long nr_pages;
struct super_block *sb;
enum writeback_sync_modes sync_mode;
+ unsigned int tagged_writepages:1;
unsigned int for_kupdate:1;
unsigned int range_cyclic:1;
unsigned int for_background:1;
#define CREATE_TRACE_POINTS
#include <trace/events/writeback.h>
-#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info)
-
/*
* We don't actually have pdflush, but this one is exported though /proc...
*/
*/
int writeback_in_progress(struct backing_dev_info *bdi)
{
- return !list_empty(&bdi->work_list);
+ return test_bit(BDI_writeback_running, &bdi->state);
+}
+
+static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+
+ if (strcmp(sb->s_type->name, "bdev") == 0)
+ return inode->i_mapping->backing_dev_info;
+
+ return sb->s_bdi;
+}
+
+static inline struct inode *wb_inode(struct list_head *head)
+{
+ return list_entry(head, struct inode, i_wb_list);
+}
+
+/* Wakeup flusher thread or forker thread to fork it. Requires bdi->wb_lock. */
+static void bdi_wakeup_flusher(struct backing_dev_info *bdi)
+{
+ if (bdi->wb.task) {
+ wake_up_process(bdi->wb.task);
+ } else {
+ /*
+ * The bdi thread isn't there, wake up the forker thread which
+ * will create and run it.
+ */
+ wake_up_process(default_backing_dev_info.wb.task);
+ }
}
static void bdi_queue_work(struct backing_dev_info *bdi,
- struct wb_writeback_work *work)
+ struct wb_writeback_work *work)
{
trace_writeback_queue(bdi, work);
- spin_lock(&bdi->wb_lock);
+ spin_lock_bh(&bdi->wb_lock);
list_add_tail(&work->list, &bdi->work_list);
- spin_unlock(&bdi->wb_lock);
-
- /*
- * If the default thread isn't there, make sure we add it. When
- * it gets created and wakes up, we'll run this work.
- */
- if (unlikely(!bdi->wb.task)) {
+ if (!bdi->wb.task)
trace_writeback_nothread(bdi, work);
- wake_up_process(default_backing_dev_info.wb.task);
- } else {
- struct bdi_writeback *wb = &bdi->wb;
-
- if (wb->task)
- wake_up_process(wb->task);
- }
+ bdi_wakeup_flusher(bdi);
+ spin_unlock_bh(&bdi->wb_lock);
}
static void
__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
- bool range_cyclic, bool for_background)
+ bool range_cyclic)
{
struct wb_writeback_work *work;
work->sync_mode = WB_SYNC_NONE;
work->nr_pages = nr_pages;
work->range_cyclic = range_cyclic;
- work->for_background = for_background;
bdi_queue_work(bdi, work);
}
*
* Description:
* This does WB_SYNC_NONE opportunistic writeback. The IO is only
- * started when this function returns, we make no guarentees on
+ * started when this function returns, we make no guarantees on
* completion. Caller need not hold sb s_umount semaphore.
*
*/
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
{
- __bdi_start_writeback(bdi, nr_pages, true, false);
+ __bdi_start_writeback(bdi, nr_pages, true);
}
/**
* @bdi: the backing device to write from
*
* Description:
- * This does WB_SYNC_NONE background writeback. The IO is only
- * started when this function returns, we make no guarentees on
- * completion. Caller need not hold sb s_umount semaphore.
+ * This makes sure WB_SYNC_NONE background writeback happens. When
+ * this function returns, it is only guaranteed that for given BDI
+ * some IO is happening if we are over background dirty threshold.
+ * Caller need not hold sb s_umount semaphore.
*/
void bdi_start_background_writeback(struct backing_dev_info *bdi)
{
- __bdi_start_writeback(bdi, LONG_MAX, true, true);
+ /*
+ * We just wake up the flusher thread. It will perform background
+ * writeback as soon as there is no other work to do.
+ */
+ trace_writeback_wake_background(bdi);
+ spin_lock_bh(&bdi->wb_lock);
+ bdi_wakeup_flusher(bdi);
+ spin_unlock_bh(&bdi->wb_lock);
}
+/*
+ * Remove the inode from the writeback list it is on.
+ */
+void inode_wb_list_del(struct inode *inode)
+{
+ spin_lock(&inode_wb_list_lock);
+ list_del_init(&inode->i_wb_list);
+ spin_unlock(&inode_wb_list_lock);
+}
+
+
/*
* Redirty an inode: set its when-it-was dirtied timestamp and move it to the
* furthest end of its superblock's dirty-inode list.
{
struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
+ assert_spin_locked(&inode_wb_list_lock);
if (!list_empty(&wb->b_dirty)) {
struct inode *tail;
- tail = list_entry(wb->b_dirty.next, struct inode, i_list);
+ tail = wb_inode(wb->b_dirty.next);
if (time_before(inode->dirtied_when, tail->dirtied_when))
inode->dirtied_when = jiffies;
}
- list_move(&inode->i_list, &wb->b_dirty);
+ list_move(&inode->i_wb_list, &wb->b_dirty);
}
/*
{
struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
- list_move(&inode->i_list, &wb->b_more_io);
+ assert_spin_locked(&inode_wb_list_lock);
+ list_move(&inode->i_wb_list, &wb->b_more_io);
}
static void inode_sync_complete(struct inode *inode)
{
/*
- * Prevent speculative execution through spin_unlock(&inode_lock);
+ * Prevent speculative execution through
+ * spin_unlock(&inode_wb_list_lock);
*/
+
smp_mb();
wake_up_bit(&inode->i_state, __I_SYNC);
}
int do_sb_sort = 0;
while (!list_empty(delaying_queue)) {
- inode = list_entry(delaying_queue->prev, struct inode, i_list);
+ inode = wb_inode(delaying_queue->prev);
if (older_than_this &&
inode_dirtied_after(inode, *older_than_this))
break;
if (sb && sb != inode->i_sb)
do_sb_sort = 1;
sb = inode->i_sb;
- list_move(&inode->i_list, &tmp);
+ list_move(&inode->i_wb_list, &tmp);
}
/* just one sb in list, splice to dispatch_queue and we're done */
/* Move inodes from one superblock together */
while (!list_empty(&tmp)) {
- inode = list_entry(tmp.prev, struct inode, i_list);
- sb = inode->i_sb;
+ sb = wb_inode(tmp.prev)->i_sb;
list_for_each_prev_safe(pos, node, &tmp) {
- inode = list_entry(pos, struct inode, i_list);
+ inode = wb_inode(pos);
if (inode->i_sb == sb)
- list_move(&inode->i_list, dispatch_queue);
+ list_move(&inode->i_wb_list, dispatch_queue);
}
}
}
/*
* Queue all expired dirty inodes for io, eldest first.
+ * Before
+ * newly dirtied b_dirty b_io b_more_io
+ * =============> gf edc BA
+ * After
+ * newly dirtied b_dirty b_io b_more_io
+ * =============> g fBAedc
+ * |
+ * +--> dequeue for IO
*/
static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
{
- list_splice_init(&wb->b_more_io, wb->b_io.prev);
+ assert_spin_locked(&inode_wb_list_lock);
+ list_splice_init(&wb->b_more_io, &wb->b_io);
move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
}
wait_queue_head_t *wqh;
wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
- while (inode->i_state & I_SYNC) {
- spin_unlock(&inode_lock);
+ while (inode->i_state & I_SYNC) {
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_wb_list_lock);
__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
- spin_lock(&inode_lock);
+ spin_lock(&inode_wb_list_lock);
+ spin_lock(&inode->i_lock);
}
}
/*
- * Write out an inode's dirty pages. Called under inode_lock. Either the
- * caller has ref on the inode (either via __iget or via syscall against an fd)
- * or the inode has I_WILL_FREE set (via generic_forget_inode)
+ * Write out an inode's dirty pages. Called under inode_wb_list_lock and
+ * inode->i_lock. Either the caller has an active reference on the inode or
+ * the inode has I_WILL_FREE set.
