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Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block

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* 'writeback' of git://git.kernel.dk/linux-2.6-block:
  writeback: fix possible bdi writeback refcounting problem
  writeback: Fix bdi use after free in wb_work_complete()
  writeback: improve scalability of bdi writeback work queues
  writeback: remove smp_mb(), it's not needed with list_add_tail_rcu()
  writeback: use schedule_timeout_interruptible()
  writeback: add comments to bdi_work structure
  writeback: splice dirty inode entries to default bdi on bdi_destroy()
  writeback: separate starting of sync vs opportunistic writeback
  writeback: inline allocation failure handling in bdi_alloc_queue_work()
  writeback: use RCU to protect bdi_list
  writeback: only use bdi_writeback_all() for WB_SYNC_NONE writeout
  fs: Assign bdi in super_block
  writeback: make wb_writeback() take an argument structure
  writeback: merely wakeup flusher thread if work allocation fails for WB_SYNC_NONE
  writeback: get rid of wbc->for_writepages
  fs: remove bdev->bd_inode_backing_dev_info
This commit is contained in:
Linus Torvalds 2009-09-16 07:45:38 -07:00
commit a3eb51ecfa
21 changed files with 264 additions and 263 deletions
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1
fs/afs/write.c
View File

@ -712,7 +712,6 @@ int afs_writeback_all(struct afs_vnode *vnode)
.bdi = mapping->backing_dev_info,
.sync_mode = WB_SYNC_ALL,
.nr_to_write = LONG_MAX,
.for_writepages = 1,
.range_cyclic = 1,
};
int ret;

1
fs/block_dev.c
View File

@ -420,7 +420,6 @@ static void bdev_destroy_inode(struct inode *inode)
{
struct bdev_inode *bdi = BDEV_I(inode);
bdi->bdev.bd_inode_backing_dev_info = NULL;
kmem_cache_free(bdev_cachep, bdi);
}

1
fs/btrfs/disk-io.c
View File

@ -1600,6 +1600,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
sb->s_blocksize = 4096;
sb->s_blocksize_bits = blksize_bits(4096);
sb->s_bdi = &fs_info->bdi;
/*
* we set the i_size on the btree inode to the max possible int.

1
fs/btrfs/ordered-data.c
View File

@ -740,7 +740,6 @@ int btrfs_fdatawrite_range(struct address_space *mapping, loff_t start,
.nr_to_write = mapping->nrpages * 2,
.range_start = start,
.range_end = end,
.for_writepages = 1,
};
return btrfs_writepages(mapping, &wbc);
}

