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authorJan Kara <jack@suse.cz>2017-03-23 03:37:00 +0300
committerJens Axboe <axboe@fb.com>2017-03-23 05:11:33 +0300
commitf759741d9d913eb57784a94b9bca78b376fc26a9 (patch)
tree19832434e2c4c1db34bceee048f422b910300686 /include/linux/writeback.h
parentb1c51afc00f164457e126dcfc946fdd563948d26 (diff)
downloadlinux-f759741d9d913eb57784a94b9bca78b376fc26a9.tar.xz
block: Fix oops in locked_inode_to_wb_and_lock_list()
When block device is closed, we call inode_detach_wb() in __blkdev_put() which sets inode->i_wb to NULL. That is contrary to expectations that inode->i_wb stays valid once set during the whole inode's lifetime and leads to oops in wb_get() in locked_inode_to_wb_and_lock_list() because inode_to_wb() returned NULL. The reason why we called inode_detach_wb() is not valid anymore though. BDI is guaranteed to stay along until we call bdi_put() from bdev_evict_inode() so we can postpone calling inode_detach_wb() to that moment. Also add a warning to catch if someone uses inode_detach_wb() in a dangerous way. Reported-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include/linux/writeback.h')
-rw-r--r--include/linux/writeback.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index a3c0cbd7c888..d5815794416c 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -237,6 +237,7 @@ static inline void inode_attach_wb(struct inode *inode, struct page *page)
static inline void inode_detach_wb(struct inode *inode)
{
if (inode->i_wb) {
+ WARN_ON_ONCE(!(inode->i_state & I_CLEAR));
wb_put(inode->i_wb);
inode->i_wb = NULL;
}