| From 72651cac884b1e285fa8e8314b10e9f1b8458802 Mon Sep 17 00:00:00 2001 |
| From: Jan Kara <jack@suse.cz> |
| Date: Wed, 5 Dec 2012 14:40:14 +0100 |
| Subject: fs: Fix imbalance in freeze protection in mark_files_ro() |
| |
| From: Jan Kara <jack@suse.cz> |
| |
| commit 72651cac884b1e285fa8e8314b10e9f1b8458802 upstream. |
| |
| File descriptors (even those for writing) do not hold freeze protection. |
| Thus mark_files_ro() must call __mnt_drop_write() to only drop protection |
| against remount read-only. Calling mnt_drop_write_file() as we do now |
| results in: |
| |
| [ BUG: bad unlock balance detected! ] |
| 3.7.0-rc6-00028-g88e75b6 #101 Not tainted |
| ------------------------------------- |
| kworker/1:2/79 is trying to release lock (sb_writers) at: |
| [<ffffffff811b33b4>] mnt_drop_write+0x24/0x30 |
| but there are no more locks to release! |
| |
| Reported-by: Zdenek Kabelac <zkabelac@redhat.com> |
| Signed-off-by: Jan Kara <jack@suse.cz> |
| Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/file_table.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/file_table.c |
| +++ b/fs/file_table.c |
| @@ -458,8 +458,8 @@ void mark_files_ro(struct super_block *s |
| spin_unlock(&f->f_lock); |
| if (file_check_writeable(f) != 0) |
| continue; |
| + __mnt_drop_write(f->f_path.mnt); |
| file_release_write(f); |
| - mnt_drop_write_file(f); |
| } while_file_list_for_each_entry; |
| lg_global_unlock(&files_lglock); |
| } |
