talos-obmc-linux/mm/backing-dev.c, branch v2.6.33-rc5

flusher: Fix PF_FROZEN race

2009-12-03T12:49:43+00:00

To touch task->flags directly is racy. thaw_process() still has race (changing non_current->flags, but this is another issue) though, I think it's much better off. So, use thaw_process() instead. Signed-off-by: OGAWA Hirofumi Signed-off-by: Jens Axboe

Thaw refrigerated bdi flusher threads before invoking kthread_stop on them

2009-11-12T12:08:11+00:00

Unfreezes the bdi flusher task when the said task needs to exit. Steps to reproduce this. 1) Mount a file system from MMC/SD card. 2) Unmount the file system. This creates a flusher task. 3) Attempt suspend to RAM. System is unresponsive. This is because the bdi flusher thread is already in the refrigerator and will remain so until it is thawed. The MMC driver suspend routine call stack will ultimately issue a 'kthread_stop' on the bdi flusher thread and will block until the flusher thread is exited. Since the bdi flusher thread is in the refrigerator it never cleans up until thawed. Signed-off-by: Romit Dasgupta Signed-off-by: Jens Axboe

backing-dev: bdi sb prune should be in the unregister path, not destroy

2009-11-03T19:18:44+00:00

Commit 592b09a42fc3ae6737a0f3ecf4fee42ecd0296f8 was different from the tested path, in that it moved the bdi super_block prune from unregister to destroy context. This doesn't fully fix the sync hang bug on unexpected device removal, as need to prune the bdi cache pointer before killing flusher thread. Tested-by: Artur Skawina Signed-off-by: Jens Axboe

backing-dev: ensure that a removed bdi no longer has super_block referencing it

2009-10-29T10:46:12+00:00

When the bdi is being removed, we have to ensure that no super_blocks currently have that cached in sb->s_bdi. Normally this is ensured by the sb having a longer life span than the bdi, but if the device is suddenly yanked, we have to kill this reference. sb->s_bdi is pointed to freed memory at that point. This fixes a problem with sync(1) hanging when a USB stick is pulled without cleanly umounting it first. Reported-by: Pavel Machek Signed-off-by: Jens Axboe

writeback: kill space in debugfs item name

2009-10-09T11:01:27+00:00

The space is not script friendly, kill it. Signed-off-by: Wu Fengguang Signed-off-by: Jens Axboe

writeback: splice dirty inode entries to default bdi on bdi_destroy()

2009-09-16T13:18:52+00:00

We cannot safely ensure that the inodes are all gone at this point in time, and we must not destroy this bdi with inodes having off it. So just splice our entries to the default bdi since that one will always persist. Signed-off-by: Jens Axboe

writeback: use RCU to protect bdi_list

2009-09-16T13:18:51+00:00

Now that bdi_writeback_all() no longer handles integrity writeback, it doesn't have to block anymore. This means that we can switch bdi_list reader side protection to RCU. Signed-off-by: Jens Axboe

writeback: check for registered bdi in flusher add and inode dirty

2009-09-11T07:20:26+00:00

Also a debugging aid. We want to catch dirty inodes being added to backing devices that don't do writeback. Signed-off-by: Jens Axboe

writeback: add name to backing_dev_info

2009-09-11T07:20:26+00:00

This enables us to track who does what and print info. Its main use is catching dirty inodes on the default_backing_dev_info, so we can fix that up. Signed-off-by: Jens Axboe

writeback: add some debug inode list counters to bdi stats

2009-09-11T07:20:26+00:00

Add some debug entries to be able to inspect the internal state of the writeback details. Signed-off-by: Jens Axboe