fs: Add freezing handling to mnt_want_write() / mnt_drop_write()

Most of places where we want freeze protection coincides with the places where
we also have remount-ro protection. So make mnt_want_write() and
mnt_drop_write() (and their _file alternative) prevent freezing as well.
For the few cases that are really interested only in remount-ro protection
provide new function variants.

BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 775cbabd4fa5..006c85ca06eb 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1660,11 +1660,11 @@ int file_update_time(struct file *file)
                 return 0;
 
         /* Finally allowed to write? Takes lock. */
-        if (mnt_want_write_file(file))
+        if (__mnt_want_write_file(file))
                 return 0;
 
         ret = update_time(inode, &now, sync_it);
-        mnt_drop_write_file(file);
+        __mnt_drop_write_file(file);
 
         return ret;
 }