345
fs/fs-writeback.c
View File

@ -34,22 +34,30 @@
*/
int nr_pdflush_threads;
/*
* Passed into wb_writeback(), essentially a subset of writeback_control
*/
struct wb_writeback_args {
long nr_pages;
struct super_block *sb;
enum writeback_sync_modes sync_mode;
int for_kupdate;
int range_cyclic;
};
/*
* Work items for the bdi_writeback threads
*/
struct bdi_work {
struct list_head list;
struct list_head wait_list;
struct rcu_head rcu_head;
struct list_head list; /* pending work list */
struct rcu_head rcu_head; /* for RCU free/clear of work */
unsigned long seen;
atomic_t pending;
unsigned long seen; /* threads that have seen this work */
atomic_t pending; /* number of threads still to do work */
struct super_block *sb;
unsigned long nr_pages;
enum writeback_sync_modes sync_mode;
struct wb_writeback_args args; /* writeback arguments */
unsigned long state;
unsigned long state; /* flag bits, see WS_* */
};
enum {
@ -66,22 +74,13 @@ static inline bool bdi_work_on_stack(struct bdi_work *work)
}
static inline void bdi_work_init(struct bdi_work *work,
struct writeback_control *wbc)
struct wb_writeback_args *args)
{
INIT_RCU_HEAD(&work->rcu_head);
work->sb = wbc->sb;
work->nr_pages = wbc->nr_to_write;
work->sync_mode = wbc->sync_mode;
work->args = *args;
work->state = WS_USED;
}
static inline void bdi_work_init_on_stack(struct bdi_work *work,
struct writeback_control *wbc)
{
bdi_work_init(work, wbc);
work->state |= WS_ONSTACK;
}
/**
* writeback_in_progress - determine whether there is writeback in progress
* @bdi: the device's backing_dev_info structure.
@ -98,6 +97,11 @@ static void bdi_work_clear(struct bdi_work *work)
{
clear_bit(WS_USED_B, &work->state);
smp_mb__after_clear_bit();
/*
* work can have disappeared at this point. bit waitq functions
* should be able to tolerate this, provided bdi_sched_wait does
* not dereference it's pointer argument.
*/
wake_up_bit(&work->state, WS_USED_B);
}
@ -113,7 +117,8 @@ static void bdi_work_free(struct rcu_head *head)
static void wb_work_complete(struct bdi_work *work)
{
const enum writeback_sync_modes sync_mode = work->sync_mode;
const enum writeback_sync_modes sync_mode = work->args.sync_mode;
int onstack = bdi_work_on_stack(work);
/*
* For allocated work, we can clear the done/seen bit right here.
@ -121,9 +126,9 @@ static void wb_work_complete(struct bdi_work *work)
* to after the RCU grace period, since the stack could be invalidated
* as soon as bdi_work_clear() has done the wakeup.
*/
if (!bdi_work_on_stack(work))
if (!onstack)
bdi_work_clear(work);
if (sync_mode == WB_SYNC_NONE || bdi_work_on_stack(work))
if (sync_mode == WB_SYNC_NONE || onstack)
call_rcu(&work->rcu_head, bdi_work_free);
}
@ -146,21 +151,19 @@ static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work)
static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work)
{
if (work) {
work->seen = bdi->wb_mask;
BUG_ON(!work->seen);
atomic_set(&work->pending, bdi->wb_cnt);
BUG_ON(!bdi->wb_cnt);
work->seen = bdi->wb_mask;
BUG_ON(!work->seen);
atomic_set(&work->pending, bdi->wb_cnt);
BUG_ON(!bdi->wb_cnt);
/*
* Make sure stores are seen before it appears on the list
*/
smp_mb();
spin_lock(&bdi->wb_lock);
list_add_tail_rcu(&work->list, &bdi->work_list);
spin_unlock(&bdi->wb_lock);
}
/*
* list_add_tail_rcu() contains the necessary barriers to
* make sure the above stores are seen before the item is
* noticed on the list
*/
spin_lock(&bdi->wb_lock);
list_add_tail_rcu(&work->list, &bdi->work_list);
spin_unlock(&bdi->wb_lock);
/*
* If the default thread isn't there, make sure we add it. When
@ -171,15 +174,7 @@ static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work)
else {
struct bdi_writeback *wb = &bdi->wb;
/*
* If we failed allocating the bdi work item, wake up the wb
* thread always. As a safety precaution, it'll flush out
* everything
*/
if (!wb_has_dirty_io(wb)) {
if (work)
wb_clear_pending(wb, work);
} else if (wb->task)
if (wb->task)
wake_up_process(wb->task);
}
}
@ -194,48 +189,75 @@ 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 wb_writeback_args *args)
{
struct bdi_work *work;
/*
* This is WB_SYNC_NONE writeback, so if allocation fails just
* wakeup the thread for old dirty data writeback
*/
work = kmalloc(sizeof(*work), GFP_ATOMIC);
if (work)
bdi_work_init(work, wbc);
if (work) {
bdi_work_init(work, args);
bdi_queue_work(bdi, work);
} else {
struct bdi_writeback *wb = &bdi->wb;
return work;
if (wb->task)
wake_up_process(wb->task);
}
}
void bdi_start_writeback(struct writeback_control *wbc)
/**
* bdi_sync_writeback - start and wait for writeback
* @bdi: the backing device to write from
* @sb: write inodes from this super_block
*
* Description:
* This does WB_SYNC_ALL data integrity writeback and waits for the
* IO to complete. Callers must hold the sb s_umount semaphore for
* reading, to avoid having the super disappear before we are done.
*/
static void bdi_sync_writeback(struct backing_dev_info *bdi,
