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authorBoaz Harrosh <bharrosh@panasas.com>2011-02-10 15:01:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-02-11 16:12:19 -0800
commitd863b50ab01333659314c2034890cb76d9fdc3c7 (patch)
tree88d27ed4717bb49ba696f2efb5ef024388412af3
parent2dab597441667d6c04451a7dcf215241ad4c74f6 (diff)
vfs: call rcu_barrier after ->kill_sb()
In commit fa0d7e3de6d6 ("fs: icache RCU free inodes"), we use rcu free inode instead of freeing the inode directly. It causes a crash when we rmmod immediately after we umount the volume[1]. So we need to call rcu_barrier after we kill_sb so that the inode is freed before we do rmmod. The idea is inspired by Aneesh Kumar. rcu_barrier will wait for all callbacks to end before preceding. The original patch was done by Tao Ma, but synchronize_rcu() is not enough here. 1. http://marc.info/?l=linux-fsdevel&m=129680863330185&w=2 Tested-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/super.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/super.c b/fs/super.c
index 74e149efed8..7e9dd4cc2c0 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -177,6 +177,11 @@ void deactivate_locked_super(struct super_block *s)
struct file_system_type *fs = s->s_type;
if (atomic_dec_and_test(&s->s_active)) {
fs->kill_sb(s);
+ /*
+ * We need to call rcu_barrier so all the delayed rcu free
+ * inodes are flushed before we release the fs module.
+ */
+ rcu_barrier();
put_filesystem(fs);
put_super(s);
} else {