fs: dcache remove dcache_lock

dcache_lock no longer protects anything. remove it.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

5 files changed, 14 insertions, 11 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index c963ebada922..a2ceb94b0e38 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -183,7 +183,6 @@ struct dentry_operations {
 #define DCACHE_GENOCIDE         0x0200
 
 extern spinlock_t dcache_inode_lock;
-extern spinlock_t dcache_lock;
 extern seqlock_t rename_lock;
 
 static inline int dname_external(struct dentry *dentry)
@@ -296,8 +295,8 @@ extern char *dentry_path(struct dentry *, char *, int);
  *      destroyed when it has references. dget() should never be
  *      called for dentries with zero reference counter. For these cases
  *      (preferably none, functions in dcache.c are sufficient for normal
- *      needs and they take necessary precautions) you should hold dcache_lock
- *      and call dget_locked() instead of dget().
+ *      needs and they take necessary precautions) you should hold d_lock
+ *      and call dget_dlock() instead of dget().
  */
 static inline struct dentry *dget_dlock(struct dentry *dentry)
 {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 090f0eacde29..296cf2fde945 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1378,7 +1378,7 @@ struct super_block {
 #else
         struct list_head        s_files;
 #endif
-        /* s_dentry_lru and s_nr_dentry_unused are protected by dcache_lock */
+        /* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */
         struct list_head        s_dentry_lru;   /* unused dentry lru */
         int                     s_nr_dentry_unused;     /* # of dentry on lru */
 
@@ -2446,6 +2446,10 @@ static inline ino_t parent_ino(struct dentry *dentry)
 {
         ino_t res;
 
+        /*
+         * Don't strictly need d_lock here? If the parent ino could change
+         * then surely we'd have a deeper race in the caller?
+         */
         spin_lock(&dentry->d_lock);
         res = dentry->d_parent->d_inode->i_ino;
         spin_unlock(&dentry->d_lock);
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index b10bcdeaef76..2a53f10712b3 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -17,7 +17,6 @@
 
 /*
  * fsnotify_d_instantiate - instantiate a dentry for inode
- * Called with dcache_lock held.
  */
 static inline void fsnotify_d_instantiate(struct dentry *dentry,
                                           struct inode *inode)
@@ -62,7 +61,6 @@ static inline int fsnotify_perm(struct file *file, int mask)
 
 /*
  * fsnotify_d_move - dentry has been moved
- * Called with dcache_lock and dentry->d_lock held.
  */
 static inline void fsnotify_d_move(struct dentry *dentry)
 {
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 7380763595d3..69ad89b50489 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -329,9 +329,15 @@ static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
 {
         struct dentry *parent;
 
-        assert_spin_locked(&dcache_lock);
         assert_spin_locked(&dentry->d_lock);
 
+        /*
+         * Serialisation of setting PARENT_WATCHED on the dentries is provided
+         * by d_lock. If inotify_inode_watched changes after we have taken
+         * d_lock, the following __fsnotify_update_child_dentry_flags call will
+         * find our entry, so it will spin until we complete here, and update
+         * us with the new state.
+         */
         parent = dentry->d_parent;
         if (parent->d_inode && fsnotify_inode_watches_children(parent->d_inode))
                 dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
@@ -341,15 +347,12 @@ static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
 
 /*
  * fsnotify_d_instantiate - instantiate a dentry for inode
- * Called with dcache_lock held.
  */
 static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
 {
         if (!inode)
                 return;
 
-        assert_spin_locked(&dcache_lock);
-
         spin_lock(&dentry->d_lock);
         __fsnotify_update_dcache_flags(dentry);
         spin_unlock(&dentry->d_lock);
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 05b441d93642..aec730b53935 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -41,7 +41,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
  *  - require a directory
  *  - ending slashes ok even for nonexistent files
  *  - internal "there are more path components" flag
- *  - locked when lookup done with dcache_lock held
  *  - dentry cache is untrusted; force a real lookup
  */
 #define LOOKUP_FOLLOW            1