*
* If `wait' is set, wait on the writeout.
*
* The whole writeout design is quite complex and fragile. We want to avoid
* starvation of particular inodes when others are being redirtied, prevent
* livelocks, etc.
- *
- * Called under inode_lock.
*/
static int
writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
unsigned dirty;
int ret;
+ assert_spin_locked(&inode_wb_list_lock);
+ assert_spin_locked(&inode->i_lock);
+
if (!atomic_read(&inode->i_count))
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else
/* Set I_SYNC, reset I_DIRTY_PAGES */
inode->i_state |= I_SYNC;
inode->i_state &= ~I_DIRTY_PAGES;
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_wb_list_lock);
ret = do_writepages(mapping, wbc);
* due to delalloc, clear dirty metadata flags right before
* write_inode()
*/
- spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
dirty = inode->i_state & I_DIRTY;
inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
/* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
int err = write_inode(inode, wbc);
ret = err;
}
- spin_lock(&inode_lock);
+ spin_lock(&inode_wb_list_lock);
+ spin_lock(&inode->i_lock);
inode->i_state &= ~I_SYNC;
- if (!(inode->i_state & (I_FREEING | I_CLEAR))) {
- if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) {
- /*
- * More pages get dirtied by a fast dirtier.
- */
- goto select_queue;
- } else if (inode->i_state & I_DIRTY) {
- /*
- * At least XFS will redirty the inode during the
- * writeback (delalloc) and on io completion (isize).
- */
- redirty_tail(inode);
- } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
+ if (!(inode->i_state & I_FREEING)) {
+ if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
/*
* We didn't write back all the pages. nfs_writepages()
- * sometimes bales out without doing anything. Redirty
- * the inode; Move it from b_io onto b_more_io/b_dirty.
- */
- /*
- * akpm: if the caller was the kupdate function we put
- * this inode at the head of b_dirty so it gets first
- * consideration. Otherwise, move it to the tail, for
- * the reasons described there. I'm not really sure
- * how much sense this makes. Presumably I had a good
- * reasons for doing it this way, and I'd rather not
- * muck with it at present.
+ * sometimes bales out without doing anything.
*/
- if (wbc->for_kupdate) {
+ inode->i_state |= I_DIRTY_PAGES;
+ if (wbc->nr_to_write <= 0) {
/*
- * For the kupdate function we move the inode
- * to b_more_io so it will get more writeout as
- * soon as the queue becomes uncongested.
+ * slice used up: queue for next turn
*/
- inode->i_state |= I_DIRTY_PAGES;
-select_queue:
- if (wbc->nr_to_write <= 0) {
- /*
- * slice used up: queue for next turn
- */
- requeue_io(inode);
- } else {
- /*
- * somehow blocked: retry later
- */
- redirty_tail(inode);
- }
+ requeue_io(inode);
} else {
/*
- * Otherwise fully redirty the inode so that
- * other inodes on this superblock will get some
- * writeout. Otherwise heavy writing to one
- * file would indefinitely suspend writeout of
- * all the other files.
+ * Writeback blocked by something other than
+ * congestion. Delay the inode for some time to
+ * avoid spinning on the CPU (100% iowait)
+ * retrying writeback of the dirty page/inode
+ * that cannot be performed immediately.
*/
- inode->i_state |= I_DIRTY_PAGES;
redirty_tail(inode);
}
- } else if (atomic_read(&inode->i_count)) {
+ } else if (inode->i_state & I_DIRTY) {
/*
- * The inode is clean, inuse
+ * Filesystems can dirty the inode during writeback
+ * operations, such as delayed allocation during
+ * submission or metadata updates after data IO
+ * completion.
*/
- list_move(&inode->i_list, &inode_in_use);
+ redirty_tail(inode);
} else {
/*
- * The inode is clean, unused
+ * The inode is clean. At this point we either have
+ * a reference to the inode or it's on it's way out.
