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writeback: only use bdi_writeback_all() for WB_SYNC_NONE writeout 

Data integrity writeback must use bdi_start_writeback() and ensure
that wbc->sb and wbc->bdi are set.

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2009-09-15 09:53:35 +02:00
parent 32a88aa1b6
commit f11fcae840
1 changed files with 14 additions and 56 deletions
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70
fs/fs-writeback.c
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@ -50,7 +50,6 @@ struct wb_writeback_args {
*/
struct bdi_work {
struct list_head list;
struct list_head wait_list;
struct rcu_head rcu_head;
unsigned long seen;
@ -198,7 +197,8 @@ static void bdi_wait_on_work_clear(struct bdi_work *work)
TASK_UNINTERRUPTIBLE);
}
static struct bdi_work *bdi_alloc_work(struct writeback_control *wbc)
static void bdi_alloc_queue_work(struct backing_dev_info *bdi,
struct writeback_control *wbc)
{
struct bdi_work *work;
@ -206,7 +206,7 @@ static struct bdi_work *bdi_alloc_work(struct writeback_control *wbc)
if (work)
bdi_work_init(work, wbc);
return work;
bdi_queue_work(bdi, work);
}
void bdi_start_writeback(struct writeback_control *wbc)
@ -216,11 +216,9 @@ void bdi_start_writeback(struct writeback_control *wbc)
* bdi_queue_work() will wake up the thread and flush old data. This
* should ensure some amount of progress in freeing memory.
*/
if (wbc->sync_mode != WB_SYNC_ALL) {
struct bdi_work *w = bdi_alloc_work(wbc);
bdi_queue_work(wbc->bdi, w);
} else {
if (wbc->sync_mode != WB_SYNC_ALL)
bdi_alloc_queue_work(wbc->bdi, wbc);
else {
struct bdi_work work;
bdi_work_init(&work, wbc);
@ -860,67 +858,26 @@ int bdi_writeback_task(struct bdi_writeback *wb)
}
/*
* Schedule writeback for all backing devices. Expensive! If this is a data
* integrity operation, writeback will be complete when this returns. If
* we are simply called for WB_SYNC_NONE, then writeback will merely be
* scheduled to run.
* Schedule writeback for all backing devices. Can only be used for
* WB_SYNC_NONE writeback, WB_SYNC_ALL should use bdi_start_writeback()
* and pass in the superblock.
*/
static void bdi_writeback_all(struct writeback_control *wbc)
{
const bool must_wait = wbc->sync_mode == WB_SYNC_ALL;
struct backing_dev_info *bdi;
struct bdi_work *work;
LIST_HEAD(list);
restart:
WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
spin_lock(&bdi_lock);
list_for_each_entry(bdi, &bdi_list, bdi_list) {
struct bdi_work *work;
if (!bdi_has_dirty_io(bdi))
continue;
/*
* If work allocation fails, do the writes inline. We drop
* the lock and restart the list writeout. This should be OK,
* since this happens rarely and because the writeout should
* eventually make more free memory available.
*/
work = bdi_alloc_work(wbc);
if (!work) {
struct writeback_control __wbc;
/*
* Not a data integrity writeout, just continue
*/
if (!must_wait)
continue;
spin_unlock(&bdi_lock);
__wbc = *wbc;
__wbc.bdi = bdi;
writeback_inodes_wbc(&__wbc);
goto restart;
}
if (must_wait)
list_add_tail(&work->wait_list, &list);
bdi_queue_work(bdi, work);
bdi_alloc_queue_work(bdi, wbc);
}
spin_unlock(&bdi_lock);
/*
* If this is for WB_SYNC_ALL, wait for pending work to complete
* before returning.
*/
while (!list_empty(&list)) {
work = list_entry(list.next, struct bdi_work, wait_list);
list_del(&work->wait_list);
bdi_wait_on_work_clear(work);
call_rcu(&work->rcu_head, bdi_work_free);
}
}
/*
@ -1177,6 +1134,7 @@ long sync_inodes_sb(struct super_block *sb)
{
struct writeback_control wbc = {
.sb = sb,
.bdi = sb->s_bdi,
.sync_mode = WB_SYNC_ALL,
.range_start = 0,
.range_end = LLONG_MAX,
@ -1184,7 +1142,7 @@ long sync_inodes_sb(struct super_block *sb)
long nr_to_write = LONG_MAX; /* doesn't actually matter */
wbc.nr_to_write = nr_to_write;
bdi_writeback_all(&wbc);
bdi_start_writeback(&wbc);
wait_sb_inodes(&wbc);
return nr_to_write - wbc.nr_to_write;
}