struct super_block *sb)
{
const bool must_wait = wbc->sync_mode == WB_SYNC_ALL;
struct bdi_work work_stack, *work = NULL;
struct wb_writeback_args args = {
.sb = sb,
.sync_mode = WB_SYNC_ALL,
.nr_pages = LONG_MAX,
.range_cyclic = 0,
};
struct bdi_work work;
if (!must_wait)
work = bdi_alloc_work(wbc);
bdi_work_init(&work, &args);
work.state |= WS_ONSTACK;
if (!work) {
work = &work_stack;
bdi_work_init_on_stack(work, wbc);
}
bdi_queue_work(bdi, &work);
bdi_wait_on_work_clear(&work);
}
bdi_queue_work(wbc->bdi, work);
/**
* bdi_start_writeback - start writeback
* @bdi: the backing device to write from
* @nr_pages: the number of pages to write
*
* Description:
* This does WB_SYNC_NONE opportunistic writeback. The IO is only
* started when this function returns, we make no guarentees on
* completion. Caller need not hold sb s_umount semaphore.
*
*/
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
{
struct wb_writeback_args args = {
.sync_mode = WB_SYNC_NONE,
.nr_pages = nr_pages,
.range_cyclic = 1,
};
/*
* If the sync mode is WB_SYNC_ALL, block waiting for the work to
* complete. If not, we only need to wait for the work to be started,
* if we allocated it on-stack. We use the same mechanism, if the
* wait bit is set in the bdi_work struct, then threads will not
* clear pending until after they are done.
*
* Note that work == &work_stack if must_wait is true, so we don't
* need to do call_rcu() here ever, since the completion path will
* have done that for us.
*/
if (must_wait || work == &work_stack) {
bdi_wait_on_work_clear(work);
if (work != &work_stack)
call_rcu(&work->rcu_head, bdi_work_free);
}
bdi_alloc_queue_work(bdi, &args);
}
/*
@ -671,17 +693,16 @@ static inline bool over_bground_thresh(void)
* older_than_this takes precedence over nr_to_write. So we'll only write back
* all dirty pages if they are all attached to "old" mappings.
*/
static long wb_writeback(struct bdi_writeback *wb, long nr_pages,
struct super_block *sb,
enum writeback_sync_modes sync_mode, int for_kupdate)
static long wb_writeback(struct bdi_writeback *wb,
struct wb_writeback_args *args)
{
struct writeback_control wbc = {
.bdi = wb->bdi,
.sb = sb,
.sync_mode = sync_mode,
.sb = args->sb,
.sync_mode = args->sync_mode,
.older_than_this = NULL,
.for_kupdate = for_kupdate,
.range_cyclic = 1,
.for_kupdate = args->for_kupdate,
.range_cyclic = args->range_cyclic,
};
unsigned long oldest_jif;
long wrote = 0;
@ -691,13 +712,18 @@ static long wb_writeback(struct bdi_writeback *wb, long nr_pages,
oldest_jif = jiffies -
msecs_to_jiffies(dirty_expire_interval * 10);
}
if (!wbc.range_cyclic) {
wbc.range_start = 0;
wbc.range_end = LLONG_MAX;
}
for (;;) {
/*
* Don't flush anything for non-integrity writeback where
* no nr_pages was given
*/
if (!for_kupdate && nr_pages <= 0 && sync_mode == WB_SYNC_NONE)
if (!args->for_kupdate && args->nr_pages <= 0 &&
args->sync_mode == WB_SYNC_NONE)
break;
/*
@ -705,7 +731,8 @@ static long wb_writeback(struct bdi_writeback *wb, long nr_pages,
* periodic background writeout and we are below the
* background dirty threshold, don't do anything
*/
if (for_kupdate && nr_pages <= 0 && !over_bground_thresh())
if (args->for_kupdate && args->nr_pages <= 0 &&
!over_bground_thresh())
break;
wbc.more_io = 0;
@ -713,7 +740,7 @@ static long wb_writeback(struct bdi_writeback *wb, long nr_pages,
wbc.nr_to_write = MAX_WRITEBACK_PAGES;
wbc.pages_skipped = 0;
writeback_inodes_wb(wb, &wbc);
nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;
/*
@ -731,7 +758,11 @@ static long wb_writeback(struct bdi_writeback *wb, long nr_pages,
/*
* Return the next bdi_work struct that hasn't been processed by this
* wb thread yet
* wb thread yet. ->seen is initially set for each thread that exists
* for this device, when a thread first notices a piece of work it
* clears its bit. Depending on writeback type, the thread will notify
* completion on either receiving the work (WB_SYNC_NONE) or after
* it is done (WB_SYNC_ALL).
*/
static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi,
struct bdi_writeback *wb)
@ -741,8 +772,9 @@ static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi,
rcu_read_lock();
list_for_each_entry_rcu(work, &bdi->work_list, list) {
if (!test_and_clear_bit(wb->nr, &work->seen))
if (!test_bit(wb->nr, &work->seen))
continue;
clear_bit(wb->nr, &work->seen);
ret = work;
break;
@ -767,8 +799,16 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
global_page_state(NR_UNSTABLE_NFS) +
(inodes_stat.nr_inodes - inodes_stat.nr_unused);
if (nr_pages)
return wb_writeback(wb, nr_pages, NULL, WB_SYNC_NONE, 1);
if (nr_pages) {
struct wb_writeback_args args = {
.nr_pages = nr_pages,
.sync_mode = WB_SYNC_NONE,
.for_kupdate = 1,
.range_cyclic = 1,
};
return wb_writeback(wb, &args);
}
return 0;
}
@ -780,35 +820,31 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
{
struct backing_dev_info *bdi = wb->bdi;
struct bdi_work *work;