+ * No need to add it back to the LRU.
*/
- list_move(&inode->i_list, &inode_unused);
+ list_del_init(&inode->i_wb_list);
}
}
inode_sync_complete(inode);
{
while (!list_empty(&wb->b_io)) {
long pages_skipped;
- struct inode *inode = list_entry(wb->b_io.prev,
- struct inode, i_list);
+ struct inode *inode = wb_inode(wb->b_io.prev);
if (inode->i_sb != sb) {
if (only_this_sb) {
return 0;
}
- if (inode->i_state & (I_NEW | I_WILL_FREE)) {
+ /*
+ * Don't bother with new inodes or inodes beeing freed, first
+ * kind does not need peridic writeout yet, and for the latter
+ * kind writeout is handled by the freer.
+ */
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+ spin_unlock(&inode->i_lock);
requeue_io(inode);
continue;
}
+
/*
* Was this inode dirtied after sync_sb_inodes was called?
* This keeps sync from extra jobs and livelock.
*/
- if (inode_dirtied_after(inode, wbc->wb_start))
+ if (inode_dirtied_after(inode, wbc->wb_start)) {
+ spin_unlock(&inode->i_lock);
return 1;
+ }
- BUG_ON(inode->i_state & (I_FREEING | I_CLEAR));
__iget(inode);
+
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
if (wbc->pages_skipped != pages_skipped) {
*/
redirty_tail(inode);
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_wb_list_lock);
iput(inode);
cond_resched();
- spin_lock(&inode_lock);
+ spin_lock(&inode_wb_list_lock);
if (wbc->nr_to_write <= 0) {
wbc->more_io = 1;
return 1;
{
int ret = 0;
- wbc->wb_start = jiffies; /* livelock avoidance */
- spin_lock(&inode_lock);
+ if (!wbc->wb_start)
+ wbc->wb_start = jiffies; /* livelock avoidance */
+ spin_lock(&inode_wb_list_lock);
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
while (!list_empty(&wb->b_io)) {
- struct inode *inode = list_entry(wb->b_io.prev,
- struct inode, i_list);
+ struct inode *inode = wb_inode(wb->b_io.prev);
struct super_block *sb = inode->i_sb;
if (!pin_sb_for_writeback(sb)) {
if (ret)
break;
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_wb_list_lock);
/* Leave any unwritten inodes on b_io */
}
{
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- wbc->wb_start = jiffies; /* livelock avoidance */
- spin_lock(&inode_lock);
+ spin_lock(&inode_wb_list_lock);
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
writeback_sb_inodes(sb, wb, wbc, true);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_wb_list_lock);
}
/*
{
unsigned long background_thresh, dirty_thresh;
- get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
+ global_dirty_limits(&background_thresh, &dirty_thresh);
return (global_page_state(NR_FILE_DIRTY) +
- global_page_state(NR_UNSTABLE_NFS) >= background_thresh);
+ global_page_state(NR_UNSTABLE_NFS) > background_thresh);
}
/*
{
struct writeback_control wbc = {
.sync_mode = work->sync_mode,
+ .tagged_writepages = work->tagged_writepages,
.older_than_this = NULL,
.for_kupdate = work->for_kupdate,
.for_background = work->for_background,
};
unsigned long oldest_jif;
long wrote = 0;
+ long write_chunk = MAX_WRITEBACK_PAGES;
struct inode *inode;
if (wbc.for_kupdate) {
wbc.range_end = LLONG_MAX;
}
+ /*
+ * WB_SYNC_ALL mode does livelock avoidance by syncing dirty
+ * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX
+ * here avoids calling into writeback_inodes_wb() more than once.
