1 files changed, 24 insertions, 11 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 9858f337529c..fe7afe225381 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -11,10 +11,8 @@ be able to use diff(1).
 prototypes:
         int (*d_revalidate)(struct dentry *, unsigned int);
         int (*d_weak_revalidate)(struct dentry *, unsigned int);
-        int (*d_hash)(const struct dentry *, const struct inode *,
-                        struct qstr *);
-        int (*d_compare)(const struct dentry *, const struct inode *,
-                        const struct dentry *, const struct inode *,
+        int (*d_hash)(const struct dentry *, struct qstr *);
+        int (*d_compare)(const struct dentry *, const struct dentry *,
                         unsigned int, const char *, const struct qstr *);
         int (*d_delete)(struct dentry *);
         void (*d_release)(struct dentry *);
@@ -66,6 +64,7 @@ prototypes:
         int (*atomic_open)(struct inode *, struct dentry *,
                                 struct file *, unsigned open_flag,
                                 umode_t create_mode, int *opened);
+        int (*tmpfile) (struct inode *, struct dentry *, umode_t);
 
 locking rules:
         all may block
@@ -93,6 +92,7 @@ removexattr:	yes
 fiemap:         no
 update_time:    no
 atomic_open:    yes
+tmpfile:        no
 
         Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
 victim.
@@ -344,25 +344,38 @@ prototypes:
 
 
 locking rules:
-                        file_lock_lock  may block
+                        inode->i_lock   may block
 fl_copy_lock:           yes             no
 fl_release_private:     maybe           no
 
 ----------------------- lock_manager_operations ---------------------------
 prototypes:
         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
+        unsigned long (*lm_owner_key)(struct file_lock *);
         void (*lm_notify)(struct file_lock *);  /* unblock callback */
         int (*lm_grant)(struct file_lock *, struct file_lock *, int);
         void (*lm_break)(struct file_lock *); /* break_lease callback */
         int (*lm_change)(struct file_lock **, int);
 
 locking rules:
-                        file_lock_lock  may block
-lm_compare_owner:       yes             no
-lm_notify:              yes             no
-lm_grant:               no              no
-lm_break:               yes             no
-lm_change               yes             no
+
+                        inode->i_lock   blocked_lock_lock       may block
+lm_compare_owner:       yes[1]          maybe                   no
+lm_owner_key            yes[1]          yes                     no
+lm_notify:              yes             yes                     no
+lm_grant:               no              no                      no
+lm_break:               yes             no                      no
+lm_change               yes             no                      no
+
+[1]:    ->lm_compare_owner and ->lm_owner_key are generally called with
+*an* inode->i_lock held. It may not be the i_lock of the inode
+associated with either file_lock argument! This is the case with deadlock
+detection, since the code has to chase down the owners of locks that may
+be entirely unrelated to the one on which the lock is being acquired.
+For deadlock detection however, the blocked_lock_lock is also held. The
+fact that these locks are held ensures that the file_locks do not
+disappear out from under you while doing the comparison or generating an
+owner key.
 
 --------------------------- buffer_head -----------------------------------
 prototypes: