Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs dcache updates from Al Viro:
 "Part of this is what the trylock loop elimination series has turned
  into, part making d_move() preserve the parent (and thus the path) of
  victim, plus some general cleanups"

* 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (22 commits)
  d_genocide: move export to definition
  fold dentry_lock_for_move() into its sole caller and clean it up
  make non-exchanging __d_move() copy ->d_parent rather than swap them
  oprofilefs: don't oops on allocation failure
  lustre: get rid of pointless casts to struct dentry *
  debugfs_lookup(): switch to lookup_one_len_unlocked()
  fold lookup_real() into __lookup_hash()
  take out orphan externs (empty_string/slash_string)
  split d_path() and friends into a separate file
  dcache.c: trim includes
  fs/dcache: Avoid a try_lock loop in shrink_dentry_list()
  get rid of trylock loop around dentry_kill()
  handle move to LRU in retain_dentry()
  dput(): consolidate the "do we need to retain it?" into an inlined helper
  split the slow part of lock_parent() off
  now lock_parent() can't run into killed dentry
  get rid of trylock loop in locking dentries on shrink list
  d_delete(): get rid of trylock loop
  fs/dcache: Move dentry_kill() below lock_parent()
  fs/dcache: Remove stale comment from dentry_kill()
  ...

drivers/oprofile/oprofilefs.c

@@ -138,6 +138,9 @@ static int __oprofilefs_create_file(struct dentry *root, char const *name,
 	struct dentry *dentry;
 	struct inode *inode;
 
+	if (!root)
+		return -ENOMEM;
+
 	inode_lock(d_inode(root));
 	dentry = d_alloc_name(root, name);
 	if (!dentry) {

drivers/staging/lustre/lustre/llite/dcache.c

@@ -90,7 +90,7 @@ static int ll_dcompare(const struct dentry *dentry,
 	       d_count(dentry));
 
 	/* mountpoint is always valid */
-	if (d_mountpoint((struct dentry *)dentry))
+	if (d_mountpoint(dentry))
 		return 0;
 
 	if (d_lustre_invalid(dentry))
@@ -111,7 +111,7 @@ static int ll_ddelete(const struct dentry *de)
 	LASSERT(de);
 
 	CDEBUG(D_DENTRY, "%s dentry %pd (%p, parent %p, inode %p) %s%s\n",
-	       d_lustre_invalid((struct dentry *)de) ? "deleting" : "keeping",
+	       d_lustre_invalid(de) ? "deleting" : "keeping",
 	       de, de, de->d_parent, d_inode(de),
 	       d_unhashed(de) ? "" : "hashed,",
 	       list_empty(&de->d_subdirs) ? "" : "subdirs");
@@ -119,7 +119,7 @@ static int ll_ddelete(const struct dentry *de)
 	/* kernel >= 2.6.38 last refcount is decreased after this function. */
 	LASSERT(d_count(de) == 1);
 
-	if (d_lustre_invalid((struct dentry *)de))
+	if (d_lustre_invalid(de))
 		return 1;
 	return 0;
 }

fs/Makefile

@@ -11,7 +11,7 @@ obj-y :=	open.o read_write.o file_table.o super.o \
 		ioctl.o readdir.o select.o dcache.o inode.o \
 		attr.o bad_inode.o file.o filesystems.o namespace.o \
 		seq_file.o xattr.o libfs.o fs-writeback.o \
-		pnode.o splice.o sync.o utimes.o \
+		pnode.o splice.o sync.o utimes.o d_path.o \
 		stack.o fs_struct.o statfs.o fs_pin.o nsfs.o
 
 ifeq ($(CONFIG_BLOCK),y)

fs/debugfs/inode.c

@@ -270,10 +270,7 @@ struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
 	if (!parent)
 		parent = debugfs_mount->mnt_root;
 
-	inode_lock(d_inode(parent));
-	dentry = lookup_one_len(name, parent, strlen(name));
-	inode_unlock(d_inode(parent));
-
+	dentry = lookup_one_len_unlocked(name, parent, strlen(name));
 	if (IS_ERR(dentry))
 		return NULL;
 	if (!d_really_is_positive(dentry)) {

fs/namei.c

@@ -1474,43 +1474,36 @@ static struct dentry *lookup_dcache(const struct qstr *name,
 }
 
 /*
- * Call i_op->lookup on the dentry.  The dentry must be negative and
- * unhashed.
- *
- * dir->d_inode->i_mutex must be held
+ * Parent directory has inode locked exclusive.  This is one
+ * and only case when ->lookup() gets called on non in-lookup
+ * dentries - as the matter of fact, this only gets called
+ * when directory is guaranteed to have no in-lookup children
+ * at all.
  */
-static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry,
-				  unsigned int flags)
-{
-	struct dentry *old;
-
-	/* Don't create child dentry for a dead directory. */
-	if (unlikely(IS_DEADDIR(dir))) {
-		dput(dentry);
-		return ERR_PTR(-ENOENT);
-	}
-
-	old = dir->i_op->lookup(dir, dentry, flags);
-	if (unlikely(old)) {
-		dput(dentry);
-		dentry = old;
-	}
-	return dentry;
-}
-
 static struct dentry *__lookup_hash(const struct qstr *name,
 		struct dentry *base, unsigned int flags)
 {
 	struct dentry *dentry = lookup_dcache(name, base, flags);
+	struct dentry *old;
+	struct inode *dir = base->d_inode;
 
 	if (dentry)
 		return dentry;
 
+	/* Don't create child dentry for a dead directory. */
+	if (unlikely(IS_DEADDIR(dir)))
+		return ERR_PTR(-ENOENT);
+
 	dentry = d_alloc(base, name);
 	if (unlikely(!dentry))
 		return ERR_PTR(-ENOMEM);
 
-	return lookup_real(base->d_inode, dentry, flags);
+	old = dir->i_op->lookup(dir, dentry, flags);
+	if (unlikely(old)) {
+		dput(dentry);
+		dentry = old;
+	}
+	return dentry;
 }
 
 static int lookup_fast(struct nameidata *nd,

include/linux/dcache.h

@@ -56,9 +56,7 @@ struct qstr {
 
 #define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
 
-extern const char empty_string[];
 extern const struct qstr empty_name;
-extern const char slash_string[];
 extern const struct qstr slash_name;
 
 struct dentry_stat_t {
@@ -361,7 +359,7 @@ static inline void dont_mount(struct dentry *dentry)
 
 extern void __d_lookup_done(struct dentry *);
 
-static inline int d_in_lookup(struct dentry *dentry)
+static inline int d_in_lookup(const struct dentry *dentry)
 {
 	return dentry->d_flags & DCACHE_PAR_LOOKUP;
 }
@@ -489,7 +487,7 @@ static inline bool d_really_is_positive(const struct dentry *dentry)
 	return dentry->d_inode != NULL;
 }
 
-static inline int simple_positive(struct dentry *dentry)
+static inline int simple_positive(const struct dentry *dentry)
 {
 	return d_really_is_positive(dentry) && !d_unhashed(dentry);
 }