+ *
+ * The intended call sequence for WB_SYNC_ALL writeback is:
+ *
+ * wb_writeback()
+ * __writeback_inodes_sb() <== called only once
+ * write_cache_pages() <== called once for each inode
+ * (quickly) tag currently dirty pages
+ * (maybe slowly) sync all tagged pages
+ */
+ if (wbc.sync_mode == WB_SYNC_ALL || wbc.tagged_writepages)
+ write_chunk = LONG_MAX;
+
+ wbc.wb_start = jiffies; /* livelock avoidance */
for (;;) {
/*
* Stop writeback when nr_pages has been consumed
if (work->nr_pages <= 0)
break;
+ /*
+ * Background writeout and kupdate-style writeback may
+ * run forever. Stop them if there is other work to do
+ * so that e.g. sync can proceed. They'll be restarted
+ * after the other works are all done.
+ */
+ if ((work->for_background || work->for_kupdate) &&
+ !list_empty(&wb->bdi->work_list))
+ break;
+
/*
* For background writeout, stop when we are below the
* background dirty threshold
break;
wbc.more_io = 0;
- wbc.nr_to_write = MAX_WRITEBACK_PAGES;
+ wbc.nr_to_write = write_chunk;
wbc.pages_skipped = 0;
trace_wbc_writeback_start(&wbc, wb->bdi);
writeback_inodes_wb(wb, &wbc);
trace_wbc_writeback_written(&wbc, wb->bdi);
- work->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
- wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;
+ work->nr_pages -= write_chunk - wbc.nr_to_write;
+ wrote += write_chunk - wbc.nr_to_write;
/*
* If we consumed everything, see if we have more
/*
* Did we write something? Try for more
*/
- if (wbc.nr_to_write < MAX_WRITEBACK_PAGES)
+ if (wbc.nr_to_write < write_chunk)
continue;
/*
* Nothing written. Wait for some inode to
* become available for writeback. Otherwise
* we'll just busyloop.
*/
- spin_lock(&inode_lock);
+ spin_lock(&inode_wb_list_lock);
if (!list_empty(&wb->b_more_io)) {
- inode = list_entry(wb->b_more_io.prev,
- struct inode, i_list);
+ inode = wb_inode(wb->b_more_io.prev);
trace_wbc_writeback_wait(&wbc, wb->bdi);
+ spin_lock(&inode->i_lock);
inode_wait_for_writeback(inode);
+ spin_unlock(&inode->i_lock);
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_wb_list_lock);
}
return wrote;
{
struct wb_writeback_work *work = NULL;
- spin_lock(&bdi->wb_lock);
+ spin_lock_bh(&bdi->wb_lock);
if (!list_empty(&bdi->work_list)) {
work = list_entry(bdi->work_list.next,
struct wb_writeback_work, list);
list_del_init(&work->list);
}
- spin_unlock(&bdi->wb_lock);
+ spin_unlock_bh(&bdi->wb_lock);
return work;
}
+/*
+ * Add in the number of potentially dirty inodes, because each inode
+ * write can dirty pagecache in the underlying blockdev.
+ */
+static unsigned long get_nr_dirty_pages(void)
+{
+ return global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS) +
+ get_nr_dirty_inodes();
+}
+
+static long wb_check_background_flush(struct bdi_writeback *wb)
+{
+ if (over_bground_thresh()) {
+
+ struct wb_writeback_work work = {
+ .nr_pages = LONG_MAX,
+ .sync_mode = WB_SYNC_NONE,
+ .for_background = 1,
+ .range_cyclic = 1,
+ };
+
+ return wb_writeback(wb, &work);
+ }
+
+ return 0;
+}
+
static long wb_check_old_data_flush(struct bdi_writeback *wb)
{
unsigned long expired;
return 0;
wb->last_old_flush = jiffies;
- nr_pages = global_page_state(NR_FILE_DIRTY) +
- global_page_state(NR_UNSTABLE_NFS) +
- (inodes_stat.nr_inodes - inodes_stat.nr_unused);
+ nr_pages = get_nr_dirty_pages();
if (nr_pages) {
struct wb_writeback_work work = {
struct wb_writeback_work *work;
long wrote = 0;
+ set_bit(BDI_writeback_running, &wb->bdi->state);
while ((work = get_next_work_item(bdi)) != NULL) {
/*
* Override sync mode, in case we must wait for completion
* Check for periodic writeback, kupdated() style
*/
wrote += wb_check_old_data_flush(wb);
+ wrote += wb_check_background_flush(wb);