long nr_pages, wrote = 0;
long wrote = 0;
while ((work = get_next_work_item(bdi, wb)) != NULL) {
enum writeback_sync_modes sync_mode;
nr_pages = work->nr_pages;
struct wb_writeback_args args = work->args;
/*
* Override sync mode, in case we must wait for completion
*/
if (force_wait)
work->sync_mode = sync_mode = WB_SYNC_ALL;
else
sync_mode = work->sync_mode;
work->args.sync_mode = args.sync_mode = WB_SYNC_ALL;
/*
* If this isn't a data integrity operation, just notify
* that we have seen this work and we are now starting it.
*/
if (sync_mode == WB_SYNC_NONE)
if (args.sync_mode == WB_SYNC_NONE)
wb_clear_pending(wb, work);
wrote += wb_writeback(wb, nr_pages, work->sb, sync_mode, 0);
wrote += wb_writeback(wb, &args);
/*
* This is a data integrity writeback, so only do the
* notification when we have completed the work.
*/
if (sync_mode == WB_SYNC_ALL)
if (args.sync_mode == WB_SYNC_ALL)
wb_clear_pending(wb, work);
}
@ -849,8 +885,7 @@ int bdi_writeback_task(struct bdi_writeback *wb)
}
wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10);
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(wait_jiffies);
schedule_timeout_interruptible(wait_jiffies);
try_to_freeze();
}
@ -858,67 +893,28 @@ 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. This does WB_SYNC_NONE
* writeback, for integrity writeback see bdi_sync_writeback().
*/
static void bdi_writeback_all(struct writeback_control *wbc)
static void bdi_writeback_all(struct super_block *sb, long nr_pages)
{
const bool must_wait = wbc->sync_mode == WB_SYNC_ALL;
struct wb_writeback_args args = {
.sb = sb,
.nr_pages = nr_pages,
.sync_mode = WB_SYNC_NONE,
};
struct backing_dev_info *bdi;
struct bdi_work *work;
LIST_HEAD(list);
restart:
spin_lock(&bdi_lock);
list_for_each_entry(bdi, &bdi_list, bdi_list) {
struct bdi_work *work;
rcu_read_lock();
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
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, &args);
}
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);
}
rcu_read_unlock();
}
/*
@ -927,17 +923,10 @@ restart:
*/
void wakeup_flusher_threads(long nr_pages)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE,
.older_than_this = NULL,
.range_cyclic = 1,
};
if (nr_pages == 0)
nr_pages = global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS);
wbc.nr_to_write = nr_pages;
bdi_writeback_all(&wbc);
bdi_writeback_all(NULL, nr_pages);
}
static noinline void block_dump___mark_inode_dirty(struct inode *inode)
@ -1084,7 +1073,7 @@ EXPORT_SYMBOL(__mark_inode_dirty);
* on the writer throttling path, and we get decent balancing between many
* throttled threads: we don't want them all piling up on inode_sync_wait.
*/
static void wait_sb_inodes(struct writeback_control *wbc)
static void wait_sb_inodes(struct super_block *sb)
{
struct inode *inode, *old_inode = NULL;
@ -1092,7 +1081,7 @@ static void wait_sb_inodes(struct writeback_control *wbc)
* We need to be protected against the filesystem going from
* r/o to r/w or vice versa.
*/
WARN_ON(!rwsem_is_locked(&wbc->sb->s_umount));
WARN_ON(!rwsem_is_locked(&sb->s_umount));
spin_lock(&inode_lock);
@ -1103,7 +1092,7 @@ static void wait_sb_inodes(struct writeback_control *wbc)
* In which case, the inode may not be on the dirty list, but
* we still have to wait for that writeout.
*/
list_for_each_entry(inode, &wbc->sb->s_inodes, i_sb_list) {
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
struct address_space *mapping;
if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
@ -1143,14 +1132,8 @@ static void wait_sb_inodes(struct writeback_control *wbc)
* for IO completion of submitted IO. The number of pages submitted is
* returned.
*/
long writeback_inodes_sb(struct super_block *sb)
void writeback_inodes_sb(struct super_block *sb)
{
struct writeback_control wbc = {
.sb = sb,
.sync_mode = WB_SYNC_NONE,
.range_start = 0,
.range_end = LLONG_MAX,
};
unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
long nr_to_write;
@ -1158,9 +1141,7 @@ long writeback_inodes_sb(struct super_block *sb)
nr_to_write = nr_dirty + nr_unstable +
(inodes_stat.nr_inodes - inodes_stat.nr_unused);
wbc.nr_to_write = nr_to_write;
bdi_writeback_all(&wbc);
return nr_to_write - wbc.nr_to_write;
bdi_writeback_all(sb, nr_to_write);
}
EXPORT_SYMBOL(writeback_inodes_sb);
@ -1171,20 +1152,10 @@ EXPORT_SYMBOL(writeback_inodes_sb);
* This function writes and waits on any dirty inode belonging to this
* super_block. The number of pages synced is returned.
*/
long sync_inodes_sb(struct super_block *sb)
void sync_inodes_sb(struct super_block *sb)
{
struct writeback_control wbc = {
.sb = sb,
.sync_mode = WB_SYNC_ALL,
.range_start = 0,
.range_end = LLONG_MAX,
};
long nr_to_write = LONG_MAX; /* doesn't actually matter */
wbc.nr_to_write = nr_to_write;
bdi_writeback_all(&wbc);
wait_sb_inodes(&wbc);
return nr_to_write - wbc.nr_to_write;
bdi_sync_writeback(sb->s_bdi, sb);
wait_sb_inodes(sb);
}
EXPORT_SYMBOL(sync_inodes_sb);

