1 files changed, 40 insertions, 25 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index b1626f269a34..68090e84f589 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -207,7 +207,7 @@ int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf)
         return 0;
 }
 
-static struct pipe_buf_operations anon_pipe_buf_ops = {
+static const struct pipe_buf_operations anon_pipe_buf_ops = {
         .can_merge = 1,
         .map = generic_pipe_buf_map,
         .unmap = generic_pipe_buf_unmap,
@@ -222,7 +222,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
            unsigned long nr_segs, loff_t pos)
 {
         struct file *filp = iocb->ki_filp;
-        struct inode *inode = filp->f_dentry->d_inode;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         struct pipe_inode_info *pipe;
         int do_wakeup;
         ssize_t ret;
@@ -243,7 +243,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
                 if (bufs) {
                         int curbuf = pipe->curbuf;
                         struct pipe_buffer *buf = pipe->bufs + curbuf;
-                        struct pipe_buf_operations *ops = buf->ops;
+                        const struct pipe_buf_operations *ops = buf->ops;
                         void *addr;
                         size_t chars = buf->len;
                         int error, atomic;
@@ -335,7 +335,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
             unsigned long nr_segs, loff_t ppos)
 {
         struct file *filp = iocb->ki_filp;
-        struct inode *inode = filp->f_dentry->d_inode;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         struct pipe_inode_info *pipe;
         ssize_t ret;
         int do_wakeup;
@@ -365,7 +365,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
                 int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &
                                                         (PIPE_BUFFERS-1);
                 struct pipe_buffer *buf = pipe->bufs + lastbuf;
-                struct pipe_buf_operations *ops = buf->ops;
+                const struct pipe_buf_operations *ops = buf->ops;
                 int offset = buf->offset + buf->len;
 
                 if (ops->can_merge && offset + chars <= PAGE_SIZE) {
@@ -520,7 +520,7 @@ static int
 pipe_ioctl(struct inode *pino, struct file *filp,
            unsigned int cmd, unsigned long arg)
 {
-        struct inode *inode = filp->f_dentry->d_inode;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         struct pipe_inode_info *pipe;
         int count, buf, nrbufs;
 
@@ -548,7 +548,7 @@ static unsigned int
 pipe_poll(struct file *filp, poll_table *wait)
 {
         unsigned int mask;
-        struct inode *inode = filp->f_dentry->d_inode;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         struct pipe_inode_info *pipe = inode->i_pipe;
         int nrbufs;
 
@@ -601,7 +601,7 @@ pipe_release(struct inode *inode, int decr, int decw)
 static int
 pipe_read_fasync(int fd, struct file *filp, int on)
 {
-        struct inode *inode = filp->f_dentry->d_inode;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         int retval;
 
         mutex_lock(&inode->i_mutex);
@@ -618,7 +618,7 @@ pipe_read_fasync(int fd, struct file *filp, int on)
 static int
 pipe_write_fasync(int fd, struct file *filp, int on)
 {
-        struct inode *inode = filp->f_dentry->d_inode;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         int retval;
 
         mutex_lock(&inode->i_mutex);
@@ -635,7 +635,7 @@ pipe_write_fasync(int fd, struct file *filp, int on)
 static int
 pipe_rdwr_fasync(int fd, struct file *filp, int on)
 {
-        struct inode *inode = filp->f_dentry->d_inode;
+        struct inode *inode = filp->f_path.dentry->d_inode;
         struct pipe_inode_info *pipe = inode->i_pipe;
         int retval;
 
@@ -756,7 +756,7 @@ const struct file_operations rdwr_fifo_fops = {
         .fasync         = pipe_rdwr_fasync,
 };
 
-static struct file_operations read_pipe_fops = {
+static const struct file_operations read_pipe_fops = {
         .llseek         = no_llseek,
         .read           = do_sync_read,
         .aio_read       = pipe_read,
@@ -768,7 +768,7 @@ static struct file_operations read_pipe_fops = {
         .fasync         = pipe_read_fasync,
 };
 
-static struct file_operations write_pipe_fops = {
+static const struct file_operations write_pipe_fops = {
         .llseek         = no_llseek,
         .read           = bad_pipe_r,
         .write          = do_sync_write,
@@ -780,7 +780,7 @@ static struct file_operations write_pipe_fops = {
         .fasync         = pipe_write_fasync,
 };
 
-static struct file_operations rdwr_pipe_fops = {
+static const struct file_operations rdwr_pipe_fops = {
         .llseek         = no_llseek,
         .read           = do_sync_read,
         .aio_read       = pipe_read,
@@ -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 = {
@@ -891,19 +898,24 @@ 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);
-        f->f_vfsmnt = mntget(pipe_mnt);
-        f->f_dentry = dentry;
+        /*
+         * 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_path.mnt = mntget(pipe_mnt);
+        f->f_path.dentry = dentry;
         f->f_mapping = inode->i_mapping;
 
         f->f_flags = O_WRONLY;
@@ -923,8 +935,9 @@ struct file *create_write_pipe(void)
 
 void free_write_pipe(struct file *f)
 {
-        mntput(f->f_vfsmnt);
-        dput(f->f_dentry);
+        free_pipe_info(f->f_dentry->d_inode);
+        dput(f->f_path.dentry);
+        mntput(f->f_path.mnt);
         put_filp(f);
 }
 
@@ -935,9 +948,9 @@ struct file *create_read_pipe(struct file *wrf)
                 return ERR_PTR(-ENFILE);
 
         /* Grab pipe from the writer */
-        f->f_vfsmnt = mntget(wrf->f_vfsmnt);
-        f->f_dentry = dget(wrf->f_dentry);
-        f->f_mapping = wrf->f_dentry->d_inode->i_mapping;
+        f->f_path.mnt = mntget(wrf->f_path.mnt);
+        f->f_path.dentry = dget(wrf->f_path.dentry);
+        f->f_mapping = wrf->f_path.dentry->d_inode->i_mapping;
 
         f->f_pos = 0;
         f->f_flags = O_RDONLY;
@@ -982,6 +995,8 @@ int do_pipe(int *fd)
  err_fdr:
         put_unused_fd(fdr);
  err_read_pipe:
+        dput(fr->f_dentry);
+        mntput(fr->f_vfsmnt);
         put_filp(fr);
  err_write_pipe:
         free_write_pipe(fw);