+ clear_bit(BDI_writeback_running, &wb->bdi->state);
return wrote;
}
{
struct bdi_writeback *wb = data;
struct backing_dev_info *bdi = wb->bdi;
- unsigned long last_active = jiffies;
- unsigned long wait_jiffies = -1UL;
long pages_written;
- /*
- * Add us to the active bdi_list
- */
- spin_lock_bh(&bdi_lock);
- list_add_rcu(&bdi->bdi_list, &bdi_list);
- spin_unlock_bh(&bdi_lock);
-
- current->flags |= PF_FLUSHER | PF_SWAPWRITE;
+ current->flags |= PF_SWAPWRITE;
set_freezable();
+ wb->last_active = jiffies;
/*
* Our parent may run at a different priority, just set us to normal
*/
set_user_nice(current, 0);
- /*
- * Clear pending bit and wakeup anybody waiting to tear us down
- */
- clear_bit(BDI_pending, &bdi->state);
- smp_mb__after_clear_bit();
- wake_up_bit(&bdi->state, BDI_pending);
-
trace_writeback_thread_start(bdi);
while (!kthread_should_stop()) {
+ /*
+ * Remove own delayed wake-up timer, since we are already awake
+ * and we'll take care of the preriodic write-back.
+ */
+ del_timer(&wb->wakeup_timer);
+
pages_written = wb_do_writeback(wb, 0);
trace_writeback_pages_written(pages_written);
if (pages_written)
- last_active = jiffies;
- else if (wait_jiffies != -1UL) {
- unsigned long max_idle;
+ wb->last_active = jiffies;
- /*
- * Longest period of inactivity that we tolerate. If we
- * see dirty data again later, the task will get
- * recreated automatically.
- */
- max_idle = max(5UL * 60 * HZ, wait_jiffies);
- if (time_after(jiffies, max_idle + last_active))
- break;
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!list_empty(&bdi->work_list) || kthread_should_stop()) {
+ __set_current_state(TASK_RUNNING);
+ continue;
}
- if (dirty_writeback_interval) {
- wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10);
- schedule_timeout_interruptible(wait_jiffies);
- } else {
- set_current_state(TASK_INTERRUPTIBLE);
- if (list_empty_careful(&wb->bdi->work_list) &&
- !kthread_should_stop())
- schedule();
- __set_current_state(TASK_RUNNING);
+ if (wb_has_dirty_io(wb) && dirty_writeback_interval)
+ schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
+ else {
+ /*
+ * We have nothing to do, so can go sleep without any
+ * timeout and save power. When a work is queued or
+ * something is made dirty - we will be woken up.
+ */
+ schedule();
}
try_to_freeze();
}
- wb->task = NULL;
-
- /*
- * Flush any work that raced with us exiting. No new work
- * will be added, since this bdi isn't discoverable anymore.
- */
+ /* Flush any work that raced with us exiting */
if (!list_empty(&bdi->work_list))
wb_do_writeback(wb, 1);
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
if (!bdi_has_dirty_io(bdi))
continue;
- __bdi_start_writeback(bdi, nr_pages, false, false);
+ __bdi_start_writeback(bdi, nr_pages, false);
}
rcu_read_unlock();
}
* In short, make sure you hash any inodes _before_ you start marking
* them dirty.
*
- * This function *must* be atomic for the I_DIRTY_PAGES case -
- * set_page_dirty() is called under spinlock in several places.
- *
* Note that for blockdevs, inode->dirtied_when represents the dirtying time of
* the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of
* the kernel-internal blockdev inode represents the dirtying time of the
void __mark_inode_dirty(struct inode *inode, int flags)
{
struct super_block *sb = inode->i_sb;
+ struct backing_dev_info *bdi = NULL;
/*
* Don't do this for I_DIRTY_PAGES - that doesn't actually
*/
if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
if (sb->s_op->dirty_inode)
- sb->s_op->dirty_inode(inode);
+ sb->s_op->dirty_inode(inode, flags);
}
/*
if (unlikely(block_dump))
block_dump___mark_inode_dirty(inode);
- spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY;
* superblock list, based upon its state.
