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- Add kern.cam.ada.X.write_cache tunables/sysctls to control write caching

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on per-device basis.
- While adding support for per-device sysctls, merge from graid branch
support for ADA_TEST_FAILURE kernel option, which opens few more sysctl,
allowing to simulate read and write errors for testing purposes.
This commit is contained in:
mav 2011-04-08 14:42:29 +00:00
parent cd5ddda20d
commit 6028082f68
3 changed files with 105 additions and 12 deletions
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18
share/man/man4/ada.4
View File

@ -25,7 +25,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd April 7, 2011
.Dd April 8, 2011
.Dt ADA 4
.Os
.Sh NAME
@ -101,7 +101,7 @@ variables and
.Xr loader 8
tunables:
.Bl -tag -width 12
.It kern.cam.ada.retry_count
.It Va kern.cam.ada.retry_count
.Pp
This variable determines how many times the
.Nm
@ -111,23 +111,27 @@ the
.Nm
driver dump routine.
This value currently defaults to 4.
.It kern.cam.ada.default_timeout
.It Va kern.cam.ada.default_timeout
.Pp
This variable determines how long the
.Nm
driver will wait before timing out an outstanding command.
The units for this value are seconds, and the default is currently 30
seconds.
.It kern.cam.ada.spindown_shutdown
.It Va kern.cam.ada.spindown_shutdown
.Pp
This variable determines whether to spin-down disks when shutting down.
Set to 1 to enable spin-down, 0 to disable.
The default is currently enabled.
.It kern.cam.ada.write_cache
.It Va kern.cam.ada.write_cache
.It Va kern.cam.ada. Ns Ar X Ns Va .write_cache
.Pp
This variable determines whether device write cache should be enabled or not.
These variables determines whether device write cache should be enabled
globally or per-device or disabled.
Set to 1 to enable write cache, 0 to disable, -1 to leave it as-is.
The default is currently enabled.
Values modified in runtime take effect only after device reset.
The global default is currently enabled.
The per-device default is to leave it as-is (follow global setting).
.El
.Sh FILES
.Bl -tag -width ".Pa /dev/ada*" -compact

