Pull asus into release branch
[pandora-kernel.git] / fs / splice.c
index a567010..5428b0f 100644 (file)
@@ -42,7 +42,7 @@ struct splice_pipe_desc {
        struct partial_page *partial;   /* pages[] may not be contig */
        int nr_pages;                   /* number of pages in map */
        unsigned int flags;             /* splice flags */
-       struct pipe_buf_operations *ops;/* ops associated with output pipe */
+       const struct pipe_buf_operations *ops;/* ops associated with output pipe */
 };
 
 /*
@@ -74,7 +74,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
                wait_on_page_writeback(page);
 
                if (PagePrivate(page))
-                       try_to_release_page(page, mapping_gfp_mask(mapping));
+                       try_to_release_page(page, GFP_KERNEL);
 
                /*
                 * If we succeeded in removing the mapping, set LRU flag
@@ -139,7 +139,7 @@ error:
        return err;
 }
 
-static struct pipe_buf_operations page_cache_pipe_buf_ops = {
+static const struct pipe_buf_operations page_cache_pipe_buf_ops = {
        .can_merge = 0,
        .map = generic_pipe_buf_map,
        .unmap = generic_pipe_buf_unmap,
@@ -159,7 +159,7 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
        return generic_pipe_buf_steal(pipe, buf);
 }
 
-static struct pipe_buf_operations user_page_pipe_buf_ops = {
+static const struct pipe_buf_operations user_page_pipe_buf_ops = {
        .can_merge = 0,
        .map = generic_pipe_buf_map,
        .unmap = generic_pipe_buf_unmap,
@@ -333,7 +333,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                                break;
 
                        error = add_to_page_cache_lru(page, mapping, index,
-                                             mapping_gfp_mask(mapping));
+                                             GFP_KERNEL);
                        if (unlikely(error)) {
                                page_cache_release(page);
                                if (error == -EEXIST)
@@ -557,7 +557,6 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 {
        struct file *file = sd->file;
        struct address_space *mapping = file->f_mapping;
-       gfp_t gfp_mask = mapping_gfp_mask(mapping);
        unsigned int offset, this_len;
        struct page *page;
        pgoff_t index;
@@ -577,76 +576,21 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        if (this_len + offset > PAGE_CACHE_SIZE)
                this_len = PAGE_CACHE_SIZE - offset;
 
-       /*
-        * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full
-        * page.
-        */
-       if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) {
-               /*
-                * If steal succeeds, buf->page is now pruned from the
-                * pagecache and we can reuse it. The page will also be
-                * locked on successful return.
-                */
-               if (buf->ops->steal(pipe, buf))
-                       goto find_page;
-
-               page = buf->page;
-               if (add_to_page_cache(page, mapping, index, gfp_mask)) {
-                       unlock_page(page);
-                       goto find_page;
-               }
-
-               page_cache_get(page);
-
-               if (!(buf->flags & PIPE_BUF_FLAG_LRU))
-                       lru_cache_add(page);
-       } else {
 find_page:
-               page = find_lock_page(mapping, index);
-               if (!page) {
-                       ret = -ENOMEM;
-                       page = page_cache_alloc_cold(mapping);
-                       if (unlikely(!page))
-                               goto out_ret;
-
-                       /*
-                        * This will also lock the page
-                        */
-                       ret = add_to_page_cache_lru(page, mapping, index,
-                                                   gfp_mask);
-                       if (unlikely(ret))
-                               goto out;
-               }
+       page = find_lock_page(mapping, index);
+       if (!page) {
+               ret = -ENOMEM;
+               page = page_cache_alloc_cold(mapping);
+               if (unlikely(!page))
+                       goto out_ret;
 
                /*
-                * We get here with the page locked. If the page is also
-                * uptodate, we don't need to do more. If it isn't, we
-                * may need to bring it in if we are not going to overwrite
-                * the full page.
+                * This will also lock the page
                 */
-               if (!PageUptodate(page)) {
-                       if (this_len < PAGE_CACHE_SIZE) {
-                               ret = mapping->a_ops->readpage(file, page);
-                               if (unlikely(ret))
-                                       goto out;
-
-                               lock_page(page);
-
-                               if (!PageUptodate(page)) {
-                                       /*
-                                        * Page got invalidated, repeat.
-                                        */
-                                       if (!page->mapping) {
-                                               unlock_page(page);
-                                               page_cache_release(page);
-                                               goto find_page;
-                                       }
-                                       ret = -EIO;
-                                       goto out;
-                               }
-                       } else
-                               SetPageUptodate(page);
-               }
+               ret = add_to_page_cache_lru(page, mapping, index,
+                                           GFP_KERNEL);
+               if (unlikely(ret))
+                       goto out;
        }
 
        ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
@@ -683,18 +627,25 @@ find_page:
        }
 
        ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
-       if (!ret) {
+       if (ret) {
+               if (ret == AOP_TRUNCATED_PAGE) {
+                       page_cache_release(page);
+                       goto find_page;
+               }
+               if (ret < 0)
+                       goto out;
                /*
-                * Return the number of bytes written and mark page as
-                * accessed, we are now done!
+                * Partial write has happened, so 'ret' already initialized by
+                * number of bytes written, Where is nothing we have to do here.
                 */
+       } else
                ret = this_len;
-               mark_page_accessed(page);
-               balance_dirty_pages_ratelimited(mapping);
-       } else if (ret == AOP_TRUNCATED_PAGE) {
-               page_cache_release(page);
-               goto find_page;
-       }
+       /*
+        * Return the number of bytes written and mark page as
+        * accessed, we are now done!
+        */
+       mark_page_accessed(page);
+       balance_dirty_pages_ratelimited(mapping);
 out:
        page_cache_release(page);
        unlock_page(page);
@@ -707,9 +658,9 @@ out_ret:
  * key here is the 'actor' worker passed in that actually moves the data
  * to the wanted destination. See pipe_to_file/pipe_to_sendpage above.
  */
-ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
-                        loff_t *ppos, size_t len, unsigned int flags,
-                        splice_actor *actor)
+ssize_t __splice_from_pipe(struct pipe_inode_info *pipe,
+                          struct file *out, loff_t *ppos, size_t len,
+                          unsigned int flags, splice_actor *actor)
 {
        int ret, do_wakeup, err;
        struct splice_desc sd;
@@ -722,13 +673,10 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
        sd.file = out;
        sd.pos = *ppos;
 
-       if (pipe->inode)
-               mutex_lock(&pipe->inode->i_mutex);
-
        for (;;) {
                if (pipe->nrbufs) {
                        struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
-                       struct pipe_buf_operations *ops = buf->ops;
+                       const struct pipe_buf_operations *ops = buf->ops;
 
                        sd.len = buf->len;
                        if (sd.len > sd.total_len)
@@ -797,9 +745,6 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
                pipe_wait(pipe);
        }
 
-       if (pipe->inode)
-               mutex_unlock(&pipe->inode->i_mutex);
-
        if (do_wakeup) {
                smp_mb();
                if (waitqueue_active(&pipe->wait))
@@ -809,6 +754,74 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
 
        return ret;
 }
+EXPORT_SYMBOL(__splice_from_pipe);
+
+ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
+                        loff_t *ppos, size_t len, unsigned int flags,
+                        splice_actor *actor)
+{
+       ssize_t ret;
+       struct inode *inode = out->f_mapping->host;
+
+       /*
+        * The actor worker might be calling ->prepare_write and
+        * ->commit_write. Most of the time, these expect i_mutex to
+        * be held. Since this may result in an ABBA deadlock with
+        * pipe->inode, we have to order lock acquiry here.
+        */
+       inode_double_lock(inode, pipe->inode);
+       ret = __splice_from_pipe(pipe, out, ppos, len, flags, actor);
+       inode_double_unlock(inode, pipe->inode);
+
+       return ret;
+}
+
+/**
+ * generic_file_splice_write_nolock - generic_file_splice_write without mutexes
+ * @pipe:      pipe info
+ * @out:       file to write to
+ * @len:       number of bytes to splice
+ * @flags:     splice modifier flags
+ *
+ * Will either move or copy pages (determined by @flags options) from
+ * the given pipe inode to the given file. The caller is responsible
+ * for acquiring i_mutex on both inodes.
+ *
+ */
+ssize_t
+generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out,
+                                loff_t *ppos, size_t len, unsigned int flags)
+{
+       struct address_space *mapping = out->f_mapping;
+       struct inode *inode = mapping->host;
+       ssize_t ret;
+       int err;
+
+       err = remove_suid(out->f_path.dentry);
+       if (unlikely(err))
+               return err;
+
+       ret = __splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
+       if (ret > 0) {
+               *ppos += ret;
+
+               /*
+                * If file or inode is SYNC and we actually wrote some data,
+                * sync it.
+                */
+               if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
+                       err = generic_osync_inode(inode, mapping,
+                                                 OSYNC_METADATA|OSYNC_DATA);
+
+                       if (err)
+                               ret = err;
+               }
+       }
+
+       return ret;
+}
+
+EXPORT_SYMBOL(generic_file_splice_write_nolock);
 