*/
if (inode->i_state & I_SYNC)
- goto out;
+ goto out_unlock_inode;
/*
* Only add valid (hashed) inodes to the superblock's
* dirty list. Add blockdev inodes as well.
*/
if (!S_ISBLK(inode->i_mode)) {
- if (hlist_unhashed(&inode->i_hash))
- goto out;
+ if (inode_unhashed(inode))
+ goto out_unlock_inode;
}
- if (inode->i_state & (I_FREEING|I_CLEAR))
- goto out;
+ if (inode->i_state & I_FREEING)
+ goto out_unlock_inode;
/*
* If the inode was already on b_dirty/b_io/b_more_io, don't
* reposition it (that would break b_dirty time-ordering).
*/
if (!was_dirty) {
- struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
- struct backing_dev_info *bdi = wb->bdi;
-
- if (bdi_cap_writeback_dirty(bdi) &&
- !test_bit(BDI_registered, &bdi->state)) {
- WARN_ON(1);
- printk(KERN_ERR "bdi-%s not registered\n",
- bdi->name);
+ bool wakeup_bdi = false;
+ bdi = inode_to_bdi(inode);
+
+ if (bdi_cap_writeback_dirty(bdi)) {
+ WARN(!test_bit(BDI_registered, &bdi->state),
+ "bdi-%s not registered\n", bdi->name);
+
+ /*
+ * If this is the first dirty inode for this
+ * bdi, we have to wake-up the corresponding
+ * bdi thread to make sure background
+ * write-back happens later.
+ */
+ if (!wb_has_dirty_io(&bdi->wb))
+ wakeup_bdi = true;
}
+ spin_unlock(&inode->i_lock);
+ spin_lock(&inode_wb_list_lock);
inode->dirtied_when = jiffies;
- list_move(&inode->i_list, &wb->b_dirty);
+ list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
+ spin_unlock(&inode_wb_list_lock);
+
+ if (wakeup_bdi)
+ bdi_wakeup_thread_delayed(bdi);
+ return;
}
}
-out:
- spin_unlock(&inode_lock);
+out_unlock_inode:
+ spin_unlock(&inode->i_lock);
+
}
EXPORT_SYMBOL(__mark_inode_dirty);
*/
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- spin_lock(&inode_lock);
+ spin_lock(&inode_sb_list_lock);
/*
* Data integrity sync. Must wait for all pages under writeback,
* we still have to wait for that writeout.
*/
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- struct address_space *mapping;
+ struct address_space *mapping = inode->i_mapping;
- if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
- continue;
- mapping = inode->i_mapping;
- if (mapping->nrpages == 0)
+ spin_lock(&inode->i_lock);
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ (mapping->nrpages == 0)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
__iget(inode);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_sb_list_lock);
+
/*
- * We hold a reference to 'inode' so it couldn't have
- * been removed from s_inodes list while we dropped the
- * inode_lock. We cannot iput the inode now as we can
- * be holding the last reference and we cannot iput it
- * under inode_lock. So we keep the reference and iput
- * it later.
+ * We hold a reference to 'inode' so it couldn't have been
+ * removed from s_inodes list while we dropped the
+ * inode_sb_list_lock. We cannot iput the inode now as we can
+ * be holding the last reference and we cannot iput it under
+ * inode_sb_list_lock. So we keep the reference and iput it
+ * later.
*/
iput(old_inode);
old_inode = inode;
cond_resched();
- spin_lock(&inode_lock);
+ spin_lock(&inode_sb_list_lock);
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_sb_list_lock);
iput(old_inode);
}
/**
- * writeback_inodes_sb - writeback dirty inodes from given super_block
+ * writeback_inodes_sb_nr - writeback dirty inodes from given super_block
* @sb: the superblock
+ * @nr: the number of pages to write
*
* Start writeback on some inodes on this super_block. No guarantees are made
* on how many (if any) will be written, and this function does not wait
- * for IO completion of submitted IO. The number of pages submitted is
- * returned.
