1 files changed, 236 insertions, 224 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index bd3479db4b62..d2c45e14e6d8 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -21,10 +21,13 @@
 #include <linux/audit.h>
 #include <linux/syscalls.h>
 #include <linux/fcntl.h>
+#include <linux/aio.h>
 
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>
 
+#include "internal.h"
+
 /*
  * The max size that a non-root user is allowed to grow the pipe. Can
  * be set by root in /proc/sys/fs/pipe-max-size
@@ -53,8 +56,8 @@ unsigned int pipe_min_size = PAGE_SIZE;
 
 static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass)
 {
-        if (pipe->inode)
-                mutex_lock_nested(&pipe->inode->i_mutex, subclass);
+        if (pipe->files)
+                mutex_lock_nested(&pipe->mutex, subclass);
 }
 
 void pipe_lock(struct pipe_inode_info *pipe)
@@ -68,11 +71,21 @@ EXPORT_SYMBOL(pipe_lock);
 
 void pipe_unlock(struct pipe_inode_info *pipe)
 {
-        if (pipe->inode)
-                mutex_unlock(&pipe->inode->i_mutex);
+        if (pipe->files)
+                mutex_unlock(&pipe->mutex);
 }
 EXPORT_SYMBOL(pipe_unlock);
 
+static inline void __pipe_lock(struct pipe_inode_info *pipe)
+{
+        mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT);
+}
+
+static inline void __pipe_unlock(struct pipe_inode_info *pipe)
+{
+        mutex_unlock(&pipe->mutex);
+}
+
 void pipe_double_lock(struct pipe_inode_info *pipe1,
                       struct pipe_inode_info *pipe2)
 {
@@ -361,8 +374,7 @@ 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_path.dentry->d_inode;
-        struct pipe_inode_info *pipe;
+        struct pipe_inode_info *pipe = filp->private_data;
         int do_wakeup;
         ssize_t ret;
         struct iovec *iov = (struct iovec *)_iov;
@@ -375,8 +387,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
 
         do_wakeup = 0;
         ret = 0;
-        mutex_lock(&inode->i_mutex);
-        pipe = inode->i_pipe;
+        __pipe_lock(pipe);
         for (;;) {
                 int bufs = pipe->nrbufs;
                 if (bufs) {
@@ -464,7 +475,7 @@ redo:
                 }
                 pipe_wait(pipe);
         }
-        mutex_unlock(&inode->i_mutex);
+        __pipe_unlock(pipe);
 
         /* Signal writers asynchronously that there is more room. */
         if (do_wakeup) {
@@ -486,8 +497,7 @@ 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_path.dentry->d_inode;
-        struct pipe_inode_info *pipe;
+        struct pipe_inode_info *pipe = filp->private_data;
         ssize_t ret;
         int do_wakeup;
         struct iovec *iov = (struct iovec *)_iov;
@@ -501,8 +511,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
 
         do_wakeup = 0;
         ret = 0;
-        mutex_lock(&inode->i_mutex);
-        pipe = inode->i_pipe;
+        __pipe_lock(pipe);
 
         if (!pipe->readers) {
                 send_sig(SIGPIPE, current, 0);
@@ -649,7 +658,7 @@ redo2:
                 pipe->waiting_writers--;
         }
 out:
-        mutex_unlock(&inode->i_mutex);
+        __pipe_unlock(pipe);
         if (do_wakeup) {
                 wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
                 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
@@ -662,29 +671,14 @@ out:
         return ret;
 }
 
-static ssize_t
-bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
-{
-        return -EBADF;
-}
-
-static ssize_t
-bad_pipe_w(struct file *filp, const char __user *buf, size_t count,
-           loff_t *ppos)
-{
-        return -EBADF;
-}
-
 static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-        struct inode *inode = filp->f_path.dentry->d_inode;
-        struct pipe_inode_info *pipe;
+        struct pipe_inode_info *pipe = filp->private_data;
         int count, buf, nrbufs;
 
         switch (cmd) {
                 case FIONREAD:
-                        mutex_lock(&inode->i_mutex);
-                        pipe = inode->i_pipe;
+                        __pipe_lock(pipe);
                         count = 0;
                         buf = pipe->curbuf;
                         nrbufs = pipe->nrbufs;
@@ -692,7 +686,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                                 count += pipe->bufs[buf].len;
                                 buf = (buf+1) & (pipe->buffers - 1);
                         }
-                        mutex_unlock(&inode->i_mutex);
+                        __pipe_unlock(pipe);
 
