linux-stable.git/mm/backing-dev.c, branch linux-2.6.35.y

mm/backing-dev.c: reset bdi min_ratio in bdi_unregister()

2011-08-01T20:55:00+00:00

[ upstream commit ccb6108f5b0b541d3eb332c3a73e645c0f84278e ]

Vito said:

: The system has many usb disks coming and going day to day, with their
: respective bdi's having min_ratio set to 1 when inserted.  It works for
: some time until eventually min_ratio can no longer be set, even when the
: active set of bdi's seen in /sys/class/bdi/*/min_ratio doesn't add up to
: anywhere near 100.
:
: This then leads to an unrelated starvation problem caused by write-heavy
: fuse mounts being used atop the usb disks, a problem the min_ratio setting
: at the underlying devices bdi effectively prevents.

Fix this leakage by resetting the bdi min_ratio when unregistering the
BDI.

Signed-off-by: Peter Zijlstra 
Reported-by: Vito Caputo 
Cc: Wu Fengguang 
Cc: Miklos Szeredi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Andi Kleen

bdi: Initialize noop_backing_dev_info properly

2010-09-27T00:18:24+00:00

commit 976e48f8a5b02fc33f3e5cad87fb3fcea041a49c upstream.

Properly initialize this backing dev info so that writeback code does not
barf when getting to it e.g. via sb->s_bdi.

Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

writeback: simplify the write back thread queue

2010-07-06T06:59:53+00:00

First remove items from work_list as soon as we start working on them.  This
means we don't have to track any pending or visited state and can get
rid of all the RCU magic freeing the work items - we can simply free
them once the operation has finished.  Second use a real completion for
tracking synchronous requests - if the caller sets the completion pointer
we complete it, otherwise use it as a boolean indicator that we can free
the work item directly.  Third unify struct wb_writeback_args and struct
bdi_work into a single data structure, wb_writeback_work.  Previous we
set all parameters into a struct wb_writeback_args, copied it into
struct bdi_work, copied it again on the stack to use it there.  Instead
of just allocate one structure dynamically or on the stack and use it
all the way through the stack.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

writeback: remove writeback_inodes_wbc

2010-07-06T06:54:03+00:00

This was just an odd wrapper around writeback_inodes_wb.  Removing this
also allows to get rid of the bdi member of struct writeback_control
which was rather out of place there.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

writeback: fixups for !dirty_writeback_centisecs

2010-05-21T18:00:35+00:00

Commit 69b62d01 fixed up most of the places where we would enter
busy schedule() spins when disabling the periodic background
writeback. This fixes up the sb timer so that it doesn't get
hammered on with the delay disabled, and ensures that it gets
rearmed if needed when /proc/sys/vm/dirty_writeback_centisecs
gets modified.

bdi_forker_task() also needs to check for !dirty_writeback_centisecs
and use schedule() appropriately, fix that up too.

Signed-off-by: Jens Axboe

Catch filesystems lacking s_bdi

2010-04-25T06:54:42+00:00

noop_backing_dev_info is used only as a flag to mark filesystems that
don't have any backing store, like tmpfs, procfs, spufs, etc.

Signed-off-by: Joern Engel 

Changed the BUG_ON() to a WARN_ON(). Note that adding dirty inodes
to the noop_backing_dev_info is not legal and will not result in
them being flushed, but we already catch this condition in
__mark_inode_dirty() when checking for a registered bdi.

Signed-off-by: Jens Axboe

bdi: add helper function for doing init and register of a bdi for a file system

2010-04-22T09:39:36+00:00

Pretty trivial helper, just sets up the bdi and registers it. An atomic
sequence count is used to ensure that the registered sysfs names are
unique.

Signed-off-by: Jens Axboe

backing-dev: Handle class_create() failure

2010-04-02T07:46:55+00:00

I hit this when we had a bug in IDR for a few days. Basically sysfs would
fail to create new inodes since it uses an IDR and therefore class_create would
fail.

While we are unlikely to see this fail we may as well handle it instead of
oopsing.

Signed-off-by: Anton Blanchard 
Signed-off-by: Jens Axboe

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