Merge tag 'pull-revalidate' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs d_revalidate updates from Al Viro:
 "Provide stable parent and name to ->d_revalidate() instances

  Most of the filesystem methods where we care about dentry name and
  parent have their stability guaranteed by the callers;
  ->d_revalidate() is the major exception.

  It's easy enough for callers to supply stable values for expected name
  and expected parent of the dentry being validated. That kills quite a
  bit of boilerplate in ->d_revalidate() instances, along with a bunch
  of races where they used to access ->d_name without sufficient
  precautions"

* tag 'pull-revalidate' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  9p: fix ->rename_sem exclusion
  orangefs_d_revalidate(): use stable parent inode and name passed by caller
  ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller
  nfs: fix ->d_revalidate() UAF on ->d_name accesses
  nfs{,4}_lookup_validate(): use stable parent inode passed by caller
  gfs2_drevalidate(): use stable parent inode and name passed by caller
  fuse_dentry_revalidate(): use stable parent inode and name passed by caller
  vfat_revalidate{,_ci}(): use stable parent inode passed by caller
  exfat_d_revalidate(): use stable parent inode passed by caller
  fscrypt_d_revalidate(): use stable parent inode passed by caller
  ceph_d_revalidate(): propagate stable name down into request encoding
  ceph_d_revalidate(): use stable parent inode passed by caller
  afs_d_revalidate(): use stable name and parent inode passed by caller
  Pass parent directory inode and expected name to ->d_revalidate()
  generic_ci_d_compare(): use shortname_storage
  ext4 fast_commit: make use of name_snapshot primitives
  dissolve external_name.u into separate members
  make take_dentry_name_snapshot() lockless
  dcache: back inline names with a struct-wrapped array of unsigned long
  make sure that DNAME_INLINE_LEN is a multiple of word size

3 files changed, 22 insertions, 10 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index bff956f7b2b9..9a1a30857763 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -68,16 +68,24 @@ extern const struct qstr dotdot_name;
  * large memory footprint increase).
  */
 #ifdef CONFIG_64BIT
-# define DNAME_INLINE_LEN 40 /* 192 bytes */
+# define DNAME_INLINE_WORDS 5 /* 192 bytes */
 #else
 # ifdef CONFIG_SMP
-#  define DNAME_INLINE_LEN 36 /* 128 bytes */
+#  define DNAME_INLINE_WORDS 9 /* 128 bytes */
 # else
-#  define DNAME_INLINE_LEN 44 /* 128 bytes */
+#  define DNAME_INLINE_WORDS 11 /* 128 bytes */
 # endif
 #endif
 
+#define DNAME_INLINE_LEN (DNAME_INLINE_WORDS*sizeof(unsigned long))
+
+union shortname_store {
+	unsigned char string[DNAME_INLINE_LEN];
+	unsigned long words[DNAME_INLINE_WORDS];
+};
+
 #define d_lock	d_lockref.lock
+#define d_iname d_shortname.string
 
 struct dentry {
 	/* RCU lookup touched fields */
@@ -88,7 +96,7 @@ struct dentry {
 	struct qstr d_name;
 	struct inode *d_inode;		/* Where the name belongs to - NULL is
 					 * negative */
-	unsigned char d_iname[DNAME_INLINE_LEN];	/* small names */
+	union shortname_store d_shortname;
 	/* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */
 
 	/* Ref lookup also touches following */
@@ -136,7 +144,8 @@ enum d_real_type {
 };
 
 struct dentry_operations {
-	int (*d_revalidate)(struct dentry *, unsigned int);
+	int (*d_revalidate)(struct inode *, const struct qstr *,
+			    struct dentry *, unsigned int);
 	int (*d_weak_revalidate)(struct dentry *, unsigned int);
 	int (*d_hash)(const struct dentry *, struct qstr *);
 	int (*d_compare)(const struct dentry *,
@@ -150,6 +159,8 @@ struct dentry_operations {
 	struct vfsmount *(*d_automount)(struct path *);
 	int (*d_manage)(const struct path *, bool);
 	struct dentry *(*d_real)(struct dentry *, enum d_real_type type);
+	bool (*d_unalias_trylock)(const struct dentry *);
+	void (*d_unalias_unlock)(const struct dentry *);
 } ____cacheline_aligned;
 
 /*
@@ -589,7 +600,7 @@ static inline struct inode *d_real_inode(const struct dentry *dentry)
 
 struct name_snapshot {
 	struct qstr name;
-	unsigned char inline_name[DNAME_INLINE_LEN];
+	union shortname_store inline_name;
 };
 void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
 void release_dentry_name_snapshot(struct name_snapshot *);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 772f822dc6b8..18855cb44b1c 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -192,7 +192,8 @@ struct fscrypt_operations {
 					     unsigned int *num_devs);
 };
 
-int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
+int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
+			 struct dentry *dentry, unsigned int flags);
 
 static inline struct fscrypt_inode_info *
 fscrypt_get_inode_info(const struct inode *inode)
@@ -711,8 +712,8 @@ static inline u64 fscrypt_fname_siphash(const struct inode *dir,
 	return 0;
 }
 
-static inline int fscrypt_d_revalidate(struct dentry *dentry,
-				       unsigned int flags)
+static inline int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
+				       struct dentry *dentry, unsigned int flags)
 {
 	return 1;
 }
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 162b7c0c3555..9155a6ffc370 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1781,7 +1781,7 @@ struct nfs_rpc_ops {
 			    struct nfs_fattr *, struct inode *);
 	int	(*setattr) (struct dentry *, struct nfs_fattr *,
 			    struct iattr *);
-	int	(*lookup)  (struct inode *, struct dentry *,
+	int	(*lookup)  (struct inode *, struct dentry *, const struct qstr *,
 			    struct nfs_fh *, struct nfs_fattr *);
 	int	(*lookupp) (struct inode *, struct nfs_fh *,
 			    struct nfs_fattr *);