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ANDROID: dm verity fec: add sysfs attribute fec/corrected

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Add a sysfs entry that allows user space to determine whether dm-verity
has come across correctable errors on the underlying block device.

Bug: 22655252
Bug: 27928374
Change-Id: I80547a2aa944af2fb9ffde002650482877ade31b
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
(cherry picked from commit 7911fad5f0a2cf5afc2215657219a21e6630e001)
This commit is contained in:
Sami Tolvanen 2016-03-30 14:10:13 -07:00
parent fcd614efb6
commit e7d40d2bf8
2 changed files with 47 additions and 1 deletions
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45
drivers/md/dm-verity-fec.c
View file

@ -11,6 +11,7 @@
#include "dm-verity-fec.h"
#include <linux/math64.h>
#include <linux/sysfs.h>
#define DM_MSG_PREFIX "verity-fec"
@ -175,9 +176,11 @@ error:
if (r < 0 && neras)
DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",
v->data_dev->name, (unsigned long long)rsb, r);
else if (r > 0)
else if (r > 0) {
DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",
v->data_dev->name, (unsigned long long)rsb, r);
atomic_add_unless(&v->fec->corrected, 1, INT_MAX);
}
return r;
}
@ -548,6 +551,7 @@ unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz,
void verity_fec_dtr(struct dm_verity *v)
{
struct dm_verity_fec *f = v->fec;
struct kobject *kobj = &f->kobj_holder.kobj;
if (!verity_fec_is_enabled(v))
goto out;
@ -564,6 +568,12 @@ void verity_fec_dtr(struct dm_verity *v)
if (f->dev)
dm_put_device(v->ti, f->dev);
if (kobj->state_initialized) {
kobject_put(kobj);
wait_for_completion(dm_get_completion_from_kobject(kobj));
}
out:
kfree(f);
v->fec = NULL;
@ -652,6 +662,27 @@ int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
return 0;
}
static ssize_t corrected_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct dm_verity_fec *f = container_of(kobj, struct dm_verity_fec,
kobj_holder.kobj);
return sprintf(buf, "%d\n", atomic_read(&f->corrected));
}
static struct kobj_attribute attr_corrected = __ATTR_RO(corrected);
static struct attribute *fec_attrs[] = {
&attr_corrected.attr,
NULL
};
static struct kobj_type fec_ktype = {
.sysfs_ops = &kobj_sysfs_ops,
.default_attrs = fec_attrs
};
/*
* Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr.
*/
@ -675,8 +706,10 @@ int verity_fec_ctr_alloc(struct dm_verity *v)
*/
int verity_fec_ctr(struct dm_verity *v)
{
int r;
struct dm_verity_fec *f = v->fec;
struct dm_target *ti = v->ti;
struct mapped_device *md = dm_table_get_md(ti->table);
u64 hash_blocks;
if (!verity_fec_is_enabled(v)) {
@ -684,6 +717,16 @@ int verity_fec_ctr(struct dm_verity *v)
return 0;
}
/* Create a kobject and sysfs attributes */
init_completion(&f->kobj_holder.completion);
r = kobject_init_and_add(&f->kobj_holder.kobj, &fec_ktype,
&disk_to_dev(dm_disk(md))->kobj, "%s", "fec");
if (r) {
ti->error = "Cannot create kobject";
return r;
}
/*
* FEC is computed over data blocks, possible metadata, and
* hash blocks. In other words, FEC covers total of fec_blocks

3
drivers/md/dm-verity-fec.h
View file

@ -12,6 +12,7 @@
#ifndef DM_VERITY_FEC_H
#define DM_VERITY_FEC_H
#include "dm.h"
#include "dm-verity.h"
#include <linux/rslib.h>
@ -48,6 +49,8 @@ struct dm_verity_fec {
mempool_t *extra_pool; /* mempool for extra buffers */
mempool_t *output_pool; /* mempool for output */
struct kmem_cache *cache; /* cache for buffers */
atomic_t corrected; /* corrected errors */
struct dm_kobject_holder kobj_holder; /* for sysfs attributes */
};
/* per-bio data */