ -67,7 +99,7 @@ static struct ndctl_cmd *intel_dimm_cmd_new_smart(struct ndctl_dimm *dimm) > if (!cmd) > return NULL; > cmd->firmware_status = &cmd->intel->smart.status; > - > + cmd->handle_error = intel_smart_handle_error; > return cmd; > } > > diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c > index 47e005e..d94321e 100644 > --- a/ndctl/lib/libndctl.c > +++ b/ndctl/lib/libndctl.c > @@ -2651,6 +2651,8 @@ NDCTL_EXPORT int ndctl_cmd_submit(struct ndctl_cmd *cmd) > close(fd); > out: > cmd->status = rc; > + if (rc && cmd->handle_error) > + rc = cmd->handle_error(cmd); > return rc; > } > > diff --git a/ndctl/lib/private.h b/ndctl/lib/private.h > index a94f894..5812c85 100644 > --- a/ndctl/lib/private.h > +++ b/ndctl/lib/private.h > @@ -255,6 +255,7 @@ struct ndctl_cmd { > int dir; > } iter; > struct ndctl_cmd *source; > + int (*handle_error)(struct ndctl_cmd *cmd); > union { > struct nd_cmd_ars_cap ars_cap[0]; > struct nd_cmd_ars_start ars_start[0];
diff --git a/ndctl/lib/intel.c b/ndctl/lib/intel.c index 0abea1e..83f8203 100644 --- a/ndctl/lib/intel.c +++ b/ndctl/lib/intel.c @@ -56,6 +56,38 @@ static struct ndctl_cmd *alloc_intel_cmd(struct ndctl_dimm *dimm, return cmd; } +/* + * If provided, read the cached shutdown count in case the user does not have + * access rights to run the smart command, and pretend the command was + * successful with only the shutdown_count valid. + */ +static int intel_smart_handle_error(struct ndctl_cmd *cmd) +{ + struct ndctl_dimm *dimm = cmd->dimm; + char *path = NULL, shutdown_count[16] = {}; + int fd, rc = cmd->status; + + if (asprintf(&path, DEF_TMPFS_DIR "/%s/usc", + ndctl_dimm_get_unique_id(dimm)) < 0) + return rc; + + fd = open(path, O_RDONLY); + if (fd < 0) + goto free_path; + + if (read(fd, shutdown_count, sizeof(shutdown_count)) < 0) + goto close; + + cmd->intel->smart.flags = ND_INTEL_SMART_SHUTDOWN_COUNT_VALID; + cmd->intel->smart.shutdown_count = strtoull(shutdown_count, NULL, 0); + rc = cmd->status = 0; + close: + close (fd); + free_path: + free(path); + return rc; +} + static struct ndctl_cmd *intel_dimm_cmd_new_smart(struct ndctl_dimm *dimm) { struct ndctl_cmd *cmd; @@ -67,7 +99,7 @@ static struct ndctl_cmd *intel_dimm_cmd_new_smart(struct ndctl_dimm *dimm) if (!cmd) return NULL; cmd->firmware_status = &cmd->intel->smart.status; - + cmd->handle_error = intel_smart_handle_error; return cmd; } diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c index 47e005e..d94321e 100644 --- a/ndctl/lib/libndctl.c +++ b/ndctl/lib/libndctl.c @@ -2651,6 +2651,8 @@ NDCTL_EXPORT int ndctl_cmd_submit(struct ndctl_cmd *cmd) close(fd); out: cmd->status = rc; + if (rc && cmd->handle_error) + rc = cmd->handle_error(cmd); return rc; } diff --git a/ndctl/lib/private.h b/ndctl/lib/private.h index a94f894..5812c85 100644 --- a/ndctl/lib/private.h +++ b/ndctl/lib/private.h @@ -255,6 +255,7 @@ struct ndctl_cmd { int dir; } iter; struct ndctl_cmd *source; + int (*handle_error)(struct ndctl_cmd *cmd); union { struct nd_cmd_ars_cap ars_cap[0]; struct nd_cmd_ars_start ars_start[0];
A user space rule saves the unsafe shutdown count to a fixed location for Intel dimms so that non-root users can read it. If the smart command submission fails, this patch uses that saved value in a newly added ndctl_cmd "handle_error" callback. If the cached value is available, the error handler will override the command status to success, and set the valid flags for the shutdown count. Signed-off-by: Keith Busch <keith.busch@intel.com> --- ndctl/lib/intel.c | 34 +++++++++++++++++++++++++++++++++- ndctl/lib/libndctl.c | 2 ++ ndctl/lib/private.h | 1 + 3 files changed, 36 insertions(+), 1 deletion(-)