1 files changed, 17 insertions, 5 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index b1626f269a34..ae36b89b1a37 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -830,7 +830,14 @@ void free_pipe_info(struct inode *inode)
 static struct vfsmount *pipe_mnt __read_mostly;
 static int pipefs_delete_dentry(struct dentry *dentry)
 {
-        return 1;
+        /*
+         * At creation time, we pretended this dentry was hashed
+         * (by clearing DCACHE_UNHASHED bit in d_flags)
+         * At delete time, we restore the truth : not hashed.
+         * (so that dput() can proceed correctly)
+         */
+        dentry->d_flags |= DCACHE_UNHASHED;
+        return 0;
 }
 
 static struct dentry_operations pipefs_dentry_operations = {
@@ -891,17 +898,22 @@ struct file *create_write_pipe(void)
         if (!inode)
                 goto err_file;
 
-        sprintf(name, "[%lu]", inode->i_ino);
+        this.len = sprintf(name, "[%lu]", inode->i_ino);
         this.name = name;
-        this.len = strlen(name);
-        this.hash = inode->i_ino; /* will go */
+        this.hash = 0;
         err = -ENOMEM;
         dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this);
         if (!dentry)
                 goto err_inode;
 
         dentry->d_op = &pipefs_dentry_operations;
-        d_add(dentry, inode);
+        /*
+         * We dont want to publish this dentry into global dentry hash table.
+         * We pretend dentry is already hashed, by unsetting DCACHE_UNHASHED
+         * This permits a working /proc/$pid/fd/XXX on pipes
+         */
+        dentry->d_flags &= ~DCACHE_UNHASHED;
+        d_instantiate(dentry, inode);
         f->f_vfsmnt = mntget(pipe_mnt);
         f->f_dentry = dentry;
         f->f_mapping = inode->i_mapping;