                         return put_user(count, (int __user *)arg);
                 default:
@@ -705,8 +699,7 @@ static unsigned int
 pipe_poll(struct file *filp, poll_table *wait)
 {
         unsigned int mask;
-        struct inode *inode = filp->f_path.dentry->d_inode;
-        struct pipe_inode_info *pipe = inode->i_pipe;
+        struct pipe_inode_info *pipe = filp->private_data;
         int nrbufs;
 
         poll_wait(filp, &pipe->wait, wait);
@@ -734,194 +727,56 @@ pipe_poll(struct file *filp, poll_table *wait)
 }
 
 static int
-pipe_release(struct inode *inode, int decr, int decw)
+pipe_release(struct inode *inode, struct file *file)
 {
-        struct pipe_inode_info *pipe;
+        struct pipe_inode_info *pipe = inode->i_pipe;
+        int kill = 0;
 
-        mutex_lock(&inode->i_mutex);
-        pipe = inode->i_pipe;
-        pipe->readers -= decr;
-        pipe->writers -= decw;
+        __pipe_lock(pipe);
+        if (file->f_mode & FMODE_READ)
+                pipe->readers--;
+        if (file->f_mode & FMODE_WRITE)
+                pipe->writers--;
 
-        if (!pipe->readers && !pipe->writers) {
-                free_pipe_info(inode);
-        } else {
+        if (pipe->readers || pipe->writers) {
                 wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM | POLLERR | POLLHUP);
                 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
                 kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
         }
-        mutex_unlock(&inode->i_mutex);
-
-        return 0;
-}
-
-static int
-pipe_read_fasync(int fd, struct file *filp, int on)
-{
-        struct inode *inode = filp->f_path.dentry->d_inode;
-        int retval;
-
-        mutex_lock(&inode->i_mutex);
-        retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers);
-        mutex_unlock(&inode->i_mutex);
-
-        return retval;
-}
-
-
-static int
-pipe_write_fasync(int fd, struct file *filp, int on)
-{
-        struct inode *inode = filp->f_path.dentry->d_inode;
-        int retval;
+        spin_lock(&inode->i_lock);
+        if (!--pipe->files) {
+                inode->i_pipe = NULL;
+                kill = 1;
+        }
+        spin_unlock(&inode->i_lock);
+        __pipe_unlock(pipe);
 
-        mutex_lock(&inode->i_mutex);
-        retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers);
-        mutex_unlock(&inode->i_mutex);
+        if (kill)
+                free_pipe_info(pipe);
 
-        return retval;
+        return 0;
 }
 
-
 static int
-pipe_rdwr_fasync(int fd, struct file *filp, int on)
+pipe_fasync(int fd, struct file *filp, int on)
 {
-        struct inode *inode = filp->f_path.dentry->d_inode;
-        struct pipe_inode_info *pipe = inode->i_pipe;
-        int retval;
+        struct pipe_inode_info *pipe = filp->private_data;
+        int retval = 0;
 
-        mutex_lock(&inode->i_mutex);
-        retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
-        if (retval >= 0) {
+        __pipe_lock(pipe);
+        if (filp->f_mode & FMODE_READ)
+                retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
+        if ((filp->f_mode & FMODE_WRITE) && retval >= 0) {
                 retval = fasync_helper(fd, filp, on, &pipe->fasync_writers);
-                if (retval < 0) /* this can happen only if on == T */
+                if (retval < 0 && (filp->f_mode & FMODE_READ))
+                        /* this can happen only if on == T */
                         fasync_helper(-1, filp, 0, &pipe->fasync_readers);
         }
-        mutex_unlock(&inode->i_mutex);
+        __pipe_unlock(pipe);
         return retval;
 }
 
