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>
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index e264371..a559c80 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -446,7 +446,7 @@
return;
}
- spin_lock(&inode->i_lock);
+ spin_lock(&ci->i_ceph_lock);
used = __ceph_caps_used(ci);
dirty = __ceph_caps_dirty(ci);
@@ -528,7 +528,7 @@
kfree(capsnap);
}
- spin_unlock(&inode->i_lock);
+ spin_unlock(&ci->i_ceph_lock);
}
/*
@@ -537,7 +537,7 @@
*
* If capsnap can now be flushed, add to snap_flush list, and return 1.
*
- * Caller must hold i_lock.
+ * Caller must hold i_ceph_lock.
*/
int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
struct ceph_cap_snap *capsnap)
@@ -739,9 +739,9 @@
inode = &ci->vfs_inode;
ihold(inode);
spin_unlock(&mdsc->snap_flush_lock);
- spin_lock(&inode->i_lock);
+ spin_lock(&ci->i_ceph_lock);
__ceph_flush_snaps(ci, &session, 0);
- spin_unlock(&inode->i_lock);
+ spin_unlock(&ci->i_ceph_lock);
iput(inode);
spin_lock(&mdsc->snap_flush_lock);
}
@@ -847,7 +847,7 @@
continue;
ci = ceph_inode(inode);
- spin_lock(&inode->i_lock);
+ spin_lock(&ci->i_ceph_lock);
if (!ci->i_snap_realm)
goto skip_inode;
/*
@@ -876,7 +876,7 @@
oldrealm = ci->i_snap_realm;
ci->i_snap_realm = realm;
spin_unlock(&realm->inodes_with_caps_lock);
- spin_unlock(&inode->i_lock);
+ spin_unlock(&ci->i_ceph_lock);
ceph_get_snap_realm(mdsc, realm);
ceph_put_snap_realm(mdsc, oldrealm);
@@ -885,7 +885,7 @@
continue;
skip_inode:
- spin_unlock(&inode->i_lock);
+ spin_unlock(&ci->i_ceph_lock);
iput(inode);
}