ceph: use i_ceph_lock instead of i_lock

We have been using i_lock to protect all kinds of data structures in the
ceph_inode_info struct, including lists of inodes that we need to iterate
over while avoiding races with inode destruction.  That requires grabbing
a reference to the inode with the list lock protected, but igrab() now
takes i_lock to check the inode flags.

Changing the list lock ordering would be a painful process.

However, using a ceph-specific i_ceph_lock in the ceph inode instead of
i_lock is a simple mechanical change and avoids the ordering constraints
imposed by igrab().

Reported-by: Amon Ott <a.ott@m-privacy.de>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
index 5a14c29cbba6..790914a598dd 100644
--- a/fs/ceph/ioctl.c
+++ b/fs/ceph/ioctl.c
@@ -241,11 +241,11 @@ static long ceph_ioctl_lazyio(struct file *file)
         struct ceph_inode_info *ci = ceph_inode(inode);
 
         if ((fi->fmode & CEPH_FILE_MODE_LAZY) == 0) {
-                spin_lock(&inode->i_lock);
+                spin_lock(&ci->i_ceph_lock);
                 ci->i_nr_by_mode[fi->fmode]--;
                 fi->fmode |= CEPH_FILE_MODE_LAZY;
                 ci->i_nr_by_mode[fi->fmode]++;
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
                 dout("ioctl_layzio: file %p marked lazy\n", file);
 
                 ceph_check_caps(ci, 0, NULL);