2
fs/fuse/inode.c
View File

@ -894,6 +894,8 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto err_put_conn;
sb->s_bdi = &fc->bdi;
/* Handle umasking inside the fuse code */
if (sb->s_flags & MS_POSIXACL)
fc->dont_mask = 1;

4
fs/inode.c
View File

@ -182,9 +182,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
if (sb->s_bdev) {
struct backing_dev_info *bdi;
bdi = sb->s_bdev->bd_inode_backing_dev_info;
if (!bdi)
bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
mapping->backing_dev_info = bdi;
}
inode->i_private = NULL;

1
fs/jbd2/commit.c
View File

@ -220,7 +220,6 @@ static int journal_submit_inode_data_buffers(struct address_space *mapping)
.nr_to_write = mapping->nrpages * 2,
.range_start = 0,
.range_end = i_size_read(mapping->host),
.for_writepages = 1,
};
ret = generic_writepages(mapping, &wbc);

2
fs/nfs/super.c
View File

@ -1918,6 +1918,8 @@ static inline void nfs_initialise_sb(struct super_block *sb)
if (server->flags & NFS_MOUNT_NOAC)
sb->s_flags |= MS_SYNCHRONOUS;
sb->s_bdi = &server->backing_dev_info;
nfs_super_set_maxbytes(sb, server->maxfilesize);
}

1
fs/nfs/write.c
View File

@ -1490,7 +1490,6 @@ static int nfs_write_mapping(struct address_space *mapping, int how)
.nr_to_write = LONG_MAX,
.range_start = 0,
.range_end = LLONG_MAX,
.for_writepages = 1,
};
return __nfs_write_mapping(mapping, &wbc, how);

4
fs/nilfs2/the_nilfs.c
View File

@ -591,9 +591,7 @@ int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
bdi = nilfs->ns_bdev->bd_inode_backing_dev_info;
if (!bdi)
bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
nilfs->ns_bdi = bdi ? : &default_backing_dev_info;
/* Finding last segment */

6
fs/super.c
View File

@ -707,6 +707,12 @@ static int set_bdev_super(struct super_block *s, void *data)
{
s->s_bdev = data;
s->s_dev = s->s_bdev->bd_dev;
/*
* We set the bdi here to the queue backing, file systems can
* overwrite this in ->fill_super()
*/
s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
return 0;
}

9
fs/sync.c
View File

@ -27,6 +27,13 @@
*/
static int __sync_filesystem(struct super_block *sb, int wait)
{
/*
* This should be safe, as we require bdi backing to actually
* write out data in the first place
*/
if (!sb->s_bdi)
return 0;
/* Avoid doing twice syncing and cache pruning for quota sync */
if (!wait) {
writeout_quota_sb(sb, -1);
@ -101,7 +108,7 @@ restart:
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
if (!(sb->s_flags & MS_RDONLY) && sb->s_root)
if (!(sb->s_flags & MS_RDONLY) && sb->s_root && sb->s_bdi)
__sync_filesystem(sb, wait);
up_read(&sb->s_umount);