+ * for IO completion of submitted IO.
*/
-void writeback_inodes_sb(struct super_block *sb)
+void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)
{
- unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
- unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
DECLARE_COMPLETION_ONSTACK(done);
struct wb_writeback_work work = {
- .sb = sb,
- .sync_mode = WB_SYNC_NONE,
- .done = &done,
+ .sb = sb,
+ .sync_mode = WB_SYNC_NONE,
+ .tagged_writepages = 1,
+ .done = &done,
+ .nr_pages = nr,
};
WARN_ON(!rwsem_is_locked(&sb->s_umount));
-
- work.nr_pages = nr_dirty + nr_unstable +
- (inodes_stat.nr_inodes - inodes_stat.nr_unused);
-
bdi_queue_work(sb->s_bdi, &work);
wait_for_completion(&done);
}
+EXPORT_SYMBOL(writeback_inodes_sb_nr);
+
+/**
+ * writeback_inodes_sb - writeback dirty inodes from given super_block
+ * @sb: the superblock
+ *
+ * Start writeback on some inodes on this super_block. No guarantees are made
+ * on how many (if any) will be written, and this function does not wait
+ * for IO completion of submitted IO.
+ */
+void writeback_inodes_sb(struct super_block *sb)
+{
+ return writeback_inodes_sb_nr(sb, get_nr_dirty_pages());
+}
EXPORT_SYMBOL(writeback_inodes_sb);
/**
}
EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
+/**
+ * writeback_inodes_sb_if_idle - start writeback if none underway
+ * @sb: the superblock
+ * @nr: the number of pages to write
+ *
+ * Invoke writeback_inodes_sb if no writeback is currently underway.
+ * Returns 1 if writeback was started, 0 if not.
+ */
+int writeback_inodes_sb_nr_if_idle(struct super_block *sb,
+ unsigned long nr)
+{
+ if (!writeback_in_progress(sb->s_bdi)) {
+ down_read(&sb->s_umount);
+ writeback_inodes_sb_nr(sb, nr);
+ up_read(&sb->s_umount);
+ return 1;
+ } else
+ return 0;
+}
+EXPORT_SYMBOL(writeback_inodes_sb_nr_if_idle);
+
/**
* sync_inodes_sb - sync sb inode pages
* @sb: the superblock
*
* This function writes and waits on any dirty inode belonging to this
- * super_block. The number of pages synced is returned.
+ * super_block.
*/
void sync_inodes_sb(struct super_block *sb)
{
wbc.nr_to_write = 0;
might_sleep();
- spin_lock(&inode_lock);
+ spin_lock(&inode_wb_list_lock);
+ spin_lock(&inode->i_lock);
ret = writeback_single_inode(inode, &wbc);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_wb_list_lock);
if (sync)
inode_sync_wait(inode);
return ret;
{
int ret;
- spin_lock(&inode_lock);
+ spin_lock(&inode_wb_list_lock);
+ spin_lock(&inode->i_lock);
ret = writeback_single_inode(inode, wbc);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_wb_list_lock);
return ret;
}
EXPORT_SYMBOL(sync_inode);
+
+/**
+ * sync_inode_metadata - write an inode to disk
+ * @inode: the inode to sync
+ * @wait: wait for I/O to complete.
+ *
+ * Write an inode to disk and adjust its dirty state after completion.
+ *
+ * Note: only writes the actual inode, no associated data or other metadata.
+ */
+int sync_inode_metadata(struct inode *inode, int wait)
+{
+ struct writeback_control wbc = {
+ .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE,
+ .nr_to_write = 0, /* metadata-only */
+ };
+
+ return sync_inode(inode, &wbc);
+}
+EXPORT_SYMBOL(sync_inode_metadata);
Code Review / linux-2.6.git / blobdiff