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, 16 insertions, 16 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 264ab701154f..34bc35084ae3 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -732,21 +732,21 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
                 }
         }
 
-        spin_lock(&inode->i_lock);
+        spin_lock(&ci->i_ceph_lock);
         cap = NULL;
         if (mode == USE_AUTH_MDS)
                 cap = ci->i_auth_cap;
         if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
                 cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
         if (!cap) {
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
                 goto random;
         }
         mds = cap->session->s_mds;
         dout("choose_mds %p %llx.%llx mds%d (%scap %p)\n",
              inode, ceph_vinop(inode), mds,
              cap == ci->i_auth_cap ? "auth " : "", cap);
-        spin_unlock(&inode->i_lock);
+        spin_unlock(&ci->i_ceph_lock);
         return mds;
 
 random:
@@ -951,7 +951,7 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
 
         dout("removing cap %p, ci is %p, inode is %p\n",
              cap, ci, &ci->vfs_inode);
-        spin_lock(&inode->i_lock);
+        spin_lock(&ci->i_ceph_lock);
         __ceph_remove_cap(cap);
         if (!__ceph_is_any_real_caps(ci)) {
                 struct ceph_mds_client *mdsc =
@@ -984,7 +984,7 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
                 }
                 spin_unlock(&mdsc->cap_dirty_lock);
         }
-        spin_unlock(&inode->i_lock);
+        spin_unlock(&ci->i_ceph_lock);
         while (drop--)
                 iput(inode);
         return 0;
@@ -1015,10 +1015,10 @@ static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
 
         wake_up_all(&ci->i_cap_wq);
         if (arg) {
-                spin_lock(&inode->i_lock);
+                spin_lock(&ci->i_ceph_lock);
                 ci->i_wanted_max_size = 0;
                 ci->i_requested_max_size = 0;
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
         }
         return 0;
 }
@@ -1151,7 +1151,7 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
         if (session->s_trim_caps <= 0)
                 return -1;
 
-        spin_lock(&inode->i_lock);
+        spin_lock(&ci->i_ceph_lock);
         mine = cap->issued | cap->implemented;
         used = __ceph_caps_used(ci);
         oissued = __ceph_caps_issued_other(ci, cap);
@@ -1170,7 +1170,7 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
                 __ceph_remove_cap(cap);
         } else {
                 /* try to drop referring dentries */
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
                 d_prune_aliases(inode);
                 dout("trim_caps_cb %p cap %p  pruned, count now %d\n",
                      inode, cap, atomic_read(&inode->i_count));
@@ -1178,7 +1178,7 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
         }
 
 out:
-        spin_unlock(&inode->i_lock);
+        spin_unlock(&ci->i_ceph_lock);
         return 0;
 }
 
@@ -1296,7 +1296,7 @@ static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
                                            i_flushing_item);
                         struct inode *inode = &ci->vfs_inode;
 
-                        spin_lock(&inode->i_lock);
+                        spin_lock(&ci->i_ceph_lock);
                         if (ci->i_cap_flush_seq <= want_flush_seq) {
                                 dout("check_cap_flush still flushing %p "
                                      "seq %lld <= %lld to mds%d\n", inode,
@@ -1304,7 +1304,7 @@ static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
                                      session->s_mds);
                                 ret = 0;
                         }
-                        spin_unlock(&inode->i_lock);
+                        spin_unlock(&ci->i_ceph_lock);
                 }
                 mutex_unlock(&session->s_mutex);
                 ceph_put_mds_session(session);
@@ -2011,10 +2011,10 @@ void ceph_invalidate_dir_request(struct ceph_mds_request *req)
         struct ceph_inode_info *ci = ceph_inode(inode);
 
         dout("invalidate_dir_request %p (D_COMPLETE, lease(s))\n", inode);
-        spin_lock(&inode->i_lock);
+        spin_lock(&ci->i_ceph_lock);
         ceph_dir_clear_complete(inode);
         ci->i_release_count++;
-        spin_unlock(&inode->i_lock);
+        spin_unlock(&ci->i_ceph_lock);
 
         if (req->r_dentry)
                 ceph_invalidate_dentry_lease(req->r_dentry);
@@ -2422,7 +2422,7 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
         if (err)
                 goto out_free;
 
-        spin_lock(&inode->i_lock);
+        spin_lock(&ci->i_ceph_lock);
         cap->seq = 0;        /* reset cap seq */
         cap->issue_seq = 0;  /* and issue_seq */
 
@@ -2445,7 +2445,7 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
                 rec.v1.pathbase = cpu_to_le64(pathbase);
                 reclen = sizeof(rec.v1);
         }
-        spin_unlock(&inode->i_lock);
+        spin_unlock(&ci->i_ceph_lock);
 
         if (recon_state->flock) {
                 int num_fcntl_locks, num_flock_locks;