96
sys/cam/ata/ata_da.c
View File

@ -27,6 +27,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ada.h"
#include <sys/param.h>
#ifdef _KERNEL
@ -127,6 +129,13 @@ struct ada_softc {
int outstanding_cmds;
int trim_max_ranges;
int trim_running;
int write_cache;
#ifdef ADA_TEST_FAILURE
int force_read_error;
int force_write_error;
int periodic_read_error;
int periodic_read_count;
#endif
struct disk_params params;
struct disk *disk;
struct task sysctl_task;
@ -618,11 +627,11 @@ adaasync(void *callback_arg, u_int32_t code,
softc = (struct ada_softc *)periph->softc;
cam_periph_async(periph, code, path, arg);
if (ada_write_cache < 0)
if (ada_write_cache < 0 && softc->write_cache < 0)
break;
if (softc->state != ADA_STATE_NORMAL)
break;
xpt_setup_ccb(&cgd.ccb_h, path, CAM_PRIORITY_NORMAL);
xpt_setup_ccb(&cgd.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
cgd.ccb_h.func_code = XPT_GDEV_TYPE;
xpt_action((union ccb *)&cgd);
if ((cgd.ident_data.support.command1 & ATA_SUPPORT_WRITECACHE) == 0)
@ -647,8 +656,12 @@ adasysctlinit(void *context, int pending)
char tmpstr[80], tmpstr2[80];
periph = (struct cam_periph *)context;
if (cam_periph_acquire(periph) != CAM_REQ_CMP)
/* periph was held for us when this task was enqueued */
if (periph->flags & CAM_PERIPH_INVALID) {
cam_periph_release(periph);
return;
}
softc = (struct ada_softc *)periph->softc;
snprintf(tmpstr, sizeof(tmpstr), "CAM ADA unit %d", periph->unit_number);
@ -665,6 +678,28 @@ adasysctlinit(void *context, int pending)
return;
}
SYSCTL_ADD_INT(&softc->sysctl_ctx, SYSCTL_CHILDREN(softc->sysctl_tree),
OID_AUTO, "write_cache", CTLFLAG_RW | CTLFLAG_MPSAFE,
&softc->write_cache, 0, "Enable disk write cache.");
#ifdef ADA_TEST_FAILURE
/*
* Add a 'door bell' sysctl which allows one to set it from userland
* and cause something bad to happen. For the moment, we only allow
* whacking the next read or write.
*/
SYSCTL_ADD_INT(&softc->sysctl_ctx, SYSCTL_CHILDREN(softc->sysctl_tree),
OID_AUTO, "force_read_error", CTLFLAG_RW | CTLFLAG_MPSAFE,
&softc->force_read_error, 0,
"Force a read error for the next N reads.");
SYSCTL_ADD_INT(&softc->sysctl_ctx, SYSCTL_CHILDREN(softc->sysctl_tree),
OID_AUTO, "force_write_error", CTLFLAG_RW | CTLFLAG_MPSAFE,
&softc->force_write_error, 0,
"Force a write error for the next N writes.");
SYSCTL_ADD_INT(&softc->sysctl_ctx, SYSCTL_CHILDREN(softc->sysctl_tree),
OID_AUTO, "periodic_read_error", CTLFLAG_RW | CTLFLAG_MPSAFE,
&softc->periodic_read_error, 0,
"Force a read error every N reads (don't set too low).");
#endif
cam_periph_release(periph);
}
@ -738,6 +773,10 @@ adaregister(struct cam_periph *periph, void *arg)
softc->quirks = ((struct ada_quirk_entry *)match)->quirks;
else
softc->quirks = ADA_Q_NONE;
softc->write_cache = -1;
snprintf(announce_buf, sizeof(announce_buf),
"kern.cam.ada.%d.writa_cache", periph->unit_number);
TUNABLE_INT_FETCH(announce_buf, &softc->write_cache);
bzero(&cpi, sizeof(cpi));
xpt_setup_ccb(&cpi.ccb_h, periph->path, CAM_PRIORITY_NONE);
@ -812,6 +851,14 @@ adaregister(struct cam_periph *periph, void *arg)
dp->secsize, dp->heads,
dp->secs_per_track, dp->cylinders);
xpt_announce_periph(periph, announce_buf);
/*
* Create our sysctl variables, now that we know
* we have successfully attached.
*/
cam_periph_acquire(periph);
taskqueue_enqueue(taskqueue_thread, &softc->sysctl_task);
/*
* Add async callbacks for bus reset and
* bus device reset calls. I don't bother
@ -832,7 +879,7 @@ adaregister(struct cam_periph *periph, void *arg)
(ADA_DEFAULT_TIMEOUT * hz) / ADA_ORDEREDTAG_INTERVAL,
adasendorderedtag, softc);
if (ada_write_cache >= 0 &&
if ((ada_write_cache >= 0 || softc->write_cache >= 0) &&
cgd->ident_data.support.command1 & ATA_SUPPORT_WRITECACHE) {
softc->state = ADA_STATE_WCACHE;
cam_periph_acquire(periph);
@ -944,7 +991,45 @@ adastart(struct cam_periph *periph, union ccb *start_ccb)
{
uint64_t lba = bp->bio_pblkno;
uint16_t count = bp->bio_bcount / softc->params.secsize;
#ifdef ADA_TEST_FAILURE
int fail = 0;
/*
* Support the failure ioctls. If the command is a
* read, and there are pending forced read errors, or
* if a write and pending write errors, then fail this
* operation with EIO. This is useful for testing
* purposes. Also, support having every Nth read fail.
*
* This is a rather blunt tool.
*/
if (bp->bio_cmd == BIO_READ) {
if (softc->force_read_error) {
softc->force_read_error--;
fail = 1;
}
if (softc->periodic_read_error > 0) {
if (++softc->periodic_read_count >=
softc->periodic_read_error) {
softc->periodic_read_count = 0;
fail = 1;
}
}
} else {
if (softc->force_write_error) {
softc->force_write_error--;
fail = 1;
}
}
if (fail) {
bp->bio_error = EIO;
bp->bio_flags |= BIO_ERROR;
biodone(bp);
xpt_release_ccb(start_ccb);
adaschedule(periph);
return;
}
#endif
cam_fill_ataio(ataio,
ada_retry_count,
adadone,
@ -1062,7 +1147,8 @@ adastart(struct cam_periph *periph, union ccb *start_ccb)
0,
ada_default_timeout*1000);
ata_28bit_cmd(ataio, ATA_SETFEATURES, ada_write_cache ?
ata_28bit_cmd(ataio, ATA_SETFEATURES, (softc->write_cache > 0 ||
(softc->write_cache < 0 && ada_write_cache)) ?
ATA_SF_ENAB_WCACHE : ATA_SF_DIS_WCACHE, 0, 0);
start_ccb->ccb_h.ccb_state = ADA_CCB_WCACHE;
xpt_action(start_ccb);

3
sys/conf/options
View File

@ -305,6 +305,9 @@ SCSI_DELAY opt_scsi.h
SCSI_NO_SENSE_STRINGS opt_scsi.h
SCSI_NO_OP_STRINGS opt_scsi.h
# Options used only in cam/ata/ata_da.c
ADA_TEST_FAILURE opt_ada.h
# Options used only in cam/scsi/scsi_cd.c
CHANGER_MIN_BUSY_SECONDS opt_cd.h
CHANGER_MAX_BUSY_SECONDS opt_cd.h