20
fs/ubifs/budget.c
View File

@ -54,29 +54,15 @@
* @nr_to_write: how many dirty pages to write-back
*
* This function shrinks UBIFS liability by means of writing back some amount
* of dirty inodes and their pages. Returns the amount of pages which were
* written back. The returned value does not include dirty inodes which were
* synchronized.
* of dirty inodes and their pages.
*
* Note, this function synchronizes even VFS inodes which are locked
* (@i_mutex) by the caller of the budgeting function, because write-back does
* not touch @i_mutex.
*/
static int shrink_liability(struct ubifs_info *c, int nr_to_write)
static void shrink_liability(struct ubifs_info *c, int nr_to_write)
{
int nr_written;
nr_written = writeback_inodes_sb(c->vfs_sb);
if (!nr_written) {
/*
* Re-try again but wait on pages/inodes which are being
* written-back concurrently (e.g., by pdflush).
*/
nr_written = sync_inodes_sb(c->vfs_sb);
}
dbg_budg("%d pages were written back", nr_written);
return nr_written;
writeback_inodes_sb(c->vfs_sb);
}
/**

1
fs/ubifs/super.c
View File

@ -1980,6 +1980,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto out_bdi;
sb->s_bdi = &c->bdi;
sb->s_fs_info = c;
sb->s_magic = UBIFS_SUPER_MAGIC;
sb->s_blocksize = UBIFS_BLOCK_SIZE;

3
include/linux/backing-dev.h
View File

@ -59,6 +59,7 @@ struct bdi_writeback {
struct backing_dev_info {
struct list_head bdi_list;
struct rcu_head rcu_head;
unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
unsigned long state; /* Always use atomic bitops on this */
unsigned int capabilities; /* Device capabilities */
@ -100,7 +101,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
const char *fmt, ...);
int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
void bdi_unregister(struct backing_dev_info *bdi);
void bdi_start_writeback(struct writeback_control *wbc);
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
int bdi_writeback_task(struct bdi_writeback *wb);
int bdi_has_dirty_io(struct backing_dev_info *bdi);

2
include/linux/fs.h
View File

@ -655,7 +655,6 @@ struct block_device {
int bd_invalidated;
struct gendisk * bd_disk;
struct list_head bd_list;
struct backing_dev_info *bd_inode_backing_dev_info;
/*
* Private data. You must have bd_claim'ed the block_device
* to use this. NOTE: bd_claim allows an owner to claim
@ -1343,6 +1342,7 @@ struct super_block {
int s_nr_dentry_unused; /* # of dentry on lru */
struct block_device *s_bdev;
struct backing_dev_info *s_bdi;
struct mtd_info *s_mtd;
struct list_head s_instances;
struct quota_info s_dquot; /* Diskquota specific options */

5
include/linux/writeback.h
View File

@ -50,7 +50,6 @@ struct writeback_control {
unsigned encountered_congestion:1; /* An output: a queue is full */
unsigned for_kupdate:1; /* A kupdate writeback */
unsigned for_reclaim:1; /* Invoked from the page allocator */
unsigned for_writepages:1; /* This is a writepages() call */
unsigned range_cyclic:1; /* range_start is cyclic */
unsigned more_io:1; /* more io to be dispatched */
/*
@ -69,8 +68,8 @@ struct writeback_control {
*/
struct bdi_writeback;
int inode_wait(void *);
long writeback_inodes_sb(struct super_block *);
long sync_inodes_sb(struct super_block *);
void writeback_inodes_sb(struct super_block *);
void sync_inodes_sb(struct super_block *);
void writeback_inodes_wbc(struct writeback_control *wbc);
long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
void wakeup_flusher_threads(long nr_pages);

6
include/trace/events/ext4.h
View File

@ -227,7 +227,6 @@ TRACE_EVENT(ext4_da_writepages,
__field( char, nonblocking )
__field( char, for_kupdate )
__field( char, for_reclaim )
__field( char, for_writepages )
__field( char, range_cyclic )
),
@ -241,16 +240,15 @@ TRACE_EVENT(ext4_da_writepages,
__entry->nonblocking = wbc->nonblocking;
__entry->for_kupdate = wbc->for_kupdate;
__entry->for_reclaim = wbc->for_reclaim;
__entry->for_writepages = wbc->for_writepages;
__entry->range_cyclic = wbc->range_cyclic;
),
TP_printk("dev %s ino %lu nr_t_write %ld pages_skipped %ld range_start %llu range_end %llu nonblocking %d for_kupdate %d for_reclaim %d for_writepages %d range_cyclic %d",
TP_printk("dev %s ino %lu nr_t_write %ld pages_skipped %ld range_start %llu range_end %llu nonblocking %d for_kupdate %d for_reclaim %d range_cyclic %d",
jbd2_dev_to_name(__entry->dev), __entry->ino, __entry->nr_to_write,
__entry->pages_skipped, __entry->range_start,
__entry->range_end, __entry->nonblocking,
__entry->for_kupdate, __entry->for_reclaim,
__entry->for_writepages, __entry->range_cyclic)
__entry->range_cyclic)
);
TRACE_EVENT(ext4_da_writepages_result,

