Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs updates from Al Viro:
 "overlayfs merge + leak fix for d_splice_alias() failure exits"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  overlayfs: embed middle into overlay_readdir_data
  overlayfs: embed root into overlay_readdir_data
  overlayfs: make ovl_cache_entry->name an array instead of pointer
  overlayfs: don't hold ->i_mutex over opening the real directory
  fix inode leaks on d_splice_alias() failure exits
  fs: limit filesystem stacking depth
  overlay: overlay filesystem documentation
  overlayfs: implement show_options
  overlayfs: add statfs support
  overlay filesystem
  shmem: support RENAME_WHITEOUT
  ext4: support RENAME_WHITEOUT
  vfs: add RENAME_WHITEOUT
  vfs: add whiteout support
  vfs: export check_sticky()
  vfs: introduce clone_private_mount()
  vfs: export __inode_permission() to modules
  vfs: export do_splice_direct() to modules
  vfs: add i_op->dentry_open()

1 files changed, 35 insertions, 1 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index cd6fc7590e54..185836ba53ef 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2345,6 +2345,32 @@ static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, stru
         return 0;
 }
 
+static int shmem_whiteout(struct inode *old_dir, struct dentry *old_dentry)
+{
+        struct dentry *whiteout;
+        int error;
+
+        whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
+        if (!whiteout)
+                return -ENOMEM;
+
+        error = shmem_mknod(old_dir, whiteout,
+                            S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);
+        dput(whiteout);
+        if (error)
+                return error;
+
+        /*
+         * Cheat and hash the whiteout while the old dentry is still in
+         * place, instead of playing games with FS_RENAME_DOES_D_MOVE.
+         *
+         * d_lookup() will consistently find one of them at this point,
+         * not sure which one, but that isn't even important.
+         */
+        d_rehash(whiteout);
+        return 0;
+}
+
 /*
  * The VFS layer already does all the dentry stuff for rename,
  * we just have to decrement the usage count for the target if
@@ -2356,7 +2382,7 @@ static int shmem_rename2(struct inode *old_dir, struct dentry *old_dentry, struc
         struct inode *inode = old_dentry->d_inode;
         int they_are_dirs = S_ISDIR(inode->i_mode);
 
-        if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
+        if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
                 return -EINVAL;
 
         if (flags & RENAME_EXCHANGE)
@@ -2365,6 +2391,14 @@ static int shmem_rename2(struct inode *old_dir, struct dentry *old_dentry, struc
         if (!simple_empty(new_dentry))
                 return -ENOTEMPTY;
 
+        if (flags & RENAME_WHITEOUT) {
+                int error;
+
+                error = shmem_whiteout(old_dir, old_dentry);
+                if (error)
+                        return error;
+        }
+
         if (new_dentry->d_inode) {
                 (void) shmem_unlink(new_dir, new_dentry);
                 if (they_are_dirs) {