 /**
  * generic_file_splice_write - splice data from a pipe to a file
@@ -826,12 +839,21 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
                          loff_t *ppos, size_t len, unsigned int flags)
 {
        struct address_space *mapping = out->f_mapping;
+       struct inode *inode = mapping->host;
        ssize_t ret;
+       int err;
+
+       err = should_remove_suid(out->f_path.dentry);
+       if (unlikely(err)) {
+               mutex_lock(&inode->i_mutex);
+               err = __remove_suid(out->f_path.dentry, err);
+               mutex_unlock(&inode->i_mutex);
+               if (err)
+                       return err;
+       }
 
        ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
        if (ret > 0) {
-               struct inode *inode = mapping->host;
-
                *ppos += ret;
 
                /*
@@ -839,8 +861,6 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
                 * sync it.
                 */
                if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
-                       int err;
-
                        mutex_lock(&inode->i_mutex);
                        err = generic_osync_inode(inode, mapping,
                                                  OSYNC_METADATA|OSYNC_DATA);
@@ -941,7 +961,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
         * randomly drop data for eg socket -> socket splicing. Use the
         * piped splicing for that!
         */
-       i_mode = in->f_dentry->d_inode->i_mode;
+       i_mode = in->f_path.dentry->d_inode->i_mode;
        if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode)))
                return -EINVAL;
 
@@ -1041,6 +1061,19 @@ out_release:
 
 EXPORT_SYMBOL(do_splice_direct);
 
+/*
+ * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
+ * location, so checking ->i_pipe is not enough to verify that this is a
+ * pipe.
+ */
+static inline struct pipe_inode_info *pipe_info(struct inode *inode)
+{
+       if (S_ISFIFO(inode->i_mode))
+               return inode->i_pipe;
+
+       return NULL;
+}
+
 /*
  * Determine where to splice to/from.
  */
@@ -1052,7 +1085,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
        loff_t offset, *off;
        long ret;
 
-       pipe = in->f_dentry->d_inode->i_pipe;
+       pipe = pipe_info(in->f_path.dentry->d_inode);
        if (pipe) {
                if (off_in)
                        return -ESPIPE;
@@ -1073,7 +1106,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
                return ret;
        }
 
-       pipe = out->f_dentry->d_inode->i_pipe;
+       pipe = pipe_info(out->f_path.dentry->d_inode);
        if (pipe) {
                if (off_out)
                        return -ESPIPE;
@@ -1231,7 +1264,7 @@ static int get_iovec_page_array(const struct iovec __user *iov,
 static long do_vmsplice(struct file *file, const struct iovec __user *iov,
                        unsigned long nr_segs, unsigned int flags)
 {
-       struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe;
+       struct pipe_inode_info *pipe;
        struct page *pages[PIPE_BUFFERS];
        struct partial_page partial[PIPE_BUFFERS];
        struct splice_pipe_desc spd = {
@@ -1241,7 +1274,8 @@ static long do_vmsplice(struct file *file, const struct iovec __user *iov,
                .ops = &user_page_pipe_buf_ops,
        };
 
-       if (unlikely(!pipe))
+       pipe = pipe_info(file->f_path.dentry->d_inode);
+       if (!pipe)
                return -EBADF;
        if (unlikely(nr_segs > UIO_MAXIOV))
                return -EINVAL;
@@ -1400,13 +1434,7 @@ static int link_pipe(struct pipe_inode_info *ipipe,
         * grabbing by inode address. Otherwise two different processes
         * could deadlock (one doing tee from A -> B, the other from B -> A).
         */
-       if (ipipe->inode < opipe->inode) {
-               mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_PARENT);
-               mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_CHILD);
-       } else {
-               mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_PARENT);
-               mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_CHILD);
-       }
+       inode_double_lock(ipipe->inode, opipe->inode);
 
        do {
                if (!opipe->readers) {
@@ -1450,8 +1478,7 @@ static int link_pipe(struct pipe_inode_info *ipipe,
                i++;
        } while (len);
 
-       mutex_unlock(&ipipe->inode->i_mutex);
-       mutex_unlock(&opipe->inode->i_mutex);
+       inode_double_unlock(ipipe->inode, opipe->inode);
 
        /*
         * If we put data in the output pipe, wakeup any potential readers.
@@ -1475,8 +1502,8 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 static long do_tee(struct file *in, struct file *out, size_t len,
                   unsigned int flags)
 {
-       struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe;
-       struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe;
+       struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode);
+       struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode);
        int ret = -EINVAL;
 
        /*