90
mm/backing-dev.c
View File

@ -26,6 +26,12 @@ struct backing_dev_info default_backing_dev_info = {
EXPORT_SYMBOL_GPL(default_backing_dev_info);
static struct class *bdi_class;
/*
* bdi_lock protects updates to bdi_list and bdi_pending_list, as well as
* reader side protection for bdi_pending_list. bdi_list has RCU reader side
* locking.
*/
DEFINE_SPINLOCK(bdi_lock);
LIST_HEAD(bdi_list);
LIST_HEAD(bdi_pending_list);
@ -284,9 +290,9 @@ static int bdi_start_fn(void *ptr)
/*
* Add us to the active bdi_list
*/
spin_lock(&bdi_lock);
list_add(&bdi->bdi_list, &bdi_list);
spin_unlock(&bdi_lock);
spin_lock_bh(&bdi_lock);
list_add_rcu(&bdi->bdi_list, &bdi_list);
spin_unlock_bh(&bdi_lock);
bdi_task_init(bdi, wb);
@ -389,7 +395,7 @@ static int bdi_forker_task(void *ptr)
if (wb_has_dirty_io(me) || !list_empty(&me->bdi->work_list))
wb_do_writeback(me, 0);
spin_lock(&bdi_lock);
spin_lock_bh(&bdi_lock);
/*
* Check if any existing bdi's have dirty data without
@ -410,7 +416,7 @@ static int bdi_forker_task(void *ptr)
if (list_empty(&bdi_pending_list)) {
unsigned long wait;
spin_unlock(&bdi_lock);
spin_unlock_bh(&bdi_lock);
wait = msecs_to_jiffies(dirty_writeback_interval * 10);
schedule_timeout(wait);
try_to_freeze();
@ -426,7 +432,7 @@ static int bdi_forker_task(void *ptr)
bdi = list_entry(bdi_pending_list.next, struct backing_dev_info,
bdi_list);
list_del_init(&bdi->bdi_list);
spin_unlock(&bdi_lock);
spin_unlock_bh(&bdi_lock);
wb = &bdi->wb;
wb->task = kthread_run(bdi_start_fn, wb, "flush-%s",
@ -445,9 +451,9 @@ static int bdi_forker_task(void *ptr)
* a chance to flush other bdi's to free
* memory.
*/
spin_lock(&bdi_lock);
spin_lock_bh(&bdi_lock);
list_add_tail(&bdi->bdi_list, &bdi_pending_list);
spin_unlock(&bdi_lock);
spin_unlock_bh(&bdi_lock);
bdi_flush_io(bdi);
}
@ -456,6 +462,24 @@ static int bdi_forker_task(void *ptr)
return 0;
}
static void bdi_add_to_pending(struct rcu_head *head)
{
struct backing_dev_info *bdi;
bdi = container_of(head, struct backing_dev_info, rcu_head);
INIT_LIST_HEAD(&bdi->bdi_list);
spin_lock(&bdi_lock);
list_add_tail(&bdi->bdi_list, &bdi_pending_list);
spin_unlock(&bdi_lock);
/*
* We are now on the pending list, wake up bdi_forker_task()
* to finish the job and add us back to the active bdi_list
*/
wake_up_process(default_backing_dev_info.wb.task);
}
/*
* Add the default flusher task that gets created for any bdi
* that has dirty data pending writeout
@ -478,16 +502,29 @@ void static bdi_add_default_flusher_task(struct backing_dev_info *bdi)
* waiting for previous additions to finish.
*/
if (!test_and_set_bit(BDI_pending, &bdi->state)) {
list_move_tail(&bdi->bdi_list, &bdi_pending_list);
list_del_rcu(&bdi->bdi_list);
/*
* We are now on the pending list, wake up bdi_forker_task()
* to finish the job and add us back to the active bdi_list
* We must wait for the current RCU period to end before
* moving to the pending list. So schedule that operation
* from an RCU callback.
*/
wake_up_process(default_backing_dev_info.wb.task);
call_rcu(&bdi->rcu_head, bdi_add_to_pending);
}
}
/*
* Remove bdi from bdi_list, and ensure that it is no longer visible
*/
static void bdi_remove_from_list(struct backing_dev_info *bdi)
{
spin_lock_bh(&bdi_lock);
list_del_rcu(&bdi->bdi_list);
spin_unlock_bh(&bdi_lock);
synchronize_rcu();
}
int bdi_register(struct backing_dev_info *bdi, struct device *parent,
const char *fmt, ...)
{
@ -506,9 +543,9 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
goto exit;
}
spin_lock(&bdi_lock);
list_add_tail(&bdi->bdi_list, &bdi_list);
spin_unlock(&bdi_lock);
spin_lock_bh(&bdi_lock);
list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
spin_unlock_bh(&bdi_lock);
bdi->dev = dev;
@ -526,9 +563,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
wb->task = NULL;
ret = -ENOMEM;
spin_lock(&bdi_lock);
list_del(&bdi->bdi_list);
spin_unlock(&bdi_lock);
bdi_remove_from_list(bdi);
goto exit;
}
}
@ -565,9 +600,7 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
/*
* Make sure nobody finds us on the bdi_list anymore
*/
spin_lock(&bdi_lock);
list_del(&bdi->bdi_list);
spin_unlock(&bdi_lock);
bdi_remove_from_list(bdi);
/*
* Finally, kill the kernel threads. We don't need to be RCU
@ -599,6 +632,7 @@ int bdi_init(struct backing_dev_info *bdi)
bdi->max_ratio = 100;
bdi->max_prop_frac = PROP_FRAC_BASE;
spin_lock_init(&bdi->wb_lock);
INIT_RCU_HEAD(&bdi->rcu_head);
INIT_LIST_HEAD(&bdi->bdi_list);
INIT_LIST_HEAD(&bdi->wb_list);
INIT_LIST_HEAD(&bdi->work_list);
@ -634,7 +668,19 @@ void bdi_destroy(struct backing_dev_info *bdi)
{
int i;
WARN_ON(bdi_has_dirty_io(bdi));
/*
* Splice our entries to the default_backing_dev_info, if this
* bdi disappears
*/
if (bdi_has_dirty_io(bdi)) {
struct bdi_writeback *dst = &default_backing_dev_info.wb;
spin_lock(&inode_lock);
list_splice(&bdi->wb.b_dirty, &dst->b_dirty);
list_splice(&bdi->wb.b_io, &dst->b_io);
list_splice(&bdi->wb.b_more_io, &dst->b_more_io);
spin_unlock(&inode_lock);
}
bdi_unregister(bdi);