-
-static int
-pipe_read_release(struct inode *inode, struct file *filp)
-{
-        return pipe_release(inode, 1, 0);
-}
-
-static int
-pipe_write_release(struct inode *inode, struct file *filp)
-{
-        return pipe_release(inode, 0, 1);
-}
-
-static int
-pipe_rdwr_release(struct inode *inode, struct file *filp)
-{
-        int decr, decw;
-
-        decr = (filp->f_mode & FMODE_READ) != 0;
-        decw = (filp->f_mode & FMODE_WRITE) != 0;
-        return pipe_release(inode, decr, decw);
-}
-
-static int
-pipe_read_open(struct inode *inode, struct file *filp)
-{
-        int ret = -ENOENT;
-
-        mutex_lock(&inode->i_mutex);
-
-        if (inode->i_pipe) {
-                ret = 0;
-                inode->i_pipe->readers++;
-        }
-
-        mutex_unlock(&inode->i_mutex);
-
-        return ret;
-}
-
-static int
-pipe_write_open(struct inode *inode, struct file *filp)
-{
-        int ret = -ENOENT;
-
-        mutex_lock(&inode->i_mutex);
-
-        if (inode->i_pipe) {
-                ret = 0;
-                inode->i_pipe->writers++;
-        }
-
-        mutex_unlock(&inode->i_mutex);
-
-        return ret;
-}
-
-static int
-pipe_rdwr_open(struct inode *inode, struct file *filp)
-{
-        int ret = -ENOENT;
-
-        mutex_lock(&inode->i_mutex);
-
-        if (inode->i_pipe) {
-                ret = 0;
-                if (filp->f_mode & FMODE_READ)
-                        inode->i_pipe->readers++;
-                if (filp->f_mode & FMODE_WRITE)
-                        inode->i_pipe->writers++;
-        }
-
-        mutex_unlock(&inode->i_mutex);
-
-        return ret;
-}
-
-/*
- * The file_operations structs are not static because they
- * are also used in linux/fs/fifo.c to do operations on FIFOs.
- *
- * Pipes reuse fifos' file_operations structs.
- */
-const struct file_operations read_pipefifo_fops = {
-        .llseek         = no_llseek,
-        .read           = do_sync_read,
-        .aio_read       = pipe_read,
-        .write          = bad_pipe_w,
-        .poll           = pipe_poll,
-        .unlocked_ioctl = pipe_ioctl,
-        .open           = pipe_read_open,
-        .release        = pipe_read_release,
-        .fasync         = pipe_read_fasync,
-};
-
-const struct file_operations write_pipefifo_fops = {
-        .llseek         = no_llseek,
-        .read           = bad_pipe_r,
-        .write          = do_sync_write,
-        .aio_write      = pipe_write,
-        .poll           = pipe_poll,
-        .unlocked_ioctl = pipe_ioctl,
-        .open           = pipe_write_open,
-        .release        = pipe_write_release,
-        .fasync         = pipe_write_fasync,
-};
-
-const struct file_operations rdwr_pipefifo_fops = {
-        .llseek         = no_llseek,
-        .read           = do_sync_read,
-        .aio_read       = pipe_read,
-        .write          = do_sync_write,
-        .aio_write      = pipe_write,
-        .poll           = pipe_poll,
-        .unlocked_ioctl = pipe_ioctl,
-        .open           = pipe_rdwr_open,
-        .release        = pipe_rdwr_release,
-        .fasync         = pipe_rdwr_fasync,
-};
-
-struct pipe_inode_info * alloc_pipe_info(struct inode *inode)
+struct pipe_inode_info *alloc_pipe_info(void)
 {
         struct pipe_inode_info *pipe;
 
@@ -931,8 +786,8 @@ struct pipe_inode_info * alloc_pipe_info(struct inode *inode)
                 if (pipe->bufs) {
                         init_waitqueue_head(&pipe->wait);
                         pipe->r_counter = pipe->w_counter = 1;
-                        pipe->inode = inode;
                         pipe->buffers = PIPE_DEF_BUFFERS;
+                        mutex_init(&pipe->mutex);
                         return pipe;
                 }
                 kfree(pipe);
@@ -941,7 +796,7 @@ struct pipe_inode_info * alloc_pipe_info(struct inode *inode)
         return NULL;
 }
 
-void __free_pipe_info(struct pipe_inode_info *pipe)
+void free_pipe_info(struct pipe_inode_info *pipe)
 {
         int i;
 
