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, 10 insertions, 10 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index ce549d31eeb7..af187330cc89 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -147,9 +147,9 @@ int ceph_open(struct inode *inode, struct file *file)
 
         /* trivially open snapdir */
         if (ceph_snap(inode) == CEPH_SNAPDIR) {
-                spin_lock(&inode->i_lock);
+                spin_lock(&ci->i_ceph_lock);
                 __ceph_get_fmode(ci, fmode);
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
                 return ceph_init_file(inode, file, fmode);
         }
 
@@ -158,7 +158,7 @@ int ceph_open(struct inode *inode, struct file *file)
          * write) or any MDS (for read).  Update wanted set
          * asynchronously.
          */
-        spin_lock(&inode->i_lock);
+        spin_lock(&ci->i_ceph_lock);
         if (__ceph_is_any_real_caps(ci) &&
             (((fmode & CEPH_FILE_MODE_WR) == 0) || ci->i_auth_cap)) {
                 int mds_wanted = __ceph_caps_mds_wanted(ci);
@@ -168,7 +168,7 @@ int ceph_open(struct inode *inode, struct file *file)
                      inode, fmode, ceph_cap_string(wanted),
                      ceph_cap_string(issued));
                 __ceph_get_fmode(ci, fmode);
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
 
                 /* adjust wanted? */
                 if ((issued & wanted) != wanted &&
@@ -180,10 +180,10 @@ int ceph_open(struct inode *inode, struct file *file)
         } else if (ceph_snap(inode) != CEPH_NOSNAP &&
                    (ci->i_snap_caps & wanted) == wanted) {
                 __ceph_get_fmode(ci, fmode);
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
                 return ceph_init_file(inode, file, fmode);
         }
-        spin_unlock(&inode->i_lock);
+        spin_unlock(&ci->i_ceph_lock);
 
         dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
         req = prepare_open_request(inode->i_sb, flags, 0);
@@ -743,9 +743,9 @@ retry_snap:
                  */
                 int dirty;
 
-                spin_lock(&inode->i_lock);
+                spin_lock(&ci->i_ceph_lock);
                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
                 ceph_put_cap_refs(ci, got);
 
                 ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
@@ -764,9 +764,9 @@ retry_snap:
 
         if (ret >= 0) {
                 int dirty;
-                spin_lock(&inode->i_lock);
+                spin_lock(&ci->i_ceph_lock);
                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
-                spin_unlock(&inode->i_lock);
+                spin_unlock(&ci->i_ceph_lock);
                 if (dirty)
                         __mark_inode_dirty(inode, dirty);
         }