22
mm/page-writeback.c
View File

@ -315,7 +315,7 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio)
{
int ret = 0;
spin_lock(&bdi_lock);
spin_lock_bh(&bdi_lock);
if (min_ratio > bdi->max_ratio) {
ret = -EINVAL;
} else {
@ -327,7 +327,7 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio)
ret = -EINVAL;
}
}
spin_unlock(&bdi_lock);
spin_unlock_bh(&bdi_lock);
return ret;
}
@ -339,14 +339,14 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio)
if (max_ratio > 100)
return -EINVAL;
spin_lock(&bdi_lock);
spin_lock_bh(&bdi_lock);
if (bdi->min_ratio > max_ratio) {
ret = -EINVAL;
} else {
bdi->max_ratio = max_ratio;
bdi->max_prop_frac = (PROP_FRAC_BASE * max_ratio) / 100;
}
spin_unlock(&bdi_lock);
spin_unlock_bh(&bdi_lock);
return ret;
}
@ -582,16 +582,8 @@ static void balance_dirty_pages(struct address_space *mapping)
if ((laptop_mode && pages_written) ||
(!laptop_mode && ((nr_writeback = global_page_state(NR_FILE_DIRTY)
+ global_page_state(NR_UNSTABLE_NFS))
> background_thresh))) {
struct writeback_control wbc = {
.bdi = bdi,
.sync_mode = WB_SYNC_NONE,
.nr_to_write = nr_writeback,
};
bdi_start_writeback(&wbc);
}
> background_thresh)))
bdi_start_writeback(bdi, nr_writeback);
}
void set_page_dirty_balance(struct page *page, int page_mkwrite)
@ -1020,12 +1012,10 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
if (wbc->nr_to_write <= 0)
return 0;
wbc->for_writepages = 1;
if (mapping->a_ops->writepages)
ret = mapping->a_ops->writepages(mapping, wbc);
else
ret = generic_writepages(mapping, wbc);
wbc->for_writepages = 0;
return ret;
}