Introduce a handy list_first_entry macro

[linux.git] / fs / pipe.c

diff --git a/fs/pipe.c b/fs/pipe.c
index b1626f269a3445e38f34c1bc338734e0893bbd32..3a89592bdf577930b4c1698c4811261aa467cbf2 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -16,6 +16,7 @@
 #include <linux/uio.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
+#include <linux/audit.h>
 
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>
@@ -207,7 +208,7 @@ 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 +223,7 @@ 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 +244,7 @@ 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 +336,7 @@ 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 +366,7 @@ 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 +521,7 @@ 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 +549,7 @@ 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 +602,7 @@ 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 +619,7 @@ 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 +636,7 @@ 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 +757,7 @@ 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 +769,7 @@ 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 +781,7 @@ 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,
@@ -830,11 +831,28 @@ 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;
+}
+
+/*
+ * pipefs_dname() is called from d_path().
+ */
+static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+       return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]",
+                               dentry->d_inode->i_ino);
 }
 
 static struct dentry_operations pipefs_dentry_operations = {
        .d_delete       = pipefs_delete_dentry,
+       .d_dname        = pipefs_dname,
 };
 
 static struct inode * get_pipe_inode(void)
@@ -880,8 +898,7 @@ struct file *create_write_pipe(void)
        struct inode *inode;
        struct file *f;
        struct dentry *dentry;
-       char name[32];
-       struct qstr this;
+       struct qstr name = { .name = "" };
 
        f = get_empty_filp();
        if (!f)
@@ -891,19 +908,21 @@ struct file *create_write_pipe(void)
        if (!inode)
                goto err_file;
 
-       sprintf(name, "[%lu]", inode->i_ino);
-       this.name = name;
-       this.len = strlen(name);
-       this.hash = inode->i_ino; /* will go */
        err = -ENOMEM;
-       dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this);
+       dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name);
        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 +942,9 @@ 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 +955,9 @@ 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;
@@ -972,6 +992,10 @@ int do_pipe(int *fd)
                goto err_fdr;
        fdw = error;
 
+       error = audit_fd_pair(fdr, fdw);
+       if (error < 0)
+               goto err_fdw;
+
        fd_install(fdr, fr);
        fd_install(fdw, fw);
        fd[0] = fdr;
@@ -979,9 +1003,13 @@ int do_pipe(int *fd)
 
        return 0;
 
+ err_fdw:
+       put_unused_fd(fdw);
  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);