@@ -956,12 +811,6 @@ void __free_pipe_info(struct pipe_inode_info *pipe)
         kfree(pipe);
 }
 
-void free_pipe_info(struct inode *inode)
-{
-        __free_pipe_info(inode->i_pipe);
-        inode->i_pipe = NULL;
-}
-
 static struct vfsmount *pipe_mnt __read_mostly;
 
 /*
@@ -987,13 +836,14 @@ static struct inode * get_pipe_inode(void)
 
         inode->i_ino = get_next_ino();
 
-        pipe = alloc_pipe_info(inode);
+        pipe = alloc_pipe_info();
         if (!pipe)
                 goto fail_iput;
-        inode->i_pipe = pipe;
 
+        inode->i_pipe = pipe;
+        pipe->files = 2;
         pipe->readers = pipe->writers = 1;
-        inode->i_fop = &rdwr_pipefifo_fops;
+        inode->i_fop = &pipefifo_fops;
 
         /*
          * Mark the inode dirty from the very beginning,
@@ -1036,17 +886,19 @@ int create_pipe_files(struct file **res, int flags)
         d_instantiate(path.dentry, inode);
 
         err = -ENFILE;
-        f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops);
-        if (!f)
+        f = alloc_file(&path, FMODE_WRITE, &pipefifo_fops);
+        if (IS_ERR(f))
                 goto err_dentry;
 
         f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT));
+        f->private_data = inode->i_pipe;
 
-        res[0] = alloc_file(&path, FMODE_READ, &read_pipefifo_fops);
-        if (!res[0])
+        res[0] = alloc_file(&path, FMODE_READ, &pipefifo_fops);
+        if (IS_ERR(res[0]))
                 goto err_file;
 
         path_get(&path);
+        res[0]->private_data = inode->i_pipe;
         res[0]->f_flags = O_RDONLY | (flags & O_NONBLOCK);
         res[1] = f;
         return 0;
@@ -1054,12 +906,12 @@ int create_pipe_files(struct file **res, int flags)
 err_file:
         put_filp(f);
 err_dentry:
-        free_pipe_info(inode);
+        free_pipe_info(inode->i_pipe);
         path_put(&path);
         return err;
 
 err_inode:
-        free_pipe_info(inode);
+        free_pipe_info(inode->i_pipe);
         iput(inode);
         return err;
 }
@@ -1141,6 +993,168 @@ SYSCALL_DEFINE1(pipe, int __user *, fildes)
         return sys_pipe2(fildes, 0);
 }
 
