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| author | Jan Kara <jack@suse.cz> | 2014-04-03 14:46:23 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-26 17:19:05 -0700 |
| commit | 1c23ab6f8860f1d5823868d868314f674333a8b3 (patch) | |
| tree | 9953b1d22dc2fed150e59bc9a00fa8fa56017f62 /fs | |
| parent | 67001f3a0bc4373452a2a3241e4b038bdc796cda (diff) | |
| download | kernel-common-1c23ab6f8860f1d5823868d868314f674333a8b3.tar.gz kernel-common-1c23ab6f8860f1d5823868d868314f674333a8b3.tar.bz2 kernel-common-1c23ab6f8860f1d5823868d868314f674333a8b3.zip | |
bdi: avoid oops on device removal
commit 5acda9d12dcf1ad0d9a5a2a7c646de3472fa7555 upstream.
After commit 839a8e8660b6 ("writeback: replace custom worker pool
implementation with unbound workqueue") when device is removed while we
are writing to it we crash in bdi_writeback_workfn() ->
set_worker_desc() because bdi->dev is NULL.
This can happen because even though bdi_unregister() cancels all pending
flushing work, nothing really prevents new ones from being queued from
balance_dirty_pages() or other places.
Fix the problem by clearing BDI_registered bit in bdi_unregister() and
checking it before scheduling of any flushing work.
Fixes: 839a8e8660b6777e7fe4e80af1a048aebe2b5977
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Derek Basehore <dbasehore@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fs-writeback.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 6788fe0c9761..a16315957ef3 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -89,16 +89,29 @@ static inline struct inode *wb_inode(struct list_head *head) #define CREATE_TRACE_POINTS #include <trace/events/writeback.h> +static void bdi_wakeup_thread(struct backing_dev_info *bdi) +{ + spin_lock_bh(&bdi->wb_lock); + if (test_bit(BDI_registered, &bdi->state)) + mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); + spin_unlock_bh(&bdi->wb_lock); +} + static void bdi_queue_work(struct backing_dev_info *bdi, struct wb_writeback_work *work) { trace_writeback_queue(bdi, work); spin_lock_bh(&bdi->wb_lock); + if (!test_bit(BDI_registered, &bdi->state)) { + if (work->done) + complete(work->done); + goto out_unlock; + } list_add_tail(&work->list, &bdi->work_list); - spin_unlock_bh(&bdi->wb_lock); - mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); +out_unlock: + spin_unlock_bh(&bdi->wb_lock); } static void @@ -114,7 +127,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, work = kzalloc(sizeof(*work), GFP_ATOMIC); if (!work) { trace_writeback_nowork(bdi); - mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); + bdi_wakeup_thread(bdi); return; } @@ -161,7 +174,7 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi) * writeback as soon as there is no other work to do. */ trace_writeback_wake_background(bdi); - mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); + bdi_wakeup_thread(bdi); } /* @@ -1017,7 +1030,7 @@ void bdi_writeback_workfn(struct work_struct *work) current->flags |= PF_SWAPWRITE; if (likely(!current_is_workqueue_rescuer() || - list_empty(&bdi->bdi_list))) { + !test_bit(BDI_registered, &bdi->state))) { /* * The normal path. Keep writing back @bdi until its * work_list is empty. Note that this path is also taken |