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

Pull vfs mount updates from Al Viro:
 "Several piles this cycle, this mount-related one being the largest and
  trickiest:

   - saner handling of guards in fs/namespace.c, getting rid of
     needlessly strong locking in some of the users

   - lock_mount() calling conventions change - have it set the
     environment for attaching to given location, storing the results in
     caller-supplied object, without altering the passed struct path.

     Make unlock_mount() called as __cleanup for those objects. It's not
     exactly guard(), but similar to it

   - MNT_WRITE_HOLD done right.

     mnt_hold_writers() does *not* mess with ->mnt_flags anymore, so
     insertion of a new mount into ->s_mounts of underlying superblock
     does not, in itself, expose ->mnt_flags of that mount to concurrent
     modifications

   - getting rid of pathological cases when umount() spends quadratic
     time removing the victims from propagation graph - part of that had
     been dealt with last cycle, this should finish it

   - a bunch of stuff constified

   - assorted cleanups

* tag 'pull-mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
  constify {__,}mnt_is_readonly()
  WRITE_HOLD machinery: no need for to bump mount_lock seqcount
  struct mount: relocate MNT_WRITE_HOLD bit
  preparations to taking MNT_WRITE_HOLD out of ->mnt_flags
  setup_mnt(): primitive for connecting a mount to filesystem
  simplify the callers of mnt_unhold_writers()
  copy_mnt_ns(): use guards
  copy_mnt_ns(): use the regular mechanism for freeing empty mnt_ns on failure
  open_detached_copy(): separate creation of namespace into helper
  open_detached_copy(): don't bother with mount_lock_hash()
  path_has_submounts(): use guard(mount_locked_reader)
  fs/namespace.c: sanitize descriptions for {__,}lookup_mnt()
  ecryptfs: get rid of pointless mount references in ecryptfs dentries
  umount_tree(): take all victims out of propagation graph at once
  do_mount(): use __free(path_put)
  do_move_mount_old(): use __free(path_put)
  constify can_move_mount_beneath() arguments
  path_umount(): constify struct path argument
  may_copy_tree(), __do_loopback(): constify struct path argument
  path_mount(): constify struct path argument
  ...

1 files changed, 11 insertions, 16 deletions

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 1f562e75d0e4..9e6ab0b41337 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -258,13 +258,6 @@ struct ecryptfs_inode_info {
 	struct ecryptfs_crypt_stat crypt_stat;
 };
 
-/* dentry private data. Each dentry must keep track of a lower
- * vfsmount too. */
-struct ecryptfs_dentry_info {
-	struct path lower_path;
-	struct rcu_head rcu;
-};
-
 /**
  * ecryptfs_global_auth_tok - A key used to encrypt all new files under the mountpoint
  * @flags: Status flags
@@ -348,6 +341,7 @@ struct ecryptfs_mount_crypt_stat {
 /* superblock private data. */
 struct ecryptfs_sb_info {
 	struct super_block *wsi_sb;
+	struct vfsmount *lower_mnt;
 	struct ecryptfs_mount_crypt_stat mount_crypt_stat;
 };
 
@@ -494,22 +488,25 @@ ecryptfs_set_superblock_lower(struct super_block *sb,
 }
 
 static inline void
-ecryptfs_set_dentry_private(struct dentry *dentry,
-			    struct ecryptfs_dentry_info *dentry_info)
+ecryptfs_set_dentry_lower(struct dentry *dentry,
+			  struct dentry *lower_dentry)
 {
-	dentry->d_fsdata = dentry_info;
+	dentry->d_fsdata = lower_dentry;
 }
 
 static inline struct dentry *
 ecryptfs_dentry_to_lower(struct dentry *dentry)
 {
-	return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry;
+	return dentry->d_fsdata;
 }
 
-static inline const struct path *
-ecryptfs_dentry_to_lower_path(struct dentry *dentry)
+static inline struct path
+ecryptfs_lower_path(struct dentry *dentry)
 {
-	return &((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path;
+	return (struct path){
+		.mnt = ecryptfs_superblock_to_private(dentry->d_sb)->lower_mnt,
+		.dentry = ecryptfs_dentry_to_lower(dentry)
+	};
 }
 
 #define ecryptfs_printk(type, fmt, arg...) \
@@ -532,7 +529,6 @@ extern unsigned int ecryptfs_number_of_users;
 
 extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
 extern struct kmem_cache *ecryptfs_file_info_cache;
-extern struct kmem_cache *ecryptfs_dentry_info_cache;
 extern struct kmem_cache *ecryptfs_inode_info_cache;
 extern struct kmem_cache *ecryptfs_sb_info_cache;
 extern struct kmem_cache *ecryptfs_header_cache;
@@ -557,7 +553,6 @@ int ecryptfs_encrypt_and_encode_filename(
 	size_t *encoded_name_size,
 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 	const char *name, size_t name_size);
-struct dentry *ecryptfs_lower_dentry(struct dentry *this_dentry);
 void ecryptfs_dump_hex(char *data, int bytes);
 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
 			int sg_size);