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#include "bcache.h"
#include "error.h"
#include "io.h"
#include "notify.h"
#include "super.h"
void bch_inconsistent_error(struct cache_set *c)
{
set_bit(CACHE_SET_ERROR, &c->flags);
switch (c->opts.errors) {
case BCH_ON_ERROR_CONTINUE:
break;
case BCH_ON_ERROR_RO:
if (!test_bit(CACHE_SET_INITIAL_GC_DONE, &c->flags)) {
/* XXX do something better here? */
bch_cache_set_stop(c);
return;
}
if (bch_cache_set_emergency_read_only(c))
bch_err(c, "emergency read only");
break;
case BCH_ON_ERROR_PANIC:
panic(bch_fmt(c, "panic after error"));
break;
}
}
void bch_fatal_error(struct cache_set *c)
{
if (bch_cache_set_emergency_read_only(c))
bch_err(c, "emergency read only");
}
/* Nonfatal IO errors, IO error/latency accounting: */
/* Just does IO error accounting: */
void bch_account_io_completion(struct cache *ca)
{
/*
* The halflife of an error is:
* log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
*/
if (ca->set->error_decay) {
unsigned count = atomic_inc_return(&ca->io_count);
while (count > ca->set->error_decay) {
unsigned errors;
unsigned old = count;
unsigned new = count - ca->set->error_decay;
/*
* First we subtract refresh from count; each time we
* succesfully do so, we rescale the errors once:
*/
count = atomic_cmpxchg(&ca->io_count, old, new);
if (count == old) {
count = new;
errors = atomic_read(&ca->io_errors);
do {
old = errors;
new = ((uint64_t) errors * 127) / 128;
errors = atomic_cmpxchg(&ca->io_errors,
old, new);
} while (old != errors);
}
}
}
}
/* IO error accounting and latency accounting: */
void bch_account_io_completion_time(struct cache *ca,
unsigned submit_time_us, int op)
{
struct cache_set *c;
unsigned threshold;
if (!ca)
return;
c = ca->set;
threshold = op_is_write(op)
? c->congested_write_threshold_us
: c->congested_read_threshold_us;
if (threshold && submit_time_us) {
unsigned t = local_clock_us();
int us = t - submit_time_us;
int congested = atomic_read(&c->congested);
if (us > (int) threshold) {
int ms = us / 1024;
c->congested_last_us = t;
ms = min(ms, CONGESTED_MAX + congested);
atomic_sub(ms, &c->congested);
} else if (congested < 0)
atomic_inc(&c->congested);
}
bch_account_io_completion(ca);
}
void bch_nonfatal_io_error_work(struct work_struct *work)
{
struct cache *ca = container_of(work, struct cache, io_error_work);
struct cache_set *c = ca->set;
unsigned errors = atomic_read(&ca->io_errors);
char buf[BDEVNAME_SIZE];
bool dev;
if (errors < c->error_limit) {
bch_notify_cache_error(ca, false);
} else {
bch_notify_cache_error(ca, true);
mutex_lock(&bch_register_lock);
dev = bch_cache_may_remove(ca);
if (dev
? bch_cache_read_only(ca)
: bch_cache_set_emergency_read_only(c))
bch_err(c,
"too many IO errors on %s, setting %s RO",
bdevname(ca->disk_sb.bdev, buf),
dev ? "device" : "filesystem");
mutex_unlock(&bch_register_lock);
}
}
void bch_nonfatal_io_error(struct cache *ca)
{
atomic_add(1 << IO_ERROR_SHIFT, &ca->io_errors);
queue_work(system_long_wq, &ca->io_error_work);
}
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