ANDROID: dm verity fec: add sysfs attribute fec/corrected
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)
diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
index 0f0eb8a..0e79f38 100644
--- a/drivers/md/dm-verity-fec.c
+++ b/drivers/md/dm-verity-fec.c
@@ -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 @@
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;
}
@@ -546,6 +549,7 @@
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;
@@ -562,6 +566,12 @@
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;
@@ -650,6 +660,27 @@
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.
*/
@@ -673,8 +704,10 @@
*/
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)) {
@@ -682,6 +715,16 @@
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
diff --git a/drivers/md/dm-verity-fec.h b/drivers/md/dm-verity-fec.h
index 7fa0298..a22098d 100644
--- a/drivers/md/dm-verity-fec.h
+++ b/drivers/md/dm-verity-fec.h
@@ -12,6 +12,8 @@
#ifndef DM_VERITY_FEC_H
#define DM_VERITY_FEC_H
+#include "dm.h"
+#include "dm-core.h"
#include "dm-verity.h"
#include <linux/rslib.h>
@@ -48,6 +50,8 @@
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 */