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aio: finally fix race on dirty area at the end

This commit is contained in:
Thomas Schoebel-Theuer 2013-07-03 12:43:58 +02:00
parent 83b75845c3
commit 62e2f5944b
2 changed files with 70 additions and 13 deletions
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78
kernel/mars_aio.c
View File

@ -131,6 +131,51 @@ done:
return mref_a;
}
////////////////// dirty IOs on the fly //////////////////
static inline
void insert_dirty(struct aio_output *output, struct aio_mref_aspect *mref_a)
{
unsigned long flags = 0;
traced_lock(&output->dirty_lock, flags);
list_del(&mref_a->dirty_head);
list_add(&mref_a->dirty_head, &output->dirty_anchor);
traced_unlock(&output->dirty_lock, flags);
}
static inline
void remove_dirty(struct aio_output *output, struct aio_mref_aspect *mref_a)
{
if (!list_empty(&mref_a->dirty_head)) {
unsigned long flags = 0;
traced_lock(&output->dirty_lock, flags);
list_del_init(&mref_a->dirty_head);
traced_unlock(&output->dirty_lock, flags);
}
}
static inline
void get_dirty(struct aio_output *output, loff_t *min, loff_t *max)
{
struct list_head *tmp;
unsigned long flags = 0;
traced_lock(&output->dirty_lock, flags);
for (tmp = output->dirty_anchor.next; tmp != &output->dirty_anchor; tmp = tmp->next) {
struct aio_mref_aspect *mref_a = container_of(tmp, struct aio_mref_aspect, dirty_head);
struct mref_object *mref = mref_a->object;
if (mref->ref_pos < *min) {
*min = mref->ref_pos;
}
if (mref->ref_pos + mref->ref_len > *max) {
*max = mref->ref_pos + mref->ref_len;
}
}
traced_unlock(&output->dirty_lock, flags);
}
////////////////// own brick / input / output operations //////////////////
static int aio_ref_get(struct aio_output *output, struct mref_object *mref)
@ -259,11 +304,7 @@ void _complete(struct aio_output *output, struct mref_object *mref, int err)
done:
if (mref->ref_rw) {
struct file *file = output->mf->mf_filp;
loff_t new_size = i_size_read(file->f_mapping->host);
if (atomic_dec_and_test(&output->write_count)) {
output->old_size = new_size;
}
atomic_dec(&output->write_count);
} else {
atomic_dec(&output->read_count);
}
@ -284,6 +325,7 @@ void _complete_all(struct list_head *tmp_list, struct aio_output *output, int er
struct list_head *tmp = tmp_list->next;
struct aio_mref_aspect *mref_a = container_of(tmp, struct aio_mref_aspect, io_head);
list_del_init(tmp);
remove_dirty(output, mref_a);
_complete(output, mref_a->object, err);
}
}
@ -781,6 +823,10 @@ static int aio_submit_thread(void *data)
mapfree_set(output->mf, mref->ref_pos, -1);
if (mref->ref_rw) {
insert_dirty(output, mref_a);
}
// check for reads exactly at EOF (special case)
if (mref->ref_pos == mref->ref_total_size &&
!mref->ref_rw &&
@ -842,6 +888,9 @@ static int aio_submit_thread(void *data)
static int aio_get_info(struct aio_output *output, struct mars_info *info)
{
struct file *file;
loff_t min;
loff_t max;
if (unlikely(!output ||
!output->mf ||
!(file = output->mf->mf_filp) ||
@ -860,16 +909,16 @@ static int aio_get_info(struct aio_output *output, struct mars_info *info)
* appended by a write operation, but the data has not actually hit
* the page cache, such that a concurrent read gets NULL blocks.
*/
if (atomic_read(&output->write_count) > 0 && output->old_size > 0) {
info->current_size = output->old_size;
MARS_DBG("using old file size = %lld\n", info->current_size);
return 0;
min = i_size_read(file->f_mapping->host);
max = 0;
if (!output->brick->is_static_device) {
get_dirty(output, &min, &max);
}
info->current_size = i_size_read(file->f_mapping->host);
info->current_size = min;
MARS_DBG("determined file size = %lld\n", info->current_size);
output->old_size = info->current_size;
return 0;
}
@ -969,13 +1018,15 @@ static int aio_mref_aspect_init_fn(struct generic_aspect *_ini)
{
struct aio_mref_aspect *ini = (void*)_ini;
INIT_LIST_HEAD(&ini->io_head);
INIT_LIST_HEAD(&ini->dirty_head);
return 0;
}
static void aio_mref_aspect_exit_fn(struct generic_aspect *_ini)
{
struct aio_mref_aspect *ini = (void*)_ini;
(void)ini;
CHECK_HEAD_EMPTY(&ini->dirty_head);
CHECK_HEAD_EMPTY(&ini->io_head);
}
MARS_MAKE_STATICS(aio);
@ -1070,12 +1121,15 @@ cleanup:
static int aio_output_construct(struct aio_output *output)
{
INIT_LIST_HEAD(&output->dirty_anchor);
spin_lock_init(&output->dirty_lock);
init_waitqueue_head(&output->fdsync_event);
return 0;
}
static int aio_output_destruct(struct aio_output *output)
{
CHECK_HEAD_EMPTY(&output->dirty_anchor);
return 0;
}

5
kernel/mars_aio.h
View File

@ -24,6 +24,7 @@ extern int aio_sync_mode;
struct aio_mref_aspect {
GENERIC_ASPECT(mref);
struct list_head io_head;
struct list_head dirty_head;
unsigned long long enqueue_stamp;
long long start_jiffies;
int resubmit;
@ -37,6 +38,7 @@ struct aio_brick {
bool o_creat;
bool o_direct;
bool o_fdsync;
bool is_static_device;
};
struct aio_input {
@ -59,10 +61,11 @@ struct aio_threadinfo {
struct aio_output {
MARS_OUTPUT(aio);
// private
struct list_head dirty_anchor;
spinlock_t dirty_lock;
struct mapfree_info *mf;
int fd; // FIXME: remove this!
struct aio_threadinfo tinfo[3];
loff_t old_size;
aio_context_t ctxp;
wait_queue_head_t fdsync_event;
bool fdsync_active;