+static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt)
+{
+        int cur = *cnt; 
+
+        while (cur == *cnt) {
+                pipe_wait(pipe);
+                if (signal_pending(current))
+                        break;
+        }
+        return cur == *cnt ? -ERESTARTSYS : 0;
+}
+
+static void wake_up_partner(struct pipe_inode_info *pipe)
+{
+        wake_up_interruptible(&pipe->wait);
+}
+
+static int fifo_open(struct inode *inode, struct file *filp)
+{
+        struct pipe_inode_info *pipe;
+        bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC;
+        int kill = 0;
+        int ret;
+
+        filp->f_version = 0;
+
+        spin_lock(&inode->i_lock);
+        if (inode->i_pipe) {
+                pipe = inode->i_pipe;
+                pipe->files++;
+                spin_unlock(&inode->i_lock);
+        } else {
+                spin_unlock(&inode->i_lock);
+                pipe = alloc_pipe_info();
+                if (!pipe)
+                        return -ENOMEM;
+                pipe->files = 1;
+                spin_lock(&inode->i_lock);
+                if (unlikely(inode->i_pipe)) {
+                        inode->i_pipe->files++;
+                        spin_unlock(&inode->i_lock);
+                        free_pipe_info(pipe);
+                        pipe = inode->i_pipe;
+                } else {
+                        inode->i_pipe = pipe;
+                        spin_unlock(&inode->i_lock);
+                }
+        }
+        filp->private_data = pipe;
+        /* OK, we have a pipe and it's pinned down */
+
+        __pipe_lock(pipe);
+
+        /* We can only do regular read/write on fifos */
+        filp->f_mode &= (FMODE_READ | FMODE_WRITE);
+
+        switch (filp->f_mode) {
+        case FMODE_READ:
+        /*
+         *  O_RDONLY
+         *  POSIX.1 says that O_NONBLOCK means return with the FIFO
+         *  opened, even when there is no process writing the FIFO.
+         */
+                pipe->r_counter++;
+                if (pipe->readers++ == 0)
+                        wake_up_partner(pipe);
+
+                if (!is_pipe && !pipe->writers) {
+                        if ((filp->f_flags & O_NONBLOCK)) {
+                                /* suppress POLLHUP until we have
+                                 * seen a writer */
+                                filp->f_version = pipe->w_counter;
+                        } else {
+                                if (wait_for_partner(pipe, &pipe->w_counter))
+                                        goto err_rd;
+                        }
+                }
+                break;
+        
+        case FMODE_WRITE:
+        /*
+         *  O_WRONLY
+         *  POSIX.1 says that O_NONBLOCK means return -1 with
+         *  errno=ENXIO when there is no process reading the FIFO.
+         */
+                ret = -ENXIO;
+                if (!is_pipe && (filp->f_flags & O_NONBLOCK) && !pipe->readers)
+                        goto err;
+
+                pipe->w_counter++;
+                if (!pipe->writers++)
+                        wake_up_partner(pipe);
+
+                if (!is_pipe && !pipe->readers) {
+                        if (wait_for_partner(pipe, &pipe->r_counter))
+                                goto err_wr;
+                }
+                break;
+        
+        case FMODE_READ | FMODE_WRITE:
+        /*
+         *  O_RDWR
+         *  POSIX.1 leaves this case "undefined" when O_NONBLOCK is set.
+         *  This implementation will NEVER block on a O_RDWR open, since
+         *  the process can at least talk to itself.
+         */
+
+                pipe->readers++;
+                pipe->writers++;
+                pipe->r_counter++;
+                pipe->w_counter++;
+                if (pipe->readers == 1 || pipe->writers == 1)
+                        wake_up_partner(pipe);
+                break;
+
+        default:
+                ret = -EINVAL;
+                goto err;
+        }
+
+        /* Ok! */
+        __pipe_unlock(pipe);
+        return 0;
+
+err_rd:
+        if (!--pipe->readers)
+                wake_up_interruptible(&pipe->wait);
+        ret = -ERESTARTSYS;
+        goto err;
+
+err_wr:
+        if (!--pipe->writers)
+                wake_up_interruptible(&pipe->wait);
+        ret = -ERESTARTSYS;
+        goto err;
+
+err:
+        spin_lock(&inode->i_lock);
+        if (!--pipe->files) {
+                inode->i_pipe = NULL;
+                kill = 1;
+        }
+        spin_unlock(&inode->i_lock);
+        __pipe_unlock(pipe);
+        if (kill)
+                free_pipe_info(pipe);
+        return ret;
+}
+
+const struct file_operations pipefifo_fops = {
+        .open           = fifo_open,
+        .llseek         = no_llseek,
+        .read           = do_sync_read,
+        .aio_read       = pipe_read,
+        .write          = do_sync_write,
+        .aio_write      = pipe_write,
+        .poll           = pipe_poll,
+        .unlocked_ioctl = pipe_ioctl,
+        .release        = pipe_release,
+        .fasync         = pipe_fasync,
+};
+
 /*
  * Allocate a new array of pipe buffers and copy the info over. Returns the
  * pipe size if successful, or return -ERROR on error.
@@ -1226,9 +1240,7 @@ int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
  */
 struct pipe_inode_info *get_pipe_info(struct file *file)
 {
-        struct inode *i = file->f_path.dentry->d_inode;
-
-        return S_ISFIFO(i->i_mode) ? i->i_pipe : NULL;
+        return file->f_op == &pipefifo_fops ? file->private_data : NULL;
 }
 
 long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
@@ -1240,7 +1252,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
         if (!pipe)
                 return -EBADF;
 
-        mutex_lock(&pipe->inode->i_mutex);
+        __pipe_lock(pipe);
 
         switch (cmd) {
         case F_SETPIPE_SZ: {
@@ -1269,7 +1281,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
         }
 
 out:
-        mutex_unlock(&pipe->inode->i_mutex);
+        __pipe_unlock(pipe);
         return ret;
 }