[dm-devel] dm: lock bd_mutex when setting device size
Mike Snitzer
snitzer at redhat.com
Fri Oct 29 21:50:01 UTC 2010
Avoid taking md->bdev->bd_inode->i_mutex to update the DM block device's
size. Using md->bdev->bd_mutex eliminates the potential for deadlock if
an fsync is racing with a device resize.
revalidate_disk() was avoided because it would flush_disk() while the DM
device is suspended.
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
Cc: Jun'ichi Nomura <j-nomura at ce.jp.nec.com>
---
drivers/md/dm.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
Jun'ichi, was the following your implict Acked-by? Care to make it
explicit?
"Anyway, I think your bd_mutex patch should be fine for now and is
better than the current code with i_mutex, which has a real deadlock
issue."
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7cb1352..248794a 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1996,9 +1996,9 @@ static void __set_size(struct mapped_device *md, sector_t size)
{
set_capacity(md->disk, size);
- mutex_lock(&md->bdev->bd_inode->i_mutex);
+ mutex_lock(&md->bdev->bd_mutex);
i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
- mutex_unlock(&md->bdev->bd_inode->i_mutex);
+ mutex_unlock(&md->bdev->bd_mutex);
}
/*
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